JP2001343354A - Gas sensor element and gas sensor equipped with it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas sensor element which enables to prevent a solid electrolyte from generating a crack starting from the peripheral line of an electrode part, and a gas sensor equipped with the gas sensor element. SOLUTION: In this gas sensor element provided with a solid electrolyte, a reference electrode 14a placed on one surface of the solid electrolyte, and a detecting electrode 14b placed on the other surface and coming into contact with a gas to be detected, and the length of the continuous part, where the shortest distance between the peripheral line 1411a of the reference electrode 141a and the peripheral line 1411b of the detecting electrode 141b is 3 times or less the thickness of the solid electrolyte, is set tenth or less of the peripheral line of the shorter electrode, especially twelfth or less. A crack easily to occur when the thickness of the reference electrode and the detecting electrode are relatively large, but its occurrence can be controlled in the above constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to oxygen gas and NO contained in exhaust gas discharged from an internal combustion engine of an automobile or the like.
The present invention relates to a gas sensor element capable of detecting x-gas or the like and not generating cracks in the solid electrolyte body starting from the outer peripheral lines of the reference electrode and the detection electrode, and a gas sensor including the same.

[0002]

2. Description of the Related Art Conventionally, a gas sensor element (hereinafter, may be simply referred to as an "element") using a cylindrical solid electrolyte or a plate-shaped solid electrolyte has been known. Among them, Japanese Patent Application Laid-Open No. 7-55758 discloses an element having a plate-shaped solid electrolyte body laminated in contact with an alumina substrate. In such a gas sensor element, a reference electrode that does not directly contact the gas to be detected and a detection electrode that contacts the gas to be detected are formed on the front and back surfaces of the solid electrolyte body, respectively, and a voltage generated between these electrodes is detected. And detecting the current flowing between these electrodes,
Thus, the concentration of oxygen gas and the like contained in the gas to be detected can be detected.

[0003]

However, in such a gas sensor element, the positions of the outer peripheral lines of the respective electrode portions of the reference electrode and the detection electrode formed on the front and back surfaces of the solid electrolyte body are set to a certain length. It has been found by the inventors of the present invention that cracks occur in the solid electrolyte body starting from these outer lines if they match. The cause of such cracks is due to the difference in thermal contraction during firing between the electrode made of Pt or the like and the solid electrolyte made of ceramics such as zirconia or alumina, etc. It is presumed that this is because a stress in the plane direction is applied to the substrate. Thus, cracks are more likely to occur when the solid electrolyte body is thin and when the electrodes are relatively thick.

In particular, when the solid electrolyte is formed by printing, the thickness of the solid electrolyte is 30 to 60 μm.
m is generally used, and there is a problem in terms of cost such that three or more printing steps are required to make the thickness 90 μm or more. Furthermore, if the solid electrolyte body is too thick,
There is also a problem that cracks are easily caused by a difference in thermal expansion between the solid electrolyte body and the substrate by itself. Therefore, especially when the solid electrolyte body is formed by printing, the thickness is 90 μm.
It was desirable to make it thinner than m. However, for the above-described reason, when such a thin solid electrolyte body is used, there is a problem that a crack is generated by stress from the electrode.

The present invention has been made to solve the above-mentioned conventional problems, and it is possible to suppress the occurrence of cracks in the solid electrolyte body in the vicinity of the outer peripheral line of the electrode portion during manufacturing. An object of the present invention is to provide a gas sensor element having excellent durability, for example, capable of suppressing generation of cracks in an electrolyte body, and a gas sensor including the element. In particular, it is an object of the present invention to provide a gas sensor element in which a solid electrolyte body is prevented from cracking when the solid electrolyte body is formed thinner than 90 μm on an insulating substrate.

[0006]

According to a first aspect of the present invention, there is provided a gas sensor element comprising: a solid electrolyte; and a reference electrode disposed in contact with one surface of the solid electrolyte and having a reference electrode and a reference electrode lead. A gas sensor element provided in contact with the other surface of the solid electrolyte body and having a detection electrode portion and a detection electrode lead portion, wherein a part of an outer peripheral line of the reference electrode portion and the detection portion facing the detection electrode portion; Part of the outer circumference of the electrode part,
No crack is generated in the solid electrolyte body from the starting point.

