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Thermochemistry of lanthanum zirconate pyrochlore

Published online by Cambridge University Press:  31 January 2011

A.V. Radha ,
Sergey V. Ushakov  and
Alexandra Navrotsky
A.V. Radha
Affiliation:
Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California at Davis, Davis, California 95616
Sergey V. Ushakov
Affiliation:
Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California at Davis, Davis, California 95616
Alexandra Navrotsky*
Affiliation:
Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California at Davis, Davis, California 95616
*
a) Address all correspondence to this author. e-mail: [email protected]
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Abstract

A thermodynamic study was carried out to resolve discrepancies in the enthalpy of formation and related parameters for lanthanum zirconate pyrochlore. The homogeneity field for single phase pyrochlore formation was determined to be ∼33–35 mol% La2O3 at 1500 °C. High-temperature oxide melt drop solution calorimetry was performed in sodium molybdate and lead borate solvents on three compositions ranging from La1.98Zr2.01O7 to La2.07Zr1.95O7. The enthalpy of formation from oxides at 25 °C, ΔH0f,ox, for stoichiometric lanthanum zirconate pyrochlore is −107.3 ± 5.1 kJ/mol, and the standard enthalpy of formation from elements, ΔH0f,el, is −4102.2 ± 6.0 kJ/mol. La2Zr2O7 pyrochlore was found by differential thermal analysis to be stable up to its melting point. The melting point and the fusion enthalpy of La2Zr2O7 pyrochlore were measured as 2295 ± 10 °C and ∼350 kJ/mol, respectively.

Keywords

CalorimetryDifferential thermal analysis (DTA)
Type
Articles
Information
Journal of Materials Research , Volume 24 , Issue 11 , November 2009 , pp. 3350 - 3357
Copyright
Copyright © Materials Research Society 2009

