Effect of compact structure on phase transformation kinetics from anatase phase to rutile phase and microstructure evolution during sintering of ultrafine titania powder compacts

The effect of compact structure both on phase transition kinetics and on the densification during sintering of n-TiO₂ compacts has been investigated. The compact structures varied from loose powder pack to very high density using different compaction pressures. The compact structure is verified to significantly affect phase transition kinetics and densification during sintering. The onset temperature of anatase -> rutile phase transition decreased with the increase of the compact density. The highest density compact of 86.9% showed phase transition at the lowest temperature and no detrimental effect on densification. The compact structure, i.e., the coordination number of particles in the compacts, is considered to significantly affect both the phase transition kinetics and the subsequent densification during the sintering of n-TiO₂ compacts.