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Oxygen‐Pressure Dependence of Cation Interdiffusivity in Magnesiowustite Solid Solutions
Author(s) -
SATA N.,
GOTO K. S.
Publication year - 1982
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.1151-2916.1982.tb10386.x
Subject(s) - oxygen , solid solution , mole fraction , oxygen pressure , diffusion , chemistry , analytical chemistry (journal) , ternary operation , thermodynamics , phase diagram , phase (matter) , physics , organic chemistry , computer science , programming language
Cation interdiffusivity in magnesiowustite solid solutions was measured as a function of temperature and oxygen pressure. During diffusion, the local composition of Fe 2+ and Fe 3+ was always equal to the equilibrium composition with the oxygen pressure in the. gas phase. The interdiffusivity is empirically expressed as D=DP 0 P 0 2 1/n expβX Fe . The interdiffusivity increases exponentially with iron mole fraction between 30 and 80 mol% Fe at a given oxygen pressure and temperature. The value of β was between 8 and 10 with the 1/n value 1/2 to 1/5 at 1250° to 1350°C. This oxygen‐pressure dependence of the interdiffusivity is equal to that of the product of defect concentration (Roth‐type cluster) and correlation factor. From the result, iso‐interdiffusivity lines are drawn in the broad range of the magnesiowustite solid solution in the MgO‐FeO‐Fe 2 / 3 O quasi‐ternary system.