Low Vacuum Measurement of Zirconia-Based Oxygen Sensor for an Evacuated (Air) System

The cell EMFs of oxygen in an evacuated (air) system (105 ~103Pa) versus atmospheric oxygen were measured from 600℃ to 800℃ by an oxygen concentration cell with a solid electrolyte of yttria stabilized zirconia. The experimental results showed that there is a linear relationship between the cell EMF and the logarithm of residual atmospheric pressure p in an evacuated (air)system. The produced EMF is given by the eqution E = (RT/4F)1n(Pair/p), in which it's slope is close to theoretic value and error less than 5%. The sensibility of measured EMF increases with the pressure decrease and may be suitable for low vacuum measurement.