AZ91Dマグネシウム合金における過マンガン酸浴から作製した化成皮膜の構造と耐食性 An investigation of the structure and corrosion resistance of a permanganate conversion coatings on AZ91D magnesium alloy
Conversion coatings for magnesium have traditionally been based on immersion treatment in the solution containing hexavalent chromium compounds. The excellent performance of these coatings as paint bases has been established in a broad range of application. However, the replacable surface treatment has been strongly emphasized by present environmental needs to eliminate hexavalent chromium. The development of a chemical conversion coatings in permanganate bath on magnesium alloys have been studied using mass gain measurements, measurements of corrosion potential, X-ray diffraction, X-ray photoelectron spectroscopy, glow discharge spectroscopy and microscopic examination. Chemical conversion coatings obtained from HF addition in bath consisted of the film that was composed mainly of manganese oxides and magnesium fluoride. It was found that these films formed amorphous composite coating. Corrosion resistances of permanganate chemical conversion coatings were comparable with that for chromating.
軽金属 50(3), 109-115, 2000-03-30
The Japan Institute of Light Metals