RELATIONSHIP BETWEEN MICROSTRUCTURE AND PROPERTIES OF SEMI-CONDUCTINGBARIUM-TITANATE PREPARED BY A SEMI-ALKOXIDE ROUTE

Yttria-doped barium titanate was successfully prepared by use of a sem i-alkoxide method using barium carbonate instead of barium acetate. Th e microstructure and the positive temperature coefficient of resistivi ty (PTCR) of sintered samples were analyzed using scanning electron mi croscopy and an impedance analyzer. It was found that the samples prep ared in this study showed very different microstructures and PTCR effe cts as a function of the Ba/Ti ratio than from those of samples prepar ed by the mixed oxide method. This difference is discussed in terms of chemical homogeneity, local compositional fluctuation and liquid phas e formation. (C) 1998 Elsevier Science B.V.