Crescimento de grãos anômalos em titanato de bário. / Abnormal grain growth in barium titanate.

AUTOR(ES)

Haroldo Lhou Hasegawa

DATA DE PUBLICAÇÃO

2004

RESUMO

Barium Titanate (BaTiO3) and derived material are extensively used in the manufacture for a large range of electronic components like multilayer ceramic capacitors (MLCC), semi-conductor devices, PTCR (positive temperature coefficient resistor) and electro-optic devices. Advanced ceramic powders preparation is playing an important role in modern ceramic research. Solid state synthesis of barium titanate has been studied in turning of the physical and chemical characteristics of the raw materials with special attention to the impurity levels, particle size distribution and particle morphology. Barium titanate has been in use for more than fifty years but important of the microstructure development is still needed for electronic ceramics in the future. The present work investigates the microstructural changes, mainly abnormal grain growth during the sintering of undoped and doped BaTiO3, with yttrium and barium. Samples doped with at least 0.15% mol of yttrium presented abnormal grain in a size around 50 m and samples doped with at least 0.15% mol of barium presented abnormal grain in a size around 25 m. Such fact can be attributed to the presence of localized liquid phase, during the sintering, leading to formed dissolution (or precipitation) sites and resulting in abnormal grain growth.

ASSUNTO(S)

material cerâmico: titanato de bário engenharia de materiais e metalurgica perovskita defeitos iônicos crescimento de grão

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