Method of making heat treated coated article using diamond-like carbon (dlc) coating and protective film

(54) Title: METHOD FOR MANUFACTURING ARTICLE (57) Summary:

THERMAL TREATED COATING USING DIAMOND TYPE CARBON COATING (DLC) AND PROTECTIVE FILM.

(30) Unionist Priority: 29/01/2007 us 11/699, oso (73) Holder (s): Center Luxembourgeois de Recherches Pour Le Verre Et La Ceramique SA (CRVC), Guardian Industries Corp.

(72) Inventor (s): Herbet Lage, Jens-Peter Muller, Jiangping Wang, Máximo Frati, Nestor P. Murphy, Rudolph Hugo Petrmichl (74) Attorney (s): Dannemann, Siemsen, Bigler & Ipanema Moreira (86) Request International: pct US2008000017 of 03/01/2008 (87) International Publication: wo 2008 / 094382of 07/08/2008

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DESCRIPTION REPORT FOR THE METHOD

TO MANUFACTURE THERMAL TREATED COATED ARTICLE

USING DIAMOND TYPE CARBON COATING (DLC) AND PROTECTIVE FILM.

The present invention relates to a method of manufacturing a heat-treated coated article (HT) for use in shower door applications, window applications, table top applications, or any other suitable application. For example, certain embodiments of this invention relate to a method for making a coated article including a heat treatment step of a glass substrate coated with at least one layer comprising diamond-like carbon (DLC) and a protective film overlying it. In certain exemplary embodiments, the protective film may be or may include zinc oxide. Following and / or during heat treatment (for example, thermal quenching, or the like) the protective film can be completely or partially removed. Other embodiments of this invention relate to the pre-HT coated article, or the post-HT coated article.

Background of the Invention

Coated articles, such as transparent shower doors and IG window units, are often heat treated (HT), as well as being thermally tempered, for safety and / or strength purposes. For example, coated glass substrates for use in shower doors and / or window units are often heat treated at elevated temperature (s) (for example, at least about 580 degrees C, more typically about 600 -650 degrees C for tempering purposes.

Diamond-like carbon (DLC) is sometimes known for its scratch-resistant properties. For example, different types of DLC are described 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 hereby incorporated by reference.

Sometimes it would be desirable to provide a window unit or other glass article with a protective coating including DLC ​​to protect it from scratches and the like. Unfortunately, DLC tends to oxidize and burn at temperatures of approximately 380 to 400 degrees C, when heat treatment is typically conducted in an atmosphere including oxygen. Thus, it will be appreciated that DLC as a protective overcoat 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, glass table tops , and / or the like.

Consequently, those skilled in the art will appreciate that a need in the art exists for a method of providing heat-treated (HT) coated articles with a protective coating (one or more layers) comprising DLC. A need for corresponding coated articles, both heat-treated and pre-HT, also exists.

Brief Summary of Examples of the Invention

Certain exemplary embodiments of this invention relate to a method for making a coated heat treated (HT) article for use in shower door applications, window applications, table top applications, or any other suitable application. For example, certain embodiments of this invention relate to a method for making a coated article including a heat treatment step of a glass substrate coated with at least one layer comprising diamond-like carbon (DLC) and a protective film overlying it. In certain exemplary embodiments, the protective film may be or may include zinc oxide. Following and / or during heat treatment (for example, thermal quenching, or the like) the thermal film can be completely or partially removed. Other embodiments of this invention relate to the pre-HT coated article, or the post-HT coated article.

In certain exemplary embodiments of this invention, at that point there is provided a method for making a heat-treated coated article, the method comprising: providing a glass substrate; forming at least one layer comprising diamond-like carbon (DLC) on the glass substrate; forming a protective film comprising zinc on the glass substrate over at least the layer comprising DLC; thermally treat the glass substrate with the layer comprising DLC ​​and the protective film, which comprise zinc in it so that during the heat treatment the protective film prevents significant dissipation of the layer comprising DLC, where the heat treatment comprises heating the substrate glass at a temperature (s) sufficient for thermal quenching, thermal strengthening, and / or thermal bending; and removing at least part of the protective film comprising zinc during and / or after said heat treatment.

