Method of making articles from glass and glass ceramic articles so produced

ES 2 295 396 T3

DESCRIPTION

Method of manufacturing articles from glass and glass-ceramic articles thus produced.

The present invention relates to a method of manufacturing an article by coalescing a plurality of glass particles. Examples of such items include kitchen utensils (eg, plates), tooth holders and reinforced fibers, cutting tool inserts, abrasives, and structural components of gas engines (eg, valves and bearings).

A large number of glass compositions and glass-ceramic materials are known. Well known glass formers such as SiO are used in most oxide-based glass systems.₂, B₂OR₃, P₂OR₅, GeO₂, TeO₂, As₂OR₃ and V₂OR₅, in order to aid in the formation of the glass. Some of the glass compositions formed with these glass formers can be heat treated to form glass-ceramic compositions. The upper temperature of use of glasses and glass ceramics formed from such glass formers is generally less than 1200 ° C, typically about 700-800 ° C. Ceramic glasses tend to be more resistant to temperature than the glasses from which they are formed.

Although a large number of amorphous metal oxides can be obtained by melting and rapid quenching, most, due to the need for very high cooling rates to provide an amorphous rather than crystalline material, cannot be formed in bulky or complex molds. . Generally, such systems are very unstable to crystallization during subsequent annealing and therefore do not exhibit typical glass properties, such as viscous flow. On the other hand, glasses based on known network-forming oxides (for example, SiO₂ and B₂OR₃) are generally relatively stable to crystallization during annealing and correspondingly the "working" range in which viscous flow occurs is readily accessible. The formation of large articles from known glasses (for example, SiO₂ and B₂OR₃) via viscous sintering at temperatures above the glass transition temperature. For example, in the abrasives industry, grinding wheels are manufactured using vitrified binders to ensure that the abrasive particles are held together.

In WO 02/08146 A1 a melting crystalline eutectic material is described comprising the eutectic Al₂OR₃-Rare earth oxide-ZrO₂. Examples of useful articles comprising the eutectic melt material include abrasive fibers and particles. Abrasive melt particles can be incorporated into abrasive products, such as coated abrasives, bonded abrasives, nonwoven abrasives, and abrasive brushes. The above document is included in the terms of Article 54 (3) EPC.

It is desirable to provide large articles and / or complex shapes comprising non-traditional glasses and glass-ceramic compositions.

The present invention provides methods of manufacturing articles as defined in claims 1, 5 and 9. Optionally, the articles may be a composite of two or more different glass compositions or formulations. In some embodiments, the glass is optionally heat treated in order to at least partially crystallize the glass. Further embodiments of the invention are defined in dependent claims 2 to 4, 6 to 8 and 10.

In one embodiment of the present invention there is provided a method of manufacturing a glass article comprising:

providing a substrate (eg, ceramics, metals, intermetallic materials, and composites of the foregoing) embedded in an external surface;

provide at least a first glass (e.g. sheets, particles (microspheres included) and fibers), such that the first glass comprises at least two different metal oxides (i.e. the metal oxides do not have the same cation (s)) , in which the first glass has a vitrification temperature T_g and a crystallization temperature T_x, and in which the difference between the T_g and T_x of the first glass is at least 5K (or even, at least 10K, at least 15K, at least 20K, at least 25K, at least 30K, or at least 35K), with the first glass containing less than 20% by weight SiO₂ (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of SiO₂), less than 20% by weight of B₂OR₃ (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of B₂OR₃), and less than 40% by weight of P₂OR₅ (or even less than 35%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of P₂OR₅);

heating the first glass above the Tg to a temperature such that at least a part of the glass wets at least a part of the outer surface of the substrate when in contact with it; and cooling the glass to provide an article comprising a ceramic comprising the glass bonded to at least a portion of the outer surface of the substrate. In some embodiments, the ceramic is a glass. Optionally, the method can be practiced with a second, a third or more different glasses, including glasses that have, respectively, Tg and Tx, and in which the difference between each Tg and Tx of a glass is at

ES 2 295 396 T3 minus 5K (or even, at least 10K, at least 15K, at least 20K, at least 25K, at least 30K or at least 35K), wherein one or more of the additional glasses optionally contains less than 20% by weight of SiO₂ (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of SiO₂), less than 20% by weight of B₂OR₃ (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of B₂OR₃) and less than 40% by weight of P₂OR₅ (or even less than 35%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of P₂OR₅). Preferably, the glass, or if more than one glass is used, at least one of the glasses comprises less than 40 percent (preferably, less than 35, 30, 25, 20, 15, 10, 5, or even 0) by weight of SiO glass₂, B₂OR₃ And p₂OR₅collectively, with respect to the total weight of the glass.

In some embodiments of the present invention, the first glass is provided as at least a first plurality of particles comprising glass (including glass particles).

In another embodiment of the present invention there is provided a method of manufacturing an article comprising:

providing at least a first glass and a second glass (e.g. sheets, particles (microspheres included) and fibers) in which the first glass comprises at least two different metal oxides, in which the first glass has a T_g1 and a T_x1, and in which the difference between the T_g1 and the T_x1 is at least 5K (or even, at least 10K, at least 15K, at least 20K, at least 25K, at least 30K, or at least 35K), the first glass containing less than 20% by weight SiO₂ (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of SiO₂), less than 20% by weight of B₂OR₃ (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of B₂OR₃), and less than 40% by weight of P₂OR₅ (or even less than 35%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of P₂OR₅);

heat the first and second glasses above at least T_g1with at least the first glass coalescing with the second glass to provide the article. Optionally, the second glass has a T_g2 and a T_x2, so that the difference between T_g2 and T_x2 it's at least 5K (or even, at least 10K, at least 15K, at least 20k, at least 25K, at least 30K, or at least 35K). Optionally, the second glass contains less than 20% by weight of SiO2 (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of SiO₂), less than 20% by weight of B₂OR₃ (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of B₂OR₃) and less than 40% by weight of P₂OR₅ (or even less than 35%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of P₂OR₅). Optionally, the method can be implemented with a third, a fourth glass, etc., including glasses that have, respectively, a T_g and a T_x, and in which the difference between each T_g and T_x of a glass is at least 5K (or even, at least 10K, at least 15K, at least 20K, at least 25K, at least 30K, or at least 35K), wherein one or more of the additional glasses optionally contains less than 20% by weight of SiO2 (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of SiO₂), less than 20% by weight of B₂OR₃ (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of B₂OR₃) and less than 40% by weight of P₂OR₅ (or even less than 35%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of P₂OR₅). The glasses can have the same composition, different composition or combinations thereof. Preferably, at least one of the glasses comprises less than 40 (preferably, less than 35, 30, 25, 20, 15, 10, 5, or even 0) percent by weight of the SiO glass.₂, B₂OR₃, And p₂OR₅ collectively, with respect to the total weight of the glass.

In another embodiment of the present invention there is provided a method of manufacturing an article comprising:

providing at least a first glass and a second glass (e.g. sheets, particles (microspheres included) and fibers), in which the first glass comprises at least two different metal oxides, in which the first glass has a T_g1 and a T_x1, and in which the difference between the T_g1 and the T_x1 is at least 5K (or even at least 10K, at least 15K, at least 20K, at least 25K, at least 30K, or at least 35K), the first glass containing less than 20% by weight SiO₂ (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of SiO₂), less than 20% by weight of B₂OR₃ (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of B₂OR₃) and less than 40% by weight of P₂OR₅ (or even less than 35%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of P₂OR₅), and in which the second glass comprises at least two different metal oxides, in which the second glass has a Tg2 and a Tx2, and in which the difference between Tg2 and Tx2 is at least 5K (or even at minus 10K, at least 15K, at least 20K, at least 25K, at least 30K or at least 35K), the second glass containing less than 20% by weight of SiO₂ (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of SiO₂), less than 20% by weight of B₂OR₃ (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of B₂OR₃) and less than 40% by weight of P₂OR₅ (or even less than 35%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of P₂OR₅);

heating the glasses above the highest temperature of Tg1 or Tg2 and coalescing the first and second glasses to provide the article. Optionally, the method can be implemented with a third, a fourth glass,

ES 2 295 396 T3 etc., including glasses having, respectively, a T_g and a T_x, and in which the difference between each T_g and T_x of a glass is at least 5K (or even, at least 10K, at least 15K, at least 20K, at least 25K, at least 30k, or at least 35K), wherein one or more of the additional glasses optionally contains less than 20% by weight of SiO₂(or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of SiO₂), less than 20% by weight of B₂OR₃ (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of B₂OR₃) and less than 40% by weight of P₂OR₅ (or even less than 35%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of P₂OR₅). The glasses can have the same composition, different composition or combinations thereof. Preferably, at least one of the glasses comprises less than 40 (preferably, less than 35, 30, 25, 20, 15, 10, 5, or even 0) percent by weight of the SiO glass.₂, B₂OR₃, And p₂OR₅ collectively, with respect to the total weight of the glass.

In another embodiment of the present invention there is provided a method of manufacturing an article comprising:

providing at least a first plurality of glass-comprising particles (including glass particles) in which the glass comprises at least two different metal oxides, in which the glass has a Tg and a Tx, and in which the difference between the T_g and the T_x of the glass is at least 5K (or even, at least 10K, at least 15K, at least 20K, at least 25K, at least 30K or at least 35K), the glass containing less than 20% by weight of SiO2 (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of SiO₂), less than 20% by weight of B₂OR₃ (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of B₂OR₃) and less than 40% by weight of P₂OR₅ (or even less than 35%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of P₂OR₅);

heating the glass above the Tg and coalescing at least a portion of the first plurality of particles to provide the article. In some embodiments, the ceramic is a glass. Optionally, the method can be practiced with a second, a third or more different pluralities of particles comprising (different) glasses, including glasses having, respectively, a T_g and a T_x, in which the difference between each T_g and T_x of a glass is at least 5K (or even at least 10K, at least 15k, at least 20K, at least 25K, at least 30K, or at least 35K), and in which one or more of the additional glasses optionally contain less than 20% by weight of SiO₂ (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of SiO₂), less than 20% by weight of B₂OR₃ (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of B₂OR₃) and less than 40% by weight of P₂OR₅ (or even less than 35%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of P₂OR₅). Preferably, the glass or, if more than one glass is used, at least one of the glasses, comprises less than 40 (preferably less than 35, 30, 25, 20, 15, 10, 5 or even 0) percent by weight. SiO glass₂, B₂OR₃, And p₂OR₅ collectively, with respect to the total weight of the glass.

