Surface characterization of C/Ti-6Al-4V coating treated with ion beam.

Surface of titanium alloy (Ti-6AI-4V) has been modified by ion beam mixing of thin C film. X-ray photoelectron spectroscopy analysis showed that after mixing, the surface film consists essentially of a Ti compound containing (Ti, O and C), TiO2, Ti and C contamination. The composition of the surface modified film determined by Rutherford backscattering spectrometry is approximately Ti0.5O0.3C0.2 and its thickness is about 200 nm. After three months immersion in a simulated body fluid, the growth of calcium phosphate species containing both HPO4- and H2PO4- (probably CaHPO4 and Ca(HPO4)2) have been observed. Titanium is found to be essentially composed of the Ti compound after immersion suggesting that both metallic Ti and TiO2 have dissolved.