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

This application is a continuation application (CIP) US, reg. No. 11/699080, January 29, 2007, which is incorporated herein by reference.

Certain embodiments of the present invention relate to a method of producing heat treated (HT) coated articles for use in the shower doors, windows, table tops or any other suitable applications. For example, some embodiments of the present invention relate to a method for producing a coated article comprising a step of heat treatment of glass substrate coated with at least one layer comprising diamond-like carbon (DLC), and imposing on it a protective film. In certain exemplary embodiments the protective film may consist of or include both (a) an oxygen barrier or oxygen-impermeable layer, and (b) release layer. After and / or during heat treatment (e.g., thermal tempering or the like) the protective film may be completely or partially removed. Other embodiments of this invention relate to the pre-heat-treated coated article or heat-treated product is further coated.

BACKGROUND ART In the field of the invention

Coated articles such as transparent shower doors and glass are often heat treated (HT), such as thermal tempering, in order to secure and / or increase the strength. For example, coated glass substrates for use in shower door and / or insulating glass units are often heat treated at high temperatures (e.g., at least about 580 ° C, more typically about 600-650 ° C) in order to quench.

Diamond-like carbon (DLC) is sometimes known for its ability to resist scratching. Various types of DLC are discussed, for example, in the following US Patents: 6303226; 6303225; 6261693; 6338901; 6312808; 6280834; 6284377; 6335086; 5858477; 5635245; 5888593; 5135808; 5900342 and 5470661, each of which is incorporated herein by reference.

Sometimes it would be desirable to provide a window unit or other glass article with a protective coating comprising DLC, to protect it from scratches and the like. Unfortunately, DLC tends to oxidize and burn at temperatures of about 380-400 ° C, as the heat treatment is typically carried out in an atmosphere containing oxygen. Thus, it should be appreciated that DLC as a protective coating may not survive the heat treatment (HT) at the extremely high temperatures described above which are often required in the manufacture of car windows, insulated glass units, worktops and / or the like.

Accordingly, experts should be understood that in the art there is a need in the method of producing heat treated (HT) coated articles (one or more layers) comprising DLC. There is also a need for corresponding coated articles, both heat treated and pre-heat treated.

Brief description of the invention examples

Certain exemplary embodiments of the invention relate to a method of producing heat treated (HT) coated articles for use in the shower doors, windows, table tops or any other suitable applications. For example, some embodiments of the present invention relate to a method for producing a coated article comprising a step of heat treatment of glass substrate coated with at least one layer comprising diamond-like carbon (DLC), and imposing on it a protective film. In certain exemplary embodiments the protective film may be composed of or may include both (a) an oxygen barrier or oxygen-impermeable layer, and (b) release layer. After and / or during heat treatment (e.g., thermal tempering or the like) the protective film may be completely or partially removed. Other embodiments of this invention relate to the pre-heat-treated coated article or heat-treated product is further coated.

A typical advantage of using distinct and different from each other and release oxygen-barrier layers in the protective film is that each layer of the protective film can be optimized for its intended function. Consequently, there may be optimized improved characteristics of the protective film and can be made thinner if desired.

In some embodiments, given in each example of the present invention provides a method for producing a heat-treated coated article, the method comprising obtaining a glass base; forming at least one layer comprising diamond-like carbon (DLC), a glass base; forming a protective film on a glass base over at least the layer comprising DLC, wherein the protective film comprises a release layer and oxygen barrier layer, the release layer and oxygen barrier layer are made of different materials and / or have different stoichiometry; heat treated glass substrate with the layer comprising DLC ​​and the protective film thereon so that during the heat treating the protective film prevents significant burning layer comprising DLC, wherein the heat treatment comprises heating the glass substrate to a temperature sufficient for thermal tempering, heat strengthening and / or high temperature bending; and processing the protective film release liquid and removing at least a portion of the protective film during and / or after heat treatment.

