Heat treatable coated article with niobium nitride ir reflecting layer and method of making same

(21) Filing Number: 376559 (51) Int.Cl.

(22) Filing date: December 31, 2003 C03C 17/34 (2006.01)

Patent Office of the Republic of Poland (86) Date and number of the international application:

31.12.2003, PCT / US03 / 041831 (87) International application publication date and number:

2004-07-29, WO04 / 063111

The patent description has been reprinted due to the observed errors

<td colspan="2">(54) Heat-treated coated article</td>

<td>(30) Priority: 2003-01-09, US, 10 / 338,878</td><td>(73) The right holder of the patent: GUARDIAN INDUSTRIES CORP., Auburn Hills, US</td>

<td>(43) Application was announced: 09.01.2006 BUP 01/06</td><td>(72) Inventor (s): GRZEGORZ STACHOWIAK, Ann Arbor, US</td>

<td>(45) The grant of the patent was announced: August 31, 2010 WUP 08/10</td><td>(74) Representative: item. stalemate. Krystyna Krajewska</td>

PL 206 598 B1

Description of the invention

The present invention relates to a heat treated coated article that includes at least one infrared (IR) reflecting layer made of niobium nitride sandwiched between at least a pair of dielectric layers. Such a coated article may be used in the context of unit windows, insulated glass (IG) window units, laminated windows, and / or other suitable applications.

Background of the invention

Coatings controlling solar radiation having a layer system: glass / Si3N4 / NiCr / Si3N4 are known, in which the metallic NiCr layer is the only infrared (IR) reflecting layer in the coating. In some cases, the reflecting layer made of NiCr may be nitrided.

Unfortunately, while such sandwich systems provide effective solar radiation control and are generally good coatings, they are sometimes insufficient with respect to: (a) resistance to acid corrosion (eg, boiling HCl); (b) mechanical characteristics such as scratch resistance; and / or (c) after heat treatment for tempering, hot bending or the like (i.e., ∆ * values). For example, a known heat treatable coated article having a glass / Si3N4 / NiCr / Si3N4 layered system has an undesirably high glass side reflective ΔE * value of greater than 5.0 after heat treatment (HT) at 625 ° C for ten minutes. . This high glass side reflective value ΔE * means that the coated article, when heat treated, will not approximately match its untreated version for its glass side reflective color.

The prior art patent document US 2002/0192473 discloses a transparent substrate provided with a stack of thin layers affecting solar radiation, the stack comprising a functional layer formed of a metal (Nb, Ta, Zr) or metal nitride, and further comprising a layer of face made of aluminum nitride or oxynitride and / or silicon nitride or oxynitride. However, this document does not disclose an NbxNy system in which the ratio y / x of nitrogen to niobium would be 0.3 to 0.9.

Accordingly, there is a need for a coated article which has improved characteristics with respect to the above-mentioned features (a), (b) and / or (c) compared to a conventional glass / Si3N4 / NiCr / Si3N4 sandwich system, but which still allows for acceptable solar radiation control (e.g., significant IR and / or UV blocking) and / or heat treatment. It is an object of the present invention to meet at least one of the above-mentioned needs and / or other needs that will become apparent to those skilled in the art from reading the following disclosure.

The present invention provides a heat treated coated article comprising a layer system deposited on a glass substrate, including:

a first layer comprising silicon nitride;

a niobium nitride-containing layer disposed on the glass substrate over the first silicon nitride-containing layer characterized in that the niobium nitride-containing layer is shown as NbxNy, wherein the ratio y / x N to Nb is 0.3 to 0.9;

and the article further comprises a second layer comprising silicon nitride disposed on the glass substrate over the layer comprising niobium nitride;

wherein a layer including niobium nitride is sandwiched between and in contact with each of the first and second layers including silicon nitride; and wherein the coated article has a ∆E * (glass side reflective) value of no greater than 3.0 after and / or due to heat treatment.

Preferably, the coated article of the invention has a visible transmission of from 8 to 80%, and at least one of the silicon nitride-containing layers further comprises at least one of stainless steel, aluminum and oxygen, and wherein the coated article of the invention has a ΔE * value. (reflective on the glass side) no more than 2.5 after and / or due to heat treatment.

