Characterization of composite titanium nitride coatings prepared by reactive plasma spraying

Abstract

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. (C) 2005 Elsevier Ltd. All rights reserved