A gas sensor element according to a second aspect of the present invention is provided with a solid electrolyte member and one surface of the solid electrolyte member.
A reference electrode having a reference electrode portion and a reference electrode lead portion,
A gas sensor element comprising a detection electrode disposed in contact with the other surface of the solid electrolyte body and having a detection electrode portion and a detection electrode lead portion, wherein the outer periphery of the reference electrode portion and the outer periphery of the detection electrode portion The length of the continuous portion whose shortest distance to the line is 3.0 times or less the thickness of the solid electrolyte body is the shorter of the outer peripheral line of the reference electrode portion and the outer peripheral line of the detection electrode portion. Is not more than 1/10 of the outer peripheral line.

The above-mentioned "reference electrode portion" and the above-mentioned "detection electrode portion"
Is formed at opposite positions on the front and back surfaces of the solid electrolyte body, a voltage associated with the movement of oxygen ions generated between these electrodes, or a current flowing between these electrodes is detected and taken out as a signal. It is. The shape, area, thickness, and the like of the reference electrode portion and the detection electrode portion are not particularly limited, but the position of the “outer line” of each electrode portion is a considerable length opposed to the front and back surfaces of the solid electrolyte body. When the reference electrode portion and the detection electrode portion are formed so as to coincide with each other (hereinafter, such a state may be expressed as overlapping of the outer peripheral lines), these electrode portions Due to the difference in thermal expansion between the solid electrolyte body and the solid electrolyte body, a stress in a planar direction is applied to the solid electrolyte body, and cracks are generated in the solid electrolyte body starting from the outer peripheral lines of the respective electrode portions.

The occurrence of the crack will be described in detail with reference to FIGS. FIG. 1 shows a plan shape of a reference electrode and a detection electrode in a gas sensor element in which a crack does not occur in a solid electrolyte body as in the first invention. On the other hand, FIG. 2 shows a planar shape of a reference electrode and a detection electrode in a conventional gas sensor element in which a crack may occur in the solid electrolyte body. 1 and 2, the reference electrode 14a is a reference electrode portion 141a.
And a reference electrode lead portion 142a extending therefrom for transmitting a signal from the electrode portion to a signal extraction terminal. Further, the detection electrode 14b is
And a detection electrode lead portion 142b extending therefrom for transmitting a signal from the electrode portion to a signal extraction terminal. Each edge of the reference electrode lead portion and the detection electrode lead portion may be a signal extraction terminal as it is,
It may be connected to a signal extraction terminal formed on the element surface by a through hole or the like.

According to FIG. 1, an outer peripheral line 1411a of the reference electrode portion 141a and an outer peripheral line 1411a of the detection electrode portion 141b are provided.
b overlaps the four points A, B, C and D,
The lines do not overlap at all. This means that in the second invention, there is no continuous portion where the shortest distance between the outer peripheral line of the reference electrode portion and the outer peripheral line of the detection electrode portion is 3.0 times or less the thickness of the solid electrolyte body. Means
If the element is provided with the reference electrode and the detection electrode having such a shape, no crack is generated in the solid electrolyte body starting from the outer peripheral line of the electrode portion.

On the other hand, according to FIG. 2, the reference electrode portion 141a
Outer line 1411a and outer line 1 of sensing electrode portion 141b
411b overlaps over a considerable length like the outer peripheral line L. This is because, in the second invention, the shortest distance between the outer peripheral line of the reference electrode portion and the outer peripheral line of the detection electrode portion is 3.0 times or less the thickness of the solid electrolyte body (in the outer peripheral line L in FIG. The shortest distance between the respective outer peripheral lines is the thickness of the solid electrolyte body itself, that is, one time the thickness of the solid electrolyte body. It means that it is more than 1/10 of the shorter outer peripheral line of the outer peripheral line of the portion (the outer peripheral line of the reference electrode portion is shorter in FIG. 2). In the element including the detection electrode, cracks occur in the solid electrolyte body starting from the outer peripheral line L.

