A METHOD OF PRODUCING A STANNIC OXIDE TYPE GAS-DETECTING DEVICE

摘要

An improved thick film stannic oxide sensor SN is disclosed whereby the sensitivity of the sensor to CO is enhanced by the addition of a rare earth oxide (e.g., lanthanum oxide unlike ThO2 in prior art) to the sensor composition; the catalytic reactivity of the sensor, when contacted by a gas containing a reducing constituent, i.e., H2 or CO, and oxygen, is enhanced by employing RUCl3 or PtCl2 in predetermined quantities as a catalyst which is uniformly distributed in the stannic oxide (powder) during production. The amount of the reducing constituent causes a change in the sensor resistivity measured by the current flowing in a local monitoring circuit using power supply (PS) and resistance (R). A potential drop measured by (MC) across the resistance (R) is indicative of the reducingconstituent content.