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Mechanism of structure formation in samarium and holmium titanates prepared from mechanically activated oxides

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Abstract

We have studied the formation mechanism and phase transitions of samarium and holmium titanates prepared from mechanically activated oxide mixtures with the overall compositions Sm2(Ho2)Ti2O7 and Sm2TiO5. Mechanical activation of oxide mixtures leads to the formation of amorphous solid phases which crystallize in a distorted pyrochlore-like structure and contain OH groups on the oxygen site and structural vacancies up to 1000°C. In the range 800–1000°C, Sm2−x Ti1−y O5−δ (OH) n (x < 0.02; y < 0.08; δ, n < 0.19) converts to a distorted orthorhombic phase as a result of the relaxation of internal stress and removal of OH groups. Above 1000°C, the phases studied have the compositions Sm2(Ho2)Ti2O7 and Sm2TiO5 and ordered pyrochlore-like and orthorhombic structures, respectively. The lattice parameters of the titanates have been measured in the range 800–1350°C. The internal stress produced by mechanical activation in the phases studied here fully relaxes by ∼1300°C.

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References

  1. Tuller, H.L. and Moon, P.K., Fast-Ion Conductors: Future Tends, Mater. Sci. Eng., A, 1988, vol. 1, pp. 171–191.

    Article  Google Scholar 

  2. Tuller, H.L, Ionic and Mixed Conductors: Materials Design and Optimization, Proc. 17th Riso Int. Symp. on Materials Science, Roskilde, 1996, pp. 139–153.

  3. Ivanov-Shitz, A.K. and Murin, I.V., Ionika tverdogo tela (Solid State Ionics), St. Petersburg: S.-Peterburg. Univ., 2000, vol. 1, pp. 128–135.

    Google Scholar 

  4. Lyashenko, L.P., Kolbanev, I.V., Shcherbakova, L.G., et al., Effect of a Nonequilibrium State on Phase Relations in the System TiO2-Sc2O3 (40–50 mol % Sc2O3), Neorg. Mater., 2004, vol. 40, no. 8, pp. 955–962 [Inorg. Mater. (Engl. Transl.), vol. 40, no. 8, pp. 833–839].

    Article  Google Scholar 

  5. Lyashenko, L.P., Nikonov, Yu.P., Raevskii, A.V., and Shcherbakova, L.G., Formation Mechanism of Fluorite-like Phases in the TiO2-R2O3 (R = Y, Er, Sc) Systems, Materialovedenie, 1999, no. 1, pp. 29–33.

  6. Sobolev, B.P., Golubev, A.M., and Herrero, P., Fluorite M1−x RxF2+x Phase (M = Ca, Sr, Ba; R = Rare Earth Elements) as Nanostructured Materials, Kristallografiya, 2003, vol. 48, no. 1, pp. 148–169.

    Google Scholar 

  7. Shcherbakova, L.G., Glushkova, V.B., Lyashenko, L.P., et al., High-Temperature Phase Relations and Diffusion in the Systems Er2O3-TiO2 and Y2O3-TiO2, Dokl. Akad. Nauk SSSR, Ser. Khim., 1977, vol. 236, no. 6, pp. 1390–1393.

    CAS  Google Scholar 

  8. Minervini, L., Grimes, R.W., Tabira, Y., et al., The Oxygen Positional Parameter in Pyrochlores and Its Dependence on Disorder, Philos. Mag. A, 2002, vol. 82, no. 1, pp. 123–135.

    Article  CAS  Google Scholar 

  9. Wuensch, B.J., Eberman, K.W., Heremans, C., et al., Connection between Oxygen-Ion Conductivity of Pyrochlore Fuel-Cell Materials and Structural Change with Composition and Temperature, Solid State Ionics, 2000, vol. 129, pp. 111–133.

    Article  CAS  Google Scholar 

  10. Eberman, K.W., Wuensch, B.J., and Jorgensen, J.D., Order-Disorder Transformations Induced by Composition and Temperature Change in (SczYb1−z )2Ti2O7 Pyrochlores, Prospective Fuel Cell Materials, Solid State Ionics, 2002, vol. 148, pp. 521–526.

