LONG-TERM RELIABILITY OF SENSORS FOR DETECTION OF NITROGEN-OXIDES

In this work, the reliability and reproducibility of tin oxide as sens or material for the detection of nitrogen oxides as well as its behavi our when operating for long periods are studied. The experiments were carried out with thin films (3000 Angstrom) of tin oxide doped with al uminium. The sensors were operating for six months in synthetic air at the constant temperature of 525 K. During this time they were exposed with regularity to nitrogen oxide in order to determine the frequency at which calibration checks should be carried out and the frequency a t which sensors may have to be replaced.