Preferably, the coated article of the invention has a ΔE * (glass side reflective) of no greater than 2.0 after and / or due to heat treatment, and wherein the heat treatment is for at least 5 minutes at a temperature (s) of at least 580 ° C. , or more preferably the article has a ∆E * (glass side reflective) value of no greater than 1.8 after and / or due to heat treatment,

And the ratio y / x is from 0.4 to 0.8, even more preferably the ratio y / x is from 0.5 to 0.7, most preferably the ratio y / x is from 0.55 to 0, 65.

According to a preferred embodiment of the coated article of the invention, the layered system comprises first and second layers containing silicon nitride and a layer containing niobium nitride, and preferably the article has layers other than the metallic infrared reflecting layer, the layer containing niobium nitride being in contact with the other layer. than the metal layer, and the layer containing niobium nitride is made to be nitrided during the deposition. Preferably, the coated article of the invention is an IG window unit, a solid window, or a laminated window, and has been heat treated for at least 5 minutes at a temperature of at least 580 ° C.

In certain example embodiments of this invention, there is provided a coating or layering that includes an infrared (IR) reflecting layer including niobium nitride sandwiched between at least a pair of dielectric layers. In certain example embodiments, the coating or layering has good corrosion resistance to acid (s) such as HCl, good mechanical performance such as scratch resistance, and / or good color fastness (i.e., low ΔΕ value (s)). * after heat treatment (HT).

Due to the spectral selectivity, niobium nitride provides thermal characteristics (e.g., IR blocking) similar to NiCr but surprisingly more chemically and / or mechanically stable than NiCr. The use of niobium nitride as an infrared reflecting layer results in a solar control coating that has excellent scratch resistance, and its resistance to acids such as HCl is exceptional. Its resistance to alkaline solutions is also good. Moreover, it has surprisingly been found that the use of niobium nitride as an infrared reflecting layer enables the solar control coating to have significantly better thermal stability after heat treatment (e.g., a lower ΔE * value for a given heat treatment time) than the above-mentioned conventional coating in which as the infrared radiation reflecting layer uses metallic NiCr.

A coated article according to an example embodiment of this invention utilizes such a niobium nitride layer sandwiched between a pair of dielectric layers made of silicon nitride.

Coated articles according to certain embodiments of this invention may be used as unitary windows due to their excellent durability characteristics which may or may not be heat treated. Alternatively, coated articles of the present invention may also be used in the context of an IG window unit or in other suitable applications which may or may not involve heat treatment.

In certain example embodiments of this invention, heat treated (HT) coated articles including an infrared reflecting layer made of niobium nitride have a glass side reflective value ΔE * of no greater than 3.0, more preferably no greater than 2.5. , even more preferably no greater than 2.0, and most preferably no greater than 1.8. For example, the heat treatment (HT) may be for at least about 5 minutes at the temperature (s) of at least about 580 ° C.

Generally speaking, certain example embodiments of this invention meet one or more of the above-mentioned needs by providing a heat treated coated article including a sandwich system deposited on a glass substrate, the sandwich system comprising: a first layer including silicon nitride; a layer containing niobium nitride provided on the glass substrate over the first layer containing silicon nitride; a second layer containing silicon nitride located on the glass substrate over the layer containing niobium nitride; wherein a layer including niobium nitride is sandwiched between, and contacting each of the first and second layers including silicon nitride; and wherein the coated article has a ∆E * (glass side reflective) value of no greater than 3.0 after and / or due to heat treatment.

In certain other example embodiments of this invention, one or more of the above needs are / are met by providing a heat treatable coated article including a coating deposited on a glass substrate, the coating comprising: a first dielectric layer; a layer containing niobium nitride; a second dielectric layer; and wherein the layers of the coated article are made of and have suitable substances

Suitable thicknesses such that when it is heat treated for at least about 5 minutes at the temperature (s) of at least about 580 ° C, the coated article will have a value of

ΔΕ * (reflective from the glass side) not more than 3.0.

In certain other example embodiments of this invention, one or more of the needs listed above are / are met by providing a coated article including a layer system deposited on a glass substrate, the layer system comprising: a first dielectric layer; a layer containing niobium nitride NbxNy located on the glass substrate over the first dielectric layer, wherein the ratio y / x N to Nb in the layer containing niobium nitride is from 0.3 to 0.9; and a second dielectric layer disposed on the glass substrate over the layer containing niobium nitride.

Fig. 1 is a partial cross sectional view of an embodiment of a unitary coated article (heat treated or not heat treated) according to an example embodiment of this invention.

Fig. 2 is a partial cross sectional view of an IG window unit, such as that contemplated in the present invention, in which the coating or layer system of Fig. 1 may be used.