Further, even if there are portions where the outer peripheral line of the reference electrode and the outer peripheral line of the detection electrode are parallel over a length exceeding 1/10 of the shorter one of them, Are separated, that is, when the shortest distance between the respective outer lines is 2.0 times or more of the thickness of the solid electrolyte body, particularly 3.0 times or more, the cracks in the solid electrolyte body Occurrence can be suppressed. Further, the shortest distance between each of the outer peripheral lines over a considerable length is equal to the thickness of the solid electrolyte body.
Even if it is 0 times or less, if its length is 1/10 or less, especially 1/12 or less of the shorter one of the outer circumference of the reference electrode section and the outer circumference of the detection electrode section, There is no crack in the solid electrolyte body.

Further, the crack is more likely to occur when the portion where the outer peripheral line overlaps is linear, and the crack is more likely to propagate than when it is curved. For this reason, it is particularly preferable that there is no portion where the outer peripheral line linearly overlaps. Therefore, it is preferable that each electrode portion has a shape in which the outer peripheral line is formed by a curve, such as an ellipse rather than a rectangle. By doing so, it is possible to obtain an element that is less likely to generate a crack and that is less likely to propagate even if a crack is generated.

Further, as the reference electrode portion and the detection electrode portion are relatively thicker than the solid electrolyte body, cracks are more likely to occur. Particularly, when the solid electrolyte body is relatively thin, the thickness of each electrode portion is increased. Effect is greater. Therefore, the thickness of each electrode part is preferably ／ or less, particularly １ ／ or less, more preferably １ ／ or less of the thickness of the solid electrolyte body as in the third invention. As described above, by reducing the relative thickness of each electrode portion, cracks in the solid electrolyte body can be more reliably prevented.

The reference electrode and the detection electrode can be formed of a noble metal element having a catalytic action, such as platinum, ruthenium, osmium, iridium, rhodium, palladium, or a conductive material mainly containing these noble metal elements. . These electrodes are formed as thin films on the front and back surfaces of the solid electrolyte body by a normal method such as a printing method, a plating method, and a sputtering method.

The "solid electrolyte body" may have oxygen ion conductivity, and for example, a zirconia-based sintered body, LaGaO ₃ -based sintered body or the like having oxygen ion conductivity can be used.

It is preferable to provide a protective layer on the solid electrolyte body. The protective layer covers a part of the solid electrolyte body to prevent the occurrence of cracks and the like, and at the same time, covers the detection electrode to protect it from the environment such as outside air. This protective layer,
At a temperature of 900 ° C., it is preferable to have an insulation property 100 times or more as compared with the solid electrolyte body. Further, it is preferable to have airtightness of a degree having a relative density of 94% or more. The method for producing this protective layer is not particularly limited.
After printing and drying an insulating paste, it can be manufactured by firing integrally with other members. However, it is necessary that the solid electrolyte body be strong enough to suppress the force of peeling from the substrate, and it is preferable that the unfired ceramic sheet is laminated on another member and then fired integrally.

It is preferable that the substrate usually provided in this element is in the form of a plate, and the solid electrolyte body is formed in a layer in contact with at least a part of one surface of the substrate. The device of the present invention can be manufactured by using, for example, a technique for forming a laminate disclosed in Japanese Patent Application Laid-Open No. 7-55758. In the formation of the solid electrolyte body, a stack of unsintered sheets may be used, but it is preferable to form the solid electrolyte body by printing a paste. In this case, the substrate on which these are laminated is preferably in the form of an integral plate. This makes handling during manufacture particularly easy.

The solid electrolyte body contains 10 to 80% by mass, particularly 40 to 60% by mass of the constituent components of the substrate as in the fourth invention.
It is preferred to contain. Thereby, the thermal shock resistance of the solid electrolyte body can be improved, and the occurrence of cracks and the like can be further improved. The content of the components constituting the base is 80% by mass.
If it exceeds, it is difficult to obtain sufficient characteristics as a solid electrolyte body, which is not preferable. On the other hand, if it is less than 10% by mass, the thermal shock resistance is not sufficiently improved. Also, as in the fifth invention,
The solid electrolyte body is mainly composed of zirconia and alumina,
The substrate preferably contains alumina as a main component. Such a gas sensor element including a solid electrolyte body containing a large amount of alumina is preferable because it is inexpensive and has high durability.

