Journal of the Korean Ceramic Society (한국세라믹학회지)

The Korean Ceramic Society (한국세라믹학회)
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Characteristics of $TiO_2$ Powders Prepared by Freeze Drying Method

동결건조법으로 제조한 $TiO_2$의 특성

  • 윤기현 (연세대학교 요업공학과) ;
  • 박승순 (연세대학교 요업공학과)
  • Published : 1988.03.01
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Abstract

Extremely fine $TiO_2$ powders were synthesized from titanium chloride by the precipitation and freeze drying method. The phase transformation and electrical conductivity were investigated as a function of temperature. X-ray analysis showed that the phase transformation of the synthesized powder from the anatase to rutile occured at 64$0^{\circ}C$ and finished at 92$0^{\circ}C$ due to small particle size and large specific surface area. The activation energy obtained from electrical conductivity vs. temperature was about 1.63eV. This relatively large value was due to porosity in the specimen.

동결건조법에 의하여 $TiCl_4$로부터 아주 미세한 $TiO_2$ 분말을 합성하고, 상전이와 전기전도도를 논하였다. 동결건조법에 의하여 합성된 $TiO_2$ 분말의 anatase에서 rutile로의 상전이는 64$0^{\circ}C$에서 일어나 92$0^{\circ}C$에서 완전히 이루어졌다. 이러한 저온에서의 상전이는 미세한 분말과 비표면적에 기인한다. 전기전도도값으로 부터 얻은 활성화에너지값은 비교적 높은 1.63eV인데 이는 시편의 다공성 때문이다.

Keywords

References

  1. Phys. Rev. v.61 The Electrical Conductivity of Titanium Dioxide Marshall D. Earle
  2. Phys. Rev. v.87 Electrical and Optical Properties of Rutile Single Crystals D.C. Cronemeyer
  3. J. Electrochem. Soc. v.114 no.2 Studies of the Defect Structure of Nonstiochiometric Rutile, $TiO_{2-x}$ R.N. Blumenthal
  4. Ceram. Bull. v.54 no.3 TiO₂as an Air-to-Fuel Ratio Sensor for Automobile Exhausts T.Y. Tien(et al.)
  5. SAE Congr. Paper 790140 Titania Exhaust Gas Sensor for Automotive Applications M.J. Esper(et al.)
  6. Ceram. Eng. and Sci. Proc. 8th Automot. Mat. conf. v.1 Resistive-Type Exhaust Gas Sensors E.M. Logothetis
  7. J. Am. Ceram. Soc. v.42 no.3 Thermal Chemistry of Colloidal Titanium Dioxide W.F. Sullivan(et al.)
  8. J. Am. Ceram. Soc. v.44 no.3 Grain Growth and Phase Transformation of titanium Oxide During Calcination Yoshio Iida(et al.)
  9. Ultrastructure Processing of Ceramics, Glasses & Composites L.L. Hench(et al.)
  10. Yogyo-Kyokai-Shi v.90 no.6 Characterization and Sinterability of Mg-Al Spinel Powders Prepared with a Thermal Decomposition of a Freeze-dried Sulfate Z. Nakagawa(et al.)
  11. Elements of X-Ray Diffraction B.D. Cullity
  12. L'onde E'electrique v.335 Bases the Oriques de la Mesure de la Resistivit'e et de la Constante de Hall par la Me'thode des Pointes J. Laplume
  13. Titanium, its Occurrence, Chemistry and Technology T. Bardsdale
  14. J. Am. Ceram. Soc. v.48 no.8 Kinetics of the Anatase-Rutile Transformation R.D. Shannon(et al.)
  15. Introduction to Ceramics W.D. Kingery
  16. J. Exptl. Theoret. Phys. U.S.S.R. v.21 S.I.Gorelik
  17. J. Phys. Chem. Solids. v.V27 Electrical Conductivity of Nonstoichiometric Rutile Single Crystals from 1000℃ to 1500℃ R.N. Blumenthal(et al.)