Oxygen sensors

Abstract
Oxygen sensors are based on oxygen ion conductors (e.g., doped ZrO2) or on semiconductors (e.g., TiO2 Nb2O5). The principles, materials, and performance of both types are covered. Recent advances include miniaturization, lower temperature operation, and use of planar technology for fabrication to decrease cost and improve reliability. Applications in automotive, furnace operation, and iron and steel industry are reviewed, which indicate that sensor technology is a mature field and is poised to expand further.