KR20090099364A - A temperable low-emissivity glass with enhanced durability and a method for preparing the same - Google Patents

Abstract

A temperable low-emissivity glass showing excellent durability and a manufacturing method thereof are provided to show excellent handling and storage properties as well as durability and to secure visible light transmission rate of 70% or greater. A temperable low-emissivity glass comprises: a first dielectric layer coated on a glass substrate; a first functional reflection metal protective layer containing Ni-Cr alloy or a 50 and less mol% oxidized or nitrified Ni-Cr alloy; a functional reflection metal layer for reflecting infrared ray or the solar radiant light; a second functional reflection metal protective layer containing Ni-Cr alloy or a 50 and less mol% oxidized or nitrified Ni-Cr alloy; a second dielectric layer; and an uppermost protective layer. The first and second dielectric layers are independently made of Silicon nitride or oxide.

Description

Heat-resistant low-spinning glass with excellent durability and manufacturing method thereof {A TEMPERABLE LOW-EMISSIVITY GLASS WITH ENHANCED DURABILITY AND A METHOD FOR PREPARING THE SAME}

The present invention relates to a durable heat-resistant low-emissivity glass (commonly referred to as 'roy glass') and a method of manufacturing the same, and more particularly, to a first dielectric layer, sequentially coated on a glass substrate, 1 A functional reflective metal protective layer, a functional reflective metal layer that reflects infrared and / or solar radiation, a second functional reflective metal protective layer, a second dielectric layer, and a top protective layer, in contrast to conventionally known heat treatable low-emissive glass The present invention relates to a heat-resistant low-spinning glass and a method of manufacturing the same which improve durability.

It is well known that energy loss occurs most frequently through windows in buildings, and various methods have been tried to prevent this energy loss.

Among these attempts, there is a method of coating a window glass surface with a thin metal film multilayer that typically controls solar radiation. This method is largely divided into two types, one is pyrolysis and the other is magnetron sputter coating. In the former case, the coating film is very strong by deposition coating at a high temperature using a relatively stable oxide such as SnO ₂ : F material. However, the solar control performance is poor, and the coating material is limited, which is insufficient to satisfy the needs of various consumers. The latter magnetron sputtering coating method is a method for depositing various coating films such as functional metals, metal oxides and metal nitrides as a post-processing process on float glass, and apparatuses for this are already widely commercialized.

However, in such coating glass for construction, it is a recent trend to require visible light transmittance of 70% or more in addition to the basic function of preventing energy loss.

In addition, in certain cases, this kind of low-emission glass needs to be subjected to bending or prestressing treatments (often heat treatment) of the bending or tempering type. For this purpose, the glazing is typically heated to a temperature of about 600 to 700 ° C. prior to the actual treatment of bending or prestressing. During this thermal stress, the silver (Ag) layer, which is a functional reflective metal layer, is often oxidized and diffused. Due to the structural deformation caused by. Such deformation of the silver layer can be confirmed through the change of the transmittance, the sheet resistance of the coated surface, and the emissivity even if it is not visible to the naked eye.

Thus, low-emissivity glass that can withstand high thermal stress, very low emissivity before thermal (preliminary stress) treatment, maintains high optical properties, and does not compromise other quality standards of the coating such as hardness, color and chemical resistance Demand has increased in recent years, and various methods have been proposed for the purpose of improving this kind of multilayer coating film. Examples thereof include the following.

One known method proposed to prevent degradation of reflective metal films such as silver (Ag) at high temperatures is to sandwich (Ti / Ag / Ti) silver films between protective films of oxidizable metals such as titanium. The thickness of such a protective metal film is usually sufficient for the protective metal film to oxidize when the coated glass is heated at a high temperature. Since thick metal oxide films are generally transparent than thin metal films, the transmittance of glass sheets with such coatings tends to increase upon heating. Such techniques are described in US Pat. No. 4,790,922 and US Pat. No. 4,806,220.

The membrane structure proposed in patent EP-0718250 on the other hand introduces an oxygen barrier diffusion layer, in particular a layer based on silicon nitride (Si _x N _y ), on top of a functional layer or layers based on silver, and a priming layer. It is recommended to place the silver layer directly above the underlying dielectric coating without inserting a priming layer or protective metal layer. This suggests a multilayer structure of type Si ₃ N ₄ / ZnO / Ag / Nb / ZnO / Si ₃ N ₄ or SiO ₂ / ZnO / Ag / Nb / Si ₃ N ₄ . Multilayer structures of Si ₃ N ₄ / Nb / Ag / Nb / Si ₃ N ₄ are also described in this patent.

