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Equilibrium Studies of the System′(Fe,Co)O′–(Fe,Co) 3 O 4 by Solid‐State emf Measurements in the Temperature Range 970 to 1370 K
Author(s) -
Lundberg Mats,
Rosén Erik
Publication year - 1992
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.1151-2916.1992.tb04209.x
Subject(s) - analytical chemistry (journal) , electron microprobe , atmospheric temperature range , wüstite , galvanic cell , microprobe , chemistry , cubic zirconia , solid solution , electrolyte , solid state , oxygen , phase (matter) , thermodynamic equilibrium , materials science , mineralogy , thermodynamics , electrode , ceramic , physics , hematite , organic chemistry , chromatography
The equilibrium reaction 3‘(Fe, Co)O’( ss ) +1/2O 2 ( g ) ⇄ (Fe, Co) 3 O 4 ( ss ) was studied in the temperature range 970 to 1370 K for seven different total compositions of molar ratios 0.5 < Fe/(Fe + Co) ≤ 1.0. The equilibrium pressures of oxygen were determined by using galvanic cells incorporating calcia stabilized zirconia as solid electrolyte and the Fe/Co ratios in the solid‐solution phases by wavelength dispersive spectrometry microprobe analyses. The activities of ‘FeO’ in the cobaltowüstite phase were then derived from the experimental results obtained.