Berlin 2018 – scientific programme

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DS: Fachverband Dünne Schichten

DS 6: Thin Film Applications

DS 6.10: Talk

Monday, March 12, 2018, 17:30–17:45, H 0111

Magnetron sputtered refractory metal thin films on NiTi and their influence on the phase transition behaviour of NiTi — •Fabian Seifried¹, Helmut Riedel², Harald Leiste¹, Ruth Schwaiger¹, Sven Ulrich¹, Hans Juergen Seifert¹, and Michael Stueber¹ — ¹KIT IAM-AWP, Eggenstein-Leopoldshafen, Germany — ²TU Wien WWWT, Wien, Austria

In this study, pseudo-elastic Ni 50.8 at.%-Ti alloy sheets of 1000 microns thickness were coated with 10 microns thick refractory metal thin films, by non-reactive d.c. magnetron sputtering. These thin films were characterized with regard to their microstructure and selected mechanical properties. Microstructural characterization of the thin films included X-Ray Diffraction and Scanning Electron Microscopy analyses. Mo thin films grow in a densely packed, (110) textured b.c.c. structure with columnar grains on the NiTi substrate. Ta and Nb thin films grow as well in a dense columnar structure; however they show X-Ray diffraction peaks of various lattice planes of the b.c.c. structures (i.e. no texture). Considering the specific thin film/substrate thickness ratio (1:100) of the samples, the mechanical properties of both the thin films and thin film/substrate composites were investigated on different length scales, using nano- and microindentation techniques. To evaluate the potential impact of the surface coating and the deposition process on the phase transformation behaviour of the NiTi shape memory alloy, differential scanning calorimetry analyses were done. Conclusions and recommendations will be given for potential thin film materials as radiopaque coatings on NiTi substrates for medical applications.