In other exemplary embodiments of this invention, there is provided at that point a method for making a heat-treated coated article, the method comprising: providing a glass substrate; forming at least one layer comprising carbon on the glass substrate; forming a protective film comprising zinc on the glass substrate over at least the layer comprising carbon; thermally treat the glass substrate with the layer comprising carbon and the protective film comprising zinc in it, so that during heat treatment the protective film prevents significant dissipation of the layer comprising carbon, where the heat treatment comprises heating the substrate of glass at a temperature (s) sufficient for thermal quenching, thermal strengthening, and / or thermal bending; and removing at least part of the protective film comprising zinc during and / or after said heat treatment.

In yet other exemplary embodiments of this invention, a coated article is provided at that point comprising: a glass substrate that supports at least one layer comprising diamond-like carbon (DLC); a protective film comprising zinc oxide on the glass substrate over at least the layer comprising DLC; and where the protective film comprising zinc oxide is graded by oxidation so that the protective film is more oxidized (oxidized) at a location beyond the layer comprising DLC ​​than at a location closer to the layer comprising DLC.

Brief Description of Drawings

Figure 1 is a schematic cross-sectional view of a coated article, before and after heat treatment, according to an example embodiment of this invention.

Figure 2 is a schematic cross-sectional view of a coated article, before and after heat treatment, according to another example embodiment of this invention.

Figure 3 is a schematic cross-sectional view of a coated article, before and after heat treatment, according to another example embodiment of this invention.

Detailed Description of Example Modes of the Invention

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

Certain exemplary embodiments of this invention relate to methods for making coated articles that can use heat treatment (HT), wherein the coated article includes a coating (one or more layers) including diamond-like carbon (DLC). In certain cases, the HT may involve heating a support glass substrate, with the DLC on it, at a temperature (s) of 550 to 800 degrees C, more preferably from 580 to 800 degrees C (which is well above the temperature of burning DLC). In particular, certain exemplary embodiments of this invention refer to a technique for allowing the DLC to withstand such HT without significantly burning during it. In certain embodiments, a sacrificial protective film is formed on the glass substrate on the DLC to reduce the likelihood that the DLC will burn during HT. In this way, most (if not all) of the DLC remains on the glass substrate, and does not burn, during HT. Following HT, the sacrificial protective layer may or may not be removed in different embodiments of this invention.

Figure 1 is a schematic cross-sectional view of a coated article, before and after heat treatment, according to an example embodiment of this invention. Typically, the coated article on the left side of figure 1 exists during a manufacturing stage before heat treatment (HT), but there may also be post-HT in certain examples. The coated article shown in figure 1 includes glass substrate 1, layer 11 including DLC, and sacrificial protective film 17 which can include one or more layers. In certain exemplary embodiments, the protective film 17 includes first and second layers 17a and 17b which can be of the same or different material (s).

The glass substrate 1 is typically of or includes soda-lime glass, although other types of glass may be used in certain examples.

Layer 11 including DLC ​​may be about 5 to 1,000 Angstroms (A) thick in certain exemplary embodiments of this invention, more preferably 10-300 Å thick, and more preferably 20 to 65 Å thick, possibly of about 25-50 µm thick, with an example thickness being about 30 Angströns. In certain exemplary embodiments of this invention, the DLC layer 11 can have an average hardness of at least about 10 GPa, more preferably at least about 20 GPa, and preferably of about 20-90 GPa. Such hardness makes ( s) scratch resistant layer (s), 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-CA), and may be hydrogenated (t-aC: H) in certain embodiments. In certain hydrogenated embodiments, the type of t-aC or any other suitable type of DLC may include from 1 to 30% hydrogen, more preferably from 5 to 20% H, and most preferably from 10 to 20% H. This t-CA type of DLC includes more sp connections³ carbon-carbon (C - - C) than sp bonds² carbon - carbon (C - - C). In certain example embodiments, at least about 30% or 50% of the carbon-carbon bonds in the DLC layer 11 can be sp³ carbon 6 carbon (C - - C), more preferably at least about 60% of the carbon-carbon bonds in layer 11 can be sp³ carbon - carbon (C - - C), and preferably at least about 70% of the carbon-carbon bonds in layer 11 can be sp³ carbon carbon (C - - C). In certain exemplary embodiments of this invention, the DLC can have an average density of at least about 2.4 gn / cm³, more preferably at least about 2.7 gn / cm³. Examples of linear ion beam sources that can be used to deposit the exclusive DLC layer 11 on substrate 1 include any of those in any of US Patent Nos. 6,261,693, 6,002,208, 6,335,086, or 6,303,225 ( all incorporated by reference here). When using an ion beam source to deposit layer 11 (s), the hydrocarbon feed charge gas (for example, C2H2), HMDSO, or any other suitable gas, can be used in the beam source ion to cause the source to emit an ion beam onto substrate 1 to form layer (s) 11. It is noted that the hardness and / or density of layer (s) 11 can be adjusted (s) by varying the ion energy of the deposition apparatus.

