pH对AZ31镁合金表面磷酸钙转化膜性能的影响  

Effect of pH on properties of calcium phosphate conversion film on AZ31 magnesium alloy

作　　者：左宏健 贾素秋[1] ZUO Hongjian;JIA Suqiu(Changchun University of Technology,Changchun 130000,China)

机构地区：[1]长春工业大学,吉林长春130000

出　　处：《电镀与涂饰》2021年第7期566-571,共6页Electroplating & Finishing

摘　　要：采用液相沉积法,以由硝酸钙和磷酸氢二铵组成的转化液在AZ31镁合金表面制备了一层转化膜,考察了转化液pH对膜层性能的影响。使用扫描电镜、能谱仪和X射线衍射仪分析了转化膜的形貌、组成和结构。通过人体仿生液浸泡和动电位极化曲线、电化学阻抗谱测试了转化膜的耐蚀性。结果表明,当转化液pH为5.5时,所制转化膜的主要成分为CaHPO_(4)·H_(2)O,能有效地保护基体。探讨了转化膜的成膜机理。A conversion film was prepared on the surface of AZ31 magnesium alloy by liquid-phase deposition with calcium nitrate and ammonium dihydrogen phosphate as raw materials.The effect of pH on properties of the conversion film was studied.The morphology,microstructure,and phase constitution of the conversion film were characterized by scanning electron microscopy,energy-dispersive spectroscopy,and X-ray diffractometry.The corrosion resistance of the conversion film was tested by immersing in simulated body fluid as well as by potentiodynamic polarization measurement and electrochemical impedance spectroscopy.The results showed that the conversion film prepared in the conversion solution with a pH of 5.5 was mainly composed of CaHPO_(4)·H_(2)O and protected the substrate effectively.The formation mechanism of the conversion film was discussed.

关 键 词：镁合金 磷酸盐转化膜 模拟体液 耐蚀性 成膜机理 

分 类 号：TG174[金属学及工艺—金属表面处理]