WO2018047784A1 - Setter for firing - Google Patents

Abstract

This setter for firing is formed from a ceramic, and comprises a front surface layer, an intermediate layer and a back surface layer. The intermediate layer has a honeycomb structure; and the density of the intermediate layer is lower than those of the front surface layer and the back surface layer. Meanwhile, the front surface layer is in the form of a flat plate, and has a thickness of from 50 μm to 2,000 μm (inclusive). In addition, the front surface layer has an open porosity of from 5% to 50% (inclusive).

Description

Setter for firing

This specification discloses the technique regarding the setter for baking. In particular, a technique relating to a ceramic setter for firing is disclosed.

When firing the object to be fired, the object to be fired is placed on a ceramic setter and the setter is placed in a firing furnace. The setter is heated together with the object to be fired in a firing furnace. A setter with a small heat capacity is required to follow the changes in the furnace temperature well. Japanese Utility Model Laid-Open No. 1-167600 (hereinafter referred to as Patent Document 1) discloses a technique in which the setter has a honeycomb structure and the heat capacity of the setter is reduced. Patent Document 1 uses a honeycomb setter to suppress heating unevenness on the upper surface (the surface not in contact with the setter) and the lower surface (the surface in contact with the setter) of the object to be fired.

As described above, when the setter has a honeycomb structure, the density of the setter is reduced, and the heat capacity of the setter can be reduced. However, typically, as the density decreases, the strength decreases. Therefore, the setter may be deformed or damaged by repeatedly using the setter. Simply setting the setter to a honeycomb structure reduces the durability of the setter. It can be said that a reduction in heat capacity and an improvement in durability are in a trade-off relationship. There is a need for a setter with a small heat capacity and high durability. The present specification provides a technique for realizing a setter having high durability while maintaining a small heat capacity.

The firing setter disclosed in the present specification is made of ceramics and includes a front surface layer, an intermediate layer, and a back surface layer. The intermediate layer has a honeycomb structure and has a lower density than the front surface layer and the back surface layer. In the setter for firing, the surface layer has a flat plate shape with a thickness of 50 μm to 2000 μm and an open porosity of 5% to 50%.

First, the “surface layer” and “back layer” in this specification will be described. The “surface layer” is a layered portion including a surface on which the object to be fired is placed, adjacent to the intermediate layer, and formed at a higher density than the intermediate layer. The “back surface layer” is a layered portion that is adjacent to the intermediate layer on the side opposite to the surface layer with respect to the intermediate layer and is formed at a higher density than the intermediate layer. Note that when the front and back surfaces of the setter for firing are used as the placement surface of the object to be fired, the expressions “surface layer” and “back surface layer” merely indicate the relative positions during firing. In this case, both the “surface layer” and the “back surface layer” have the same structural features as the “surface layer”.

In the setter for firing, the intermediate layer has a lower density than the front surface layer and the back surface layer. In other words, the front surface layer and the back surface layer have a higher density than the intermediate layer. By providing a low-density intermediate layer, the heat capacity of the entire firing setter is reduced. By providing the high-density surface layer and the back surface layer, the strength of the entire setter for firing can be maintained.

Further, by adjusting the thickness of the surface layer to 50 μm or more and 2000 μm or less, the strength of the surface layer is ensured and the weight of the object to be fired can be supported. In addition, by ensuring the strength of the surface layer, it is possible to suppress cracking and chipping of the surface layer due to impact when loading and unloading the object to be fired, and to prevent deformation of the setter during the firing process. Is done. As a result, the object to be fired is reliably held on the setter surface. For example, when firing a relatively small size object to be fired, cracking or chipping of the surface layer is suppressed, thereby preventing the object to be fired from being lost. Moreover, when baking a comparatively large-sized to-be-fired thing, it is prevented that a to-be-fired thing deform | transforms by suppressing a deformation | transformation of a setter. Further, by adjusting the surface layer to the above thickness, it is possible to suppress the heat capacity of the surface layer from becoming excessive, and to reduce the temperature difference between the setter and the object to be fired when the temperature is raised or lowered.

In general, when the density of the surface layer is increased, the porosity of the surface layer is lowered. If the porosity (especially the open porosity) of the surface layer decreases, the gas generated from the fired product will not easily escape at the contact portion between the fired product and the surface layer, and the furnace gas will not easily penetrate the surface layer. The temperature difference between the fired product and the setter becomes large. In the above setter for firing, by making the open porosity of the surface layer 5% or more, it is possible to prevent the gas generated from the fired product from becoming difficult to escape, and the atmosphere gas in the furnace easily penetrates into the surface layer. The temperature difference between the furnace temperature and the setter can be reduced. Moreover, it can also prevent that the intensity | strength of a surface layer falls by making open porosity into 50% or less. The “open porosity” is obtained by dividing pores (open holes) communicating with the outer space of the porous body by the volume of the porous body, among the pores of the porous body.

