The Ni-P-SiC composite produced by electro-codeposition

In this work, SiC particles were incorporated into nickel phosphorus (Ni-P) alloy matrix by direct current plating and the effects of current density and SiC concentration on the compositions and the microhardness of the Ni-P-SiC deposits were investigated. The results reveal that increasing the current density or the SiC concentration in the bath increases the SiC content in the deposit. Adding SiC to the Ni-P alloy matrix substantially reduces the residual stress in the deposit and, therefore, eliminates surface cracking. SiC also greatly lowers the phosphorus content in the deposit and then increases the hardness to a maximum of 770 Hv when the mass fraction of phosphorus in the deposit is about 3.7%. At higher phosphorus content, the deposits are associated only with grains with the (1 1 1)Ni preferred orientation. When the phosphorus content is close to or under 3.7%, the structure becomes more random and includes (2 0 0)Ni and (2 2 0)Ni planes.