Conversion coating for aluminum and its alloys and articles thereof

Abstract

I provide a non-toxic protein and protein compound conversion coated metal article, a painted or plated non-toxic protein and protein compound conversion coated metal article, the aqueous coating solution to provide the in-situ conversion protective coating, and a process of preparing the article. The article is a metal selected from the group consisting of aluminum and aluminum alloy. The solution has a pH of 3.0 to 12.0 and preferably 4.0 to 10.0 and a protein and protein compound concentration of 0.1 to 10% by weight and the protein and protein compound have a molecular mass of 16,700 to 1,000,000.

1 . A non-toxic aluminum or aluminum alloy aqueous coating composition wherein the essential ingredient is a non-toxic protein or a protein compound or a mixture thereof to provide an outer protective coating for the non-toxic aluminum or aluminum alloy. 
   
   
       2 . The composition of  claim 1  wherein the protein or protein compound has a molecular mass of from 16,700 to 1,000,000. 
   
   
       3 . The composition of  claim 1  wherein there is 0.1 to 10% by weight of the protein and protein compound. 
   
   
       4 . The composition of  claim 1  wherein the pH of the composition is from 3.0 to 12.0. 
   
   
       5 . The composition of  claim 4  wherein the pH of the composition is from 4.0 to 10.0. 
   
   
       6 . The composition of  claim 1  wherein the protein is selected from the group consisting of casein, dried egg white, gelatin, serum albumin, hemoglobin, lacto globulin, gliadin. and mixtures thereof. 
   
   
       7 . The composition of  claim 6  consisting of
 0.1 to 10% by weight of the protein and protein compound, water and compounds to adjust the pH to it desired range.   
   
   
       8 . The composition of  claim 1  wherein
 the protein or protein compound has a molecular mass of from 16,700 to 1,000,000 and provides a concentration of 0.1 to 10%,   the protein is selected from the group consisting of casein, dried egg white, gelatin, serum albumin, hemoglobin, lacto globulin, and gliadin. and mixtures thereof,   the pH of the composition is from 4.0 to 10.0, and   the composition provides an in-situ conversion coating on the aluminum or aluminum alloy that will provide oxidation resistance to the aluminum or aluminum alloy for at least 5 days at room temperature and allow the conversion coated metal to be painted such that a cured painted metal showed no signs of blistering and no signs of adhesion failure, and   the composition provides an in-situ conversion coating on the aluminum or aluminum alloy that allows the conversion coated aluminum or aluminum alloy to be electroless plated and then placed in an oven at 350° F. for one half hour, removed and immediately quenched in water and the plated metal showed no signs of blistering or loss of adhesion.   
   
   
       9 . A metal article wherein the metal is selected from the group consisting of aluminum and aluminum alloy and said metal having thereon an in-situ non-toxic protein or protein compound conversion coating. 
   
   
       10 . The article of  claim 9  wherein the conversion coated metal is painted or electroless metal plated. 
   
   
       11 . The article of  claim 9  wherein the protein is selected from the group consisting of casein, dried egg white, gelatin, serum albumin, hemoglobin, lacto globulin, gliadin. and mixtures thereof, and the composition provides an in-situ conversion coating on the metal that will provide oxidation resistance to the metal for at least 5 days at room temperature. 
   
   
       12 . The article of  claim 10  wherein the protein is selected from the group consisting of casein, dried egg white, gelatin, serum albumin, hemoglobin, lacto globulin, gliadin. and mixtures thereof, and
 A cured painted conversion coated metal showed no signs of blistering and no signs of adhesion failure, and   an electroless plated conversion coated metal when placed in an oven at 350° F. for one half hour, removed and immediately quenched in water showed no signs of blistering and no signs of adhesion failure   
   
   
       13 . The article of  claim 12  wherein the protein or protein compound has a molecular mass of 16,700 to 1,000,000. 
   
   
       14 . A process of preparing the article of  claim 9  comprising cleaning a metal selected from the group consisting of aluminum and aluminum alloy,
 making the metal a cathode or anode of an electrolytic cell containing an aqueous solution of selected from protein and protein compounds, and   forming an in-situ protein conversion coating on the metal.   
   
   
       15 . The process of  claim 14  wherein
 the protein or protein compound has a molecular mass of from 16,700 to 1,000,000 and   the aqueous solution has
 a protein and protein compound concentration of 0.1 to 10%, and 
 a pH of the composition is from 4.0 to 10.0. 
   
   
   
       16 . The process of  claim 15  wherein the protein is selected from the group consisting of casein, dried egg white, gelatin, serum albumin, hemoglobin, lacto globulin, gliadin. and mixtures thereof, and painting or electroless plating the conversion coated metal. 
   
   
       17 . The process of  claim 16  wherein the conversion coated metal is cured, then painted or electroless metal plated wherein the cured painted conversion coated showed no signs of blistering and no signs of adhesion failure, and
 the electroless plated conversion coated metal when placed in an oven at 350° F. for one half hour, removed and immediately quenched in water showed no signs of blistering and no signs of adhesion failure.