The perspective view of the setter for baking of 1st Example is shown. FIG. 2 shows a partially enlarged view of a cross section taken along line II-II in FIG. The modification of the setter for baking of 1st Example is shown. The modification of the setter for baking of 1st Example is shown. The modification of the setter for baking of 1st Example is shown. The modification of the setter for baking of 1st Example is shown. The modification of the setter for baking of 1st Example is shown. The perspective view of the setter for baking of 2nd Example is shown. FIG. 9 is a partially enlarged view of a cross section taken along line IX-IX in FIG. 8. The figure explaining the manufacturing process of the setter for baking of 2nd Example is shown. The modification of the setter for baking of 2nd Example is shown. The modification of the setter for baking of 2nd Example is shown. The perspective view of the setter for baking of 3rd Example is shown. The perspective view of the setter for baking of 4th Example is shown. The elements on larger scale of the cross section of the setter for baking of 5th Example are shown. The partial top view of the setter for baking of 5th Example is shown. The relationship between the thickness of a coating layer and each characteristic is shown.

The following summarizes the features of the technology disclosed in this specification. The items described below have technical usefulness independently.

The setter disclosed in the present specification is used for placing the object to be fired when the object to be fired is fired. The setter disclosed in this specification is made of ceramics. Although not particularly limited, the setter material may be cordierite, mullite, alumina, zirconia, silicon nitride, or silicon carbide. From the viewpoint of the material itself having a relatively low density and a low thermal expansion coefficient, the setter material is preferably cordierite.

The setter has a surface layer, an intermediate layer, and a back layer. An object to be fired is placed on the surface layer. The surface layer is flat. Specifically, the surface layer does not have an opening such as a mesh structure, a honeycomb structure, or the like, is solid, and the surface layer portion is flat. By making the surface layer into a flat plate shape, a relatively small object to be fired (for example, an electronic component) can be reliably placed on the setter.

The thickness of the surface layer is 50 μm or more and 2000 μm or less. By setting the thickness of the surface layer to 50 μm or more, the strength of the surface layer is ensured and the weight of the object to be fired can be supported. By ensuring the strength of the surface layer, it is possible to suppress cracking or chipping of the surface layer due to an impact when loading or unloading the object to be fired. Moreover, by ensuring the strength of the surface layer, the setter is prevented from being deformed in the firing step. As a result, the object to be fired is reliably held on the setter surface. For example, when firing a relatively small size object to be fired, cracking or chipping of the surface layer is suppressed, thereby preventing the object to be fired from being lost. When baking a comparatively large size object to be fired, deformation of the setter is suppressed, thereby preventing the object to be fired from being deformed. Further, by setting the thickness of the surface layer to 2000 μm or less, it is possible to prevent the heat capacity of the surface layer from becoming excessive, and the heat of the atmosphere gas in the furnace flowing through the intermediate layer is easily transmitted to the object to be fired through the surface layer. . As a result, the temperature difference between the setter and the object to be fired when raising and lowering the temperature can be reduced. Although not particularly limited, the thickness of the surface layer is preferably 100 μm or more, and more preferably 150 μm or more. The thickness of the surface layer is preferably 1000 μm or less, more preferably 500 μm or less, still more preferably 250 μm or less, and particularly preferably 200 μm or less.

The open porosity of the surface layer is 5% or more and 50% or less. By setting the open porosity of the surface layer to 5% or more, it is possible to prevent the gas generated from the fired product from becoming difficult to escape. In addition, the furnace atmosphere gas easily penetrates into the surface layer, and the temperature difference between the furnace temperature and the setter is reduced. The temperature of the contact surface of the object to be fired with the setter closely follows the furnace temperature, and the whole object to be fired can be heated uniformly. Moreover, it can prevent that the intensity | strength of a surface layer falls by making open porosity into 50% or less. Although not particularly limited, the open porosity of the surface layer is preferably 10% or more, more preferably 20% or more, and particularly preferably 30% or more. Further, the open porosity of the surface layer is preferably 45% or less, more preferably 40% or less, and particularly preferably 35% or less.

