Surface modification of Ti by an Ar-O mixture dc plasma

Titanium surface oxidation deserves a growing interest in biomedical engineering due to its biocompatibility enhancement and mechanical performance. In this work we report on the Ti surface modification, conducted into a toroidal vacuum vessel, by a DC plasma formed by an oxygen‐argon (20/80) mixture. By varying the gas pressure within the 2.5 to 5×10–3 mbar interval at the sample bias voltage –3000 V, we have gained control over the sample temperature up to the order of 650°C. In turn, the composition of the modified surface has been controlled by adjusting the flow rates of the gas mixture and the above mentioned temperature. The samples were characterised by microhardness tests, SEM, XRD and Raman spectroscopy. The diagnostics revealed a rutile TiO2 and TiO1.04 phase content in the modified layer. The remarkable effects of Ti sample temperature and treatment time on the morphology of the surface structure were explored. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)