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 Bi8Pb5O17(β2), tetragonal Bi1.23Pb0.77O2.62(β3), 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).
Solid State Ionics
Du, Yanhai; Sammes, Nigel M.; Tompsett, Geoffrey A.; Zhang, Y. (1999). Phase Stability of Bismuth Lead Antimony Oxide. Solid State Ionics 117(3-4) 291-299. doi: 10.1016/S0167-2738(98)00410-X. Retrieved from https://oaks.kent.edu/caestpubs/20