Impedance Analysis on Solid Electrolyte Oxygen Sensor
Li Guangqiang ;Xu Xiuguang(Non-ferrous Metallurgy Dopartment, The Northeastern University Shenyang 110006 china)
The impedancce spectra of YSZ solid electrolyte oxygen sensor used in atmosphere monitoring of the fiuidizing-bed roasting furnace in sulphuric acid factory were measured by a frequency response analyser(FRA) in air at 680℃. The frequency range of the measurement was 0.01 to 1MHz. The measured impedance spectra were analysed by a new developed equivalent circuit. The LEVM impedance analysing program was used for the complex nonlinear least square fitting(CNLS). The equivalent circuit parameters corresponding to the impedance spectra were obtained. It is indicated that both the property of the bulk resistance of the solid electrolyte and the electrode are different between the new and the used oxygen sensors, but the electrode impedance of the tised oxygen sensor was much higher than that of the new one. The resistance increase of the used oxgen sensor is due to the electrode impedance increasing. The service life of the oxygen sensor depends on the service life of the electrode.