Patent ID: 9139915
Filing Date: 2015-09-22
Classification: C09K,C23C,C23G

Abstract:
1. A method for surface treatment of aluminum or aluminum alloy, comprising the steps of: immersing a workpiece comprising aluminum or aluminum alloy at least at one surface and having an aluminum oxide film on a surface of the aluminum or aluminum alloy in a dissolving solution; and forming a substituent metal layer of a metal, which is capable of substituting aluminum and contained in the solution on the aluminum or aluminum alloy surface, while removing the aluminum oxide film from the aluminum or the aluminum alloy surface, wherein the dissolving solution comprises: a salt or oxide of the metal capable for substituting aluminum; a solubilizing agent for ions of the metal; and an alkali, the dissolving solution having a pH of 10 to 13.5, wherein the metal is selected from the group consisting of manganese, cobalt, nickel, tin, lead, copper, mercury, silver, platinum, gold, and palladium; the concentration of the metal salt or metal oxide in the dissolving solution is not less than 1 mg/L but not more than 5,000 mg/L in terms of metal amount; the solubilizing agent is selected from the group consisting of aminocarboxylic acids and salts thereof, phosphorous acid chelating agents and salts thereof, and amine chelating agents; the total concentration of the solubilizing agent in the dissolving solution is 0.5 to 10 times (molar ratio) of the concentration of the metal salt or metal oxide.