2017 Volume 1 Pages 9-16
In this study, TiO2–VO2 solid solutions were heated by microwaves and by an electric-furnace to investigate the spinodal decomposition behavior of a TiO2–VO2 system. Single-mode and multi-mode type microwave irradiation devices were used to investigate the spinodal decomposition of TiO2–VO2 . In the conventional process, spinodal decomposition required 12 h of annealing. However, in the microwave process, spinodal decomposition proceeded at a low temperature for 30 min. Additionally,the metal–insulator transition temperature (TMI ) of the prepared sample was lower than that of pristine VO2. This indicated the existence of an isotropic pressure on the boundary between the Ti-rich phase and the V-rich phase. Furthermore, the microwave-irradiated samples exhibited broadened double endothermic peaks in the DSC profiles. The broad peaks indicated that the samples exhibit several values of T MI , implying variations in the composition of the V-rich phase. The phase variation resulted from the selective heating of the V-rich layer that induced one-directional material diffusion from the V-rich phase to the Ti-rich phase.