植酸转换膜对AZ31镁合金电化学腐蚀性能的影响

Impacts of the phytic acid conversion film on electrochemical corrosion of AZ31 magnesium alloy

镁合金的耐腐蚀性能不理想,从而严重阻碍了镁合金大规模的商业应用。在商用AZ31镁合金表面制备了植酸转换膜,采用扫描电镜、能谱仪、电化学工作站等进行了合金电化学腐蚀性能的检测。结果表明,表面制备的植酸转换膜显著改善了商用AZ31镁合金的电化学腐蚀性能;与未经表面处理的商用AZ31镁合金相比,制备了植酸转换膜的AZ31镁合金在20℃电解液中的开路电位和腐蚀电位分别正移185 m V、238 m V;在质量分数为5%的KOH电解液中的开路电位和腐蚀电位分别正移221 m V、218 m V。

Unsatisfactory corrosion resistance of magnesium alloys has seriously hindered large-scale commercial applications of the magnesium alloy. The phytic acid conversion film was prepared on the commercial AZ31 magnesium alloy surface, and electrochemical corrosion properties were analyzed by the scanning electron microscopy, the energy dispersive spectroscopy and the electrochemical workstation. The results show that phytic acid conversion film prepared on the surface can significantly improve electrochemical corrosion properties of commercial AZ31 magnesium alloy. Compared with that without the phytie acid conversion film, the open circuit potential and corrosion potential of AZ31 magnesium alloy with the phytic acid conversion film shift by 185 mV and 238 mV to the positive direction in 20℃electrolyte,and they shift by 221mV and 218mV to the positive direction in 5% （mass fraction） KOH electrolyte.