Impurity and vacancy segregation at symmetric tilt grain boundaries in Y2O3-doped ZrO2
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Segregation energies of impurity ions and oxygen vacancies at grain boundaries in Y2O3-doped ZrO2 as calculated from atomistic simulations using energy minimization and Monte Carlo methods are reported. Based on these energies, local defect equilibrium concentrations have been estimated. It is found that it is more energetically favorable for an yttrium ion to be accompanied by an oxygen vacancy at grain boundaries, although decrease in energy when associated with an oxygen vacancy differs from boundary to boundary. The segregation energy for a neutral defect complex consisting of a two yttrium ions and an oxygen vacancy at infinitely dilute concentration is highly correlated with the coordination environment of each site in the vicinity of the grain boundary (GB), and, in turn, GB energy. Although the estimated local equilibrium concentrations of these defects are similar, detailed analysis of the atomic coordination and defect distributions in the vicinity of a GB reveal that defect distributions, especially of oxygen vacancies, are dependent on the characteristics of the particular GB and that segregation in effect reduces lattice strains at the GB. Equilibrium concentration distributions of yttrium at grain boundaries are also given as a function of spatial resolution, and are useful for interpretation of experimental results.
KeywordsOxygen Vacancy Grain Boundary Coordination Environment Defect Complex Coincidence Site Lattice
The authors are grateful for useful discussions with Drs H. Matsubara and C. A. J. Fisher at the Japan Fine Ceramics Center and Prof. K. Matsunaga at Kyoto University. This study is in part supported by Grant-in-Aid for Scientific Research on Priority Areas “Atomic Scale Modification” (No. 474) from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
- 1.Hondros ED, Seah MP (1983) In: Cahn RW, Haasen P (eds) Physical metallurgy. Amsterdam, North-HollandGoogle Scholar
- 3.Hofmann S (1987) J Chim Phys Phys Chim Biol 84:141Google Scholar
- 4.Sutton AP, Balllufi RW (1995) Interfaces in crystalline materials. Oxford University Press, New YorkGoogle Scholar
- 11.Backhaus-Ricoult M, Badding M, Thibault Y (2006) Ceram Trans 179:173Google Scholar
- 25.Oyama T, Yoshiya M, Matsubara H, Matsunaga K (2005) Phys Rev B 71:224105-1Google Scholar
- 27.Zapata-Solvas E, de Bernardi-Martín S, Gómez-García D (2010) Int J Mater Res 101:84Google Scholar
- 44.Durá OJ, López de la Torre MA, Vázquez L, Chaboy J, Boada R, Rivera-Calzada A, Santamaria J, Leon C (2010) Ionic conductivity of nanocrystalline yttria-stabilized zirconia: Grain boundary and size effects. Phys Rev B 81:184301-1-9Google Scholar
- 56.Yoshiya M, Shimizu K, Oyama T, Yasuda H (in preparation)Google Scholar
- 57.Oyama T, Wada N, Takagi H, Yoshiya M (2010) Phys Rev B 82:134107-1Google Scholar