Centrifugation and Fast Firing of a Commercial BaTiO3Powder

Commercial BaTiO3.powder of approximately lpm average particle size was subjected to three independent treatments to reduce fired grain size: fast firing, centrifugal classification, and doping. The 1370°C conventional firing produced 90+w grains in both undoped samples. In the doped sample conventional firing produced 7.0pm grains. Fast firing (1450°C) produced 20pm (undoped, not centrifuged), 13um (undoped, centrifuged), and 3pm (doped, not centrifuged) grain sizes at approximately 98% theoretical density. Measurements of grain size and porosity of samples removed at intervals during firing confirm these trends. Therefore it is found that all three variables reduce grain growth. centrifugation was reduced by the small number of particles in the 0.6-0.7 m range which would tend to grow at the expense of the rest of the particles. A narrower centrifuged "cut" would lead to less chance of grain growth but a submicron fired grain size in an undoped powder appears unlikely without at least small dopant additions. The effect of