机构地区: 中国科学院海洋研究所
出 处: 《中国腐蚀与防护学报》 2005年第5期267-270,共4页
摘 要: 采用扫描电镜、电化学阻抗方法,研究了镁合金AZ91D微弧氧化过程中不同电压下获得氧化膜的性能.结果表明,随着氧化电压的升高,可以获得三种不同性能的氧化膜:钝化膜、微火花氧化膜和弧光氧化膜.钝化膜很薄,厚度不足1μm,膜层的阻抗随着氧化电压升高略有增加,仍属于钝化膜性质;微火花放电后期得到的膜层较厚,厚度可达30μm,表面均匀、结构致密,具有最高的阻抗,可以达到8×107Ω;弧光放电阶段氧化膜最厚,但结构疏松、易碎,阻抗逐渐降低至1×107Ω.结果还指出,硅酸盐体系中微火花放电阶段后期形成的膜层具有最佳的性能;而且膜层的阻抗主要由氧化膜的有效厚度决定,与总厚度关系不大. With scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) technique, properties of oxide coatings produced at different voltage on AZ91D Mg alloy substrates by micro- arc oxidation technique have been investigated. Three types of oxide coatings, passive film, micro - spark oxide coating and spark oxide coating were formed corresponding to different range of voltages. The results showed that micro - spark oxide coating exhibited the best performance of compact, homogeneous and with high resistance, comparing with other two types of oxide coatings, due to its high effective thickness.