GRAIN-BOUNDARY MIGRATION IN NONSTOICHIOMETRIC SOLID-SOLUTIONS OF MAGNESIUM ALUMINATE SPINEL .2. EFFECTS OF GRAIN-BOUNDARY NONSTOICHIOMETRY

被引：79

作者：

CHIANG, YM ^{[1
]}

KINGERY, WD ^{[1
]}

机构：

[1] MIT,DEPT MAT SCI & ENGN,CAMBRIDGE,MA 02139

来源：

JOURNAL OF THE AMERICAN CERAMIC SOCIETY | 1990年 / 73卷 / 05期

关键词：

aluminates; diffusion; grain boundaries; segregation; spinels;

D O I：

10.1111/j.1151-2916.1990.tb05172.x

中图分类号：

TQ174 [陶瓷工业]; TB3 [工程材料学];

学科分类号：

0805 ; 080502 ;

摘要：

The grain‐boundary chemistry of magnesium aluminate spinel solid solutions MgO·nAl2O3 in which grain growth measurements were reported in part I has been investigated in order to understand the mechanism of grain‐boundary migration. It is found that although segregation of impurity Ca and Si is common, much larger deviations in grain‐boundary stoichiometry are present. There is an excess of Al and O relative to Mg at grain boundaries in all compositions. Grain‐boundary migration appears to be rate‐limited by solute drag from intrinsic defects accommodating lattice nonstoichiometry, rather than by extrinsic solutes, consistent with the observed impurity tolerance of grain‐boundary mobility. Different rate‐limiting defects are proposed for magnesia‐rich and alumina‐rich spinels. Copyright © 1990, Wiley Blackwell. All rights reserved

引用

页码：1153 / 1158

页数：6

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[1] FOIL THICKNESS MEASUREMENTS FROM CONVERGENT-BEAM DIFFRACTION PATTERNS [J].