PHASE-EQUILIBRIA IN THE BI-RICH PART OF THE BI, MO O SYSTEM/

The phase diagram of the Bi2O3-MoO3 system was investigated with combi ned impedance spectroscopy, differential thermal analysis and X-ray po wder diffraction measurements in the composition range 0 less than or equal to x(Mo) less than or equal to 0.156. The samples were prepared by high temperature solid state reaction to account for the high react ivity of Bi-rich melts and the sluggishness of the solid-state equilib ria. At high temperatures, a fluorite-like solid solution, delta, is s table over the whole composition range, and is separated by the stabil ity field of the liquid phase by a lens-shaped biphasic region. Below the delta phase, two compounds are stable down to room temperature (rt ) at the compositions x(Mo) = 0.067 (m = 14) (C1) and x(Mo) = 0.156 (m similar to 5.4) (C2) (m = Bi/Mo). The eutectoid between pure alpha-Bi 2O3 and C1 is at x(Mo) similar to 0.016 at T similar to 725 degrees C, whereas the eutectoid between C1 and C2 is at x(Mo) similar to 0.091 at T-800 degrees C.