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Microstructure of (Fe 0.2 Co 0.8 ) 0.8 (Fe 2.38 Co 0.62 O 4 ): A Magnetic Oxidation Resistant Composite Formed by Coprecipitation
Author(s) -
YamegniNoubeyo JeanCelestin,
Pourroy Genevieve,
Werckmann Jacques,
Malatsi Riera Antoni,
Ehret Gabrielle,
Poix Paul
Publication year - 1996
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.1151-2916.1996.tb08933.x
Subject(s) - spinel , coprecipitation , materials science , microstructure , annealing (glass) , amorphous solid , ferrite (magnet) , cobalt , metal , transmission electron microscopy , composite number , alloy , high resolution transmission electron microscopy , chemical engineering , crystallography , mineralogy , metallurgy , composite material , chemistry , nanotechnology , engineering
The metal–ferrite composite (Fe 0.2 Co 0.8 ) 0.8 (Fe 2.38 Co 0.62 O 4 ) has been studied by X‐ray diffractometry measurements and high‐resolution transmission electron microscopy. Spinel ferrite occurs in highly crystalline domains 100–150 nm in size, and the iron–cobalt alloy occurs in smaller and less‐crystalline domains (10–20 nm). Both phases are heterogeneous in composition. The metal is embedded in the spinel phase, located near the edges, and overlaid by a poorly crystallized layer or misshapen regions containing small spinel crystals and amorphous phases. By annealing under vacuum up to 800°C, the misshapen regions disappear and the size of the metallic regions increases. The concentration of iron in the metallic regions decreases and their structure changes to face‐centered cubic, while the spinel becomes enriched in iron.