研究論文
りん酸ナトリウム電解液中での火花放電を伴うAZ31Bマグネシウム合金のアノード酸化
2010 年 60 巻 11 号 p. 608-614
詳細
2010 年 60 巻 11 号 p. 608-614
The microstructures and corrosion resistance of the anodic oxide films formed on AZ31B magnesium alloy by anodizing under continuous sparking in alkaline phosphate electrolyte (Na3PO4) were investigated. Basically, voltage-current characteristic of AZ31B in Na3PO4 solution was the same to that obtained in other sodium salt electrolytes such as Na2SiO3 and NaAlO2. However, the anodic films formed in Na3PO4 solution exhibited the higher corrosion resistance than that of the films formed in other electrolytes because of the incorporation of substantial amount of magnesium phosphate. The microstructures (e.g., diameter and number of pores) of the anodic films formed under sparking accompanied by current or voltage oscillation and gas evolution were strongly affected by the degree of sparking such as size, number, and appearance frequency, not by the formation voltage itself. X-Ray diffraction analysis revealed the incorporation of crystalline Mg3(PO4)2 into the anodic film formed under the sparking condition of dielectric breakdown.