The back layer may be flat like the surface layer. Thereby, the surface of the back layer can also be used as a surface on which the object to be fired is placed. In this case, the thickness of the back surface layer may be the same as the thickness of the surface layer. Further, the thickness of the back surface layer can be made larger than the thickness of the surface layer, and the back surface layer can be used as a layer for ensuring the strength of the setter. In this case, the thickness of the back layer may be 100 μm or more and 2000 μm or less. By setting the thickness to 100 μm or more, it is possible to prevent warping of the setter due to the load of the object to be fired and the setter itself. That is, a highly durable setter is obtained. When the thickness of the front surface layer and the back surface layer is 100 μm or more, the front surface layer and the back surface layer can be used as the placement surface of the object to be fired, and a highly durable setter can be realized. From the viewpoint of realizing high durability, the thickness of the back surface layer is preferably 200 μm or more, and more preferably 300 μm or more. Further, the thickness of the back surface layer is preferably 1000 μm or less, more preferably 500 μm or less, still more preferably 400 μm or less, and particularly preferably 350 μm or less.

The open porosity of the back surface layer may be 5% or more and 50% or less, similar to the surface layer. The front surface layer and the back surface layer may be made of the same material. By setting the open porosity of the back surface layer to 5% or more, it is possible to prevent the gas generated from the fired product from becoming difficult to escape when the back surface layer is used as a mounting surface for the fired product. Moreover, the intensity | strength of a back surface layer is securable by making open porosity into 50% or less. Although not particularly limited, the open porosity of the back layer is preferably 10% or more, more preferably 20% or more, and particularly preferably 30% or more. Further, the open porosity of the back layer is preferably 45% or less, more preferably 40% or less, and particularly preferably 35% or less.

When the back layer is used as a layer for ensuring the strength of the setter, the back layer is impregnated with finely pulverized cordierite cerven, fine mullite, fine alumina, fine zirconia, fine silicon nitride, fine silicon carbide, etc. By doing so, you may improve the intensity | strength of a back surface layer. The strength of the back surface layer can be secured without increasing the thickness of the back surface layer, and a lightweight and high strength setter can be obtained.

The intermediate layer has a lower density than the front surface layer and the back surface layer. Note that the front layer and the back layer may have the same density or different densities. The intermediate layer has a honeycomb structure. The aperture ratio of the honeycomb structure constituting the intermediate layer may be 50% or more and 95% or less. That is, in the cross section orthogonal to the direction in which the opening extends, the area of the partition wall defining the opening may be 5% or more and 50% or less, and the part (void) other than the partition wall may be 50% or more and 95% or less. In addition, the open porosity of a partition may be 5% or more and 50% or less similarly to a surface layer and / or a back surface layer. For the same reason as the surface layer and / or the back layer, the open porosity of the partition wall is preferably 10% or more, more preferably 20% or more, and particularly preferably 30% or more. Further, the open porosity of the back layer is preferably 45% or less, more preferably 40% or less, and particularly preferably 35% or less.

The thickness of the partition wall defining the honeycomb structure opening may be 50 μm or more and 2000 μm or less. By setting the partition wall thickness to 50 μm or more, the partition wall strength is secured, and the strength as the honeycomb structure can be secured. By setting the partition wall thickness to 2000 μm or less, an increase in the heat capacity of the setter can be suppressed. From the viewpoint of suppressing an increase in heat capacity while securing the strength of the honeycomb structure, the partition wall thickness is preferably 60 μm or more, and more preferably 80 μm or more. The thickness of the partition wall is preferably 1000 μm or less, more preferably 500 μm or less, still more preferably 200 μm or less, and particularly preferably 100 μm or less. In addition, the thickness of a partition may be the same as the thickness of a surface layer and / or a back surface layer. If the thickness of the partition wall is the same as that of the front surface layer and the back surface layer, all of the parts constituting the setter have the same thickness, which facilitates manufacture.

The hydraulic diameter of the opening defined by the partition wall may be not less than 0.3 mm and not more than 7 mm. By setting the hydraulic diameter to 0.3 mm or more, the atmospheric gas can easily pass through the intermediate layer. Since the setter is heated or cooled from the inside by the atmospheric gas, the temperature change of the setter can easily follow the temperature change of the atmosphere in the furnace, and the temperature raising / lowering rate during firing can be set fast. By setting the hydraulic diameter to 7 mm or less, the strength of the intermediate layer as a structure can be maintained high. The hydraulic diameter is preferably 0.4 mm or more, more preferably 0.5 mm or more, and particularly preferably 0.6 mm or more. The hydraulic diameter is preferably 3 mm or less, more preferably 2 mm or less, and particularly preferably 1.5 mm or less.

