Heat treatable coated article with diamond-like carbon (dlc) coating

ES 2 328 040 T3

DESCRIPTION

Heat treatable coated article with diamond type carbon coating (DLC).

The present invention relates to a process for manufacturing a coated article for use in a window unit or any other suitable application. For example, certain embodiments of the present invention relate to a method of manufacturing a window unit (for example, a vehicle window such as a vehicle windshield, rear window, sunroof or side windows, or a window unit IG) that includes a step of heat treatment of a glass substrate coated with at least one layer comprising diamond-like carbon (DLC). Other embodiments of the present invention relate to such a coated article that can be used in window applications or any other appropriate application.

Background of the invention

Vehicle windows (eg, windshields, rear windows, sunroofs, and side windows) are known in the art. For example purposes, vehicle windshields typically include a pair of curved glass substrates laminated together by a polymeric interlayer such as polyvinyl butyral (PVB). It is known that one of the two glass substrates can have a coating (e.g. low-emissivity coating) on ​​it for solar control purposes such as reflection of IR and / or UV radiation, so that the interior of the vehicle can be more comfortable in some weather conditions. Conventional vehicle windshields are manufactured as follows. A first and a second flat glass substrate are provided, one of which optionally has a low-emissivity coating sprayed thereon. The pair of glass substrates are washed and put together (e.g. stacked on top of each other), and then while together they are hot bent together to the desired windshield shape at high temperature (s) ( eg 8 minutes at about 600-625 degrees C). The two curved glass substrates are then laminated together by the polymeric interlayer to form the vehicle windshield.

Insulating glass (IG) window units are also known in the art. The conventional IG window unit includes at least a first and a second glass substrate (one of which may have a solar control coating on an interior surface thereof) that are coupled to another by at least one gasket (s). (s) or spacer (s). The resulting space or gap between the glass substrates may or may not be filled with gas and / or emptied at low pressure in different cases. However, many IG units are required to be tempered. Heat tempering of glass substrates for such IG units typically requires heating the glass substrates to temperature (s) of at least about 600 degrees C for a period of time sufficient to allow heat tempering.

Other types of coated articles also require heat treatment (HT) (eg tempering, heat bending and / or heat reinforcement) in certain applications. For example and without limitation, glass shower doors, glass table tops, and the like require HT in some cases.

Diamond-like carbon (DLC) is sometimes known for its scratch-resistant properties. For example, different types of DLC are mentioned in the following US patents: 6,303,226; 6,303,225; 6,261,693; 6,338,901; 6,312,808; 6,280,834; 6,284,377; 6,335,086; 5,858,477; 5,635,245; 5,888,593; 5,135,808; 5,900,342; and 5,470,661, all of which are incorporated herein by reference.

Sometimes it would be desirable to provide a window unit or other glass article with a protective coating that includes DLC to protect it from scratches and the like. Unfortunately, DLC tends to oxidize and burn at temperatures of about 380 to 400 degrees C, since the heat treatment is typically carried out in an atmosphere that includes oxygen. Thus, it will be appreciated that DLC as a protective coating cannot withstand heat treatments (HT) at the extremely high temperatures described above, which are often required in the manufacture of vehicle windows, IG window units, dashboards. glass table and / or the like.

Accordingly, those skilled in the art will appreciate that there is a need in the art for a method of providing heat treatment (HT) coated articles with a protective coating (one or more layers) comprising DLC. There is also a need for corresponding coated articles, both by heat treatment and by pre-HT.

Brief summary of invention examples

In certain exemplary embodiments of the present invention, there is provided a process for manufacturing a coated article (eg, window unit such as for a vehicle, building, or the like), including heat treatment (HT), in the which the coated article includes a coating (one or more layers) comprising diamond-like carbon (DLC).

