【摘要】 在含NaOH、Na2SiO3和Na2B4O7的电解液体系中对AZ31镁合金进行阳极氧化处理,考察了柠檬酸添加量对阳极氧化膜性能的影响。用扫描电子显微镜观察阳极氧化膜的形貌,用X射线衍射分析氧化膜的结构形态,用电化学交流阻抗谱和动电位极化曲线表征氧化膜对镁合金耐蚀性能的影响。结果表明,柠檬酸的添加有效地抑制了火花放电,得到微孔分布均匀、致密的氧化膜。柠檬酸含量为12 g/L时,所得到的氧化膜具有最大的电荷传递电阻和膜电阻,其腐蚀电位和腐蚀电流密度分别为-1.379 V(相对于饱和甘汞电极)和1.930×10-7 A/cm2,氧化膜对镁合金具有最好的保护作用。更多还原

【Abstract】 AZ31 magnesium alloy was anodized in an electrolyte containing Na OH, Na2SiO3 and Na2B4O7. The influences of citric acid amount on properties of anodized film on magnesium alloy were studied. The surface morphology of the anodized film was observed by scanning electron microscopy(SEM), and the microstructure of the anodized film was analyzed by X-ray diffraction(XRD). The effect of anodized film on corrosion resistance of magnesium alloy was characterized by electrochemical impedance spectroscopy(EIS) and Tafel polarization measurement. The results indicated that the spark discharge is effectively restrained by addition of citric acid, and a dense anodized film with uniformly distributed micro-poles can be obtained. The anodized film obtained with 12 g/L citric acid has the maximal charge transfer resistance and film resistance, as well as a corrosion potential of-1.379 V and a corrosion current density of 1.930 × 10-7 A/cm2, showing the best protection for AZ31 magnesium alloy substrate.更多还原