| ZrO2-8 mol% Y2O3 nanocrystallites with a cubic phase were hydrothermally prepared in basic media, with co-precipitate of Zr(OH)4 and Y(OH)3 from the solutions of ZrOCl2 8H2O and Y(NO3)3 6H2O as precursor. It is discovered that the cubic-phased nanocrystallite size is obviously affected by pH value, temperature and time of hydrothermal reaction. The higher the pH value of reaction medium and the reaction temperature, the larger the nanocrystallite sizes. Green compacts made from the nanopowders can be sintered to above 97% of theoretical density at 1400 ℃, which is 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 with oxide-ionic transport number of 1 in oxygen atmosphere above 800 ℃. |
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