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References

1.Labrincha, J.A., Frade, J.R., and Marques, F.M.B.: Lanthanum zirconium oxide (La2Zr2O7) formed at ceramic electrode/YSZ contacts. J. Mater. Sci. 28, 3809 (1993).CrossRefGoogle Scholar
2.McCauley, R.A. and Hummel, F.A.: Luminescence as an indication of distortion in A23+B24+O7 type pyrochlores. J. Lumin. 6, 105 (1973).CrossRefGoogle Scholar
3.Padture, N.P., Gell, M., and Jordan, E.H.: Thermal-barrier coatings for gas-turbine engine applications. Science 296, 280 (2002).CrossRefGoogle ScholarPubMed
4.Korf, S.J., Koopmans, H.J.A., Lippens, B.C., Jr., Burggraaf, A.J., and Gellings, P.J.: Electrical and catalytic properties of some oxides with the fluorite or pyrochlore structure: Carbon monoxide oxidation on some compounds derived from gadolinium zirconium oxide (Gd2Zr2O7). J. Chem. Soc., Faraday Trans. 83, 1485 (1987).CrossRefGoogle Scholar
5.Labrincha, J.A., Frade, J.R., and Marques, F.M.B.: Proton conduction in La2Zr2O7-based pyrochlore materials. Solid State Ionics 99, 33 (1997).CrossRefGoogle Scholar
6.Leppaevuori, S., Lozinski, A.H., and Uusimaki, A.: A thick-film pyroelectric PLZT ceramic sensor. Sens. Actuators, A 47, 391 (1995).CrossRefGoogle Scholar
7.McCauley, R.A.: Structural characteristics of pyrochlore formation. J. Appl. Phys. 51, 290 (1980).CrossRefGoogle Scholar
8.Bolech, M., Cordfunke, E.H.P., Van Genderen, A.C.G., Van Der Laan, R.R., Janssen, F.J.J.G., and Miltenburg, J.C. Van: The heat capacity and derived thermodynamic functions of La2Zr2O7 and Ce2Zr2O7 from 4 to 1000 K. J. Phys. Chem. Solids 58, 433 (1997).CrossRefGoogle Scholar
9.Sedmidubsky, D., Benes, O., and Konings, R.J.M.: High temperature heat capacity of Nd2Zr2O7 and La2Zr2O7 pyrochlores. J. Chem. Thermodyn. 37, 1098 (2005).CrossRefGoogle Scholar
10.Korneev, V.R., Glushkova, V.B., and Keler, E.K.: Heats of formation of rare-earth zirconates. Izv. Akad. Nauk SSSR. Neorg. Mater. 7, 886 (1971).Google Scholar
11.Bolech, M., Cordfunke, E.H.P., Janssen, F.J.J.G., and Navrotsky, A.: Standard enthalpy of formation of lanthanum zirconate. J. Am. Ceram. Soc. 78, 2257 (1995).CrossRefGoogle Scholar
12.Rog, G. and Kozlowska-Rog, A.: Determination of the standard molar Gibbs energy of formation of lanthanum zirconate by a galvanic cell involving lanthanum beta-alumina electrolyte. J. Chem. Thermodyn. 34, 1311 (2002).CrossRefGoogle Scholar
13.Jacob, K.T., Dasgupta, N., and Waseda, Y.: Composition-graded solid electrolyte for determination of the Gibbs energy of formation of lanthanum zirconate. J. Am. Ceram. Soc. 81, 1926 (1998).CrossRefGoogle Scholar
14.Navrotsky, A.: Thermochemical insights into refractory ceramic materials based on oxides with large tetravalent cations. J. Mater. Chem. 15, 1883 (2005).CrossRefGoogle Scholar
15.Navrotsky, A., and Ushakov, S.V.: Thermodynamics of oxide systems relevant to alternative gate dielectrics. Mater. Fundam. Gate Dielectr. (Springer, Dordrecht, The Netherlands, 2005), p. 57.CrossRefGoogle Scholar
16.Ushakov, S.V., Navrotsky, A., Tangeman, J.A., and Helean, K.B.: Energetics of defect fluorite and pyrochlore phases in lanthanum and gadolinium hafnates. J. Am. Ceram. Soc. 90, 1171 (2007).CrossRefGoogle Scholar
17.Wang, C., Fabrichnaya, O., Zinkevich, M., Du, Y., and Aldinger, F.: Experimental study and thermodynamic modelling of the ZrO2- LaO1.5 system. Calphad 32, 111 (2008).CrossRefGoogle Scholar
18.Ewing, R.C., Weber, W.J., and Lian, J.: Nuclear waste disposalpyrochlore (A2B2O7): Nuclear waste form for the immobilization of plutonium and minor actinides. J. Appl. Phys. 95, 5949 (2004).CrossRefGoogle Scholar
19.Lian, J., Zu, X.T., Kutty, K.V.G., Chen, J., Wang, L.M., and Ewing, R.C.: Ion-irradiation-induced amorphization of La2Zr2O7pyrochlore. Phys. Rev. B: Condens. Matter 66, 054108 (2002).CrossRefGoogle Scholar
20.Begg, B.D., Hess, N.J., Weber, W.J., Devanathan, R., Icenhower, J.P., Thevuthasan, S., and McGrail, B.P.: Heavy-ion irradiation effects on structures and acid dissolution of pyrochlores. J. Nucl. Mater. 288, 208 (2001).CrossRefGoogle Scholar
21.Sickafus, K.E., Minervini, L., Grimes, R.W., Valdez, J.A., Ishimaru, M., Li, F., McClellan, K.J., and Hartmann, T.: Radiation tolerance of complex oxides. Science 289, 748 (2000).CrossRefGoogle ScholarPubMed
22.Williford, R.E., Weber, W.J., Devanathan, R., and Gale, J.D.: Effects of cation disorder on oxygen vacancy migration in Gd2Ti2O7. J. Electroceram. 3, 409 (1999).CrossRefGoogle Scholar
23.Minervini, L., Grimes, R.W., and Sickafus, K.E.: Disorder in pyrochlore oxides. J. Am. Ceram. Soc. 83, 1873 (2000).CrossRefGoogle Scholar
