Z1O2-8 mol% Y_2O_3 nanocrystallites with a cubic phase were hydrotheimally prepared in basic media, with Zr(01-1)4 and Y(OH)_3 co- precipitated from the solutions of ZrOCl_2·8H_2O and Y(NO_3)_3·6H_2O as precursor, It was discovered that the cubic-phased nanocrystallite size was obviously affected by pH value, temperature and time of hydrothermal reaction. The higher the pH value of the reaction medium and the reaction temperature, the larger the nanocrystallite size. Green compacts made from the nanopowders can be sintered to above 97 % of theoretical density at 1400 ℃, about 150 ℃ lower than that for traditional high temperature solid state reaction. The oxygen ion conduction properties of these sinters were investigated by means of oxygen concentration cell and oxygen pump (electrochemical oxygen permeation) at 600 -1000 ℃. The results show that these sinters are almost pure oxygen conductors in oxygen atmosphere above 800 ℃.

Key words: ZIRCONIUM OXIDE, YTTRIUM OXIDE, NANOPHASE MATERIALS, SOLID ELECTROLYTE, HYDRO-THERMAL REACTION, CERAMICS, CLINKERING, ELECTRICAL CONDUCTIVITY