BRIEF DESCRIPTION OF DRAWINGS

1 is a schematic sectional view of the coated articles before and after heat treatment, in accordance with one exemplary embodiment of the present invention.

2 is a schematic sectional view of the coated articles before and after heat treatment, in accordance with another exemplary embodiment of the present invention.

3 is a schematic sectional view of the coated articles before and after heat treatment, in accordance with another exemplary embodiment of the present invention.

4 is a schematic sectional view of the coated articles before and after heat treatment, in accordance with another exemplary embodiment of the present invention.

5 is a schematic sectional view of the coated articles before and after heat treatment, in accordance with another exemplary embodiment of the present invention.

6 is a schematic sectional view of the coated articles before and after heat treatment, in accordance with another exemplary embodiment of the present invention.

7 is a schematic sectional view of the coated articles before and after heat treatment, in accordance with another exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Referring now more particularly to the accompanying drawings, in which like numerals represent like parts throughout the several views.

Some exemplary embodiments of this invention relate to methods of producing coated products, which can be used in the heat treatment (HT), wherein the coated article includes a coating (one or more layers) comprising diamond-like carbon (DLC). In some cases, the HT may involve heating the supporting glass substrate, with the DLC thereon, to temperature of 550 to 800 ° C, more preferably from 580 to 800 ° C (well above temperatures burnout DLC). In particular, certain exemplary embodiments of the present invention relate to a method that allows to withstand such NT DLC without significant burn. In some embodiments, the glass base on top of DLC protective film is formed expended to reduce the probability of burnout DLC during HT. Thus, the majority (if not all) DLC remains on the glass base, and does not burn during HT. After HT consumable protective film (which may comprise one or more layers) can be removed or may not be deleted in other embodiments of this invention.

In certain embodiments consumed protective film may consist of or include both (a) an oxygen barrier or oxygen-impermeable layer, and (b) release layer. A typical advantage of using distinct and different oxygen-barrier and release layers in film 17 is that each layer (17a and 17b) can be optimized for its intended function. Consequently, there may be improved characteristics optimized consumable film 17 and can be made thinner if desired. In some exemplary embodiments, after HT layer comprising DLC, protects against abrasion and corrosion, as well as the adhesion of the hard water minerals (e.g., has good hard water cleaned).

1 is a schematic sectional view of the coated articles before and after heat treatment in accordance with one exemplary embodiment of the present invention. Typically, the coated article on the left of Figure 1 is available in the manufacturing stage before the heat treatment (HT), but in some cases may also exist after the additional heat treatment. The coated article shown in Figure 1 comprises a glass substrate 1, DLC-containing layer 11 and the consumable protective film 17 which may include one or more layers. In certain exemplary embodiments the protective film 17 includes first and second layers 17a and 17b, which may be of the same or different materials.

Glass substrate 1 typically consists of or includes soda-lime-silica glass, although in certain cases there may be other types of glass.

