Phase Stability of Bismuth Lead Antimony Oxide

Publication Title

Solid State Ionics

Publication Date


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phase equilibria, bismuth lead oxide, antimony oxide, powder X-ray diffraction


Chemical Engineering


Phase equilibria in the system (Bi1−xSbx)8Pb5O17 (x=0–0.3) was studied using high temperature X-ray diffraction in combination with differential thermal analysis. Five phases were identified in this system: tetragonal Bi8Pb5O172), tetragonal Bi1.23Pb0.77O2.623), intermediate Φ-phase, body-centred cubic Bi8Pb5O17(β), and orthorhombic Bi3SbO7(χ); the temperatures at which these different phases occurred were thus determined. Of particular interest in relation to undoped Bi8Pb5O17, were the temperature ranges (on heating): below 420°C, pure β2-phase; 420–460°C, coexistence of β2-phase and Φ-phase; 460–590°C, Φ-phase; 590–615°C, a mixture of Φ-phase and β-phase; above 615°C, pure β-phase. On cooling, the high temperature β-phase transfers to the β2-phase in the temperature range 615–590°C. Increasing the Sb concentration, x, in (BixSb1−x)8Pb5O17 caused a decrease in the temperature at which pure β-phase formed on heating. At 10 mol% Sb dopant level, the Φ-phase appears at much lower temperatures than the others. Two hypothetical binary diagrams (of Bi8Pb5O17–Bi3SbO7) were constructed for heating and cooling regimes, respectively, which show the phases present in (BixSb1−x)8Pb5O17 over a range of different Sb concentrations (x=0–0.3) and temperatures (room temperature to 630°C).