A位非化学计量对BiNbO_4陶瓷性能的影响

Effect of Non-stoichiometric Bi on Properties of BiNbO_4 Ceramics

为了研究烧成过程中可能的Bi挥发对BiNbO4系材料造成的影响,对A位非化学计量的Bi(1+x)NbO4材料烧结性能、晶相结构、显微织构及微波介电性能作了详细研究,结果表明,A位Bi少量缺量可以促进BiNbO4陶瓷晶粒的生长,使其烧结温度降低,烧结样品的晶相组成仍为正交-BiNbO4相,微波介电性能有所改善;A位Bi过量对BiNbO4陶瓷的烧结性没有明显影响,Bi过量达0.030时,烧结样品内有富Bi的Bi5Nb3O15第二相产生,样品的微波介电性能急剧恶化。

In order to clarify the influence of Bi evaporation, which might be caused in the sintering process, on the properties of BiNbO4 ceramics, the sintering behavior, crystal structure, microstructure, and microwave dielectric properties of non-stoichiometric Bi(1+x)NbO4 ceramics are investigated. The results show that the presence of small amount of A-site vacancy promotes the grain growth of BiNbO4 and reduces the sintering temperatures of BiNbO4 ceramics. The crystal phase of sintered samples is pure orthorhombic -BiNbO4 and the microwave dielectric properties are improved slightly. The sinterability of Bi-enriched Bi(1+x)NbO4 ceramics is not apparently changed compared with that of BiNbO4 samples. There is the second phase, Bi5Nb3O15 phase, appeared in sintered samples and the microwave dielectric properties critically deteriorated for Bi(1+x)NbO4 ceramics with x = 0.030.