Tribo and Corrosion Resistance of Ni–W–P Coatings Synergistically Enhanced by Cationic hBN and Cationic cBN

In this work, polydopamine (PDA) modification of hBN is used to create DRhBN⁺ particles having a two-dimensional lamellar structure, which are then applied on Ni–W–P coatings. Additionally, pulsed electrodeposition is used to successfully create composite coatings of Ni–W–P/DRhBN⁺, Ni–W–P/DRcBN⁺, and Ni–W–P/DRhBN⁺–DRcBN⁺. The properties of the four composite coatings are contrasted. The results demonstrate that the PDA coating on hBN particles improves the dispersion of DRhBN⁺ particles in the bath by introducing −NH₃⁺ and catechol groups. Moreover, because of the grain refinement impact of the DRhBN⁺ and DRcBN⁺ particles, the surface of the composite coating with these additions is dense and flat. It should be noted that the innovative composite coating, which takes advantage of the synergistic effects of the two modified particles, performs best overall. According to microhardness tests, the composite coating may reach a hardness of up to 917.6 HV. Surprisingly, the friction loss of the composite coating during reciprocating friction testing is negligible, and its average coefficient of friction (COF) is as low as 0.199. The DRhBN⁺ and DRcBN⁺ particles’ diffuse reinforcement, their effect on grain refinement, and the DRhBN⁺ particles’ self-lubricating ability as a solid lubricant are all responsible for the improved performance. Electrochemical impedance spectroscopy and polarization curve tests further demonstrate that the composite coating, which combines both kinds of particles, has an i_corr of 1.34 μA/cm², a corrosion rate of V_corr 14 μm/year, and an R_t value of 54230 Ω·cm². These findings demonstrate the exceptional corrosion resistance of the Ni–W–P/DRhBN⁺–DRcBN⁺ composite coating.