In certain exemplary embodiments, a method of manufacturing a coated article is provided: (a) providing at least one barrier layer supported by a glass substrate, (b) coating a glass substrate with a layer comprising DLC on at least the barrier layer, then (c) form a protective layer

ES 2 328 040 T3 on the glass substrate on the DLC and (d) heat treating the DLC coated article and the sacrificial protective layer therein with the protective layer preventing most of the DLC from burning during heat treatment . Following heat treatment (HT), the sacrificial protective layer can be removed. The resulting heat-treated coated article can be used in the context of, for example and without limitation, vehicle windows, architectural windows, insulating glass (IG) window units, shower doors, glass table tops, and / or the like. .

In certain exemplary embodiments of the present invention, the sacrificial protective layer may comprise zirconium nitride.

In other exemplary embodiments of the present invention, the sacrificial protective layer may comprise chromium nitride.

In certain exemplary embodiments of the present invention, a method of manufacturing a heat-treated coated article is provided, the method comprising: providing a glass substrate; forming at least one layer comprising diamond-like carbon (DLC) on the glass substrate; forming a protective layer comprising a zirconium and / or chromium nitride on the glass substrate over at least the layer comprising DLC; heat treating the glass substrate with the layer comprising DLC ​​and the protective layer comprising the zirconium and / or chromium nitride therein so that, during the heat treatment, the protective layer prevents significant burning of the layer comprising DLC, and remove at least part of the protective layer comprising the zirconium and / or chromium nitride after said heat treatment.

In other exemplary embodiments of the present invention, a coated article is provided that includes a coating supported by a glass substrate, the coating comprising: at least one barrier layer supported by the glass substrate; a layer comprising diamond-like carbon (DLC) on the glass substrate over at least the barrier layer; and a layer comprising a zirconium and / or chromium nitride on the glass substrate over at least the layer comprising DLC.

Brief description of the drawings

Figure 1 is a cross-sectional view of a coated article, prior to heat treatment, in accordance with an exemplary embodiment of the present invention.

Figures 2 (a) -2 (c) are cross-sectional views illustrating certain steps carried out in the manufacture of a coated article in accordance with an exemplary embodiment of the present invention.

Figure 3 is a cross-sectional view of a coated article made by the process of Fig. 2 in accordance with an exemplary embodiment of the present invention.

FIG. 4 is a cross-sectional view of an IG window unit including the coated article of FIG. 3 in accordance with an exemplary embodiment of the present invention.

Detailed description of examples of the invention

Referring now more particularly to the accompanying drawings, reference numerals indicate similar parts throughout the various views.

Certain exemplary embodiments of the present invention relate to coated article manufacturing processes that may use heat treatment (HT), in which the coated article includes a coating (one or more layers) that includes diamond-like carbon. (DLC). In certain cases, the heat treatment may comprise heating a support glass substrate, with the DLC in it, to temperature (s) of 550 to 800 degrees C, more preferably 580 to 800 degrees C (which is well below above the DLC burn temperature). In particular certain exemplary embodiments of the present invention relate to a technique for allowing the DLC to withstand such heat treatment without significantly burning during the treatment. In certain embodiments, a sacrificial protective layer is formed on the glass substrate over the DLC to thereby reduce the likelihood of burning of the DLC during HT. In this way, most (or all) of the DLC remains on the glass substrate, and does not burn, during HT. After HT, the sacrificial protective layer may or may not be removed in different embodiments of the present invention.

FIG. 1 is a cross-sectional view of a coated article in accordance with an exemplary embodiment of the present invention. Typically, the coated article of Fig. 1 exists during a manufacturing step prior to heat treatment, but may also exist post-HT in certain cases. The coated article shown in Fig. 1 includes glass substrate 1, at least one barrier layer 6, DLC inclusive layer 11, and sacrificial protective layer 17. Glass substrate 1 is typically of, or includes, sodium-calcium silica glass, although other types may be used. glass in certain cases.

Barrier layer 6 is provided to reduce or prevent migration of oxygen and / or sodium (Na) from glass 1 to DLC 11 during HT. To this end, the barrier layer 6 improves the overall optical characteristics of the coated article.

