| Research Abstract |
In order to survey good electrodes for zirconia oxygen sensors, electrode characteristics of several noble metals (Pt, Rh, Pd, Au and Ag), several rare earth oxides (Tb_4O_7, CeO_2, Pr_6O_<11> and Ca-doped lanthanum manganite (La_<1-x>Ca_xMnO_3 : X=0, 0.1, 0.2) were investigated using the complex impedance spectroscopy in the temperature range, 200-1400 ^ﾟC and in the oxygen pressure range, 10^<-6>-1 atm. At high temperatures, Pt has good electrode characteristics, and, on the other hand, at low temperatures, Ag has excellent electrode characteristics. Rh and Pd acted as oxide electrodes at high oxygey pressures or ta low temperatures. Pr_6O_<11> showed the best electrode property of the rare earth oxides examined. Electrode characteristics of Pr_6O_<11> and its bonding property with yttria-stabilized zirconia (YSZ) was improved by adding Pt powder. Electrode characteristics of La_<1-x>Ca_xMnO_3 were improved with increasing Ca concentration, because of low reactivity with YSZ.
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