JP2019020290A - Solid electrolyte sensor - Google Patents

Abstract

To provide a solid electrolyte sensor in which a mixture of gases in two spaces across a solid electrolyte sensor element is suppressed.SOLUTION: A solid electrolyte sensor 1 is constituted to comprise: a first sealing layer 31 of ceramics in which a bottomed cylindrical body is formed due to the fact that the internal space of a cylindrical holder 20 is closed by a solid electrolyte sensor element 10 via a sealing layer 30, the sealing layer 30 joining the holder and the sensor element together; a second sealing layer 32 of glass joining the holder and the sensor element together, as well as covering the first sealing layer in one of two spaces (internal space S1 and external space S2) divided by the bottomed cylindrical body; and a third sealing layer 33 of ceramics joining the holder and the sensor element together, as well as covering the second sealing layer on the side opposite the first sealing layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a solid electrolyte sensor that detects a gas concentration using a solid electrolyte as a sensor element.

  Various solid electrolyte sensors that detect gas concentrations such as hydrogen gas, oxygen gas, carbon dioxide gas, and water vapor using solid electrolytes (ion conductive ceramics) as sensor elements have been proposed. Is going. The solid electrolyte sensor uses the principle of a concentration cell in which a potential difference is caused by the difference in concentration of the same ions, and occurs when the concentration of the gas to be detected is different in the two spaces between which the solid electrolyte is sandwiched. Measure power. Of the two spaces, if the concentration of the detection target gas is known in the first space, the gas concentration in the second space can be known from the measured electromotive force and the temperature of the sensor element by the Nernst equation. it can. Alternatively, when the gas concentration is unknown by creating a calibration curve in advance by measuring the electromotive force by changing the gas concentration in the second space while keeping the gas concentration in the first space constant From the measured value of the electromotive force, the gas concentration in the second space can be known.

  Therefore, in the solid electrolyte sensor, two spaces need to be partitioned by the solid electrolyte. In a conventional solid electrolyte sensor, a sensor element is fixed to one end of a cylindrical support member (holder), and the whole of the holder and the sensor element is formed into a bottomed cylindrical shape, thereby dividing two spaces ( For example, see Patent Document 1).

  However, in addition to this, it is difficult to completely and hermetically seal the sensor element and the holder, and it is a fact that a very small gap tends to remain. If there is even a slight gap between the sensor element and the holder, the gas in the two spaces will mix and accurate measurement will not be possible. In particular, when the concentration difference between the detection target gases in the two spaces is large, the influence of the gas mixture on the detection result is large. Further, if the molecule size of the detection target gas is small, it easily passes even if the size of the void is extremely small, and the influence of the gas mixing on the detection result is large.

JP 2011-174832 A

  Therefore, in view of the above circumstances, an object of the present invention is to provide a solid electrolyte sensor in which mixing of gases in two spaces sandwiching a solid electrolyte sensor element is suppressed.

In order to solve the above problems, a solid electrolyte sensor according to the present invention is:
“The inner space of the cylindrical holder is closed by a solid electrolyte sensor element via a sealing layer, and a bottomed cylindrical body is formed.
The sealing layer is
A first sealing layer of ceramics joining the holder and the sensor element;
A second sealing layer made of glass that joins the holder and the sensor element and covers the first sealing layer on one side of two spaces defined by the bottomed cylindrical body When,
A ceramic third sealing layer that joins the holder and the sensor element and covers the second sealing layer on the side opposite to the first sealing layer. " It is.

  In this configuration, the bottomed cylindrical body is formed by the sensor element closing the internal space of the cylindrical holder through the sealing layer, and the two spaces are partitioned by the bottomed cylindrical body. Has been. The sealing layer is formed by laminating a first sealing layer, a second sealing layer, and a third sealing layer in this order. Both the first sealing layer and the third sealing layer are ceramic layers, and the second sealing layer sandwiched between them is a glass layer.

  The first sealing layer and the third sealing layer of ceramic are layers in which the sensor element is supported by the holder. Since the ceramics have pores, the sensor element can be fixed to the holder, but the gap between the sensor element and the holder cannot be completely sealed. On the other hand, in this structure, the 2nd sealing layer of glass exists between the 1st sealing layer of ceramics, and the 3rd sealing layer. Therefore, when the solid electrolyte sensor is used or manufactured, the ceramic pores are filled with the softened glass when heated to a temperature equal to or higher than the softening point of the glass. Further, even if a very small gap exists between the ceramic layer (first sealing layer or third sealing layer) and the surface of the sensor element, the softened glass adheres to the surface of the sensor element. Adheres to ceramics and fills the gap. At the same time, even if a very small gap exists between the ceramic layer and the surface of the holder, the softened glass adheres to the surface of the holder and also adheres to the ceramic to fill the gap. As a result, the internal space of the cylindrical holder is hermetically closed by the sensor element via the sealing layer, so that mixing of gas in the two spaces partitioned by the bottomed cylindrical body is effectively suppressed. Is done.

  Here, when the glass constituting the second sealing layer is excessively softened during the use or manufacture of the solid electrolyte sensor, it flows along the surface of the sensor element to cover the electrode, or it falls down and is lost. There is a risk of being broken. On the other hand, in this structure, the ceramic layer coat | covers the 2nd sealing layer of glass from both sides. Since the ceramic has high heat resistance and does not soften at a temperature at which the glass softens, even if the glass of the second sealing layer is excessively softened, the flow and dripping can be prevented by the ceramic layer.

  As described above, the solid electrolyte sensor of the present configuration has the “sealing” action for closing the inner space of the holder with the sensor element in the ceramic first sealing layer and the third sealing layer, and the holder. It also functions as “fixing” to support the sensor element, enhances the “sealing” action by “softening ease” of the glass of the second sealing layer, and softens the second sealing layer. It is a configuration that prevents the flow and sagging, which are disadvantages due to ease, with a ceramic layer. The sensor element can be fixed to the holder only by the first sealing layer, and the sensor element can be fixed to the holder only by the third sealing layer, but there are two ceramic layers. , “Fixing” action is strong. In addition, when the solid electrolyte sensor is used in a direction in which the stacking direction in the sealing layer is the direction of gravity, the action of preventing the flow and dripping of the glass is the first sealing layer and the third sealing layer, The lower layer is mainly exerted.

  In the present invention, since the requirement for ceramics is only higher heat resistance than glass, ceramics exemplified by alumina, mullite, zirconia, and cordierite can be used without any particular limitation. The kind of ceramics of the first sealing layer and the ceramics of the third sealing layer may be the same or different.

In addition to the above configuration, the solid electrolyte sensor according to the present invention includes:
“The lower limit of the operating temperature range is T ₁ ° C and the upper limit is T ₂ ° C.
The ceramics of the first sealing layer and the ceramics of the third sealing layer exhibit heat resistance at T ₂ ° C.
The glass of the second sealing layer may have a softening point lower than T ₁ ° C.

  This defines the configuration of the solid electrolyte sensor in relation to the operating temperature range. Ceramics, such as alumina, mullite, and cordierite, exhibit heat resistance at least at 1200 ° C. Moreover, the softening point of general glass is 400 to 850 degreeC. On the other hand, the solid electrolyte has a temperature range suitable for use as a sensor depending on its composition, but is generally 600 ° C to 1000 ° C. Therefore, the solid electrolyte sensor of this configuration can be used without any problem within the operating temperature range of a general solid electrolyte sensor. In particular, the conventional solid electrolyte sensor has an advantage that it can be used without problems even at high temperatures (900 ° C. to 1000 ° C.) where it is difficult to keep the two spaces airtight and accurate measurement is difficult.

Even if the pores of the ceramic, the slight gap between the surface of the holder and the ceramic layer, or the slight gap between the surface of the sensor element and the ceramic layer are filled with glass softened by heating, There is a risk that pores will open again or voids may occur as the temperature decreases. In contrast, in the present configuration, as the glass of the second sealing layer, the temperature T ₁ ° C. above the softening point which is the lower limit of the temperature range of the solid electrolyte sensor uses a low glass. Therefore, when the solid electrolyte sensor is to be prevented from mixing gas in the two spaces, the two spaces can be surely partitioned in an airtight manner.

  As described above, as an effect of the present invention, it is possible to provide a solid electrolyte sensor in which mixing of gas in two spaces sandwiching a solid electrolyte sensor element is suppressed.

(A) The end view which cut | disconnected the solid electrolyte sensor of 1st embodiment of this invention in the vertical direction in the center, (b) The end surface which cut | disconnected the solid electrolyte sensor of the modification of 1st embodiment in the center in the vertical direction FIG. It is a figure which shows the result of having measured the change of the electromotive force when using the solid electrolyte sensor of 1st embodiment, and changing the oxygen concentration of measurement gas with measurement temperature. It is the end elevation which cut the solid electrolyte sensor of a second embodiment of the present invention at the center in the lengthwise direction. (A) The end view which cut | disconnected the solid electrolyte sensor of the other modification of 1st embodiment in the center in the vertical direction, and (b) The solid electrolyte sensor of the modification of 2nd embodiment cut | disconnected in the center in the vertical direction. FIG. (A) The end view which cut | disconnected the solid electrolyte sensor of the further modification of 1st embodiment in the center in the vertical direction, and (b) The solid electrolyte sensor of the other modification of 2nd embodiment in the center in the vertical direction. FIG.

  Hereinafter, the solid electrolyte sensor 1 which is 1st embodiment of this invention is demonstrated using FIG. Here, the case where this invention is applied to the solid electrolyte sensor 1 which measures the gas concentration in a gaseous phase is illustrated.

  The solid electrolyte sensor 1 has a bottomed cylindrical body formed by closing the internal space of a cylindrical holder 20 with a solid electrolyte sensor element 10 through a sealing layer 30. Of the two spaces S1 and S2 partitioned by the cylindrical body, the inner electrode 41 is provided on the surface of the sensor element 10 in the inner space S1, and the inner electrode 41 is provided on the surface of the sensor element 10 in the outer space S2. And an outer electrode 42.

  The sealing layer 30 includes a first sealing layer 31, a second sealing layer 32, and a third sealing layer 33. The first sealing layer 31 is a ceramic layer that joins the holder 20 and the sensor element 10 together. The second sealing layer 32 is a glass layer, which joins the holder 20 and the sensor element 10 and covers the first sealing layer 31 on the external space S2 side. The third sealing layer 33 is a ceramic layer, which joins the holder 20 and the sensor element 10, and is opposite to the first sealing layer 31, that is, the second sealing layer 32 in the external space S2. Is covered.

  If it demonstrates in detail, the holder 20 will be cylindrical and is formed with ceramics, such as an alumina. The sensor element 10 has a bottomed cylindrical shape, and the cylindrical portion 10s has a cylindrical shape. The sensor element 10 is fixed to one end side of the holder 20 by the sealing layer 30 in a state where the opening is located inside the holder 20.

  In the sealing layer 30, the second sealing layer 32 is in contact with the holder 20 at the lower end portion of the holder 20 from the end surface to the inner peripheral surface and so as to contact the outer peripheral surface of the cylindrical portion 10 s of the sensor element 10. The sensor element 10 is joined. The third sealing layer 33 reaches the outer peripheral surface of the cylindrical portion 10 s of the sensor element 10 across the boundary 12 between the portion in contact with the second sealing layer 32 and the portion not in contact with the sensor element 10. At the same time, the outer surface of the second sealing layer 32 (external space) is reached so as to reach the outer peripheral surface of the holder 20 across the boundary 22 between the portion in contact with the second sealing layer 32 and the portion not in contact with the holder 20. The entire surface on the S2 side is covered from the outside.

  Furthermore, the first sealing layer 31 is annularly interposed between the outer peripheral surface of the cylindrical portion 10s of the sensor element 10 and the inner peripheral surface of the holder 20, and both surfaces are joined together. It is laminated on the second sealing layer 32. The second sealing layer 32 is in contact with the portion of the holder 20 that is in contact with the first sealing layer 31 from the boundary 11 between the portion that is in contact with the first sealing layer 31 and the portion that is not in contact with the sensor element 10. The first sealing layer 31 is entirely covered over the boundary 21 with the portion that is not.

  The solid electrolyte sensor 1 further includes a protective tube 50 that is cylindrical and has a larger diameter than the holder 20. The holder 20 is inserted into the protective tube 50, and is fixed to the inner peripheral surface of the protective tube 50 by a fixing material 51. It is fixed to. Further, a gas introduction pipe 60 for introducing the reference gas or the measurement gas is inserted into the inner space S1 of the bottomed cylindrical body inside the holder 20.

The upper limit value T ₂ ° C of the use temperature range of the solid electrolyte sensor 1 having the above configuration is set to a temperature at which the ceramics of the first sealing layer 31 and the ceramics of the third sealing layer 33 exhibit heat resistance. Here, the first sealing layer 31 and the third sealing layer 33 can be formed by heating and drying an inorganic adhesive containing ceramics and a binder. By using an inorganic adhesive, the adhesiveness between the holder 20 and the sensor element 10 can be improved, and the first sealing layer 31 and the third sealing layer 33 can be formed with high work efficiency.

  Here, examples of the binder contained in the inorganic adhesive include colloidal silica, alkali metal silicates, and metal phosphates such as aluminum, magnesium, calcium, and zinc. By heating and drying such an inorganic adhesive and curing it, a ceramic first sealing layer and a third sealing layer are formed, respectively.

  The inorganic adhesive can contain a curing agent in addition to the ceramic and the binder. The strength and water resistance of the first sealing layer and the third sealing layer can be increased by the curing agent. When an alkali metal silicate is used as the binder, an oxide or hydroxide such as magnesium, calcium, or zinc, or a borate such as calcium, barium, or magnesium can be used as the curing agent. When a metal phosphate is used as the binder, an oxide or hydroxide such as magnesium, calcium, zinc, or aluminum, or a silicate such as calcium or magnesium can be used as the curing agent. On the other hand, when colloidal silica is used as the binder, no curing agent is required because it is cured by its gelation.

Moreover, as a commercially available inorganic adhesive, the heat resistant inorganic adhesive Aron ceramic (trademark) by Toa Gosei Co., Ltd. can be used conveniently, for example. Since Aron ceramic D mainly composed of alumina, Aron ceramic C principally composed of silica, Aron ceramic E mainly composed of zirconia and silica exhibit heat resistance at 1100 ° C. to 1200 ° C., solid electrolyte sensors The upper limit value T ₂ ° C of the operating temperature range of can be at least 1100 ° C.

As the glass of the second sealing layer 32, the lower limit value T ₁ ° C. above the softening point of the set temperature range as the working temperature of the solid electrolyte sensor uses a low glass. Usually, the operating temperature of the solid electrolyte sensor is 600 ° C. or higher. Therefore, the glass shown in the following Table 1 can be used as the glass of the second sealing layer with respect to the lower limit T ₁ ° C that can be set.

  As described above, by using a glass having a softening point lower than the operating temperature of the solid electrolyte sensor 1 as the glass of the second sealing layer 32, the glass is softened when the solid electrolyte sensor 1 is used. Thereby, even if pores exist in adjacent ceramic layers (first sealing layer 31 and third sealing layer 33), the softened glass fills the pores. Further, between the first sealing layer 31 and the surface of the sensor element, between the first sealing layer 31 and the surface of the holder 20, between the third sealing layer 33 and the surface of the sensor element, a third seal. Even if there are slight gaps between the stop layer 33 and the surface of the holder 20, the softened glass fills the gaps at the operating temperature of the solid electrolyte sensor 1.

  Therefore, when the solid electrolyte sensor 1 is required to be hermetically partitioned between the internal space S1 and the external space S2, the internal space S1 and the external space S2 are reliably sealed by the sealing layer 30. Therefore, mixing of gas between the internal space S1 and the external space S2 can be effectively suppressed.

  The second sealing layer 32 is covered with a ceramic first sealing layer 31 on the inner space S1 side and with a ceramic third sealing layer 33 on the outer space S2 side. Since the ceramic does not soften at the operating temperature of the solid electrolyte sensor 1, even if the glass of the second sealing layer 32 is excessively softened, it flows along the surface of the sensor element 10 and covers the outer electrode 42. The situation of falling or dripping is prevented by the ceramic layer. Here, as shown in FIG. 1A, the first sealing layer 31 is located above the second sealing layer 32, and the third sealing layer 33 is below and outward from the second sealing layer 32. The third sealing layer 33 mainly prevents dripping of the glass. In the present embodiment, the ceramic third sealing layer 33 reaches the outer peripheral surface of the cylindrical portion 10 s of the sensor element 10 across the boundary 12 and reaches the outer peripheral surface of the holder 20 beyond the boundary 22. Since the boundaries 12 and 22 are sufficiently covered, the softened glass does not have a possibility of flowing so as to ooze through the boundaries 12 and 22.

  In addition, a fixed state in which the sensor element 10 is firmly supported by the holder 20 is maintained by the ceramic first sealing layer 31 and the third sealing layer 33 that are not softened at the use temperature of the solid electrolyte sensor 1. The sensor element 10 can be supported by the holder 20 only by the first sealing layer 31 or only by the third sealing layer 33. However, since there are two ceramic layers, the sensor element 10 can be held by the holder. The fixed state supported by 20 is strong.

  Actually, the solid electrolyte sensor 1 was used to introduce a reference gas into the internal space S1, while a measurement gas in which the concentration of the detection target gas in the external space S2 was changed was introduced to measure changes in electromotive force. The detection target gas was oxygen gas, and the measurement gas was switched to air (oxygen concentration of about 21%), oxygen 1% -nitrogen 99%, oxygen 0.1% -nitrogen 99.9%, and nitrogen 100%. The lower limit value of the measurement temperature range was 850 ° C., and the upper limit value was 1000 ° C. This measurement temperature range is a high temperature range as the use temperature of the solid electrolyte sensor. The measurement results are shown in FIG.

  As is apparent from FIG. 2, the electromotive force rapidly changed in response to the change in the oxygen concentration, and the electromotive force was kept constant while the oxygen concentration was constant. Therefore, there is no gas mixing between the internal space S1 and the external space S2, and the two spaces are airtightly partitioned by the sealing layer 30 including the first sealing layer 31 to the third sealing layer 33. It was confirmed that

  As a modification of the first embodiment, a solid electrolyte sensor 1b having the configuration shown in FIG. In the solid electrolyte sensor 1 b, the joint portion between the second sealing layer 32 and the holder 20 reaches not only the end surface and inner peripheral surface of the holder 20 but also the outer peripheral surface at the lower end portion of the holder 20. The second sealing layer 32 is so formed that the third sealing layer 33 reaches the outer peripheral surface of the holder 20 across the boundary 22 and reaches the outer peripheral surface of the cylindrical portion 10 s of the sensor element 10 across the boundary 12. The entire outer surface (surface on the outer space S2 side) is covered from the outside. Even in the solid electrolyte sensor 1b having such a configuration, the above-described effects are exhibited in the same manner as the solid electrolyte sensor 1.

  Next, the solid electrolyte sensor 2 of the second embodiment will be described with reference to FIG. The solid electrolyte sensor 2 is different from the solid electrolyte sensor 1 of the first embodiment and the solid electrolyte sensor 1b of the modification in the manner of joining the holder 20 and the sensor element 10 by the sealing layer 30.

  Specifically, the second sealing layer 32 is annularly interposed between the inner peripheral surface of the holder 20 and the outer peripheral surface of the cylindrical portion 10 s of the sensor element 10 to join both surfaces. Similarly, the first sealing layer 31 is annularly interposed between the inner peripheral surface of the holder 20 and the outer peripheral surface of the sensor element 10 to join both surfaces. The second sealing layer 32 is in contact with the portion of the holder 20 that is in contact with the first sealing layer 31 from the boundary 11 between the portion that is in contact with the first sealing layer 31 and the portion that is not in contact with the sensor element 10. The first sealing layer 31 is entirely covered over the boundary 21 with the portion that is not.

  Similarly, the third sealing layer 33 is annularly interposed between the inner peripheral surface of the holder 20 and the outer peripheral surface of the sensor element 10 to join both surfaces. The third sealing layer 33 is in contact with the portion in contact with the second sealing layer 32 in the holder 20 from the boundary 12 between the portion in contact with the second sealing layer 32 and the portion not in contact with the sensor element 10. The second sealing layer 32 is entirely covered over the boundary 22 with the unexposed portion. Such a solid electrolyte sensor 2 also exhibits the above-described effects as in the case of the solid electrolyte sensors 1 and 1b.

  The present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to the above-described embodiments, and various improvements can be made without departing from the scope of the present invention as described below. And design changes are possible.

  For example, in the solid electrolyte sensors 1, 1 b, and 2, the sensor element 10 is held in the holder 20 by the sealing layer 30 in a state where the opening of the bottomed cylindrical sensor element 10 is opened inside the holder 20. It was an example fixed to one end of the. Without being limited thereto, as illustrated in FIG. 4A, the sensor element 10 is attached to the holder 20 by the sealing layer 30 so that the opening of the bottomed cylindrical sensor element 10 is opened outside the holder 20. The solid electrolyte sensor 1c may be fixed. Even in such a configuration, a bottomed cylindrical body is formed by the holder 20, the sealing layer 30, and the sensor element 10, and the internal space S1 and the external space S2 are partitioned. FIG. 4A is an example in which the configuration of the sealing layer 30 is the same as that of the solid electrolyte sensor 1, but the configuration of the sealing layer 30 is the same as that of the solid electrolyte sensors 1b and 2 and each has a bottom. A solid electrolyte sensor having a configuration in which the opening of the cylindrical sensor element 10 is opened outside the holder 20 may be used.

  Further, the solid electrolyte sensors 1, 1 b, and 2 are examples in which the sensor element 10 closes the inner space of the holder 20 through the sealing layer 30 on one end side of the holder 20. The solid state in which the sensor element 10 is fixed to the holder 20 by the sealing layer 30 in a state where the entire sensor element 10 is accommodated in the inner space of the holder 20 as illustrated in FIG. It can be set as the electrolyte sensor 2b. Even in such a configuration, a bottomed cylindrical body is formed by the holder 20, the sealing layer 30, and the sensor element 10, and the internal space S1 and the external space S2 are partitioned. FIG. 4B is an example in which the configuration of the sealing layer 30 is the same as that of the solid electrolyte sensor 2, but the configuration of the sealing layer 30 is the same as that of the solid electrolyte sensors 1 and 1 b and the sensor element. The solid electrolyte sensor may be configured to be fixed to the holder 20 in a state where the entire 10 is contained in the internal space of the holder 20.

  Furthermore, the solid electrolyte sensors 1, 1b, and 2 described above are examples in which the sensor element 10 has a bottomed cylindrical shape. It is not limited to this, It can be set as a plate-shaped and columnar sensor element. Regardless of the shape of the sensor element, the sensor element closes one end of the holder through the sealing layer, or the sensor element closes the inner space through the sealing layer in the middle of the holder. A bottomed cylindrical body is formed by the holder, the sealing layer, and the sensor element, and the internal space and the external space are partitioned. As an example, FIG. 5A shows a solid electrolyte sensor 1d in which a cylindrical sensor element 10b closes one end of a holder 20 through a sealing layer 30. FIG. Further, FIG. 5B shows a solid electrolyte sensor 2 c in which the cylindrical sensor element 10 b closes the inner space of the holder 20 through the sealing layer 30 in the middle of the holder 20.

  In the case of the bottomed cylindrical sensor element 10, the inner electrode 41 and the outer electrode 42 are provided on both surfaces of the bottom, the thickness of the bottom is reduced, and the distance between the inner electrode 41 and the outer electrode 42 is suppressed to be small. The bottomed cylindrical tubular portion 10s can secure a wide area to be brought into contact with the sealing layer 30, so that the sealing by the sealing layer 30 is easy to ensure and the sealing is performed. There is an advantage that the operation of providing the layer 30 is easy. On the other hand, the cylindrical sensor element 10b can ensure a wide area to be brought into contact with the sealing layer 30 on the outer peripheral surface thereof. 10b is solid and has an advantage of high mechanical strength.

1, 1b, 1c, 1d Solid electrolyte sensor 2, 2b, 2c Solid electrolyte sensor 10, 10b Sensor element 20 Holder 30 Sealing layer 31 First sealing layer (sealing layer)
32 Second sealing layer (sealing layer)
33 Third sealing layer (sealing layer)
41 inner electrode 42 outer electrode S1 inner space S2 outer space

Claims (2)

A bottomed cylindrical body is formed by closing the internal space of the cylindrical holder with a solid electrolyte sensor element through a sealing layer,
The sealing layer is
A first sealing layer of ceramics joining the holder and the sensor element;
A second sealing layer made of glass that joins the holder and the sensor element and covers the first sealing layer on one side of two spaces defined by the bottomed cylindrical body When,
A ceramic third sealing layer that joins the holder and the sensor element and covers the second sealing layer on the side opposite to the first sealing layer; A solid electrolyte sensor. The operating temperature range is T ₁ ° C to T ₂ ° C,
The ceramics of the first sealing layer and the ceramics of the third sealing layer exhibit heat resistance at T ₂ ° C.
The solid electrolyte sensor according to claim 1, wherein the glass of the second sealing layer has a softening point lower than T ₁ ° C.

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