PHASE STABILITY AND CONDUCTIVITY OF δ-Bi2O3 WITH MIXTURE OF YTTRIUM AND YTTERBIUM OXIDES

In this research Bi2O3 was doped with mixtures of 8, 10, 12 and 18 mol% of Y2O3 and Yb2O3 in order to stabilize the δ-Bi2O3 phase using solid state reaction technique. Experimentalsamples were fabricated by isostatic pressing and sintering at 850sC for 24 h. X-ray diffraction analysis detected cubic phase (δ-Bi2O3) as the sole stable crystalline phase in samples including 12 and 18 mol% of Y2O3 and Yb2O3. The tetragonal phase was also observed in samples with 8 and10% mol additives. X-ray diffraction analyses on aged samples at 600 oC with 12 mol% additivesrevealed that the δ-Bi2O3 phase was transformed to the tetragonal polymorph form. Results of ionicconductivity measurements showed that samples with 12 mol% additives (88 mol% Bi2O3, 8 mol% Y2O3 and 4 mol% Yb2O3) had a higher ionic conductivity than the other samples.

کلیدواژه ها:

Powders-solid state reaction ، X-ray methods ، Electrical conductivity ، Bismuth oxide/ Fuel cells