镍-磷-氮化硅复合化学镀工艺优化

Optimization for electroless plating of nickel-phosphate-silicon nitride composite coating

以Q235碳钢为基底进行Ni–P–Si3N4复合化学镀。以镀层的显微硬度为指标,通过正交试验得到的最优配方和工艺条件为:硫酸镍29 g/L,次磷酸钠30 g/L,氟化氢铵15 g/L,柠檬酸三钠10 g/L,硫脲0.003 g/L,氮化硅2 g/L,十二烷基硫酸钠0.04 g/L,pH 4.5,温度85℃,时间1.5 h。该条件下所得Ni–P–Si3N4复合镀层为非晶态结构,表面平整致密,厚度47.8μm,显微硬度313.4 HV,结合力良好。

Electroless plating of Ni–P–Si3N4 composite coating was conducted on Q235 steel substrate.The bath composition and process conditions were optimized using the microhardness of coating as evaluation index as follows:nickel sulfate 29.0 g/L,sodium hypophosphite 30.0 g/L,ammonium hydrogen fluoride 15.0 g/L,sodium citrate 10.0 g/L,thiourea 0.003 g/L,silicon nitride 2.0 g/L,sodium dodecyl sulfate 0.04 g/L,pH 4.5,and time 1.5 h.The Ni–P–Si3N4 composite coating obtained thereby was smooth,compact,and well-adhered with an amorphous structure,a thickness of 47.8μm,and a microhardness of 313.4 HV.