Phase equilibrium, Lattice parameter, solid solutions

How to Cite

Kornienko , O., Bykov, O., SameliukА., & Yurchenko, Y. (2020). PHASE RELATION STUDIES IN THE CeO2-La2O3-Eu2O3 SYSTEM AT 1250 °С. Ukrainian Chemistry Journal, 86(3), 35-47.


Using the methods of physicochemical analysis (XRD, petrography, scanning electron microscopy analyses) phase equilibria were firstly investigated in the ternary system СeO2–La2O3–Eu2O3 system at 1250 ºС. It was established that in the system there exist fields of solid solutions based on cubic with fluorite-type structure (F) and cubic (С) and monoclinic (B) modification Eu2O3 and hexagonal (A) modification of La2O3. No new phases were found. The refined lattice parameters of the unit cells for solid solutions for the systems were determined. The cubic ceria-based solid solution has a fluorite-type structure and homogeneity field shows the maximum extension. It forms solid solutions of substitution type with phases of binary systems. The boundary of the homogeneity field of F-phase is curved from the center of triangle toward the CeO2 corner and passes through appropriate points in the binary CeО2-Eu2O3(100-69 mol % CeO2) and CeO2–La2O3 (100-51 mol% CeO2) systems. The lattice parameters for F phase vary from  а = 0.5409 nm in pure СеО2toа = 0.5512 nm in two-phase sample (F + C) containing 55 mol % CeО2-22.5 mol % La2O3-22.5 mol % Eu2O3and to а = 0.5526 nm in  three-phase sample (F + В  + C) containing 40 mol % CeО2-30 mol % La2O3-30 mol % Eu2O3 and to а = 0.5532 nm in  three-phase sample (А + F + В) containing 30 mol % CeО2-35 mol % La2O3-35 mol % Eu2O3along the section CeO2 ( 50 mol % La2O3-35 mol % Eu2O3). The lattice parameters for F phase vary from  а = 0.5409 nm in pure СеО2 to а = 0.5444 nm nm in two-phase sample (F + C), containing 70 mol % CeО2-3 mol % La2O3-27 mol % Eu2O3and to а = 0.5465 nm in  three-phase sample (F + В  + C) containing 20 mol % CeО2-8 mol % La2O3-72 mol % Eu2O3. The homogeneity field of solid solution based on A-La2O3 extends to 17 mol % СеO2 and 20 mol % Eu2O3 in the corresponding binary systems and locates near the composition 5 mol % CeO2-90 mol % La2O3-5 mol % Eu2O3 on the section La2О3 - (50 mol % CeО2-50 mol % Eu2О3). The boundary of the homogeneity field of B- Eu2O3 phase passes through appropriate points in the binary CeО2-EuO3 (0-1 mol% CeO2) and–Eu2O3 (0-25 mol% La2O3) systems. The isothermal section of the CeO2– La2O3–Eu2O3 system at 1250°C contains four three-phase regions (A+F+B, F+B+C) and five two-phase regions (F+A, A+B, F+B, B+C, F+C).


1. Pinheiro D., Devi K. R. S., Karthik K., Jose A. and Sugunan S. Phytogenic CeO2-Sm2O3 nanocomposites with enhanced catalytic activity for reductionof 4-nitrophenol. Mater. Res. Express. 2019, 6: 08.

2. Sato K., Yugami H., Hashida T. Effect of rare-earth oxides on fracture properties of ceria ceramics. J. of Materials Science. 2004. 39: 5765.

3. Zhu B., Tahara Y., Yasunaga K., Matsui T., Hori F., Iwase A. Study on analysis crystal structure in CeO2 doped with Er2O3 or Gd2O3. Journal of Rare Earths. 2010.28:.164.

4. Kimpton J.,Randle T.H., Drennan J. Investigation of electrical conductivity as function of dopant-ion radius in the systems Zr0.75Ce0.08M0.17O1.92 (M = Nd, Sm,Gd, Dy, Ho, Y, Er, Yb, Sc). Solid State Ionics. 2002. 149: 89.

5. Anjana P. S., Joseph T., Sebastian M. T. Microwave dielectric properties of (1-x) CeO2-x RE2O3 (RE=La, Nd, Sm, Eu, Gd, Dy, Er, Tm, Yb, and Y) (0 ≤ x ≤1) ceramics. Journal of Alloys and Compounds. 2010. 490: 208.

6. Zhu B., Ohno H., Kosugi S., Hori F., Yasunaga K., Ishikawa N., Iwase A. Effects of swift heavy ion irradiation on the structure of Er2O3-doped CeO2. Nuclear Instruments and Methods in Physics Research. 2010. 268: 3199.

