A high-temperature metallic oxide resistive oxygen sensor

Abstract

The efficacy of a resistive thick film of YBa2Cu3Ox on an yttria-stabilized zirconia substrate for monitoring the concentration of oxygen in a gas mixture has been experimentally evaluated over the temperature range 600-680 °C and oxygen concentrations corresponding to a partial pressure from 0.009 to 1 atmosphere. The mixed oxide shows a fast oxygen indiffusion but relatively slow outdiffusion. The sensor resistance decreases quantitatively with a decrease in the gas temperature and an increase in the partial pressure of oxygen. The lower resistance with higher oxygen concentration may be attributed to the increase in the concentration of positive holes in the oxide film, and vice versa. Corresponding to a sensor resistance of R ohms, the oxygen partial pressure (PO2 atm) in a gas mixture at a temperature T K is given by the correlation {A figure is presented}. © 1992.