Coated article with improved barrier layer structure and method of making the same

Description of the invention

The present invention relates to a coated article having a coating deposited on a substrate, including a metal or metal nitride layer sandwiched between an IR reflecting layer (e.g., an Ag layer) and an oxide barrier layer (e.g., NiCrO x).

Background of the invention

Coated articles intended for the regulation of solar radiation are well known. For example, see US Patent No. 5,344,718, which discloses a layer stack composed of: glass / Si3N4 / NiCr / Ag / NiCr / Si3N4. In coatings such as this, NiCr barrier layers are typically used to protect Ag (silver) in low-E coatings.

Unfortunately, metallic NiCr has a high absorption which reduces the transmittance of the final coated article. Due to this high absorption problem, the desired products with high visible transmission have necessitated the use of very thin NiCr barrier layers. For example, the NiCr layers in the above-mentioned document 718 are "less than about 7A" thick in order to achieve the desired visible transmission. The thinner such layers are, the worse the layer functionality and protection they provide. Consequently, those skilled in the art are seeking to increase the transmission of the barrier layer by introducing oxygen and / or nitrogen into the NiCr barrier layers (e.g., see US Patent No. 6,014,872 in col. 4 lines 40-50).

However, when considering a layer stack of glass / Si3N4 / NiCrO4 / Ag / NiCrOx / Si3N4, while the protective NiCrOx barrier layers are more transparent than the protective NiCr barrier layers, they have some problems. For example, the use of protective NiCrOx barrier layers in contact with the Ag layer on its respective sides can sometimes lead to durability and / or heat treatability problems. It is considered that during the deposition (e.g. by sputtering) of coatings containing protective NiCrO x barrier layers, the Ag layer is exposed to the oxygen plasma (and thus the chemically active atomic oxygen present in such plasma) used in the NiCrO x deposition; this is especially true of the upper surface of the Ag layer when the overlying NiCrOx protective barrier is applied directly thereon. Exposure of Ag to an oxygen containing plasma is believed to lead to problems with Ag adhesion at times.

From the above point of view, it is clear to one skilled in the art that there is a need for an improved structure of the barrier layer (s) to protect the IR reflecting layer (e.g. Ag).

Brief Summary of the Invention

It is an object of the present invention to provide an improved structure of barrier layer (s) for protecting an IR reflective layer, such as Ag in a coated article, and a corresponding method of manufacturing it.

Another object of the present invention is to provide a structure of the layer (s) that enables the protection of the IR reflecting layer and that is both fairly transmissive to visible light and enables a durable final coated article to be obtained.

Another object of the present invention is to meet one or more of the above-mentioned purposes and / or needs.

The invention therefore provides a coated article comprising a coating deposited on a substrate, the coating comprising an oxide layer comprising a metal or metal alloy oxide, a metallic infrared (IR) reflecting layer, further comprising a metal or metal nitride contact layer interposed between and contacting each of the metallic infrared (IR) reflecting layers and the oxide layer; and wherein the metal or metal nitride contact layer comprises the same metal or metal alloy as the oxide layer and the oxide layer comprises NiCrO x.

In a preferred embodiment, the coated article is an article wherein the IR reflecting layer comprises Ag and the metal or metal nitride contact layer comprises at least one of NiCr and CrNx.

According to a further embodiment of an article according to the invention, the coated article is defined by a layered resistance (Rs) of no more than 20 ohms / unit area, and a visible transmission of at least 70%.

Brief description of the drawings

Figure 1 is a cross sectional view of a coated article according to one embodiment of this invention.

PL 203 151 B1

Figure 2 is a cross sectional view of a coated article according to another embodiment of this invention.

Figure 3 is a cross sectional view of a coated article according to yet another embodiment of this invention.

Detailed Description of Exemplary Embodiments of the Invention

Referring now in particular to the accompanying drawings, where like reference numerals indicate like parts in the several drawings.

The coated article of various embodiments of this invention may be used in the context of building windows (e.g., IG units), vehicle windows, or any other suitable application. Coated articles within the meaning of the present invention may or may not be heat treated (e.g., thermally tempered, heat bent, or the like) in various embodiments of this invention.

