Long-term stability of miniaturized potentiometric CO2-sensors in thick-film technology

A potentiometric thick-film CO2-Sensor based on the electrochemical cell: O2, CO2, Na2CO3/Au(Doppelstrich)Na-beta/beta''-Al2O3(Doppelstrich)Na2Si2O5/Au, O2, (CO2) was investigated regarding the long-term stability of the solid electrolyte and the influence of preheating conditions. Na-beta/beta''-Al2O3 (NBA) was deposited by means of two different techniques following in a porous and a compact NBA layer, resulting in different stability behavior of the sensor.