Desirably, the reason for the T_g a Ti is at least 0.5. Examples of useful glass particles include those comprising REO-Al2O3-ZrO2 and REO-Al2O3-ZrO2-SiO2 glasses. Other useful glasses may also include CaO-Al2O3, CaO-Al2O3 -ZrO2, BaO-TiO2, La2O3-TiO2, REO (ie, rare earth oxide (s)) Al2O3 glasses.

The embodiments of the method according to the present invention allow, even for certain ceramic compositions, the formation of shapes and sizes of articles that are not obtainable by conventional methods. Typically, glass coalescence is enhanced if the glass is under pressure during heating. In one embodiment, a glass filler (e.g., particles (including beads), fibers, etc.) is placed in a mold and hot pressure is exerted at temperatures above the glass transition temperature, where the viscous flow of the glass coalesces into an article.

In this application:

"Amorphous material" refers to a material derived from a molten and / or vapor phase that lacks any broad spectrum crystalline structure, determined by x-ray diffraction, and / or that has an exothermic peak corresponding to the crystallization of the amorphous material, determined by DTA (differential thermal analysis) by the test described in this document and entitled "Differential Thermal Analysis";

"Ceramic" includes amorphous material, glass, crystalline ceramic, glass-ceramic, and combinations of the foregoing;

"Glass" refers to an amorphous material that exhibits a glass transition temperature;

"Glass-ceramic" refers to a ceramic comprising crystals formed by heat treatment of the amorphous material;

"Rare earth oxides" refers to cerium oxide (eg, CeO₂), dysprosium oxide (eg, Dy₂OR₃), erbium oxide (eg, Er₂OR₃), europium oxide (eg, Eu₂OR₃), gadolinium oxide (eg, Gd₂OR₃), holmium oxide (eg, Ho₂OR₃), lanthanum oxide (eg, La₂OR₃), lutetium oxide (eg, Lu₂OR₃), neodymium oxide (eg, Nd₂OR₃), praseodymium oxide (eg, Pr₆On), samarium oxide (eg, Sm₂OR₃), terbium oxide (eg, Tb₂OR₃), thorium oxide (eg, Th₄OR₇), thulium oxide (eg, Tm₂OR₃), ytterbium oxide (eg, Yb₂OR₃) and combinations of the above;

ES 2 295 396 T3 "REO" refers to rare earth oxide (s);

"T_g"Refers to the glass transition temperature, as determined in Example 1;

"Tj" refers to the melting point of the glass; and "T_x"Refers to the crystallization initiation temperature, as determined in Example 1.

Furthermore, it is understood herein that unless it is stated that a metal oxide (e.g. Al₂OR₃, complex Al₂OR₃-metal oxide, etc.) is crystalline, for example, in a glass-ceramic material, said metal oxide can be amorphous, crystalline or have amorphous portions and crystalline portions. For example, if a glass-ceramic material comprises Al₂OR₃ and ZrO₂, the Al₂OR₃ and the ZrO₂ they can each be in the amorphous state, in the crystalline state or in portions in the amorphous state and portions in the crystalline state, or even as a reaction product with other metal oxide (s) (e.g., unless it is stated that, for example, Al₂OR₃ is present as Al₂OR₃crystalline or a specific crystalline phase of Al₂OR₃ (eg, alpha Al₂OR₃), may be present as Al₂OR₃ crystalline and / or as part of one or more crystalline complexes Al₂OR₃-metal oxides). Furthermore, it is understood that glass-ceramics formed by heating amorphous materials that do not exhibit a Tg may not actually comprise glass, but instead may comprise crystals and amorphous material that do not exhibit a Tg.

Optionally, certain glass articles made in accordance with the present invention may be heat treated to at least partially crystallize the glass to provide a glass-ceramic material.

Fig. 1 is a DTA curve of the material of Example 1; Y

Figs. 2-6 are DTA curves for the materials of Examples 2, 5, 6, 7, and 9, respectively.

In general, the ceramics according to the present invention can be made by heating (including flame) the sources of the appropriate metal oxides to form a melt, desirably a homogeneous melt, and then by quenching the melt to provide amorphous materials. or ceramics comprising amorphous materials. Amorphous and ceramic materials comprising amorphous materials according to the present invention can be manufactured, for example, by heating (including flame) of the sources of the appropriate metal oxides to form a melt, desirably a homogeneous melt, and then by cooling. rapid melt to provide amorphous material. The embodiments of the amorphous materials can be made, for example, by melting the sources of the metal oxides in any suitable furnace (eg, an induction heating furnace, a gas furnace or an electric furnace) or, by For example, in a plasma oven. The resulting melt is cooled (eg, by discharging the melt into a cooling medium (eg. eg, high speed air jets, liquids, metal plates (including tempered metal plates), metal rollers (including tempered metal rollers), metal balls (including tempered metal balls and the like).

Forms of embodiment of amorphous materials can also be obtained by other techniques, such as: laser fiber fusion with free fall cooling, Taylor spinning technique, plasmatron technique, hammer and anvil technique, centrifuge rapid cooling, cooling to air gun jet, single and double roller rapid cooling, laminating roller rapid cooling and hanging drop fusion extraction (see, p. eg, Rapid Solidification of Ceramics, Brockway et. al, Metals And Ceramics Information Center, A Department of Defense Information Analysis Center, Columbus, OH, January, 1984). Embodiments of amorphous materials can also be obtained by other techniques, such as: thermal pyrolysis (including flame, laser or plasma-assisted techniques) of suitable precursors, physical vapor synthesis (PVS) of metal precursors, and mechanochemical processing.

In one method, the glass useful for the present invention can be made using flame fusion, as described, for example, in US Patent No. 6,254,981 (Castle). In this method, the metal oxide source materials are fed (eg, in the form of particles, sometimes referred to as "feed particles") directly into a burner (eg. g., a methane-air burner, an acetylene-oxygen burner, a hydrogen-oxygen burner and the like), and then rapidly cooled in, for example, water, cooling oil, air or the like. The feed particles can be formed, for example, by grinding, agglomerating (eg, spray drying), melting or sintering from the metal oxide sources. The size of the feed particles introduced into the flame generally determines the size of the resulting glass beads / particles.

Examples of glasses useful in carrying out the present invention include those comprising CaO-Al2O3, CaO-Al glasses₂O3-ZrO2, BaO-TiO2, La2O3-TiO2, REO-Al₂OR₃, REO-A ^ O3-ZrO2, REO-Al₂O3-ZrO2-SiO2 and SrO-Al2O3 -ZrO2. Useful glass formulations include those of, or proximate to, the eutectic composition. In addition to the compositions CaO-Al2O3, CaO-Al2O3-ZrO2, BaO-TiO2, La2O3-TiO2, REO-Al2O3, REO-Al2O3-ZrO2, REO-Al2O3 -ZrO2 -SiO2 and SrO-Al2O3 -ZrO2, described in this document Other compositions, including eutectic compositions, will be of apparent utility to those skilled in the art after reviewing the present disclosure. For example, phase diagrams depicting various compositions, including eutectic compositions, are known in the art.

ES 2 295 396 T3

Surprisingly, it has been found that the ceramics of the present invention can be obtained without limitations as to their dimensions. This has been found to be possible through a coalescence step carried out at temperatures above the glass transition temperature. For example, as is evident from Fig. 1, a useful glass made by carrying out the present invention undergoes glass transition (T_g) before significant crystallization occurs (T_x), as evidenced by the existence of an endothermic event (T_g) at a temperature lower than that of the exothermic event (T_x). This fact allows large-scale manufacture of articles of any size from relatively small glass particles. More specifically, for example, an article according to the present invention can be provided by heating, for example, glass particles (including beads and microspheres), fibers, etc., useful in carrying out the present invention at temperatures above T_g, so that the glass particles etc. coalesce to compose a shape and after coalescence the shape is cooled to provide the article. In certain embodiments, the heating is conducted at at least one temperature in the range of about 725 ° C to about 1100 ° C.

Surprisingly, for certain embodiments according to the present invention, coalescence can be effected at temperatures significantly higher than the crystallization temperature (T_x). Without wishing to be bound by theory, it is believed that relatively low crystallization kinetics allow viscous flow to access higher temperatures. Typically, the glass is under pressure during coalescence to aid the coalescence of the glass. In one embodiment, a charge of glass particles, etc. is placed. in a mold and hot pressure is exerted at temperatures above the glass transition temperature, in which the viscous flow of the glass coalesces in a relatively large part. Typically, the amorphous material is under pressure (eg, greater than zero to 1 GPa or greater) during coalescence to aid the coalescence of the amorphous material. It is also within the scope of the present invention to effect additional coalescence to further improve the desirable properties of the article. For example, a hot hydrostatic pressure (eg, at temperatures from about 900 ° C to about 1400 ° C) can be exerted to remove residual porosity, increasing the density of the material. It is also within the scope of the present invention to coalesce the glass via hot isostatic pressure, hot extrusion, or other pressure-assisted techniques.

