Effect of Particle Concentration on the Microstructure and Properties of Electrodeposited Nickel–Diamond Composite Coatings

For the purpose of improving the wear properties of Ni composite coatings, diamond particles were co-electrodeposited into Ni–diamond composite coatings. The effect of diamond particle concentration in the electrolyte on the surface morphology, microstructure, and wear properties of Ni–diamond composite coatings was investigated. The electrodeposition behaviors of the composite coatings were simulated by COMSOL5.6. The results showed that the content of diamond particles in the coating was elevated by increasing the particle concentration in the electrolyte. The formation of [200] fiber texture was blocked and concurrently brought about crystallite refinement of the Ni deposits by the embedded particles. The COMSOL simulation findings indicated that embedded particles influenced the microstructure of the Ni deposits through processes such as heterogeneous nucleation, rearrangement, and concentration of local current density. The synergistic effect of the tailored microstructure and embedded particles substantially enhanced the wear resistance of the coating. By increasing the particle concentration in the electrolyte, the wear resistance of the coating was gradually enhanced, and the coating electrodeposited at 16 g/L possessed the lowest friction coefficient and the smallest profile of wear scratch owning to the strengthened synergistic effect.