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Phase Equilibria in the Ferrite Region of the System FeO‐MgO‐Fe 2 O 3
Author(s) -
PALADINO A. E.
Publication year - 1960
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.1151-2916.1960.tb12979.x
Subject(s) - spinel , ferrite (magnet) , stoichiometry , lattice constant , oxygen , magnesium , phase (matter) , analytical chemistry (journal) , lattice (music) , atmospheric temperature range , materials science , chemistry , mineralogy , thermodynamics , metallurgy , diffraction , physics , organic chemistry , chromatography , acoustics , optics , composite material
Phase equilibria in the ferrite region of the system FeO–MgO–Fe 2 O 3 have been investigated up to 1300°C. over an oxygen‐pressure range of 1.0 to 0.01 atmospheres. The five most important features of the equilibria in this system are as follows: (1) The spinel phase can exist with a deficiency of oxygen in the high‐magnesium compositions, (2) Mg++ replaces Fe ++ in Fe 3 O 4 beyond the “stoichiometric MgFe 2 O 4 ,” corresponding to the formula (MgO) x MgFe 2 O 4 , where x = 0.092 ± 0.004 and is independent of temperature, (3) the spinel field does not include single‐phase composition corresponding to Mg‐Fe 2 O 4 , (4) the lattice constant of spinels in this system depends on cation distribution, and the extent of distribution changes as a function of temperature in turn depends on the magnesium concentration in the spinel, and (5) the spinel field near its terminus has little or no width.