The heat treatment can be carried out in any of a wide variety of ways, including those known in the art for heat treatment of glasses, in order to provide glass-ceramic materials. For example, heat treatment can be carried out in batches, for example using resistive induction or gas heated furnaces. Alternatively, for example, the heat treatment can be carried out continuously, for example, by using rotary kilns. In the case of a rotary kiln, the material is fed directly into a kiln that is operating at elevated temperature. The residence time at elevated temperature can range from a few seconds (in some embodiments even less than 5 seconds) to a few minutes or several hours. The temperature can be, in any case, from 900 ° C to 1600 ° C, typically between 1200 ° C and 1500 ° C. It is also within the scope of the present invention to perform some of the heat treatments in batches (eg, for the nucleation step) and others continuously (eg, for the crystalline growth step and to achieve the desired density). For the nucleation step, in some embodiments the temperature is typically between about 900 ° C to about 1100 ° C, preferably in a range of about 925 ° C to about 1050 ° C. Similarly, for the densification step, in some embodiments the temperature is typically in a range of about 1100 ° C to about 1600 ° C, preferably in a range of about 1200 ° C to about 1500 ° C. This heat treatment can take place, for example, by feeding the material directly into an oven at elevated temperature. Alternatively, for example, the material can be fed into an oven at a much lower temperature (eg, room temperature), then heated to the desired temperature at a predetermined heating rate. It is within the scope of the present invention to effect the heat treatment in an atmosphere other than air. In some cases it may even be desirable to carry out the heat treatment in reducing atmosphere (s). Furthermore, for example, it may be desirable to carry out heat treatment under pressure of a gas, as in, for example, the cases of hot isostatic pressure or pressure gas furnace.

Sources, including commercial sources, of metal oxides, such as Al₂OR₃, BaO, CaO, rare earth oxides (e.g. CeO₂, Dy₂OR₃, Er₂OR₃, Eu₂OR₃, Gd₂OR₃, Ho₂OR₃, The₂OR₃, Lu₂OR₃, Nd₂OR₃, Pr₆On, Sm₂OR₃, Th₄OR₇, Tm₂OR₃, Yb₂OR₃ and combinations of the above), TiO_{2 and} ZrO₂. For example, the sources of Al₂OR₃ (with respect to theoretical oxide) include bauxite (including both natural and synthetically produced bauxite), calcined bauxite, hydrated aluminas (eg, boehmite and gibbsite), aluminum, Bayer process alumina, aluminum ore, gamma alumina, alpha alumina, aluminum salts, aluminum nitrates and combinations of the above. The source of Al₂OR₃ may contain, or only provide, Al₂OR₃. Alternatively, the source of Al₂OR₃ may contain or provide Al2O3 as well as one or more metal oxides other than Al2O3 (including complex materials containing Al₂OR₃-metal oxides (eg Dy₃To the₅I heard₂, Y₃To the₅I heard₂, CeAlnOi₈, etc.)).

Sources, including commercial sources, of rare earth oxides include rare earth oxide powders, rare earth metals, rare earth containing minerals (eg, bastnasite and monazite), rare earth salts, rare earth nitrates and rare earth carbonates. The source of the rare earth oxide (s) may contain, or only provide, the rare earth oxide (s). Alternatively, the rare earth oxide (s) may contain or provide the rare earth oxide (s) as well as one or more metal oxides other than rare earth oxide (s) (including complex materials containing rare earth oxide-other metal oxides (eg, Dy₃To the₅OR₁₂, CeAl₁₁OR₁₈, etc.)).

ES 2 295 396 T3

Sources, including commercial sources, of ZrO2 (relative to theoretical oxide) include zirconium oxide powders, zirconia sand, zirconia, zirconium-containing minerals, and zirconium salts (eg, carbonates, acetates, nitrates, chlorides , zirconium hydroxides and combinations of the above). In addition, or alternatively, the source of ZrO₂ may contain or provide ZrO₂ as well as other metal oxides, such as hafnia. Sources, including commercial sources, of HfO₂ (with respect to theoretical oxide) include hafnium oxide powders, hafnium, hafnium-containing minerals, and hafnium salts. In addition, or alternatively, the source of HfO₂ it can contain or provide HfO2 as well as other metal oxides, such as ZrO2.

Sources, including commercial sources, of BaO include barium oxide powders, barium-containing minerals, barium salts, barium nitrates, and barium carbonates. The barium oxide source may contain, or only provide, barium oxide. Alternatively, the barium oxide source may contain or provide barium oxide as well as one or more metal oxides other than barium oxide (including complex materials containing barium oxide and other metal oxides).

Sources, including commercial sources, of CaO include calcium oxide powders and calcium-containing minerals. The source of calcium oxide (s) may contain, or only provide, calcium oxide. Alternatively, the calcium oxide source may contain or provide calcium oxide as well as one or more metal oxides other than calcium oxide (including complex materials containing calcium oxide and other metal oxides).

Sources, including commercial sources, of rare earth oxides include rare earth oxide powders, rare earth metals, rare earth containing minerals (eg, bastnasite and monazite), rare earth salts, rare earth nitrates and rare earth carbonates. The source of the rare earth oxide (s) may contain, or only provide, the rare earth oxide (s). Alternatively, the rare earth oxide (s) may contain or provide the rare earth oxide (s), as well as one or more metal oxides other than the rare earth oxide (s) (including complex materials containing rare earth oxide- other metal oxides (e.g. Dy₃To the₅I heard₂, CeAlnOi₈, etc.)).

Sources, including commercial sources, of SiO2 include silica powders, silicic metals, and silicon-containing minerals. The silicon oxide source may contain, or only provide, silicon oxide. Alternatively, the silicon oxide source may contain or provide silicon oxide as well as one or more metal oxides other than silicon oxide (including complex materials containing silicon oxide and other metal oxides).

Sources, including commercial sources, of SrO include strontium oxide powders, strontium carbonates, and strontium-containing minerals. The strontium oxide source may contain, or only provide, strontium oxide. Alternatively, the strontium oxide source may contain or provide strontium oxide as well as one or more metal oxides other than strontium oxide (including complex materials containing calcium oxide and other metal oxides).

Sources, including commercial sources, of TiO2 include titanium oxide powders, titanium metals, and titanium-containing minerals. The titanium oxide source may contain, or only provide, titanium oxide. Alternatively, the titanium oxide source may contain or provide titanium oxide as well as one or more metal oxides other than titanium oxide (including complex materials containing titanium oxide and other metal oxides).

Sources, including commercial sources, of ZrO2 (relative to theoretical oxide) include zirconium oxide powders, zirconia sand, zirconia, zirconium-containing minerals, and zirconium salts (eg, carbonates, acetates, nitrates, chlorides , zirconium hydroxides and combinations of the above). In addition, or alternatively, the source of ZrO₂ may contain or provide ZrO₂ as well as other metal oxides, such as hafnia. Sources, including commercial sources, of HfO2 (relative to theoretical oxide) include hafnium oxide powders, hafnium, hafnium-containing minerals, and hafnium salts. Additionally, or alternatively, the HfO2 source may contain or provide HfO2 as well as other metal oxides, such as ZrO2.

Optionally, the ceramics according to the present invention further comprise metal oxides beyond those necessary for the general composition. The addition of certain metal oxides can alter the properties and / or the crystalline structure or the microstructure of the ceramics manufactured according to the present invention, as well as the processing of the starting materials and the intermediates in the manufacture of the ceramics. For example, it has been observed that additions of oxides, such as MgO, CaO, Li₂O and Na₂Or they alter the T so much_g like the T_x of the glass. Although not intended to be bound by theory, it is believed that such additions influence glass formation. Also, for example, such oxide additions can lower the melting temperature of the overall system (ie, direct the system toward a eutectic that melts at a lower temperature) and facilitate glass formation. Complex eutectics in multicomponent systems (quaternary, etc.) can result in better glass forming ability. The viscosity of the liquid melt and the viscosity of the glass in its "working" ranges can also be affected by the addition of metal oxides beyond that necessary for the overall composition.

In some examples, it may be preferred to incorporate limited amounts of metal oxides selected from the group consisting of Na₂O, P₂OR₅, Yes₂, TeO₂, V₂OR₃ and combinations of the above. Sources, including commercial sources, include the oxides themselves, complex oxides, minerals, carbonates, acetates, nitrates, chlorides, hydroxides, etc. These metal oxides can be added, for example, to modify a physical property of the resulting abrasive particles and / or to improve processing. In cases where these metal oxides are used, add

ES 2 295 396 T3 typically of more than 0% to 20% by weight, preferably more than 0% to 5% by weight and more preferably more than 0% to 2% by weight of glass-ceramic material, depending, for example, on the desired property.

Still other glass compositions that can be used in conjunction with the glasses required to carry out the present invention include those conventional glasses that are well known in the art, including sources thereof.

For glasses that devitrify to form glass ceramics, crystallization can also be affected by additions of materials beyond those necessary for the overall composition. For example, certain metals, metal oxides (eg, titanates and zirconates), and fluorides can act, for example, as nucleating agents, resulting in beneficial heterogeneous nucleation of crystals. Furthermore, the addition of some oxides can change the nature of metastable phases, devitrifying the glass during annealing. In another aspect, for ceramics according to the present invention comprising ZrO₂ crystalline, it may be desirable to add metal oxides (e.g., Y₂OR₃, Uncle₂, CaO and MgO) which are known to stabilize the tetragonal / cubic form of ZrO₂.

Examples of optional metal oxides (i.e., metal oxides beyond those necessary for the general composition) may include, with respect to theoretical oxide, Al₂OR₃, BaO, CaO, Cr₂OR₃, CoO, Fe₂OR₃, GeO₂, HfO₂, Li₂O, MgO, MaO, NiO, Na₂O, P₂OR₅, rare earth oxides, Sc₂OR₃, Yes₂, SrO, TeO₂, Uncle₂, V₂OR₃, Y₂OR₃, ZnO, ZrO₂and combinations of the above. Sources, including commercial sources, include the oxides themselves, complex oxides, minerals, carbonates, acetates, nitrates, chlorides, hydroxides, etc. Additionally, for example, with respect to Y2O3, sources, including commercial sources, of Y2O3 (with respect to theoretical oxide) include yttrium oxide powders, yttrium, yttrium-containing minerals, and yttrium salts (e.g. (e.g., yttrium carbonates, nitrates, chlorides and hydroxides and combinations of the above). The Y2O3 source may contain, or only provide, Y2O3. Alternatively, the Y2O3 source may contain or provide Y2O3 as well as one or more metal oxides other than Y₂OR₃ (including complex materials containing Y₂OR₃-metal oxides (eg, Y₃To the₅OR₁₂)).