The intermediate layer is provided between the front surface layer and the back surface layer. In other words, the front surface layer and the back surface layer are bonded via the intermediate layer. The front surface layer, the intermediate layer, and the back surface layer may be integrally formed. Specifically, the partition wall of the surface layer and the intermediate layer may be continuous, the partition wall of the back surface layer and the intermediate layer may be continuous, and the surface layer, the intermediate layer, and the back surface layer may be integrated. In this case, the surface layer, the intermediate layer, and the back layer are made of the same material. A setter having such a structure can be manufactured by, for example, extrusion molding.

The opening of the intermediate layer may extend in the direction connecting the front surface layer and the back surface layer (that is, the thickness direction). Alternatively, the opening may extend in a direction orthogonal to the direction connecting the front surface layer and the back surface layer (that is, a direction parallel to the front surface or the back surface). Hereinafter, the thickness direction may be referred to as a first direction, and the direction orthogonal to the first direction may be referred to as a second direction.

The form in which the opening extends in the first direction can increase the strength in the thickness direction (compressive strength) and is suitable as a setter for firing a heavy object to be fired. Further, the form in which the opening extends in the second direction is advantageous in that the integral molding is easy because the thickness of the front surface layer and the back surface layer can be easily controlled in the extrusion molding. In the form in which the opening extends in the second direction, the opening may appear only once or in a plurality of times in the first direction. That is, one or more honeycomb cells (openings surrounded by partition walls) may appear between the front surface layer and the back surface layer. In this case, the honeycomb cells may be 1 cell or more and 6 cells or less. The number of honeycomb cells can be appropriately adjusted based on the desired setter thickness, hydraulic diameter, and the like.

The setter disclosed in the present specification may have a thermal expansion coefficient of 2.0 ppm / ° C. or less, preferably 1.5 ppm / ° C. or less, more preferably 1.0 ppm / ° C. or less. “The coefficient of thermal expansion of the setter” means a surface layer, an intermediate layer (honeycomb structure layer), a back layer, and a sample in which the intermediate layer includes one or more honeycomb cells when measured from room temperature to 800 ° C. Value. Even if a bulk product formed by press molding or the like has a thermal expansion coefficient exceeding 2.0 ppm / ° C., a setter having a honeycomb structure layer (intermediate layer) is formed by extrusion molding. Thus, a setter having a thermal expansion coefficient of 2.0 ppm / ° C. or less can be obtained.

The setter disclosed in this specification may have a flat plate shape as a whole, or a rib may be provided at an in-plane end. A flat setter can be easily manufactured. By providing ribs on the setter, the strength of the setter can be supplemented. Further, by providing ribs, when a plurality of setters are loaded in the firing furnace, a spacer for securing a gap between the setters can be eliminated.

Further, the setter disclosed in the present specification may be provided with a coating layer on the front surface and / or the back surface. The coating layer can prevent a chemical reaction from occurring between the object to be fired and the setter. By applying the coating, the choice of the material of the setter or the type of the object to be fired can be increased. Moreover, the smoothness of the setter surface can be improved by applying a coating (the surface roughness can be reduced).

Note that the coating layer preferably has open pores. It is prevented that the gas generated from the object to be fired is difficult to escape. Although not particularly limited, for the same reason as the surface layer and the back layer described above, the open porosity of the coating layer may be 5% or more and 70% or less, preferably 20% or more, more Preferably it is 30% or more, and particularly preferably 40% or more. The open porosity of the coating layer is preferably 50% or less, more preferably 45% or less, still more preferably 40% or less, and particularly preferably 35% or less.

When providing a coating layer, the thickness of the coating layer may be 500 μm or less. If the coating layer is too thick, the coating layer may be peeled off by repeated firing. Moreover, when the coating layer is too thick, the cost of the setter increases. From the viewpoint of suppression of peeling and cost increase, the thickness of the coating layer may be 500 μm or less, 400 μm or less, 300 μm or less, 250 μm or less, or 200 μm or less. It may be 150 μm or less, may be 100 μm or less, and may be 50 μm or less.

Further, when providing the coating layer, the thickness of the coating layer may be 5 μm or more from the viewpoint of effectively preventing a chemical reaction between the object to be fired and the setter. The thickness of the coating layer is preferably 10 μm or more, more preferably 20 μm or more, and particularly preferably 50 μm or more from the viewpoint of preventing a chemical reaction between the object to be fired and the setter for a long period of time. is there.