Fig. 3 is a graph that plots the nitrogen gas flow (during cathode sputtering of a niobium nitride layer) against the Nb, N atomic content of the resulting layer, illustrating the stoichiometry of the niobium nitride layers according to various embodiments of this invention as a function of nitrogen gas flow during sputtering ( N and Nb atomic percentages were determined using XPS (X-ray photoelectron spectroscopy).

Fig. 4 is a graph that plots the nitrogen gas flow as a percentage of the total gas flow during sputtering a niobium nitride layer versus the resulting y / x ratio (for a given NbxNy) in the resulting niobium nitride layer according to various embodiments of this invention, thus illustrating various layer stoichiometries as a function of the amount of nitrogen in the total gas flow during sputtering (atomic percentages of N and Nb were determined using XPS).

Fig. 5 is a graph that plots the nitrogen gas flow (in sccm - standard cubic centimeters) during the cathode sputtering of the niobium nitride layer versus the resulting y / x ratio (for a given NbxNy) in the resulting niobium nitride layer according to various embodiments of this invention, illustrating this method, various stoichiometries of the layer as a function of nitrogen gas flow during sputtering (atomic percentages of N and Nb were determined using XPS).

Detailed description of certain example embodiments of this invention.

Certain embodiments of the present invention provide a coating or sandwich system that can be used in windows such as solid windows (e.g., vehicle windows, residential windows, or building windows), IG window units, and / or other suitable applications. Certain example embodiments of this invention provide a sandwich system that has good (a) resistance to acid corrosion (e.g., which can be tested by boiling in HCl); (b) mechanical performance, such as scratch resistance; and / or (c) thermal stability after heat treatment. Regarding the thermal stability after heat treatment (HT), this means a low ΔE * value where Δ is the change index from the HT point of view, such as quenching, hot bending, or thermal heating for strengthening, monolithic and / or in the context of double-pane environments, such as IG units or laminates. Such heat treatments sometimes require heating the coated substrate to temperatures from about 580 ° C to about 800 ° C for 5 minutes or more.

Fig. 1 is a side cross sectional view of a coated article according to an example embodiment of this invention. The coated article includes at least substrate 1 (e.g. a glass substrate of clear, green, brown, gray, blue, or blue-green glass with a thickness of about 1.0 to 12.0 mm), a first dielectric layer 2 (e.g., made of or including silicon nitride (e.g., Si3N4), tin oxide, or some other dielectric substances), infrared reflecting layer 3 made of or including niobium nitride (Nb_xN_y), and a second dielectric layer 4 (e.g., made of or including silicon nitride (e.g., Si₃N₄), tin oxide, or other suitable dielectric substance). In certain example embodiments of this invention, coating 5 does not include any IR reflecting metallic layer such as Ag or Au. In such embodiments, the niobium nitride-containing infrared reflecting layer 3 may be the only infrared reflecting layer in the coating 5. In certain example embodiments of this invention, the niobium nitride infrared reflecting layer 3 does not contact any metallic infrared reflecting layer.

The total coating 5 comprises at least layers 2-4. It is noted that the terms "oxide and" nitride in the context of the present invention encompass a variety of stoichiometry. For example, the term silicon nitride includes stoichiometric Si3N4 as well as non-stoichiometric silicon nitride such as Si enriched silicon nitride. Layers 2-4 may be deposited on substrate 1 by magnetron sputtering or any other suitable technique in various embodiments of this invention.

In certain example embodiments of this invention, infrared reflecting layer 3 is sputter-deposited in the form of niobium nitride. The stoichiometry of this layer after deposition may be depicted, in certain example embodiments, as NbxNy, where the ratio y / x (i.e., the ratio of N to Nb) is from 0.3 to 0.9, more preferably from 0.4 to 0. 8, even more preferably from 0.5 to 0.7, and most preferably from 0.55 to 0.65. By way of example only, niobium nitride in the form of Nb5N3 translates to a y / x ratio of 3/5 (i.e., 0.6). It has surprisingly been found that the above-mentioned y / x ratios for niobium nitrides are particularly advantageous with regard to coating characteristics such as spectral curves and / or chemical resistance. For example, nitriding with Nb in amounts greater than this may result in a lower chemical resistance of the coating 5. In other words, if the ratio y / x is greater than the above-mentioned range (s), the chemical stability is lowered. Also, if the y / x ratio is less than the above-mentioned range (s), the solar control characteristic experiences effects such that not exactly the same amount of infrared radiation is blocked (reflected and / or absorbed) by the coating.