The DLC 11 layer allows the coated article to be more resistant to scratching than if DLC 11 was not provided. It is noted that while layer 11 is over glass substrate 1 in certain embodiments of this invention, the additional layer (s) may or may not be below layer 11 between the substrate 1 and layer 11 in certain exemplary embodiments of this invention. Thus, the phrase on the substrate, as used here, is not limited to being in direct contact with the substrate since another layer (s) can still be provided between it.

For example, and without limitation, layer 11 of or including DLC ​​can be any of the inclusive DLC layers of any of US Patent Nos. 6,592,993, 6,592,992, 6,531 .182, 6,461 .731, 6,447,891, 6303,226 , 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 thereby being incorporated herein by reference), or alternatively may be any other suitable type of inclusive DLC layer. The inclusive DLC layer 11 can be hydrophobic (high contact angle), hydrophilic (low contact angle), or neither, in different embodiments of this invention.

The sacrificial protective film 17 is provided to protect the DLC layer 11 during HT. If film 17 is not supplied, DLC 11 would oxidize significantly during HT and burn, thereby rendering the final product defenseless against scratches. However, the presence of a sacrificial protective film 17 prevents or reduces the amount of oxygen that can reach DLC 11 during the HT of the surrounding atmosphere, thereby preventing the DLC from oxidizing significantly during HT. As a result, after HT, the inclusive layer of DLC 11 remains on the glass substrate 1 to provide scratch and / or similar resistance.

It was surprisingly found that the use of zinc and / or zinc oxide in sacrificial protective film 17 is especially beneficial with respect to reducing and / or preventing oxygen diffusion in the DLC during HT. In the exemplary embodiment of this invention of figure 1, the protective film 17 includes a first zinc incius layer 17a and a second inclusive zinc oxide layer 17b. The first inclusive zinc layer 17a can be metallic, substantially metallic, or substoichiometric zinc oxide in different exemplary embodiments of this invention; whereas the second inclusive zinc oxide layer 17b may be of or including zinc oxide in certain exemplary embodiments of this invention. In certain example embodiments, layer 17a is more metallic than layer 17b. In other words, layer 17b contains more oxygen than layer 17a.

In certain exemplary embodiments of this invention, layer 17a may be of or include ZnO_y and layer 17b can be of or include ZnO_x, where x&gt; y (that is, layer 17b contains more oxygen than layer 17a). In addition, in certain exemplary embodiments of this invention, y is about 0 to 0.9, more preferably about 0.1 to 0.9, even more preferably about 0.1 to 0.8, and possibly about 0.1 to 0.7. Meanwhile, in certain exemplary embodiments of this invention, x is greater than y, and x is about 0.3 to 1.0, more preferably about 0.3 to 0.99, even more preferably about 0.5 to 0.95, and possibly about 0.6 to 0.90. Thus, it will be appreciated that in certain example cases, both layers 17a and 17b may be of or include zinc oxide, and both layers 17a and 17b may be substoichiometric.

Advantageously, it has been found that the use of the zinc oxide layer 17a which is more metallic than the zinc oxide layer 17b surprisingly allows for more efficient and easier removal of the protective film 17 during and / or after heat treatment ( HT). Different compositions of inclusive zinc oxide layers 17a and 17b are used to cause different stresses in layers 17a and 17b, the stresses of which are manipulated to allow film 17 to be more easily removed during and / or after HT. In particular, the more metallic zinc oxide based layer 17a can optionally be considered a release layer to allow film 17 to be easily removed from the DLC or substrate during and / or after HT due to its reduced oxygen content or no content of oxygen, whereas the less metallic (and more oxidized) zinc oxide based layer 17b can be considered an oxygen blocking layer that reduces or prevents the DLC from burning and / or oxidizing during HT. It is also noted that any absorption layer can be considered an oxygen barrier layer in certain example cases. In certain example cases, the more oxide layer 17b can be considered a blocking / protection layer, to protect the softer less oxide absorption / barrier layer 17a during heat treatment and otherwise. Zinc oxide is a highly advantageous material for film 17 because it can be easily removed (for example, using water and / or vinegar) during and / or after HT in a non-toxic manner. In addition, metallic Zn and / or zinc oxide are also highly advantageous for use in protective film 17 because the Zn in film 17 acts as an oxygen absorber during