In some embodiments it may be advantageous, for at least a portion of a metal oxide source (in some embodiments, preferably 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 or even at least 95 percent by weight), obtaining by adding a particulate metallic material comprising at least one of the metals M (p. g., Al, Ca, Cu, Cr, Fe, Li, Mg, Ni, Ag, Ti, Zr and combinations of the above) that has a negative oxide formation enthalpy or is obtained by addition to the melt of an alloy of the same metal or, otherwise, by adding the metal with the other starting materials. Although not intended to be bound by theory, it is believed that the heat resulting from the exothermic reaction associated with the oxidation of the metal is beneficial in the formation of a homogeneous melt, resulting in an amorphous material. For example, it is believed that the additional heat generated by the oxidation reaction in the starting material eliminates or minimizes insufficient heat transfer and, consequently, facilitates melt formation and homogeneity, particularly when forming amorphous particles with dimensions of x, y, and z above 150 microns. The availability of the additional heat is further believed to help drive various chemical reactions and physical processes (eg. g., densification and spheroidization) to completion. Additionally, it is believed that, for some embodiments, the presence of the additional heat generated by the oxidation reaction actually enables the formation of the melt, which would be difficult to obtain otherwise or would not be practical due to the high melting point of the compounds. materials. Furthermore, the presence of the additional heat generated by the oxidation reaction actually enables the formation of amorphous material that otherwise could not or could not be manufactured in the desired size range. Another advantage of the invention includes, as regards the formation of amorphous materials, that many of the physical and chemical processes, such as melting, densification and spheroidization, can be achieved in short periods of time, so that they can be achieved. reach very high cooling rates. For additional details, see the co-pending application for the US Publication Number. 2003/0110 709 A1, filed on the same date as this application.

The particular selection of sources of metal oxides and other additives for making ceramics in accordance with the present invention typically takes into account, for example, the desired composition and microstructure of the resulting ceramics, the desired degree of crystallinity, if any, the desired physical properties (eg. hardness or strength) of the resulting ceramics, avoid or minimize the presence of undesirable impurities, the desired characteristics of the resulting ceramics and / or the particular process (including equipment and any purification of the starting materials before and / or during melting and / or solidification) used to prepare the ceramics.

The sources of metal oxides and the other additives can be in any form suitable for the process and equipment used for the present invention. The starting materials can be melted and rapidly cooled by using techniques and equipment known in the art for making oxide glasses and amorphous metals. Desirable cooling rates include those of 50K / s and higher. Cooling techniques known in the art include roll cooling. Roll cooling can be carried out, for example, by melting the metal oxide sources at a temperature typically 20-200 ° C higher than the melting point and cooling / tempering the melt by spraying it at high pressure (e.g. g., using a gas, such as air, argon, nitrogen or the like) on a rotating high speed roller (s). Typically the rollers are made of metal and are water cooled. Metal book-shaped molds can also be useful for quenching / tempering the cast.

ES 2 295 396 T3

Other techniques for forming melts, quenched / tempered melts, and / or glass forming include vapor phase tempering, plasma spraying, melt extraction and gas atomization. Vapor phase tempering can be carried out, for example, by deposition of a thin layer (sputtering), in which the metal alloys or sources of metal oxides used are formed into a deposition target (s). The target is fixed at a predetermined position in a deposition apparatus, with the substrate (s) to be coated being placed in a position opposite the target (s). With typical pressures of 1.3 Pa (10^-3 torr) of gaseous oxygen and gaseous Ar, a discharge is generated between the target (s) and the substrate (s), so that the Ar or oxygen collide with the target to begin the deposition reaction, depositing as a consequence a film of composition determined on the substrate. For additional details regarding plasma spraying, see, for example, copending application having US publication number. 2004/0023 078 A1, filed on the same date as this application.

Gas atomization involves particles that are melted into a melt. A fine stream of said melt is atomized by contact with a disruptive jet of air (ie the stream is divided into fine droplets). The resulting substantially discrete and generally ellipsoidal glass particles are then collected. Melt extraction can be carried out, for example, as described in US Pat. No. 5,605,870 (Strom-Olsen et al.). Non-cumulative glass-forming techniques, using laser beam heating as described, for example, in PCT application having publication number WO 01/27046 A1, published April 4, 2001, may also be useful in the manufacture of glasses according to the present invention.

The rate of cooling is believed to affect the properties of the tempered amorphous material. For example, the glass transition temperature, density, and other properties of glass typically change with cooling rates.

Rapid cooling can also be carried out in controlled atmospheres, such as reducing, neutral or oxidizing environments, in order to maintain and / or influence the desired oxidation states, etc. during cooling. The atmosphere can also influence glass formation by influencing the crystallization kinetics of the subcooled liquid. For example, greater subcooling of Al melts has been reported.₂OR₃ no crystallization in argon atmosphere than in air atmosphere.

With regard to the manufacture of particles, for example, the resulting ceramics (eg glasses or glasses comprising ceramics) may be larger than desired. Ceramics can be, and usually are, converted into smaller pieces using crushing and / or fragmentation techniques known in the art, including roll crushing, canary milling, jaw crushing, hammer mill, ball mill grinding, jet mill grinding, impact crusher grinding and the like. In some examples, it is desirable to have two or multiple stages of grinding. For example, once the ceramic is formed (solidified), it may be in a larger than desired shape. The first stage of grinding may involve grinding these relatively large masses or "chunks" into smaller pieces. This crushing of said pieces can be carried out with a hammer mill, an impact crusher or a jaw crusher. Subsequently, these smaller pieces can then be ground to produce the desired particle size distribution. In order to produce the desired particle size distribution (sometimes referred to as grain size or grade) it may be necessary to carry out multiple stages of grinding. In general, grinding conditions are optimized to achieve the desired shape (s) and particle size distribution.

The shape of the particles may depend, in the case where the particles have been formed by crushing, for example, on the composition of the glass, the geometry in which it has been cooled and the way in which the glass has been crushed ( i.e. the grinding technique used).

Certain articles according to the invention comprising glass can be heat treated to increase or at least partially crystallize the glass (including crystallize the glass) to provide a glass ceramic. The heat treatment of certain glasses to form glass-ceramic materials is well known in the art. The heating conditions necessary to nuclear and grow glass-ceramics are well known for a number of glasses. Alternatively, one of skill in the art can determine appropriate conditions from a Time-Temperature-Transformation (TTT) study of the glass using techniques known in the art. One skilled in the art, after reading the description of the present invention, should be able to form TTT curves for glasses in accordance with the present invention and to determine the appropriate nucleation and / or crystal growth conditions to provide crystalline ceramics, glass ceramics and ceramics. comprising glass according to the present invention.

Typically, glass-ceramics are stronger than the glasses from which they are formed. Consequently, the strength of the material can be adjusted, for example, by the degree to which glass converts a phase (s) of crystalline ceramic (s). Alternatively, or in addition, the strength of the material can also be affected, for example, by the number of nucleation sites created, which can in turn be used to affect the number and, in turn, the size of the crystals of the ( s) crystalline phase (s). For additional details regarding the formation of glass-ceramics see, for example, Glass-Ceramics, PW McMillan, Academic Press, Inc., 2nd edition, 1979.

ES 2 295 396 T3

For example, during heat treatment of a glass, such as a glass containing Al₂OR₃, The₂OR₃, and ZrO₂, the formation of phases such as La₂Zr₂OR₇ and, if ZrO is present₂, ZrO₂ cubic / tetragonal and in some cases monoclinic ZrO2, at temperatures above about 900 ° C. Although it is not intended to be bound by theory, it is believed that the zirconia-related phases are the first phases of glass nucleation. For example, the phases of Al₂OR₃, REAL₃ (where Re is at least one rare earth cation), ReAlnOi₈, Re₃To the₅I heard₂, Y₃To the₅I heard₂, etc. they generally occur at temperatures above about 925 ° C. The size of the crystallites during this nucleation stage can be on the order of nanometers. For example, crystals as small as 10-15 nanometers have been observed. Higher heat treatment temperatures typically lead to growth of crystallites and progression of crystallization. For at least some embodiments, heat treatment at a temperature of about 1300 ° C for about 1 hour provides complete crystallization.

Certain ceramic articles made in accordance with the present invention contain less than 20% SiO by weight.₂ (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of SiO₂), less than 20% by weight of B₂OR₃ (or even less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of B₂OR₃) and less than 40% by weight of P₂OR₅ (or even less than 35%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 5% by weight or even zero percent by weight of P₂OR₅), with respect to the total weight of metal oxide of the ceramic.

The microstructure or the composition of a phase (glassy / amorphous / crystalline) of a material can be determined in several ways. Various information can be obtained by using, for example, light microscopy, electron microscopy, differential thermal analysis (DTA) and x-ray diffraction (XRD).

In cases where you use light microscopy, an amorphous material is typically predominantly transparent due to the lack of light scattering centers, such as crystal boundaries, while a crystalline material exhibits a crystalline structure and is opaque due to effects. light scattering.

In cases where DTA is used, the material is classified as amorphous when the corresponding DTA curve of the material contains an exothermic crystallization event (T_x). If the same curve also contains an endothermic event (T_g) at a temperature lower than T_x, it is considered to consist of a vitreous phase. If the DTA curve of the material does not contain such events, it is considered to contain crystalline phases.

Differential thermal analysis can be carried out using the following method. DTA analysis can be performed (using equipment such as from Netzsch Instruments, Selb, Germany, under the trademark "NETZSCH STA 409 DTA / TGA") using a -140 + 170 mesh size fraction (ie, the fraction collected between 105 micron aperture size and 90 micron aperture size sieves). A quantity of each sieved sample (typically approximately 400 milligrams (mg)) is placed in a 100 microliter Al2O3 sample holder. Each sample is heated in a static air atmosphere at a rate of 10 ° C / minute, from room temperature (approximately 25 ° C) to a temperature of 1100 ° C.

