Electrodeposition of Ni–B/SiC composite films with high hardness and wear resistance

Abstract Ni–B/SiC composite films were electrodeposited using conventional Ni electrodeposition baths containing trimethylamine borane and SiC particles. In the present study, we examined the effect of SiC particle size, concentration of SiC particles in electrodeposition baths, thermal treatment, and current density on the properties (i.e., film hardness, SiC content, crystallite structure, and wear resistance) of the electrodeposited Ni–B/SiC composite films. The hardness of the composite films depended on the concentration of SiC particles in the baths; baths containing 1 and 8 g/L of SiC particles provided Ni–B/SiC films with a film hardness of 760 and 858 HV, respectively, which is because the SiC content in the composite films increased with increasing SiC particle concentration in the baths. Current density also affected the hardness of the composite films because both the SiC content and hardness of the Ni–B matrix changed with current density. Thermal treatment at 573 K in air had a significant influence on film hardness; for example, the hardness of Ni–B/SiC composite films was changed from 845 HV to 1499 HV after the thermal treatment. XRD patterns of the composite films revealed that thermal treatment results in a structural change of the Ni–B matrix from an X-ray amorphous structure to a crystalline Ni metal and Ni3B alloy, which leads to hardening of the composite films. Moreover, the Ni–B/SiC composite film showed higher anti-wear performance than Ni/SiC and Ni–P/SiC.