PRODUCTION OF SENSOR ELEMENT FOR GAS SENSOR

摘要

PURPOSE:To selectively detect NO by forming a sensor element which has a perovskite structure and consists of composite oxide having specific surface area of one to several tens m<2>/g in a specified stage. CONSTITUTION:Firstly nitrate of metal constituting composite oxide and citric acid are prepared and a mixed aq. soln. is produced. Then this mixed aq. soln. is vacuumized and dried in a vessel such as a flask and the bubble body of citric acid complex is formed. Furthermore this citric acid complex is dried and thereafter cracked in vacuum, the atmosphere or the inert gas. This cracked substance is cooled and thereafter calcined at 400-500 deg.C in the atmosphere. Composite oxide having a perovskite structure is obtained by intactly roasting the cracked substance at 600-950 deg.C or grinding it or compressing the powder and thereafter roasting this powder at the same temp. As salt of metal constituting the composite oxide, acetate may be utilized. The composite oxide which is produced in such a way and constituted of the perovskite structure has specific surface area of one of several tens m<2>/g and can absorb large amounts of NO.