JPS6034064B2 - Stacked membrane structure oxygen sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laminated membrane structure oxygen sensor using an oxygen ion conductive solid electrolyte layer, and more specifically, a corneal membrane layer, a first electrode layer, an oxygen ion conductive solid electrolyte layer, A 0th electrode layer is sequentially laminated, at least one of the diaphragm layer and the oxygen ion-conducting collective electrolyte layer is made gas permeable, and the potential difference generated between the two electrodes is measured to increase the oxygen concentration in the fluid. The present invention relates to a laminated membrane structure oxygen sensor suitable for detecting oxygen concentration in automobile engine exhaust gas.

FIG. 1 is a schematic cross-sectional view of a secondary laminated waist structure oxygen sensor; a diaphragm layer 1 that maintains strength as a structural base;
A first electrode layer 2, a gas permeable oxygen ion conductive solid electrolyte layer 3, and a zeroth electrode layer 4 are sequentially laminated, and both electrode layers 2,
In order to measure the potential difference occurring between the 0th electrode layer 4, a voltage measuring device 6 is connected via a lead wire 5, and the surface of the 0th electrode layer 4 is further covered with a protective layer 7.

In an oxygen sensor having such a structure, when the gas to be measured changes from a rich side to a lean side, or conversely from a lean side to a rich side, the 0th electrode layer 4 and the oxygen ion conductive solid electrolyte layer 3 are When reaching the first electrode layer 2 through the solid electrolyte layer 3, a difference in oxygen partial pressure is generated between the first electrode layer 2 and the zeroth electrode layer 4 for a very short time required for passing through the solid electrolyte layer 3. Therefore, an output voltage (see FIG. 12) is generated based on this difference in oxygen partial pressure. In this case, generally AI203 (alumina) is used for the corneal membrane layer 1 as a substrate.
2 of Y203-Z (yttria stabilized zirconia) or Ca○-Z is used for the solid electrolyte layer 3.
r02 (Lucia stabilized zirconia) is often used, and as the protective layer 7, Ca○-Zr02 (calcium zirconate), N203 (alumina), etc. are often used.

In such a structure, the interface between the diaphragm layer 1 and the first electrode layer 2 is a bonding surface between metal and ceramic, but this bonding surface is not a chemical bonding but a physical or mechanical bonding surface. It becomes.

Therefore, at such a joint surface, the bonding force between the two layers is small due to the difference in the thermal expansion coefficients of the materials in contact with each other, and this is especially true in low and high temperature conditions, such as when detecting the oxygen concentration in automobile engine exhaust gas. In a usage environment in which it is repeatedly installed in a high-temperature, high-speed fluid, there is a problem in that the two layers tend to separate or peel off at the bonding interface, resulting in poor durability. FIG. 2 is a schematic cross-sectional view of an oxygen sensor attempted to solve the above-mentioned drawbacks, and the first electrode layer 8 has a lattice shape with through holes 8a.

Therefore, the bonding interface between the corneal layer 1 and the first electrode layer 8 is not only bonded only by metal and ceramics, but also by each through hole 8.
Since the ceramics are also bonded to each other through a, the occurrence of problems such as separation or peeling at the interface between the diaphragm layer 1 and the first electrode layer 8 can be significantly prevented compared to the conventional method. Although such attempts can produce some results, the present inventors have continued to conduct research for further improvements. An object of the present invention is to eliminate the drawbacks of the prior art described above, prevent separation or peeling at the bonding interface between the diaphragm layer and the first electrode layer in a laminated membrane structure oxygen sensor, and improve durability. The goal is to make it excellent.

In the present invention, a diaphragm layer, a first electrode layer, an oxygen ion conductive solid electrolyte layer, and a 0th electrode layer are sequentially laminated, and at least one of the diaphragm layer and the oxygen ion conductive collective electrolyte layer is made gas permeable. In the stacked membrane structure oxygen sensor, the zeroth electrode layer is made to be in contact with the gas to be measured, and the potential difference generated between the two electrode layers is measured. It is characterized in that an oxygen ion conductive solid electrolyte layer having basically the same composition as the solid electrolyte layer is provided between them, and preferably the five layers are laminated in an unfired state and formed by simultaneous firing, and Desirably, the second electrode layer is made contactable with the gas to be measured via at least a protective layer formed on the surface of the D electrode layer, and preferably the six layers are laminated in an unfired state and formed by simultaneous firing. It is characterized by

Hereinafter, the present invention will be explained in detail based on examples.

