Process for Making Heat Stable Color Anodized Aluminum and Articles Formed Thereby

Abstract

A process of hard anodizing or Type III anodizing an aluminum article creates a heat stable, hard anodized, color surface on the exterior of the article. The process includes anodizing the aluminum article to achieve a hard anodized base layer on a surface of the article. A copper layer is deposited after the exterior is hard anodized. A tin layer is deposited after the step of depositing the copper layer.

That which is claimed is: 
     
         1 . A cookware article formed by a hard anodizing process that creates a heat stable color surface, the process comprising:
 anodizing the cookware article to achieve a hard anodized base layer on a surface of the cookware article;   depositing a copper layer after anodizing the cookware article; and   depositing a tin layer after depositing a copper layer.   
     
     
         2 . The cookware article formed by the hard anodizing process of  claim 1 , wherein anodizing the cookware article is carried out in a liquid bath at a temperature of between about 46° F. and about 62° F. 
     
     
         3 . The cookware article formed by the hard anodizing process of  claim 1 , wherein anodizing the cookware article is carried out in a liquid bath for a duration of between about 8 minutes and about 30 minutes. 
     
     
         4 . The cookware article formed by the hard anodizing process of  claim 1 , wherein depositing the copper layer is carried out in a liquid bath for a duration of between about 1.00 minutes and about 5.00 minutes. 
     
     
         5 . The cookware article formed by the hard anodizing process of  claim 1 , wherein depositing the tin layer is carried out in a liquid bath for a duration of between about 0.25 minutes and about 4.00 minutes. 
     
     
         6 . The cookware article formed by the hard anodizing process of  claim 1 , wherein anodizing the cookware article is carried out in a liquid bath at a temperature of between about 46° F. and about 62° F. for a duration of between about 8 minutes and about 30 minutes. 
     
     
         7 . The cookware article formed by the hard anodizing process of  claim 1 , wherein anodizing the cookware article includes anodizing an aluminum cookware article. 
     
     
         8 . The cookware article formed by the hard anodizing process of  claim 1 , wherein the cookware article is an aluminum cookware article. 
     
     
         9 . A cookware article formed by a hard anodizing process to create a heat stable color surface on an exterior of the cookware article, the process comprising:
 anodizing the cookware article in a liquid bath at a temperature of between about 46° F. and about 62° F. for between about 8 minutes and about 30 minutes to achieve a hard anodized base layer on the exterior;   depositing a copper layer after anodizing using an electrolytic process in a copper sulfate solution; and   depositing a tin layer using an electrolytic process, after depositing a copper layer, in a tin sulfate solution.   
     
     
         10 . The cookware article formed by the hard anodizing process of  claim 9 , wherein depositing the copper layer includes providing the copper sulfate solution at about 70° F. and wherein the duration of depositing a copper layer is about 2.75 minutes. 
     
     
         11 . The cookware article formed by the hard anodizing process of  claim 9 , wherein depositing the tin layer includes providing the tin sulfate solution at about 70° F. and wherein the duration of depositing the tin layer is about 1.25 minutes. 
     
     
         12 . The cookware article formed by the hard anodizing process of  claim 9 , wherein depositing the copper layer is conducted with the copper sulfate solution at a temperature of between about 64° F. and about 76° F. for a duration of between about 1.00 minutes and about 5.00 minutes. 
     
     
         13 . The cookware article formed by the hard anodizing process of  claim 9 , wherein depositing the tin layer is conducted with the tin sulfate solution at a temperature of between about 64° F. and about 76° F. for a duration of between about 0.25 minutes and about 4.00 minutes. 
     
     
         14 . The cookware article formed by the hard anodizing process of  claim 9 , wherein the cookware article is an aluminum cookware article. 
     
     
         15 . A method of hard anodizing a cookware article to create a heat stable color surface on an exterior of the cookware article, the method comprising:
 anodizing the cookware article in a liquid bath at a temperature of between about 46° F. and about 62° F. for between about 8 minutes and about 30 minutes to achieve a hard anodized base layer on the exterior;   depositing a copper layer after anodizing using an electrolytic process in a copper sulfate solution; and   depositing a tin layer using an electrolytic process, after depositing a copper layer, in a tin sulfate solution.   
     
     
         16 . The method of  claim 15 , wherein depositing the copper layer includes providing the copper sulfate solution at about 70° F. and wherein the duration of depositing a copper layer is about 2.75 minutes. 
     
     
         17 . The method of  claim 15 , wherein depositing the tin layer includes providing the tin sulfate solution at about 70° F. and wherein the duration of depositing the tin layer is about 1.25 minutes. 
     
     
         18 . The method of  claim 15 , wherein depositing a copper layer is conducted with the copper sulfate solution at a temperature of between about 64° F. and about 76° F. for a duration of between about 1.00 minutes and about 5.00 minutes. 
     
     
         19 . The method of  claim 15 , wherein depositing a tin layer is conducted with the tin sulfate solution at a temperature of between about 64° F. and about 76° F. for a duration of between about 0.25 minutes and about 4.00 minutes. 
     
     
         20 . The method of  claim 15 , wherein the cookware article is an aluminum cookware article.