A gas sensor according to a sixth aspect is provided with the gas sensor element according to the first to sixth aspects. This gas sensor is inexpensive and has high durability. Although the form of the gas sensor 2 is not particularly limited, for example,
The element 1 is disposed in the metal shell 21, and the metal shell 2 is arranged so that the detection unit disposed on the front side protrudes into the exhaust pipe or the like.
1 with a mounting screw portion 42 formed on the outer surface,
It can be used after being exposed to the gas to be measured (exhaust gas). According to this gas sensor, the gas to be detected can be detected stably for a long period of time.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail by way of examples. [1] Method of Manufacturing Element Having Peripheral Parts and Having Upper Insulating Layer on Peripheral Parts A method of manufacturing an element will be described with reference to FIGS. 3, 6, and 7. FIG. In the following manufacturing method, for ease of understanding, each pattern is printed on a sheet of one element size and laminated as shown in FIG. 3, but in an actual process, After printing the required number of green sheets of a size that can manufacture a plurality of elements and laminating,
An unfired laminate in the form of an element was cut out.

More specifically, a circular through hole 31 for positioning is formed near the short side of each green sheet 3 produced in the following (1) as shown in FIG. Occasionally, pins fixed to a printing machine or a laminating machine were inserted through these through holes to perform positioning. The size of the element was 42.85 mm in length and 3 in width when printing.
Each of the first to fourth green sheets was printed in parallel at the central portion of each of the first to fourth green sheets, and the printed patterns for ten elements were sequentially stacked as shown in FIG. Next, the integrally laminated body was cut along the broken line in FIG. 6 or 7 to obtain ten unfired laminated bodies having an element shape, and these were degreased and fired to produce an element.

The openings (square holes 32) are formed in the first to third green sheets from the top in FIG. 5 because each green sheet is laminated and then cut into elements. This is because each element is formed into a shape in which sheets of different lengths are aligned and stacked as shown in FIG. Explaining in correspondence with FIG. 1, the first green sheet from the top in FIG. 5 is 18b in FIG. 1, the second green sheet from the top is 18a, the third green sheet from the top is 11b, and the bottom green sheet in FIG. The sheets respectively correspond to 11a. 11
The reason why a square hole is formed in the third green sheet from the top in FIG. 5 even though the lengths of b and 11a are the same is that this square hole is for alignment of lamination. The end face of this square hole does not coincide with the end face on the tip side of 11b.

(1) Preparation of unsintered alumina sheet Alumina powder (purity 99.99% or more, average particle size 0.3
μm) 100 parts by mass (hereinafter abbreviated as “parts”), 14 parts of butyral resin, and 7 parts of dibutyl phthalate were blended and mixed using a mixed solvent consisting of toluene and methyl ethyl ketone to form a slurry. Four printing green sheets having a length of 90 mm and a width of 60 mm were produced by a doctor blade method. The first and fourth green sheets had a thickness of 0.4 mm, and the second and third green sheets had a thickness of 0.25 mm.

(2) Formation of heater pattern Alumina powder (purity 99.99% or more, average particle size 0.3
μm) A conductive layer paste containing 4 parts of platinum powder and 100 parts of platinum powder is printed on one surface of a first green sheet to be a lower half (11a; first substrate) of the base after firing and dried. After that, a heating portion pattern and a heater lead pattern were formed, and after firing, a heater pattern to be the heating resistor 12 (configured by the heating portion 121 and the heater lead portion 122) was formed. Next, a through hole 11 is provided near the base end of the first green sheet to establish conduction of the heating resistor.
1a is formed, and after baking, electrode pads 19 for connecting terminals are formed at positions corresponding to the through holes 111a on the back surface.
After the heater pad pattern a was formed, a second green sheet serving as the upper half (11b; second substrate) of the base was laminated on the heater pattern and fired, and then bonded by pressing.

