On the phase relations and the electrical conductivity in the system ZrO2Sc2O3

Abstract Phase relations in the ZrO 2 Sc 2 O 3 system have been investigated by the methods of high-temperature X-ray analysis, dilatometry, differential thermal analysis, and electrical conductivity measurements in the composition range 3–40 mol % Sc 2 O 3 and the temperature range 20–2000°C. The phase diagram has been constructed in its subsolidus regions. Existence regions have been refined for three known compounds, Sc 2 Zr 7 O 17 , Sc 2 Zr 5 O 13 , and Sc 4 Zr 3 O 12 , and the region corresponding to high-temperature, cubic, fluorite-type solid solutions has been established. The character of the thermal dependence of the electrical conductivity for the compositions studied agrees with the phase transformations. The maximum value of the electrical conductivity at 1200°C was observed for the composition 7.5–9 mol % Sc 2 O 3 . With increasing temperature, in the field of the high-temperature solid solutions, there occurs a broadening of this maximum and a lateral displacement to higher content of scandium oxide.