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Rare‐Earth‐Oxide‐Metal Eutectic Composites
Author(s) -
STENDERA J. W.,
BENZEL J. F.
Publication year - 1975
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.1151-2916.1975.tb19572.x
Subject(s) - sesquioxide , eutectic system , materials science , oxide , metal , impurity , composite material , fiber , morphology (biology) , aluminium oxides , rare earth , metallurgy , microstructure , chemistry , catalysis , organic chemistry , biology , genetics , biochemistry
Unidirectionally solidified composites of a rare‐earth sesquioxide + CeO 2 + (Mo or W) and of CeO 2 + (Mo or W) were grown using the direct‐rf‐coupling internal‐molten‐zone technique. The dramatic fiber improvement on addition of CeO 2 to the sesquioxide systems suggests that it provides extra loosely bound oxygen to increase the solubility of the metal in the molten oxide. The composites have extensive areas of ordered eutectic growth containing from 8 to 50 × 10 6 metal fibers/cm 2 ; the fibers are 0.1 to 0.6 μm in diameter. Fiber density increased almost linearly as the growth rate was increased from 0.5 to × 5.0 cm/h. Slow growth favors the platelet metal morphology over the fiber morphology. Platelets are typically observed in areas where high impurity concentrations would be expected, e.g. at the top of the solidified zone and at grain boundaries.