Figure 1 is a cross sectional view of a coated article according to one embodiment of this invention. The coated article includes substrate 1 (e.g. glass substrate transparent, green, brown or blue-green from about 1.0 to 10.0 mm thick, more preferably from about 1.8 to 4 mm thick), first dielectric layer 3, lower barrier layer 5, lower barrier contact layer 7 (which is in contact with the IR reflecting layer 9), the first metallic, conductive infrared (IR) reflecting layer 9, the higher barrier contact layer 11 (which is in contact with the IR reflecting layer 9), the higher barrier layer 13, and a higher dielectric layer 15. "Contact" layers 7 and 11 each contact the IR reflecting layer 9. An example of non-limiting materials for layers 3-15 is shown in figure 1. The above-mentioned layers 3-15 provide a solar regulating coating (e.g., low-E or low-emissivity coating) that can be provided on glass or plastic substrates 1 The above-mentioned stack of layers 3-15 shown in Fig. 1 may, in certain alternative embodiments of this invention, be repeated on substrate 1 one or more times (e.g., a different array of layers 3-15 may be placed on top of the stack shown in fig. 1 on the same substrate - this applies to any and all embodiments herein).

In certain embodiments of this invention, the first dielectric layer 3 may be of or include titanium dioxide (TiO_xwhere x is 1.7 to 2.7, most preferably 2.0 to 2.6) silicon nitride (SixNy, where x / y may be about 0.75 (i.e. Si3N4), or else x / y may be from about 0.76 to 1.5 in Si rich embodiments), silicon dioxide (SiO x where x is from 1.7 to 2.3, most preferably about 2.0), niobium oxide (e.g., Nb2O5), SiZrN , tin oxide, zinc oxide, silicon oxynitride, or any other suitable dielectric substance. First dielectric layer 3 may function as an anti-reflection and / or color shifting layer in certain embodiments of this invention.

Infrared (IR) reflecting layer 9 is preferably metallic and conductive, and may be made of or may include silver (Ag), gold (Au), or any other suitable IR reflecting material. However, metallic Ag is the material of choice for the IR reflecting layer 9 in certain embodiments of this invention. The IR reflecting layer (s) helps enable the coating to exhibit low-E characteristics.

The barrier layers 5 and 13 are preferably at least partially oxidized, and in some embodiments of the present invention are made of or include nickel (Ni) oxide, or a nickel alloy oxide such as nickel chromic oxide (NiCrO x), or any other (different) material. . In the embodiment of Fig. 1, layers 5 and 13 include NiCrO_xwhich can either be fully oxidized / oxidized or only partially oxidized. In particular, NiCrO layers_x 5 and 13 may be fully oxidized in certain embodiments of this invention (ie, fully stoichiometrically), or may be at least 75% oxidized in other embodiments of this invention. While NiCrOx is the preferred material for barrier layers 5 and 13, those skilled in the art will appreciate that other materials (e.g., Ni oxides, Ni alloy oxides, Cr oxides, Cr alloy oxides, NiCrO may be used instead._xN_y, NiCrN_x, NbO_x or any other suitable material) for one or more of these layers. It is noted that barrier layers 5 and 13 may or may not be continuous in various embodiments of this invention.

Still referring to the barrier layers 5 and 13, these layers may or may not be gradually oxidized in the various embodiments of this invention. In certain embodiments, barrier layers 5 and 13 are approximately uniformly oxidized along their respective thickness (ie, not gradually). However, in other embodiments, the bariero4 layer

The components 5 and 13 may be oxidized gradually so that they will be less oxidized at the interface with the immediately adjacent layer (s) 7, 11 than in the part of the barrier layer (s) further or more / farthest from the immediately adjacent layer (s). contact. This can improve the adhesion of the metal or metal nitride contact layers 7, 11 to the barrier layers 5, 13, respectively. Such gradation may also enable the coating, in one exemplary non-limiting embodiment, to achieve a combination of heat treatability with high visible transmission. For a more detailed discussion of how layers 5 and / or 13 can be oxidized gradually, see valid US Patent No. 6,576,349, the disclosure of which is incorporated herein by reference.

Contact layers 7 and 11 (which contact the IR reflecting layer 9) are preferably more metallic and / or less oxidized than their respective adjacent barrier layers 5 and 13. For example, in certain embodiments of this invention, contact layers 7 and 11 may be of or include Ni, Cr, NiCr, CrNx, or NiCrNx (it has been noted that the term NiCrNx as used in this patent application includes the situation that when the Ni in the layer is metallic and the nitriding is mainly Cr). In such embodiments, layers 7 and 11 are either unoxidized or only slightly oxidized to a significantly lesser degree than barrier layers 5 and 13. Thus, in certain preferred example embodiments of this invention, contact layers 7 and / or 11 are substantially free of oxygen (i.e., less than about 10% oxidized), or are even only oxidized from 0-5% in certain embodiments.

