High-energy x-ray diffraction was utilized to study in situ the formation temperature and crystal structure of the rhombohedral phase In4 Sn3 O12. The kinetics of In4 Sn3 O12 formation from bixbyite In2 O3 and tetragonal SnO2 nanopowders were investigated during isothermal annealing treatments ranging from 1335 to 1400 °C. The transformation data exhibited two regimes, well described with a two-exponent kinetics model. The first regime followed a Johnson-Mehl-Avrami-Kolmogorov (JMAK) behavior until 75% of the In4 Sn3 O12 phase formed and was modeled with a modified JMAK equation. The formation of the first grains of In4 Sn3 O12 at 1345 °C was observed in situ using diffraction two-dimensional images. Structural results obtained from Rietveld analysis include atomic positions, phase analysis compositions of the samples, and lattice parameters during heating, cooling, and isothermal conditions. Linear and volume coefficients of thermal expansion were determined for the In4 Sn3 O12 phase.
ASJC Scopus subject areas
- Physics and Astronomy(all)