Hydrothermal Synthesis Of (ZrO₂)_1-x(RE₂O₃)_x (RE=Gd, Er, Ho) Nanocrystallites In Basic Media And Electrical Properties Of Their Sinters

(ZrO2)1-x(RE2O3)x (RE = Gd, Er, Ho; x = 0.06, 0.08, 0.10) nanocrystallites with cubic phase were hydrothermally prepared in basic media by co-precipitate precursor. It is discovered that the 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 1450 癈, 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 performances of the hydrogen-air fuel cells based on the ceramics were determined at 800 ~ 1000 . The results show that these sinters are almost pure oxygen conductors with oxide-ionic transport number of 1 in oxygen atmosphere above 800 . The maximum short-circuit current density at 1000 was increased with the increasing amount of dopant and the decreasing pH value of reaction medium.