Effect of Y2O3 addition on the conductivity and elastic modulus of (CeO2)1 − x(YO1.5)x

Abstract The conductivity and elastic modulus of (CeO 2 ) 1 −  x (YO 1.5 ) x for x values of 0.10, 0.15, 0.20, 0.30, and 0.40 were investigated by experiments and molecular dynamics simulations. The calculated conductivity exhibited a maximum value at approximately 15 mol% Y 2 O 3 ; this trend agreed with that of the experimental results. In order to clarify the reason for the occurrence of the maximum conductivity, the paths for the transfer of oxygen vacancies were counted. The numerical result revealed that as the content of Y 2 O 3 dopant increases, the number of paths for the transfer of oxygen vacancies decreases, whereas the number of oxygen vacancies for conductivity increases . Thus, the trade-off between the increase in the number of vacancy sites and the decrease in the vacancy transfer was considered to be the reason for the maximum conductivity occurring at the Y 2 O 3 dopant content of approximately 15 mol%. The calculated elastic modulus also exhibited a minimum value at approximately 20 mol% Y 2 O 3 , which also agreed with the experimental results. It was shown that the Y–O–Y bonding energy increased with the increasing content of Y 2 O 3 dopant. Thus, the trade-off between the increase in the number of vacancy sites and that in the Y–O–Y bonding energy was considered to be the reason for the minimum elastic modulus occurring at the Y 2 O 3 dopant content of approximately 20 mol%.

[1]  F. Shimojo,et al.  Molecular dynamics studies of yttria stabilized zirconia. I: Structure and oxygen diffusion , 1992 .

[2]  宗宮 重行,et al.  Science and technology of zirconia III , 1988 .

[3]  A. Chatterjee,et al.  Molecular dynamics simulation of enhanced oxygen ion diffusion in strained yttria-stabilized zirconia , 1998 .

[4]  F. Shimojo,et al.  Molecular Dynamics Studies of Yttria Stabilized Zirconia. II. Microscopic Mechanism of Oxygen Diffusion , 1992 .

[5]  Hideaki Inaba,et al.  Molecular dynamics simulation of gadolinia-doped ceria , 1999 .

[6]  Raphaël Ihringer,et al.  Concept and technology of SOFC for electric vehicles , 2000 .

[7]  S. Chan,et al.  Ionic conductivities, sintering temperatures and microstructures of bulk ceramic CeO2 doped with Y2O3 , 2000 .

[8]  K. Kawamura,et al.  Molecular dynamics calculations on ceria-based solid electrolytes with different radius dopants , 2000 .

[9]  N. Minh.  Ceramic Fuel Cells , 1993 .

[10]  R. Drew,et al.  Wettability and spreading kinetics of molten aluminum on copper-coated ceramics , 2006 .

[11]  David J. Green,et al.  An Introduction to the Mechanical Properties of Ceramics , 1998 .

[12]  Y. Hirata,et al.  Thermal and mechanical properties of rare earth-doped ceria ceramics , 1999 .

[13]  Berend Smit,et al.  Molecular Dynamics Simulations , 2002 .

[14]  Hisashi Suzuki,et al.  Molecular Dynamics Study of Superlattice Superionic Conductor: Enhancement of Oxygen Ion Diffusion in YSZ , 1994 .

[15]  A. Atkinson,et al.  Mechanical behaviour of ceramic oxygen ion-conducting membranes , 2000 .

[16]  H. Yahiro,et al.  Electrical properties and reducibilities of ceria−rare earth oxide systems and their application to solid oxide fuel cell , 1989 .

[17]  T. Hashida,et al.  Effect of rare-earth oxides on fracture properties of ceria ceramics , 2004 .

[18]  A. Miyamoto,et al.  Materials design of perovskite-based oxygen ion conductor by molecular dynamics method , 2003 .

[19]  N. Sammes,et al.  Physical, chemical and electrochemical properties of pure and doped ceria , 2000 .