| 摘要 |
PURPOSE:To obtain a sensor which suppresses the change of sensitivity and selectivity to and of CO with lapse of time and obviates decrease in the sensitivity to CO owing to the presence of NOx by depositing ruthenium oxide together with the oxide of a specific metal in order to obtain thermal stability to a sintered body consisting of a metallic oxide semiconductor. CONSTITUTION:A circuit having resistors R0, R1, R2 and a power source E and voltmeter V is constituted by using a gaseous CO sensor Rs formed by depositing >=1 kinds among metallic oxides of Ti, Zr, Hf, Th, Ce and La together with the ruthenium oxide on the metallic oxide semiconductor such as SnO2 to the coil part of a platinum-rhodium wire (20mu wire diameter). The concn. of CO is measured from the output of the sensor Rs. The sensor maintains virtually the initial sensitivity to CO without change even if NOx exists and has good stability with lapse of time. The sensor having high reliability is thus obtd. |
