Preparation and characterization of Ni-P-nanoTiN electroless composite coatings

Ni-P-nanoTiN composite coatings were prepared successfully by electroless plating technique on AZ31 magnesium alloys. The composition, morphology, structure and phase transformation behaviour of the composite coatings were characterized respectively by using of scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray diffractometer (XRD). The micro-hardness and wear resistance of the nano composite coatings, both in as-deposited and heat treated states, were investigated. The results demonstrated that the composite coatings, which contained nano TiN particles, exhibited much better properties in hardness and wear resistance than the conventional Ni-P coatings and original AZ31 magnesium alloys. These enhancements of properties are attributed to the nano TiN particles uniformly distributed in the Ni-P matrix.