Titanium-based films deposited using a Nd:YAG pulsed laser

Abstract

Complex examinations were performed of the structure of films of metallic titanium, titanium nitride and titanium oxide deposited by means of PLD with a Nd:YAG laser. The influence of the deposition parameters on the film morphology was examined. The films revealed a nano-structure of good quality. A new tetragonal Ti(N) phase was revealed in the deposition of metallic titanium in a reactive chamber with an argon atmosphere. The TiN phase was formed during deposition of titanium nitride, independently of the nitrogen flow in the chamber. The transition of oxides from Ti2O via TiO to TiO2 was observed with an increasing flow of oxygen in the chamber for deposition of titanium oxide. TEM examinations of the microstructure in cross-sections of the film revealed a micro- columnar structure. All the examined films were characterised by a strong axial crystallographic preferred orientation on the basis of the measured pole figures. The axial texture was identified within the deposited metallic titanium for the Ti(N) tetragonal phase as well as for the TiO oxide, while the texture was observed in the case of TiN nitride. Measurements of the residual stresses of the first order in the TiN phase, by using the X-ray sin2ψ method, showed stress levels of -5000 to -7000 MPa. The residual stresses measured in the substrate of ferritic steel were about -150 MPa.