TRIBOLOGICAL PROPERTIES AND CORROSION RESISTANCE OF NANODIAMOND REINFORCED COMPOSITE COATINGS ON NITI ALLOYS

摘要

Ni-P/nanodiamond (ND) nanocomposite coatings with various ND contents were prepared by electrodeposition in Ni-P electrolyte containing different concentration of ND particles. The effects of ND particles on the composition, structure, distribution of ND and microhardness of nanocomposite coatings were investigated. The results showed that co-deposited ND was uniformly distributed in the Ni-P matrix, and led to the changes in the composition and structure of Ni-P/ND composite coatings, contributing to the increase of the microhardness of Ni-P/ND nanocomposite coatings compared with the Ni-P coating. The corrosion behavior of Ni-P and Ni-P/ND nanocomposite coatings was evaluated by polarization curves and electrochemical impedance spectroscopy in artificial saliva at 37°C. It was found that the introduction of ND in Ni-P matrix increased the corrosion resistance. Ni-P and Ni-P/ND nanocomposite coatings prepared from electrolyte containing 0.5-8.0 g/L ND exhibited active-passive transition, while Ni-P/ND nanocomposite coatings obtained from electrolyte with ND concentration of 15.0 g/L behaved active dissolution. In general, Ni-P/ND nanocomposite coatings obtained from Ni-P electrolyte containing 8.0g/L ND exhibited excellent wear and corrosion properties.