FAST-SINTERING OF HYDROTHERMALLY SYNTHESIZED BATIO3 POWDERS AND THEIRDIELECTRIC-PROPERTIES

Hydrothermally synthesized barium titanate (BaTiO3) powders with a sub micrometre particle size have been fast-sintered with a heating rate o f similar to 200 degrees C min(-1) at various temperatures (1250-1350 degrees C) for short times (5 and 15 min). The microstructures and die lectric properties of the sintered samples are studied and compared wi th those sintered conventionally. The sample fast-sintered at 1250 deg rees C for 5 min had the highest dielectric constant value of approxim ately 3700 with an average grain size of about 1 mu m. Both the dielec tric constant and the Curie-Weiss temperature are found to be dependen t on the grain size of the sintered samples, particularly when the ave rage grain size is less than 5 mu m. This has been attributed to the p resence of internal stress in the fine-grained BaTiO3.