International Publication No. WO97 / 48649 discloses Si ₃ N ₄ / Nb / Ag / Nb / which can be toughened (reinforced heat treatment) with two thin metal "blocking" layers based on niobium and 0.7 to 2 nm thick. Multilayer structures of the same type as Si ₃ N ₄ have been described. In addition, US Pat. No. 6,804,048 describes a heat treatable low-emissive glass having a glass / SnO ₂ / ZnO / Ag / Nb / Si ₃ N ₄ layer structure. However, the problem is that Nb metals have limitations in use as rare metals.

US Pat. No. 5,821,001 uses ZnO added with Sn as the first and second dielectric layers, Ti or ZnO as the first protective layer, Ti as the second protective layer, and TiO ₂ as the top layer. A low-emissivity glass capable of heat treatment is described.

It is a technical object of the present invention to provide a highly durable low-emission glass having a high visible light transmittance of preferably 70% or more after heat treatment and capable of post-processing heat treatment (bending, strengthening).

The present invention to solve the above technical problem, the first dielectric layer sequentially coated on a glass substrate; A first functional reflective metal protective layer comprising a Ni—Cr alloy or a Ni—Cr alloy nitrided or oxidized to 50 mol% or less; A functional reflective metal layer that reflects infrared or solar radiation; A second functional reflective metal protective layer comprising a Ni—Cr alloy or a Ni—Cr alloy nitrided or oxidized to 50 mol% or less; A second dielectric layer; And a top protective layer; provides a heat treatable low-emission glass comprising a.

In addition, according to another aspect of the invention, a first dielectric layer on a glass substrate; A first functional reflective metal protective layer comprising a Ni—Cr alloy or a Ni—Cr alloy nitrided or oxidized to 50 mol% or less; A functional reflective metal layer that reflects infrared or solar radiation; A second functional reflective metal protective layer comprising a Ni—Cr alloy or a Ni—Cr alloy nitrided or oxidized to 50 mol% or less; A second dielectric layer; And a top protective layer; there is provided a method of manufacturing a heat-treatable low-emissive glass, which includes sequentially coating.

According to the present invention, the visible light transmittance is 70% or more, good handling properties and storage in the warehouse during processing, excellent durability, and can be easily produced low-emission glass capable of post-heat treatment.

The high durability, high transmittance heat treatable low-emission glass of the present invention includes a first dielectric layer sequentially coated on a glass substrate; A first functional reflective metal protective layer comprising a Ni—Cr alloy or a Ni—Cr alloy nitrided or oxidized to 50 mol% or less; A functional reflective metal layer that reflects infrared or solar radiation; A second functional reflective metal protective layer comprising a Ni—Cr alloy or a Ni—Cr alloy nitrided or oxidized to 50 mol% or less; A second dielectric layer; And a top protective layer; the characteristics of each layer will be described in detail below.

First, as the glass substrate, conventional glass such as soda-lime glass for building or automobile can be used without limitation. In addition, it is possible to freely use a glass having a thickness of 2mm ~ 6mm depending on the purpose of use.

The first and second dielectric layers serve to block heat transferred to the functional reflective metal layer during heat treatment such as reinforcement and bending. In the present invention, the material of the first and second dielectric layers is a nitride of Si or a nitride oxide such as Si _x N _y , Si _x N _y O _z (x = 1 to 3, y = 1 to 4, z = 1 4) etc. are preferable. The Si _x N _y or Si _x N _y O _z dielectric layer not only blocks heat transfer to the functional reflective metal layer during heat treatment, but also has three times the hardness of glass, giving excellent durability to low-emissive glass.

The thickness of the first and second dielectric layers is preferably in the range of 10 to 55 nm, more preferably the first dielectric layer has a thickness of 30 to 45 nm, and the second dielectric layer has a thickness of 30 to 55 nm. It is good. If the thickness of each of the first and second dielectric layers is less than 10 nm, there may be a problem that the durability of the coating film is lowered, and if it exceeds 55 nm, there may be a problem that the visible light transmittance is significantly lowered.

