Influence of residual stress on corrosion and mechanical properties of silicon carbide-reinforced nickel-tungsten coatings

Abstract

Nickel-tungsten (Ni-W) coatings reinforced with silicon carbide (SiC) were successfully produced on a steel substrate using the pulse electrodeposition method (PED). Influence of SiC addition on phases, crystallite size, dislocation density, residual stress, mechanical properties and corrosion resistance of the coating were investigated. Field emission scanning electron microscopy (FESEM) images revealed a refinement in the coating's surface morphology and distribution of SiC particles. Higher residual stress observed in the as-deposited Ni-W coating was attributed to hydrogen dissolution into the coating, leading to lattice expansion, with the subsequent release of hydrogen, contributing to this stress. Addition of SiC to the Ni-W coating resulted in improvements in hardness and bonding strength by similar to 23% and similar to 184%, respectively. Moreover, the addition of SiC to Ni-W coating led to a reduction in the coefficient of friction by about similar to 34% compared to Ni-W coating. Corrosion properties were evaluated using an immersion test in a 3.5 wt.% NaCl solution. The Ni-W-SiC composite coating exhibited significantly higher corrosion resistance, with similar to 67% decrease in corrosion rate compared to Ni-W coating. This enhanced corrosion resistance was linked to the grain refinement induced by SiC, which restricted the penetration of corrosive ions onto the substrate. Furthermore, the formation of a continuous barrier layer composed of SiO2, contributed to the improved corrosion resistance.