AZ31B镁合金表面镍基复合镀层的制备及耐蚀性能研究

Research on Preparation and Corrosion Resistance of Nickel-based Composite Plating on AZ31B Magnesium Alloy Surface

为了提高镁合金的耐腐蚀性,以AZ31B镁合金为基体,采用化学镀与脉冲电镀技术在其表面制备了Ni-P/Ni复合镀层。采用扫描电镜(SEM)、X射线衍射(XRD)分析了镀层表面的形貌和成分。通过电化学极化、阻抗测试和接触角研究了该复合镀层的耐腐蚀性和疏水性。结果表明:峰值电流密度为30 mA/cm^(2)时,镀层的晶粒最细致,接触角最高为117.3°,自腐蚀电位最高(-0.4510 V),腐蚀电流密度最低(1.94×10^(-7)A/cm^(2)),阻抗值最大,明显优于镁合金基体,这说明该复合镀层可提高镁合金疏水性和耐腐蚀性。

In order to improve the corrosion resistance of magnesium alloy,Ni-P/Ni composite coating was prepared on the surface of AZ31B magnesium alloy using chemical plating and pulse plating techniques.Scan electron microscope(SEM)and X-ray diffractometer(XRD)were employed to detect the surface morphology and composition of the composite coating.Besides,the corrosion resistance and hydrophobicity of the composite coating were investigated by electrochemical polarization,impedance tests and contact angle tests.The results show that with the peak current density of 30 mA/cm2,the coating has the most detailed grain,the highest contact angle of 117.3°,the highest self-corrosion potential(-0.4510 V),the lowest corrosion current density(1.94×10^(-7)A/cm^(2)),and the largest impedance value,which is obviously better than that of the magnesium alloy matrix,indicating that the composite coating could improve the hydrophobicity and corrosion resistance of magnesium alloy.