ES 2 328 040 T3 post-HT. Barrier layer 6 is preferably of or includes silicon oxide, silicon nitride, silicon oxynitride, and / or the like, although other barrier materials can also be used. Unexpectedly, it has been found that the use of silicon oxide as a barrier layer 6 (compared to silicon nitride) often leads to improved optical results of the final product after heat treatment such as higher transmission. Any of said materials of the barrier layer 6 can be doped (for example, 0.5 to 15%) with Al, stainless steel or any (any) other metal (s) in certain embodiments herein. invention. The barrier layer (s) 6 is (are) formed on the glass substrate 1 by spraying or by any other appropriate technique. Barrier layer 6 may be about 10 to 1,000 A thick in certain exemplary embodiments, more preferably 50 to 500 A thick, and more preferably 50 to 200 A thick.

The inclusive DLC layer 11 may be approximately 5 to 1,000 angstroms (A) thick in certain exemplary embodiments of the present invention, more preferably 10-300 A thick and more preferably 10-300 A thick. thickness from 45 to 65 A. In certain exemplary embodiments of the present invention, the DLC layer 11 may have an average hardness of at least about 10 GPa, more preferably at least about 20 GPa, and more preferably about 20-90 GPa. Such hardness renders the layer (s) 11 resistant to scratches, certain solvents and / or the like. Layer 11 may, in certain exemplary embodiments, be of or include a special type of DLC known as highly tetrahedral amorphous carbon (t-aC) and may be hydrogenated (t-aC: H) in certain modes of realization. In certain hydrogenated embodiments, the t-aC type of DLC may include 1 to 30% hydrogen, more preferably 5-20% H and more preferably 10-20% H. This t-aC type of DLC includes more carbon-carbon sp bonds³ (C - C) what carbon - carbon sp bonds² (C - - C). In certain exemplary embodiments, at least about 50% of the carbon-carbon bonds in the DLC layer 11 may be carbon-carbon sp bonds.³, more preferably at least about 60% of the carbon-carbon bonds in layer 11 may be carbon-carbon sp bonds³, and more preferably at least about 70% of the carbon-carbon bonds in layer 11 may be carbon-carbon sp bonds³. In certain exemplary embodiments of the present invention, the DLC may have an average density of at least about 2.4 g / cm³, more preferably at least about 2.7 g / cm³.

Exemplary linear ion beam sources that can be used to deposit the inclusive DLC layer 11 on substrate 1 include any of those listed in any of US Pat.^you 6,261,693, 6,002,208, 6,335,086, or 6,303,225 (all incorporated herein by reference). When using an ion beam source to deposit a layer (s) 11, hydrocarbon feedstock gas (s) can be used (e.g. C₂H₂), HMDSO or any other suitable gas in the ion beam source to cause the source to emit an ion beam towards the substrate 1 to form layer (s) 11. It is to be emphasized that the hardness and / or the layer density (s ) 11 can be adjusted by varying the ionic energy of the deposition apparatus.

The DLC layer 11 allows the coated article to be more scratch resistant than if the DLC 11 were not provided. It is to be emphasized that while the layer 11 is on the glass substrate 1 in certain embodiments of the present invention, a Additional layer (s) 6 may or may not be under layer 11 between substrate 1 and layer 11 in certain exemplary embodiments of the present invention. Thus, the term "on the substrate" used herein is not limited to being in direct contact with the substrate as still other layer (s) may be provided in between.

For example and without limitation, layer 11 of or including DLC ​​may be any of the inclusive DLC layers of any of US Pat.^you 6,592,993; 6,592,992; 6,531,182; 6,461,731; 6,447,891; 6,303,226; 6,303,225; 6,261,693; 6,338,901; 6,312,808; 6,280,834; 6,284,377; 6,335,086; 5,858,477; 5,635,245; 5,888,593; 5,135,808; 5,900,342; or 5,470,661 (all of these patents being hereby incorporated by reference) or alternatively it may be any other suitable type of DLC inclusive layer. The inclusive DLC layer 11 may be hydrophobic (high contact angle), hydrophilic (low contact angle), or none, in different embodiments of the present invention.