DLC-containing layer 11 may have a thickness of from about 5 to 1,000 angstroms (Å) in certain example embodiments of this invention, more preferably a thickness of 10-300 Å, and most preferably from 20 to 65 Å, possibly about 25-50 Å, for example, a typical thickness is approximately 30 angstroms. In certain embodiments of the present invention, DLC-layer 11 may have an average hardness of at least about 10 GPa, more preferably at least about 20 GPa, and most preferably from about 20-90 GPa. This makes the hardness layer 11 resistant against scratching, certain solvents, and / or the like. Layer 11 may, in some exemplary embodiments, consist of, or include a special type of DLC, known as high carbon tetrahedral amorphous carbon (t-aC), and in some embodiments, may be hydrogenated (t-aC: H). In some embodiments, the hydrogenated carbon t-aC or other suitable type of DLC may include from 1 to 30% hydrogen, more preferably 5-20% H, and most preferably 10-20% H. This t-aC type of DLC has more sp3 carbon -carbon (CC) bonds than sp2 carbon-carbon (CC) bonds. In certain embodiments, at least about 30% or 50% of carbon-carbon bonds in DLC-layer 11 may be sp3 carbon-carbon (CC) bonds, more preferably at least about 60% of carbon-carbon bonds in the layer 11 may be sp3 carbon-carbon (CC) bonds, and most preferably at least about 70% of carbon-carbon bonds in the layer 11 may be sp3 carbon-carbon (CC) bonds. In some embodiments, the DLC may have an average density of at least about 2.4 g / cm3, more preferably at least about 2.7 g / cm3. Example linear ion beam sources that may be used for the deposition of DLC-containing layer 11 on the base 1 include any of the patents US 6,261,693, 6,002,208, 6,335,086 or 6,303,225 (all incorporated herein by reference). When applying the source ion beam deposition layer (s) 11 in the source ion beams can be used a hydrocarbon feed gas (e.g., C2H2, HMDSO, or any other suitable gas) to cause the source to emit an ion beam toward substrate 1 for forming layer (s) 11 . It should be noted that the hardness and / or density of layer 11 may be adjusted by changing the ion energy deposition in the device.

DLC layer 11 allows the coated article to be more scratch resistant than if the DLC layer 11 was not. Note that, although in some embodiments, layer 11 is a glass base 1, in certain exemplary embodiments of the present invention, between the base 1 and the layer 11 under the layer 11 may or may not have an additional layer (s). Thus, the phrase "based on" as used herein is not limited by the availability of direct contact with the base, as between the two can still be provided another layer (s).

For example, and without limitation, the layer 11 consisting of or including DLC, may be any of the DLC-containing layers according to any one of US patents 6,592,993; 6592992; 6531182; 6461731; 6447891; 6303226; 6303225; 6261693; 6338901; 6312808; 6280834; 6284377; 6335086; 5858477; 5635245; 5888593; 5135808; 5900342 and 5470661 (all of these patents are incorporated herein by reference), or alternatively may be any other suitable type of DLC-containing layer. DLC-containing layer 11 may be hydrophobic (high contact angle), hydrophilic (low contact angle), or neither one nor the other, in other embodiments of the present invention. In certain embodiments of the present invention, DLC 11 may include (or exclude) about 5-30% Si, more preferably about 5-25% Si, and possibly about 10-20% Si. In certain cases, the DLC may also be hydrogen.

Consumable protective film 17 is provided to protect the DLC-layer 11 during HT. If the film 17 will not, DLC 11 can significantly oxidize during HT and burn, thereby making the final product defenseless against scratching. However, the presence of the protective film 17 consumed prevents or reduces the amount of oxygen from the ambient atmosphere, which can achieve DLC 11 during HT, thereby preventing substantial oxidation during HT DLC. As a result, after HT DLC-containing layer 11 remains on a glass base 1 to provide scratch resistance and / or the like. In some embodiments, the protective film 17 includes both an oxygen barrier, or oxygen barrier layer 17a, and the spacer layer 17b.

Surprisingly it has been found that the use zinc and / or zinc oxide consumed protective film 17 is particularly advantageous in terms of reducing and / or preventing oxygen diffusion into the DLC during HT. In an exemplary embodiment of the invention according to Figure 1 the protective film 17 comprises first layer 17a, the zinc and the second layer 17b, containing zinc oxide. The first zinc-containing layer 17a may be metallic, substantially metallic, or sub-stoichiometric zinc oxide in other exemplary embodiments of the present invention; while a second layer 17b, containing zinc oxide in certain example embodiments of this invention may consist of or include zinc oxide. In certain embodiments, layer 17a is more metallic than layer 17b. In other words, layer 17b contains more oxygen than layer 17a. Thus, layer 17a is able to act as a release layer, and the layer 17b is capable of acting as a barrier to oxygen or oxygen-impermeable layer. "Barrier" or "oxygen barrier" layer means that the layer does not allow a substantial amount of oxygen reached the DLC layer during HT.

