Open Access
Article Number 05020
Number of page(s) 6
Section Applied Research and Applications: Engineering Materials with MT
Published online 01 September 2009
ESOMAT 2009, 05020 (2009)
DOI: 10.1051/esomat/200905020

Surface modification of Ni-Ti alloy by low-temperature nitriding process

J. Lelatko1, T. Goryczka1, T. Wierzchoń2, M. Ossowski2, B. Łosiewicz1, E. Rówiński1 and H. Morawiec1

1  Institute of Material Science, University of Silesia, 40-007 Katowice, Poland
2  Warsaw University of Technology, Faculty of Materials Science and Engineering, 02-507 Warsaw, Poland

Published online: 1 September 2009

In order to create new applications and enhance the performance of NiTi alloys, surface modifications are important to improve their biocompatibility. TiN coatings, due to its low chemical reactivity, high hardness and resistance to wear and corrosion, have been adopted for protecting surface of the NiTi alloys. In presented work the structure of layers formed at surface of the NiTi alloy was reported. The layers were formed using glow discharge technique at low temperature: 300 - 400°C. Thickness, surface roughness, interface roughness, density were calculated using reflectivity measurement. The X-ray grazing diffraction was applied for phase analysis. The chemical composition was determined using the XPS method. Corrosion resistance was studied applying the potentiodynamical method. Electrochemical characteristics of the samples were measured at the room temperature in Tyrod’s solution. Results have shown that low temperature nitriding produced the layers, which consisted from the nanocrystalline TiN phase. Relatively high values of corrosion and breakdown potentials proved that the TiN layers as well as the intermediate Ti3Ni phase effectively protect surface of the NiTi alloys against nickel ion release.

© Owned by the authors, published by EDP Sciences 2009