1981 Volume 89 Issue 1027 Pages 140-147
The relationship among the sinterability, the particle size and the sintering mechanism were studied by using the TiO2 powder prepared by the oxidation of TiCl4 in vapor phase.
The relative density of sintered pellets increased with decreasing the particle size of TiO2 powder. The relative density of sintered pellet from the powder with average particle size of 0.06μm went up to 100% by sintering at 1200°C for 2h in air. The sintering of fine powder whose particle size are less than a few thousands Å proceeded via two densification processes, that is, the rapid densification by rearrangement of primary particles at above 750°C and the slow densification by diffusion mechanisms accompanying grain growth, neck growth and elimination of pores at above 900°-1000°C. For the powder which predominantly consisted of particles of above 1μm, the densification by the rearrangement was not observed and the densification proceeded slowly by diffusion mechanisms at above 1000°C. The high sinterability of fine TiO2 powder is considered to be due to (1) the densification by the rapid rearrangement and (2) the contribution of the effects of particle size on the sintering in the diffusion mechanisms.
