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自Okazaki提出陶瓷晶粒的壳-芯(grain shell—grain core)设想后,先后被我们和 Rawal_xHennings等在 SrTIO_3和 PTC型 BaTiO_3上得到证实。研究结果表明,陶瓷晶粒的壳-芯结构实际是一种新型的铁电复合材料。它主要由掺杂原子的不均匀分布,形成铁电与非铁电相,或者具有不同介电性质的非均匀相。因此,由电镜揭示的壳-芯结构为材料科学中,探索新工艺,研制更优性能的陶瓷材料又提供了一个新的途径。然而,有关壳-芯结构的许多基本问题尚待进一步研究。本文在晶格、原子尺度研究了晶粒壳-芯结构的界面以及晶粒芯处畴界的微观结构特点。样品选用高纯、粒度小于0.μm的BaTiO_3为原料,同时添加一定量Nb_2O_5和C_0O以及助熔剂。采用通常的电子陶瓷工艺,制备出BaTiO_3多层电容器陶瓷。陶瓷性能与美国TAM公司X7R 162L
Since Okazaki proposed the concept of a grain shell-grain core of ceramic grains, it was successively confirmed by us and Rawal_xHennings on SrTIO_3 and PTC-type BaTiO_3. The results show that the shell-core structure of ceramic grains is actually a new ferroelectric composite material. It is mainly due to the heterogeneous distribution of doped atoms, the formation of ferroelectric and non-ferroelectric phases, or heterogeneous phases with different dielectric properties. Therefore, the shell-core structure revealed by the electron microscope provides a new way for material science to explore new technologies and develop better performance of ceramic materials. However, many basic questions about shell-and-core structure are yet to be further studied. In this paper, the microstructure characteristics of the grain-shell-core interface and the domain boundaries at the grain core are investigated at lattice and atomic scales. Samples using high purity, particle size less than 0. μ m BaTiO_3 as raw material, while adding a certain amount of Nb_2O_5 and C_0O and flux. BaTiO_3 multilayer capacitor ceramic was prepared by the usual electronic ceramic process. Ceramic performance and the United States TAM X7R 162L