Phase relations at 1500 degrees C in the ternary system ZrO2-Gd2O3-TiO2

Phase relations at 1500 degreesC in the ternary system ZrO2-Gd2O3-TiO2 have been determined by the powder X-ray diffraction of samples prepared by sta ndard solid state reaction. A large area of this ternary oxide system cente red on the Gd2Ti2O7-Gd2Zr2O7 join was shown to exhibit the pyrochlore and d efect fluorite structures. The pyrochlore structure was observed for stoich iometries as far from the ideal M4O7 as M4O6.7 and M4O7.4, although the deg ree of disorder seemed much higher at these stoichiometries. On further dev iation from the ideal M4O7 stoichiometry a smooth transition to fluorite av erage structure was observed for Zr-rich compositions. None of the other bi nary phases were observed to show significant extent of solid solution into the ternary region. (C) 2001 Academic Press.