Surprisingly, it has been found that by providing protective metal or metal nitride contact layers 7 and 11 (e.g. NiCr, Ni, Cr, CrN)_x, Nb, or NiCrN_x) on a substrate between the IR reflecting layer 9 (e.g. Ag) and the respective layers 5 and 13 (e.g. NiCrO_x), durability can be improved compared to the situation where the NiCrO_x 5 and 13, all in direct contact with the Ag layer 9. The use of thin metal or metal nitride contact layers 7 and / or 11 in contact with barrier layers 5 and / or 13 allows the resulting coated article to have both high permeability to in the visible range (i.e., at least 70% in some embodiments), and is stable both before and / or after heat treatment. It is noted that the metal or metal nitride contact layers 7 and 11 are provided to be rather thin (to reduce the adverse effect of visible light absorption) in some embodiments such that the contact layers 7 and 11 may or may not be be continuous in various embodiments of the present invention.

When NiCr is used in layers 5, 7, 11, and / or 13 in certain embodiments of this invention (i.e., a NiCr target is used in sputtering any of these layers whether they are oxidized, nitrided or not), Ni and Cr can be provided in various amounts such as nichrome with 80-90 wt% Ni and 10-20% Cr. An exemplary sputtering target for these layers includes not only SS-316, which consists essentially of 10% Ni and 90% other components, mainly Fe and Cr, but also Inconel and Haynes 214 alloy, which consists essentially by weight of (nominal composition ) the following substances that may also be present in these layers: Ni: 75.45%; Fe: 4%; Cr: 16%; C: 0.04%; Al: 4.5%; and Y: 0.01%. In other embodiments, the NiCr target may consist of 50/50 Ni / Cr or any other suitable ratio.

Still referring to Fig. 1, while a variety of materials and / or thicknesses may meet one or more of the objects of the invention considered above, exemplary preferred thicknesses and materials for the respective layers on the glass substrate 1 in the embodiment of Fig. 1 are as follows: :

Table 1

Examples of substances / thicknesses; the embodiment of fig. 1

<td>Layer</td><td>Beneficial range μιτι (A)</td><td>Most preferred μm range (A)</td><td>Example μm (A)</td>

<td> 1</td><td> 2</td><td> 3</td><td> 4</td>

<td>SixNy (layer 3)</td><td> 0-6*10² (0-600 A)</td><td> 3*10'²-55*10'³ (300-550 A)</td><td> 41*10'³-52*10'³ (410-520 A)</td>

<td>NiCrOx (layer 5)</td><td> 5*10'⁴-1*10'² (5-100 A)</td><td> 10'³-5*10'³ (10-50 A)</td><td> 15*10'⁴-3*10'³ (15-30 A)</td>

<td>NiCr (layer 7)</td><td> 1*10'⁴-25*10'⁴ (1-25 A)</td><td> 10'⁴-10'³ (1-10 A)</td><td> 3*10'⁴-4*10'⁴ (3-4 A)</td>

PL 203 151 B1 cont. table 1

<td> 1</td><td> 2</td><td> 3</td><td> 4</td>

<td>Ag (layer 9)</td><td> 5*10-3.25*10-³ (50-250 A)</td><td> 8*10-3-16*10'³ (80-160 A)</td><td> 10-²-14*10'³ (100-140 A)</td>

<td>NiCr (layer 11)</td><td> 1*10-⁴-25*10-⁴ (1-25 A)</td><td> 10'⁴-10'³ (1-10 A)</td><td> 3*10-⁴-4*10-⁴ (3-4 A)</td>

<td>NiCrOx (layer 13)</td><td> 5*10'⁴-1*10'² (5-100 A)</td><td> 10'³-5*10'³ (10-50 A)</td><td> 15*10'⁴-25*10'⁴ (15-25 A)</td>

<td>SixNy (layer 15)</td><td> 0-8*10^-2 (0-800 A)</td><td> 3*10-²-6*10·² (300-600 A)</td><td> 41*10'³-54*10'³ (410-540 A)</td>

Other layer (s) may also be provided below or above the illustrated coating.

Thus, while the layer system or coating in Fig. 1 is "on" or "deposited on" substrate 1 (directly or indirectly), other layer (s) may be interposed therebetween. Thus, for example, the coating in Fig. 1 may be considered "on" and "deposited on" the substrate 1, even though another layer (s) is located between the layer 3 and the substrate 1. Moreover, certain coating layers may be removed in certain embodiments, while others may be added in other embodiments of this invention without departing from the overall spirit of certain embodiments of this invention.