FIG. 3 is a schematic cross-sectional view of a laminated membrane structure oxygen sensor according to an embodiment of the present invention, in which an oxygen ion conductive solid electrolyte layer 19 is provided on a diaphragm layer 11 that maintains strength as a structural base. The first electrode layer 12, the gas-permeable oxygen ion conductive solid electrolyte layer 13, and the second electrode layer 14 are sequentially seeded, and a lead wire 15 is connected to measure the potential difference generated between the two electrode layers 12 and 14. A voltage measuring device 16 is connected through the protective layer 17 and the surface of the second electrode layer 14 is covered with a protective layer 17 so that the second electrode layer 14 can come into contact with the gas to be measured through the protective layer 17. It has a similar structure.

In the oxygen sensor having such a structure, when the gas to be measured changes from a rich side to a lean side or from a lean side to a rich side, the 0th electrode layer 14 and the oxygen ion conductive solid electrolyte layer 13 through the first electrode layer 1
2, a difference in oxygen partial pressure occurs between the first electrode layer 12 and the second electrode layer 14 for a very short period of time required for the oxygen to pass through the solid electrolyte layer 13. Based on the pressure difference, an output voltage as shown in FIG. 12 is generated. FIG. 4 shows another embodiment of the present invention, in which an oxygen ion conductive solid electrolyte layer 19 is placed on a diaphragm layer 11 that maintains strength as a mechanical base, and a lattice-shaped first layer having through holes 18a is provided. The electrode layer 18, the gas-permeable oxygen ion conductive solid electrolyte layer 13, the 0th electrode layer 14, and the protective layer 17 are laminated in this order, and a voltage measuring device 16 is connected between the electrode layers 18 and 14 via a lead wire 15. It forms a connected structure.

In this case as well, output voltage characteristics similar to those shown in FIG. 12 can be obtained. 3 and 4, the oxygen ion conductive solid electrolyte layer 13 is gas impermeable, and the diaphragm layer and the oxygen ion conductive solid electrolyte layer 19 are gas impermeable.
In the case where the capacitor is gas permeable, output voltage characteristics as shown in FIG. 12 can be similarly obtained. FIG. 5 shows still another embodiment of the present invention, in which a diaphragm layer 11 that maintains strength as a structural base, an oxygen ion conductive solid electrolyte layer 19,
A lattice-shaped first electrode layer 18 having through holes 18a, a gas permeable oxygen ion conductive solid electrolyte layer 13, and a zeroth electrode layer 14
and a protective layer 17 are sequentially laminated, and a voltage measuring device 1 for measuring potential difference is connected through a lead wire 15 between both electrode layers 18 and 14.
6, and the first electrode layer 18 and the D-th electrode layer 14
A DC power supply device 30 that causes the movement of oxygen ions through the solid electrolyte layer 13 is connected between the solid electrolyte layer 13 and the solid electrolyte layer 13.

At this time, the connection polarity of the DC power supply device 30 is changed to, for example, the 0th
The negative side is connected to the electrode layer 14 and the first electrode layer 1
By connecting the positive side to 8, the solid electrolyte layer 1
3 from the 0th electrode layer 14 side to the first electrode layer 18 side, oxygen molecules generated in the first electrode layer 18 portion diffuse through the collective electrolyte layer 13, and the inflow of oxygen ions and oxygen By stabilizing the oxygen partial pressure at the interface between the solid electrolyte layer 13 and the first electrode layer 18 at a high state when the diffusion of molecules is balanced, and thereby generating an electromotive force on the fuel excess side than the stoichiometric air-fuel ratio. The characteristics shown in FIG. 13 are obtained.

