Zirconium DIOxide Technique
OPSIS zirconia oxygen analyser consists of a zirconia sensor. It makes use of the oxygen ion conductivity of solid electrolytes composed mainly of zirconia at high temperatures.
If electrodes of platinum or similar materials are attached to both faces of a solid electrolyte and the faces are on the conditions of different oxygen partial pressures, an electrochemical reaction causes an electromotive force between both electrodes.
Microscopically, it is assumed that electrochemical reactions occur at the (three phase) interface among a solid electrolyte, electrode and oxygen.