In certain embodiments of the present invention, the layer 17a may consist of or include ZnOy, and the layer 17b may be composed of or include ZnOx, where x> y (i.e., layer 17b contains more oxygen than layer 17a). Furthermore, in some embodiments of the present invention, y is from about 0 to 0.9, more preferably from about 0.1 to 0.9, more preferably from about 0.1 to about 0.8, and possibly from about 0 1 to 0.7. Meanwhile, in some embodiments of the invention, x is greater than y, and x is from about 0.3 to 1.0, more preferably from about 0.3 to 0.99, even more preferably from about 0.5 to 0, 95, and possibly from about 0.6 to 0.90. Thus, it should be understood that in some typical cases, both layers 17a and 17b may consist of or include zinc oxide, and both layers 17a and 17b may be substoichiometric.

It has been found that the use of zinc oxide layer 17a that is more metallic than zinc oxide-containing layer 17b, unexpectedly advantageously allows for more efficient and easier removal of the protective film 17 during and / or after heat treatment (HT). In other words, layer 17a is a separating layer. Using different formulations containing zinc oxide layers 17a and 17b to cause different stresses in layers 17a and 17b, and the voltage is set so as to be able to easily remove the film 17 during and / or after HT. In particular, a metal layer 17a on the basis of zinc oxide can be considered as a release layer, which allows to easily remove the film 17 with DLC or base during and / or after HT due to its reduced oxygen content or absence of oxygen, whereas the less metallic (and more oxidized ) layer 17b on the basis of zinc oxide can be viewed as a barrier to oxygen or oxygen-impermeable layer which reduces or prevents burning and / or oxidation of the DLC during HT. Note also that in some specific cases, any getter layer may be considered as oxygen-impermeable layer. In some typical cases, more oxidized layer 17b may be considered as a barrier / protection layer, for protecting the softer less oxidized getter / barrier layer 17a during heat treatment and others. Zinc oxide is a highly advantageous material for film 17 because it can be easily and non-toxic remove (e.g., using water and / or vinegar) during and / or after HT.

As noted above, one or both layers 17a and 17b, when they consist of or include zinc and / or zinc oxide may be substoichiometric. This is advantageous in view of the absorption of oxygen during HT. If the zinc oxide film 17 as a whole is too oxidized (i.e., fully stoichiometric) prior to HT, then oxygen can diffuse through the zinc oxide. However, the substoichiometric nature of layer (s) 17a and / or 17b allows the zinc to absorb oxygen during HT, so that at least layer 17a (and possibly layer 17b) does not burn out during HT. It should be noted that, in various exemplary embodiments of the present invention, the upper layer 17b of zinc oxide can not scorch or burn (fully or partially) during HT. It should be noted that another characteristic advantage of substoichiometric zinc oxide (compared to fully stoichiometric zinc oxide) is that it can be applied (e.g., sprayed or the like) more quickly. One or both layers 17a, 17b may be applied by spraying in substoichiometric form any suitable manner, for example by changing the flow of gaseous oxygen in the spray chamber (s). For example, as one non-limiting example, in typical cases, layer 17a may be applied by spraying, using 10 ml / kW (based on the flow rate of oxygen gas), and the layer 17b may be applied by spraying, using 12 ml / kW (with the remaining gas is Ar or similar).

Note that in some exemplary embodiments of this invention, one or both layers 17a and 17b of the zinc oxide may be doped with other materials such as Al, N, Zr, Ni, Fe, Cr, Ti, Mg, mixtures thereof or the like.