Furthermore, if the polarity of the connection of the DC power supply device 30 to the polar layers 14 and 18 is reversed, a characteristic in which a high output voltage is generated on the lean side, contrary to that shown in FIG. 13, can be obtained.
Similar characteristics can also be obtained when the diaphragm layer 11 and the solid electrolyte layer 19 are gas permeable. FIG. 6 shows still another embodiment of the present invention, in which a heating conductor layer 31 is provided within a diaphragm layer 11 that maintains strength as a structural base, and a solid electrolyte layer 19 is provided on this diaphragm layer 11. , through hole 18a
It has a structure in which a lattice-shaped first electrode layer 18, a solid electrolyte layer 13, a zeroth electrode layer 14, and a protective layer 17 are sequentially laminated.

In this way, by providing the heating conductor layer 31 and stabilizing the temperature of the solid electrolyte layer 13 at a high temperature, for example, around 500 to 70,000, the drawback of the solid electrolyte that the oxygen ion conductivity is low at low temperatures can be compensated for. In particular, when detecting the oxygen concentration in the exhaust gas of an automobile engine, it can be performed satisfactorily even in a low temperature state at the time of starting.
As shown in each of the above embodiments, the collective electrolyte layer 1 is arranged between the diaphragm layer 11 and the first electrode layers 12, 18 so as to be in direct contact with the corneal membrane layer 11 and the first electrode layers 12, 18.
9, the first electrode layers 12 and 18 are surrounded by both solid electrolyte layers 13 and 19. By the way, in the conventional structure shown in FIGS. 1 and 2, the first electrode layers 2 and 8 are in contact with the diaphragm layer 1 on their lower surfaces, and in contact with the solid electrolyte layer 3 on their upper surfaces. Since the first electrode layers 2 and 8 are surrounded by different materials, there is a difference in thermal expansion coefficient between the upper and lower surfaces of the first electrode layers 2 and 8, which induces separation or peeling of the first electrode layers 2 and 8.

In contrast, in the present invention, the first electrode layer 12,
18 are both solid electrolyte layers 13 having basically the same component system,
19, the first electrode layer 12,
There is no longer a large difference in coefficient of thermal expansion between the upper and lower surfaces of the electrode layer 18, and even if the oxygen sensor becomes hot during use and thermal expansion occurs in each layer, the first electrode layers 11 and 18 will receive a uniform force. Therefore, the first electrode layers 12, 18
Do not apply excessive force to the

Therefore, separation or peeling of the first electrode layers 12 and 18 can be prevented, and durability can be improved. On the other hand, the diaphragm layer 11 and the solid electrolyte layer 19
At the bonding interface, both layers are simultaneously fired at high temperature to cause mutual diffusion, thereby increasing the bonding strength of both layers.

In this case, since the area of the bonding interface between the diaphragm layer 11 and the solid electrolyte layer 19 is greatly expanded compared to the conventional one, the bonding strength can be further increased. Furthermore, the bonding interface between the solid electrolyte layers 13 and 19 has basically the same composition, and even if the ratio of the stabilizer is slightly different or the stabilizer itself is different, the basic composition is the same. Therefore, the effect on the coefficient of thermal expansion is very small, and the bonding strength between the two can be greatly increased by sintering at high temperatures after lamination, so both solid electrolyte layers 13, 19 remain strong even after repeated use at high and low temperatures. It is possible to avoid the occurrence of separation or peeling between the solid electrolyte layers 13, 19, and at the same time, it is possible to almost eliminate the occurrence of problems such as separation or peeling of the first electrode layers 12, 18 from the bonding interface with the solid electrolyte layers 13, 19. can.

Further, as shown in FIGS. 4 to 6, the first electrode layer 1
8 in a lattice shape and increasing the bonding area between the solid electrolyte layers 13 and 19 through the through holes 18a, the first
The occurrence of problems such as separation or peeling of the electrode layer 18 can be further prevented.

