Double silver low-emissivity and solar control coatings
View Patent ↗A low-emissivity multilayer coating includes, in order outward from the substrate, a first layer including a layer containing titanium oxide, a layer containing silicon nitride, or a sublayer layer containing titanium oxide in combination with a sublayer containing silicon nitride; a second layer including Ag; a third layer including at least one layer selected from titanium oxide layers and silicon nitride layers; a fourth layer including Ag; and a fifth layer including silicon nitride. The color of the coatings can be varied over a wide range by controlling the thicknesses of the layers of titanium oxide, silicon nitride and Ag. A diffusion barrier of oxidized metal protects relatively thin, high electrical conductivity, pinhole free Ag films grown preferentially on zinc oxide substrates. Oxygen and/or nitrogen in the Ag films improves the thermal and mechanical stability of the Ag. Dividing the first layer of titanium oxide, the Ag layers, and/or the third layer with a sublayer of oxidized metal can provide greater thermal and mechanical stability to the respective layers.
1. A low-emissivity coating on a substrate, the coating comprising, in numerical order outward from the substrate,
a first layer including at least one layer selected from titanium oxide layers and silicon nitride layers;
a second layer including Ag;
a third layer including at least one layer selected from titanium oxide layers and silicon nitride layers;
a fourth layer including Ag; and
a fifth layer including silicon nitride, wherein
at least one of the second layer and the fourth layer comprises
a sublayer including Ag, and
a sublayer consisting of a fully oxidized Ni—Cr alloy directly on, and outward from the substrate from, the Ag of the sublayer including Ag.
2. The coating according to claim 1 , wherein the first layer is from 5 to 30 nm thick.
3. The coating according to claim 1 , wherein
the first layer includes a titanium oxide layer; and
the titanium oxide in the first layer is amorphous.
4. The coating according to claim 1 , wherein the third layer comprises at least one of a TiO 2 layer and a Si 3 N 4 layer.
5. The coating according to claim 1 , wherein the third layer comprises a superlattice of titanium oxide and silicon nitride.
6. The coating according to claim 1 , wherein at least one of the second layer and the fourth layer consists of, in numerical order outward from the substrate,
a first sublayer, which includes a zinc oxide;
a second sublayer, which includes Ag; and
a third sublayer, which includes a fully oxidized Ni—Cr alloy.
7. The coating according to claim 6 , wherein the zinc oxide comprises nitrogen.
8. The coating according to claim 1 , wherein the Ag in at least one of the second layer and the fourth layer further comprises at least one of oxygen and nitrogen.
9. The coating according to claim 1 , wherein the Ag in at least one of the second layer and the fourth layer further comprises a means for strengthening the Ag against thermally induced changes.
10. The coating according to claim 1 , wherein at least one of the first layer, the second layer, the third layer, and the fourth layer is divided by a layer of an oxidized metal.
11. The coating according to claim 10 , wherein the oxidized metal is an at least partially oxidized Ni—Cr alloy.
12. The coating according to claim 1 , wherein at least one layer of the first layer, the second layer, the third layer, and the fourth layer is divided by a layer including a means for strengthening the at least one layer against thermally induced changes.
13. The coating according to claim 1 , wherein the silicon nitride comprises less than a stoichiometric amount of nitrogen.
14. The coating according to claim 1 , wherein
the first layer includes a layer of SiN x , where 0<x≦1.34;
the third layer includes a layer of SiN x , where 0<x≦1.34; and
the fifth layer includes a layer of SiN x , where 0<x≦1.34.
15. The coating according to claim 14 , wherein the first layer includes a layer of SiN x , where x=1.34.
16. A method of making a low-emissivity coating on a substrate, the method comprising
depositing at least one layer including Ag on the substrate; and
producing the coating of claim 1 .
17. The method according to claim 16 , wherein the depositing comprises sputtering.
18. A method of making a low-emissivity coating on a substrate, the method comprising
a step for depositing at least one layer including Ag on the substrate; and
producing the coating of claim 1 .
19. A low-emissivity coating on a substrate, the coating comprising, in numerical order outward from the substrate,
a first layer including at least one layer selected from titanium oxide layers and silicon nitride layers;
a second layer including a first means for reflecting infrared radiation;
a third layer having an index of refraction greater than or equal to 1.9 at a wavelength of 550 nm;
a fourth layer including a second means for reflecting infrared radiation; and
a fifth layer including a means for protecting the coating from abrasion, wherein
at least one of the first means for reflecting infrared radiation and the second means for reflecting infrared radiation comprises
a sublayer including Ag, and
a sublayer consisting of a fully oxidized Ni—Cr alloy directly on, and outward from the substrate from, the Ag of the sublayer including Ag.
20. The coating according to claim 19 , wherein
at least one of the first means for reflecting infrared radiation and the second means for reflecting infrared radiation consists of, in numerical order outward from the substrate, a first sublayer, a second sublayer, which includes Ag, and a third sublayer, which includes a fully oxidized Ni—Cr alloy; and
the first sublayer includes a means for preferentially orienting a crystal structure of the second sublayer.
21. The coating according to claim 19 , wherein
at least one of the first means for reflecting infrared radiation and the second means for reflecting infrared radiation consists of, in numerical order outward from the substrate, a first sublayer, a second sublayer including Ag, and a third sublayer;
the first sublayer includes a zinc oxide; and
the third sublayer includes a means for preventing the Ag in the second sublayer from corroding.
22. The coating according to claim 21 , wherein the zinc oxide comprises nitrogen.
23. A low-emissivity coating on a transparent substrate, the coating comprising, in numerical order outward from the substrate,
a first layer including at least one layer selected from titanium oxide layers and silicon nitride layers;
a second layer including a zinc oxide;
a third layer including Ag;
a fourth layer consisting of a first fully oxidized Ni—Cr alloy directly on the Ag of the third layer;
a fifth layer including at least one layer selected from titanium oxide layers and silicon nitride layers;
a sixth layer including a zinc oxide;
a seventh layer including Ag;
an eighth layer consisting of a second fully oxidized Ni—Cr alloy directly on the Ag of the seventh layer; and
a ninth layer including silicon nitride.
24. The coating according to claim 22 , wherein
the first layer includes a layer of SiN x , where 0<x≦1.34;
the fifth layer includes a layer of SiN x , where 0<x≦1.34; and
the ninth layer includes a layer of SiN x , where 0<x≦1.34.
25. The coating according to claim 24 , wherein the first layer includes a layer of SiN x , where x=1.34.