(中国科学院 金属研究所 材料环境腐蚀试验研究中心,
沈阳 110015)
摘 要: 对镁合金传统化学镀工艺进行了改进, 避免了使用氢氟酸和六价铬等有毒物质。 采用化学镀与化学复合镀相结合方法, 在AZ91D镁合金上获得了Ni-P-ZrO2纳米化学复合镀层,并研究了新工艺化学镀前处理和镍沉积机理及复合镀层的结构和性能。 结果表明: 新工艺方法获得的Ni-P镀层更均匀、致密, 耐蚀性优于传统工艺化学镀层; Ni-P-ZrO2复合镀层与AZ91D合金基体在3.5%NaCl 溶液中的动电位极化曲线对比表明, 该复合镀层对镁合金可以起到明显的保护作用;从磨损实验结果可见, Ni-P镀层的磨损质量损失率几乎为Ni-PZrO2镀层的3倍, 说明ZrO2纳米粉的加入能改善镀层的耐磨性。
关键字: A291D镁合金; Ni-P-ZrO2镀层;化学复合镀; 耐蚀性; 耐磨性
(Environmental Corrosion Center, Institute of Metals Research,
Chinese Academy of Sciences, Shenyang 110016, China)
Abstract: Traditional process of electroless Ni-P plating on AZ91D magnesium alloy was improved, and the poisonous substances of hydrofluoric acid and Cr6+ were not used. The mechanism of pretreatment and nickel initial deposition for new process was investigated. Meantime, the process of Ni-P-ZrO2 composite plating was developed, and the microstructure and properties of the composite coating were studied. The results show that the Ni-P coating prepared with new process is more compact and uniform, and the corrosion resistance is superior to that of traditional process Ni-P coating. The potentiodynamic polarization curves in 3.5%NaCl solution indicate that the Ni-P-ZrO2 composite coating could provide adequate protection to magnesium alloy substrate. The wear mass loss of Ni-P coating is nearly twice more than that of Ni-P-ZrO2 coating, implying that the wear resistance of the composite coating is improved due to the co-deposition of ZrO2 nanometer particles.
Key words: AZ91D magnesium alloy; Ni-P-ZrO2 coating; electroless composite plating; corrosion resistance; wear resistance