In certain embodiments of the present invention, the spacer layer 17a (e.g., of zinc or substoichiometric zinc oxide) may be deposited (e.g., coated) to a thickness of about 50-20000 Å, more preferably a thickness of about 50-3000 Å, more preferably about 100 -1000 Å, and the characteristic thickness of about 100-300 Å. In some embodiments, the zinc oxide-containing layer 17b may be deposited (e.g., coated) to a thickness of about 200-10,000 Å, more preferably a thickness of about 500-5000 Å, more preferably about 1000-3000 Å, and the characteristic thickness is about 2000 Å . In certain embodiments of the present invention more metallic layer 17a may be thicker than less metallic layer 17b; In some typical cases before HT layer 17a may be at least twice as thick as layer 17b. The preferred thickness of the entire consumable film 17 in certain example embodiments is less than about 10000 Å, more preferably less than about 3000 Å, and most preferably less than about 1000 Å.

2 shows another exemplary embodiment of the present invention. The embodiment of Figure 2 is identical to the above embodiment of Figure 1, except that in the embodiment according to Figure 2 between the glass substrate 1 and DLC-containing layer 11 provides a barrier layer 6. The barrier layer 6, in some exemplary embodiments, of the present invention may be a dielectric. Additionally, the barrier layer 6 is for preventing or reducing the migration of oxygen and / or sodium (Na) glass 1 to the DLC 11 during HT. In this respect, such an additional barrier layer 6 may improve the overall optical characteristics of the additional heat treatment of the coated article. Barrier layer 6 may consist of or include silicon oxide, silicon nitride, silicon oxynitride and / or the like, although it can also be used, and other barrier materials. Barrier layer (s) 6 is formed on a glass base 1 by spraying or any other suitable method. In certain embodiments the barrier layer 6 may have a thickness of from about 10 to 1000 Å, more preferably from 50 to 500 Å, and most preferably from 50 to 200 Å. It should be noted that, if desired, a barrier layer (s) 6 may also be provided in other examples of embodiments of the invention, such as any of those shown in Figures 4-7, between the DLC 11 and the glass substrate 1.

3 illustrates another exemplary embodiment of the present invention. The embodiment of Figure 3 is identical to the embodiment according to Figure 1 (or even the embodiment of Figure 2, if a barrier layer 6 which may be the case in the embodiment according to Figure 3), except that instead of two separate layers 17a and 17b the protective film 17 is made of a single layer, which changes the degree of oxidation (continuously or non-continuously) through its thickness. In the embodiment of Figure 3 the film 17 is configured so that it contains more oxygen at a location more remote from the DLC-layer 11 than elsewhere in the film closer to the DLC-layer 11. Note that the film 17 in the embodiments according to Figures 1-2 can also be considered a film with a variable oxidation state, as a whole film 17 is oxidized in a layer 17b, which is located further from the DLC 11 than in layer 17a, which is closer to the DLC 11. However, in the embodiment of FIG .3 in some typical cases, it is also possible for continuous or substantially continuous change in the oxidation state throughout or substantially throughout the film 17.

Now with reference to Figures 1-3 will be described an exemplary method for producing the coated article. First take the glass substrate 1, and its surface may additionally be sprayed with at least one barrier layer 6 (e.g., silicon oxide, silicon nitride, silicon oxynitride, or the like). Additionally multilayer solar control coating (not shown) may be applied (e.g., sprayed) onto the surface of glass substrate 1 opposite the barrier layer 6. At least one layer 11 consisting of or including DLC, is deposited (e.g., ion beam deposition) on the glass base 1 over at least an additional barrier layer 6 if present. Then, the base 1 over DLC-containing layer 11 is applied to the protective film 17, for example, comprising layers 17a and 17b. The protective film 17 may be applied by spraying, chemical vapor deposition, ion beam deposition or any other suitable method. Additionally, a thin protective layer comprising DLC, silicon nitride, aluminum nitride or silicon-aluminum nitride (not shown) may be provided on consumable film 17 to HT, for durability and / or for oxygen impermeability.

