研究了5种铝合金表面预活化处理工艺对随后化学镀镍层的光亮性及结合力的影响.确定了一种适用于LY12铝合金的碱性活化液配方,可代替浸锌处理.通过正交试验获得了化学镀镍的最佳配方及工艺条件为:硫酸镍25g/L,次磷酸钠22 g/L,柠檬酸钠30 g/L,UDIQ561稳定剂2 mg/L,UDIQ563复合添加剂0.2 mL/L,UDIQ562加速剂1.2 g/L,pH 4.8,温度90°C.该工艺沉积速率达3.50 gm/(cm<'2>.h),镀层显微硬度130～160 kgf/mm<'2>,镀层中磷含量可达15%(质量分数).获得的化学镀镍层致密、牢固、均匀性良好.该工艺简单,对环境影响不大.%Five processes for pre-activation of the surface of aluminum alloys were studied as related to the brightness and adhesion strength of electroless Ni coating prepared subsequently. An alkaline bath formulation suitable for activation of LY12 aluminum alloy was determined as an alternative to zinc immersion treatment. The optimal bath composition and process conditions were obtained by orthogonal test as follows: nickel sulfate 25 g/L, sodium hypophosphite 22 g/L, sodium citrate 30 g/L, UDIQ561 stabilizing agent 2 mg/L, UDlQ563 composite additive 0.2 mg/L, UDlQ562 accelerating agent 1.2 g/L, temperature 90 ℃ and pH 4.8. The process features deposition rate of 3.50 mg/(cm2.h), coating microhardness of 130-160 kgf/mm2 and phosphorus content of 15wt％. The electroless nickel coatings produced by the process are compact, well-adhered and uniform. The process has advantages of simpleness and environmental friendliness.
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