Influence of SiO2 nano-particles on microstructures and properties of Ni-W-P/CeO2-SiO2 composites prepared by pulse electrodeposition

Ni-W-P base composites containing CeO2 and SiO2 nano-particles were prepared on common carbon steel surface by pulse co-deposition of Ni, W, P, CeO2 and SiO2 nano-particles. The influence of SiO2 concentrations in bath on microstructures and properties of Ni-W-P/CeO2-SiO2 composites was studied, and the characteristics were assessed by chemical compositions, element distribution, surface morphologies, deposition rate and microhardness. The results indicate that when SiO2 concentration in bath is controlled at 20 g/L, the composites possess the fastest deposition rate, the highest microhardness, compact microstructures, smaller crystallite sizes and uniform distribution of W, P, Ce and Si within Ni-W-P matrix metal. Increasing SiO2 concentration in bath from 10 to 20 g/L leads to the refinement in grain size and the inhomogeneity of microstructures. While when SiO2 concentration is increased to 30 g/L, the crystallite sizes increase again and some bosses with nodulation shape appear on the surface of composites.