四方钨青铜结构NaSr_(2)Nb_(5)O_(15)铁电陶瓷的致密化

Densification of NaSr_(2)Nb_(5)O_(15) Ferroelectric Ceramics with Tetragonal Tungsten Bronze Structures

以TTB结构的NaSr_(2)Nb_(5)O_(15)(NSN)为研究对象,采用常规固相烧结法合成的NSN和中间体(NaNbO3和SrNb2O6)粉体作为基体,利用熔盐法合成大尺寸的NSN微晶作为晶种。通过原料设计,制备出致密的NSN陶瓷。研究了晶种含量对NSN陶瓷烧结行为和微观组织的影响。结果表明:在基体中加入晶种,通过反应烧结可以制备出致密的NSN陶瓷;随着晶种含量的增加,NSN陶瓷的微观组织结构发生明显变化。

Ceramics with tetragonal tungsten bronze(TTB)-type structures undoped with sintering aids are difficult to densify due to the high anisotropy of their crystal structures.In this paper,TTB-structured NaSr_(2)Nb_(5)O_(15)(NSN)was selected as the research object to prepare dense ceramics by the design of raw materials.Two powders synthesized by conventional solid-state sintering and molten salt methods were used.The former powder consisted of three phases as the matrix,NSN and intermediate phases(NaNbO3 and SrNb2O6).The latter powder,with a large particle size,acted as a seed.The effects of seed content on the sintering behavior and microstructure of NSN ceramics were investigated.Dense NSN ceramics were prepared by reaction sintering using seed addition into the matrix.The seed content had an obvious influence on the microstructures of the NSN ceramics.