LOW-TEMPERATURE SINTERING OF SUBMICRONIC RANDOMLY ORIENTED BI4TI3O12 MATERIALS

Ultrafine powders of Bi4Ti3O12 With a narrow size distribution were pr epared 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 dilatometr ic experiments. A rapid densification (similar to 98% of theoretical d ensity) below 875 degrees C took place, which was attributed to both a n uniform pore-size distribution in the green starting compact and a r earrangement of particles. The development of platelike grains, the pl atelike colony formation, and a rapid grain growth decreased densifica tion above 900 degrees C. Microstructural development was studied and dielectric and electrical preliminary results are also given.