While Fig. 1 illustrates the coating 5 in the way that layer Nb_xN_y 3 is in direct contact with the dielectric layers 2 and 4, and in which the Nb layer_xN_y 3 is the only IR reflecting layer in the coating, the present invention is not so limited. In certain other embodiments of this invention, other layer (s) may be provided between layers 2 and 3 (and / or between layers 3 and 4). Further, other layer (s) may be provided between substrate 1 and layer 2 in certain example embodiments of this invention; and / or other layer (s) on substrate 1 may be provided over layer 4 in certain embodiments of this invention. Thus, while the coating 5 or layers thereof are / are "on or are" deposited on the substrate 1 (directly or indirectly), other layer (s) may be interposed therebetween. Thus, for example, the layer system 5 and its layers shown in Fig. 1 are considered to be "on the substrate 1 even though other layer (s) may be interposed therebetween (i.e., the terms" on and "embedded" as used in this patent application are not limited to direct contact).

Surprisingly, it was found that the use of Nb_xN_y in layer 3 (as opposed to NiCr itself) results in a coated article having: (a) improved resistance to acid corrosion such as HCl; (b) improved mechanical durability, such as better scratch resistance; and / or (c) improved thermal stability (ie, lower ΔE value (s)) in the context of the heat treatment coating.

In certain example embodiments of this invention, each of the antireflection dielectric layers 2 and / or 4 may have a refractive index "n" of from about 1.5 to 2.5, more preferably from 1.9 to 2.3. While layer 3 may have an "n ratio" of from about 2.0 to 2.4, more preferably from about 2.17 to 2.3 in certain example embodiments of this invention. The antireflection function of the dielectric (s) is related to the complex refractive index (n + k). In certain example embodiments of this invention, a difference in the complex factor (k for the silicon nitride is about 0.01 or less, while the k for the niobium nitride layer is about 2.5 to 3.1 at 550 nm) allows the desired anti-reflection effect to be achieved. . The increased transmittance is a result of partly reduced reflection and partly reduced absorption. In embodiments of the present invention wherein layers 2 and / or 4 comprise silicon nitride (e.g., Si₃N₄), the Si-containing sputtering targets used to form these layers may or may not be doped with 6-20% by weight of aluminum and / or stainless steel (e.g. SS 316), with nearly the same amount subsequently appearing in layers produced in this way.

PL 206 598 B1

While Fig. 1 illustrates a coated article according to an embodiment of this invention in unitary form. Fig. 2 illustrates the coating or layer system 5 of Fig. 1 applied to surface 2 of an IG (insulating glass) window unit. In Fig. 2, two glass substrates (e.g., 2mm to 12mm thick float glass) 1, 7 are sealed at the peripheral edges with conventional sealant and / or spacer (not shown) and can be supplied with a conventional desiccant tape ( not shown). The panes are then held in a conventional window or door mounting frame. By sealing the peripheral edges of the glass sheets and replacing the air in the insulation space (or chamber) 9 with a gas such as argon, a highly insulating value of the IG unit is produced as illustrated in Fig. 2. Alternatively, the insulation space 9 can be kept under pressure less than the pressure. atmospheric in certain other embodiments, however, of course not necessarily in all IG embodiments. In IG embodiments, the coating 5 of Fig. 1 may be provided on the inner wall of substrate 1 in certain embodiments of this invention (as in Fig. 2), and / or on the inner wall of substrate 7 in other embodiments of this invention.

Returning to Fig. 1, where different thicknesses may be used in accordance with one or more of the items and / or needs considered above. According to certain non-limiting example embodiments of this invention, exemplary thicknesses and materials for respective layers on the glass substrate 1 are as follows:

Table 1 (examples of non-limiting thicknesses)

<td>Layer</td><td>Sample range nm (A)</td><td>favorable nm (A)</td><td>best nm (A)</td>

<td>Silicon nitride (layer 2):</td><td>1-100 nm (10-1000 A)</td><td>2-90 nm (20-900 A)</td><td>3-85 nm (30-850 A)</td>

<td>NbxNy (layer 3):</td><td>5-70 nm (50-700 A)</td><td>1-50 nm (100-500 A)</td><td>15-35 nm (150-350 A)</td>

<td>Silicon nitride (layer 4)</td><td>1-90 nm (100-900 A)</td><td>15-80 nm (150-800 A)</td><td>20-50 nm (200-500 A)</td>

In certain example embodiments, the color fastness due to the long heat treatment can result in significant matchability between the heat treated and untreated versions of the coating or layer system. In other words, in unitary and / or IG applications, in certain embodiments of this invention, two glass substrates having the same coating system applied (one HT post deposited and the other not HT treated) appear substantially the same by the naked human eye. To put it another way, the coated article has good color stability after heat treatment.

