Abnormal Grain Growth in Barium Titanate Doped with Alumina.

Authors :: Fisher, John G.
Si-Young Choi
Kang, Suk-Joong L.
Source :: Journal of the American Ceramic Society; Jul2006, Vol. 89 Issue 7, p2206-2212, 7p, 2 Color Photographs, 2 Black and White Photographs, 1 Chart, 2 Graphs
Publication Year :: 2006
Abstract: The effect of additions of ≤1 mol% Al<subscript>2</subscript>O<subscript>3</subscript> on abnormal grain growth in BaTiO<subscript>3</subscript> sintered for periods of ≤60 min at 1350°C has been studied. Addition of ≤0.2 mol% Al<subscript>2</subscript>O<subscript>3</subscript> caused an increase in the nucleation and growth rates of abnormal grains, with further additions causing a decrease. This behavior is explained by interface-controlled growth. Dopant adsorption reduces both the edge free energy and the step velocity of a grain, causing the nucleation and growth rates of abnormal grains to increase, pass through a maximum, and then decrease with increasing dopant concentration. [ABSTRACT FROM AUTHOR]