JP2010181252A - Method for manufacturing ceramic sheet and method for manufacturing ceramic laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a ceramic sheet for suppressing deformation and a dimensional variation independently of a material used to obtain an excellent ceramic sheet with high quality in dimensional precision and a method for manufacturing a ceramic laminate. <P>SOLUTION: The method for manufacturing the ceramic sheet includes the step of (step of measuring the contraction rate of printing and drying) printing and drying a paste material after forming a ceramic sheet using a sheet material to dry it and determining the relationship (graph a, b) between the additional amount of a dispersing agent for the sheet material and the contraction rate of printing and drying of the ceramic sheet, the step of (step of selecting the contraction rate of printing and drying of a dispersing agent) determining an minimum point p1 that the contraction rate of printing and drying is minimized from the relationship (graph a, b) and selecting a definite range of the additional amount of a dispersing agent including an additional amount of a dispersing agent at a minimum point p1, the step of (step of forming a sheet) forming the ceramic sheet using a sheet material with the additional amount of the dispersing agent that is set in a range of the additional amount of the dispersing agent, and the step of (step of printing) printing the ceramic sheet with the paste material to dry. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a ceramic sheet used for a gas sensor element and the like, and a method for producing a ceramic laminate using a ceramic sheet obtained by the production method.

An air fuel consumption sensor, a nitrogen oxide sensor, and the like have been developed as gas sensors used for detection and measurement of gas components in exhaust gas of an internal combustion engine such as an automobile.
A gas sensor element incorporated in such a gas sensor is generally constituted by a ceramic laminate in which a plurality of layers made of ceramics such as alumina and zirconia are laminated.

  The ceramic laminate constituting the gas sensor element is composed of a ceramic sheet, a ceramic sheet formed using a sheet material containing a ceramic material, a solvent, a plasticizer, a binder, a dispersant, etc. A paste material for forming a heater or the like or for absorbing a step is printed and dried. And it is produced by laminating | stacking the ceramic sheet which printed the paste material, joining by thermocompression bonding, and baking integrally (refer patent documents 1-3 etc.).

Japanese Patent Laid-Open No. 7-336052 JP 2002-293647 A JP 2004-172591 A

  In recent years, the structure of the gas sensor element has become complicated, and the number of times of printing and drying the paste material on the ceramic sheet has increased in the manufacturing process of the ceramic laminate. When the paste material is printed and dried, the ceramic sheet swells and shrinks. Therefore, the number of times of printing and drying increases, which causes a problem that the ceramic sheet is deformed and has a dimensional change. When a plurality of such ceramic sheets are laminated, deviation occurs, and the finally obtained ceramic laminate may become a manufacturing defect.

  As a cause of deformation, dimensional change and the like of the ceramic sheet, when the paste material is printed on the ceramic sheet, the solvent in the paste material dissolves the binder in the ceramic sheet. Thereby, the arrangement of the ceramic particles in the ceramic sheet is disturbed. Then, when the paste material is dried, the solvent in the ceramic sheet evaporates, and the ceramic particles wrapped in the dissolved binder are rearranged so as to fill the gaps, thereby deforming the ceramic sheet, changing dimensions, etc. It is thought to occur.

  Therefore, in order to solve the above problem, the solvent used in the paste material is made difficult to dissolve the binder in the ceramic sheet, thereby suppressing swelling and shrinkage of the ceramic sheet during printing and drying of the paste material. Has been done. However, in this case, when the ceramic sheets laminated thereafter are thermocompression bonded, the adhesion may be reduced. In addition, this may cause warpage, peeling, cracking, or the like of the sheet when the ceramic sheet is fired.

  For this reason, there is a need for a method for producing a ceramic sheet that is not affected by the materials used for the ceramic sheet or paste material, and that does not cause deformation, dimensional change, etc. due to printing and drying of the paste material on the ceramic sheet. It is rare. And if the manufacturing method of such a ceramic sheet is established, by using the ceramic sheet obtained by the manufacturing method, a high-quality ceramic laminate having excellent dimensional accuracy can be obtained, and further, a gas sensor element It can be expected to improve the quality and performance of the product.

