Influence of the composition of titanium oxynitride layers on the fretting behavior of functionalized titanium substrates: PVD films versus surface laser treatments

In this work we compared the fretting behavior of pure titanium plates functionalized with titanium oxynitride surface layers, obtained by two methods: a Physical Vapor Deposition (PVD) method, reactive magnetron sputtering, and Surface Laser Treatments (SLT), under different mixtures of oxygen and nitrogen. The composition of the layers was determined by nuclear reaction analysis (NRA) and their structure was analyzed by Raman spectroscopy. PVD layers were TiN-like fcc layers, with an oxygen concentration going from 36 to 50 at.%. Three SLT layers were studied. The first one was a TiN-like layer containing similar to 28 at.% of oxygen. The second one was formed of different titanium oxide phases containing similar to 5 at.% of nitrogen. The third one was a titanium dioxide layer with a negligible concentration of nitrogen. It was found that the steady friction coefficient was similar for all the layers and quite lower than that measured for uncoated Ti. The study of the fretting scars revealed a higher resistance of SLT layers to fretting wear, which can be due to the smooth layer-substrate interface. The detachment of coating particles was observed in some PVD layers. Finally, the transfer of matter between the first bodies was studied by micro-Raman spectroscopy and nuclear reaction techniques: NRA and Particle Induced X-ray Emission. (C) 2014 Elsevier B.V. All rights reserved.