Sintering Behaviour of Fine Barium Titanate (BaTiO3) Powders Consolidated with the Pressure Filtration Method

摘要

Main aim of the study was the determination of the sintering behaviour of fine barium titanate powders consolidated with the pressure filtration method. Three commercial powders with primary particle size of 50, 100 and 200 nm were used. Relationships between particle size, characteristics of the consolidated bodies and their sintering behaviour were investigated. The far-reaching goal of the study was the production of transparent or translucent barium titanate, a material that is part of a group of transparent ferroelectric ceramics applied in electro-optical devices. Aqueous and propanol suspensions of the powders were prepared and pressure-filtered at 10 MPa. Materials consolidated from the aqueous suspensions showed more advantageous pore size distributions, i.e. smaller modal pore diameter and lower total pore volume than those formed from the propanol suspensions and materials formed by means of cold isostatic pressing of the powders at 120 MPa. This was attributed to the smaller size of particles present in the aqueous suspensions compared with those in the propanol suspensions. Onset of the sintering process observed in dilatometric measurements was at 900-950 degrees C. The highest densities of approx. 98 % were achieved with sintering at 1300 degrees C or 1350 degrees C in air. Density exceeding 99 % was achieved by sintering with the SPS method at 1100 degrees C. Transmittance of the sample reached 55 % in the near-IR region.