At this time, if the lower electrode layer 14 is also formed into a lattice shape, the adhesion of the lower electrode layer 14 can also be improved. Moreover, the first
If the electrode layers 12 and 18 are formed from conductive cermet layers containing the same components as either of the solid electrolyte layers 13 and 19, the bonding strength on each laminated surface can be further increased. This also applies when the second electrode layer 14 is formed from a conductive cermet layer. Furthermore, by laminating the five layers of the diaphragm layer 11, the solid electrolyte layer 19, the first electrode layer 12 (18), the solid electrolyte layer 13, and the second electrode layer 14 in an unfired state and then firing them simultaneously, Bonding strength can be further increased.

Further, when the protective layer 17 is coated, depending on the manufacturing process, it is also desirable to form a neck layer of six layers including the self-protective layer 17 in an unfired state and fire them simultaneously. Therefore, in each of the embodiments described above, alumina, mullite, spinel, forsterite, steatite, etc. can be used as the material for the diaphragm layer 11, or cermet, which is a mixture of ceramics and metal, can also be used. I can do it.

When the diaphragm layer 11 is used as a structural base, a green shift, press-molded body, or false-shape body made of a powdered viscous body of the above-mentioned material can be used. In addition, the material of the oxygen ion conductive solid electrolyte layers 13 and 19 is Ca
o, Y203, S, Mg0, m02, W03, Ta2
2 of Z stabilized with 05 etc. or Nb2Q, Sr
Bj stabilized with ○, W03, Ta2Q, Y203, etc.
203, and Y stabilized with Tho2, Ca○, etc.
203 etc. can be used.

At this time, in the present invention, not only the solid electrolyte layers 13 and 19 have the same components, but also the basic components (Zr02,
Bi203, etc.) and stabilizers (Ca○, Y203, etc.)
is the same but the ratio of the stabilizer is slightly different,
It also includes cases in which even if the basic components are the same but the stabilizers are different, there is not much difference in the coefficient of thermal expansion. When forming the solid electrolyte layers 13 and 19, a printing method using paste or a physical vapor deposition method such as sputtering can be employed. In this case, at least one of the diaphragm layer 11, the solid electrolyte layer 19, and the solid electrolyte layer 13 is formed to be gas permeable. The materials for the electrode layers 12, 14, and 18 include Au, Ag, and SIC, which do not have catalytic properties, and platinum group elements such as Ru, Pd, Rh, Melon, Lr, and Pt, which have catalytic properties, or their alloys, or platinum. An alloy of a group element and a base metal element can be used, and a cermet or the like can be used, which is a mixture of the metal or alloy and a ceramic, preferably a ceramic having the same components as the solid electrolyte layers 13 and 19.

When forming the electrode layers 12, 14, 18, physical vapor deposition methods such as sputtering and vacuum evaporation, electrochemical adhesion methods such as plating, or printing methods using paste may be employed. can. In addition, when providing the protective layer 17, its material may be alumina, mullite,
Spinel, calcium zirconate, etc. can be used, and coating methods such as immersion method, physical vapor deposition method such as sputtering, irradiation method using plasma, printing/coating method using paste, etc. are used. be able to.

Furthermore, when providing the heat-generating conductor layer 31, metal resistance materials such as Pt, W, and Mo can be used as the material, and printing methods using pastes containing these materials, embedding methods of pongee wire, etc. can be formed by
Manufacturing Example 1 Here, a stacked membrane oxygen sensor having a cross-sectional structure basically shown in FIG. 3 was manufactured.

Further, the manufacturing process is shown in FIG. Therefore, as shown in Fig. 7a, two platinum wires (0.2 x 7) are placed on the alumina green sheet (5 x 9 x 0.7 skin) 11a, and the lead wires 15a, 15b, and above it is shown Figure 7b.
Another alumina green sheet (5 x 9 x 0.7 ribs) 11b with two through holes 15c and 15d as shown in
The diaphragm layer 11 in an unfired state was formed by pressing and layering the diaphragm layer 11 horizontally.

Next, as shown in FIG. 7c, on the diaphragm layer 11 (on the alumina green sheet 11b), a solid electrolyte powder consisting of 5 mol% Y203 - 95 mol% Zr02 and lacquer were added in a weight ratio of 7:3. The solid electrolyte paste mixed and kneaded was printed, dried, and a solid electrolyte layer 19 in an unfired state was laminated.