  The present invention has been made in view of such conventional problems, and is capable of suppressing deformation, dimensional change, etc. without depending on the material used, and obtaining a high-quality ceramic sheet with excellent dimensional accuracy. An object of the present invention is to provide a method for producing a ceramic sheet, and a method for producing a ceramic laminate using the ceramic sheet obtained by the production method.

According to a first aspect of the present invention, a ceramic sheet is formed using a sheet raw material containing at least a ceramic raw material, a solvent, a plasticizer, a binder, and a predetermined amount of a dispersant, and then dried. The paste material is printed and dried, and the amount of the dispersant added to the sheet material and the shrinkage of the ceramic sheet after drying the paste material on the basis of before the paste material is printed A printing drying shrinkage rate measuring step for obtaining a relationship with a printing drying shrinkage rate that is a rate;
From the relationship between the dispersant addition amount obtained in the print drying shrinkage rate measurement step and the print drying shrinkage rate, the minimum point at which the print drying shrinkage rate is minimized is obtained, and a constant dispersion including the dispersant addition amount at the minimum point is obtained. Dispersing agent addition amount selection process for selecting the agent addition amount range;
A sheet forming step of forming and drying the ceramic sheet using the sheet raw material in which the amount of the dispersant added is within the range of the dispersant addition amount selected in the dispersant addition amount selection step;
And a printing step of printing the paste material on the ceramic sheet and drying it (Claim 1).

The second invention is a method for producing a ceramic laminate formed by laminating a plurality of ceramic sheets produced by the method for producing a ceramic sheet of the first invention, and integrally firing the laminate.
A laminating step of laminating a plurality of the ceramic sheets;
A crimping step of crimping the plurality of laminated ceramic sheets;
A method of manufacturing a ceramic laminate, comprising: firing a plurality of the ceramic sheets that have been press-bonded together to produce the ceramic laminate (claim 6).

  In the method for producing a ceramic sheet of the first invention, in the printing drying shrinkage rate step and the dispersant addition amount selection step, a relationship between the dispersant addition amount and the printing drying shrinkage rate is obtained, and the printing drying shrinkage is determined from the relationship. The minimum point at which the rate is minimum is obtained, and a certain dispersant addition amount range including the dispersant addition amount at the minimum point is selected. And by adjusting the additive amount of the dispersant based on the selected dispersant addition amount range, and performing the sheet process and the printing process, deformation, dimensional change, etc. during the manufacturing process are suppressed, and dimensional accuracy is excellent. A high quality ceramic sheet can be obtained.

  Here, the point to be noted in the present invention is that the print drying shrinkage rate of the ceramic sheet changes by adjusting the amount of the dispersant added to the sheet raw material, which is the raw material of the ceramic sheet, and the amount of the dispersant added is specified. It is found that it can be kept low by adjusting to a certain range (dispersant addition amount range) including the dispersant addition amount that is a minimum point in the relationship between the additive addition amount and the printing drying shrinkage ratio. That is.

  And in this invention, before producing the target ceramic sheet, a ceramic sheet is preliminarily produced, and the amount of dispersant added that can keep the swelling and shrinkage of the ceramic sheet low during printing and drying of the paste material Is selected in advance. By producing the target ceramic sheet after going through such a process, it is possible to always suppress deformation, dimensional change, etc. during the manufacturing process without depending on the material used, and excellent in dimensional accuracy. A high quality ceramic sheet can be obtained.

As described above, the reason why the print drying shrinkage rate of the ceramic sheet can be reduced and the deformation, dimensional change, and the like can be suppressed by setting the dispersant addition amount in the specific range is as follows. It is done.
That is, it is considered that the ceramic particles in the ceramic sheet are uniformly dispersed and the ceramic particles are packed in a densely arranged state by setting the amount of the dispersant added in the above specific range. For this reason, it is considered that swelling and shrinkage of the ceramic sheet can be suppressed as much as possible during printing and drying of the paste material, thereby suppressing deformation, dimensional change, and the like.