As shown in Figures 1-2, then the glass substrate 1 with films 6 (optional), 11 and 17 thereon is then heat treated (HT) for the purpose of thermal tempering, bending at a high temperature, heat strengthening and / or the like. At least part of this HT may be conducted, for example, in an atmosphere containing oxygen, as known in the art at temperature (s) of from 550 to 800 ° C, more preferably from 580 to 800 ° C (i.e. at a temperature (s) above the melting burnout DLC). HT may last for at least one minute, more preferably 1-10 minutes, in certain example non-limiting embodiments of the present invention. During HT presence of protective film 17 protects DLC-containing layer 11 from the HT and prevents significant oxidation and / or burning layer 11 due to significant oxidation during HT. Although in some cases, part of layer 11 may burn during HT, most, if not all, DLC-containing layer 11 remains on the base 1 even after the HT due to the presence of the protective film 17.

A significant advantage associated with using zinc and / or zinc oxide in film 17 is its ease of removal after HT. Such protective layers as silicon nitride, is sometimes undesirable since they require complex etching in order to remove them 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 (in some preferred embodiments may require only water with no vinegar), the application of vinegar and / or water allows easy non-toxic and remove portions of the film 17 remaining after HT. Again, in certain example embodiments, in certain cases, the zinc oxide can be removed with water alone (no vinegar needed), which is advantageous in terms of cost and processability. In some specific cases may be particularly advantageous rubbing with a liquid for removing the film 17 after HT when the coated article is still warm enough after HT (e.g., when the temperature of the film 17 is about 80-200 ° C, more preferably 100-180 ° C , although certain exemplary embodiments of the removal of the film 17 may also take place at room temperature).

In the right part of Figures 1-2 shown a coated article remaining after the film 17 has been removed, and it comprises an outer layer comprising scratch resistant DLC. The above methods are advantageous in that they provide a method to carry out the heat treatment the coated article comprising a protective layer comprising DLC-11, without burning-DLC layer 11 during such HT. In other words, it becomes possible to obtain a protective layer 11 comprising DLC, on the heat-treated (e.g., thermal tempering), the product commercially acceptable manner.

4 shows a sectional view of an exemplary embodiment of the present invention, which is similar to Figures 1-2, except that release layer 17a and the oxygen barrier layer 17b need not be of zinc oxide. In the embodiment of Figure 4 a barrier layer 6 (discussed above) between the glass and the DLC can be provided or not provided (however, the figure it is not shown).

Oxygen barrier, or oxygen barrier layer 17b may be composed of or comprise material selected from the group consisting of zinc oxide, silicon carbide, aluminum nitride, boron oxide, aluminum oxide, aluminum oxynitride, silicon nitride, silicon oxide, silicon oxynitride and mixtures. Preferred materials for the oxygen blocking or oxygen-impermeable, layer 17b in certain example embodiments are aluminum nitride and silicon carbide. In certain embodiments, the layer 17b is made approximately as strong and / or durable as glass.

Releasable layer 17a may be any suitable material that is soluble in or readily reacts with water, vinegar, or bleach. Release layer 17a preferably has a melting temperature (or decomposition temperature) above 580 or 600 ° C in certain example embodiments. Release layer 17a may be composed of or include oxides, suboxides, nitrides and / or subnitrides of boron, titanium boride, magnesium, zinc and mixtures thereof. In certain embodiments preferred materials for releasably layer 17a are suboxides of zinc, magnesium and / or titanium boride. Note that the term "oxide" used here widely covering suboxides.

In some exemplary embodiments, the release layer 17a is more soluble in water, vinegar, bleach and / or the like than the layer 17b. Moreover, in certain example embodiments, oxygen barrier layer 17b more impervious to oxygen and / or is harder than the release layer 17a. Typical DLC coating can provide high quality after additional heat treatment and subsequent removal of the film, with good scratch resistance and good hard water cleanability. In various embodiments of the present invention, release layer 17a and / or the oxygen barrier layer 17b may be applied by sputtering or other suitable method.

