Characterization of composite titanium nitride coatings prepared by reactive plasma spraying

Reactive plasma spraying (RPS) technology has been used to produce high thickness (>100 μm) films of composite Ti–TiN–TixNy coatings. Reactively sprayed coatings obtained from SP700 (Ti–4.5Al–3V–2Mo–2Fe) and Ti6242 (Ti–6Al–2Sn–4Zr–2Mo) powders, deposited onto flat substrates of Ti–6Al–4V, have been investigated. X-ray diffraction (XRD) and micro-hardness measurements have been used to characterize the crystallographic features and differences between the hardness of cross-section and surface. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) techniques have been used to determine the morphology and surface chemical composition of the coatings. Back-scattered electron imaging has revealed the distribution of Ti and TiN in the composite material. Obtained results evidenced a sharp interface between the coating and substrate in terms of the profile of chemical composition. The presence of unmelted Ti particles as well as the formation of nitrides was observed.