  For example, as has been a problem in the past, even when the paste material is printed, even if the solvent in the paste material dissolves the binder in the ceramic sheet, the disturbance in the arrangement of the ceramic particles can be minimized. . Therefore, when the paste material is dried, even if the solvent in the ceramic sheet evaporates, rearrangement of the ceramic particles hardly occurs. Thereby, swelling and shrinkage of the ceramic sheet can be suppressed, and as a result, deformation, dimensional change and the like of the ceramic sheet can be suppressed.

  Thus, according to the manufacturing method of the first invention, it is possible to suppress deformation, dimensional change, etc. without depending on the material to be used, and to obtain a high-quality ceramic sheet with excellent dimensional accuracy. Can do.

  Moreover, the manufacturing method of the ceramic laminated body of the said 2nd invention produces a ceramic laminated body using the ceramic sheet manufactured by the manufacturing method of the ceramic sheet of the said 1st invention. That is, a ceramic laminate is manufactured using a high-quality ceramic sheet with excellent dimensional accuracy. Therefore, generation | occurrence | production of the malfunction in a manufacturing process, for example, generation | occurrence | production of the shift | offset | difference at the time of lamination | stacking of a ceramic sheet, the curvature at the time of baking, peeling, a crack, etc. can be suppressed. Thereby, the high quality ceramic laminated body excellent in dimensional accuracy can be obtained.

FIG. 3 is an explanatory diagram showing the relationship between the added amount of dispersant and the printing drying shrinkage rate in Example 1. FIG. 3 is an explanatory diagram showing the relationship between the amount of dispersant added and the density in Example 1. FIG. 6 is a perspective development view of a gas sensor element in Example 2. Sectional explanatory drawing of the gas sensor element in Example 2. FIG.

In the first invention, as the ceramic raw material among the sheet raw materials, general ceramic powder such as alumina and zirconia can be used.
The ceramic sheet can be formed by using a doctor blade method, an extrusion method, an injection molding method, a uniaxial pressure molding method, or the like.

Further, as the paste material, a material in which a solvent, a binder, or the like is mixed with ceramic or metal powder as a main component can be used.
The paste material may be used not only in one type but also in a plurality of types in accordance with the ceramic sheet to be produced. The paste material may be printed not only once but also a plurality of times. In addition, when printing a plurality of times, drying is performed each time printing is performed.

  In the dispersion addition amount selecting step, the print drying shrinkage rate is defined as x for the ceramic sheet before printing the paste material, y for the ceramic sheet after drying the paste material, and print drying shrinkage. The rate z (%) = {(xy) / x} × 100. Note that “after the paste material has been dried” means after all the printed paste materials have been dried.

In the dispersant addition amount selection step, the minimum point at which the print drying shrinkage rate is minimized is determined from the relationship between the dispersant addition amount and the print drying shrinkage rate. Here, the minimum point means a point at which the printing drying shrinkage rate changes from decrease to increase.
In addition, in the dispersant addition amount selection step, a certain dispersant addition amount range including the dispersant addition amount at the minimum point is selected. For this purpose, the dispersant addition amount at the minimum point is set as the dispersant addition amount range. It is also included. Further, when the minimum point is not clear, a certain range near the minimum point may be selected as the dispersant addition amount range.

Further, as the dispersant, it is preferable to use a dispersant in which the graph showing the relationship is downwardly convex (for example, see FIG. 1 in Example 1) in the relationship between the additive amount of the dispersant and the printing drying shrinkage rate. In addition, it is preferable to use one having the above-mentioned minimum point in the range of 2.5 to 4.5% by weight of the dispersant addition amount.
In this case, the minimum point at which the print drying shrinkage rate is minimized can be easily obtained, and further, the dispersant addition amount range can be easily selected.