At this time, the thickness of the solid electrolyte layer 19 after drying is 10 to 1
2 Adjusted to give Buddha skin. Next, as shown in FIG. 7d, a platinum paste made by mixing and kneading platinum powder and lacquer at a weight ratio of 7:3 is printed on the solid electrolyte layer 19, dried and unfired. The first electrode layer 12 in this state was layered horizontally. The thickness of the first electrode layer 12 after drying at this time was 6 to 7 mm. Next, as shown in Figure 7e,
On the first electrode layer 12, a solid electrolyte powder consisting of 5 mol% Y203-95 mol% Z2 and lacquer were mixed in a weight ratio of 7:
A solid electrolyte paste mixed and kneaded at a ratio of 3:3 was printed, dried, and a solid electrolyte layer 13 in an unfired state was laterally layered.

Note that during printing, the thickness of the solid electrolyte layer 13 after drying was set to 20 to 22 mm. Furthermore, Fig. 7 f
As shown in the figure, a platinum paste made by mixing and kneading platinum powder and lacquer at a weight ratio of 7:3 is printed on the solid electrolyte layer 13, and the second electrode layer 14 in an unfired state is laminated thereon. At the same time, the platinum burst is also dropped into the through holes 15c and 15d to form the lead portion 1 as shown in FIG. 7g.
5e and 15f were formed and then dried.

The thickness of the 0th electrode layer 14 after drying was 9 to 7 r.
The thus-prepared five-layer laminate in a fired state was simultaneously fired in the atmosphere at 1500 q×2 hours. Further, as shown in FIG. 7h, calcium zirconate (Ca0-Z2) powder was deposited on the entire surface as a protective layer 17 by plasma spraying.

The layer thickness at this time was 80 to 100 μm. The oxygen sensor 20A manufactured in this manner was mounted in a holder as shown in FIG. 8 and subjected to the following evaluation test. The oxygen sensor 20A mounted on the holder shown in FIG. 8 is protected by a stainless steel louver 21, and the gas to be measured flows in and out through a gas permeation hole 21a formed in the looper 21. This louver 21 is welded and fixed to a stainless steel casing 23 provided on the outer periphery of an alumina protection tube 22, and a platinum lead wire 1 is provided inside the alumina protection tube 22.
5a, 15b are provided with insertion holes 22a, and the platinum lead wires 15a, 15b passing through these are inserted into the rubber filler 24.
and penetrates inside the alumina powder insulator 25. This alumina powder insulator 25 is protected on the outside by a stainless steel tube 26, which is welded to the stainless steel casing 23 and has a fixing nut 27 on its outer periphery. The fixing nut 27 is used to fix the holder to, for example, an exhaust pipe. Manufacturing Example 2 Here, an oxygen sensor having the cross-sectional structure shown in FIG. 4 was manufactured.

Therefore, in the same manner as in Production Example 1, an unfired diaphragm layer 11 was formed by overlapping two alumina green sheets 11a and 11b, and then on the diaphragm layer 11, 5
Printed using a solid electrolyte paste made by mixing and kneading solid electrolyte powder consisting of 203-95 mol% Z with lacquer at a weight ratio of 7:3, and drying it to produce an unfired solid. An electrolyte layer 19 was laminated.

At this time, the thickness of the solid electrolyte layer 19 after drying is 10 to 1
I made it so that there are 2 mountains and rivers. Next, as shown in FIG. 9a, a platinum paste made by mixing and kneading platinum powder and lacquer at a weight ratio of 7:3 is printed in a grid pattern on the solid electrolyte layer 19, and dried. Then, a lattice-shaped first electrode layer 18 in an unfired state and having through holes 18a was formed as a neck layer.
At this time, the thickness of the first electrode layer 18 after drying was 6 to 7 mm. Subsequently, on the first electrode layer 18, a layer shown in FIG.
As shown in the figure, a solid electrolyte base made by mixing and kneading solid electrolyte powder consisting of 5 mol% Y203-95 mol% Zr02 and lacquer at a weight ratio of 7:3 is printed, dried and unfired. The solid electrolyte layer 13 in the state was competitively laminated. At this time, the thickness of the solid electrolyte layer was adjusted to be 20 to 22 mm thick. Next, as shown in Figure 9b,
A platinum paste prepared by mixing and kneading platinum powder and lacquer at a weight ratio of 7:3 was printed on the solid electrolyte layer 13, and dried to laminate the zeroth electrode layer 14 in an unfired state.

