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Microstructure and Grain Boundary Structure of Na + ‐Diffused (Sr,Ca)TiO 3 Capacitor‐Varistor Ceramics
Author(s) -
Zou Qing,
Meng Zhongyan
Publication year - 1995
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1995.tb08360.x
Subject(s) - grain boundary , materials science , microstructure , intergranular corrosion , amorphous solid , perovskite (structure) , grain boundary diffusion coefficient , ceramic , varistor , mineralogy , crystallography , composite material , chemistry , electrical engineering , voltage , engineering
The microstructure of (Sr,Ca)TiO 3 capacitor‐varistor materials has been investigated by employing electron microscopy techniques (TEM, STEM, HREM, EDX, and EPA). The material is found to contain (Sr,Ca)TiO 3 grains (∼30 μm) having perovskite crystal structure with domains, a Na + ‐diffused layer at the grain boundaries which is dependent on thermal diffusion conditions, and multiple‐grain junctions in which the Ti n O 2n–1 Magneli phase coexists with an amorphous intergranular phase. In addition, wider grain boundaries (10–30 nm), thin grain boundaries (∼1 nm), and clean grain boundaries which are free from intergranular phase were observed, and the effects of different grain boundaries on the diffusion of Na + are discussed.