Ni-P-TiO_2 nanocomposite coatings with uniformly dispersed Ni_3Ti intermetallics: effects of TiO_2 nanoparticles concentration

摘要

Ni-P-TiO_2 nanocomposite coatings were electrodeposited on copper substrates and influence of TiO_2 nanoparticles concentration on the phase structure, morphology, chemical composition, microhardness, and corrosion behaviour of the coatings was investigated. Results demonstrate that Ni3Ti intermetallics form and grow during the electrodeposition of the coatings. This study is the first to report the formation of the intermetallics in the case of electrodeposited Ni-P alloy matrix composite coatings. Moreover, the formation mechanism of the intermetallics is discussed in detail. The formed intermetallics dispersed uniformly throughout the microstructure of the nanocomposite coatings, thereby playing a critical role in improving the mechanical and corrosion-related properties of the coatings. Ni-P-10 g-L~(-1) TiO_2 nanocomposite coating possessing the highest amount of Ni3Ti intermetallic associated with the lowest P content, thereby showing the superior microhardness and corrosion resistance. All in all, the volume fraction of Ni3Ti intermetallics is the dominant factor altering the various properties of the coatings.