Aluminum member for electrodes and method for producing aluminum member for electrodes

Abstract

Provided is an aluminum member for electrodes capable of stably maintaining a low electric resistance state, and a method of producing an aluminum member for electrodes. An aluminum member for electrodes includes an aluminum substrate and an oxide film that is laminated on at least one main surface of the aluminum substrate, and the oxide film has a density of 2.7 to 4.1 g/cm3 and a thickness of 5 nm or less.

What is claimed is: 
     
         1 . An aluminum member for electrodes comprising:
 an aluminum substrate;   an oxide film that is laminated on at least one main surface of the aluminum substrate; and   a plurality of through holes that penetrate the aluminum substrate and the oxide film in a thickness direction,   wherein the oxide film has a density of 2.7 to 4.1 g/cm 3  and a thickness of 5 nm or less.   
     
     
         2 . The aluminum member for electrodes according to  claim 1 ,
 wherein the oxide film contains any one of aluminum oxide (Al 2 O 3 ), aluminum oxide monohydrate (Al 2 O 3 .1H 2 O), or aluminum oxide trihydrate (Al 2 O 3 .3H 2 O).   
     
     
         3 . The aluminum member for electrodes according to  claim 1 ,
 wherein the oxide film contains 70% or more of aluminum oxide (Al 2 O 3 ).   
     
     
         4 . The aluminum member for electrodes according to  claim 1 ,
 wherein the oxide film contains 45% or less of aluminum oxide monohydrate (Al 2 O 3 .1H 2 O) and aluminum oxide trihydrate (Al 2 O 3 .3H 2 O).   
     
     
         5 . The aluminum member for electrodes according to  claim 1 ,
 wherein an average opening diameter of the through holes is 0.1 μm or more and less than 100 μm.   
     
     
         6 . The aluminum member for electrodes according to  claim 1 ,
 wherein an average opening ratio of the through holes is 0.5% to 30%.   
     
     
         7 . The aluminum member for electrodes according to  claim 1 ,
 wherein the aluminum substrate has a thickness of 5 μm to 100 μm.   
     
     
         8 . The aluminum member for electrodes according to  claim 1 ,
 wherein the oxide film is laminated on both surfaces of the aluminum substrate.   
     
     
         9 . A method of producing an aluminum member for electrodes for producing the aluminum member for electrodes according to  claim 1 , the method comprising:
 a coating forming step of carrying out an electrolytic treatment in a first acidic aqueous solution using an aluminum substrate as a cathode to form an aluminum hydroxide coating on a surface of the aluminum substrate;   a coating removing step of bringing the aluminum substrate after the coating forming step into contact with an alkaline aqueous solution to remove the aluminum hydroxide coating; and   an oxide film forming step of bringing the aluminum substrate after the coating removing step into contact with a second acidic aqueous solution to form an oxide film on the surface of the aluminum substrate.   
     
     
         10 . The method of producing an aluminum member for electrodes according to  claim 9 , further comprising:
 a through hole forming step of carrying out an electrolytic treatment in a third acidic aqueous solution using the aluminum substrate as an anode to form through holes in the aluminum substrate and the aluminum hydroxide coating after the coating forming step and before the coating removing step.   
     
     
         11 . The method of producing an aluminum member for electrodes according to  claim 9 ,
 wherein the second acidic aqueous solution includes nitric acid, sulfuric acid, phosphoric acid, oxalic acid, or a mixed acid of two or more thereof.   
     
     
         12 . The method of producing an aluminum member for electrodes according to  claim 9 ,
 wherein the second acidic aqueous solution includes nitric acid, sulfuric acid, or a mixed acid thereof.   
     
     
         13 . The method of producing an aluminum member for electrodes according to  claim 9 , further comprising:
 a water washing step of washing the aluminum substrate with water after the oxide film forming step.   
     
     
         14 . The method of producing an aluminum member for electrodes according to  claim 13 , further comprising:
 a drying step of removing a water film adhering to the oxide film of the aluminum substrate after the water washing step.   
     
     
         15 . The method of producing an aluminum member for electrodes according to  claim 14 ,
 wherein the drying step is a step of heating the aluminum substrate to 100° C. to 200° C.   
     
     
         16 . The method of producing an aluminum member for electrodes according to  claim 13 , further comprising:
 an oxide film densification step of heating the aluminum substrate after the water washing step and removing a hydrate contained in the oxide film of the aluminum substrate to densify the oxide film.   
     
     
         17 . The method of producing an aluminum member for electrodes according to  claim 16 ,
 wherein a heating temperature in the oxide film densification step is 100° C. to 400° C.