Characterization of composite titanium nitride coating prepared by reactive plasma spraying

Reactive plasma spraying (RPS) technology has been used to produce high thickness (> 100 mu m) 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.