The first and second functional reflective metal protective layers act as barriers to prevent the movement of Na and O _{2 in} the air diffused in the glass during heat treatment such as strengthening and bending, and finally penetrate into the functional reflective metal layer. It plays an important role in absorbing O ₂ . In the present invention, the metal source for forming the first and second functional reflective metal protective layers is an alloy of Ni—Cr metal, an oxide or nitride thereof of 50 mol% or less, such as NiCrN _x , NiCrO _x (x = 0 to 2). In particular, the NiCr alloy preferably has a weight ratio of Ni: Cr of 95: 5 to 65:35, more preferably 90:10 to 70:30, and most preferably 80:20. When the Ni-Cr alloy is oxidized or nitrided, if its oxidation or nitriding ratio exceeds 50 mol% based on 100 mol% of the total amount of metal, K (absorption coefficient Extinction coefficient) increases due to excessive nitriding or oxidation during film formation. There is a problem that the absorption of the film is increased, and eventually the visible light transmittance is lowered. When the Ni—Cr alloy is oxidized or nitrided, the preferred oxidation or nitriding ratio is 0.1 to 50 mol%, more preferably 1 to 45 mol%, even more preferably 10 to 40 mol%. Further, the first and second functional reflective metal protective layers may be the same or may be different from each other.

The thickness of the first and second functional reflective metal protective layers is preferably in the range of 0.8 to 5 nm. If the thickness of any of the functional reflective metal protective layer is less than 0.8 nm, there may be a problem that the film is damaged during the heat treatment, and if it exceeds 5 nm, there may be a problem that the transmittance is too low.

The functional reflective metal layer serves to selectively transmit and reflect solar radiation. In the present invention, Ag, Au, Cu, or the like may be used as the material of the functional reflective metal layer, and Ag is most preferred.

The thickness of the functional reflective metal layer is preferably in the range of 5 to 10 nm, more preferably 6 to 9 nm. When the thickness of the functional reflective metal layer is less than 5 nm, the emissivity may be increased, thereby causing a problem in performance as a low-e glass, and when exceeding 10 nm, the visible light transmittance may be too low.

Lastly, the uppermost protective layer is for improving the durability of the heat-resistant low-radiation glass, and is preferably made of a material having excellent durability. Also, a film with a low absorption coefficient is advantageous for obtaining various optical properties.

Low radiation glass typically has a series of structures to prevent degradation of the least durable metal layers, such as silver (Ag) layers. However, even if there is no deterioration of the silver (Ag) layer, if scratches occur, the scratches are more noticeable when the refractive index of the layer in contact with the atmosphere is higher than when the refractive index is low. In addition, when the layer in contact with the atmosphere is crystallized, the surface becomes rougher than in the case of amorphous, so that scratches are easily generated. Therefore, the uppermost protective layer is preferably made of a material having good durability, small absorption coefficient, refractive index of 1.8 or less, and amorphous material. Such materials include TiO ₂ , SiO ₂ , Al ₂ O ₃ , and the like, and SiO ₂ is suitable. However, these materials have a problem that it is very difficult to form a film having a desired thickness by vacuum deposition by sputtering.

Therefore, in the present invention, at least one element selected from Al, In, Sn, Tl, Pb, Sb, Bi, Ti, Zr, Hf, V, Nb and Ta is preferably added as a material for the uppermost protective layer (alloy). Oxide of Si or Al is used. Such an oxide of Si or Al may be represented by the general formula of M-SiO ₂ or M-Al ₂ O ₃ . (M = Al, In, Sn, Tl, Pb, Sb, Bi, Ti, Zr, Hf, V, Nb, Ta)

The content of the element M added (alloyed) to the oxide of Si or Al is preferably 30 to 50% by weight of the total weight of the uppermost protective layer. If the content is less than 30% by weight, there is a disadvantage in that it is difficult to form a coating film. If the content exceeds 50% by weight, the absorption coefficient is increased to decrease the transmittance.

It is preferable that the thickness of the said uppermost protective layer is more than 0.8 nm-less than 10 nm. If the thickness is 0.8 nm or less, it is difficult to obtain the effect of improving the durability, and if it is 10 nm or more, there is a problem that the visible light transmittance of the low-emissive glass is lowered, which is not preferable.

When the low-emissivity glass is manufactured by applying the uppermost protective layer metal film as described above, scratch resistance and chemical resistance are improved compared to the existing low-emission glass, and the durability is excellent due to sweat or saliva, and the handleability is advantageous, and 70% or more. By having a high visible light transmittance, it is possible to obtain a low-emission glass suitable for use in construction.

