摘要
以硫酸镍为主盐、次磷酸钠为还原剂、柠檬酸钠为主络合剂,在钨合金表面进行化学镀镍。通过正交实验发现,pH对沉积速率的影响非常显著。并结合实际生产确定了最佳工艺条件为:30g/L的硫酸镍,25g/L的次磷酸钠,20g/L的柠檬酸钠,温度85℃,pH4.0。讨论了施镀时间对沉积速率与镀件外观的影响,以及稳定剂硫脲与加速剂氟化钠对沉积速率和镀液稳定性的影响。通过X射线衍射图证实该镀层为Ni-P合金。采用SEM及EDS分别对镀前、镀后及热处理3种样品的微观形貌及镀层成分进行了分析与比较,结果发现,经700℃热处理后的镀件表面不存在晶界和明显的缺陷,最为均匀、致密。浸泡实验表明镀后热处理样品耐蚀性最好,镀后样品次之。该镀液稳定,制得的镀层结合力良好。
Electroless Ni plating was carried out on the surface of tungsten alloy by using nickel sulfate as main salt, sodium hypophosphite as reducer and sodium citrate as main complexing agent. The results of orthogonal test reveal obvious effect of pH value on deposition rate, and the optimal process conditions were obtained in combination with practical production as follows： 30 g/L of nickel sulfate, 25 g/L of sodium hypophosphite, 20 g/L of sodium citrate, tempe rature of 85 ℃ and pH value of 4.0. The influences of plating time on deposition rate and the appearance of plated parts, as well as the influences of stabilizer thiourea and accelerator sodium fluoride on deposition rate and bath stability were discussed. The deposit was proved to be composed of Ni-P alloy through X-ray diffraction patterns. The deposit＇ s micro-morphology and compositions of pre-plated, plated and heat treated samples were analyzed and compared by using SEM and EDS. It is demonstrated that the surface of the plated part after heat treatment at 700 ℃ has no grain boundary and evident defects , and bas tbe most uniform and densest structure. The immension test shows that the plated sample after heat treatment has the greatest corrosion resistance, followed by the plated sample. The process has advantages of stable bath and deposit with good adhesion.
出处
《电镀与涂饰》
CAS
CSCD
2006年第3期8-12,共5页
Electroplating & Finishing
关键词
钨合金
化学镀镍
稳定剂
加速剂
正交试验
热处理
耐蚀性
tungsten alloy, electroless Ni plating
stabilizer
accelerator
orthogonal test
heat treatment
corrosion resistance
