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Phase Transformations of Baddeleyite induced by Compression

Research Project

Project/Area Number 61460057
Research Category

Grant-in-Aid for General Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field 鉱物学(含岩石・鉱床学)
Research InstitutionOsaka University

Principal Investigator

KUME Shoichi  Professor,College of General Education, 教養部, 教授 (00029604)

Co-Investigator(Kenkyū-buntansha) TAKUBO Hiroshi  Associate Professor,College of General Education, 教養部, 助教授 (80029678)
Project Period (FY) 1986 – 1987
Project Status Completed (Fiscal Year 1987)
Budget Amount *help
¥4,300,000 (Direct Cost: ¥4,300,000)
Fiscal Year 1987: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1986: ¥3,600,000 (Direct Cost: ¥3,600,000)
Keywordsバデレアイト / 斜方晶ジルコニア / 相転移 / 高圧多形 / リートベルド法 / マルテンサイト転移 / 加圧相転移
Research Abstract

Baddeleyite.whose composition is denoted as ZrO_2.is found in rocks of pyroxenite or syenite.Its crystal symmetry is classified as monoclinic.No other allotropy has been known in nature.This material has two high temperature and two high pressure polymorphs. tetragonal and cubic.and Ortho(I)and(II)respectively.This substance.known under the name zirconia.possesses practically useful properties such as high strength and fracture toughness.These are strongly depend on the interrelations among the phases mentioned above.To promote these peculiarities.impurity-doped substances.which are stabilized to be one of high temperature forms.are now popular in technological applications.In this project.the stability fields of high pressure phases and a mechanism of phase transformation generated by compression have been investigated.
As for Ortho(I)phase.its existence had not been clear since its structure was difficult to be maintained at 1 atm.The present experiment succeeded to quench this phase … More when fine starting powder of ZrO_2 was prepared.In the similar processing.Ortho (I)phase of 2 mol%Y_2O_3 doped ZrO_2 was also quencheable but the tetragonal phase.which had originally coexisted in the starting powder.was always found in the product.This is explained by considering a fact that the stability of Ortho(I)and the tetragonal phases against compression is almost same and the latter survives after the removal of pressure since the difference in density between these two phases is small.The crystal structure of quenched Ortho(I)phase was refined by the Rietveld analysis.being confirmed to be the same as that determined under pressure.
Ortho(II)phases of both ZrO_2and 2 mo1%Y_2O_3were synthesized under conditions above 1000゜C and 10GPa.The Rietveld analysis of the product showed that it is isostructural with cotunnite.A peculiar phenomena were found in the case of Y_2O_3-doped sample depressed from pressures slightly below 10GPa.The product only consisted of the monoclinic phase but neither Ortho(I)nor the tetragonal was observed.This is probably due to a mechanism in which the tetragonal phase becomes unstable by compression close to 10GPa and turns to Ortho(I).As is already seen.Ortho(I)phase is unstable on decreasing pressure and the only monoclinic phase is found in the treated samples. Less

Report

(2 results)
  • 1987 Final Research Report Summary
  • 1986 Annual Research Report
  • Research Products

    (13 results)

All Other

All Publications (13 results)

  • [Publications] K. Furuno: Jap. J. Ap. Phys.25. 646-647 (1986)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] R. Suyama: Yogyo Kyokai Shi. 95. 567-568 (1987)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] 笹崎 謙一: 粉体および粉末冶金. 34. 22-26 (1987)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] H. Toraya: Mineral. J.13. 500-504 (1987)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] O. Ohtaka: J. Am. Ceram. Soc.(1988)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] O. Ohtaka: J. Am. Ceram. Soc.(1988)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] K.Furuno: "Sapphire-Anvil Cell for High Pressure Research" Jap.J.Ap.Phys.25. 646-647 (1986)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] R.Suyama: "Structural Refinements of ZrO_2 and HfO_2 treated at 600゜C.6 GPa" Yogyo Kyokai Shi. 95. 567-568 (1987)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] K.Sasazaki: "Examination of CIP Treatment Conditions for the Sintering of Y-TZP" J.Jap.Soc.Powder Powder Metal.34. 22-26 (1987)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] H.Toraya: "Unit cell parameters and densities of non-doped and 2 mo1%Y_2O_3 doped orthorhombic ZrO_2" Mineral.J.13. 500-504 (1987)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] O.Ohtaka: "Synthesis of the Orthorhombic Phase of 2Y-ZrO_2" J.Am.Ceram.Soc.(1988)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] R.Suyama: Journal of Ceramic Society of Japan. 95. (1987)

    • Related Report
      1986 Annual Research Report
  • [Publications] R.Suyama: Proceedings of 3rd International Conference on Zirconia Tokyo 1986. (1987)

    • Related Report
      1986 Annual Research Report

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Published: 1987-03-31   Modified: 2016-04-21  

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