| AVS 63rd International Symposium & Exhibition | |
| Surface Science | Monday Sessions |
| Session SS+AS+HC-MoA |
| Session: | Metals, Alloys, and Oxides: Reactivity and Catalysis |
| Presenter: | Martin Wiesing, University of Paderborn, Germany |
| Authors: | M. Wiesing, University of Paderborn, Germany T. de los Arcos, University of Paderborn, Germany G. Grundmeier, University of Paderborn, Germany |
| Correspondent: | Click to Email |
The thermal oxidation of Ti0.5Al0.5N hard coatings as deposited by High Power Pulsed Magnetron Sputtering was investigated at reduced oxygen partial pressures of 10-6 and 10-2 Pa in a temperature range from 298 to 800 K. Quasi in-situ X-ray Photoelectron Spectroscopy and Low Energy Ion Scattering studies revealed oxygen to bind selectively to Ti-sites on the surface [1] and oxygen migration into the near-surface region. Three dimensional oxidation leads to the formation of a double layered surface oxide including a TiAl(O,N) growth region [2] terminated with a TiIV containing surface oxide [3]. Based on Wagner plot analysis, the surface oxide layer formed at 800 K can be described by a mixed TiIVAlIIIOx phase while a separated (TiIVO2)(AlIII2O3) phase preferentially forms at 298 K. Complementary Ultraviolet Photoelectron Spectroscopy revealed a high degree of nitrogen doping in both cases.
The results are of importance for the design of multi-layered nitridic hard coatings and for a thorough understanding of the high-temperature oxidation resistance of such coatings.
Acknowledgement: The authors gratefully acknowledge the German Research Foundation (DFG) for financial support (SFB‑TR 87). We thank Prof. Dr. J. Schneider and Holger Rueß for providing the coated specimen.
References:
[1] C. Kunze, D. Music, M. to Baben, J.M. Schneider, G. Grundmeier, Temporal evolution of oxygen chemisorption on TiAlN, Appl. Surf. Sci. 290 (2014) 504–508. doi:10.1016/j.apsusc.2013.11.091.
[2] S. Hofmann, Formation and diffusion properties of oxide films on metals and on nitride coatings studied with Auger electron spectroscopy and X-ray photoelectron spectroscopy, Thin Solid Films. 193–194, Part 2 (1990) 648–664. doi:10.1016/0040-6090(90)90216-Z.
[3] C. Gnoth, C. Kunze, M. Hans, M. to Baben, J. Emmerlich, J.M. Schneider, G. Grundmeier, Surface chemistry of TiAlN and TiAlNO coatings deposited by means of high power pulsed magnetron sputtering, J. Phys. Appl. Phys. 46 (2013) 084003. doi:10.1088/0022-3727/46/8/084003.