铝材表面化学镀镍技术

在常规铝材化学镀镍工艺基础上，提出一种在酸性化学镀镍前增加一道碱性化学预镀镍工艺的铝材表面化学镀镍新技术。介绍了其预镀镍的工艺流程与操作要点。研制了一种中等浓度的含镍、铁的多元合金浸锌液，并通过正交实验得出了浸锌最佳方案，确定了碱性化学预镀镍的最佳配方：25g／L硫酸镍，25g/L次磷酸钠，30g／L柠檬酸三钠，10g／L焦磷酸钠，10-15mL／L三乙醇胺，30g/L氯化铵。弯曲试验表明，镀镍层与铝基体结合强度很高；镀镍层SEM照片显示，镀镍层晶粒尺寸大小均匀，各晶粒间结合紧密，孔隙率低，耐腐蚀能力强。

Electroless nickel plating technique on aluminum surface

Based on the normal electroless nickel plating technics on aluminum,a new technique was presented,which used the pre-plating technics with alkaline electroless nickel before acid electroless nickel plating. The process flow and operation hints of nickel pre-plating technics were introduced.A kind of zinc-immersion solution with middle nickel and iron ions content was prepared,the optimal zinc-immersion scheme was obtained with orthogonal experiments,and the optimal formula of pre-plating with alkaline electroless nickel was obtained as follows: 25g/L nickel sulfate,25 g/L sodium hypophosphite,30 g/L sodium citrate,10 g/L sodium pyrophosphate,10~15 mL/L triethanolamine,30 g/L ammonium chloride.The bending test proves that the nickel deposit has good adhesion to aluminum substrate.The SEM photo shows that the nickel deposit has even crystal size,good adhesion,low porosity and strong corrosion resistance.