The re-strengthening effect of a quenching process on the mechanical and tribological performance of electrodeposited Ni-P coatings on steel substrates

Abstract

Ni-P alloy coatings with a phosphorus content of 4.44 wt% were prepared by the direct current electrodeposition technique. After being annealed at 400 °C, all the Ni-P coatings mainly exhibited a nanocrystalline structure comprising nanocrystalline Ni and Ni3P precipitates. The Ni-P coatings were further subjected to quenching treatment at various temperatures. The effects of the quenching process on the microstructural evolution and tribological properties of the Ni-P coatings were investigated. A further quenching process at 400 °C caused a decrease in grain size as well as increases in hardness and wear resistance, which was attributed to the re-strengthening effect of the combination of the grain refinement effect and the dispersion of Ni3P. The wear resistance of the quenched Ni-P coatings increased with a decrease in grain size in accordance with the inverse Hall-Petch relationship.