STUDY OF COLORATION ON EXCIMER LASER TREATED TITANIUM SURFACES

Surface oxidation of Ti was carried out using KrF excimer laser in the presence of O2. Different colors were obtained by varying the number of laser pulses at the fixed laser fluence. X-ray photoelectron spectroscopy shows that the outmost surface is composed of TiO2 and the inner layer consists of TiO and Ti2O3 as well as TiO2. Fractions of titanium chemical states stabilized at 33% TiO, 63% TiO2, and 2% Ti2O3 with increasing number of laser pulses. The surface roughness tends to increase with number of laser pulses. It is suggested that compositional variation and morphological difference contribute to the laser-induced surface coloration.