A method of improving response and recovery time of semiconducting tin oxide based gas sensors in thick film form for detection of combustible gases

xide based gas sensors in thick film form for detection of combustible gases like methane, liquefied petroleum gas (LPG), propane, compressed natural gas (CNG), and produced semiconducting tin oxide based gas sensors in thick film form, are disclosed. The improved gas sensors are made by coating pre-cleaned and electroded tubular alumina substrates with a sensor coating comprising tin dioxide (SnO2), antimony oxide (Sb2O3) in the range of 0.2-0.3 weight% with respect to SnO2 and palladium in the range of 5-10 weight% with respect to SnO2 and alumina gel equivalent to 0.05 weight% alumina with respect to SnO2 along with a gas forming agent such as ammonium nitrate in the range of 0.25-2 weight% with respect to SnO2 batch composition, vacuum drying and curing the sensor coating at a temperature in the range of 600-700 degrees C for a time in the range of 30 minutes to 2 hours at a heating rate in the range of 50-75 degrees C/h so as to get coating microstructure having controlled cracks. The response and recovery time of the thick film sensors prepared by this method are around 15 seconds and 1 minute 15 seconds, respectively, which are acceptable for real-life applications of the sensors. The method also imparts good adherence of the coating with the substrates. The sensors made by the method are highly sensitive towards the combustible gases to be detected. The processing steps of the fabrication of such sensors are also simple and cost effective.