In addition to the functional layers described above, the low-emissive glass of the present invention may further include functional layers that are generally employed in the low-emissive glass within the scope of achieving the object of the present invention.

The low-emission glass of the present invention as described above, the first dielectric layer on the glass substrate; A first functional reflective metal protective layer comprising a Ni—Cr alloy or a Ni—Cr alloy nitrided or oxidized to 50 mol% or less; A functional reflective metal layer that reflects infrared or solar radiation; A second functional reflective metal protective layer comprising a Ni—Cr alloy or a Ni—Cr alloy nitrided or oxidized to 50 mol% or less; A second dielectric layer; And a top protective layer; may be prepared by a method comprising the steps of sequentially coating.

According to one embodiment of the present invention, the low-emissive glass of the present invention may be prepared by coating using a magnetron-magnetic magnet (C-Mag) sputter coater as shown in FIG. 2. In the sputter coater of FIG. 2, t 1-12 are all silicon tubular targets used to coat a target for forming a dielectric layer, such as Si _x N _y , and P1 and P3 are targets for forming a functional reflective metal protective layer, such as NiCr target (Ni: Cr = 80: 20), and P2 is a target for forming a functional reflective metal layer, such as an Ag target. P4 is a planar type target for forming the uppermost protective layer. According to one embodiment of the invention, a glass substrate is introduced into the sputter coater of FIG. 2 and the respective functional layers are sequentially coated while moving from zones 1 to 4. The thickness of each layer can be easily adjusted by adjusting the moving speed of an organic substrate and / or the sputtering speed by voltage regulation of each target.

The low-emissivity glass of the present invention is preferably a D65 standard light source of 380-780 nm when the thickness of the transparent glass substrate is 6 mm, the visible light transmittance is 70% or more when measured before heat treatment and 74% or more measured after heat treatment.

Moreover, the low-emissivity glass of this invention, Preferably, sheet resistance is 13 GPa / sq or less, and emissivity is 0.15 or less.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the scope of protection of the present invention is not limited by these embodiments.

Example  One

Using a magnetron (C-Mag) sputter coater as shown in Figure 2, a low-emissive glass with a film having a composition and thickness as shown in Table 1 was prepared.

The first Si ₃ N ₄ layer was first coated on a 6 mm thick transparent glass at a thickness of 36 nm under an atmosphere of nitrogen / argon (nitrogen 80% argon 20%). The first NiCr layer was then coated with a thickness of 2 nm under 100% argon atmosphere, and the Ag metal layer was coated with a thickness of 8.5 nm under 100% argon atmosphere. The second NiCr layer, like the first NiCr layer, was coated with a thickness of 1 nm under an argon 100% atmosphere, after which the second Si ₃ N ₄ The layer was coated with a thickness of 47 nm under a nitrogen / argon (nitrogen 80% argon 20%) atmosphere. Finally, the upper protective layer was coated with a Ti-SiO ₂ layer (Ti: Si weight ratio = 50: 50) at a thickness of 2 nm in 100% O ₂ atmosphere to prepare the low-emissive glass of Example 1.

Example  2 ~ 4

The low-emissive glass was manufactured on the same conditions as Example 1 except having changed the metal target which forms a top protective layer into Al, Sb, and Sn, respectively. (M-SiO ₂ (M = Al, Sb, Sn, M: Si weight ratio = 50:50))

Example  5

Same conditions as in Example 1 except that the first functional reflective metal protective layer and the second functional reflective metal protective layer were changed to NiCrN (30 mol% nitriding rate) under a nitrogen / argon (nitrogen: argon = 30: 70) atmosphere. A low-emissive glass was prepared.

Example  6

Same conditions as in Example 1 except that the first functional reflective metal protective layer and the second functional reflective metal protective layer were changed to NiCrO ₂ (oxidation rate 30 mol%) under an oxygen / argon (oxygen: argon = 30: 70) atmosphere. A low-emissive glass was prepared.

Example  7

A low-emissive glass was manufactured under the same conditions as in Example 1 except that the Si ₃ N ₄ layer, which was the first dielectric layer and the second dielectric layer, was changed to SiO ₂ N.

