BLACK CHEMICAL CONVERSION TREATMENT SOLUTION FOR MAGNESIUM ALLOY, TREATING METHOD USING THE SAME, AND MAGNESIUM-ALLOY MEMBER USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a black chemical conversion treatment solution and a black chemical conversion treating method by which the surface of the casings and parts made of magnesium alloy can be economically treated while taking an environmental pollution problem, an environmental problem, etc., into consideration and maintaining the bare corrosion resistance, adhesion of coating and corrosion resistance of coating which are comparable with those of the chemical conversion coatings obtained by the conventional chromium-type chemical conversion treating method or non-chromium-type chemical conversion treating method using manganese containing solution and also a uniform black chemical conversion coating which cannot be obtained by the conventional chromium-type chemical conversion treating method or non-chromium-type chemical conversion treating method can be formed on the surface of the casings and parts made of magnesium alloy and also to provide black chemical conversion treated articles. SOLUTION: Phosphoric acid and a strontium compound are incorporated into the black chemical conversion treatment solution.