| 摘要 |
PURPOSE:To obtain a gas sensor having excellent sensitivity to combustible gas and excellent instability and durability, by providing electrodes to a metal oxide semiconductive sintered body consisting of two layers which are the same in a composition but different in density. CONSTITUTION:As a metal oxide semiconductor, SnO2, ZnO, Fe2O3, TiO2 or Cr2O3 to each of which no catalyst is added at all are desired. when SnO2 is used as metal oxide, tin oxalate is thermally decomposed and calcined at 800 deg.C to form SnO2 having a particle size of about 0.1mum and the formed SnO2 is molded under pressure while Pt lines are embedded in the molded one to form electrodes 1, 2 and the whole is subjected to primary baking at 1,000-1,500 deg.C to form a first layer 3. An org. solvent in which SnO2 with a particle, size of 0.1mum formed by calcination is dispersed is applied to said first layer 3 and subjected to secondary baking at a temp. ranging from 600 deg.C to the primary baking temp. to form a second layer 4. The obtained element is used at a temp. of 100-600 deg.C. |
