NEW ELECTROCHEMICAL SENSORS FOR OXYGEN DETERMINATION

Oxygen sensors which can operate in wider oxygen pressure and temperature ranges than currently used stabilized zirconia-based oxygen sensors are described. Strontium fluoride-lanthanum fluoride solid solution electrolytes have higher conductivities than zirconia and, when dispersed with an oxide phase, can operate at lower temperatures and oxygen partial pressures than zirconia-based oxygen sensors. Other potential electrolyte materials for low oxygen partial pressure applications are some very stable perovskite oxides, which are pure oxide-ion conductors at lower oxygen partial pressures than stabilized zirconia. In high-temperature aggressive environments, the lifetime of zirconia-based oxygen sensors can be extended through the use of a non-isothermal sensor, in which the temperature of the reference electrode is reduced.