Further, as the dispersant, it is preferable to use a dispersant capable of setting the printing drying shrinkage rate at the minimum point to 0.1% or less (claim 2). Further, it is more preferable to use a printing drying shrinkage rate at the minimum point of 0.05% or less.
In this case, the deformation, dimensional change, etc., of the ceramic sheet during printing and drying of the paste material can be suppressed more reliably.

The range of the dispersant addition amount is preferably in the range of the dispersant addition amount ± 0.5% by weight at the minimum point (Claim 4).
In this case, it is possible to reliably obtain the effect of suppressing deformation, dimensional change, etc. of the ceramic sheet during printing and drying of the paste material. The above-mentioned range of the added amount of the dispersant may be adjusted according to the relationship between the printing drying shrinkage ratio and the added amount of the dispersant, the minimum point in the relationship, the type of the dispersant, and the like.

The dispersant is preferably an acrylic dispersant (claim 5).
In this case, the print drying shrinkage rate of the ceramic sheet can be further reduced. Therefore, it is possible to effectively exhibit the effect of suppressing deformation, dimensional change, and the like of the ceramic sheet during printing and drying of the paste material.
As the acrylic dispersant, for example, Kyoeisha Chemical DOPA series, Enomoto Kasei ED series, and the like can be used.

In the second invention, the ceramic laminate can be used for a gas sensor element.
In this case, it is possible to more remarkably exhibit the excellent characteristics of the ceramic laminate, such as excellent dimensional accuracy and high quality. That is, gas sensors are increasingly miniaturized in recent years and are used in higher temperature environments. Therefore, more excellent dimensional accuracy and durability are required. Therefore, if the ceramic laminate having excellent dimensional accuracy and high quality is applied to the gas sensor element, the gas sensor can be miniaturized and the durability can be improved.

Example 1
The manufacturing method of the ceramic sheet concerning the Example of this invention is demonstrated.
The method for producing a ceramic sheet of the present example includes forming a ceramic sheet using a sheet raw material containing at least a ceramic raw material, a solvent, a plasticizer, a binder, and a predetermined amount of a dispersant, and then drying the ceramic sheet. It is the shrinkage rate of the ceramic sheet after the paste material is dried on the basis of the amount of the dispersant added to the sheet material and the paste material printed before the paste material is printed and dried. A print drying shrinkage rate measurement step for obtaining a relationship with the print drying shrinkage rate (graphs a and b in FIG. 1) is performed.

Next, from the relationship (graphs a and b in FIG. 1) between the dispersant addition amount obtained in the print drying shrinkage measurement step and the print drying shrinkage (graphs a and b), the minimum point (p1) at which the print drying shrinkage is minimized is obtained. A dispersant addition amount selection step is performed for selecting a certain dispersant addition amount range including the dispersant addition amount at the minimum point (p1). Next, a sheet forming step is performed in which the ceramic sheet is formed and dried using the sheet raw material in which the amount of the dispersant added is within the range of the dispersant addition amount selected in the dispersant addition amount selection step. Next, a printing process is performed in which the paste material is printed on the ceramic sheet and dried.
This will be described in detail below.

<Print drying shrinkage measurement process>
First, alumina powder as a ceramic raw material is mixed with a predetermined amount of butanol as a solvent, isobutyl acetate and a predetermined dispersing agent, and further, a predetermined amount of BBP as a plasticizer and PVB as a binder are mixed to obtain a slurry sheet raw material. Was made. In this example, an acrylic dispersant (dispersant A, B) was used as a dispersant, and a plurality of sheet raw materials with different amounts of the dispersant were prepared. The addition amount of the dispersant was 0 to 8% by weight.
And after making this sheet | seat raw material into a predetermined viscosity by vacuum defoaming, it shape | molded by the doctor blade method and dried, and produced the ceramic sheet | seat.

Next, terpineol as a solvent and PVB or ethylcellulose as a binder were mixed with alumina powder as a main component to prepare a paste-like paste material. The paste material was printed on a ceramic sheet and dried. In this example, the paste material was printed and dried three times.
At this time, the print drying shrinkage ratio of the ceramic sheet was determined. The print drying shrinkage ratio is x, the dimension of the ceramic sheet before printing the paste material, y is the dimension of the ceramic sheet after all the printed paste material is dried, and the print drying shrinkage ratio z (%) = {( xy) / x} × 100.

