Study by thermogravimetry, electrical conductivity and IR spectrometry of the phase transition for manganese cation deficient spinels

Autor:	Gillot, B., El Guendouzi, M., Laarj, M., Tailhades, P., Rousset, A.
Zdroj:	Journal of Materials Science; September 1988, Vol. 23 Issue: 9 p3342-3347, 6p
Abstrakt:	Thermogravimetry, electrical conductivity and IR spectrometry were used to study the crystal structure change of the metastable manganese cation deficient spinels that occur during the oxidation of manganese ions above 500° C. The kinetic of the transformation is found to be governed by a nucleation growth mechanism with an activation energy varying with the amount of Mn3+ ions. The nature of the inversion products depends on the manganese substitution extent. We observe for a substitution extent x<0.72 a phase with a corundum structure which is a solid solution of a-(MnFe)2O3 and for x>0.72 a mixture of two phases a-(MnFe)2O3 + Mn2O3 of orthorhombic structure.
Databáze:	Supplemental Index
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