钛酸钡粉体的表面包覆与电子陶瓷改性

为实现改性杂质与钛酸钡粉体的均匀混合，达到对材料微结构、相结构和电学特性的准确控制，对水热纳米晶钛酸钡粉体进行了改性杂质的非均匀形核表面淀积包覆．文中利用包覆Y（OH），后的钛酸钡粉体在水中的毛细管浸润性得到改善、以及两种工艺方法制备的粉体在液一固分离离心过程中离心转速对液一固分离率的影响，判断Y（OH），对钛酸钡粉体的包覆效果；探讨了掺杂工艺对Y掺杂钛酸钡陶瓷半导化和室温电阻率的影响，以及用非均匀形核表面淀积包覆工艺制备的陶瓷PTCR和细晶介质陶瓷的性质．润湿性实验显示，利用表面淀积包覆工艺确实能获得良好的包覆效果．

Surface Coating of BaTiO3 Powders and Modification of BaTiO3 -Based Electro-Ceramics

For the homogeneous mixing of BaTiO_3(BT) powders with dopants and the exact control of the microstructures,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 powders 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.