Subsequently, the relationship between the amount of the dispersant added in the raw material for the ceramic sheet and the print drying shrinkage of the ceramic sheet was determined, and a graph was prepared.
The created graph is shown in FIG. In the figure, the horizontal axis represents the amount of dispersant added (% by weight), and the vertical axis represents the printing drying shrinkage rate (%). Graph a is an example using Dispersant A, and graph b is an example using Dispersant B.

<Dispersant addition amount selection process>
Next, from the graphs a and b in FIG. 1 in which the relationship between the added amount of the dispersant and the print drying shrinkage was obtained, the minimum point at which the print drying shrinkage was minimized was obtained. Here, the minimum point refers to a point where the print drying shrinkage rate changes from decrease to increase in the graphs a and b showing the relationship between the added amount of the dispersant and the print dry shrinkage rate.

  As shown in the figure, the graphs a and b have a downwardly convex shape, and the print drying shrinkage rate decreases to a certain point, and increases beyond a certain point. Therefore, the point at which the print drying shrinkage ratio changes from decrease to increase was determined as the minimum point p1. In this example, the graph a becomes the minimum point p1 when the dispersant addition amount is 3.0% by weight. Graph B is the minimum point p1 when the dispersant addition amount is 4.0% by weight.

Next, from the graphs a and b in FIG. 1, the dispersant addition amount range when the dispersant A and the dispersant B were used was selected. Here, the dispersant addition amount range is a certain range of the dispersant addition amount including the dispersant addition amount at the minimum point p1 obtained previously.
In this example, the dispersant addition amount range when the dispersant A is used is 2.5 to 3.5 wt%. Further, the dispersant addition amount range when the dispersant B was used was set to 3.5 to 4.5% by weight.

<Sheet forming process>
Next, in the same manner as in the printing drying shrinkage rate step, a predetermined amount of a solvent and a dispersant are mixed with alumina powder as a ceramic raw material, and a predetermined amount of a plasticizer and a binder are further mixed to prepare a slurry-like sheet raw material. . At this time, the additive amount of the dispersant was set within the dispersant additive amount range selected in the dispersant additive amount selecting step. And after making this sheet | seat raw material into a predetermined viscosity by vacuum defoaming, it shape | molded by the doctor blade method and dried, and produced the ceramic sheet | seat.

<Printing process>
Next, in the same manner as in the printing drying shrinkage rate step, a predetermined amount of a solvent and a binder were mixed with the alumina powder as the main component to prepare a paste-like paste material. The paste material was printed on a ceramic sheet and dried. In this example, the paste material was printed and dried three times.
Thus, a ceramic sheet was produced.

Next, the effect in the manufacturing method of the ceramic sheet of this example is demonstrated.
In the method for producing a ceramic sheet of this example, in the printing drying shrinkage rate step and the dispersant addition amount selection step, the relationship between the dispersant addition amount and the printing drying shrinkage rate (graphs a and b in FIG. 1) is obtained. From the relationship (graphs a and b in FIG. 1), the minimum point (p1) at which the print drying shrinkage rate is minimized is obtained, and a constant dispersant addition amount range including the dispersant addition amount at the minimum point (p1) is selected. To do. And by adjusting the additive amount of the dispersant based on the selected dispersant addition amount range and performing the sheet process and the printing process, deformation, dimensional change, etc. during the manufacturing process are suppressed, and dimensional accuracy is excellent. A high quality ceramic sheet can be obtained.

  Here, the point to be noted in this example is that, as shown in FIG. 1, the print drying shrinkage ratio of the ceramic sheet is changed by adjusting the amount of dispersant added to the raw material of the ceramic sheet (graph a, b), a certain range including the amount of the dispersant to be added in a certain range, that is, the amount of the dispersant to be the minimum point p1 in the relationship between the amount of the dispersant added and the printing drying shrinkage (the amount of the dispersant added) It has been found that it can be kept low by adjusting to (range).