In cases where x-ray diffraction is used by the powder method (using an x-ray diffractometer such as that of the trademark "PHILLIPS XRG 3100" from Phillips, Mahwah, NJ, with copper K radiation α1 of 1.54050 Angstrom), The phases present in a material can be determined by comparing the peaks present in the XRD diffractogram of the crystallized material with the XRD patterns of crystalline phases that are provided in the JCPDS (Joint Committee on Powder Diffraction Standards) databases, published by the International Center for Diffraction Data. Additionally, XRD can be used qualitatively to determine phase types. The presence of a broad peak of diffuse intensity is considered an indication of the amorphous nature of a material. The existence in the same diffractogram of a broad peak and well-defined peaks is considered as an indication of the existence of crystalline phases within an amorphous matrix. The initially formed amorphous or ceramic material (including pre-crystallization glass) can be of a larger size than desired. The amorphous or ceramic material can be converted into smaller pieces by using crushing and / or fragmentation techniques known in the art, including roll crushing, canary milling, jaw crushing, hammer milling. , ball milling, jet milling, impact crushing and the like. In some examples, it is desirable to have two or multiple stages of grinding. For example, once the ceramic is formed (solidified), it may be in a larger than desired shape. The first stage of grinding may involve grinding these relatively large masses or "chunks" into smaller pieces. This crushing of said pieces can be carried out with a hammer mill, an impact crusher or a jaw crusher. Subsequently, these smaller pieces can then be ground to produce the desired particle size distribution. In order to produce the desired particle size distribution (sometimes referred to as grain size or grade) it may be necessary to carry out multiple stages of grinding. In general, grinding conditions are optimized to achieve the desired shape (s) and particle size distribution. The resulting particles that are not of the desired size can be re-ground if they are too large or can be "recycled" and used as a starting material for remelting if they are too small.

The shape of the particles may depend on, for example, the composition and / or microstructure of the ceramic, the geometry in which it has been cooled and the way in which the ceramic has been ground (i.e., the grinding technique used). In general, when a "blocky" shape is preferred, more energy must be used to achieve this shape.

ES 2 295 396 T3

Conversely, when a "fine" shape is preferred, less energy must be used to achieve this shape. The grinding technique can also be changed to achieve different desired shapes. For some particles an average aspect ratio ranging from 1: 1 to 5: 1 is typically desired, and in some embodiments from 1.25: 1 to 3: 1 or even 1.5: 1 to 2.5 :1.

Ceramic articles (including glass-ceramics) manufactured in accordance with the present invention may comprise at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70 .75, 80, 85, 90, 95, 97, 98, 99, or even 100 percent by volume of crystallites, so that the crystallites have an average size of less than 1 micron. In another aspect, ceramic articles (including glass-ceramics) made in accordance with the present invention may comprise less than at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 , 60, 65, 70, 75, 80, 85, 90, 95, 97, 98, 99 or even 100 percent by volume of crystallites, so that the crystallites have an average size of less than 0.5 microns. In another aspect, the ceramics (including glass-ceramics) according to the present invention comprise less than at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 97, 98, 99 or even 100 percent by volume of crystallites, so that the crystallites have an average size of less than 0.3 microns. In another aspect, ceramic articles (including glass-ceramics) made in accordance with the present invention may comprise less than at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 , 60, 65, 70, 75, 80, 85, 90, 95, 97, 98, 99 or even 100 percent by volume of crystallites, so that the crystallites have an average size of less than 0.15 microns. In another aspect, ceramic articles (including glass-ceramics) made in accordance with the present invention may be free of at least one aspect of a eutectic microstructure (ie, free of colonies and lamellar structure) or of a non-cellular microstructure.

In another aspect, certain ceramic articles made in accordance with the present invention may comprise, for example, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or even 100 percent by volume of glass. In another aspect, certain ceramic articles made in accordance with the present invention may comprise, for example, 100 or at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95,

97, 98, 99 or even 100 percent by volume of crystalline ceramic.

Certain articles made in accordance with the present invention comprise glass comprising CaO and Al₂OR₃, wherein at least 80 (85, 90, 95, 97, 98, 99 or even 100) weight percent of the glass collectively comprises CaO and Al₂OR₃, with respect to the total weight of the glass.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising glass (eg, at least 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65 , 70, 75, 80, 85, 90, 95, 97, 98, 99 or even 100 percent by volume of glass), glass comprising CaO and Al₂OR₃, wherein at least 80 (85, 90, 95, 97, 98, 99, or even 100) percent by weight of the glass collectively comprises the CaO and Al₂OR₃, with respect to the total weight of the glass.

In another aspect, certain articles made in accordance with the present invention provide glass-ceramics comprising CaO and Al₂OR₃, wherein at least 80 (85, 90, 95, 97, 98, 99 or even 100) weight percent of the glass-ceramic collectively comprises CaO and Al2O3, relative to the total weight of the glass-ceramic. The glass-ceramic can comprise, for example, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 or 95 percent by volume of glass. The glass-ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10 or 5 percent by volume of crystalline ceramic.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising crystalline ceramic (eg, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 97,

98, 99 or even 100 volume percent crystalline ceramic), the crystalline ceramic comprising CaO and Al₂OR₃, wherein at least 80 (85, 90, 95, 97, 98, 99 or even 100) weight percent of the crystalline ceramic collectively comprises CaO and Al2O3, relative to the total weight of the crystalline ceramic. The ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 3, 2 or 1 percent by volume of glass.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising crystalline ceramic (e.g., at least 1,2,3,5,10,15,20,25, 30, 35,40,45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 97, 98, 99 or even 100 percent by volume of crystalline ceramics), the crystalline ceramics comprising CaO and Al₂OR₃, in which at least 80 (85, 90, 95,97,98, 99 or even 100) percent by weight of the ceramic collectively comprises CaO and Al₂OR₃, with respect to the total weight of the ceramic. The ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 3, 2 or 1 percent by volume of glass.

Certain articles made in accordance with the present invention comprise glass comprising CaO, Al2O3 and ZrO2, wherein at least 80 (85, 90, 95, 97, 98, 99 or even 100) weight percent of the glass collectively comprises the CaO, Al2O3 and ZrO2, with respect to the total weight of the glass.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising glass (eg, at least 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65 , 70, 75, 80, 85, 90, 95, 97, 98, 99 or even 100 percent by volume of glass), glass comprising CaO, Al2O3 and ZrO2, in which at least 80 (85, 90, 95 , 97, 98, 99 or even 100) weight percent of the glass collectively comprises CaO, Al₂OR₃ and the ZrO₂ with respect to the total weight of the glass.

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In another aspect, certain articles made in accordance with the present invention provide glass-ceramics comprising CaO, Al₂OR₃ and ZrO₂, in which at least 80 (85, 90, 95, 97, 98, 99 or even 100) percent by weight of the glass-ceramic collectively comprises CaO, Al₂OR₃ and the ZrO₂, with respect to the total weight of the glass-ceramic. The glass-ceramic can comprise, for example, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 or 95 percent by volume of glass. The glass-ceramic can comprise, for example, at least 99, 98,

97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, or 5 percent by volume of crystalline ceramic.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising crystalline ceramic (eg, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 97,

98, 99 or even 100 volume percent crystalline ceramic), the crystalline ceramic comprising CaO, Al₂OR₃and ZrO₂, wherein at least 80 (85, 90, 95, 97, 98, 99, or even 100) percent by weight of the crystalline ceramic collectively comprises CaO, Al₂ OR₃and the zrO₂, with respect to the total weight of the crystalline ceramic. The ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 3, 2 or 1 percent by volume of glass.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising crystalline ceramic (eg, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 97, 98, 99 or even percent by volume of crystalline ceramics), the ceramics comprising CaO, Al₂OR₃ and ZrO₂, in which at least 80 (85, 90, 95, 97, 98, 99 or even 100) percent by weight of the ceramic collectively comprises CaO, Al₂OR₃ and the ZrO₂, with respect to the total weight of the ceramic. The ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 3, 2 or 1 percent by volume of glass.

Certain articles made in accordance with the present invention comprise glass comprising BaO and TiO2, wherein at least 80 (85, 90, 95, 97, 98, 99 or even 100) weight percent of the glass collectively comprises BaO and TiO2, with respect to the total weight of the glass.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising glass (eg, at least 5, 10, 15, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60 , 65, 70, 75, 80, 85, 90, 95, 97, 98, 99 or even 100 percent by volume of glass), glass comprising BaO and TiO₂, wherein at least 80 (85, 90, 95, 97, 98, 99 or even 100) weight percent of the glass collectively comprises the BaO and TiO₂, with respect to the total weight of the glass.

In another aspect, certain articles made in accordance with the present invention provide glass-ceramics comprising BaO and TiO.₂, wherein at least 80 (85, 90, 95, 97, 98, 99 or even 100) percent by weight of the glass-ceramic collectively comprises BaO and TiO2, relative to the total weight of the glass-ceramic. The glass-ceramic can comprise, for example, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 or 95 percent by volume of glass. The glass-ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10 or 5 percent by volume of crystalline ceramic.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising crystalline ceramic (eg, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 97, 98, 99 or even 100 volume percent crystalline ceramic), the crystalline ceramic comprising BaO and TiO₂, wherein at least 80 (85, 90, 95, 97, 98, 99, or even 100) percent by weight of the crystalline ceramic collectively comprises BaO and TiO2, relative to the total weight of the crystalline ceramic. The ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 3, 2 or 1 percent by volume of glass.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising crystalline ceramic (eg, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 97, 98, 99 or even 100 volume percent crystalline ceramic), the crystalline ceramic comprising BaO and TiO₂, wherein at least 80 (85, 90, 95, 97, 98, 99, or even 100) percent by weight of the crystalline ceramic collectively comprises BaO and TiO2, relative to the total weight of the crystalline ceramic. The ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 3, 2 or 1 percent by volume of glass.

Certain articles made in accordance with the present invention comprise glass comprising La2O3 and TiO2, wherein at least 80 (85, 90, 95, 97, 98, 99 or even 100) percent by weight of the glass collectively comprises La₂OR₃ and TiO₂, with respect to the total weight of the glass.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising glass (eg, at least 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65 , 70, 75, 80, 85, 90, 95, 97, 98, 99 or even 100 percent by volume of glass), glass comprising La2O3 and TiO2, in which at least 80 (85, 90, 95, 97 98, 99 or even 100) percent by weight of the glass collectively comprises the La₂OR₃ and TiO₂, with respect to the total weight of the glass.

