ABNORMAL GRAIN-GROWTH OF NIOBIUM-DOPED STRONTIUM-TITANATE CERAMICS

We have investigated the influence of the Ti/Sr ratio and particle siz e on abnormal grain growth of Nb-doped SrTiO3 ceramics, As the Ti/Sr r atio increases, the onset time and temperature of abnormal growth incr ease, for specimens sintered at temperatures above 1440 degrees C. Whe n the particle size is decreased by milling, the onset and completion temperatures of the abnormal growth and the final grain size are decre ased. The abnormal grains growing during isothermal heating are nearly tetrakaidecahedral in shape, whereas those growing during rising temp erature have the morphology of an edge-cut cube.