  And in this example, before producing the target ceramic sheet, the ceramic sheet is preliminarily produced, and the amount of dispersant added that can keep the swelling and shrinkage of the ceramic sheet low during printing and drying of the paste material Is selected in advance. By producing the target ceramic sheet after going through such a process, it is possible to always suppress deformation, dimensional change, etc. during the manufacturing process without depending on the material to be used, and excellent in dimensional accuracy. A high quality ceramic sheet can be obtained.

As described above, the reason why the print drying shrinkage rate of the ceramic sheet can be reduced and the deformation, dimensional change, and the like can be suppressed by setting the dispersant addition amount in the specific range is as follows. It is done.
That is, it is considered that the ceramic particles in the ceramic sheet are uniformly dispersed and the ceramic particles are packed in a densely arranged state by setting the amount of the dispersant added in the above specific range. For this reason, it is considered that swelling and shrinkage of the ceramic sheet can be suppressed as much as possible during printing and drying of the paste material, thereby suppressing deformation, dimensional change, and the like.

  For example, as has been a problem in the past, even when the paste material is printed, even if the solvent in the paste material dissolves the binder in the ceramic sheet, the disturbance in the arrangement of the ceramic particles can be minimized. . Therefore, when the paste material is dried, even if the solvent in the ceramic sheet evaporates, rearrangement of the ceramic particles hardly occurs. Thereby, swelling and shrinkage of the ceramic sheet can be suppressed, and as a result, deformation, dimensional change and the like of the ceramic sheet can be suppressed.

Note that when the additive amount of the dispersant is reduced below the above specific range, the printing drying shrinkage ratio is increased because the aggregation of the ceramic particles in the ceramic sheet increases, and the ceramic particles are reduced during printing and drying of the paste material. It is thought that this is because it becomes easy to cause rearrangement.
In addition, when the amount of the dispersant added is increased beyond the above specific range, the printing drying shrinkage ratio is increased because the excess dispersing agent enters between the ceramic particles, and the paste material is printed and dried. This is probably because the fluidity of the particles is improved to promote rearrangement.

In order to confirm the above effect, the relationship between the amount of dispersant added and the density of the ceramic sheet was determined and a graph was prepared.
The created graph is shown in FIG. In the figure, the horizontal axis represents the amount of dispersant added (% by weight), and the vertical axis represents the density (g / cc). Graph a is an example using Dispersant A, and graph b is an example using Dispersant B.

As shown in the figure, the density of the ceramic sheet increases as the amount of dispersant added increases. This is because aggregation of the ceramic particles in the ceramic sheet decreases as the amount of the dispersant added increases. And when a dispersing agent addition amount exceeds a certain point (p2), the increase in density becomes extremely small. This is because the dispersant becomes excessive and is filled between the ceramic particles.
Therefore, when the dispersant addition amount at the point p2 where the increase in density becomes extremely small is considered, it can be considered that the ceramic particles in the ceramic sheet are packed most densely.

  Further, when FIG. 2 is compared with FIG. 1, the dispersant addition amount at the point p <b> 2 where the increase in density becomes extremely small is substantially equal to the dispersant addition amount at the minimum point p <b> 1. Therefore, the ceramic particles in the ceramic sheet are densely packed, so that the ceramic sheet is less likely to swell and shrink, the ceramic particles are rearranged, and the print drying shrinkage rate of the ceramic sheet can be kept low. Can be considered.

  Therefore, by setting the added amount of the dispersant within the above specific range, the ceramic particles in the ceramic sheet are packed in a closely arranged state, and the swelling and shrinkage of the ceramic sheet are suppressed as much as possible when the paste material is printed and dried. As a result, it was confirmed that deformation, dimensional change and the like can be suppressed.

  Thus, according to the manufacturing method of this example, deformation, dimensional change, etc. can be suppressed without depending on the material used, and a high-quality ceramic sheet with excellent dimensional accuracy can be obtained.