The thickness of the 0th electrode layer 14 after drying at this time was 6 to 7 inches thick. At the same time, platinum paste was also poured into the through holes 15c and 15d to form lead portions 15e and 15f as shown in FIG. 9b. Furthermore, as shown by diagonal lines in FIG. 9c, an alumina base is printed on the entire surface, which is made by mixing and kneading alumina powder and lacquer, which have the same components as those of the diaphragm layer 11, at a weight ratio of 7:3. A thin protective layer 17 was formed in an unfired state.

The unfired laminate consisting of the six layers stacked one after another in this manner was simultaneously fired in the atmosphere for 1500 pm x 2 hours.

The oxygen sensor 20B thus obtained was mounted in the holder shown in FIG. 8 and subjected to the next evaluation test. Comparative Example Here, in order to conduct an evaluation test of the product of the present invention, subordinate oxygen sensors having cross-sectional structures as shown in FIGS. 1 and 2 were manufactured.

The manufacturing steps at this time are shown in FIGS. 10 and 11, respectively. Therefore, the diaphragm layer 1 was created using two alumina green sheets similar to those shown in FIGS. 7a and 7b.

At this time, there is a 10th layer between the two alumina green sheets.
Two platinum lead wires 5 as shown in Figure a and Figure 11.
One end sides of a and 5b are buried. Next, as shown in FIG. 10a, a platinum paste made by mixing and kneading platinum powder and lacquer at a weight ratio of 7:3 is printed on the one diaphragm layer 1, dried and left untreated. The first electrode layer 2 in the fired state was heated.

Further, as shown in FIG. 11a, the platinum paste is printed in a lattice shape on the other corneal membrane layer 1, and dried to form a lattice-shaped first electrode layer in an unfired state and having through holes 8a. 8 were laminated. Subsequently, as shown in FIG. 10b and FIG. 11b, two solid electrolyte powders and lacquer with a weight ratio of 5 mol% Y203 to 95% mol% Z are placed on the first electrode layers 2 and 8. A solid electrolyte layer paste mixed and kneaded at a ratio of 7:3 was printed, dried, and a solid electrolyte layer 3 in an unfired state was laminated. Furthermore, as shown in FIGS. 10c and 11c, the same platinum paste as above was printed and dried,
A third electrode layer 4 in an unfired state was laminated. At the same time, lead parts 5c and 5d are formed to connect each electrode layer 2 and 4 to the platinum lead wire 5.
This enabled electrical continuity between the terminals a and 5b. In addition, the thickness of both polar layers 2 and 4 in the unfired state is 6 to 7 mm.
The thickness of the solid electrolyte layer 3 was 20 to 22 mm thick. Then, the laminate thus created was placed in the atmosphere for 150 minutes.
After simultaneous firing under the conditions of 0oo x 2 hours, Fig. 10 d
Then, as shown by diagonal lines in FIG. 11d, calcium zirconate powder was deposited on the entire surface by plasma spraying to cover the protective layer 7. Oxygen sensor 1 thus obtained
0A and 108 (first electrode layer 8 having a grid shape) were mounted in a holder shown in FIG. 8 and subjected to the following evaluation test. Test Example 1 A durability test was conducted using oxygen sensors 20A, 20B, 10A, and 10B in a car pen with the engine fully open.

At this time, the engine exhaust gas is in a rich atmosphere.

That is, the atmosphere is on the fuel-excess side where CO=5% and the air-fuel ratio is lower than the stoichiometric air-fuel ratio (approximately 14.7 in the case of gasoline combustion). Further, the exhaust gas temperature was 83,000. Therefore, five oxygen sensors 20A and 20B according to the present invention and five conventional oxygen sensors OA and 10B were tested to compare their durability in a rich atmosphere and at a constant exhaust gas temperature. As a result, with the conventional oxygen sensor OA, within 5 field hours of durability time, 5
In all cases, peeling occurred at the joint surface of the first electrode layer 2.

