| 摘要 |
PROBLEM TO BE SOLVED: To obtain a highly sensitive gas detecting element by mixing colloidal silica and low-molecular-weight polyethylene glycol in stannic oxide power and burning an element film formed by applying dried stannic oxide paste to a substrate to be a sensitive film. SOLUTION: Raw material powder of stannic oxide is calcined at approximately 150-700 deg.C for approximately 2-10 hours and is ground into powder of average particle diameters of approximately 0.1-1μm in a ball mill. This powder is dispersed in a slurry form and predetermined amounts of colloidal silica and low-molecular-weight polyethylene glycol are added to it in a container for vacuum freeze-drying and mixed in a liquid phase. Then, it is freeze-dried in a vacuum to obtain paste of a viscosity (approximately 50-200 pascal second) on the basis of the added amount of polyethylene glycol. A masking plate is overlaid on a one-piece substrate formed of a plurality of continuously arranged substrates 2 on which electrodes 5 and a heater 3 are laminated in advance, the paste is applied by a squeezee, and then the masking plate is removed. The thickness of the film is approximately 5-50μm. The one-piece substrate is burned at approximately 500-700 deg.C and divided into pieces to obtain a plurality of homogenous elements 1.
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