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Grain‐Boundary Migration in Nonstoichiometric Solid Solutions of Magnesium Aluminate Spinel: I, Grain Growth Studies
Author(s) -
Chiang YetMing,
Kingery W. David
Publication year - 1989
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1989.tb06113.x
Subject(s) - spinel , grain boundary , materials science , magnesium , grain growth , aluminate , impurity , stoichiometry , atmospheric temperature range , mineralogy , metallurgy , ionic bonding , analytical chemistry (journal) , grain size , crystallography , inorganic chemistry , chemistry , thermodynamics , microstructure , ion , chromatography , physics , organic chemistry , cement
The grain‐boundary mobility in magnesium aluminate spinel (MgO · nAl 2 O 3 ) of magnesia‐rich ( n < 1) and alumina‐rich ( n > 1) compositions has been measured from normal grain growth in dense, hot‐pressed samples. Over the temperature range 1200° to 1800°C, the mobility in magnesia‐rich compositions is found to be greater than that in alumina‐rich compositions by a factor of 10 2 to 10 3 . Within the alumina‐rich field, the mobility varies by less than a factor of 10 over the composition range 1 > n > 1.56. Nearly stoichiometric spinels (1 < n < 1.07) form a variety of sources and starting materials exhibit boundary mobilities within a factor of 5 at fixed temperature, showing an impurity tolerance which has not been found in other ionic solids.