HT, thereby preventing or reducing the likelihood of the DLC burning during such HT. In certain exemplary embodiments, during oxidation at elevated temperature, the resulting oxide film protects the more metallic film 17a from further oxidation; the inclusive zinc layer 17a which is more metallic has a greater potential increase in volume due to oxidation than does a more oxidized zinc oxide layer, and such an increase in volume (for example, during quenching) results in an increase in tension which allows for more efficient / easier film removal.

As noted above, one or both layers 17a and 17b when of or including zinc and / or zinc oxide are sub-stoichiometric. This is advantageous for oxygen absorption purposes during HT. If the zinc oxide in the entire film 17 is also oxidized (i.e., completely stoichiometric) before HT, then oxygen can diffuse through zinc oxide. However, the substoichiometric nature of the layer (s) 17a and / or 17b allows the zinc in it to absorb oxygen during HT, so that at least layer 17a (and possibly layer 17b) does not burn during HT. It is noted that the top zinc oxide based layer 17b may or may not burn (completely or partially) during HT in different exemplary embodiments of this invention. It is noted that another example advantage of sub-stoichiometric zinc oxide (compared to completely stoichiometric zinc oxide) is that it can be deposited (for example, by spraying or the like) more quickly. One or both layers 17a, 17b can be deposited by spraying in a substoichiometric form, in any suitable manner, for example, by varying the flow of oxygen gas in the spraying chamber. For example, as a non-limiting example, layer 17a can be deposited by spraying using 10 ml / kW (relative to the oxygen gas flow content), whereas layer 17b can be deposited by spraying using 12 ml / kW ( with the rest of the gas being Ar or similar) in example cases.

Note that one or both of the zinc oxide layers 17a and 17b can be doped with other materials such as Al, N, Zr, Ni, Fe, Cr,

Ti, Mg, mixtures of these, or the like, in certain exemplary embodiments of this invention.

In certain exemplary embodiments of this invention, layer 17a (for example, zinc or substoichiometric zinc oxide) can be deposited (for example, by spraying) to be about 500 - 20,000 µ thick, more preferably about from 2,000 - 15,000 µ thick, even more preferably from about 2,000 - 10,000 µ thick, with an example densities of about 8,000 µ. In certain embodiments, the inclusive zinc oxide layer 17b can be deposited (for example, by spraying) to be about 200 - 10,000 Šin thickness, more preferably about 500 - 5,000 Šin thickness, more preferably about 1,000 - 3,000 Å thick, with an example densities being around 2,000 Å. The more metallic layer 17a is thicker than the less metallic layer 17b in certain exemplary embodiments of this invention; layer 17a can be at least twice as thick as layer 17b in certain example cases before HT.

Figure 2 illustrates another example embodiment of this invention. The embodiment of figure 2 is the same as the embodiment of figure 1 described above, except that in the embodiment of figure 2 a barrier layer 6 is provided between the glass substrate 1 and the inclusive layer DLC 11. The barrier layer 6 can be a dielectric in certain exemplary embodiments of this invention. The optional barrier layer 6 is to prevent or reduce sodium and / or oxygen (Na) from migrating from glass 1 in DLC 11 during HT. In this respect, such an optional barrier layer 6 can improve the overall optical characteristics of the post-HT coated article. The barrier layer 6 can be of or can include silicone oxide, silicone nitride, silicone oxinitride, and / or the like, although other barrier materials can also be used. The barrier layer (s) 6 is (are) formed on the glass substrate 1 by spraying, or by any other suitable technique. The barrier layer 6 can be about 10 to 1,000 µm thick in certain example embodiments, more preferably 50 to 500 µm thick, and preferably from 50 to 200 µm thick.

