Structure and wear properties of NiTi modified by nitrogen plasma immersion ion implantation

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 444; no. 1; pp. 192 - 197
• Main Authors: Liu, Xiangmei, Wu, Shuilin, Chan, Y.L., Chu, Paul K., Chung, C.Y., Chu, C.L., Yeung, K.W.K., Lu, W.W., Cheung, K.M.C., Luk, K.D.K.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-01-2007; Elsevier
• Subjects: Applied sciences; Contact of materials. Friction. Wear; Exact sciences and technology; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Nickel titanium shape memory alloy; Plasma immersion ion implantation; Structure; Wear; 81.40.Pq; Structure; Plasma immersion ion implantation; Nickel titanium shape memory alloy; Wear; Titanium alloy; Ion implantation; Pin on disk machine; Plasma assisted processing; Wear mechanisms; 81.40.Pa; Plasma immersion ion implantation; Nickel titanium shape memory alloy; Structure; Wear; Shape memory alloy; Friction; Abrasive wear; Friction coefficient; Wear resistance; Nickel alloy; Concentration distribution; X-ray photoelectron spectra
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2006.08.071

NiTi shape memory alloy samples were plasma-implanted with nitrogen at voltages ranging from −10 to −40
kV. X-ray photoelectron spectroscopy results disclose the formation of gradient TiN layers which thicknesses and elemental in-depth distributions depend on the applied voltages. The effects of the implantation voltages on the wear characteristics were investigated by pin-on-disk tests. In the initial period of our friction test, the implanted samples exhibit low friction coefficients compared to the untreated sample. The wear resistance of the plasma-implanted NiTi samples increases with implantation voltages and decreases with the applied loads. Our results reveal that the wear mechanism of the implanted samples is adhesive-dominant under low applied loads but becomes abrasive-dominant at high applied loads.