Development of electromagnetic acceleration plasma generator for titanium nitride coatings

Electromagnetic acceleration plasma generators, which are called magneto-plasma-dynamic (MPD) arcjet generators, can produce higher-velocity, higher-temperature and higher-density plasmas than those of conventional thermal plasma torches, because MPD arcjet plasma is efficiently accelerated by electromagnetic body forces in MW-class input power operation. These properties are effective for deposition of rigid films adhering strongly to substrate surfaces. In this study, we developed a reactive spray process of titanium nitride film deposition using MPD arcjet generators. The MPD arcjet generators had titanium cathodes, and their working gas was nitrogen. The phase structure and the composition of the titanium nitride films were analyzed by means of X-ray diffraction (XRD) and scanning electron microscopy, and the Vickers hardness of the titanium nitride films was also measured. XRD analysis showed that TiN ratio was highly sensitive to the cathode diameter and the discharge current. The Vickers hardness reached about 1000 at the substrate center. (C) 2000 Elsevier Science Ltd. All rights reserved.