7. Garrido Pedrosa A.M., da Silva J.E.C., Pimentel P.M., Melo D.M.A.,. Silva F.R.G. Synthesis and optical investigation of systems involving mixed Ce and Er oxides. Journal of Alloys and Compounds. 2004. 374: 223.

8. Maschio S., Aneggi E., Trovarelli A., Sergo V. Influence of erbia or europia doping on crystal structure and microstructure of ceria-zirconia (CZ) solid solutions. Ceramics International. 2008. 34: 1327.

9. Ito T., Yoshino M., Iwasaki K., Matsui T., Nagasaki T. Photoluminescence of Er-containing metal oxide in U-band. Proceedings of International Symposium on Eco Topia Science. 2007. 128.

10. Sibieude, F., Hernandez, D. and Foex, M., C.R. Acad. Sci. 1974.Ser. C, 278, 1273

11. Brauer, G., Gradinger, H., Über heterotype Mischphasen bei Seltenerdoxyden. Journal Anorg. Algem. Chem. 1954.276: 209.

12. Bacquet G., Bouysset C. and Hernandez D. E.S.R. of Gd3+ in La2O3 and its solid solutions with CeO2. Journal Physique. 1976.37(12): 204

13. Bevan D.J.M. and Mann A.W. The crystal structure of Y7O6F9. Acta Cryst. 1975.B3:1411.

14. Minkova N. and Aslanian S.Isomorphic substitutions in the CeO2-La2O3 system at 850 °C.Cryst. Res. Technol. 1989.24: 351.

15. Sung B. J., Kil C.W., Hee L. C. The crystal structure of ionic conductor LaxCe1-xO2-x/2. Journal European Ceramic Society. 2004.24: 1291.

16. Morris B.C., Flavell W.R., Mackrodt W.C. and Morris M.A. Lattice parameter changes in the mixed oxide system LaxCe1-xO2-x/2 – a combined experimental and theoretical study. Journal Mater. Chem. 1993., 3 (10): 1007.

17. Sibieude F., Schiffmacher G. and CaroP. Étude au microscope électronique de structures modulées dans les régions systéme La2O3-CeO2 riches en La2O3. J. Solid State Chemistry. 1978.23(3-4): 361.

18. Andrievskaya E.R., Kornienko O.A, Sameljuk A.V., Ali Sayir PhaseRelation Studies in the CeO2-La2O3System at 1100 to 1500 °С. Journal of the European Ceramic Society. – 2011. -31 (7): 1277.

19. Toropov S. А. Phase Diagrams of the Refractory Oxide Systems, Binary systems, chapter 3/ S. А. Toropov. – L:, Nauka, 1987. – 264 p.

20. Kuto T. Oxygen Ion conduction of fluorite-Type Ce1-xLnxO2-x/2 (Ln= lanthanide Element) / T. Kuto, H. Obayashi. Journal Electrochem Soc. 1975. 142.

21. Yamamura H.,Nishino H., Kakinuma K., Nomura K. Crystal phase and electrical conductivity in the pyrochlore-type composition systems, Ln2Ce2O7 (Ln = La, Nd, Sm, Eu, Gd, Y and Yb). Jounnal of the Ceram. Soc. of Japan. 2003.111: 902.

22. Kumar B. A., Sankaranarayanan V. Ionic transport properties in nanocrystalline Ce0.8A0.2O2-δ (with A =Eu, Gd, Dy, and Ho) materials. Nanoscale Res Lett. 2010. 5: 637.

23. Andrievskaya E.R., Kornienko O. A. Sameljuk A.V., Sayir A. PhaseRelation Studies in the CeO2-Eu2O3System at 600 to 1500 °С. Journal of the European Ceramic Society. 2020.40: 751.

24. Andrievskaya E.R., Kornienko O.A., Kryuchko A.V., Bogatyryova J.D. Phase reactions and properties of phases in the La2O3-Eu2O3 system at temperature of 1500 С.Abstract of IX International Conference “Materials and Coatings for Extreme Environments Performance: Investigations, Applications, Ecologically Safe Technologies for their Production and Utilization”. 2016. Kiev, Ukraine, 2016. – Р. 21.

25. Schneider S. J. Phase equilibria in systems the rare-earth oxides. Part II. Solid state reaction in trivalent rare-earth oxide systems / S. J. Schneider, R. S. Roth // Physics and chemistry. – 1960. – Vol. 64A, No. 4. – P. 318–332.

26. Andrievskaya E. R. Phase equilibriums in systems of hafnia, zirconia, and yttria with REE oxides: Моnograph., Кyiv : Naukova Dumka, (2010), 470.


Download data is not yet available.