Surfaces of complex alloys
Surface structure, thin films and coating technologies.
High hardness combined with low friction properties have been put forward for quasicrystal and CMA which makes them interesting candidates for anti-adhesive of tribological coatings. Coating of materials with CMA has been thus the subject of intense researches in the last ten years. Five of the European Integrated Center partners are participating to the AppliCMA project funded by the EC (FP7).
The research on coatings encompasses two aspects: processing science and properties determination. These two aspects correspond to the processing-structure and to the structure-properties relationships, respectively.
Film processing has been carried out using either MOCVD or PVD techniques. MOCVD applied to CMA is an entirely new field for which a large processing development has been necessary [1-2].
The main properties of interest which are currently studied are:
(i) Wetting and friction, related to the potential tribological application [3, 4].
(ii) Coating surface reactivity, for anti-corrosion coating applications .
Finding interesting new coatings with specific properties is time consuming owing to the very large phase field landscape in ternary or quaternary phase diagrams. A way to rationalize the search for new materials is by using high throughput techniques such as the combinatorial approach. A fast screening approach based on structure/properties mapping of thin film samples with composition gradient has been proposed and tested (see Figure). Analysis of results using dedicated data-mining software needs to be developed.
Figure 1: Demonstrator experiment where the wetting properties have been measured on a compositional gradient (x-y) coated sample. The bestcomposition is easily found.
1. T.C. Xenidou, N. Prud’homme, C. Vahlas, N. Markatos, A.G. Boudouvis., Parametric study of Al MOCVD process using an advanced reactive transport model based on targeted growth experiments. J. Electrochem. Soc., 2010, 157(12), D633-D641.
2. V.V. Krisuyk, A.N. Gleizes, L. Aloui, A. Turgambaeva, B. Sarapata, N. Prud’homme, F. Senocq, D. Samélor, A. Zielinska-Lipiec, D. deCaro, C. Vahlas. Metalorganic chemical vapor deposition of iron-containing films from novel amidinate precursors. J. Electrochem. Soc, 2010, 157(8), D454-D461.
3. Complex Metallic Alloys: fundamental and applications, J.M. Dubois and E. Belin-Ferré editors, Willey-VCH, 2011, 409 Pages
4. S. Achanta, M. Feuerbacher, A. Grishin, X. Yea, J.-P. Celis, On the mechanical and tribological behavior of Al3Mg2 complex metallic alloys as bulk material and as coating, Intermetallics, 2010, 18, 2096-2104