The ∆E * value (s) is important in determining whether or not there is a post-HT color matchability or significant color matchability in the context of certain embodiments of the present invention (i.e., the determination of ∆E * is important in determining color fastness after color treatment) heat). The color in this patent application has been described with reference to typical a *, b * values. For example, the term ∆a * is indicative of how much the color value of a * changes due to heat treatment.

The term ΔE * (and ΔE) is well understood and described, along with various techniques for its determination, in ASTM 2244-93 as well as described by Hunter et al., The Measurement of Appearance, Second Edition, ch. 9, page 162 et seq. (John Wiley &amp; Sons, 1987). As used, ∆E * (and ∆E) is a way of adequately expressing the change (or lack thereof) in reflectance and / or transmittance (and thus also color appearance) of an article after or due to HT. ΔE can be calculated using the "ab" technique or the Hunter technique (denoted by the use of "H in subscript). ΔE corresponds to the L, a, b scale; Hunter Lab (or L._h, a_h, b_h). Similarly, ΔE * corresponds to the L *, a *, b * CIE LAB scale. Both are considered to be useful and equivalent for the purposes of the present invention. For example, as described above by Hunter et al., A rectangular coordinate / scale technique (CIE LAB 1976) known as the L *, a *, b * scale can be used, where:

L * means (CIE 1976) luminous units a * means (CIE 1976) red-green units b * means (CIE 1976) yellow-blue units and the distance ΔE * between L *_about and*_about b *_about and L *₁ and*₁ b *_andis:

ΔΕ * = {(AL *)² + (Aa *)² + (Ab *)²} * (1) where:

ΔL * = L * 1 - L * o (2)

PL 206 598 B1

Δα * = a *₁- a *_about (3)

Ab * = b *₁ - b *_about (4) where "subscript" is the coating (or coated article) before heat treatment and "1" subscript is the coating (coated article) after heat treatment; and the numbers used (e.g., a *, b *, L *) are those calculated by the L *, a *, b * coordinate technique mentioned above (CIE LAB

1976). Similarly, AE can be calculated using equation (1) by replacing a *, b *, L * with the values ​​of Hunter Lab a_h, b_h, L._h. Also within the scope of the present invention and the estimation of AE * they are equivalent numbers if converted to those calculated by any other technique using the same concept of AE * as defined above.

After heat treatment (HT) such as tempering, in certain example embodiments of this invention, coated articles have color characteristics as follows in Table 2. "G in the subscript corresponds to the glass side reflective color," T in the glass side. subscript corresponds to transmissive color, and "F subscript corresponds to the color facing the film." As is known, the glass side (G) is reflective color when viewed from the glass side (as opposed to the layer / film side) of the coated article. Film side (F) (not shown in Table 2) represents a reflective color when viewed from the side of the coated article on which the coating 5 is provided.

Table 2: Color / Optical characteristics due to / after heat treatment

<td></td><td>general</td><td>beneficial</td><td>the most advantageous</td>

<td>AE * g</td><td> &lt; = 3,0</td><td> &lt; = 2,5</td><td> &lt; = 2,0</td>

<td>AE * Vol</td><td> &lt; = 5,0</td><td> &lt; = 2,5</td><td> &lt; = 2,0</td>

<td>a * G</td><td>-6 to +6</td><td>-4 to +4</td><td>-3 to +3</td>

<td>b * G</td><td>-30 to +25</td><td>-25 to +20</td><td>-20 to +10</td>

<td>Aa * G</td><td> &lt; = 1,6</td><td> &lt; = 1,0</td><td> &lt; = 0,8</td>

<td>Ab * G</td><td> &lt; = 1,5</td><td> &lt;=1,0</td><td> &lt; = 0,6</td>

<td>AL * g</td><td> &lt; = 5</td><td> &lt; = 3</td><td> &lt; = 2</td>

<td>Tvis (YOU)</td><td> 8 - 80%</td><td> 10 - 50%</td><td> 10 - 30%</td>

<td>Rs (Ω / Π):</td><td> &lt; 250</td><td> &lt; 150</td><td> &lt; 110</td>

Coated articles according to this invention may even have an AE * (AE * G) glass side reflective value of no greater than 1.8 in certain example embodiments of this invention.

