碘化钾对铝合金表面化学镀镍的影响

研究了碘化钾(KI)对LC4铝合金表面化学镀Ni-P合金层沉积速度的影响,采用金相显微镜、显微硬度计和交流阻抗等方法考察了碘化钾对Ni-P镀层形貌、显微硬度以及耐蚀性的影响.结果表明:KI使Ni-P合金镀层的沉积速度有所降低,使镀层表面缺陷数量减少,镀层致密性提高.随着镀液中KI含量的增加.镀层显微硬度逐渐降低,但都高于镀液中无KI时所得镀层的硬度.此外,KI也改善了镀层在w(NaCl)=3.5%溶液中的耐蚀性.镀液中KI的适宜含量为10～20 mg/L.

Effect of KI on Electroless Ni-P Coating for Aluminum Alloy

The effect of KI on the deposition velocity of Ni-P eleetroless plating coating for LC4 aluminium alloy was investigated, and the surface micrograph was observed using OM, and the surface micro-hardness and corrosion resistance of Ni-P coating were tested by micro-vicker and electrochemical impedance spectroscopy (EIS), respectively. The results show that KI decreases the deposition velocity and defects of Ni-P films, and the Ni-P surface morphology gets more homogenous, which contributes to higher micro-hardness and better corrosion resistance in 3.5wt% NaCl solution. The reasonable concentration of Kl in the bath is 10～20 mg/L.