5 shows an example embodiment where the release layer 17a is composed of or includes a suboxide of magnesium (MgOh) and oxygen barrier, or oxygen barrier layer 17b is composed of or includes silicon carbide. Additionally, in some cases, this embodiment can provide a barrier layer 6 between the DLC 11 and the glass substrate 1 to reduce sodium migration during or due to HT. After heat treatment or HT (e.g., annealing) the product is exposed to a mildly reactive liquid (e.g., water, vinegar, dilute ammonia and / or bleach), and the liquid penetrates through the release layer 17a on the microchannels or grain boundaries in the overlying layer (s ) and causes the discharge of the released layer from the DLC 11. Thus, the release layer 17a and the oxygen-impermeable layer 17b is removed after HT. A particularly good release liquid for use with the materials of the embodiment shown in Figure 5, is hot water. Exemplary thicknesses in this embodiment are the thickness of the barrier layer 6 of silicon nitride or silicon oxynitride formed by sputtering about 125 or 150 Å; DLC-layer thickness of approximately 11 to 50 Å; MgOh thickness of layer 17a of about 190 Å and a thickness of the SiC-layer 17b of about 280 Å.

6 shows an example embodiment where the release layer 17a is composed of or includes a suboxide of zinc (ZnOx), and the oxygen barrier or oxygen-impermeable layer 17b consists of or includes aluminum nitride (AlN). Additionally, in some cases, this embodiment can provide a barrier layer 6 between the DLC 11 and the glass substrate 1 to reduce sodium migration during or due to HT. After heat treatment or HT (e.g., annealing) the product is exposed to a mildly reactive liquid (e.g., water, vinegar, dilute ammonia and / or bleach), and the liquid penetrates through the release layer 17a on the microchannels or grain boundaries in the overlying layer (s ) and causes the discharge of the released layer from the DLC 11. Thus, the release layer 17a and the oxygen-impermeable layer 17b is removed after HT. A particularly good release liquid for use with the materials of the embodiment shown in Figure 6, is vinegar. Approximate thickness in this embodiment is as follows: the thickness of the barrier layer 6 of silicon nitride approximately 150 Å; DLC-layer thickness of approximately 11 to 50 Å; ZnOx-thickness layer 17a about 500 Å and the thickness of the AlN-layer 17b of about 200 Å.

7 shows an example embodiment where release layer 17a is composed of or includes a suboxide Mg (MgOx), and the oxygen barrier or oxygen-impermeable layer 17b consists of or includes aluminum nitride (AlN). Additionally, in some cases, this embodiment can provide a barrier layer 6 between the DLC 11 and the glass substrate 1 to reduce sodium migration during or due to HT. After heat treatment or HT (e.g., annealing) the product is exposed to a mildly reactive liquid (e.g., water, vinegar, dilute ammonia and / or bleach), and the liquid penetrates through the release layer 17a on the microchannels or grain boundaries in the overlying layer (s ) and causes the discharge of the released layer from the DLC 11. Thus, the release layer 17a and the oxygen-impermeable layer 17b is removed after HT. A particularly good release liquid for use with the materials of the embodiment shown in Figure 7, is hot water. Exemplary thicknesses in this embodiment, are thick DLC-layer 11 is about 50 Å; MgOh thickness of layer 17a of about 230 Å and a thickness of AlN-layer 17b of about 200 Å.

In certain embodiments of this invention coated articles due HT lose no more than about 15% of the visible light transmittance, more preferably not more than about 10%. Moreover, monolithic coated articles after HT preferably have visible light transmittance of at least about 50%, more preferably at least about 60 or 75%.

In any of the embodiments discussed above (see., E.g., Figures 1-7) may also provide an additional layer, a scratch-resistant (e.g., consisting of or containing SiC or DLC - not shown) over the layer 17b.

While the invention has been described based on the most practical and preferred embodiments, it should be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, it is intended that various modifications and equivalent alterations covered spirit and scope of the appended claims.