The early stage of the laser-induced oxidation of titanium substrates

Commercially pure titanium substrates have been treated using Q-switched Nd:YAG laser radiation (τ=50 ns, λ=1.06 μm). The repetition of laser shots at the same location induces thermal cycling which leads to progressive oxidation and to the formation of multilayered coatings . Previous studies have given us an overview of the various titanium oxides which could be formed as a function of the laser treatment parameters. This work focuses on the very early stage of the laser-induced oxidation, when the oxygen content does not exceed 50 at.% (TiO). The treated layers have been characterized by optical and SEM observation, EDS and X-ray diffraction analyses. The presence of the different new structures has been examined in relation with the Ti–O phase diagram.