Phase Equilibria of the Ferrous Ferrite System of <TEX>$(Mg_{0.29}-yMnyFe_{0.71})_{3-}delta$O_4$</TEX>

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J. Korean Ceram. Soc. > Volume 32(3); 1995 > Article

Journal of the Korean Ceramic Society 1995;32(3): 394.

$(Mg_{0.29}-yMnyFe_{0.71})_{3-}delta$O_4$ 훼라이트계의 상평형

채정훈, 유한일, 강선호, 강대석¹, 유병두¹

서울대학교 신소재 공동연구소
¹국방과학기술연구소

Phase Equilibria of the Ferrous Ferrite System of $(Mg_{0.29}-yMnyFe_{0.71})_{3-}delta$O_4$

ABSTRACT

Electrical conductivity and thermoelectric power of the ferrous ferrite system of (Mg0.29-yMnyFe0.71)3-$delta$O4 have been measured as function of the thermodynamic variables, cationic composition(y), temperature(T) and oxygen partial pressure(Po2) under thermodynamic equilibrium conditions at elevated temperatures. On the basis of the electrical properties-phase stability correlation, the stability regions of the ferrite spinel and its neighboring phases have been subsequently located in the log Po2 vs. y and log Po2 vs. 1/T planes in the ranges of 0 y 0.29, 1100 T/$^{circ}C$ 1400 and 10-14 Po2/atm 1. The stability region, Δlog Po2(y, 1/T), of the ferrite spinel single phase widens with increasing Mn-content(y) and the boundaries of each region are linear against 1/T with negative slopes.

Key words: Mg-Mn ferrite, Electrical conductivity, Thermoelectric power, Stability region