| 摘要 |
A process for fabricating an oxygen sensor element of the type of a concentration cell in the form of a layer structure of relatively thin layers. The first step of the process consists in the production of a sheet of a ceramic screening layer which serves as a substrate. Subsequently, an internal or reference electrode layer, a solid-electrolyte layer which conducts oxygen ions, and an external or measuring-electrode (working-electrode) layer is generated, which is made porous by sintering an electron-conducting powder which is applied to the solid-electrolyte layer face in the form of a paste. In order to improve the response of the oxygen sensor element, an additional measuring-electrode layer consisting of metal, such as platinum, and preferably not being thicker than 0.5 micron, is generated on the sintered measuring-electrode layer by physical vapour deposition techniques such as spraying, ion-plating or vacuum evaporation, while using a mask. The mask has an orifice, by virtue of which only the outer faces of the sintered measuring-electrode layer are exposed. In order to enhance the adhesive strength of the deposited measuring-electrode layer, a conducting ceramic-metal mixture is employed as the material of the sintered measuring-electrode layer.
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