24.Chartier, A., Meis, C., Weber, W.J., and Corrales, L.R.: Theoretical study of disorder in Ti-substituted La2Zr2O7. Phys. Rev. B: Condens. Matter 65, 134116 (2002).CrossRefGoogle Scholar
25.Lian, J., Wang, L., Chen, J., Sun, K., Ewing, R.C., Farmer, J. Matt, and Boatner, L.A.: The order-disorder transition in ion-irradiated pyrochlore. Acta Mater. 51, 1493 (2003).CrossRefGoogle Scholar
26.Hess, N.J., Begg, B.D., Conradson, S.D., McCready, D.E., Gassman, P.L., and Weber, W.J.: Spectroscopic investigations of the structural phase transition in Gd2(Ti1yZry)2O7pyrochlores. J. Phys. Chem. B 106, 4663 (2002).CrossRefGoogle Scholar
27.Ushakov, S.V., Brown, C.E., and Navrotsky, A.: Effect of La and Y on crystallization temperatures of hafnia and zirconia. J. Mater. Res. 19, 693 (2004).CrossRefGoogle Scholar
28.Navrotsky, A.: Progress and new directions in high temperature calorimetry. Phys. Chem. Miner. 2, 89 (1977).CrossRefGoogle Scholar
29.Navrotsky, A.: Progress and new directions in high temperature calorimetry revisited. Phys. Chem. Miner. 24, 222 (1997).CrossRefGoogle Scholar
30.Sleight, A.W.: New ternary oxide of mercury with the pyrochlore structure. Inorg. Chem. 7, 1704 (1968).CrossRefGoogle Scholar
31.Rouanet, A.: Zirconiumdioxide-lanthanide oxide systems close to the melting point. Rev. Int. Hautes Temp. Refract. 8, 161 (1971).Google Scholar
32.Cheng, J. and Navrotsky, A.: Enthalpies of formation of LaBO3 perovskites (B = Al, Ga, Sc, and In). J. Mater. Res. 18, 2501 (2003).CrossRefGoogle Scholar
33.Radha, A.V., Bomati-Miguel, O., Ushakov, S.V., Navrotsky, A., and Tartaj, P.: Surface enthalpy, enthalpy of water adsorption, and phase stability in nanocrystalline monoclinic zirconia. J. Am. Ceram. Soc. 92, 133 (2008).CrossRefGoogle Scholar
34.Molodetsky, I., Navrotsky, A., DiSalvo, F., and Lerch, M.: Energetics of oxidation of oxynitrides: Zr-N-O, Y-Zr-N-O, Ca-Zr-N-O, and Mg-Zr-N-O. J. Mater. Res. 15, 2558 (2000).CrossRefGoogle Scholar
35.Molodetsky, I. and Navrotsky, A.: The energetics of cubic zirconia from solution calorimetry of yttria- and calcia-stabilized zirconia. Z. Phys. Chem. 207, 59 (1998).CrossRefGoogle Scholar
36.Pitcher, M.W., Ushakov, S.V., Navrotsky, A., Woodfield, B.F., Li, G.S., Boerio-Goates, J., and Tissue, B.M.: Energy crossovers in nanocrystalline zirconia. J. Am. Ceram. Soc. 88, 160 (2005).CrossRefGoogle Scholar
37.Lee, T.A., Navrotsky, A., and Molodetsky, I.: Enthalpy of formation of cubic yttria-stabilized zirconia. J. Mater. Res. 18, 908 (2003).CrossRefGoogle Scholar
38.Ellison, A.J.G. and Navrotsky, A.: Enthalpy of formation of Zircon. J. Am. Ceram. Soc. 75, 1430 (1992).CrossRefGoogle Scholar
39.Bularzik, J., Navrotsky, A., DiCarlo, J., Bringley, J., Scott, B., and Trail, S.: Energetics of lanthanum strontium copper oxide (La2xSrxCuO4y) solid solutions (0.0 x 1.0). J. Solid State Chem. 93, 418 (1991).CrossRefGoogle Scholar
40.Lakiza, S.M. and Lopato, L.M.: Phase diagram of the Al2O3-ZrO2- La2O3system. J. Eur. Ceram. Soc. 25, 1373 (2005).CrossRefGoogle Scholar
41.Cordfunke, E.H.P. and Konings, R.J.M.: Thermochemical Data for Reactor Materials and Fission Products (North-Holland, Amsterdam, The Netherlands, 1990).Google Scholar
42.Cheng, J., Navrotsky, A., Zhou, X-D., and Anderson, H.U.: Enthalpies of formation of LaMO3perovskites (M = Cr, Fe, Co, and Ni). J. Mater. Res. 20, 191 (2005).CrossRefGoogle Scholar
43.Yokokawa, H., Sakai, N., Kawada, T., and Dokiya, M.: Chemical thermodynamic considerations on reactivity of perovskite oxide electrodes with zirconia. Denki Kagaku Oyobi Kogyo Butsuri Kagaku 57, 821 (1989).Google Scholar
44.Wang, C., Zinkevich, M., and Aldinger, F.: The zirconia-hafnia system: DTA measurements and thermodynamic calculations. J. Am. Ceram. Soc. 89, 3751 (2006).CrossRefGoogle Scholar
45.Lide, D.P.: Handbook of Chemistry and Physics, 83rd ed. (CRC Press, Boca Raton, FL, 2002–2003).Google Scholar
46.Zoz, E.I., Gavrish, A.M., and Gulko, N.V.: Phase formation in the zirconium oxide (hafnium oxide)-lanthanum oxide system. Izv. Akad. Nauk SSSR Neorg. Mater. 14, 109 (1978).Google Scholar
47.Portnoi, K.I., Timofeeva, N.I., Salibekov, S.E., and Romanovich, I.V.: Synthesis and study of the properties of complex oxides of rareearth elements and zirconium. Izv. Akad. Nauk SSSR Neorg. Mater. 8, 406 (1972).Google Scholar
48.Lin, T-H. and Yu, H-C.: Phase equilibria of systems Ln2O3(rare earth oxides)-ZrO2. I. Phase equilibria of the binary system La2O3-ZrO2. Guisuanyan Xuebao 3, 159 (1964).Google Scholar