Kinetics of Phase Transformation in fcc-(Al0.32Cr0.68)2O3 Thin Films
(English)Manuscript (preprint) (Other academic)
Thermal stability of fcc-(Al0.32Cr0.68)2O3 thin film is investigated by ex-situ annealing of films in the temperature range of 500-1100 °C and annealing times of 2-10 h. X-ray diffraction indicates that the phase transformation from fcc to corundum crystal structure starts at 925 °C and completes at 1000 °C. This is further confirmed by high resolution transmission electron microscopy and selected area electron diffraction. The kinetics of phase transformation is analyzed by Johnson-Avrami-Mehl model. The phase transformation from fcc to corundum in (Al0.32Cr0.68)2O3 thin films is a two-stage thermally activated process. The first stage is phase transformation and has the apparent activation energy of 213±162 kJ/mol (0.44±0.34 eV/atom). This is followed by a second stage with a larger apparent activation energy of 945±27 kJ/mol (1.96±0.06 eV/atom). This is likely associated with the grain growth of a-phase upon completion of the phase transformation.
IdentifiersURN: urn:nbn:se:liu:diva-65699OAI: oai:DiVA.org:liu-65699DiVA: diva2:398419