Double silver low-emissivity and solar control coatings

Abstract

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.

What is claimed is:  
     
         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.    
     
     
         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 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 including a zinc oxide;    a second sublayer including Ag; and    a third sublayer including an oxidized metal.    
     
     
         7 . The coating according to  claim 6 , wherein the zinc oxide comprises nitrogen.  
     
     
         8 . The coating according to  claim 6 , wherein the oxidized metal comprises an at least partially oxidized Ni—Cr alloy.  
     
     
         9 . 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.  
     
     
         10 . 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.  
     
     
         11 . 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.  
     
     
         12 . The coating according to  claim 11 , wherein the oxidized metal is an at least partially oxidized Ni—Cr alloy.  
     
     
         13 . 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 layer including a means for strengthening the at least one layer against thermally induced changes.  
     
     
         14 . A method of making a low-emissivity coating on a substrate, the method comprising 
 depositing at least one layer including Ag; and    forming the coating of  claim 1 .    
     
     
         15 . The method according to  claim 14 , wherein the depositing comprises sputtering.  
     
     
         16 . 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 a substrate; and    forming the coating of  claim 1 .    
     
     
         17 . 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 550nm;    a fourth layer including a second means for reflecting infrared radiation; and    a fifth layer including a means for protecting the coating from abrasion.    
     
     
         18 . The coating according to  claim 17 , 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 means for preferentially orienting a crystal structure of the second sublayer; and    the third sublayer includes an oxidized metal.    
     
     
         19 . The coating according to  claim 18 , wherein the oxidized metal comprises an at least partially oxidized Ni—Cr alloy.  
     
     
         20 . The coating according to  claim 17 , 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.    
     
     
         21 . The coating according to  claim 19 , wherein the zinc oxide comprises nitrogen.  
     
     
         22 . 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 including a first oxidized metal;    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 eight layer including a second oxidized metal; and    a ninth layer including silicon nitride.