金属アルコキシド法によるNb₂O₅-コーティングBaTiO₃複合粒子の合成と評価

抄録

Chemical processing of Nb₂O₅-added BaTiO₃ composites was investigated with the surface modification through the hydrolysis of niobium alkoxide on the surface of BaTiO₃ particles.
BaTiO₃ particles were coated with niobium hydroxide particles formed by preferential hydrolysis of niobium pentaethoxide on the surfaces of BaTiO₃ particles, which can lead to the preparation of highly homogeneous composite particles of Nb₂O₅BaTiO₃.
It was clarified from the BET measurement, the SEM&TEM observation and Zeta-potential measurment that original BaTi0₃ particles were homogeneously coated with niobium hydroxide particles.
Iwt%Nb₂O₅-added BaTiO₃ bodies sintered at 1250-1300°C exhibited a flattened dielectric temperature dependence (dielectric constants of 2200 to 2400) with lower loss(tan δ<1.0%) in the temperature range of -30 to 80°C, indicating a relaxor characteristics. The microstructure of Nb₂O₅-added BaTiO₃ sintered bodies consisted of grains of several μ m which are much smaller than ones of non-added BaTiO₃ sintered bodies, suggesting that the grain growth of BaTiO₃ was inhibited by niobium existing at the grain boundaries.