Composition dependence of the initial oxidation behaviour of Ti1−xAlxN (x = 0.20, 0.45, 0.65) films studied by XAS and XPS
✍ Scribed by Esaka, F.; Furuya, K.; Shimada, H.; Imamura, M.; Matsubayashi, N.; Kikuchi, T.; Ichimura, H.; Kawana, A.
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 414 KB
- Volume
- 27
- Category
- Article
- ISSN
- 0142-2421
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✦ Synopsis
The difference in the initial oxidation behaviours of Ti 1-x Al x N (x = 0.20, 0.45, 0.65) films was studied by x-ray absorption (XAS) and by x-ray photoelectron spectroscopy (XPS) using synchrotron radiation (SR-XPS). The N K-edge XAS results indicated rapid decreases in the relative ratio of Al-N relative to the total nitride with surface oxidation for all the Ti 1-x Al x N films. The SR-XPS analysis of O, Ti and Al species with different photon energies disclosed the formation of Al 2 O 3 at an upper layer and TiO 2 at a lower layer in oxidized Ti 1-x Al x N films with x = 0.20 and 0.45. In contrast, a mixed Al 2 O 3 and TiO 2 surface layer was formed in the oxidized Ti 1-x Al x N film with high aluminium content (x = 0.65). In addition, N 2 molecules, which were formed as an intermediate species during the oxidation, were concentrated in the interface of Al 2 O 3 and TiO 2 in the oxidized Ti 0.55 Al 0.45 N and Ti 0.80 Al 0.20 N films, whereas they occurred near the surface in the oxidized Ti 0.35 Al 0.65 N film. From these results, it was concluded that the high surface oxidation-resistant properties of Ti 1-x Al x N film with low aluminium content originated from the rapid formation of a surface Al 2 O 3 layer that prevented inward diffusion of oxygen as well as outward diffusion of molecular nitrogen.