The sacrificial protective layer 17 is provided to protect the DLC layer 11 during HT. If layer 17 was not provided, the DLC would oxidize considerably during HT and burning, thus rendering the final product defenseless against scratches. However, the presence of the sacrificial protective layer 17 prevents or reduces the amount of oxygen that the DLC 11 can reach during HT from the surrounding atmosphere, thereby preventing the DLC from being considerably oxidized during HT. Consequently, after HT, the DLC inclusive layer 11 remains on the glass substrate 1 to provide scratch resistance and / or the like.

The use of zirconium nitride (eg, ZrN) in the sacrificial barrier layer 17 has been surprisingly found to be especially advantageous with respect to reducing and / or preventing oxygen diffusion to DLC 11 during HT. The sacrificial barrier layer 17 of or including zirconium nitride may have a thickness of about 300 to 600 A in certain exemplary embodiments of the present invention, more preferably a thickness of 450 to 480 A. Zirconium nitride is a very dense material and provides an excellent barrier against oxygen diffusion to the DLC during HT.

In certain exemplary embodiments of the present invention, the zirconium nitride layer 17 may have a density of at least 6 g / cm³, more preferably at least 7 g / cm³. Also, in certain modes

In ES 2 328 040 T3 exemplary embodiment, the zirconium nitride layer 17 may have a mean hardness of at least 650 kgf / mm, more preferably at least 700 kgf / mm, and / or may have a population of Bond overlap of at least 0.25 (more preferably at least 0.30) for strength reasons. In certain exemplary cases, many of the Zr-N bonds in layer 17 are of the covalent type, which are stronger than ionic bonds, for reasons of strength. It should also be noted that in certain exemplary embodiments of the present invention, the ZrN in layer 17 may have a melting point of at least 2,500 degrees C, and may be approximately 2,980 ° C in certain cases at example title.

The zirconium nitride in layer 17 may or may not be doped with other material (s) in different embodiments of the present invention. In certain exemplary embodiments of the present invention, the zirconium nitride in layer 17 is not doped with any other material. However, in other exemplary embodiments of the present invention, the zirconium nitride in layer 17 may be doped with Cu and / or Ni (eg, about 0-15%, more preferably 1- 10% approximately) to provide greater stability and / or strength. The presence of a dopant such as Cu and / or Ni in ZrN can help make ZrN more stable during HT and can, for example, prevent or reduce phase changes (for example, a change to ZrO) of ZrN during HT. Furthermore, in certain exemplary cases, the Ni dopant in the ZrN layer 7 can serve as an oxygen-absorbing compound in the ZrN layer, thereby allowing the layer 7 to better function as an oxygen barrier, preventing or reducing diffusion of oxygen to DLC 11 during HT.

In certain exemplary embodiments of the present invention, the zirconium nitride in layer 17 can be represented by Zr_xN_Y, where the x: y ratio is 0.8 to 1.2 and is preferably about 1.0 in certain exemplary embodiments.

In other exemplary embodiments of the present invention, the Zr in layer 17 may be substituted for Cr (or NiCr). Thus, in such embodiments, layer 17 may comprise CrN, where this CrN layer may or may not be doped with Ni or the like in the manner and with the amount (s) explained above.

An exemplary process of manufacturing a window unit or the like is now described with reference to Figs. 2-3. Initially, as shown in Fig. 2 (a), the glass substrate 1 is provided and at least one barrier layer 6 (for example silicon oxide, silicon nitride, silicon oxynitride or the like) is sprayed on a surface of the same. Optionally, a multilayer solar control coating (not shown) can be deposited (eg by spraying) on ​​the surface of the glass substrate 1 opposite the barrier layer 6. As shown in Fig. 2 (b), it is deposited (eg by ion beam deposition) at least one layer 11 of or including DLC ​​in the glass substrate 1 over at least the barrier layer 6. Next, as shown in Fig. 2 (c), a protective layer 17 is deposited on the substrate 1 over the inclusive DLC layer 11. The protective layer 17 may be deposited by spray, CVD, ion beam deposition, or any other suitable technique. In an exemplary embodiment of the present invention, protective layer 17 may be of or include zirconium nitride as discussed above.