Figure 2 is a cross sectional appearance of a coated article according to another embodiment of this invention. The Fig. 2 embodiment is the same as the Fig. 1 embodiment, except that the lower contact layer 7 for the Fig. 1 embodiment is not present in the Fig. 2 embodiment. In particular, a metal or metal nitride contact layer 11 is provided only on the upper side of the Ag layer 9, since this is where the Ag layer is most sensitive to the problems of exposure to oxygen plasma as discussed above. In still further, but less preferred, embodiments of the present invention, a metal or metal nitride contact layer may be provided on the bottom of the Ag layer 9 but not on the top of layer 9 (i.e., inversely to Fig. 2). In the embodiment of Fig. 2, one skilled in the art will appreciate that layer 5 need not be NiCrO_xbut may instead be made of any other material including, but not limited to, titanium oxide (e.g., TiO₂), ZnAlO_xor the like.

Figure 3 shows the cross-sectional appearance of yet another embodiment of this invention where metal or metal nitride contact layer (s) 7 and / or 11 may be used. One skilled in the art will appreciate that these layers can be used in a variety of different coating stacks, and the dielectric substances of the coating (s) and the amounts of the IR reflecting layer (s) of the coating are not always of particular importance with respect to the contact layers described in this patent application. While the metal or metal nitride contact layer is positioned as follows: contact layer 11 over the lower Ag layer 9, and contact layer 11 'over the upper Ag θ' layer, in other embodiments of the present invention the metal or nitride contact layer or layers are metal may equally well be located beneath either or both of these layers or Ag layers, (e.g. see contact layer 7 in Fig. 1). For the embodiment of Fig. 3, exemplary materials and thicknesses (which, of course, are not limiting) are shown below in table 2.

Table 2

Examples of substances / thicknesses; the embodiment of fig. 3

<td>Layer</td><td>Beneficial range μιτι (A)</td><td>Most preferred μm range (A)</td><td>Example μm (A)</td>

<td> 1</td><td> 2</td><td> 3</td><td> 4</td>

<td>TiO2 (layer 2)</td><td> 0-4*10^-2 (0-400 A)</td><td> 5*10-3-25*10-³ (50-250 A)</td><td> 1*10-²-16*10'³ (100-160 A)</td>

<td>SixNy (layer 3)</td><td> 0-5*10^-2 (0-500 A)</td><td> 5*10-³-4*10-² (50-400 A)</td><td> 17*10'³-36*10'³ (170-360 A}</td>

<td>NiCrO_x (layer 5)</td><td> 5*10-⁴-1*10-² (5-100 A)</td><td>1 * 10-3-5 * 10-3 (10-50 A)</td><td> 15*10'⁴-3*10'³ (15-30 A)</td>

<td>Ag (layer 9)</td><td>5 * 10-3-25 * 10-3 (50-250 A)</td><td> 8*10-3-12*10'³ (80-120 A)</td><td> 105*10^-4 (105 A)</td>

<td>NiCr (layer 11)</td><td> 1*10-⁴-25*10-³ (1-25 A)</td><td> 1*10-⁴-10-³ (1-10 A)</td><td> 3*10-⁴*10-⁴ (3-4 A)</td>

<td>NiCrOx (layer 13)</td><td> 5*10'⁴-10'² (5-100 A)</td><td> 10'³-5*10'³ (10-50 A)</td><td> 15*10'⁴-3*10'³ (15-30 A)</td>

<td>SnO2 (layer 16)</td><td> 0-8*10^-2 (0-800 A)</td><td> 5*10'²-85*10'³ (500-850 A)</td><td> 65*10^-3 (650 A)</td>

PL 203 151 B1 cont. table 2

<td> 1</td><td> 2</td><td> 3</td><td> 4</td>

<td>SixNy (layer 18)</td><td> 0-8*10^-2 (0-800 A)</td><td> 5*10'³-25*10'³ (50-250 A)</td><td> 17*10^-3 (170 A)</td>

<td>NiCrOx (5 'layer)</td><td> 5*10'⁴-1*10'² (5-100 A)</td><td> 1*10'³-5*10'³ (10-50 A)</td><td> 15*10'⁴-3*10'³ (15-30 A)</td>

<td>Ag (9 'layer)</td><td> 5*10'⁴-25*10'³ (50-250 A)</td><td> 8*10'³-12*10'³ (80-120 A)</td><td> 105*10^-4 (105 A)</td>

<td>NiCr (11 'layer)</td><td> 1*10'⁴-25*10'⁴ (1-25 A)</td><td> 10'⁴-10'³ (1-10 A)</td><td> 3*10'⁴-4*10'⁴ (3-4 A)</td>

