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Ti2AlN thin film formation by multilayer and nitriding approaches

Vincent Dolique 1Thierry Cabioch Michel Jaouen Frédéric Pailloux Philippe Guerin Michel Drouet 

1. University of Poitiers Laboratoire Metallurgie Physique (LMP), Bld Marie et Pierre Curie Chasseneuil du poitou, Poitiers 86192, France

Abstract

Ti2AlN belongs to a novel class of nanolaminated materials: the MAX Phases. Up to now, several approaches were used to synthesize MAX phases under bulk forms but their synthesis as thin films remains poorly documented. Two research groups recently demonstrated that Ti2AlN thin films formation can be achieved by high temperature magnetron sputtering processes. Here, alternative approaches are described. The first one is a two-step technique based on the deposition of a TiAl/TiN multilayer followed by a thermal annealing. Multilayers were deposited by dual ion beam sputtering at room temperature. Theses samples were then annealed (600°C and 780°C) to allow atomic diffusion and Ti2AlN formation. HRTEM observations and EELS spectra were recorded prior and after the thermal treatment. The progressive formation of Ti2AlN during the annealing was evidenced both from in situ plane view TEM and XRD observations. Our results suggest that nitrogen diffusion into the TiAl sublayers allows the formation of the MAX phase whereas the Al atoms in excess presumably out diffuse towards the TiN sublayers where they are inserted as interstitials. The second approach consists in a direct formation of Ti2AlN by plasma nitriding of TiAl bulk substrates or thin films deposited by magnetron sputtering onto Si and TiAl substrates at room temperature. TiAl bulk substrates and thin films were then exposed to nitrogen plasma at 900°C during 2 hours. HRTEM observations and XRD spectra reveal that this procedure allows the MAX phase formation whatever the substrate is. Of interest, TiN formation was never observed. Furthermore, XRD analysis shows that (0002) textured Ti2AlN thin films are obtained when TiAl layers are nitrided. The Ti2AlN formation by nitriding will be discussed on the basis of XRD, TEM but also glow-discharge spectrometry experiments.

 

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Related papers

Presentation: Oral at E-MRS Fall Meeting 2006, Symposium A, by Vincent Dolique
See On-line Journal of E-MRS Fall Meeting 2006

Submitted: 2006-05-12 12:33
Revised:   2009-06-07 00:44