3-5 illustrate different stoichiometry of the niobium nitride layer 3 according to various embodiments of the present invention. In particular, these figures illustrate different N to Nb ratios in niobium nitride layer 3 as a function of nitrogen gas flow during a sputtering process in which layer 3 is sputter-deposited. In these figures, the atomic percentages of N and Nb (at.%) Were determined using XPS. Additionally, it is noted that the correlation between the nitrogen gas flows and the N to Nb ratio (s) was determined according to the ILS coater used to deposit these samples as the flows were measured in this sputter coater. Fig. 3 is a graph that plots the nitrogen gas flow (during sputtering of a niobium nitride layer) versus the Nb, N atomic content of the resulting layer, illustrating the stoichiometry of the niobium nitride layers according to various embodiments of this invention as a function of nitrogen gas flow during sputtering. Fig. 4 is a graph that plots the nitrogen gas flow as a percentage of the total gas flow during sputtering of the niobium nitride layer versus the resulting y / x ratio (for a given NbxNy) in the resulting niobium nitride layer according to various embodiments of this invention, thus illustrating the various stoichiometry of the layer as a function of the amount of nitrogen in the total gas flow during sputtering. Fig. 5 shows a graph that plots the nitrogen gas flow [in units of cm³(sccm)] when cathodically sputtering the niobium nitride layer relative to the obtained y / x ratio (for a given NbxNy) in the obtained niobium nitride layer according to various embodiments ni8

According to the present invention, thus illustrating the various stoichiometry of the layer as a function of nitrogen gas flow during sputtering. As explained above, the best performance (balancing durability and solar radiation control characteristics) occurs when the Nb layer_xN_y 3 is defined by the ratio y / x N to Nb being from 0.3 to 0.9, more preferably from 0.4 to 0.8, more preferably from 0.5 to 0.7, and most preferably from 0.55 to 0. 65.

By way of example only, a number of examples are provided below, representing various exemplary embodiments of the present invention.

Examples

The following two exemplary unitary coated articles (each finally annealed and heat treated) were produced. Si layers₃N₄ 2 and 4 in each example were deposited by sputtering a silicon target (doped with Al) in an atmosphere including nitrogen gas. The niobium nitride layer 3 in each example was deposited by sputtering in an atmosphere including argon and nitrogen gas.

In Example 1, the following sputtering process parameters were used to deposit the coating. The linear speed is given in meters per second (inches per minute):

TABLE 3: Example 1 - Coating process parameters

<td>layer</td><td>power</td><td>tension</td><td>Linear speed</td><td># go</td><td>Ar flow</td><td>Flow N</td>

<td>SiN layer 2:</td><td>2.5 kW</td><td>486 V</td><td> 2,1*10^-2 (49,5)</td><td> 8</td><td> 40</td><td> 55</td>

<td>NbxNy layer 3:</td><td>1.0 kW</td><td>426 V</td><td> 1,4*10^-2 (33)</td><td> 3</td><td> 30</td><td> 12</td>

<td>SiN layer 4:</td><td>2.5 kW</td><td>482 V</td><td> 2,1*10^-2 (49,5)</td><td> 3</td><td> 40</td><td> 55</td>

In Example 2, the following sputtering process parameters were used to deposit the coating. Again, the linear speed is given in meters per second (inches per minute):

TABLE 4: Example 2 - Coating process parameters

<td>layer</td><td>power</td><td>tension</td><td>Linear speed</td><td>go through</td><td>Ar flow</td><td>Flow N</td>

<td>SiN layer 2:</td><td>1.0 kW</td><td>453 V</td><td> 1,74*10' (41,2)</td><td> 1</td><td> 40</td><td> 55</td>

<td>NbxNy layer 3:</td><td>1.0 kW</td><td>432 V</td><td> 1,54*10' (36,3)</td><td> 3</td><td> 30</td><td> 12</td>

<td>SiN layer 4:</td><td>1.0 kW</td><td>448 V.</td><td> 1,74*10' (41,2)</td><td> 6</td><td> 40</td><td> 55</td>