Example  8

A low-emissive glass was manufactured under the same conditions as in Example 1 except that Ti-SiO ₂ forming the uppermost protective layer was changed to Ti-Al ₂ O ₃ . (Ti: Al weight ratio = 50:50)

Example  9

A low-emissive glass was manufactured under the same conditions as in Example 1 except that Ti-SiO ₂ forming the uppermost protective layer was changed to Ti-Zr-SiO ₂ . (Ti: Zr: Si weight ratio = 30:20:50)

Example  10

A low-emissive glass was manufactured under the same conditions as in Example 1 except that Ti-SiO ₂ forming the uppermost protective layer was changed to Ti-In-SiO ₂ . (Ti: In: Si weight ratio = 25:25:50)

Example  11

Same as Example 5 except that the first functional reflective metal protective layer and the second functional reflective metal protective layer were changed to NiCrN (40 mol%) in a nitrogen / argon (nitrogen: argon = 40: 60) atmosphere. Low-emissivity glass was manufactured on condition.

Example  12

Same as Example 6 except the first functional reflective metal protective layer and the second functional reflective metal protective layer were replaced with NiCrO ₂ (oxidation rate 20 mol%) under an oxygen / argon (oxygen: argon = 20: 80) atmosphere. Low-emissivity glass was manufactured on condition.

Example  13

SiO ₂ N as the first dielectric layer, NiCr as the first functional reflective metal protective layer, NiCrN (30 mol% nitride) as the second functional reflective metal protective layer, SiO ₂ N as the second dielectric layer, Ta- as the upper protective layer A low-emissive glass coated with a metal film was prepared from Bi-Al ₂ O ₃ (Ta: Bi: Al = 30: 20: 50 weight ratio).

Comparative example  One

Comparative Example 1 was prepared in the same membrane structure as Example 1 except for the uppermost protective layer.

Comparative example  2

The same conditions as in Example 5 except that the first functional reflective metal protective layer and the second functional reflective metal protective layer were changed to NiCrN (60 mol% nitriding rate) under a nitrogen / argon (nitrogen: argon = 60: 40) atmosphere. A low-emissive glass was prepared.

Comparative example  3

The same conditions as in Example 6 except that the first functional reflective metal protective layer and the second functional reflective metal protective layer were changed to NiCrO ₂ (oxidation rate 60 mol%) under an oxygen / argon (oxygen: argon = 60: 40) atmosphere. A low-emissive glass was prepared.

The glass samples of the prepared examples and comparative examples were heat-treated in the following manner:

In the general reinforcing furnace used in the production of tempered glass, the glass sample was passed through the glass sample while being heated at a temperature of about 600 to 700 ° C. for about 5 minutes, and then heat-treated under rapid cooling conditions.

Visible light transmittance was measured in accordance with KS L 2514 standard with D65 standard light source of 380 ~ 780 nm, respectively, before and after heat treatment. Emissivity was measured through a spectrometer FT-IR (KS L 2514 standard).

The sheet resistance is a value measured by Ag, which is a functional reflective metal layer, and indicates whether or not the sheet has a performance as a low-emissive glass even after heat treatment. A lower value indicates better performance. The emissivity is calculated with the reflectance value in the 5-50 μm infrared region by Ag, and the lower the emissivity, the better the performance.

The measurement results for the above items are shown in Table 3 below.

As can be seen from Table 3, the low-emissivity glass produced by the embodiment according to the present invention has excellent visible light transmittance before and after heat treatment, and is also excellent in sheet resistance and emissivity, which is suitable for use in building glass, etc. Example visible light transmittance is very low compared to the embodiment is limited to use for construction.

It can be seen that Comparative Examples 2 and 3, in which the oxidation or nitriding rates of the first and second functional reflective metal protective layers exceed 50 mol%, have a significantly lower visible light transmittance than Examples 5 and 6.

As can be seen from Table 3, in contrast to Examples 5 and 6 and Comparative Examples 2 and 3, the visible light transmittance of Comparative Examples 2 and 3 is about 6 to 7% lower than that of Examples, and thus, the first and second functional reflections. When the metal protective layer is oxidized or nitrided at more than 50 mol%, it can be seen that there is a problem that the visible light transmittance is lowered.

Next, the following experiments were conducted to perform the durability test.

First, the scratch resistance test was performed on the samples before the heat-treatment of Examples 1 to 13 and Comparative Examples 1 to 3 using a Heidon 18L scratch tester, and the results are shown in Table 7 below.

