关键词: 钛酸钡, 粉体, 表面包覆, 电子陶瓷, 非均匀形核, 毛细管浸润性, 半导体, 电介质

Abstract:

For the homogeneous mixing of BaTiO₃(BT) powders with dopants and the exact control of the micro-structures,phases and electrical properties of materials,a heterogeneous nucleation method was used to coat dopant Y(OH)₃ on the surface of nano—crystallized hydrothermal BT powders. The coating effect of Y(OH)₃ on the pow-ders prepared by two methods was revealed according to the capillary wettability improvement of the coated powders in water and to the effect of the rotating speed on the eccentricity in separating the BT powders from the slurry using a centrifuge. And the influence of doping method on the semiconductivity and room—temperature resistance of the Y-doped BT ceramics was investigated. The properties of the BT-based PTCR ceramics and the dielectric ceramics with fine grain prepared by heterogeneous nucleation method were discussed also. It is demonstrated from the expe-rimental results of capillary wettability that Y(OH)₃ can be nicely coated on BT powders via the surface coating.

Key words: barium titanate, powder, surface coating, electro-ceramic, heterogeneous nucleation, capillary wetta-bility, semiconductor, dielectric