Hostname: page-component-78c5997874-v9fdk Total loading time: 0 Render date: 2024-11-10T12:55:29.153Z Has data issue: false hasContentIssue false
  • English
  • Français

Energetics of rare-earth-doped hafnia

Published online by Cambridge University Press:  03 March 2011

Petra Simoncic  and
Alexandra Navrotsky
Petra Simoncic
Affiliation:
Nanomaterials in the Environment, Agriculture, and Technology Organized Research Unit (NEAT ORU) and Thermochemistry Facility, University of California at Davis, Davis, California 95616
Alexandra Navrotsky*
Affiliation:
Nanomaterials in the Environment, Agriculture, and Technology Organized Research Unit (NEAT ORU) and Thermochemistry Facility, University of California at Davis, Davis, California 95616
*
a) Address all correspondence to this author. e-mail: anavrotsky@ucdavis.edu
Get access

Abstract

The enthalpies of formation of rare-earth (RE)-doped Hf1−xRExO2−x/2 solid solutions (RE = Sm, Gd, Dy, Yb; x = 0.25 to 0.62) with respect to the oxide end members, monoclinic HfO2 and C-type REO1.5, were determined using oxide melt solution calorimetry. The enthalpies of formation fit a function quadratic in composition. The strongly negative interaction parameters in all solid solutions confirm a strong tendency for short-range order. Though strongly negative for all systems, the interaction parameters become less negative with increasing ionic potential (decreasing RE radius). Crystallization energetics were investigated for amorphous coprecipitation products with x = 0.4. The energy difference between the crystalline (fluorite and pyrochlore) and amorphous phases decreases with decreasing dopant radius. This suggests that systems doped with small RE ions have more similar local structures in the fluorite and amorphous phases. These observations may result in a smaller kinetic barrier to recrystallization and account for the greater radiation resistance of materials with smaller RE cations.

Keywords

CalorimetryIonic conductorLanthanide
Type
Articles
Information
Journal of Materials Research , Volume 22 , Issue 4 , April 2007 , pp. 876 - 885
Copyright
Copyright © Materials Research Society 2007

