Changes in the Laser-Processed Ti6Al4V Titanium Alloy Surface Observed by Using Raman Spectroscopy

This works reports on the effects of treating the surface of Ti6Al4V titanium alloy samples with a laser with a wavelength of 1064 nm, operating in a pulsed and continuous mode. The obtained surfaces with different roughness, complexity and wettability were examined by Raman spectroscopy in order to recognize the presence of titanium oxides on the functionalized surface. The layer of titanium oxides on the surface with the identified rutile phase obtained by laser treatment in the continuous wave mode is a reason for a hydrophobic surface that appeared 50 days after the treatment process. In the case of the surface obtained by the pulsed laser process, only local points at which the Raman bands attributed to the metastable phases anatase and brookite of TiO₂ can be identified. In this treatment process, complete surface hydrophilicity was observed during 29 days after the functionalization process (maximal contact angle observed during this time was 68.4 deg). For some functionalization processes of different parameters, the contact angle remained immeasurable until 119 days after the functionalization process. In summary, Raman spectroscopy identifies surface changes of Ti6Al4V after laser processing.