Characterization of zirconia oxygen sensors with a molten internal reference for low-temperature operation

A miniature zirconia oxygen sensor with a molten internal reference was developed for low-temperature use. As the internal reference, In-In2O3, Sn-SnO2, and Pb-PbO were tested. Sensors with Sn-SnO2 and Pb-PbO worked well at low temperatures near 550 K, and were superior to one with In-In2O3. The sensor with a molten reference responded quickly to temperature changes. An advantage of using a molten reference instead of a solid reference is that the molten reference has good contact with the zirconia electrolyte due to its wettability. (C) 2003 Elsevier Science B.V. All rights reserved.