Electron Microscopy of Barium Bismuth Titanate Multilayer Ceramics
For a number of years bismuth containing compounds have been used with pre-calcined barium titanate to reduce the sintering temperature of the capacitor formulations. As reported earlier1, 2 the backscattered electron (BSE) SEM micrographs of the bismuth containing barium titanate ceramic reveal that the grains having an average size of 1.2 μm consist of a two phase structure consisting of relatively pure barium titanate grain cores surrounded by bismuth rich grain shells2 The TEM and STEM studies along with the EDS analyses show that the bismuth concentration increases sharply as one steps towards the grain boundary with a maximum bismuth content at the grain boundary. It is the purpose of this work to investigate the distribution of bismuth in these formulations including the bismuth content, if any, at the ceramic metal interface as affected by the sintering temperature. The subsequent effect on the electrical resistivity of these ceramics in the multilayer configuration is reported.
KeywordsElectrical Resistivity Barium Titanate Secondary Electron Image Bismuth Titanate Stem Analysis
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