Structure, energy and solute segregation behaviour of [110] symmetric tilt grain boundaries in yttria-stabilized cubic zirconia

Abstract

Yttria-stabilized cubic zirconia bicrystals with [110] symmetric tilt grain boundaries are systematically fabricated by the diffusion bonding method. It is revealed that the grain-boundary atomistic structures, excess energies and solute segregation behaviours are strongly dependent on the macroscopic geometries of the boundaries. High-resolution transmission electron microscopy combined with lattice statics calculations suggests that the grain-boundary structures are characterized by the accumulation of coordination-deficient cation sites at their cores, whose densities have a clear correlation with excess energies and amounts of solute segregation. The orientation dependence of grain-boundary properties in cubic zirconia can thus be linked and understood via local grain-boundary atomistic structures with the characteristic miscoordinated cation sites.

Acknowledgements

The authors would like to express their gratitude to Professor T. Sakuma for useful discussions. The authors also thank Dr C. Iwamoto for his assistance in the operation of the atomic-resolution high-voltage electron microscope, and Mr K. Yokoyama and Mr T. Watanabe for their assistance in grain-boundary energy evaluations. The authors also wish to thank Dr J. Gale for allowing us to use the GULP program code. N.S. and F.O. are Japan Society for the promotion of Science (JSPS) Research Fellows. This work was financially supported by a grant-in-aid for JSPS Fellows from the Ministry of Education, Culture, Sports, Science and Technology, Japan. A part of this work was also supported by a grant-in-aid for scientific research and special coordination funds from the Ministry of Education, Culture, Sports, Science and Technology, Japan, and PRESTO, Japan Science and Technology Corporation.