SURFACE TREATMENT OF ALUMINUM-CONTAINING MAGNESIUM ALLOY DIE CASTING

摘要

PROBLEM TO BE SOLVED: To provide a surface treatment method for Al-contg. Mg alloy die castings capable of yielding die cast products having excellent corrosion resistant. ;SOLUTION: The surfaces of the Al-contg. Mg die castings are subjected to a pyrophosphate treatment and are then subjected to a caustic alkali treatment. Metal oxide films having the corrosion resistant are formed on the treated surfaces by a sol-gel method or the surfaces of the Al-contg. Mg die castings are subjected the pyrophosphate treatment, then to the caustic alkali treatment and further to an anodic oxidation treatment and the metal oxide films having the excellent corrosion resistant are formed on the treated surfaces by the sol-gel method. The metal oxide films are preferably films consisting of the oxide of Ti, Zr, Hf, Ta, Al or Si.;COPYRIGHT: (C)1998,JPO