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Advances in Materials Science and Engineering
Volume 2014 (2014), Article ID 363917, 8 pages
http://dx.doi.org/10.1155/2014/363917
Research Article

NiTi Intermetallic Surface Coatings by Laser Metal Deposition for Improving Wear Properties of Ti-6Al-4V Substrates

1Council of Scientific and Industrial Research, National Laser Centre, Building 46F, P.O. Box 395, Pretoria 0001, South Africa
2Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, PMB X680, Pretoria 0001, South Africa

Received 24 October 2013; Accepted 4 February 2014; Published 17 March 2014

Academic Editor: Feng Zhao

Copyright © 2014 Mokgadi Nomsa Mokgalaka et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The NiTi intermetallic possesses a number of good properties, such as high wear, oxidation, and corrosion resistance. This paper focuses on the deposition of NiTi intermetallic coatings on Ti6Al4V substrate by laser melting of Ti and Ni elemental powder mixtures. The effect of varying the Ti content in the NiTi composition on the microstructure and wear properties of the coatings was investigated. The microstructure of the NiTi intermetallic coatings were characterized by the scanning electron microscope (SEM) equipped with Energy Dispersive Spectroscope (EDS). The wear properties of the coatings were performed under accelerated dry sliding wear tests. The results obtained from the SEM/EDS analysis; show that the coatings consist of Ni and Ti elements from the feedstock, and the NiTi, NiTi2 and NiTi3, intermetallic phases. Dry sliding wear analysis revealed that there is correlation between the hardness and the wear rate. The coatings displayed significant improvement in wear resistance up to 80% compared to the substrate.