JPS562549A - Manufacture of sensor for detecting concentration of oxygen - Google Patents

Abstract

PURPOSE: To improve sensitivity and durability by forming catalyst metal electrodes by reducing and thermally decomposing a solution of catalyst metal salt, applied on the surface of a sinter of an oxygen ion conductive solid electrolyte, and further by forming a protective electrode by thermally decomposing in an irreducible atmosphere the above-mentioned solution applied on those electrodes.

CONSTITUTION: On both sides of sinter 9 of an oxygen ion conductive solid electrolyte consisting of 92mol% ZrO₂ and 8mol% Y₂O₃, a solution of catalyst metal salt such as H₂PtCl₆ is applied and, after reduced at the normal temperature in an H₂ atmosphere, baked in an H₂ atmospheric furnace at about 600°C to form catalyst metal electrodes 10 and 11. The quantity of sticking catalyst metal should be between 0.1 and 10cmg/cm². On electrodes 10 and 11, the above-mentioned catalyst metal salt solution is applied and baked at about 600°C in an irreducible atmosphere (N₂, air, Ar, etc.) to form a protective electrode. The quantity of sticking catalyst metal of the protective electrode should be between 1 and 30mg/cm². On exhaust- gas-side electrode 10, overcoat layer 12 of ceramics, etc., is formed by a flame coating method, etc., so as to prevent electrode 10 from deteriorating.

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