After sputtering, Examples 1-2 had the following sputter characteristics (annealed and untreated) (Ill. C, 2 step observation):

Table 5: Characteristics (not heat treated)

<td>parameter</td><td>Example 1</td><td>Example 2</td>

<td> 1</td><td> 2</td><td> 3</td>

<td>Tvis (TY) (permeable):</td><td> 19,6%</td><td> 19,7%</td>

<td>a * T</td><td> -2,4</td><td> -1,4</td>

<td>b * T</td><td> -3,4</td><td> -8,3</td>

<td>L * t</td><td> 51,4</td><td> 51,5</td>

<td>R_gY (glass side reception%):</td><td> 20,3%</td><td> 31,8%</td>

<td>a * G:</td><td> 0,8</td><td> -1,3</td>

<td>b * G:</td><td> -14,5</td><td> -0,9</td>

PL 206 598 B1 cont. table 5

<td> 1</td><td> 2</td><td> 3</td>

<td>1 * LG:</td><td> 52,2</td><td> 63,2</td>

<td>RfY (glass side reception%):</td><td> 28,9%</td><td> 23%</td>

<td>a * F:</td><td> 1,4</td><td> 1,8</td>

<td>b * F</td><td> 34,4</td><td> 25,6</td>

<td>L * f:</td><td> 60,7</td><td> 55,1</td>

<td>Tsol (TS):</td><td> 14%</td><td> 14%</td>

<td>shading coefficient (SC):</td><td> 0,37</td><td> 0,34</td>

<td>SHGC (Solar Energy Coefficient):</td><td> 0,32</td><td> 0,30</td>

<td>Tuv (UV transmission):</td><td> 15%</td><td> 19,2%</td>

<td>(Rs) (specific resistance; ohms / d):</td><td> 97,7</td><td> 103</td>

Examples 1 and 2 each had the following layering as shown in Table 6. The thicknesses and stoichiometries listed below in Table 6 for the Examples are approximate and not exact.

Coating 5 for each example is shown in Fig. 1 and thus comprised layers 2, 3 and 4. The glass substrates were transparent and about 6 mm thick in each example.

TABLE 6: Coating in the examples

<td>Example 1:</td><td>glass / SiaN4 [80 nm (800 A)] / NbxNy [25.4 nm (254 A)] / Si3N₄[30 nm (300 A)]</td>

<td>Example 2:</td><td>glass / SiaN₄ [5 nm (50 A)] / NbxNy [23.1 nm (231 A)] / SiaN₄ [30 nm (300 A]</td>

After sputter coating, Examples 1 and 2 were each then heat treated for 10 minutes at about 625 ° C. Table 7 below summarizes some of the characteristics of the thermal stability of Examples 1-2 during / after heat treatment (HT).

Table 7: Thermal stability of the reflective values ​​on the glass side after heat treatment

<td>parameter</td><td>Example 1</td><td>Example 2</td>

<td>ΔE * G:</td><td> 1,7</td><td> 1,4</td>

As can be seen from Table 7, each of the examples had excellent glass side reflective ΔE * values. The low numbers associated with these values ​​illustrate how little the optical characteristics of the coating changed after heat treatment. This is an indicator of better thermal stability after heat treatment (e.g., quenching, or the like).

For comparison, the following layer system was considered: glass / Si3N4 / NiCr / Si3N4 which has a glass side reflective value ΔE * greater than 5.0 after heat treatment (HT) at 625 ° C for ten minutes. The above Examples 1-2 clearly illustrate the relative advantage of using niobium nitride as opposed to NiCr in the IR reflecting layer. By using niobium nitride, a much lower ΔE * reflective value on the glass side can be obtained. Moreover, the durability can also be improved as explained above.

Accordingly, the benefits of using niobium nitride as an infrared reflecting layer include (a) improved corrosion resistance with respect to an acid such as HCl; (b) improved mechanical characteristics, such as better scratch resistance; and / or (c) improved thermal stability (i.e., lower ΔE * value (s)). In certain embodiments of this invention, coated articles may or may not be heat treated.

Certain terms are commonly used in the glass coating field, particularly in determining solar control properties and characteristics for coated glass. Such terms are used in this patent application according to their well-known meaning. For example, as used in this patent application:

PL 206 598 B1

The intensity of the reflected light in the visible wavelength, that is, "the reflectance is determined by its percentage ratio and is reported as RxY (that is, the Y value, quoted below in ASTM E-308-85), where" X is both " G for the glass side and F for the film side. "Glass side (eg. "G) means looking from the side of the glass substrate opposite to that facing the coating, while the" side of the film (ie, "F) means looking from the side of the glass substrate where the coating is located.

