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

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.

Keywords

References

  1. J. Mag Mater. v.19 Soft-Ferrite, Achievements and problems S. Krupicka
  2. Ceram Bull v.56 Development of Ferrites and Other Ferromagnetic Oxide Ceramics F.G. Brockman
  3. Mater. Sci. Eng. v.3 Magnetism, Microstructure and Crystal Chemistry of Spinel Ferrites A. Broese van Groenou;P.F. Bongers;A.L. Stuyls
  4. J. Am. Ceram Soc. v.70 no.6 Iron-Excess Manganese Ferrite: Electrical Conductivity and Cation Distributions H.-I. Yoo;H.L. Tuller
  5. Preparation and Characterization of Materials Developments in Preparation of Soft Ferrites B.K. Das;J.M. Honig(ed.);C.N.R. Rao(ed.)
  6. Proc. Sym. electroceramics and Solid-State Ionics, 172nd Meeting of the Electrochemical Society Grain Boundary and Electrode Impedance in Manganese Ferrites H.-I. Yoo;H.L. Tuller;J.A. Weirick;W.D. Kehr;H.L. Tuller(ed.);D.M. Smyth(ed.)
  7. J Electrochem. Soc. v.138 no.11 Electrochemical Investigation of the Oxygen Activity at the Maganosite-Hausmanite Equilibrium M. Keller;J. Xue;R. Dieckmann
  8. Introduction Defects and Diffusion in Solids S. Mrowec
  9. Ber Bunsenges. Phys. Chem. v.86 Defects and Cation Diffusion in Magnetite (Ⅳ): Nonstoichiometry and Point Defect Structure of Magnetite R. Dieckmann
  10. J Phys. Chem. Solids v.49 no.7 Analytic Calculation of Cation Ditributions in Ferrite Spinel Mn₁-$_rFe₂$+rO₄ H.-I. Yoo;H.L. Tuller
  11. Solid State Ionics v.62 Point Defects and Cation Tracer Diffusion in ($Co_λ$Fe₁-$_x$)₃-$_δO₄$ Spinels F.-H. Lu;S. Tinkler;R. Dieckmann
  12. Solid State Ionics v.53-56 Point Defects and Cation Tracer Diffusion in (Co, Fe, Mn)₃-$_δO₄$ Spinels: Ⅰ. Mixed Spinels ($Co_λ$$Fe_2y$$Mn_y$)₃-$_δO₄$ F.-H. Lu;R. Dieckmann
  13. Solid State Ionics v.59 Point Defects and Cation Tracer Diffusion in (Co, Fe, Mn)₃-$_δO₄$ Spinels:Ⅱ . Mixed Spinels ($Co_x$$Fe_z$$Mn_2z$)₃-$_δO₄$ F.-H. Lu;R. Dieckmann
  14. Modern Ferrite Technology A. Goldman
  15. Russ. J. Phys. Chem (Engl. Transl.) v.49 no.6 The Oxygen Pressure-Composition Diagram for the Magnesium-Iron-Oxygen System A.G. Zalazinskii;V.F. Balakirev;V.P. Barkhatov;G.I. Chufarov
  16. 박사학위논문 Mg-Fe-O계: 전기적 성질, 상평형, 화학확산 장세홍
  17. Ber Bunsenges. Phys. Chem. v.70 Fehlordnung in Ferriten H. Schmalzried;J.D. Tretyakow
  18. J Am. Ceram. Soc. v.67 no.1 Thermoelectric Determination of Cation Distributions in Fe₃O₄-MgFe₂O₄ A. Trestman-Matts;S.E. Dorris;T.O. Mason