Method of surface-treating aluminum material for dissipating heat

Abstract

The present application relates to a method of surface-treating an aluminum material for dissipating heat, which is capable of increasing the radiation heat flux to thus enhance heat dissipation performance, and includes anodizing an aluminum material using an electrolyte composed of oxalic acid, and forming cobalt sulfide (CoS) in surface pores of the aluminum material thus sealing the surface of the aluminum material.

What is claimed is: 
     
         1 . A method of surface-treating an aluminum material for dissipating heat, the method comprising steps of:
 anodizing an aluminum material with an electrolyte comprising oxalic acid; and   sealing a surface of the aluminum material by formation of cobalt sulfide (CoS) in surface pores of the aluminum material.   
     
     
         2 . The method of  claim 1 , wherein the oxalic acid of the electrolyte upon anodizing has a concentration of 0.2˜0.8 M. 
     
     
         3 . The method of  claim 1 , wherein the electrolyte upon anodizing has a temperature of 10˜40° C. 
     
     
         4 . The method of  claim 1 , wherein anodizing is performed for at least 30 min. 
     
     
         5 . The method of  claim 1 , wherein the sealing step comprises:
 primarily immersing the anodized aluminum material in a cobalt acetate solution; and   secondarily immersing the aluminum material in an ammonium sulfide solution.   
     
     
         6 . The method of  claim 5 , wherein upon the primary immersion, cobalt acetate (Co(CH 3 COO) 2 ) of the cobalt acetate solution has a concentration of 100˜250 g/L. 
     
     
         7 . The method of  claim 5 , wherein upon the secondary immersion, ammonium sulfide ((NH 4 ) 2 S) of the ammonium sulfide solution has a concentration of 10˜50 g/L. 
     
     
         8 . A method of surface-treating an aluminum material for dissipating heat, the method comprising steps of:
 anodizing an aluminum material with an electrolyte comprising oxalic acid and a second acid selected from sulfuric acid, phosphoric acid or chromic acid, wherein a concentration of the second acid is between 0.1 to 1 M; and   sealing a surface of the aluminum material by formation of cobalt sulfide (CoS) in surface pores of the aluminum material.   
     
     
         9 . The method of  claim 8 , wherein the oxalic acid of the electrolyte upon anodizing has a concentration of 0.2˜0.8 M. 
     
     
         10 . The method of  claim 8 , wherein the electrolyte upon anodizing has a temperature of 10˜40° C. 
     
     
         11 . The method of  claim 8 , wherein anodizing is performed for at least 30 min. 
     
     
         12 . The method of  claim 8 , wherein the sealing step comprises:
 primarily immersing the anodized aluminum material in a cobalt acetate solution; and   secondarily immersing the aluminum material in an ammonium sulfide solution.   
     
     
         13 . The method of  claim 12 , wherein upon the primary immersion, cobalt acetate (Co(CH 3 COO) 2 ) of the cobalt acetate solution has a concentration of 100˜250 g/L. 
     
     
         14 . The method of  claim 12 , wherein upon the secondary immersion, ammonium sulfide ((NH 4 ) 2 S) of the ammonium sulfide solution has a concentration of 10˜50 g/L.