The optimized plating bath formula and
plating parameters for the electroless Ni–Mo–P alloy deposits with different structures
were determined in this paper. The effect of
plating parameters, such as complex agents, pH value, MoO42- concentration and additives, on the composition and
structure of the Ni–Mo–P alloy deposits was investigated. The experimental results showed that among the complex agents used, only one made from sodium citrate tribasic dihydrate (C6H5Na3O7·2H2O) and sodium acetate trihydrate (CH3COONa·3H2O) was found to be helpful to the co-deposition of Ni and Mo to get good Ni-Mo-P alloy deposits. In the Ni–Mo–P alloy deposits there was a close relation between the Mo and P contents, and the structure changed from amorphous to crystalline with the increase of the Mo content in the deposits. Within a certain range of pH value (pH 6.5~10), the plating rate increased with the pH value going up. The effect of MoO42- concentration and pH value on the plating rate was found to present a waved form, having a maximum value. With the increase of plating rate, the corrosion resistance of the alloy deposits became better.