In the scratch resistance test, the prepared specimens were cut into a size of 200 * 100 mm to prepare a total of 8 sheets each, and a scratch was observed by visually pressing the coated surface with a load of 60 g using a 1 μm diameter Sapphire Tip. Proceed to the method of confirming the occurrence.

Next, the chemical resistance test was performed for the samples before heat treatment reinforcement of Examples 1 to 13 and Comparative Examples 1 to 3 by the following method.

1. Moisture resistance test

Examples 1-7, Comparative Example 1 The specimen was cut to size 100 * 100mm and treated for 2 hours in a constant temperature and humidity chamber maintained at 50 ° C. and 90%, and then the color change (ΔEnbs) of the coated surface was measured and treated for 2 weeks. Afterwards, the number of pinholes having a diameter of 1.5 mm or more was measured. The results are shown in Table 5.

2. Acid resistance test

Examples 1 to 13 and Comparative Examples 1 to 3 were cut to size 60 * 40 mm, immersed in 0.01 N HCl solution, and after 1 day, the transmittance, coating surface reflectance (Rf), and sheet resistance change amount were recorded. Shown in

3. Base resistance test

Examples 1 to 13 and Comparative Examples 1 to 8 were cut to size 60 * 40 mm, and the transmittance, coating surface reflectance (Rf), and sheet resistance change after 1 day of immersion in 0.1N NaOH solution were recorded, and the results are shown in Table 7. It was.

4. Salinity Resistance Test

Examples 1 to 13 and Comparative Examples 1 to 3 were cut to a size of 60 * 40 mm, and the transmittance, coating surface reflectance (Rf), and sheet resistance change after 1 day of immersion in a 0.25 wt% NaCl solution were recorded. Shown in

5. Handling test

During the glass working process, the worker's sweat or saliva may be inadvertently buried on the coated glass surface, causing defects in the coated glass, and the following tests were conducted to evaluate the effect.

Examples 1 to 13 and Comparative Examples 1 to 3 were prepared by cutting specimens of size 100 * 100 mm and uniformly applying the sweat and saliva of the experimenter to 1 cm in width and 1 cm in height, and after 1 week, washed and visually examined and microscopically observed. It was carried out to check the occurrence of defects and the results are shown below.

(Microscopic observation result)

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view schematically showing a layer structure of heat-treated low-emissive glass of the present invention.

2 is a view schematically showing an example of a coating apparatus configuration for producing a low-emissive glass according to the present invention.

Claims (8)

A first dielectric layer, sequentially coated on the glass substrate; A first functional reflective metal protective layer comprising a Ni—Cr alloy or a Ni—Cr alloy nitrided or oxidized to 50 mol% or less; A functional reflective metal layer that reflects infrared or solar radiation; A second functional reflective metal protective layer comprising a Ni—Cr alloy or a Ni—Cr alloy nitrided or oxidized to 50 mol% or less; A second dielectric layer; And an uppermost protective layer. The low radiation glass according to claim 1, wherein the materials of the first and second dielectric layers are each independently nitride or nitride of Si. The material of claim 1, wherein the material of the uppermost protective layer is Si or Al to which at least one element selected from Al, In, Sn, Tl, Pb, Sb, Bi, Ti, Zr, Hf, V, Nb and Ta is added. Low-emissivity glass characterized by being an oxide.        The low emission glass of claim 1, wherein the functional reflective metal layer is Ag. The method according to claim 1, wherein when the thickness of the transparent glass substrate is 6mm, the visible light transmittance is 70% or more when measured before heat treatment and 74% or more when measured after heat treatment with a D65 standard light source of 380-780 nm. Glass. The low radiation glass according to claim 1, wherein the sheet resistance is 13 GPa / sq or less and the emissivity is 0.15 or less. A first dielectric layer on the glass substrate; A first functional reflective metal protective layer comprising a Ni—Cr alloy or a Ni—Cr alloy nitrided or oxidized to 50 mol% or less; A functional reflective metal layer that reflects infrared or solar radiation; A second functional reflective metal protective layer comprising a Ni—Cr alloy or a Ni—Cr alloy nitrided or oxidized to 50 mol% or less; A second dielectric layer; And a top protective layer; sequentially coating the low-emissivity glass. 8. The method of claim 7, wherein the first and second dielectric layers are coated using a silicon tubular magnetron sputter coater.

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