Face-Centered Cubic (Al1-xCrx)2O3 Thin Films: Deposition and Characterization Studies
2011 (English)Conference paper, Presentation (Other academic)
Face centered cubic (Al1-xCrx)2O3 solid solution films, with x in the range 0.60<x<0.70, have been deposited usingdual reactive RF magnetron sputtering from Al and Cr targets in mixed Ar/O2 discharge at a substrate temperatureof 500 °C. The films have a strong <100> preferred orientation. The unit cell parameter is 4.04 Å determined byx-ray diffraction and high resolution transmission electron microscopy techniques. The (Al1-xCrx)2O3 films aresuggested to have a non-stoichiometric NaCl structure with 33% vacancy occupancy on Al/Cr sites.Nanoindentation shows that the films exhibit hardness values up to 26 GPa and reduced modulus of 220-235 GPa.In the present work, in-situ annealing studies were performed on as-deposited samples for a series of temperaturesup to 1100°C and annealing time of 8 h. The results show that fcc structure remains intact up to 950°C. A gradualphase transformation from fcc to corundum at 1000°C is observed, where annealing for 1-3 h yields a partialtransformation and annealing for > 4 h results in complete transformation to alpha-(Al1-xCrx)2O3. There is noindication of any phase separation into alpha-Cr2O3 and alpha-Al2O3.
Place, publisher, year, edition, pages
National CategoryManufacturing, Surface and Joining Technology Physical Sciences
IdentifiersURN: urn:nbn:se:liu:diva-84375OAI: oai:DiVA.org:liu-84375DiVA: diva2:558843
International Conference on Metallurgical Coatings and Thin Films (ICMCTF 11), 2-6 May, San Diego, USA