A SrF2-based oxygen sensor operative at low temperature

Potentiometric disk type oxygen sensors monitoring in low temperatures (200-500 degrees C) were fabricated using SrF2 and their sensing characteristics were investigated. The disk type oxygen sensors consist of a reference electrode: Air (O-2)/Pt, a solid electrolyte SrF2 and a sensing Pt electrode. The correlation between the electromotive force(EMF) and oxygen partial pressure at various temperatures between 200 and 500 degrees C was obtained. The experimental results were found to follow the Nernst equation in the test range of 0.1-100% oxygen partial pressure. The sensor element of the disk type showed an EMF change of 60 mV for an oxygen concentration change of 1-10% at a device temperature of 300 degrees C. The sensor with Ni/NiO reference electrode showed an EMF change of 55 mV change for an oxygen concentration change of 0.1-10% at the same temperature. (C) 1998 Elsevier Science S.A. All rights reserved.