Thermogalvanic power and fast ion conduction in δ-Bi2O3 and δ-(Bi2O3)1−x(R2O3)x with R = Y, TbLu

Abstract

The thermogalvanic power E (Seebeck coefficient) of 02-conducting s-Biz03 and 6-(Bi203)1_x(Y203)x has been measured directly as a function of temperature and partial oxygen pressure in N2 -02 mixtures. The E of 6-(Bi 2 3 0 ) ,,.75&03h,.25 with R = Tb-Lu was indirectly determined using an isothermal concentration cell technique. Except for pure 6-Bi20,, the heat of transport is much smaller than the activation energy for 02-conduction for all materials. The vibrational freedom of 02-ions in all L-stabilized materials is reflected in their IR spectra at room temperature. Two prototypes of a thermogalvanic POZ meter were tested.

The electrical conductivity of δ-Bi2O3 stabilized by isovalent rare-earth oxides R2O3

“…One possible explanation would be the existence of a small amount of a second phase (with low conductivity) which could not be detected by X-ray diffraction because of its rather low resolution of 6%. The IR absorption spectra were checked for their sensitivity to a second phase [44] with an even worse result of ~20%. However, semi-micro DTA experiments, with a much better sensitivity did not prove the existence of a significant amount of second phase.…”