    Article  CAS  Google Scholar 

  11. Kosacki, I., Anderson, H.U., Mizutani, Y., and Ukai, K., Nonstoichiometry and Electrical Transport in Sc-Doped Zirconia, Solid State Ionics, 2002, vols. 152–153, pp. 431–438.

    Article  Google Scholar 

  12. Okamota, M., Akimune, Y., Furuya, F., et al., Phase Transition and Electrical Conductivity of Scandia-Stabilized Zirconia Prepared by Spark Plasma Sintering Process, Solid State Ionics, 2005, vol. 176, pp. 675–680.

    Article  CAS  Google Scholar 

  13. Stanek, C.R., Minervini, L., and Grimes, R.W., Nonstoichiometry in A2B2O7 Pyrochlores, J. Am. Ceram. Soc., 2002, vol. 85, no. 11, pp. 2792–2798.

    Article  CAS  Google Scholar 

  14. Powder Diffraction File, Swarthmore: Joint Committee on Powder Diffraction Standards, cards 23-0283, 16-400, 22-1306, 36-0384, 40-0974.

  15. Soedineniya redkozemel’nykh elementov (Rare-Earth Compounds), Orlovskii, V.P. and Chudinova, N.N., Eds., Moscow: Nauka, 1984.

    Google Scholar 

  16. Lazarev, A.N., Kolebatel’nye spektry i stroenie silikatov (Vibrational Spectra and Structure of Silicates), Leningrad: Nauka, 1968.

    Google Scholar 

  17. Diagrammy sostoyaniya sistem tugoplavkikh oksidov: Spravochnik (Phase Diagrams of Refractory Oxide Systems: A Handbook), issue 5: Dvoinye sistemy (Binary Systems), Galakhov, F.Ya., Ed., Leningrad: Nauka, 1985, part 1.

    Google Scholar 

  18. Shannon, R.D. and Prewitt, C.T., Effective Ionic Radii in Oxides and Fluorides, Acta Crystallogr., Sect. B: Struct. Crystallogr. Cryst. Chem., 1969, vol. 25, no. 5, pp. 925–946.

    Article  CAS  Google Scholar 

  19. Shannon, R.D., Revised Effective Ionic Radii and Systematic Studies of Interatomic Distances in Halides and Chalcogenides, Acta Crystallogr., Sect. A: Cryst. Phys., Diffr., Theor. Gen. Crystallogr., 1976, vol. 32, no. 5, pp. 751–767.

    Article  Google Scholar 

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Authors and Affiliations

  1. Institute of Problems of Chemical Physics, Russian Academy of Sciences, pr. Akademika Semenova 1, Chernogolovka, Moscow oblast, 142432, Russia

    L. P. Lyashenko, E. I. Knerel’man & G. I. Davydova

  2. Semenov Institute of Chemical Physics, Russian Academy of Sciences, ul. Kosygina 4, Moscow, 119991, Russia

    L. G. Shcherbakova & I. V. Kolbanev

Authors
  1. L. P. Lyashenko
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  2. L. G. Shcherbakova
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  3. I. V. Kolbanev
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  4. E. I. Knerel’man
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  5. G. I. Davydova
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Original Russian Text © L.P. Lyashenko, L.G. Shcherbakova, I.V. Kolbanev, E.I. Knerel’man, G.I. Davydova, 2007, published in Neorganicheskie Materialy, 2007, Vol. 43, No. 1, pp. 51–59.

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Lyashenko, L.P., Shcherbakova, L.G., Kolbanev, I.V. et al. Mechanism of structure formation in samarium and holmium titanates prepared from mechanically activated oxides. Inorg Mater 43, 46–54 (2007). https://doi.org/10.1134/S0020168507010116

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  • DOI: https://doi.org/10.1134/S0020168507010116

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