Low-temperature sintering of submicronic randomly oriented Bi4Ti3O12 materials

Ultrafine powders of Bi4Ti3O12 With a narrow size distribution were prepared by the oxalate coprecipitation method. Compacts of the calcined powders were pressureless sintered at 850-1100 degrees C in air, and the densification process was studied by non-isothermal and dilatometric experiments. A rapid densification (similar to 98% of theoretical density) below 875 degrees C took place, which was attributed to both an uniform pore-size distribution in the green starting compact and a rearrangement of particles. The development of platelike grains, the platelike colony formation, and a rapid grain growth decreased densification above 900 degrees C. Microstructural development was studied and dielectric and electrical preliminary results are also given.