<td>NiCrO_x (layer 13 ')</td><td> 5*10'⁴-1*10'² (5-100 A)</td><td> 10'³-5*10'³ (10-50 A)</td><td> 15*10'⁴-3*10'³ (15-30 A)</td>

<td>SnO2 (layer 20)</td><td> 0-5*10^-2 (0-500 A)</td><td> 10'²-3*10'² (100-300 A)</td><td> 15*10^-3 (150 A)</td>

<td>Si₃N4 (layer 22)</td><td> 0-5*10^-2 (0-500 A)</td><td> 10'²-3*10'² (100-300 A)</td><td> 25*10^-3 (250 A)</td>

The embodiment of Fig. 1 of the present invention was made and tested as shown below. During the spray coating process in which the layers have been deposited

3-15: linear speed for the lower silicon nitride layer 3 (when used for sputtering a Si target) was 139.7 cm / min (55 in / min) using 8 runs, linear speed for the upper silicon nitride layer 15 (when applied to the sputtering of the Si target was 127 cm / min (50 inches / minute) using 8 runs; the line speed for the NiCr contact layers 7 and 11 was 100 in / minute volts 254 cm / min using one pass; and rope speed for NiCrO barrier layers_x 5 and 13 was 95.25 cm / min (37.5 inches / minute) using 2 runs.

Coating Machine Setting for the Fig. 1 Embodiment

<td>Disc material</td><td>Power (kW)</td><td>Volta (V)</td><td>Ar (cm³)</td><td>O2 (cm³)</td><td>N2 (cm³)</td><td>Thickness μιτι (A)</td>

<td>Si (layer 3)</td><td>1 kW</td><td>485 V</td><td> 40</td><td> 0</td><td> 40</td><td> 47*10^-3 (470 A)</td>

<td>NiCr (layer 5)</td><td>1 kW</td><td>415 V</td><td> 40</td><td> 10</td><td> 0</td><td> 22*10^-4 (22 A)</td>

<td>NiCr (layer 7)</td><td>0.38 kW</td><td>370 V</td><td> 30</td><td> 0</td><td> 0</td><td> 3*10^-4 (3 A)</td>

<td>Ag (layer 9)</td><td>2.95 kW</td><td>465 V</td><td> 30</td><td> 0</td><td> 0</td><td>R_s= 16 ohms /.</td>

<td>NiCr (layer 11)</td><td>0.38 kW</td><td>370 V</td><td> 30</td><td> 0</td><td> 0</td><td> 3*10^-4 (3 A)</td>

<td>NiCr (layer 13)</td><td>1 kW</td><td>415 V</td><td> 40</td><td> 10</td><td> 0</td><td> 22*10^-4 (22 A)</td>

<td>Si (layer 15)</td><td>1 kW</td><td>485 V</td><td> 40</td><td> 0</td><td> 40</td><td> 51*10^-3 (510 amps)</td>

As will be appreciated by one skilled in the art, the above-mentioned setting of the coater produces a layer stack on the glass substrate 1 composed of (from the substrate to the outside): Si₃N₄/ NiCrO_x/ NiCr / Ag / NiCr / NiCrO_x/ Si₃N₄. Of course, in other embodiments of this invention, the contact layer (s) 7 and / or 11 may be nitrided (fully or only partially) by adding nitrogen gas in the spray coating process of these layers 7 and / or 11. The optical characteristics of this particular example have been determined. as follows (III. C, 2-step observation technique was used to determine the transmission characteristics):

Optical characteristics of the example transmission (TY)%: 81.25% a * T: -2.24 b * T: 0.81 reflectance observed from the glass side (G): RGY (%): 7.54

L * G: 33.01 a * G: 0.56 b * G: -7.13 reflectance seen from the film / coating side (F): RFY (%): 5.07 a * F: 3.21 b * F: -5.30

R_s (surface resistance in (ohms /.): 16.00

PL 203 151 B1

This example has better durability than the comparative example where the metal contact layers are omitted.

Coated articles according to certain embodiments of this invention have a visible transmission of at least 65%, more preferably at least 70%, and most preferably at least 75%, and even sometimes at least 80%. Further, coated articles according to certain example embodiments of this invention have a sheet resistance (Rs) of no more than 20 ohms / c, more preferably no more than 16 ohms / c, and sometimes no more than 12 ohms / c. .

While the invention has been described in conjunction with what is herein contemplated as the most practical and preferred embodiment, it should be understood that the invention is not limited to the disclosed embodiment, but is intended to cover the various variations and equivalent settings conceived in and intended to be covered. scope of the attached reservations.