| 摘要 |
The invention concerns the production of a piezo-electric absorption moisture-content indicating sensor for a piezo-electric oscillating silica cut (1), equipped with metal electrodes (2a, 3a), which is applied with a layer (10, 11) of pure aluminium Al at a thickness of 0.5 to 10 μm, then a moisture sensitive layer (12, 13) is formed of porous oxyaluminum hydroxide Al0(OH) with a thickness of 0.3 to 0.5 μm. The moisture sensitive layer (12, 13) of porous oxyaluminum hydroxide Al0(OH) is prepared by surface hydration of the layer (10, 11) of pure aluminium Al in boiling redistilled or deionised water and then the moisture sensitive layer (12, 13) is passivated by wetting in an aqueous solution of sodium dihydrogen phosphate NaH2P04.2H20 at a concentration of 0.01 to 1 mol at a temperature of 35 to 100 degrees C for a period of 5 to 60 minutes. Then it is tempered in a gaseous environment chemically inert towards the layer (12, 13) for a period from 2 to 24 hours at a temperature of 70 to 110 degrees C.<IMAGE>
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