Influence of SiC and TiC nanoparticles reinforcement on the microstructure, tribological, and scratch resistance behavior of electroless Ni-P coatings.

Two different ceramic carbide nanoparticles (SiC, and TiC) were separately incorporated into the Ni-P matrix via the electroless deposition method. As prepared Ni-P, Ni-P-SiC, and Ni-P-TiC coatings were subjected to heat treatment at 400 °C for 1 h. The surface morphology, microstructural transformation, Vicker's microhardness, tribological and scratch resistance properties were studied with reference to the different carbide reinforcements as well as heat treatment. Inter-nodular space, craters and kinks are created due to the branching effect of nodules in the surface of the Ni-P-SiC (TiC) composite coatings. After the heat treatment, the matrix phase transformation was not altered due to the incorporation of SiC or TiC into the Ni-P coating; however, a slight increase in residual stress was identified from the XRD analysis. In addition, the content of carbon deposition was found to be higher in the matrix of Ni-P-SiC composite coating than that in the Ni-P-TiC coating. The agglomeration of SiC particles was higher than TiC particles in the coating matrix, which was also supported by the result of Zeta potential measurement. Heat treatment improved wear and coefficient of friction in the Ni-P-SiC and Ni-P-TiC composite coatings. Compared to Ni-P-SiC coating, Ni-P-TiC coating revealed the enhanced tribological and scratch resistance performance after the heat treatment.