(Example 2)
In this example, the method for producing a ceramic sheet of the present invention is installed in an exhaust pipe of an internal combustion engine for various vehicles such as an automobile engine, for example, to produce a gas sensor element incorporated in an oxygen sensor for measuring the oxygen concentration in exhaust gas. It is an example applied to.

  As shown in FIGS. 3 and 4, the gas sensor element 2 of this example has an oxygen ion conductive solid electrolyte body 24 made of zirconia, and has an opening 220 on the surface of the solid electrolyte body 24. In addition, a dense insulating layer 22 made of alumina and impermeable to gas is provided. Further, between the solid electrolyte body 24 and the insulating layer 22, a measurement gas side electrode 23 made of platinum, a lead portion 231 and a terminal portion 232 connected thereto are provided.

As shown in FIG. 3, a gas chamber forming layer 29 to be measured is laminated on the solid electrolyte body 24. The measured gas chamber forming layer 29 is made of alumina that is electrically insulating and dense and does not transmit gas, and is provided with an opening 290 that constitutes the measured gas chamber 210.
A shielding layer 20 made of dense and gas-sealing alumina is laminated on the gas chamber forming layer 29 to be measured.

  Further, the measured gas chamber forming layer 29 and the shielding layer 20 are formed so as to cover the lead portion 231 continuous with the measured gas side electrode 23. As a result, the shielding layer 20 made of dense ceramic and the measured gas chamber forming layer 29 are interposed between the lead portion 231 and the buffer sealing material 4.

  As shown in FIGS. 3 and 4, the porous diffusion resistance layer 21 is disposed so as to be embedded in a part of the measurement gas chamber forming layer 29. That is, the end surface 211 is exposed in a direction orthogonal to the axial direction of the gas sensor element 2 and is disposed on both sides of the opening 290 so as to sandwich the opening 290 of the measured gas chamber forming layer 29. Then, the measurement gas passes through the porous diffusion resistance layer 21 and is introduced into the measurement gas chamber 210 from the end surface 211 exposed in the short direction.

  Further, as shown in FIG. 3, a reference gas side electrode 25 made of platinum and a lead portion 251 connected thereto are formed on the surface of the solid electrolyte body 24 opposite to the side where the measured gas side electrode 23 is disposed. A terminal portion 252 is provided. The terminal portion 252 is electrically connected to the terminal portion 253 provided on the measured gas chamber 210 side through the through hole 240 filled with a conductor.

  As shown in FIGS. 3 and 4, a reference gas chamber forming layer 26 made of alumina that is electrically insulating and dense and does not allow gas to pass through is laminated on the solid electrolyte body 24. The reference gas chamber forming layer 26 is provided with a groove 261 that functions as the reference gas chamber 260. For example, outside air (air) is introduced into the reference gas chamber 260 as a reference gas.

  As shown in FIGS. 3 and 4, a heater substrate 28 made of alumina is laminated on the reference gas chamber forming layer 26. The heater substrate 28 is provided with a heating element 27 that generates heat when energized, and a lead portion 271 for energizing the heating element 27 so as to face the reference gas chamber forming layer 26, and the heating element 27 and the lead portion 271. A terminal portion 272 is provided on the surface opposite to the surface provided with the. Further, the terminal portion 272 and the lead portion 271 are electrically connected by a through hole 280 filled with a conductor.

  The gas sensor element 2 having the above-described configuration includes a shielding layer 20 made of alumina, a measured gas chamber forming layer 29 having a porous diffusion resistance layer 21, an insulating layer 22, a reference gas chamber forming layer 26, a heater substrate 28, and zirconia. It is a ceramic laminated body comprised by laminating | stacking the solid electrolyte body 24 which consists of this.

  In manufacturing the gas sensor element 2 which is such a ceramic laminate, an alumina ceramic which constitutes the shielding layer 20, the gas chamber forming layer 29, the insulating layer 22, the reference gas chamber forming layer 26, and the heater substrate 28, respectively. A zirconia ceramic sheet constituting the sheet and the solid electrolyte body 24 was produced.

