Investigation of preparative process of composite powder for electroless nickel plating on copper-matrix

Composite powder for electroless nickel plating on copper-matrix was prepared by means of hydrazine reduction.Six major parameters were selected for experimental investigation of powder preparation:initial concentration of nickelion,initial concentration of hydrazine,its pH value,plating temperature,heat-retaining period,and addition amount of copper powder,and an orthogonal array test L_(25)(5~6) was designed accordingly.A great number of experiment were performed to get optimal technological parameters as follows:initial concentration of nickel sulphite was 30 g/L,initial concentration of hydrazine-70 ml/L,pH value-12,plating temperature-82 ℃,addition amount of copper powder-15 g/L,and heat-retaining period-35 min.SEM (EDS included) and XRD were used to analyze and test the power for nickel plating onto copper with foregoing parameters.The investigation result showed that the surface of plating with such powder was rougher than that with original powder and the particles of the powder became remarkable bygger.There was no inclusion inside the coating layer and it was also shown by the test on the chemical and processing performances of the powder that the performance indices of the powder were excellent.