Performance of oxygen sensor in lead–bismuth at high temperature

Performance of yttria-stabilized zirconia solid electrolyte oxygen sensor with a reference electrode of Bi/Bi2O3 was investigated. The oxygen sensor was tested in alumina vessel in order to prevent generating of impurities. The oxygen potential in the melt was controlled by injecting steam–hydrogen gas mixture (PH2/PH2O)(PH2/PH2O) into stagnant LBE. The electromotive force (EMF) of the sensor was compared with the theoretical EMF derived from the Nernst equation at various LBE temperatures (550–700 °C). The influences of various injection gas temperatures (200–500 °C) on the sensor output were also investigated. It was found that the sensor signals of the oxygen potential in LBE have not been affected by the injection gas temperature. The results also showed that the measured EMFs were in good agreement with the theoretical values of the EMF. The material aspects were investigated as well. The SEM (Scanning Electron Microscope) devices were used to analyze the cross-section of oxygen sensors after the exposition to LBE at 700 °C for 1000 h. The SEM micrograph showed that the yttria-stabilized zirconia solid electrolyte had an excellent corrosion resistance to the high temperature LBE as the working fluid and high temperature bismuth as the reference fluid.