The conduction properties at high temperatures were investigated by using electrochemical methods. The conductivity of Ca(Ti,Sc)O3 was the highest ever reported for a CaTiO3-based oxide, and was comparable to that of ZrO2-8%Y2O3 at 1073 to 1273K. The conductivity of Ca(Ti,Ga)O3 was of the same order as that of Ca(Ti,Al)O3. The mobile ions in the specimens were mainly oxide ions. Hole conduction was present in the total conductivity under normal ambients, and electronic conduction appeared in the region of low O partial pressure. In the intermediate range of O partial pressures, an ionic conduction domain within which the conductivity was independent of the O partial pressure was also observed. In particular, Sc-doped specimens not only exhibited a higher conductivity, but also a wider ionic domain and higher ion transference number than did other CaTiO3-based solid solutions; under fuel-cell conditions.

Conduction Properties of Ca(Ti1-xMx)O3 at Elevated Temperatures. S.Hashimoto, H.Kishimoto, H.Iwahara: Solid State Ionics, 2001, 139[3-4], 179-87