While layer 17 may comprise zirconium nitride in certain embodiments, the present invention is not limited thereto. Alternatively, instead of zirconium nitride, layer 17 may be of or include one or more of: chromium nitride, nickel-chromium nitride, amorphous silicon, silicon nitride, silicon oxide, silicon oxynitride, BC_x (boron carbide where x is 0.75 to 1.5), TiC_x (titanium carbide, where x is between 0.47 to 0.99 - it can be resistant to oxidation), HfC_x (hafnium carbide, where x is between 0.47 and 0.99) Ti_xHf_YC (titanium hafnium carbide, where in certain non-limiting examples x can be about 0.6 and y can be about 0.4), TaCx (tantalum carbide, where x is 0.47 and 0.99), ZrC_x (zirconium carbide, where x is between 0.47 and 0.99), Cr, NiCr, NiCrO_x, Ti, a removable suspension of magnesium oxide and / or TiOx. Some of these other materials are mentioned in related US Patent Application No. 10 / 091,589, filed March 7, 2002, the disclosure of which is incorporated herein by reference.

Optionally, a thin protective layer, comprising DLC ​​or the like (not shown) can be provided over the sacrificial layer 17 prior to the HT, to prevent the layer 17 from peeling off too early (i.e., to prevent the sacrificial layer 17 from peeling off before HT or during early HT stages). An example of such a protective layer (not shown) is a thin layer of DLC approximately 10-30 A thick, or any other suitable material that can burn during HT or can be easily removed after HT. Such a thin layer of DLC (not shown) on sacrificial layer 17 would burn rapidly during HT.

As shown in Fig. 2 (c) the glass substrate 1 with at least layers 6, 11 and 17 therein are heat treated (HT) below for purposes of heat tempering, heat bending, heat reinforcement and / or or similar. At least part of this HT can be carried out, for example, in an atmosphere including oxygen as is known in the art at temperature (s) between 550 and 800 degrees C, more preferably between 580 and 800 degrees C (ie i.e. temperature (s) above the DLC burn temperature). The HT may last at least 1 minute, more preferably from 1-10 minutes in certain non-limiting exemplary embodiments of the present invention. During HT, the presence of protective layer 17 protects the DLC-inclusive layer 11 of HT and prevents layer 11 from burning due to major oxidation. While in some cases some of the layer 11 may burn during HT, most if not all of the inclusive DLC layer remains on substrate 1 even after HT due to the presence of protective layer 17.

ES 2 328 040 T3

A significant advantage associated with the use of zirconium nitride in layer 17 is its ease of removal after HT. Protective layers like silicon nitride are sometimes undesirable as they require a complex pickling for removal after HT. On the other hand, it has been discovered that when layer 17 is made of zirconium nitride, layer 17 tends to start to peel on its own and / or to be removed after HT. Zirconium nitride layer 17 is believed to be so easy to remove from DLC 11 after HT due to the stresses associated with layer 17 and the thermal mismatch between layers 11 and 17. In particular the intrinsic compressive stress of the layer 17 of zirconium nitride, in combination with the thermally induced stress therein in the same direction, causes delamination of layer 17 to occur either automatically or easily after HT.

Removal of the zirconium nitride layer 17 from the DLC after HT can be accomplished by rubbing the coated article with Winder ™, water, alcohol, a solution including ammonium hydroxide, and / or the like. Friction with such liquids can be especially advantageous in removal of layer 17 after HT when the coated article is still hot from it (for example, when layer 17 is about 80-200 degrees C, more preferably about 100 degrees Celsius). -180 degrees C).

After removal of layer 17, the remaining coated article is shown in Fig. 3 and includes an outer layer comprising scratch resistant DLC. The processes mentioned above are advantageous in that they provide a technique that allows a coated article including a protective DLC inclusive layer to be heat treated without burning of the DLC layer during such HT. In other words, it is possible to provide a protective DLC inclusive layer 11 in a product in a commercially acceptable manner.