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1Wang, J., Li, H.P., and Stevens, R.: Hafnia and hafnia-toughened ceramics. J. Mater. Sci. 27, 5397 (1992).CrossRefGoogle Scholar
2Trubelja, M.F. and Stubican, V.S.: Ionic conductiviy of the fluorite-type hafnia-R2O3 solid solutions. J. Am. Ceram. Soc. 74, 2489 (1991).CrossRefGoogle Scholar
3Hartmanova, V.S.M. and Glushkova, V.B.: Electrical behaviour of HfO2 stabilized with rare earths. Solid State Ionics 36, 189 (1989).Google Scholar
4Lee, T.A. and Navrotsky, A.: Enthalpy of formation of cubic yttria-stabilized hafnia. J. Mater. Res. 19, 1855 (2004).CrossRefGoogle Scholar
5Schieltz, J.D., Patterson, J.W., and Wilder, D.R.: Electrolytic behavior of yttria-stabilized hafnia. J. Electrochem. Soc. 118, 1257 (1971).CrossRefGoogle Scholar
6Glushkova, V.B. and Kravchinskaya, M.V.: HfO2-based refactory compounds and solid solutions. Ceram. Int. 11, 56 (1985).CrossRefGoogle Scholar
7Paputskii, Y.N., Krzhizhanovaskaya, V.A., and Glushkova, V.B.: Enthalpy of formation of rare earth hafnates and zirconates. Inorg. Mater. 10, 1338 (1974).Google Scholar
8Lee, T.A., Navrotsky, A., and Molodetsky, I.: Enthalpy of formation of cubic yttria-stabilized zirconia (c-YSZ). J. Mater. Res. 18, 908 (2003).CrossRefGoogle Scholar
9Litton, D.A., Ulion, N.E., Trubelja, M.F., Maloney, M.J., and Warrier, S.G.: Thermal barrier coating with low thermal conductivity. U.S. Patent No. 6 730 422 ( 2004).Google Scholar
10Jeon, S., Im, K., Yang, H., Sim, H., Choi, S., Jang, T., and Hwang, H.: Excellent electrical characteristics of lanthanide (Pr, Nd, Sm, Gd, and Dy) oxide and lanthanide doped oxide for MOS gate dielectric applications. IEEE Electron Devices Meeting (IEDM Technical Digest International, Washington, DC, 2001), pp. 20.6.1–20.6.4.Google Scholar
11Ewing, R.C., Lian, J., and Wang, L.M.: Ion beam-induced amorphization of the pyrochlore structure-type: a review, in Radiation Effects and Ion-Beam Processing of Materials, edited by Wang, L.M., Fromknecht, R., Snead, L.L., Downey, D.F. and Takahashi, H. (Mater. Res. Soc. Symp. Proc. 792, Warrendale, PA, 2003), p. 37.Google Scholar
12Helean, K.B., Navrotsky, A., Lian, J., and Ewing, R.C.: Thermochemical investigations of zirconolite, pyrochlore and brannerite: Candidate materials for the immobilization of plutonium, in Scientific Basis for Nuclear Waste Management XXVII, edited by Oversby, V.M. and Werme, L.O. (Mater. Res. Soc. Symp. Proc. 807, Warrendale, PA, 2004), p. 297.Google Scholar
13Ewing, R.C., Weber, W.J., and Lian, J.: Nuclear waste disposal—pyrochlore (A2B2O7): Nuclear waste form for the immobilization of plutonium and minor actinides. J. Appl. Phys. 95, 5949 (2004).CrossRefGoogle Scholar
14Lian, J., Helean, K.B., Kennedy, B.J., Wang, L.M., Navrotsky, A., and Ewing, R.C.: Effect of structure and thermodynamic stability on the response of lanthanide stannate pyrochlores to ion-beam radiation. J. Phys. Chem. B 110, 2343 (2006).CrossRefGoogle Scholar
15Navrotsky, A.: Recent progress and new directions in high temperature calorimetry. Phys. Chem. Min. 2, 89 (1977).CrossRefGoogle Scholar
16Navrotsky, A.: Progress and new directions in high temperature calorimetry revisited. Phys. Chem. Min. 24, 22 (1997).CrossRefGoogle Scholar
17Larson, A.C. and Von Dreele, R.B.: General Structure Analysis System (GSAS), Los Alamos National Laboratory Report LAUR 86-748 ( 2000).Google Scholar
18MacHale, J.M., Kowach, G.R., Navrotsky, A., and DiSalvo, F.J.: Thermochemistry of metal nitrides in the Ca/Zn/N system. Chem. Eur. J. 2, 1514 (1996).CrossRefGoogle Scholar
19 Standard Reference Materials 720, Synthetic Sapphire (α–Al2O3) (National Bureau of Standards Certificates, Gaithersburg, MD, 1982).Google Scholar
20Ushakov, S.V., Brown, C.E., and Navrotsky, A.: Effect of La and Y on crystallization of hafnia and zirconia. J. Mater. Res. 19, 693 (2004).CrossRefGoogle Scholar
21Helean, K.B. and Navrotsky, A.: Oxide melt solution calorimetry of rare earth oxides: Techniques, problems, cross-checks, successes. J. Thermal Anal. Calor. 69, 751 (2004).CrossRefGoogle Scholar
22Ushakov, S.V. (unpublished).Google Scholar
23Foex, M. and Traverse, J.P.: Study on polymorphism of rare earth sesquioxides at high temperature. Bull. Soc. Franc. Miner. Crist. 89, 184 1966, in French).Google Scholar
24Navrotsky, A., Benoist, L., and Lefebvre, H.: Direct calorimetric measurement of enthalpies of phase transitions at 2000–2400 °C in yttria and zirconia. J. Am. Ceram. Soc. 88, 2942 (2005).Google Scholar
25Katagiri, S., Ishizawa, N., and Marumo, F.: A new high temperature modification of face-centered cubic Y2O3. Powder Diffr. 8, 60 (1993).CrossRefGoogle Scholar
26Ushakov, S.V., Navrotsky, A., Tangeman, J.A., and Helean, K.B.: Energetics: Energetics of fluorite and pyrochlore phases in lanthanum and gadolinium hafnates. J. Am. Ceram. Soc. (in press).Google Scholar
27Helean, K.B., Ushakov, S.V., Brown, C.E., Navrotsky, A., Lian, J., Ewing, R.C., Farmer, J.M., and Boatner, L.A.: Formation enthalpies of rare earth titanate pyrochlores. J. Solid State Chem. 177, 1858 (2004).CrossRefGoogle Scholar
28Helean, K.B., Begg, B.D., Navrotsky, A., Ebbinghaus, B., Weber, W.J., and Ewing, R.C.: Enthalpies of formation of Gd2(Ti2−x Zrx )O7 pyrochlores, in Scientific Basis for Nuclear Waste Management XXIV edited by Hart, K.P. and Lumpkin, G.R. (Mater. Res. Soc. Symp. Proc. 663, Warrendale, PA, 2002), p. 691.Google Scholar
29Helean, K.B. (unpublished).Google Scholar
30Sickafus, K.E., Minervini, L., Grimes, R.W., Valdez, J.A., Ishimaru, M., Li, F., McClellan, K.J., and Hartmann, T.: Radiation tolerances of complex oxides. Science 289, 748 (2000).CrossRefGoogle ScholarPubMed
31Minervini, L. and Grimes, R.W.: Disorder in pyrochlore oxides. J. Am. Ceram. Soc. 83, 1873 (2000).CrossRefGoogle Scholar
32Chartier, A., Meis, C., Weber, W.J., and Corrales, L.R.: Theroretical study of disorder in Ti-substituted La2Zr2O7. Phys. Rev. B 65, 1341161 (2002).CrossRefGoogle Scholar
33Lian, J., Wang, L., Chen, J., Sun, K., Ewing, R.C., Farmer, J.M., and Boatner, L.A.: The order-disorder transition in ion-irradiated pyrochlore. Acta Mater. 51, 1493 (2003).CrossRefGoogle Scholar
34Moon, P.K. and Tuller, H.L.: Intrinsic fast oxygen ionic conductivity in the gadolinium zirconium titanium oxide (Gd2(Zrx Ti1−x )2O7) and yttrium zirconium titanium oxide (Y2(Zrx Ti1−x )2O7) pyrochlore systems, in Solid State Ionics edited by Nazri, G., Huggins, R.A. and Shriver, D.F. (Mater. Res. Soc. Symp. Proc. 135, Pittsburg, PA, 1989), p. 149.Google Scholar
35Chen, W., Lee, T.A., and Navrotsky, A.: Enthalpy of formation of yttria-doped ceria. J. Mater. Res. 20, 144 (2005).CrossRefGoogle Scholar