Electroless nickel–phosphorus plating on silicon carbide particles for metal matrix composites

In this work, a nickel–phosphorus (Ni–P) coating was deposited on the surface of silicon carbide (SiC) particles through electroless nickel (EN) deposition. The influences of main effective parameters, including NaH2PO2·H2O/NiSO4·6H2O molar ratio, dl-C4H6O5/NiSO4·6H2O molar ratio, pH and bath temperature, were investigated by the Taguchi design method. Subsequently, the optimized bath parameters for EN plating on SiC particles were further investigated by considering the balance between plating rate (R) and bath efficiency based on a series of experiments. The morphology and phase structure of the coating fabricated by the optimal bath were characterized. Thermal stability of the Ni–P coated SiC particles was also analyzed. The results showed that a more stable bath with relative maximum nickel R of 11.28% on the surface of SiC particles was obtained. As a result of this optimized bath, a continuous and uniform coating with an X-ray amorphous structure, around 1.2 μm thickness, was fabricated on the SiC particles. Thermal analysis suggested that the EN coated SiC particles have a relative higher thermal stability than the original ones. Meanwhile, the coating formation mechanism for EN coating on SiC particles was discussed based on the morphologies in different deposition stages. Such EN plating can be successfully applied in the surface modification of ceramic particles, which favors the development of metal matrix composites.