(3) Formation of Buffer Layer Pattern A buffer layer paste containing 80 parts of alumina and 20 parts of zirconia is printed on the second green sheet of the ceramic laminate prepared in (2) and dried. After baking, a buffer layer pattern having a thickness of 30 ± 10 μ serving as the buffer layer 13 was formed.

(4) Formation of Reference Electrode Pattern On the buffer layer pattern formed in (3), the conductive layer paste used in (2) is printed, dried and fired. A reference electrode pattern having a thickness of 20 μm ± 10, which is constituted by a portion 141a and a reference electrode lead portion 142a. The planar shape of the reference electrode pattern was such that the reference electrode 14a of FIG. 1 was formed.

(5) Formation of First Solid Electrolyte Body Pattern Zirconia powder (purity 99.9% or more, average particle diameter 0.3
μm) 50 parts, alumina powder (purity 99.99% or more,
50 parts, average particle size 0.3 mm), butyl carbitol 3
3.3 parts, dibutyl phthalate 0.8 part, dispersant 0.5
Parts and 15 parts of binder, add the required amount of acetone,
After mixing for 4 hours, the acetone was evaporated to prepare a solid electrolyte paste. This solid electrolyte paste is
To cover the electrode part pattern part of the reference electrode pattern,
The first green sheet (and the second green sheet) is printed in a length direction of 13 mm in a length direction of 25 ± 10 μm, dried, fired, and partially and in the vicinity of the main body of the solid electrolyte body. A first solid electrolyte pattern to be the first solid electrolyte body 15a constituting the portion was formed.

(6) Formation of First Insulating Layer Pattern In the slurry prepared in (1), butyl carbitol 21 was added.
After adding 4 parts and the required amount of acetone and mixing for 4 hours,
The acetone was evaporated to prepare an insulating layer paste.
This insulating layer paste is printed on a portion of the buffer layer pattern where the first solid electrolyte layer pattern is not printed, dried and fired, and then the first insulating layer 16a which is a part of the insulating layer is formed. Thus, a first insulating layer pattern having a thickness of 25 ± 10 μm was formed.

(7) Formation of Second Solid Electrolyte Pattern The same solid electrolyte paste as in (5) was applied to the first solid electrolyte pattern at the same tip position for a length of 8 mm.
After printing to a thickness of 5 ± 10 μm, drying, and firing, a second solid electrolyte pattern to be the second solid electrolyte body 15b constituting a part of the solid electrolyte body was formed. in this way,
The solid electrolyte pattern has a thickness of 50
μm and a 25 μm-thick portion that becomes a peripheral portion after firing.

(8) Formation of Second Insulating Layer Pattern The same insulating layer paste as in (6) is printed and dried on the first insulating layer pattern on which the second solid electrolyte layer pattern is not formed. After the firing, the second insulating layer 16b constituting a part of the insulating layer, particularly, the portion on the first solid electrolyte pattern becomes the upper insulating layer 162 (a part of the second insulating layer 16b) after firing. A second insulating layer pattern having a thickness of 25 ± 10 μm was formed. In addition, through holes 161a and 161b for establishing conduction with the respective electrodes were formed near the base ends of the first and second insulating layer patterns.

(9) Formation of the sensing electrode pattern The conductive layer paste adjusted in (2) is printed on the second solid electrolyte pattern and the second insulating layer pattern formed in (7) and (8). , Dried and fired, the detection electrode 14
b (detection electrode portion 141b and detection electrode lead portion 142b
It consists of. ) To form a detection electrode pattern having a thickness of 20 μm ± 10. The plane shape of the detection electrode pattern was such that the detection electrode 14b of FIG. 1 was formed.

(10) Formation of porous layer pattern Carbon powder having an average particle size of 5 μm was mixed with the same paste for the insulating layer as in (6) at a volume ratio of 45% by volume with alumina,
A paste for a porous layer is prepared, printed on the second solid electrolyte pattern, dried, and fired to form a porous layer pattern having a length of 10 mm and a thickness of 50 μm or more that becomes the porous layer 17. did.

