JPH05164731A - Manufacture of oxygen sensor - Google Patents

Abstract

PURPOSE:To manufacture a solid electrolyte oxygen sensor capable of developing fast response. CONSTITUTION:A porous platinum electrode 2, a stabilized zirconia layer 3 and a porous platinum electrode 4 are successively formed on an Ni substrate 1 by an in-line continuous sputtering method. Subsequently, paste consisting of an alumina powder, a Na2O/B2O3/SiO2 type glass powder, an acrylic resin and dimethylformamide is applied thereto and baked to form a porous ceramics layer 5. Finally, the part of the Ni substrate 1 is etched and removed by an equal amount liquid mixture of nitric acid, acetic acid and acetone to obtain a solid electrolyte oxygen sensor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an oxygen sensor. More specifically, it relates to a method for manufacturing a solid electrolyte oxygen sensor.

[0002]

_2. Description of the Related Art Conventional solid oxide oxygen sensors are, for example, stabilized zirconia (zirconia ZrO _{2 in} which alkali metal oxides such as CaO, Y ₂ O ₃ and ThO ₂ and rare earth metal oxides are solid-dissolved). Form porous platinum electrodes on both sides of the sintered body of
Further, it is manufactured by forming a porous ceramic layer on one side thereof.

In this case, the response speed of the oxygen sensor is governed by the thickness of the stabilized zirconia layer, in other words, by the gas diffusion rate controlling. Therefore, the smaller the thickness of the stabilized zirconia layer, the faster the response speed, but in the method of forming platinum electrodes on both sides of the already formed stabilized zirconia, the thickness of the stabilized zirconia layer is reduced. Is about 50 μm at most, and the response time in this case is about 0.2 seconds. Therefore, it is the current situation that it cannot be adequately applied to applications such as engine control that require a higher speed response.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a solid electrolyte oxygen sensor which can exhibit high-speed response.

[0005]

The object of the present invention is as follows.
This is achieved by sequentially forming a porous platinum electrode, a stabilized zirconia layer, a porous platinum electrode and a porous ceramic layer covering these on a metal substrate, and then etching away the metal substrate to produce an oxygen sensor. ..

FIG. 1 shows one embodiment of the method of the present invention, in which a porous platinum electrode 2, a stabilized zirconia layer 3, a porous platinum electrode 4 and a porous layer covering them are provided on a metal substrate 1. After the ceramic layers 5 are sequentially formed, the portion of the metal substrate 1 is removed by etching, and the contacts 6, 6'are provided on both porous platinum electrodes, whereby the solid electrolyte oxygen sensor is manufactured.

As the metal substrate, a substrate made of Ni, Cu, Al or the like that can be wet-etched in the final step is used. A porous platinum electrode is formed by vapor deposition or sputtering to a film thickness of about 10 nm, or by covering with a mesh-shaped metal mask and then vapor-depositing or sputtering to form an arbitrary thickness. And the like.

The formation of the stabilized zirconia layer is carried out with about 5-10 mol% CaO, about 9-15 mol% MgO or about 6-8 mol% with respect to ZrO ₂ .
It is carried out using a mixture of powders of mol% Y ₂ O ₃ . Specifically, a vapor deposition method using pellets or powders of the above mixture, an ion plating method, a method of sputtering a fired mixture of the above mixture as a target, or a method of simultaneously sputtering each individual target, etc. Is done by applying.

The formation of the porous platinum electrode on the stabilized zirconia layer is carried out in the same manner as described above. The porous ceramics layer covering these is made of low melting point glass powder, ceramics powder, etc. and acrylic resin, polyester resin, polyurethane resin, ethyl cellulose, cellulose.
A polymer powder such as suacetate butyrate was dispersed in an organic solvent such as xylene, ketones, glycol ethers, glycol esters and alkylamides to form a paste, which was applied. It is formed by post-baking.

The etching of the metal substrate after these are sequentially formed depends on the type of the substrate metal used. For example, in the case of nickel, an equal volume mixture of nitric acid-acetic acid-acetone is used as an etching solution. Is done.

In use as an oxygen sensor, a change in voltage is measured by a lead wire taken out from a porous platinum electrode formed on both sides of the stabilized zirconia layer.

[0012]

EFFECTS OF THE INVENTION A metal that can be removed by etching is used for a substrate, and a porous platinum electrode, a stabilized zirconia layer, a porous platinum electrode, and a porous ceramic layer covering these are sequentially formed on the metal substrate. By etching away, the stabilized zirconia layer can be thinned, thereby improving the responsiveness of the solid electrolyte oxygen sensor.

[0013]

EXAMPLES The present invention will now be described with reference to examples.

Example A mixture of a porous platinum electrode (film thickness 100Å) and a stabilized zirconia layer (7 mol% Y ₂ O _{3 based on} ZrO ₂ ) was sintered on a nickel substrate by an in-line continuous sputtering method. By sputtering the target, the film thickness 2μ
m)) and a porous platinum electrode (film thickness 100 Å) are formed, and then a paste consisting of alumina powder, Na ₂ O ・ B ₂ O ₃・ SiO ₂ glass powder, acrylic resin and dimethylformamide is placed there. After coating and drying, it was baked at 650 ° C. to form a porous ceramic layer. Finally,
Etching with an equal volume mixture of nitric acid-acetic acid-acetone was performed to remove the nickel substrate layer.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the method of the present invention.

[Explanation of symbols]

 1 Metal Substrate 2 Porous Platinum Electrode 3 Stabilized Zirconia Layer 4 Porous Platinum Electrode 5 Porous Ceramic Layer

Claims (1)

[Claims] 1. A metal substrate is formed by sequentially forming a porous platinum electrode, a stabilized zirconia layer, a porous platinum electrode, and a porous ceramic layer covering these, and then etching the metal substrate. Oxygen sensor manufacturing method.