BaTiO_3-Ni複合セラミックスの焼結と誘電特性

概要

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BaTiO_3-Ni mixed powders were sintered at 1300℃ in Ar or air, and the sintering behavior and dielectric properties were investigated. The bulk density of sintered bodies was 95-99% of theoretical. BaTiO_3-Ni composites were produced in Ar. When coarse Ni powder (4-7 μm) and ultrafine BaTiO_3 powder (0.02 μm) were used, a large number of Ni particles were isolatedly dispersed in the BaTiO_3 matrix. The dielectric constant increased remarkably with an increase in Ni content up to ε_r'=11000 at 40 vol% Ni according to the modified Maxwell formula. Although monolithic BaTiO_3 sintered in Ar had a high dielectric loss owing to the formation of oxygen vacancies working as electron donor, BaTiO_3-Ni composite had a low dielectric loss. This is because of the fact that a small amount of NiO dissolved into BaTiO_3 and Ni ions worked as electron acceptor to compensate the charge of oxygen vacancies. Firing in air resulted in the oxidation of Ni to form BaTiO_3-NiO composites with low dielectric constants and high dielectric losses.
社団法人日本セラミックス協会の論文
1992-04-01