Tribology and corrosion properties investigation of a pulse electrodeposition duplex hard-particle-reinforced Ni-Mo nanocomposite coating

摘要

In this work, Ni-Mo-SiC-TiN composite coatings were prepared by pulse electrodeposition. Through analyzing the effect of particle content on the phase structure and morphology of NiMo coatings, the relationship between nanoparticles co-deposition amount and the mechanical properties and corrosion resistance of Ni matrix composite coatings was evaluated. The results show that the coating prepared at an electrolyte concentration of 20 g/L is flat and dense presenting the highest particle content. The crystallite size ranging from 28.27 nm to 11.85 nm is affected by different nanoparticle concentrations. As shown by the Tafel polarization and wear test, the incorporation of two hard particles improved the coating performance, and the corrosion current density was reduced by 74% to 1.84 mu A/cm(2). The wear rate decreased from 10.196 x 10(-4) mm(3)/N.m to 2.65 x 10(-4) mm(3)/N.m, and the average friction coefficient decreased to 0.11. The duplex hard particles play a bearing and hindering role during friction and corrosion. Based on the co-deposition kinetic model, a five-step pulse deposition model referring to nanoparticles was established. It is found that SiC/TiN particles co-deposited to the preferential Ni (111) crystal face and subordinate Ni (200) face. And the good binding ability between the matrix and the nanoparticles results in a high load transfer effect, thus enhancing the tribological properties of the coating. Moreover, the interaction between the duplex nanoparticles was further discussed.