Studying the effect of reducing agent on the coating of SiC ceramic particles by nickel electroless plating

Silicon carbide ceramic (SiC) has high hardness, excellent thermal shock resistance, low thermal expansion, high thermal conductivity, and good elastic modulus properties. So, it is used as a reinforcement to metal matrix composites. One of the problems of the industrial application of SiC in the production of composite materials is its non-uniform distribution and poor wettability by the melting of many metals. Among the many methods used today to solve this problem is the application of metal coatings such as nickel, copper, and so on by electroless plating on the surface of SiC particles. In this paper, it has been tried to study the effect of reducing agents (hydrazine, hypophosphite, borohydride) on the coating of SiC particles. Studies have shown that copper-matrix composites containing Ni-coated SiC reinforcing particles have ۴۰% higher wear resistance than uncoated particle-reinforced composites, and this is due to the stronger interfacial bonding between the substrate and the coated reinforcement. In addition, by adding one percent of coated particles to the metal base, the amount of microhardness has increased up to ۲۵%. By increasing the amount of the reducing agent, the grain size and thickness of the coating on the surface of SiC particles increases. Sodium borohydride is a more suitable option compared to other nickel salt reducing agents, and studies have shown that if the amount of salt and the sodium borohydride reducing agent in the plating bath is a ۱:۱ ratio, better coverage will be obtained. The best conditions for optimal layering and creating a uniform nickel coating on the surface of SiC ceramic powders with dimensions of ۱۵ microns have been created at the bath temperature of ۸۵°C and the pH of ۱۳.

کلیدواژه ها:

Coating of SiC particles ، Ni electroless plating ، Reducing agents ، Sodium borohydride.