Transported Entropy in Zirconia with 3 to 12 Mole Percent Yttria

Seebeck coefficients were measured for the cell (T sub(1),p) Pt!O sub(2)(g)!YSZ!O sub(2) (g)!Pt(T sub(2),p). The electrolyte was yttria-stabilized zirconia (YSZ) and the content of yttria in the electrolyte varied between 3 and 12 mole percent (m/o). Thus tetragonal and cubic crystal structures were investigated. Different sintering temperatures and times were used in sample preparation to produce different grain sizes in the electrolyte. The reference temperature is T sub(1) = 1000 degree C and T sub(2) has been varied up to 1200 degree C. Two different oxygen pressures were used. The transported entropy of oxygen ions, S sub(O(sub 2-1)), calculated from the Seebeck coefficient at 1273 K, is constant and equal to 42 plus or minus 2 J K super(-1) F super(-1) for all samples. The heat of transport q is irrelevant to the Seebeck coefficient, as q is related to diffusion, which does not take place. The Thomson coefficient of the material is estimated to be 18 J K super(-1) F super(-1). This result is used to compare values for the transported entropy of oxygen ions, S sub(O(sub 2-1)), calculated from literature reports. Common expressions from thermoelectric theory are rejected on theoretical as well as experimental grounds.