Method of processing metallic material for a conductive member cell and a method of adjusting surface roughness of the metallic material

Abstract

A method of processing a metallic material includes immersing ferritic stainless steel or austenitic stainless steel in an acid solution containing hydrochloric acid in an amount of two times or more relative to the concentration of nitric acid or an acid solution containing hydrofluoric acid in an amount of one and a half times or more relative to the concentration of nitric acid to adjust surface roughness of the metallic material.

1 . A method of processing a metallic material comprising: immersing ferritic stainless steel or austenitic stainless steel in an acid solution containing hydrochloric acid in an amount of two times or more relative to the concentration of nitric acid or an acid solution containing hydrofluoric acid in an amount of one and a half times or more relative to the concentration of nitric acid to adjust surface roughness of the metallic material. 
     
     
         2 . The method according to  claim 1 , wherein temperature of the acid solution is 45° C. or above. 
     
     
         3 . The method according to  claim 1 , wherein a passive film of a surface of the material and base metal at the surface are locally dissolved and, after dissolution, a passive film is regenerated, thereby forming fine irregularities of submicron order on the metallic material. 
     
     
         4 . The method according to  claim 1 , wherein the material has 0.3 μm or less of mean spacing of local peaks between adjacent minimal points of the surface roughness profile. 
     
     
         5 . A method of adjusting surface roughness of a metallic material comprising: immersing titanium or titanium alloy in an acid solution containing hydrochloric acid in an amount of three times or more relative to the concentration of nitric acid an acid solution containing hydrofluoric acid by three times or more of concentration to the concentration of nitric acid to adjust the surface roughness. 
     
     
         6 . The method according to  claim 3 , wherein temperature of the acid solution is 60° C. or below. 
     
     
         7 . The method according to  claim 5 , wherein a passive film of a surface of the material and base metal at the surface are locally dissolved and, after dissolution, a passive film is regenerated, thereby forming fine irregularities of submicron order on the metallic material. 
     
     
         8 . The method according to  claim 5 , wherein the material has 0.3 μm or less of mean spacing of local peaks between adjacent minimal points of the surface roughness profile.