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利用含新型三元复合络合剂的酸性化学镀镍液体系,在AZ91D镁合金表面通过化学镀制备Ni-P防护镀层。结果表明,镀层沉积速率随着镀液中三元复合络合剂浓度的变化而改变。利用X射线衍射(XRD)、扫描电子显微镜(SEM)和差热分析(DSC)对镀层结构、形貌以及热稳定性进行表征和分析。通过交流阻抗(EIS)和动电位扫描极化曲线对Ni-P镀层在3.5%NaCl溶液中的耐蚀性能进行评价。镀液中三元复合络合剂的浓度对Ni-P镀层的结构与形貌有显著影响。Ni-P镀层的热稳定性随着三元复合络合剂浓度的增加而降低。当镀液中三元复合络合剂浓度为0.035 mol/L时,所制备的Ni-P镀层致密、均一,在3.5%NaCl溶液中表现出良好的耐蚀性能。
Ni-P protective coating was prepared by chemical plating on the surface of AZ91D magnesium alloy by using acidic electroless nickel plating liquid system containing novel ternary complex complexing agent. The results show that the deposition rate of the coating changes with the concentration of the ternary complex complexing agent in the bath. The structure, morphology and thermal stability of the coatings were characterized and analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analysis (DSC). The corrosion resistance of Ni-P coatings in 3.5% NaCl solution was evaluated by alternating current impedance (EIS) and potentiodynamic polarization curves. The concentration of ternary complex complexing agent in the plating bath has a significant effect on the structure and morphology of the Ni-P coating. The thermal stability of Ni-P coatings decreases with the concentration of ternary complex complexing agent. When the concentration of ternary complex complexing agent in the bath is 0.035 mol / L, the prepared Ni-P coating is dense and uniform, and shows good corrosion resistance in 3.5% NaCl solution.