(11) Lamination of Third and Fourth Green Sheets After firing, the third green sheet to be the first protective layer 18a is formed so as to cover the portion excluding the porous layer pattern formed in (10). Then, a fourth green sheet to be the second protective layer 18b was laminated. In addition, through holes 181a and 181b for establishing continuity with each electrode are formed near the base ends of the third and fourth green sheets, and at positions corresponding to the through holes on the back surface of the fourth green sheet. After firing, a heater pad pattern to be an electrode pad 19b for connecting terminals was formed.

(12) Degreasing and firing The laminate obtained in (1) to (11) is heated from room temperature to 420 ° C. at a rate of 10 ° C./hour in an air atmosphere, and is held for 2 hours. The organic binder was degreased. Thereafter, in the air atmosphere, the temperature is raised to 1100 ° C. at a rate of 100 ° C./hour, further raised to 1520 ° C. at a rate of 60 ° C./hour, and held at this temperature for 1 hour for firing. As shown in FIG. 4, 300 gas sensor elements were obtained in which the solid electrolyte body was provided with a main body and a peripheral part, and the solid electrolyte body and the sensing electrode lead were separated by the upper insulating layer.

[2] An element in which the shape of the sensing electrode is changed In the same process as in [1], the shape of the reference electrode is fixed, and the shape of the sensing electrode, the positional relationship with the reference electrode, and the thickness of the solid electrolyte body are adjusted. Various elements were prepared by changing the mutual distance and the degree of overlap between the outer peripheral line of the reference electrode and the outer peripheral line of the detection electrode as shown in Table 1.

[0037]

[Table 1]

In Table 1, "the degree of overlap of the outer peripheral lines" means "(shortest distance between both electrode parts / thickness of solid electrolyte body)".
Is less than or equal to a predetermined value / the shorter outer circumference of the outer circumferences of the two electrode portions, and the degree of overlap between the outer circumference of the reference electrode portion and the outer circumference of the detection electrode portion defined in the second invention. Is represented. More specifically, 1 on the outer peripheral line of the reference electrode portion
Points such that a value obtained by dividing the shortest distance between the two electrode parts, which is expressed as the shortest distance between the point and the outer peripheral line of the sensing electrode part, by the thickness of the solid electrolyte body is equal to or less than a predetermined value are continuously formed. The ratio of the length on the outer peripheral line of the reference electrode portion to the shorter length of the outer peripheral lines of both electrode portions is used as a parameter representing the degree of overlap of the outer peripheral lines. Note that the predetermined value can be set as appropriate, but considering that if the predetermined value is large, cracks are originally unlikely to occur irrespective of the degree of overlap, the predetermined value exceeds 3 when evaluating the presence or absence of cracks. It is not preferable to set a large value.

The device prepared in [2] is immersed in water so that at least the solid electrolyte portion is completely immersed,
The resistance between the reference electrode and water was measured to evaluate the presence or absence of cracks. As a result, the device of the second invention (Experimental Examples 11 and 1)
In 5), no crack was generated, while in elements not included in the second invention (for example, Experimental Examples 3 and 7), cracks were generated. In addition, the thickness of the solid electrolyte body is 120 μm.
In the case described above (for example, Experimental Examples 25 and 28), generation of cracks can be sufficiently suppressed. Furthermore, as in the third invention, if the thickness of both electrode portions is made relatively thin with respect to the solid electrolyte body (Experimental Examples 29 to 31 and Experimental Examples 32 to 34).
And the generation of cracks can be more effectively suppressed. In particular, when the solid electrolyte body contains 10 to 80% by mass of alumina as a component of the substrate as in the fourth invention, the degree of overlap of the outer peripheral lines is set as in the second invention. Thereby, generation of cracks can be more effectively suppressed.