Color characteristics were measured and reported in this patent application using CIE LAB a *, b * coordinates and scale (i.e., CIE a * b * plot, I11. CIE-C, 2 step observation). Other similar coordinates may be used equivalently, such as "h in subscript" is used to denote a conventional use of the Hunter Lab scale, or I11. CIE-C, 10 ° observation, or CIE LUV u * v * coordinates. These scales are defined in this patent application according to ASTM D-2244-93 "Standard Test Method for Calculation of Color Differences from Instrumentally Measured Color Coordinates 9/15/93 as extended in ASTM E-308-85, ASTM Standards Yearbook, Vol. 06.01. Standard Method for Computing the Colors of Objects by 10 Using the CIE System and / or as set forth in lES LIGHTING HANDBOOK 1981 Reference Volume.

The terms "emittance and" transmittance are well understood and are used in this patent application according to their well-known meanings. Thus, for example, the terms visible light transmittance (TY), infrared transmittance, and ultraviolet transmittance (Tuv) are known. Total solar energy transmittance (TS) is therefore usually characterized as a weighted average of these values ​​from 300 to 2500 nm (UV, visible range and near infrared). With regard to these transmittances, visible transmittance (TY) as described in this patent application is determined by the standard CIE Illuminant C, 2-stage observation technique at 380-720 nm; near infrared is 720 - 2500 nm; ultraviolet is 300-800 nm; and the total solar radiation is 300-2500 nm. For the purposes of emittance, however, a specific infrared range (i.e., 2500 - 40,000 nm) is used.

Visible transmittance can be measured using known, conventional techniques. For example, using a spectrophotometer such as a Perkin Elmer Lambda 900 or Hitachi U4001, a spectral transmission curve is obtained. The visible transmission is then calculated using the ASTM 308 / 12244-93 methodology mentioned above. Less than the recommended number of points for each length may be used, if desired. Another technique for measuring visible transmittance is to use a spectrometer, such as the commercial Spectrogard spectrophotometer manufactured by Pacific Scientific Corporation. This device measures and reports visible transmittance directly. As described and measured in this patent application, I11 is used for visible transmittance (ie, Y values ​​in a CIE tristimulus system, ASTM E-308-85). C., 2-step observation.

Another term used in this patent application is "specific resistance. Specific resistance (Rs) is a well-known term and has been used in this patent application in accordance with its well-known meaning. It is expressed in this patent application in ohms per unit area. Generally speaking, the term refers to the resistance in ohms per any square of a layer system on a glass substrate to the electric current flowing through the layer system. Specific resistance is an indicator of how well the layer or layer system is reflecting infrared energy, and is therefore often used along with emittance as a measure of this feature. "Specific resistance can, for example, be conveniently measured with a 4 point ohmmeter tester, such as a disposable 4 point resistivity tester from Magnetron Instruments Corp, head. The M-800 model produced by Signatone Corp. from Santa Clara, California.

"Chemical stability or" chemically stable is used in this patent application synonymously with the terms "chemically resistant or" chemically stable. For example, chemical stability can be determined by boiling a sample of the coated glass substrate in about 500 cubic centimeters of 5% HCl for one hour (i.e., about 91 ° C (195 ° F). Alternatively, chemical stability can be determined by cooking in NaOH, which includes boiling a sample of the coated glass substrate in a solution having a pH of about 12.2, that is, a mixture of water and NaOH (about 0.4% NaOH); the solution can be obtained from LabChem, Inc., Cat. Well. LC 24270-4 (this is what is meant by cooking in NaOH according to the present patent application). Cooking in NaOH can

Performed at about 63 ° C (145 ° F) (Examples above), or about 90 ° C (195 ° F) in other instances.

The terms "heat treatment and" heat treatment in the sense of the present invention mean heating an article to a temperature sufficient to allow the glass-containing article to be tempered, bent, or hot straightened. This definition includes, for example, heating a coated article to a temperature of at least about 580 ° C for a time sufficient to permit improvement. In some cases, the heat treatment may be for at least about 4 or 5 minutes.

Many other features, changes, and improvements will become apparent to those skilled in the art upon giving the above disclosure. Such other features, changes and improvements are therefore considered part of the present invention, the scope of which is defined in the following claims.