A thermo - Kinetic Study of Titanium Oxidation Assisted by a Nd - YAG Pulsed Laser

摘要

The nitriding or the carburation of a titanium substrate assisted by a laser source has been extensively studied, but these have been fewer investigations of laser induced oxidation phenomena. Taking account of the problem complexity due to the large number of possible oxidation stages, we have elaborated and carefully characterized the oxidized layers. Physico-chemical analysis (Auger and XPS), phase identification (XRD in θ - 2 θ and grazing mode), and morphological observations (SEM) have been performed. Elementary analyses using microprobe (EDS) and elementary nuclear analysis (NRA) have been undertaken to precisely determine the oxygen diffusion profile. Explanations of the formation of the oxidized compounds are suggested by reference to the Ti - O diagram. The thermal cycles undergone by the titanium substrate during the laser treatment have also been simulated to help clarify the role of the cooling rate as well as the repetition rate on the presence of some metastable phases. The aim of this study is the establishment of phase/structure mapping. This would allow a predictive analysis of the phases to be formed as a function of the laser treatment parameters and the reactive atmosphere conditions.