The Korean Journal of Ceramics

The Korean Ceramic Society (한국세라믹학회)
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A Study on the Defect Structure of $TiO_2$ (Rutile) by Electrical Conductivity Measurements

  • Son, Jae-Cheon (The Institute of Industrial Technology, Korea University) ;
  • Yu, In-Kyu (Hyundai Electronics Co., Icheon)
  • Published : 1996.09.01
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Abstract

The electrical conductivity of polycrystalline TiO2 samples was measured over the temperature range 1000°-1400℃ and from 0.21 to 10-16 atm of oxygen. Based on the excellent fit observed between the theoretically derived relatin σ3=(Aσ+B)Po2-1/2+D'σ2 and the experimental conductivity data, the nonstoichimetric defect structure of TiO2 was rationalized in terms of a defect model involving quasi-free electrons and both singly and doubly ionized oxygen vacancies. The standard enthalpy of formation for the following defect reactions in TiO2. (a) OO={{{{ { 1} over {2 } }}O2(g)+VO+e'; Δ{{{{ { H}`_{o } ^{a } }}=5.15(eV) (b) OO={{{{ { 1} over {2 } }}O2(g)+VO+2e'; Δ{{{{ { H}`_{0 } ^{ a} }}=6.30(eV) (c) VO=VO+e'; Δ{{{{ { H}`_{0 } ^{a } }}=1.15(eV) were determined from the temperature dependence of A and B obtained from the above relation and from the experimental expression between the electron mobility and temperature. The electrical conductivity of TiO2 in air below approximately 950℃ appears, on the basis of this investigation, to be impurity controlled due to the presence of aluminum rather than intrinsic conduction.

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References

  1. J. Electrochem. Soc. v.114 Studies of the Defect Structure of Nonstoichiometric Rutile, $TiO_{2-x}$ R. N. Blumenthal;J. Baukus;W. M. Hirthe
  2. J. Les-Common Metals v.22 The Determination of Oxyten Partial Pressure Dependence of x in $TiO_{2-x}$ J. S. Anderson;A. S. Khan
  3. J. Phys. Chem. Solids v.23 Thermogravimetric Studies of the Defect Structure of Rutile P. Kofstad
  4. Acta Chem. Scand v.18 The Defect Structure of Rutile K. S. Fφrland
  5. J. Am. Ceram. Soc. v.48 A Study on the Nonstoichiometry of $TiO_2$ J. B. Moser;R. N. Blumenthal;D. H. Whitmore
  6. J. Am. Ceram. Soc. v.48 On the Defect Structure of Rutile L. M. Atlas;G. J. Schlehman
  7. Proc. Br. Ceram. Soc. v.8 Dependence of $TiO_2$ on the Oxygen Partial Pressure C. B. Alcock;S. Zador;B. C. H. Steele
  8. J. Less-Common Metals v.13 Nonstoichiometry of $TiO_2$ P. Kofstad
  9. J. Phys. Chem. Solids v.27 Electrical Conductivity of Nonstoichiometric Rutile Single Crystals from 1000℃ to 1500℃ R. N. Blumenthal;J. Coburn;J. Baukus;W. M. Hirthe
  10. Solid St. Commun. v.1 Experimental Evidence from Conductivity Measurements for Interstitial Titanium in Reduced $TiO_2$ D. S. Tannhauser
  11. J. Am. Chem. Soc. v.67 Interstitial Titanium Defect Model of $TiO_2$ from the Defect Reaction L. S. Darken;R. W. Gurry
  12. J. Appl. Phys. v.32 Recent Studies on Rutile($TiO_2$) H. R. P. Frederikse
  13. Phys. Rew. v.130 Dependence of the Electrical Conductivity and Thermoelectric Power of Pure and Aluminum-Doped Rutile on Equilibrium Oxygen Pressure and Temperature J. Yahia
  14. Phys. Rev. v.87 Electrical Conductivity of Al-doed $TiO_2$ D. C. Cronemeyer