Figure 3 illustrates another example embodiment of this invention. The figure 3 mode is the same as the figure 1 mode (or even the figure 2 mode if barrier layer 6 is used, which may be the case in the figure 3 mode) except that, instead of two discrete layers 17a and 17b, the protective film 17 is made of a layer that is graduated by oxidation (continuously or not continuously) by its densities. In the embodiment of figure 3, the film 17 is supplied in such a way that the film 17 includes more oxygen in one location beyond the DLC layer 11 than in another location in the film closest to the DLC layer

11. It is noted that the film 17 in the modalities of figure 1-2 can also be considered graded by oxidation because the entire film 17 is more oxidized in layer 17b in addition to DLC 11 than in layer 17a closest to DLC 11. However, in In the embodiment of figure 3, it is also possible that the grading by continuous or substantially continuous oxidation occurs through the entire film 17 or substantially whole in certain example cases.

An example process for making a coated article will now be described with reference to figures 1 to 3. Initially, the glass substrate 1 is provided, and at least one barrier layer 6 (for example, silicone oxide, silicone nitride , silicon oxynitride, or the like) can optionally be sprayed onto a surface of it. Optionally, a multilayer solar control coating (not shown) can be deposited (for example, by spraying) on ​​the surface of the glass substrate 1 opposite barrier layer 6. At least one layer 11 of or including DLC ​​is deposited ( for example, by ion beam deposition) on the glass substrate 1, on at least the optional barrier layer 6 if present. Then, the protective film 17, for example, including layers 17a and 17b, is deposited on substrate 1 on the inclusive layer of DLC 11. The protective film 17 can be deposited by spraying, CVD, ion beam deposition, or any another suitable technique. Optionally, a thin protective layer comprising DLC, silicon nitride, aluminum nitride, or silicone aluminum nitride (not shown), can be provided over the sacrificial film 17 before HT, for durability and / or barrier purposes of oxygen.

As shown in figures 1 and 2, the glass substrate 1 with films 6 (optional), 11 and 17 in it is then heat treated (HT) for purposes of thermal quenching, thermal bending, thermal strengthening, and / or the like. At least part of this HT can be administered, for example, in an atmosphere including oxygen as known in the art at temperature ^) from 550 to 800 degrees C, more preferably from 580 to 800 degrees C (i.e., temperature (s) above firing temperature). The HT can last for at least one minute, more preferably from 1 to 10 minutes, in certain non-limiting exemplary embodiments of this invention. During HT, the presence of protective film 17 protects the inclusive layer of HT 11 DLC and prevents layer 11 from significantly oxidizing and / or burning due to significant oxidation during HT. While, in some cases, a little of layer 11 can burn during HT, most if not all inclusive layers of DLC 11 remain on substrate 1 even after HT due to the presence of the protective film 17.

A significant advantage associated with the use of zinc and / or zinc oxide in film 17 is its ease of removal after HT. Protective layers, such as silicone nitride, are sometimes undesirable since they require complex cauterization to remove the same after HT. On the other hand, it has been found that when film 17 is made of zinc and / or zinc oxide, soluble in vinegar and / or water (possibly only water without vinegar required in certain preferred embodiments), the application of vinegar and / or water allows portions of film 17 to remain after HT so that they are easily removed in a non-toxic manner. Again, in certain example embodiments, it is possible to remove zinc oxide with only water (no vinegar needed) in certain examples, which is advantageous from a cost and processing point of view. In certain example cases, rubbing with such liquids can be especially beneficial in removing film 17 after HT when the coated article is still hot in it (for example, when film 17 is at about 80 to 200 degrees C, more preferably from about 100 to 180 degrees C; although removal of the film 17 can also occur at room temperature in certain example embodiments).

After the film 17 has been removed, the remaining coated article is shown on the right side of figures 1 and 2, and includes an outer layer comprising scratch resistant DLC. The aforementioned processes are advantageous in that they provide a technique for allowing a coated article including an inclusive layer of protective DLC 11a to be heat treated without the DLC layer 11 burning during such HT. In other words, it is possible to provide an inclusive layer of protective DLC 11 in a thermally treated product (for example, thermally tempered) in a commercially acceptable manner.

According to certain exemplary embodiments of this invention, articles coated therein lose no more than about 15% of their visible transmission due to HT, more preferably no more than about 10%. In addition, the monolithic coated articles thereon preferably have a visible transmission after HT of at least about 50%, more preferably at least about 60 or 75%.

At the same time that the invention has been described in relation to what is now considered to be the most practical and preferred modality, it is to be understood that the invention will not be limited to the described modalities, however on the contrary, it is intended to cover various modifications and equivalent provisions included in the spirit and scope of the attached claims.