| 摘要 |
PURPOSE:To form an insulating film having excellent insulating property and heat resistance on an Al alloy, by anodizing the Al alloy having an anodic oxide film with a soln. contg. a fatty acid salt as the electrolyte for the anodization. CONSTITUTION:The Al alloy 1 is anodized in an acidic soln. of oxalic acid, etc., to form an anodic oxide film consisting of an extremely thin barrier layer 2 and a porous layer 3 having fine pores on the surface of the Al alloy 1. The A4l alloy 1 having the anodic oxide film is anodized with an aq. soln. contg. a fatty acid salt as the anolyte. An aq. soln. of at least one kind among the NH4 salt, Na, salt, and K salt of a fatty acid having 6-18 carbons in one molecule is appropriately used as the soln. contg. a fatty acid salt. The treating temp. is preferably controlled to <= about 70 deg.C. The barrier layer 2 of the anodic oxide film is made thicker and denser by such treatment, the pores in the porous layer 3 are filled with a fatty acid formed by the electrolysis of the fatty acid salt or its Al salt 4, and the infiltration of the plating soln. into the pore is prevented.
|