In accordance with certain exemplary embodiments of the present invention, coated articles herein lose no more than about 15% of their visible transmission due to HT, more preferably no more than about 10%. Furthermore, the monolithic coated articles herein preferably have a visible transition after HT of at least about 70%, more preferably at least about 75%. As an example, a visible transmission of a monolithic coated article can drop from about 85% to about 78% due to HT.

The coated article of Fig. 3 can be used in various applications including but not limited to IG window units, laminated vehicle windshields, other types of vehicle windows, furniture applications and / or the like. As an example, the coated article of Fig. 3 can be used in an IG window unit (insulating glass) as shown in Fig. 4.

The IG window unit of Fig. 4 includes a first glass substrate 1 and a second glass substrate 3 that are sealed together and / or are spaced from each other by one or more gaskets / spacers 5. The defined gap or gap 7 between the opposing substrates 1 and 3 it may or may not be filled with gas (eg Ar) and / or emptied at a pressure below atmospheric in different embodiments of the present invention. The glass substrate (s) 1 and / or 3 may be sodium-calcium silica glass (for example made by the known floating process) or any other suitable type of glass (for example, borosilicate glass) in different embodiments of the present invention. Each substrate 1, 3 may be approximately 1 to 10 mm thick, more preferably 2 to 5 mm thick, and more preferably approximately 2.5 to 3.6 mm thick in certain embodiments. by way of example of the present invention.

Still referring to Fig. 4, optionally, substrate 1 and / or 3 may have a solar control coating (eg, multi-layer low-emissivity coating) (not shown) provided on an interior surface thereof facing the another substrate. For example and without limitation, the solar control coating can include any of the coatings in any of US Pat.^you 5,688,585, 5,557,462, 4,898,790, 5,514,476, 3,682,528, 5,376,455, 5,377,045, 5,514,476, 5,770,321, 5,902,505, 5,942,338, 6,059,909, 6,060. 178, 6,132,881 or 6,159,607, or US serial number 09,794,224 (see WO 02/04375), all of which are hereby incorporated herein by reference. Many of these solar control coatings include at least one (and sometimes multiple) IR reflection layer (eg, including or including Ag and / or NiCr) sandwiched between a pair of dielectric layers; where the dielectric layers may or may not contact the Ag or NiCr. However, the present invention is not limited in such a way and any other type of solar control coating can be used instead in different cases. In certain exemplary embodiments of the present invention, the IG window unit of Fig. 4 has a visible transmission of at least 50%, more preferably at least 60%, and in some cases at least 50%. 70%.

Example

For purposes of example, and without limitation, the following exemplary coated article was made and tested in accordance with an exemplary embodiment of the present invention. A silicon nitride barrier layer 6 of a thickness of approximately 100 A, a layer 11 of DLC (type ta-C: H) of a thickness of approximately 70 A and a sacrificial protective ZrN barrier layer 17 of a thickness of approximately 460 A were deposited on a sodium-calcium silica glass substrate 1 as shown in Fig. 1. Before heat treatment, the coated article had a visible transmission greater than 80%. The coated article was then heat treated at a temperature of approximately 625 degrees C. As a result of this heat treatment, the sacrificial ZrN layer 17 began to delaminate from the DLC 11 on its own due to both intrinsic stress and induced thermal mismatch. . Layer 17 was then removed using a paper towel and Windex. The visible transmission of

ES 2 328 040 T3 monolithic coated article after heat treatment and after removing layer 17 was as high as about 78%. The scratch load for the sample was greater than 50 lbs, although it may be less than this in certain embodiments.

Finally, it is to be emphasized that an XPS diagram (not shown) has indicated that as a result of HT, Si and N of a silicon nitride barrier layer 6 can migrate to DLC layer 11 at least in an interface portion of the same, as well as some oxygen. However, it is not particularly troublesome as only small amounts of oxygen are involved. Furthermore, after HT, there is typically no trace of Zr on the DLC surface after the removal of ZrN mentioned above.

While the invention has been described in connection with what are presently considered to be the preferred and most practical embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but rather is understood covering various modifications and equivalent provisions included within the spirit and scope of the appended claims.