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Observation of Potassium β m ‐Alumina in Sintered Alumina
Author(s) -
BLANC MICHEL,
MOCELLIN ALAIN,
STRUDEL J. L.
Publication year - 1977
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.1151-2916.1977.tb15522.x
Subject(s) - spinel , potassium , materials science , magnesium , intergranular corrosion , transmission electron microscopy , mineralogy , solubility , aluminium , oxide , metallurgy , inorganic chemistry , chemistry , microstructure , nanotechnology , organic chemistry
Potassium‐containing plate‐like precipitates having the β m ‐alumina structure were identified within intergranular spinel inclusions in MgO‐doped sintered aluminum oxide ceramics. Transmission electron microscopy revealed the corresponding epitaxial relation: (0001) β m {111} spinel and 1120 β m 110 spinel. Chemical analyses and quantitative metallography suggested that in α‐Al 2 O 3 the 1800 ° C solubility limits of magnesium and potassium do not exceed 300 to 400 ppm and 5 to 10 ppm by weight, respectively.