Further, in the conventional oxygen sensor 10B, all five of the sensors had peeled off at the mating surface of the first electrode layer 8 after being used for 20 tests. On the other hand, the oxygen sensor 20A of the present invention
Now, even after 200 hours of durability, and in the case of oxygen sensor 20B, even after 25 hours of durability, the first electrode layer 1
2 and 18 are in close contact with both solid electrolyte layers 13 and 19,
No separation or peeling was observed on the bonded surfaces, and it was confirmed that the durability was significantly improved. As detailed above, according to the present invention, a solid electrolyte layer having basically the same composition as the solid electrolyte layer acting as an oxygen concentration battery is provided between the diaphragm layer and the first electrode layer. , it is possible to create a laminated membrane slow-forming oxygen sensor in which the adhesive strength at the bonding surface of the first electrode layer is significantly increased, especially in cases where low and high temperature conditions are repeated, such as automobile engine exhaust gas, and high temperature and high speed flow. This has a very beneficial effect in that the first electrode layer does not separate or peel even under certain usage environments and has excellent durability.

[Brief explanation of the drawing]

1 and 2 are both schematic sectional views of a conventional stacked membrane structure oxygen sensor, and FIGS. 3 to 6 are schematic sectional views of a stacked membrane structure oxygen sensor in each embodiment of the present invention. 7a to 7h are explanatory diagrams showing the manufacturing process of an oxygen sensor in Manufacturing Example 1 of the present invention, FIG. 8 is a longitudinal cross-sectional view of a holder to which an oxygen sensor is attached, and FIGS. 9a to 9c are manufacturing steps of the present invention. Example 2
FIGS. 10 a to d and 11 a to d are explanatory diagrams showing the manufacturing process of a conventional oxygen sensor in a comparative example of the present invention, and FIG. 13 is an explanatory diagram showing the output characteristics of the oxygen sensor shown in FIG. 5. FIG. 13 is an explanatory diagram showing the output characteristics of the oxygen sensor shown in FIG. 11... diaphragm layer, 12, 18... first electrode layer, 13... oxygen ion conductive solid electrolyte layer,
14... nth electrode layer, 19... oxygen ion conductive solid electrolyte layer. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 8 Figure 9 Figure 7 Figure 10 Figure 11 Figure 12 Figure 13

Claims (1)

[Scope of Claims] 1. A diaphragm layer, a first electrode layer, an oxygen ion conductive solid electrolyte layer, and a second electrode layer are sequentially laminated, and at least one of the diaphragm layer and the oxygen ion conductive solid electrolyte layer is In the laminated membrane oxygen sensor, the second electrode layer is made gas permeable so that the second electrode layer can come into contact with the gas to be measured, and the potential difference generated between the two electrode layers is measured. and an oxygen ion conductive solid electrolyte layer having basically the same composition as the solid electrolyte layer. 2. The solid electrolyte layer provided between the diaphragm layer and the I-th electrode layer and the solid electrolyte layer provided between the I-th electrode layer and the II-th electrode layer are of the same composition including the stabilizer. A laminated film oxygen sensor according to claim 1. 3 Claims 1 or 2 formed by co-firing the diaphragm layer, the oxygen ion conductive solid electrolyte layer, the first electrode layer, the oxygen ion conductive solid electrolyte layer, and the second electrode layer.
The laminated membrane oxygen sensor described in . 4. The laminated membrane oxygen sensor according to any one of claims 1 to 3, wherein at least one of the I-th electrode layer and the II-th electrode layer is formed of a grid-like electrode layer. 5. Any one of claims 1 to 4, wherein at least one of the first electrode layer and the second electrode layer is formed from a conductive cermet layer containing the same component as either of the solid electrolyte layers. A laminated membrane oxygen sensor described in Crab. 6. The laminated type according to any one of claims 1 to 5, wherein a DC power source is connected between the I-th electrode layer and the II-th electrode layer to cause movement of oxygen ions through the solid electrolyte layer. Membrane oxygen sensor.