At this time, the zirconia ceramic sheet to be the solid electrolyte body 24 is a paste that forms the gas side electrode 23 to be measured, the lead part 231, the terminal part 232, the reference gas side electrode 25, the lead part 251, the terminal part 252 and the terminal part 253. In order to print the material, it was produced by the method for producing a ceramic sheet of the present invention.
Moreover, the alumina ceramic sheet used as the heater substrate 28 was produced by the method for producing a ceramic sheet of the present invention in order to print a paste material for forming the heating element 27, the lead part 271 and the terminal part 272.

Thereafter, the produced alumina ceramic sheet and zirconia ceramic sheet were laminated at predetermined positions (lamination process). Then, the laminated ceramic sheets were pressure-bonded (crimping step) and integrally fired (firing step) to produce a ceramic laminate.
The ceramic laminate thus obtained was designated as gas sensor element 2.

Next, the effect in this example is demonstrated.
In this example, a ceramic laminate is produced using a ceramic sheet produced by the method for producing a ceramic sheet of the present invention. That is, a ceramic laminate is manufactured using a high-quality ceramic sheet with excellent dimensional accuracy. Therefore, generation | occurrence | production of the malfunction in a manufacturing process, for example, generation | occurrence | production of the shift | offset | difference at the time of lamination | stacking of a ceramic sheet, the curvature at the time of baking, peeling, a crack, etc. can be suppressed. Thereby, the gas sensor element 2 comprised by the high quality ceramic laminated body excellent in dimensional accuracy can be obtained.

a, b graphs (graphs showing the relationship between the amount of dispersant added and the printing drying shrinkage)
p1 local minimum

Claims (7)

After forming and drying a ceramic sheet using a sheet raw material containing at least a ceramic raw material, a solvent, a plasticizer, a binder, and a predetermined amount of a dispersant, a predetermined paste material is printed on the ceramic sheet. Print drying shrinkage that is the shrinkage rate of the ceramic sheet after drying and drying the paste material on the basis of the amount of dispersant addition amount that is the amount of dispersant added to the sheet material and before printing the paste material Printing drying shrinkage rate measurement process to obtain the relationship with the rate,
From the relationship between the dispersant addition amount obtained in the print drying shrinkage rate measurement step and the print drying shrinkage rate, the minimum point at which the print drying shrinkage rate is minimized is obtained, and a constant dispersion including the dispersant addition amount at the minimum point is obtained. Dispersing agent addition amount selection process for selecting the agent addition amount range;
A sheet forming step of forming and drying the ceramic sheet using the sheet raw material in which the amount of the dispersant added is within the range of the dispersant addition amount selected in the dispersant addition amount selection step;
And a printing step of printing the paste material on the ceramic sheet and drying the paste material.   2. The method for producing a ceramic sheet according to claim 1, wherein the dispersant is one capable of setting the printing drying shrinkage rate at the minimum point to 0.1% or less.   2. The method for producing a ceramic sheet according to claim 1, wherein the dispersant is one capable of setting the printing drying shrinkage rate at the minimum point to 0.05% or less.   The method for producing a ceramic sheet according to any one of claims 1 to 3, wherein the dispersant addition amount range is a range of the dispersant addition amount ± 0.5 wt% at the minimum point.   The method for producing a ceramic sheet according to claim 1, wherein the dispersant is an acrylic dispersant. A method for producing a ceramic laminate formed by integrally laminating a plurality of ceramic sheets produced by the method for producing a ceramic sheet according to any one of claims 1 to 5,
A laminating step of laminating a plurality of the ceramic sheets;
A crimping step of crimping the plurality of laminated ceramic sheets;
A method for producing a ceramic laminate, comprising: firing a plurality of the ceramic sheets that have been press-bonded together to produce the ceramic laminate.   7. The method of manufacturing a ceramic laminate according to claim 6, wherein the ceramic laminate is used for a gas sensor element.

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