In another aspect, certain articles made in accordance with the present invention provide glass-ceramics comprising La₂OR₃ and uncle₂, in which at least 80 (85, 90, 95, 97, 98, 99 or even 100) percent by weight of the glass ceramic

ES 2 295 396 T3 collectively comprises the La₂OR₃ and TiO₂, with respect to the total weight of the glass-ceramic. The glass-ceramic can comprise, for example, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 or 95 percent by volume of glass. The glass-ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10 or 5 percent by volume of crystalline ceramic.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising crystalline ceramic (eg, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 97, 98, 99 or even 100 percent by volume of crystalline ceramics), the crystalline ceramics comprising La₂OR₃ and uncle₂, wherein at least 80 (85, 90, 95, 97, 98, 99 or even 100) weight percent of the crystalline ceramic collectively comprises La2O3 and TiO2, relative to the total weight of the crystalline ceramic. The ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 3, 2 or 1 percent by volume of glass.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising crystalline ceramic (eg, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 97, 98, 99 or even percent by volume of crystalline ceramics), ceramics comprising La2O3 and TiO2, in which at least 80 ( 85, 90, 95, 97, 98, 99 or even 100) percent by weight of the ceramic collectively comprises the La₂OR₃and TiO₂, with respect to the total weight of the ceramic. The ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 3, 2 or 1 percent by volume of glass.

Certain articles made in accordance with the present invention comprise glass comprising REO and Al2O3, wherein at least 80 (85, 90, 95, 97.98, 99 or even 100) weight percent of the glass collectively comprises REO and Al₂OR₃, with respect to the total weight of the glass.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising glass (eg, at least 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65 , 70, 75, 80, 85, 90, 95, 97, 98, 99 or even 100 percent by volume of glass), comprising REO glass and Al2O3, in which at least 80 (85, 90, 95, 97 98, 99 or even 100) weight percent of the glass collectively comprises REO and Al₂OR₃, with respect to the total weight of the glass.

In another aspect, certain articles made in accordance with the present invention provide glass ceramics comprising REO and Al₂OR₃, wherein at least 80 (85, 90, 95, 97, 98, 99 or even 100) weight percent of the glass-ceramic collectively comprises REO and Al2O3, relative to the total weight of the glass-ceramic. The glass-ceramic can comprise, for example, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 or 95 percent by volume of glass. The glass-ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10 or 5 percent by volume of crystalline ceramic.

In another aspect, the present invention provides glass-ceramics comprising REO and Al2O3, wherein, for example, the glass-ceramic exhibits a microstructure comprising crystallites having an average crystallite size of less than 1 micron (typically, less than 500 nanometers, even less than 300, 200 or 150 nanometers; and, in some embodiments, less than 100, 75, 50, 25, or 20 nanometers) and that is free of at least one aspect of the eutectic microstructure or of a non-cellular microstructure. The glass-ceramic can comprise, for example, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90.95 percent by volume glass. The glass-ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10 or 5 percent by volume of crystalline ceramic.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising crystalline ceramic (eg, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 97, 98, 99 or even 100 volume percent crystalline ceramics), comprising REO and Al crystalline ceramics₂OR₃, wherein at least 80 (85, 90, 95, 97, 98, 99 or even 100) percent by weight of the crystalline ceramic collectively comprises the REO and the Al₂OR₃, with respect to the total weight of the crystalline ceramic. The ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 3, 2 or 1 percent by volume of glass.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising crystalline ceramic (eg, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 97, 98, 99 or even 100 volume percent crystalline ceramics), comprising REO and Al crystalline ceramics₂OR₃, wherein at least 80 (85, 90, 95, 97, 98, 99 or even 100) percent by weight of the ceramic collectively comprises the REO and the Al2O3, relative to the total weight of the ceramic. The ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 3, 2 or 1 percent by volume of glass.

Certain articles made in accordance with the present invention comprise glass comprising REO and Al2O3, wherein at least 80 (85, 90, 95, 97.98, 99 or even 100) weight percent of the glass collectively comprises REO and Al₂OR₃, with respect to the total weight of the glass.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising glass (eg, at least 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65 , 70, 75, 80, 85, 90, 95, 97, 98, 99 or even 100

ES 2 295 396 T3 percent by volume of glass), comprising REO glass, Al₂OR₃ and ZrO₂, wherein at least 80 (85, 90, 95, 97, 98.99, or even 100) percent by weight of the glass collectively comprises the REO, the Al₂OR₃ and the ZrO₂ with respect to the total weight of the glass.

In another aspect, certain articles made in accordance with the present invention provide glass-ceramics comprising REO, Al₂OR₃ and ZrO₂, wherein at least 80 (85, 90, 95, 97, 98, 99, or even 100) percent by weight of the glass-ceramic collectively comprises the REO, the Al₂OR₃ and the ZrO₂, with respect to the total weight of the glass-ceramic. The glass-ceramic can comprise, for example, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 or 95 percent by volume of glass. The glass-ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10 or 5 percent by volume of crystalline ceramic.

In another aspect, the present invention provides glass-ceramics comprising REO, Al2O3, and ZrO2, wherein the glass-ceramic (a) exhibits a microstructure comprising crystallites having an average crystallite size of less than 1 micron (typically, less than 500 nanometers). , even less than 300, 200 or 150 nanometers; and, in some embodiments, less than 100, 75, 50, 25, or 20 nanometers) and (b) is free of at least one aspect of the eutectic microstructure or of a non-cellular microstructure. The glass-ceramic can comprise, for example, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90.95 percent by volume glass. The glass-ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10 or 5 percent by volume of crystalline ceramic.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising crystalline ceramic (eg, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95,

97, 98, 99 or even 100 percent by volume crystalline ceramic), comprising REO, Al₂OR₃ and ZrO₂, in which at least 80 (85,90,95, 97, 98, 99 or even 100) percent by weight of the crystalline ceramic collectively comprises REO, Al2O3 and zrO2, relative to the total weight of the ceramic crystalline. The ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 3, 2 or 1 percent by volume of glass.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising crystalline ceramic (eg, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 97,

98, 99 or even percent by volume of crystalline ceramics), including REO ceramics, Al₂OR₃ and ZrO₂, wherein at least 80 (85, 90, 95, 97, 98, 99 or even 100) weight percent of the ceramic collectively comprises REO, Al2O3 and ZrO2, relative to the total weight of the ceramic. The ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 3, 2 or 1 percent by volume of glass.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising glass (eg, at least 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65 , 70, 75, 80, 85, 90, 95, 97, 98, 99 or even 100 percent by volume of glass), glass comprising REO, Al₂OR₃, ZrO₂ and SiO₂, wherein at least 80 (85, 90, 95, 97, 98, 99 or even 100) percent by weight of the glass collectively comprises the REO, the Al₂OR₃ and the ZrO₂, with respect to the total weight of the glass.

In another aspect, certain articles made in accordance with the present invention provide glass-ceramics comprising REO, Al₂OR₃, ZrO₂ and SiO₂, wherein at least 80 (85, 90, 95, 97, 98, 99, or even 100) percent by weight of the glass-ceramic collectively comprises the REO, the Al₂ OR₃ and the ZrO₂, with respect to the total weight of the glass-ceramic. The glass-ceramic can comprise, for example, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 or 95 percent by volume of glass. The glass-ceramic can comprise, for example, at least 99, 98,

97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, or 5 percent by volume of crystalline ceramic.

In another aspect, the present invention provides glass-ceramics comprising REO, Al₂OR₃, ZrO₂ and SiO₂, wherein the glass-ceramic (a) exhibits a microstructure comprising crystallites having an average crystallite size of less than 1 micron (typically less than 500 nanometers, even less than 300, 200, or 150 nanometers; and, in some ways performance, less than 100, 75, 50, 25, or 20 nanometers) and (b) is free from at least one aspect of the eutectic microstructure or a non-cellular microstructure. The glass-ceramic can comprise, for example, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90.95 percent by volume glass. The glass-ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10 or 5 percent by volume of crystalline ceramic.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising crystalline ceramic (eg, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 97,

98, 99 or even 100 percent by volume crystalline ceramic), comprising REO, Al₂OR₃, ZrO₂ and SiO₂, wherein at least 80 (85, 90, 95, 97, 98, 99 or even 100) weight percent of the crystalline ceramic collectively comprises REO, Al2O3, zrO2, and SiO2, relative to total weight of crystalline ceramics. The ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 3, 2 or 1 percent by volume of glass.

In another aspect, certain articles made in accordance with the present invention provide a ceramic comprising crystalline ceramic (eg, at least 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 97,

ES 2 295 396 T3

98, 99 or even percent by volume of crystalline ceramics), comprising REO, Al2O3 and ZrO2 ceramics, in which at least 80 (85, 90, 95, 97, 98, 99 or even 100) percent by weight of ceramics collectively comprise REO, Al2O3, ZrO2 and SiO2, relative to the total weight of the ceramic. The ceramic can comprise, for example, at least 99, 98, 97, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 3, 2 or 1 percent by volume of glass.

Crystalline phases that may be present in ceramics according to the present invention include alumina (eg, alpha and transition aluminas), BaO, CaO, Cr₂OR₃, CoO, Fe₂OR₃, GeO₂, HfO₂, Li₂O, MgO, MnO, NiO, Na₂O, P₂OR₅, REO, Sc₂OR₃, Yes₂, SrO, TeO₂, Uncle₂, V₂OR₃, Y₂OR₃, ZnO, ZrO₂, “Complex metal oxides” (including “complex Al₂OR₃-metal oxide ”(eg, the complex Al₂OR₃-CONVICT))_; and combinations of the above.

