Microstructures and Properties of BaTiO3-Ni Composite Dielectrics.

Abstract

BaTiO3-Ni mixed powders were sintered at 1300°C in Ar and the microstructures and electric properties of sintered bodies were investigated with emphasis on the effects of particle size of starting powders. Ni particles dispersed better in BaTiO3 matrix in BaTiO3(0.02μm)-Ni(4-7μm) system, in which the electric resistance was kept high at a large Ni content and the dielec-tric constant increased remarkably with increasing Ni content. On the other hand, Ni particles coalesced in BaTiO3(0.1μm)-Ni(4-7μm) systems at a small Ni content, resulting in a decrease in electric resistance. The significant growth of Ni particles was observed in BaTiO3(0.02μm)-Ni(0.02μm) system. It is concluded that the combination of coarse Ni and ultrafine BaTiO3 particles is effective to produce the dielectric composites, because Ni particles are coated with finer BaTiO3 powder on the mixing process.