Grain Growth in Relaxor Ferroelectrics

Published

August 1, 2002

Author(s)

J Blendell, Jay S. Wallace

Abstract

The mechanisms controlling normal and exaggerated grain growth in lead magnesium niobate - lead titanate (PMN - PT) ceramics have been investigated by varying the PbO-based liquid phase volume fraction, the PT content and the MgO stoichiometry. There is a transition in matrix grain growth rate and matrix grain shape with liquid fraction. Samples with liquid fractions above 0.15 show significantly larger, facetted, cube-shaped grains, whose size was independent of liquid fraction, indicating that a surface nucleation rate mechanism controls growth in this regime. Exaggerated grains were found in the high liquid fraction samples. Orientation imaging microscopy showed that all of the exaggerated grains contained 60 twins but none of the normal matrix grains contained twins. Both the rate of grain growth and the nucleation of exaggerated grains were effected by the MgO stoichiometry. Excess MgO promoted the formation of exaggerated grains and increased the rate of grain growth for matrix grains. No exaggerated grain growth was observed in pure PMN.

Proceedings Title

Joint Contractors Meeting on Metallic Materials and Ceramic Materials (AFOSR)

Conference Dates

August 1, 2002

Conference Title

AFOSR Joint Contractors Meeting Report

Pub Type

Conferences

Keywords

exaggerated grain growth, grain growth, liquid phase sintering, microstructural development, PMN, relaxor ferroelectric

Citation

Blendell, J. and Wallace, J. (2002), Grain Growth in Relaxor Ferroelectrics, Joint Contractors Meeting on Metallic Materials and Ceramic Materials (AFOSR) (Accessed December 26, 2024)