Additional details can be found regarding ceramics comprising Al2O3, at least one between REO and Y₂OR₃, and at least one of ZrO₂ and HfO₂, including details of manufacture, use and properties, in applications having US serial numbers 09 / 922,527, 09 / 922,528 and 09 / 922,530, filed August 2, 2001; and in US Publications n^you 2003-0115805-A1, 2003-0110707-A1, 2003-O110709-A1, 2003-0126802-A1, 2003-0145525-A1, 2003-0126804-A1, 2004-0023078-A1 and 2004-0020245-A1 (Certificates of Presentation (Attorney Docket) n^you 56931US005, 56931US006, 56931US007, 56931US008, 56931US009, 56931US010, 57980US002 and 57981US002) filed on the same date as the present application.

Typically, and desirably, the (true) density, sometimes referred to as specific gravity, of a ceramic according to the present invention is typically at least 70% of the theoretical density. More desirably, the (true) density of a ceramic according to the present invention is at least 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5% or 100% of the theoretical density.

Examples of articles according to the present invention include kitchen utensils (eg, plates), dental supports and reinforced fibers, inserts for cutting tools, abrasive materials, and structural components of gas engines (eg, valves and fittings). bearings). Other articles include those that have a ceramic protective coating on the outer surface of a body or other substrate. Furthermore, for example, a ceramic according to the invention can be used as a matrix material. For example, the ceramics according to the invention can be used as a binder for ceramic materials and the like, such as diamond, cubic-BN, Al₂OR₃, ZrO₂, Yes₃N₄ and SiC. Examples of useful articles include materials such as composite substrate coatings, cutting tool inserts, abrasive agglomerates, and bonded abrasive articles, such as in vitrified machinery. The ceramics according to the present invention can be used as binders and can, for example, increase the modulus, heat resistance, wear resistance and / or strength of the composite article.

The invention is summarized in the following points:

(TO) . A method of manufacturing a glass article comprising:

providing a substrate that includes an outer surface;

providing at least a first glass, such that the first glass comprises at least two different metal oxides, in which the first glass has a Tg and a Tx, and in which the difference between the Tg and the Tx of the first glass is at least 5K, glass containing less than 20% by weight of SiO2, less than 20% by weight of B₂OR₃ and less than 40% by weight of P₂OR₅;

heating the first glass above the Tg to a temperature such that at least a part of the glass wets at least a part of the outer surface of the substrate when in contact with it; and cooling the glass to provide an article comprising a ceramic comprising the glass bonded to at least a portion of the outer surface of the substrate.

(B). The method according to point (A), in which the difference between Tg and Tx is at least 25K.

(C). The method according to point (B), in which the glass has a Ti and in which the ratio of T_g a Ti is at least 0.5.

(D). The method according to item (C), wherein the first glass comprises less than 40 weight percent of the SiO glass₂, B₂OR₃ And p₂OR₅ collectively, with respect to the total weight of the glass.

(E). The method according to point (C), in which the glass is a REO-Al2O3 glass.

(F). The method according to item (E), wherein the glass comprises at least 80 weight percent Al₂OR₃ and REO collectively, with respect to the total weight of the glass.

(G). The method according to point (A), in which the glass is a REO-Al2O3 -ZrO2 glass.

(H). The method according to item (G), wherein the glass comprises at least 80 weight percent Al2O3, REO and ZrO₂ collectively, with respect to the total weight of the glass.

ES 2 295 396 T3 (I) The method according to item (A), wherein the article comprises glass and wherein the method further comprises a heat treatment of the glass to provide a glass-ceramic.

(J). An article manufactured according to the method of point (I).

(K). The method according to point (A), in which the difference between Tg and Tx is at least 35K.

(L). An article manufactured according to the method of item (A).

(M). A method of manufacturing a glass article comprising:

providing a substrate that includes an outer surface;

providing at least a first plurality of particles comprising glass, such that the glass comprises at least two different metal oxides, in which the glass has a Tg and a Tx, and in which the difference between the Tg and the Tx of the glass is at least 5K, the glass containing less than 20% by weight SiO₂, less than 20% by weight of B₂OR₃ and less than 40% by weight of P₂OR₅;

heating the first glass above the Tg to a temperature such that at least a portion of the glass of the first plurality of particles wets at least a portion of the outer surface of the substrate; and cooling the glass to provide an article comprising a ceramic comprising the glass bonded to at least a portion of the outer surface of the substrate.

(N). The method according to point (M), in which the difference between Tg and Tx is at least 25K.

(O). The method according to point (N), in which the glass has a Ti and in which the ratio of T_g a Ti is at least 0.5.

(P). The method according to point (O), wherein the glass comprises less than 40 weight percent SiO₂, B₂OR₃And p₂OR₅ collectively, with respect to the total weight of the glass.

(Q). The method according to point (O), where the glass is REO-Al glass₂OR₃.

(R). The method according to item (Q), wherein the glass comprises at least 80 weight percent Al₂OR₃ and REO collectively, with respect to the total weight of the glass.

(S). The method according to point (M), in which the glass is a REO-Al2O3 -ZrO2 glass.

(T). The method according to item (S), wherein the glass comprises at least 80 weight percent Al₂OR₃, REO and ZrO2 collectively, with respect to the total weight of the glass.

(OR) . The method according to item (M), wherein the article comprises glass and wherein the method further comprises a heat treatment of the glass to provide a glass-ceramic.

(V). An item made according to the method in point (U).

(W). The method according to point (M), where the difference between Tg and Tx is at least 35K.

(X). An article manufactured according to the method of point (M).

(Aa). A method of manufacturing an article comprising:

providing at least a first glass and a second glass, such that the first glass comprises at least two different metal oxides, in which the first glass has a Tgi and a Txi, and in which the difference between the Tgi and the Txi is at least 5K, the first glass containing less than 20% by weight SiO₂, less than 20% by weight of B₂OR₃ and less than 40% by weight of P₂OR₅;

heat the first and second glasses above at least T_g1with at least the first glass coalescing with the second glass to provide the article.

(Ab). The method according to point (Aa), in which the difference between Tg1 and Tx1 is at least 25K.

(Ac). The method according to point (Ab), in which the glass has a Ti1 and in which the ratio of Tg1 to Ti1 is at least 0.5.

(Ad). The method according to point (Ac), wherein the first glass comprises less than 40 percent by weight of the SiO glass₂, B₂OR₃ And p₂OR₅ collectively, with respect to the total weight of the glass.

ES 2 295 396 T3 (Ae). The method according to point (Ad), where the glass is REO-Al glass₂OR₃.

(Af). The method according to point (Ae), in which the glass comprises at least 80 percent by weight of Al2O3 and REO collectively, with respect to the total weight of the glass.

(Ag). The method according to item (Aa), in which the glass is a REO-Al2O3-ZrO2 glass.

(Ah). The method according to point (Ag), wherein the glass comprises at least 80 weight percent Al₂OR₃, REO and ZrO₂ collectively, with respect to the total weight of the glass.

(Ai). The method according to item (Aa), wherein the article comprises glass and wherein the method further comprises a heat treatment of the glass to provide a glass-ceramic.

(Aj). An article manufactured according to the method of item (Ai).

(Ak). The method according to point (Aa), in which the difference between the T_g1 and the T_x1 is at least 35K.

(To the). An article manufactured according to the method of item (Aa).

(A.M). A method of manufacturing an article comprising:

providing at least a first glass and a second glass, such that the first glass comprises at least two different metal oxides, wherein the first glass has a T_g1 and a T_x1, and in which the difference between the T_g1 and the T_x1 is at least 5K, the first glass containing less than 20% by weight SiO₂, less than 20% by weight of B₂OR₃ and less than 40% by weight of P₂OR₅, and in which the second glass comprises at least two different metal oxides, in which the second glass has a T_g2 and a T_x2, and in which the difference between the T_g2 and the 'T- is at least 5K, with the second glass containing less than 20% by weight of SiO₂, less than 20% by weight of B₂OR₃ and less than 40% by weight of P₂OR₅;

heat the glasses above the highest temperature of T_g1 or T_g2 and coalescing the first and second glasses to provide the article.

(An). The method according to point (Am), in which the difference between each T_g1 and T_x1 and between each T_g2 and T_x2 is at least 25K.

(Year). The method according to the point (Am), in which the ratio of each T_g1 to T_x1 and of each T_g2 to T_x2 is at least 0.5K.

(Ap). The method according to item (Ao), wherein both first glass and second glass comprise less than 40 weight percent SiO₂, B₂OR₃ And p₂OR₅ collectively, with respect to the total weight of the glass.

(Aq). The method according to point (Ao), in which the glass is a REO-Al2O3 glass.

(Ar). The method according to point (Aq), in which the glass comprises at least 80 percent by weight of Al2O3 and REO collectively, with respect to the total weight of the glass.

(Ace). The method according to point (Am), where the glass is REO-Al glass₂OR₃-ZrO₂.

(At). The method according to item (As), wherein the glass comprises at least 80 weight percent Al2O3, REO and ZrO₂ collectively, with respect to the total weight of the glass.

(Au). The method according to item (Am), wherein the article comprises glass and wherein the method further comprises a heat treatment of the glass to provide a glass-ceramic.

(Av). An article manufactured according to the method of the point (Au).

(Aw). The method according to the point (Am), in which the difference between the T_g and the T_x is at least 35K.

(Ax). The method according to point (Am), in which the first and second glasses have the same compositions.

(Oh). The method according to point (Am), in which the first and second glasses have different compositions.

(Az). An article manufactured according to the method of point (Am).

(Ba). A method of manufacturing an article comprising:

providing at least a first plurality of particles comprising glass, such that the glass comprises at least two different metal oxides, in which the glass has a Tg and a Tx, and in which the difference between the Tg and the Tx of the glass is at least 5K, the glass containing less than 20% by weight SiO₂, less than 20% by weight of B₂OR₃ and less than 40% by weight of P₂OR₅;

ES 2 295 396 T3 heating the glass above the Tg and coalescing at least a portion of the first plurality of particles to provide the article.

(Bb). The method according to point (Ba), in which the difference between Tg and Tx is at least 25K.