[0040]

According to the first aspect of the present invention, it is possible to provide a gas sensor element in which a crack does not occur in the solid electrolyte body due to a difference in heat shrinkage from the electrode portion. Further, by adopting the electrode configuration as in the second invention, it is possible to provide a gas sensor element in which cracking of the solid electrolyte body is suppressed. Further, according to the sixth aspect, by providing such an element, a gas sensor having excellent durability can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view schematically showing a reference electrode and a detection electrode used in a gas sensor element of the present invention.

FIG. 2 is a plan view schematically showing a conventional reference electrode and a detection electrode used in a gas sensor element.

FIG. 3 is an explanatory view illustrating a manufacturing process of the gas sensor element of the present invention.

FIG. 4 is a cross-sectional view of an example of the gas sensor element of the present invention.

FIG. 5 is a cross-sectional view of the gas sensor of the present invention.

FIG. 6 is a plan view of a green sheet for cutting out ten green laminates having an element shape from the center.

FIG. 7 is a schematic view showing a state in which four green sheets shown in FIG. 6 are stacked.

[Explanation of symbols]

1; gas sensor element, 11a; first base, 11b; second
Substrate, 111a; Through hole, 12; Heating resistor, 1
21; heat generating portion; 122; heater lead portion; 13; buffer layer; 14a; reference electrode; 141a; reference electrode portion;
1a; reference electrode outer peripheral line, 14b; detection electrode, 141b;
Detection electrode portion, 1411b; detection electrode peripheral line, 15a; first solid electrolyte body, 15b; second solid electrolyte body, 151;
Body layer, 152; peripheral layer, 16a; first insulating layer, 16
b; second insulating layer, 162; upper insulating layer, 17; porous layer, 18a; first protective layer, 18b second protective layer, 2; gas sensor, 21: metallic shell, 211;
3; green sheet, 31; through hole, 32; square hole.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiro Noda 14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi Inside Japan Special Ceramics Co., Ltd. (72) Inventor Kunio Yanagi 14-18 Takatsuji-cho, Mizuho-ku, Nagoya City Inside (72) Inventor Yusaku Hatanaka 14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi Inside Japan Special Ceramics Co., Ltd. (72) Inventor Shinya Awano 14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi Japan Special Ceramics Co. Terms (reference) 2G004 BB04 BC02 BD04 BE04 BE12 BE13 BE15 BE16 BE22 BF08 BF19 BG05 BH09 BJ03

Claims (6)

[Claims] 1. A solid electrolyte body, a reference electrode provided in contact with one surface of the solid electrolyte body, having a reference electrode portion and a reference electrode lead portion, and a reference electrode provided in contact with the other surface of the solid electrolyte body. In a gas sensor element including a detection electrode having a detection electrode portion and a detection electrode lead portion, a part of an outer peripheral line of the reference electrode portion and a part of an outer peripheral line of the opposed detection electrode portion are defined as starting points. A gas sensor element wherein no crack is generated in the solid electrolyte body. 2. A solid electrolyte body, a reference electrode provided in contact with one surface of the solid electrolyte body and having a reference electrode portion and a reference electrode lead portion, and a reference electrode provided in contact with the other surface of the solid electrolyte body. In a gas sensor element including a detection electrode having a detection electrode portion and a detection electrode lead portion, an outer peripheral line of the reference electrode portion, and a shortest distance between the outer peripheral line of the detection electrode portion and the solid electrolyte body. The length of a continuous portion that is 3.0 times or less of the thickness is 1/10 or less of the shorter one of the outer circumference of the reference electrode portion and the outer circumference of the detection electrode portion. Characteristic gas sensor element. 3. The gas sensor element according to claim 1, wherein the thickness of the reference electrode portion and the thickness of the detection electrode portion are not more than 2/3 of the thickness of the solid electrolyte member. 4. The solid electrolyte body according to claim 1, wherein the solid electrolyte body is disposed on a surface of an insulating substrate, and the solid electrolyte body contains 10 to 80% by mass of a component of the substrate. The gas sensor element according to claim 1. 5. The gas sensor element according to claim 1, wherein the solid electrolyte body has zirconia and alumina as main components, and the base has alumina as a main component. 6. A gas sensor comprising the gas sensor element according to claim 1. Description: