JP2005153449A - Joining method of ceramic molded items, and manufacturing method of gas sensor element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a jointing method of molded items each made of a different ceramic material capable of preventing generation of warp and the like in the case of sintering a laminate obtained by laminating the molded items each made of the different ceramic material into one body, and to provide a manufacturing method of a gas sensor element using the method. <P>SOLUTION: In the jointing method of the ceramic molded items of laminating the molded items each made of the different ceramic material and integrating the laminate by sintering, a difference ΔT of an initiation temperature of shrinkage between the molded items each made of the different ceramic material during sintering is not more than 70°C, and the difference ΔS of the shrinkage ratio between the molded item having a higher initiation temperature of shrinkage and the molded item having a lower initiation temperature of shrinkage is not more than 1.5% at a temperature at which the shrinkage ratio of the molded item having the lower initiation temperature of shrinkage is 2%. The gas sensor element is made using the jointing method. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for joining ceramic molded bodies and a method for producing a gas sensor element using this method, and more specifically, suitable for producing a plate-like oxygen sensor element used for detecting oxygen concentration in exhaust gas from automobiles. The present invention relates to a method for joining ceramic molded bodies and a method for producing a gas sensor element.

In recent years, environmental issues have been highlighted, and efforts are being made to put the global environment as a top priority in each industry. In particular, in the automobile industry, as represented by the exhaust gas regulations of California, the United States, reducing the amount of CO ₂ , CO, HC, NOx in exhaust gas year by year has become a trend in the world. . Among them, in order to further reduce the gas in the exhaust gas, it is important how to burn the fuel efficiently. For that purpose, the residual oxygen amount in the exhaust gas is instantaneously measured and the information is obtained. There is a growing demand for oxygen sensors that can provide fast feedback to the combustion system.

  Up to now, oxygen sensors have used a heat of exhaust gas to raise the temperature of a cylindrical sensor sealed at one end to develop a sensor function. However, until the sensor function appears, the exhaust gas is in a state of running down, and it has become impossible to meet the recent strict exhaust gas regulations. Therefore, an oxygen sensor that actively heats a cylindrical sensor with a heater has been developed. By using such an oxygen sensor, the sensor function can be expressed quickly, and information can be fed back more responsively.

  However, in the cylindrical sensor, the size is inevitably increased, and the distance between the heater and the sensor unit is increased, so that the speed of the sensor function is limited. Therefore, recently, a plate-like oxygen sensor element has been developed in which the sensor portion is made into a plate shape, and the temperature rise speed is increased by integrally forming the sensor portion and the heater so that the sensor function can be expressed more quickly. An oxygen sensor provided is being developed (for example, Patent Document 1).

The oxygen sensor element described in Patent Document 1 is obtained by laminating and solidifying a solid electrolyte layer constituting a sensor part, an insulating layer (insulating base part) in which a heater is incorporated, and the like. However, since the ceramic material composing the solid electrolyte layer and the ceramic material composing the insulating layer have different components, it is not easy to set conditions such as lamination adhesion conditions and degreasing firing conditions, and warping often occurs during firing. is there. As described above, when the laminated sintered body constituting the oxygen sensor element is warped, there is a problem that the manufacturing yield is lowered and the cost is increased.
JP-A-8-5603

  An object of the present invention is to provide a bonding method for dissimilar ceramic molded bodies capable of suppressing the occurrence of warping and the like when a laminated body obtained by stacking formed bodies made of different ceramic materials is integrated by firing, and this method It is providing the manufacturing method of the gas sensor element using this.

  As a result of diligent research to solve the above problems, the inventors of the present invention, when firing a laminate in which compacts made of different ceramic materials are fired, the behavior of the initial shrinkage during firing of these compacts, By adjusting the shrinkage start temperature of the molded body and the shrinkage ratio at the initial stage of shrinkage within a predetermined range, a new fact that warpage can be suppressed during firing was found, and the present invention was completed. .

That is, the method for joining ceramic molded bodies and the method for producing a gas sensor element of the present invention have the following configurations.
(1) A method of joining ceramic molded bodies in which molded bodies made of different ceramic materials are laminated, and the laminated bodies are fired and integrated, and starts shrinking when the molded bodies made of different ceramic materials are fired. At a temperature at which the temperature difference ΔT is within 70 ° C. and the shrinkage rate of the molded product with a low shrinkage start temperature is 2%, the shrinkage rate difference ΔS with the molded product with a high shrinkage start temperature is within 1.5%. A method for joining ceramic molded bodies.
(2) A method of joining ceramic molded bodies in which molded bodies made of different ceramic materials are laminated, and the laminated bodies are fired and integrated, and starts shrinking when the molded bodies made of different ceramic materials are fired. At a temperature at which the temperature difference ΔT is within 70 ° C. and the shrinkage rate of the molded product with a low shrinkage start temperature is 1.5%, the shrinkage rate difference ΔS with the molded product with a high shrinkage start temperature is within 1%. A method for joining ceramic molded bodies.
(3) The joining method according to (1) or (2), wherein one ceramic material is zirconia ceramics and the other ceramic material is alumina ceramics.
(4) Any one of (1) to (3), wherein one of the molded bodies made of different ceramic materials is a molded body for a solid electrolyte layer, and the other is a molded body for an insulating base portion. The manufacturing method of the gas sensor element using the joining method of description.

  According to the method for joining ceramic molded bodies described in (1) to (3) above, the shrinkage start temperature difference between one ceramic molded body and the other ceramic molded body and the shrinkage rate difference at the initial stage of shrinkage are within a predetermined range. By adjusting, it is possible to suppress a warp during firing and obtain a laminated sintered body having a small warp. Thereby, since the fall of a manufacturing yield can be suppressed, mass productivity can improve and cost reduction can be aimed at.

  According to the method for producing a gas sensor element according to (4), it is possible to provide a high-quality oxygen sensor element with small warpage by using the bonding method according to any one of (1) to (3). In addition, since a decrease in manufacturing yield can be suppressed, mass productivity can be improved and costs can be reduced.

  Hereinafter, a method for joining ceramic molded bodies according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of an oxygen sensor element manufactured by using the method for joining ceramic molded bodies according to this embodiment, and FIG. 2 explains the structure of the oxygen sensor element. FIG.

  As shown in FIGS. 1 and 2, the oxygen sensor element of the present embodiment includes an insulating substrate in which a sensor unit 11 having a function of detecting an oxygen concentration and a heater 21 for heating the sensor unit 11 are contained. Part 15 and a porous protective layer 16 formed to protect the detection electrode 13 from poisoning by exhaust gas, and these are integrated by firing.

  The sensor unit 11 includes a solid electrolyte layer 12 having oxygen ion conductivity, a detection electrode 13 provided on the upper surface of the solid electrolyte layer 12, and a reference electrode 14 provided on the lower surface of the solid electrolyte layer 12. ing. Lead portions 18 and 19 are connected to the detection electrode 13 and the reference electrode 14, respectively. An electrode pad 31 is connected to the end of the lead portion 18, and an electrode pad 32 is connected to the end of the lead portion 19. The electrode pad 32 is electrically connected to an electrode pad 33 provided on the upper surface of the solid electrolyte layer 12 through a through hole (not shown).

  The insulating base portion 15 is formed by integrating the laminated ceramic molded bodies 15a, 15b, 15c for the insulating base portion and the heater 21 embedded in the molded bodies 15b, 15c by firing. Further, the molded body 15a is punched into a U shape by a mold. Thus, the oxygen sensor element is formed with a cavity portion (atmospheric introduction hole) 17 whose one end is sealed.

  The heater 21 includes a heating element 22, a lead portion 23 connected to the heating element 22 for supplying a current to the heating element 22, and an electrode pad 34 connected to an end portion of the lead portion 23. These are embedded in the insulating base 15. The electrode pad 34 is electrically connected to an electrode pad 35 provided on the lower surface of the insulating base portion 15 through a through hole (not shown).

As the ceramic material for the solid electrolyte layer 12, a solid electrolyte such as a zirconia ceramic material or a titania ceramic material can be used. As this solid electrolyte, rare earth oxides such as Y ₂ O ₃ , Yb ₂ O ₃ , Sc ₂ O ₃ , Sm ₂ O ₃ , Nd ₂ O ₃ , and Dy ₂ O ₃ are used as stabilizers in terms of oxides. partially stabilized ZrO ₂ or stabilized ZrO ₂ containing 15 mol%, or the like may be used ZrO ₂ which was a solid solution of alkaline earth elements.

  The ceramic material for the insulating base portion 15 is not particularly limited as long as it is an insulating ceramic, and for example, an insulating ceramic material such as alumina or forsterite can be used. In particular, the ceramic material for the solid electrolyte layer 12 may be zirconia ceramics, and the ceramic material for the insulating substrate 15 may be alumina ceramics.

  A known conductive metal material can be used as the material of the heating element 22, the lead portions 18, 19, 23, the detection electrode 13, the reference electrode 14, and the electrode pads 31 to 35. Specifically, for example, platinum, tungsten, or an alloy of platinum and one kind selected from the group consisting of rhodium, palladium, lutetium, and gold can be used. In particular, platinum, tungsten, and the like are preferable as these materials because they can be fired simultaneously with the ceramic material of the solid electrolyte and the insulating base portion. In addition, in order to adjust the resistance value, thermal expansion coefficient, and the like of the heating element 22, a co-material made of an inorganic material may be mixed.

  In the oxygen sensor including the oxygen sensor element of the present embodiment, the reference atmosphere (oxygen) is introduced into the cavity 17 in a state where the heating element 22 is energized and the solid electrolyte layer 12 is heated to about 400 to 1000 ° C. The detection electrode 13 is disposed in a measurement atmosphere such as exhaust gas. As a measurement method, a concentration cell type in which an electromotive force generated between the detection electrode 13 and the reference electrode 14 is measured to measure the oxygen concentration in the exhaust gas may be used. A limiting current type for measuring the concentration may be used.

  In the present invention, when the oxygen sensor element as described above is manufactured, a molded body made of different ceramic materials, that is, a ceramic molded body for the solid electrolyte layer 12 and a ceramic molded body for the insulating base portion 15 are formed by these. The shrinkage start temperature difference ΔT between the compacts and the shrinkage ratio difference ΔS at the beginning of shrinkage are adjusted within the following predetermined range.

  FIG. 3 is a graph showing the relationship between the firing temperature and the shrinkage ratio of the ceramic molded body. The solid line represents the shrinkage behavior of the ceramic molded body with the lower shrinkage start temperature, and the broken line represents the shrinkage behavior of the ceramic molded body with the higher shrinkage start temperature. Here, the shrinkage start temperature refers to the temperature at which the ceramic molded body starts to shrink when the temperature is raised during firing. The shrinkage ratio is obtained by dividing the difference between the dimensions of the molded body before firing and the dimensions of the molded body at a certain temperature during firing by the dimensions before firing and multiplying by 100. The shrinkage rate and the shrinkage start temperature can be obtained from a measurement method using a thermomechanical analyzer (TMA), a measurement method shown in Examples described later, and the like.

  In FIG. 3, the shrinkage start temperature of each molded body is indicated by T1 and T2. Further, the shrinkage rates S1 and S2 are shrinkage rates of the respective molded bodies at a certain temperature T. In the present invention, the shrinkage start temperature difference ΔT of the molded body, that is, (T2−T1) is in the range of 0 to 70 ° C. Further, at a temperature at which the shrinkage rate S1 of the molded body having a shrinkage start temperature T1 (molded body having a low shrinkage start temperature) is 2%, the molded body having a shrinkage start temperature T2 (a molded body having a high shrinkage start temperature). The shrinkage rate difference ΔS, that is, (S1−S2) is in the range of 0 to 1.5%. In this way, by controlling the behavior of each molded body in the initial stage of shrinkage, it is possible to suppress the occurrence of warpage and obtain an oxygen sensor element with a small warpage.

  In order to further reduce the amount of warpage of the oxygen sensor element, it is preferable to adjust the shrinkage rate difference ΔS within the following predetermined range. That is, at a temperature at which the shrinkage rate S1 of the molded body with the shrinkage start temperature T1 is 1.5%, the shrinkage rate difference ΔS with the molded body with the shrinkage start temperature T2 is set in the range of 0 to 1%. Thereby, the warpage suppressing effect is further improved, and an oxygen sensor element in which the amount of warpage is further reduced can be obtained.

  Hereinafter, the manufacturing method of the oxygen sensor element according to the present embodiment will be described based on the exploded perspective view of FIG. First, an unfired solid electrolyte layer molded body 12 is produced using a known molding method such as a doctor blade method for producing a green sheet. Next, unsintered molded bodies 15a, 15b, 15c for the insulating base are produced using the same molding method. Furthermore, the molded body 16 for the porous protective layer is produced by the same molding method as described above.

  Different ceramic materials are used for the molded body 12 and the molded bodies 15a, 15b, and 15c. The shrinkage start temperature difference ΔT and the shrinkage rate difference ΔS during firing of the molded body 12 and the molded bodies 15a, 15b, and 15c are set within the range of the above conditions. Since the porous protective layer is a porous body, the influence of the shrinkage start temperature and shrinkage rate of the porous protective layer molded body 16 on the warpage of the oxygen sensor element is affected by the solid electrolyte layer molded body 12 and the insulating substrate. Compared with the shrinkage start temperature and shrinkage rate of the molded parts 15a, 15b, 15c for parts, it is very slight. Therefore, the shrinkage start temperature difference ΔT and the shrinkage rate during firing of the molded body 12 and the molded bodies 15a, 15b, and 15c are not particularly considered in regard to the shrinkage start temperature and the shrinkage ratio of the porous protective layer molded body 16. An oxygen sensor element with small warpage can be obtained simply by setting the difference ΔS within the range of the above conditions.

  The shrinkage start temperature and shrinkage rate of each molded body can be changed, for example, by changing the blending amount of an auxiliary agent such as a binder and a plasticizer blended in the molded body, or the particle size of the ceramic material (ceramic powder) that is the main component of the molded body. It can be adjusted by changing. When the amount of the auxiliary agent is increased, the shrinkage start temperature rises and the shrinkage rate decreases. On the other hand, when the amount of the auxiliary agent is reduced, the shrinkage start temperature is lowered and the shrinkage rate is increased. Further, when the particle size of the ceramic powder is reduced, the shrinkage start temperature is lowered and the shrinkage rate is increased. On the other hand, when the particle size of the ceramic powder is increased, the shrinkage start temperature rises and the shrinkage rate decreases.

  Next, a conductive metal material and a co-material as necessary are mixed to produce a print paste for a heating element. The mixing method is not particularly limited, and for example, roll mixing such as three rolls, mill mixing using a mill, or the like can be used. Similarly, printing pastes for the lead portion, the detection electrode, the reference electrode, and the electrode pad are produced using roll mixing or the like.

  Next, the printed paste is applied to the molded body 12 by screen printing or the like and dried to form the electrode patterns of the detection electrode 13, the reference electrode 14, the lead portions 18 and 19, and the electrode pads 31 to 33. A through hole (not shown) for electrically connecting the electrode pad 32 and the electrode pad 33 is formed in the molded body 12.

  Subsequently, the heater paste of the heating element 22, the lead portion 23, and the electrode pad 34 is formed by applying the printing paste to the molded body 15c by screen printing or the like and drying it. An electrode pattern of the electrode pad 35 is formed on the back surface of the molded body 15c in the same manner as described above. A through hole (not shown) for electrically connecting the electrode pad 34 and the electrode pad 35 is formed in the molded body 15c.

  Next, a molded body 16 for the porous protective layer, a molded body 12 with an electrode pattern formed thereon, a molded body 15a punched into a U-shape with a mold, a molded body 15b, and a molded body 15c with a heater pattern formed thereon. The green body (laminated body in which each molded body is laminated) is obtained by positioning and closely laminating. In order to adjust the thickness of the oxygen sensor element, there is no problem even if another molded body (green sheet) on which various patterns are not printed is further interposed between the molded bodies. Absent.

  Next, the laminated body can be cut into predetermined dimensions as necessary, fired and integrated to obtain an oxygen sensor element. The firing temperature can be appropriately selected depending on the ceramic material, the electrode material, and the like, and is usually about 1300 to 1600 ° C. By simultaneously firing the respective members as described above, the firing can be performed once, and the cost can be reduced.

It should be noted that the configuration of the oxygen sensor element is not limited to the above embodiment without departing from the object of the present invention. For example, in the above embodiment, the case where the present invention is applied to an oxygen sensor element has been described. However, the present invention can also be applied to a gas sensor used for a gas sensor element having a similar structure, such as a NOx sensor or a CO ₂ sensor. is there.

  In addition, the ceramic molded body joining method of the present invention is not limited to the case of manufacturing the gas sensor element as described above, but various uses for manufacturing a laminated sintered body by firing and integrating a plurality of different ceramic molded bodies. It can be similarly applied to.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further in detail, this invention is not limited to a following example.

[Examples 1, 2, 4, 5 and Comparative Example 1]
First, a butyral binder, a plasticizer and a solvent were mixed with zirconia powder having an average particle size of 0.7 μm and stirred for 48 hours to obtain a slurry. At that time, the addition amount of the binder was adjusted in a range of 8 to 20% by mass with respect to 100 parts by mass of the zirconia powder. Then, the said slurry was shape | molded by doctor blade shaping | molding, it was made to dry, and the molded object for solid electrolyte layers of thickness 180 micrometers whose shrinkage start temperature was adjusted to the value shown in Table 1 was produced, respectively.

  On the other hand, a butyral binder, a plasticizer and a solvent were mixed with alumina powder having an average particle diameter of 0.6 μm and stirred for 48 hours to obtain a slurry. At that time, the addition amount of the binder was adjusted in a range of 10 to 25% by mass with respect to 100 parts by mass of the alumina powder. Thereafter, the slurry was molded and dried by doctor blade molding, and a molded body for an insulating base part having a thickness of 200 μm and a shrinkage start temperature adjusted to the value shown in Table 1 was produced.

  Further, an organic pore material, a butyral binder, a plasticizer and a solvent were mixed with alumina powder having an average particle diameter of 1.0 μm, and stirred for 24 hours to obtain a slurry. Thereafter, the slurry was molded by doctor blade molding and dried to produce a molded body for a porous protective layer having a thickness of 120 μm.

  Next, a predetermined amount of alumina powder, butyral binder, and terpineol having an average particle diameter of 1.0 μm is prepared in platinum powder having an average particle diameter of 0.5 μm, and after 10 passes of mixing with three rolls, terpineol is used. Dilution and viscosity adjustment were performed to obtain a heater pattern printing paste.

  In addition, platinum powder with an average particle size of 0.5 μm was mixed with zirconia powder with an average particle size of 0.7 μm, butyral binder and terpineol, mixed 10 times with 3 rolls, diluted with terpineol, The viscosity-adjusted detection electrode printing paste, reference electrode printing paste, electrode pad printing paste, and lead portion printing paste were obtained.

  Next, a heater pattern printing paste was formed on the molded body for the insulating substrate by screen printing and dried to obtain a molded body on which the heater pattern was formed. Next, through holes were formed in the molded body by punching, and after filling with a conductive paste, an electrode pad pattern was formed. Further, in order to form a hollow portion having a width of 1.6 mm, a molded body for the insulating base portion was punched out with a mold to obtain a U-shaped molded body.

  On the other hand, on the front and back surfaces of the molded body for the solid electrolyte layer, a printing paste for the detection electrode, the reference electrode, and the lead portion was formed by screen printing and dried to obtain a molded body on which the electrode pattern was formed. . Next, through holes were formed in the molded body by punching, and after filling with a conductive paste, an electrode pad pattern was formed.

Thereafter, each molded body obtained above was positioned, laminated by thermocompression bonding, and pressed under pressure to obtain a green body (laminated body). Subsequently, this laminated body was cut into a predetermined shape with a hot knife to obtain an oxygen sensor element molded body. And this oxygen sensor element molded object was baked on the following baking conditions, and each oxygen sensor element was produced.
Firing conditions: Temperature rise from room temperature to 500 ° C. in 6 hours, hold at 500 ° C. for 1 hour, temperature rise from 500 ° C. to 800 ° C. in 2 hours, temperature rise from 800 ° C. to 1450 ° C. in 7 hours, temperature at 1450 ° C. for 2 hours Retention

The shrinkage start temperature and shrinkage rate of the molded body for the solid electrolyte layer and the molded body for the insulating base were measured as follows. First, shrinkage behavior measurement compacts having a width of 7 mm, a length of 60 mm, and a thickness of 200 μm were prepared in the same composition as the solid electrolyte layer molded body and the insulating base body molded body used in the examples and comparative examples. The length of the molded body before firing was measured. Subsequently, in order to investigate the relationship between the shrinkage rate and the temperature of each molded body, a firing pattern in which firing was stopped at a certain temperature, quenched and measured for length was repeated 15 times while changing the temperature at which firing was stopped. The shrinkage rate at each temperature was calculated from the dimensional data using the following formula, and shrinkage curves representing the relationship between the shrinkage rate and temperature as shown in FIG. 3 were obtained. In the firing pattern, for the temperature rise from room temperature to the temperature at which firing was stopped, conditions according to the temperature rise rate and holding time shown in the firing conditions when actually producing the oxygen sensor element were used. The shrinkage start temperature was the temperature at which the shrinkage rate reached 0.05%.

[Examples 3 and 6]
A butyral binder, a plasticizer and a solvent were mixed with titania powder having an average particle diameter of 1.0 μm and stirred for 48 hours to obtain a slurry. At that time, the addition amount of the binder was adjusted in a range of 9 to 23% by mass with respect to 100 parts by mass of titania powder. Then, the said slurry was shape | molded by doctor blade shaping | molding, it was made to dry, and the molded object for solid electrolyte layers of thickness 180 micrometers whose shrinkage start temperature was adjusted to the value shown in Table 1 was produced, respectively.

  On the other hand, a fortyrite powder having an average particle size of 0.8 μm was mixed with a butyral binder, a plasticizer and a solvent, and stirred for 48 hours to obtain a slurry. At that time, the addition amount of the binder was adjusted in a range of 10 to 25% by mass with respect to 100 parts by mass of the forsterite powder. Thereafter, the slurry was molded and dried by doctor blade molding, and a molded body for an insulating base part having a thickness of 200 μm and a shrinkage start temperature adjusted to the value shown in Table 1 was produced.

Otherwise, an oxygen sensor element molded body was produced in the same manner as in Example 1, and this oxygen sensor element molded body was fired at 1400 ° C. for 2 hours to produce oxygen sensor elements.

<Performance evaluation>
The state of occurrence of warpage before and after the firing of each oxygen sensor element was evaluated. FIG. 4 is a schematic diagram showing a method for evaluating the amount of warpage of the oxygen sensor element. As shown in FIG. 4, when the thickness in the stacking direction of the oxygen sensor element is H1, and the maximum height in the vertical direction when the oxygen sensor element is placed on the horizontal plate is H2, the difference between H2 and H1 ( ΔH = (H2−H1)) was defined as the amount of warpage. The results are shown in Table 1.

  From Table 1, the measurement is such that the shrinkage start temperature difference ΔT between the molded body for the insulating base portion and the molded body for the solid electrolyte layer is 80 ° C., and the shrinkage rate S2 of the molded body for the insulating base portion is 2%. In Comparative Example 1 in which the shrinkage ratio difference ΔS at the temperature T is 1.9%, it can be seen that the warpage amount ΔH is a large value of 200 μm.

  On the other hand, Example 1 in which the shrinkage start temperature difference ΔT is within 70 ° C. and the shrinkage rate difference ΔS at the measurement temperature T at which the shrinkage rate S2 of the molded body for the insulating base portion is 2% is within 1.5%. In .about.3, the warp amount .DELTA.H is suppressed to as small as 80 .mu.m or less. Example 4 in which the shrinkage start temperature difference ΔT is within 70 ° C., and the shrinkage rate difference ΔS at the measurement temperature T at which the shrinkage rate S2 of the molded body for the insulating base portion is 1.5% is within 1%. In .about.6, the warp amount .DELTA.H is further reduced to 50 .mu.m or less.

It is sectional drawing which shows a cross section perpendicular | vertical to the longitudinal direction of the oxygen sensor element manufactured using the joining method of the ceramic molded body of this invention. It is a disassembled perspective view for demonstrating the structure of the oxygen sensor element of FIG. It is a graph showing the relationship between the temperature at the time of baking, and the shrinkage rate of a molded object. It is the schematic for demonstrating the evaluation method of the curvature amount of the oxygen sensor element in an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Sensor part 12 Solid electrolyte layer 13 Detection electrode 14 Reference electrode 15 Insulating base | substrate part 16 Porous protective layer 17 Cavity part 18, 19 Lead part 21 Heater 22 Heating element 23 Lead part

Claims (4)

A method of joining ceramic molded bodies in which molded bodies made of different ceramic materials are laminated, and the laminated bodies are fired and integrated.
The shrinkage start temperature difference ΔT at the time of firing the molded body made of different ceramic materials is within 70 ° C.,
A method for joining ceramic molded bodies, characterized in that a shrinkage ratio difference ΔS with a molded body having a high shrinkage start temperature is within 1.5% at a temperature at which the molded body having a low shrinkage starting temperature is 2%. . A method of joining ceramic molded bodies in which molded bodies made of different ceramic materials are laminated, and the laminated bodies are fired and integrated.
The shrinkage start temperature difference ΔT during firing of the molded body made of different ceramic materials is within 70 ° C.,
A method for joining ceramic molded bodies, characterized in that a shrinkage ratio difference ΔS with a molded body having a high shrinkage start temperature is within 1% at a temperature at which the molded body having a low shrinkage starting temperature is 1.5%. .   The joining method according to claim 1 or 2, wherein one ceramic material is zirconia ceramics and the other ceramic material is alumina ceramics. The joining method according to any one of claims 1 to 3, wherein one of the molded bodies made of different ceramic materials is a molded body for a solid electrolyte layer, and the other is a molded body for an insulating base portion. Method for manufacturing gas sensor element using

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