(Bc). The method according to point (Bb), in which the glass has a Ti and in which the ratio of Tg to Ti is at least 0.5.

(Bd). The method according to item (Bc), wherein the glass comprises less than 40 weight percent SiO2, B₂OR₃ And p₂OR₅ collectively, with respect to the total weight of the glass.

(Be). The method according to point (Bc), in which the glass is a REO-Al2O3 glass.

(Bf). The method according to point (Be), in which the glass comprises at least 80 percent by weight of Al2O3 and REO collectively, with respect to the total weight of the glass.

(Bg). The method according to point (Bc), in which the glass is a REO-Al2O3-ZrO2 glass.

(Bh). The method according to item (Bg), wherein the glass comprises at least 80 weight percent Al₂OR₃, REO and ZrO₂ collectively, with respect to the total weight of the glass.

(Bi). The method according to item (Bc), wherein the article comprises glass and wherein the method further comprises a heat treatment of the glass to provide a glass-ceramic.

(Bj). An article manufactured according to the method of point (Bi).

(Bk). The method according to point (Bc), in which the difference between the T_g and the T_x is at least 35K.

(Bl). An article manufactured according to the method of item (Bc).

The advantages and embodiments of this invention are further illustrated by the following examples, although the particular materials and amounts thereof set forth in these examples, as well as other conditions and details, should not be understood to unduly limit this invention. All concentrations in parts and percentages are by weight, unless otherwise indicated. Unless stated otherwise, all examples contained non-significant amounts of SiO₂, B₂OR₃, P₂OR₅, GeO₂, TeO₂, As₂OR₃ and V₂OR₅.

Examples

Example 1

27.5 grams of alumina particles (obtained from Condea Vista, Tucson, AZ, under the trade name "APA-0.5"), 22.5 grams of calcium oxide particles (obtained from Alfa Aesar, Ward Hill, MA) and 90 grams of isopropyl alcohol. Approximately 200 grams of medium mill zirconia (obtained from Tosoh Ceramics, Division of Bound Brook, NJ, under the trade name "YTZ") was added to the flask and the mixture was ground at 120 revolutions per minute (rpm) for 24 hours. After grinding, the middle grind was separated and the flowable paste was poured into a glass capsule ("PYREX"), where it was dried using a blowtorch. The dry mix was pulverized into a pestle mortar and sieved through a 70mesh sieve (212 micron aperture size).

After pulverizing and sieving, some of the particles were fed into a hydrogen / oxygen flame torch. The torch used to melt the particles, thus generating molten glass beads, was a Bethlehem PM2D model B tabletop burner , obtained from Bethlehem Apparatus Co., Hellertown, PA, which releases hydrogen and oxygen to the following speeds. For the inner ring, the hydrogen flow rate was 8 standard liters per minute (SLPM) and the oxygen flow rate was 3 SLPM. For the outer ring, the hydrogen flow rate was 23 SLPM and the oxygen flow rate was 9.8 SLPM. The dry and properly sized particles were fed directly into the torch flame, where they were melted, and transported to a sloped stainless steel surface (approximately 51 centimeters (cm) (20 inches) wide with an angle of inclination 45 degrees) above which cold water ran (about 8 liters / minute) to form the beads.

Examples 2-9

The glass beads of Examples 2-9 were prepared as described in Example 1, except that the starting materials and the amounts of the starting materials used are specified in Table 1, below, and that the milling of the starting materials was carried out in 90 mL (milliliters) of isopropyl alcohol with 200 grams of medium zirconia (obtained from Tosoh Ceramics, Division of Bound Brook, NJ, tradename "YTZ") at 120 rpm for 24 hours. The sources used for the starting materials are listed below in Table 2.

ES 2 295 396 T3

TABLE 1

<td>Example</td><td>Percentage by weight of the components</td><td>Quantities per batch, g</td>

<td> 2</td><td>CaO: 36 AI₂OR₃: 44 ZrO₂. 20</td><td>CaO: 18 AI₂OR₃: 22 ZrO₂: 10</td>

<td> 3</td><td>The₂OR₃: Four. Five Uncle₂: 55</td><td>The₂OR₃: 22.5 Uncle₂: 27,5</td>

<td> 4</td><td>The₂OR₃: 36 Uncle₂: 44 ZrO₂: 20</td><td>The₂OR₃: 18 Uncle₂: 22 ZrO₂: 10</td>

<td> 5</td><td>BaO: 47.5 Uncle₂: 52,5</td><td>BaO: 23.75 Uncle₂: 26,25</td>

<td> 6</td><td>The₂OR₃: 48 AI₂OR₃: 52</td><td>The₂OR₃: 24 AI₂OR₃: 26</td>

<td> 7</td><td>The₂OR₃: 40.9 AI₂OR₃: 40.98 ZrO₂: 18,12</td><td>The₂OR₃: 20.45 AI₂OR₃: 20.49 ZrO₂: 9,06</td>

<td> 8</td><td>The₂OR₃: 43 AI₂OR₃: 32 ZrO₂: 12 Yes₂: 13</td><td>The₂OR₃: 21.5 AI₂OR₃: 16 ZrO₂: 6 Yes₂: 6.5</td>

<td> 9</td><td>SrO: 22.95 AI₂OR₃: 62.05 ZrO₂: 15</td><td>SrO: 11.47 AI₂OR₃: 31.25 ZrO₂: 7,5</td>

TABLE 2

<td>Starting material</td><td>Source</td>

<td>Alumina (AI₂OR₃) in particles</td><td>Obtained from Condea Vista, Tucson, AZ, under the trade name APA-0.5</td>

<td>Calcium oxide (CaO) particulate</td><td>Obtained from Alfa Aesar Firm, Ward Hill, MA</td>

<td>Lanthanum oxide (La₂OR₃) in particles</td><td>Obtained from Molycorp Inc., Mountain Pass, CA</td>

<td>Silica (SiO₂) in particles</td><td>Obtained from Alfa Aesar firm</td>

<td>Barium oxide (BaO) particulate</td><td>Obtained from Aldrich Chemical Co.</td>

<td>Titanium dioxide (TiO₂) in particles</td><td>Obtained from Kemira Inc., Savannah, GA</td>

<td>Strontium oxide (SrO) particulate</td><td>Obtained from Alfa Aesar firm</td>

<td>Ytria Stabilized Zirconium Oxide (Y-PSZ) Particulate</td><td>Obtained from Zirconia Sales, Inc. of Marietta. GA, under the trade name HSY-3 "</td>

ES 2 295 396 T3

Various properties / characteristics of some materials from Examples 1-9 were measured as follows. X-ray diffraction by the powder method (carried out on an x-ray diffractometer (obtained from PHILLIPS, Mahwah, NJ, under the trade name "PHILLIPS XRG 3100") with copper radiation K α1 of 1 , 54050 Angstrom)) was used to qualitatively measure the phases present in the example materials. The presence of a broad peak of diffuse intensity was considered as an indication of the amorphous nature of a material. The existence in the same diffractogram of a broad peak and well-defined peaks was considered as an indication of the existence of crystalline matter within an amorphous matrix. The phases detected in various examples are listed in Table 3, which follows.

TABLE 3

<td>Example</td><td>Phases detected via x-ray diffraction</td><td>Colour</td><td>T₀, 'C</td><td>T_X. ° C</td><td>Temp. hot compression. ° C</td>

<td> 1</td><td>Amorphous *</td><td>Of course</td><td> 850</td><td> 987</td><td> 985</td>

<td> 2</td><td>Amorphous *</td><td>Of course</td><td> 851</td><td> 977</td><td> 975</td>

<td> 3</td><td>Amorphous *</td><td>Of course</td><td> 799</td><td> 875</td><td> 880</td>

<td> 4</td><td>Amorphous *</td><td>Of course</td><td> 821</td><td> 876</td><td> 880</td>

<td> 5</td><td>Amorphous *</td><td>Of course</td><td> 724</td><td> 760</td><td> 815</td>

<td> 6</td><td>Amorphous *</td><td>Of course</td><td> 855</td><td> 920</td><td> 970</td>

<td> 7</td><td>Amorphous *</td><td>Of course</td><td> 839</td><td> 932</td><td> 965</td>

<td>β</td><td>Amorphous *</td><td>Of course</td><td> 836</td><td> 1002</td><td> 970</td>

<td> 9</td><td>Amorphous *</td><td>Of course</td><td> 875</td><td> 934</td><td> 975</td>

glass, since the example has a T_or

To perform differential thermal analysis (DTA), the material was sieved to retain included glass beads within the 90-125 micron size range. The DTAs were carried out on equipment obtained from Netzsch Instruments, Selb, Germany, under the trade name "NETZSCH STA 409 DTA / TGX". The amount of each sieved sample was 400 milligrams and was placed in an Al sample holder.₂OR₃ 100 microliters. Each sample was heated in a static atmosphere of air at a rate of 10 ° C / minute, from room temperature (approximately 25 ° C) to a temperature of 1200 ° C.

With respect to Fig. 1, line 345 corresponds to the graph of the DTA data of the material of Example 1. With respect to line 345 of Fig. 1, the material exhibited an endothermic event at a temperature of approximately 799 ° C , as evidenced by the downward curve of line 345. This event is believed to have been due to the glass transition (Tg) of the material. At approximately 875 ° C, an exothermic event was observed, evidenced by the sharp peak at line 345. This event is believed to have been due to crystallization (T_x) of the material. These Tg and Tx values ​​for other examples are collected in Table 3, previously presented.

Figures 2-6 correspond to the graphs of the DTA data for Examples 2, 5, 6, 7 and 9, respectively.

For Examples 1-9, approximately 25 grams of glass beads were placed in a graphite die and hot compressed using a uniaxial compression apparatus (obtained from Thermal Technology Inc., Brea, CA, with the trade name "HP-50"). Hot compression was carried out under argon atmosphere at 13.8 megapascals (MPa) (2000 pounds per square inch (2 ksi)) pressure. The hot compression temperatures at which an appreciable flow of glass occurred, indicated by the displacement of the control unit of the hot compression equipment described above, are collected, for examples 1-9, in Table 3, previously presented.