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

Authors

Ceramic, Material and Energy Research Center(MERC)

Abstract

In this research Bi2O3 was doped with mixtures of 8, 10, 12 and 18 mol % of Y2O3 and Yb2O3 to stabilizing the δ-Bi2O3 phase using solid state reaction technique. Experimental samples were fabricated by isostatic pressing and sintering at 850 °C 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 and 10% mol additives.  X-ray diffraction analyses on aged samples at 600 oC with 12 mol % additives revealed that the δ-Bi2O3 phase was transformed to the tetragonal polymorph form.  Results of ionic conductivity 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. 

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