Premium
Phase Relations in the Garnet Region of the System Y 2 O 3 –Fe 2 O 3 –FeO–Al 2 O 3
Author(s) -
HOOK H. J.
Publication year - 1963
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.1151-2916.1963.tb11693.x
Subject(s) - orthoferrite , liquidus , corundum , yttrium , isobaric process , spinel , crystallization , analytical chemistry (journal) , materials science , mineralogy , solid solution , kyanite , phase (matter) , oxide , hematite , melting point , yttrium iron garnet , thermodynamics , geology , chemistry , magnetization , metallurgy , quartz , physics , organic chemistry , chromatography , quantum mechanics , magnetic field , composite material
Liquidus equilibrium relations for the air isobaric section of the system Y 2 O 3 –Fe 2 O 3 –FeO–Al 2 O 3 are presented. A Complete solid‐solution series is found between yttrium iron garnet and yttrium aluminum garnet as well as extensive solid solutions in the spinel, hematite, orthoferrite, and corundum phases. Minimum melting temperatures are raised progressively with the addition of alumina from 1469°C in the system Y–Fe–O to a quaternary isobaric peritectic at 1547°C and composition Y 0.22 Fe 1.08 Al 0.70 O 2.83 * Liquidus temperatures increase rapidly with alumina substitutions beyond this point. The thermal stability of the garnet phase is increased with alumina substitution to the extent that above composition Y 0.75 Fe 0.65 Al 0.60 O 3 garnet melts directly to oxide liquid without the intrusion of the orthoferrite phase. Garnet solid solutions between Y 0.75 Fe 1.25 O 3 and Y 0.75 Fe 0.32‐ Al 0.93 O 3 can be crystallized from oxide liquids at minimum temperatures ranging from 1469° to 1547°C, respectively. During equilibrium crystallization of the garnet phase, large changes in composition occur through reaction with the liquid. Unless care is taken to minimize temperature fluctuations and unless growth proceeds very slowly, the crystals may show extensive compositional variation from core to exterior.