Liquidus Curve Measurements in the ZrO2-MgO System with the Solar Furnace

Abstract

A liquidus curve in the system ZrO2-MgO was investigated by the use of a heliostat type solar furnace. The cooling curves of a composition were obtained by the specular reflection method with a brightness pyrometer. Quenched specimens from the melt were examined with an X-ray technique and a petrographic microscope. Newly found anomalies on the liquidus curve were 7.5, 12.5 and 17.5 mol% MgO compositions. The composition of 12.5 mol% MgO quenched from the melt showed the new cubic-like phase of which optic angle of 2 V equals to −74°C and decomposed easily into monoclinic and tetragonal forms by reheating at 1300°C.