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Nonuniformity of Potassium Ions in β ‐Alumina Ceramics
Author(s) -
YASUT ITARU,
DOREMUS R. H.
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.tb15545.x
Subject(s) - materials science , ceramic , potassium , grain boundary , sodium , potassium nitrate , ion , mineralogy , composite material , lithium nitrate , chemical engineering , metallurgy , microstructure , chemistry , organic chemistry , ionic bonding , engineering
A nonuniform distribution of K was found in β ‐alumina that had been in contact with sodium polysulfide or sodium nitrate melts containing small amounts of K. Large β ‐alumina grains in contact with the melt had approximately the equilibrium concentration of K expected from studies on single crystals of β ‐alumina, but surrounding grains contained little or no K. Thus the mobility of K ions in grain boundaries in β ‐alumina appears to be very low. Stresses from K concentration at the ceramic surface could enhance other incipient sources of failure such as seal stresses, cracks, and other defects.