主盐及还原剂对AZ31镁合金化学镀镍-磷合金的影响

以硫酸镍为主盐,次亚磷酸钠为还原剂的镀液体系在AZ31镁合金基体表面化学沉积镍-磷镀层,并通过扫描电子显微镜(SEM)、能谱分析(EDS)、金相分析和极化曲线等分析手段探讨了化学镀液中主盐和还原剂的摩尔浓度比(CNi2+/CH2PO-2)对镁合金表面Ni-P镀层的形貌、成分、沉积速度和耐蚀性能的影响。结果表明:CNi2+/CH2PO-2对Ni-P镀层形貌的影响较小,但与膜层中的镍、磷元素的含量呈明显的线性关系;当CNi2+/CH2PO-2在0.4~0.6之间时,镀层沉积速度最快;CNi2+/CH2PO-2为0.3和0.4时,所得镀层的耐蚀性能较好。综上,在仅考虑主盐和还原剂对镀层性能影响的前提下,CNi2+/CH2PO-2=0.4时所得镀层的综合性能最好。

Influence of Main Salt and Reducing Agent to Nickel-phosphorus Alloy on AZ31 Magnesium Alloy

Electroless plating nickelphosphorus alloy coating was conducted on the magnesium alloy, using plating solution system with nickel sulfate as the main salt and sodium phosphate as the reducing agent. The influences of the main salt and reducing agent molar concentration ratio on the morphology, composition, deposition rate and corrosion resistance of nickelphosphorus coatings were discussed by SEM, EDS, metallographic analysis and polarization curves. The results show that the coatings retain the same morphology at different molar concentration ratios. However, the phosphorus content linearly decreases with increasing main salt and reducing agent molar concentration. The deposition rate is the fastest while the main salt and reducing agent molar concentration ratio is in the range of 0.40.6. The coating has good corrosion resistance while the molar concentration is 0.3 or 0.4. From the above, the coatings, electrolessplated with the main salt and reducing agent molar concentration ratio of 0.4, have the best comprehensive performance, in only considering the effects of main salt and reducing agent on coating performance