Experimental study of oxygen thermodiffusion in (Usub(0.7)Cesub(0.3))Osub(2-x)

Redistribution of oxygen has been investigated in (Usub(0.7)Cesub(0.3))Osub(2-x) mixed oxide subjected to a temperature gradient in laboratory experiments. Cylindrical sintered oxide specimens were exposed to temperatures up to 13000C with a longitudinal thermal gradient of about 4000C/cm. The most interesting feature of the experimental set-up is a solid state electrochemical gauge (ThO2-Y2O3), placed in the cold part of the sample which allows a continuous measurement of the oxygen activity. The experiments showed a fast oxygen migration down the thermal gradient. When the sample is coated with a tight fitting metallic cladding, an extra term has to be added to the heat of transport. This was interpreted as an electrotransport phenomenon. (Auth.)