Journal of the Korean Ceramic Society (한국세라믹학회지)

The Korean Ceramic Society (한국세라믹학회)
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Determination of Nonstoichiometry$(\delta)$and Phase Stability Region of $(Mg_{0.29}Fe_{0.71})_{3-}\deltaO_4$ by a Coulometric Titration Method

전하적정법에 의한 $(Mg_{0.29}Fe_{0.71})_{3-}\deltaO_4$ 훼라이트의 Nonstoichiometry$(\delta)$와 상안정 영역 결정

  • 강선호 (서울대학교 무기재료공학과) ;
  • 유한일 (서울대학교 무기재료공학과) ;
  • 강대석 (국방과학기술연구소) ;
  • 유병두 (국방과학기술연구소)
  • Published : 1994.12.01
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Abstract

Nonstoichiometry($\delta$) and the phase stability region of a ferrite spinel (Mg0.29Fe0.71)3-$\delta$O4 have been investigated by a coulometric titration method as a function of temperature(T) and oxygen partial pressure(Po2). It has been found that the spinel is thermodynamically stable in the ranges -8.0$\leq$log(PO2/atm)$\leq$-2.4, -7.0$\leq$log(PO2/atm)$\leq$-1.7 respectvely at 100$0^{\circ}C$. The nonstoichiometry extends over the ranges of -0.004$\leq$$\delta$$\leq$0.007, -0.008$\leq$$\delta$$\leq$0.006, -0.033$\leq$$\delta$$\leq$0.004 at 100$0^{\circ}C$, 120$0^{\circ}C$, respectvely. The observed PO2-dependence of $\delta$ suggests that the majority ionic defects are cation interstitials in the low PO2 region and cation vacancies in the high PO2 region.

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References

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