The coating layer can be formed by, for example, gas plasma spraying, water plasma spraying, spray coating, casting, or the like. From the viewpoint that a good open porosity can be obtained, the coating layer is preferably formed by spray coating or pouring. Various materials can be selected for the coating layer depending on the material of the setter and the method of forming the coating layer. As an example, the material of the coating layer is mullite, alumina, alumina-zirconia, Y ₂ O ₃ stabilized zirconia, CaO stabilized zirconia, CaO / Y ₂ O ₃ stabilized zirconia, spinel . From the viewpoint of obtaining a good open porosity and suppressing a chemical reaction with the object to be fired, the material of the coating layer is preferably alumina or alumina-zirconia.

As an example of the setter disclosed in this specification, a ceramic setter for firing electronic components can be given. The setter disclosed in this specification can be suitably used for firing an electronic component having a surface in contact with the setter having a size of about 0.1 mm × 0.2 mm. Although not particularly limited, the technique disclosed in this specification can be suitably applied to a ceramic setter having a width of 50 to 500 mm, a length of 50 to 250 mm, and a thickness of 0.5 to 10 mm, for example. .

(First embodiment)
The setter 10 will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the setter 10 includes a surface layer 2, an intermediate layer 4, and a back surface layer 6. The intermediate layer 4 is provided between the front surface layer 2 and the back surface layer 6. The material of the surface layer 2, the intermediate layer 4, and the back layer 6 is cordierite. The surface of the surface layer 2 and the surface (back surface) of the back surface layer 6 are flat. That is, the front surface layer 2 and the back surface layer 6 are flat. Therefore, the setter 10 itself has a flat plate shape.

The intermediate layer 4 has a honeycomb structure and has a lower density than the front surface layer 2 and the back surface layer 6. Although details will be described later, the opening of the intermediate layer 4 extends in a direction orthogonal to the thickness direction (the direction of arrow 20 in FIG. 1). The opening of the intermediate layer 4 extends in the direction of arrow 20 from one end of the setter 10 to the other end. A side wall 8 is provided on the side surface of the setter 10. The side wall 8 is not provided in the direction in which the opening of the intermediate layer 4 extends. That is, the side walls 8 are provided on two surfaces orthogonal to the direction of the arrow 20 among the side surfaces of the setter 10. The side wall 8 extends in the thickness direction of the setter 10 (perpendicular to the front surface layer 2 and the back surface layer 6).

As shown in FIG. 2, the intermediate layer 4 includes a partition wall 14 and a space (opening) 12 surrounded by the partition wall 14. Therefore, the intermediate layer 4 has a lower density than the front surface layer 2 and the back surface layer 6. The thickness t2 of the surface layer 2 is 100 μm, the thickness t4 of the intermediate layer 4 is 800 μm, and the thickness t6 of the back layer 6 is 100 μm. The setter 10 has a thickness t10 of 1 mm.

The truss structure 16 is constituted by the partition wall 14 in the intermediate layer 4. The truss structure 16 is an example of a honeycomb structure. In the setter 10, a single-stage honeycomb cell is provided between the front surface layer 2 and the back surface layer 6. The side length D16 of the opening 12 of the truss structure 16 is 0.92 mm. The partition wall 14 has a thickness t14 of 100 μm. That is, in the setter 10, the thickness t2 of the front surface layer 2, the thickness t6 of the back surface layer 6, and the thickness t14 of the partition wall 14 are equal. The setter 10 has an aperture ratio of 70% and a hydraulic diameter of 0.53 mm. Note that, at the end portion of the intermediate layer 4 (a portion where a part of the opening 12 is defined by the side wall 8), the area of the opening 12 is approximately half of the area of the other opening 12.

The partition wall 14 is continuous with the front surface layer 2, the back surface layer 6 and the side wall 8. In the setter 10, the surface layer 2, the intermediate layer 4, the back surface layer 6, and the side wall 8 are integrally formed of the same material (cordierite). The surface layer 2, the intermediate layer 4, the back layer 6 and the side wall 8 have open pores, and the open porosity is 35%. Further, the thermal expansion coefficient of the setter 10 is 0.9 ppm / ° C. Note that the thermal expansion coefficient of cordierite in a bulk state (state in which the structure does not have orientation) is 2.2 to 2.8 ppm / ° C. Since the setter 10 has a honeycomb structure in which the intermediate layer 4 is formed by extrusion, the coefficient of thermal expansion can be significantly reduced as compared with a solid setter.

As described above, the setter 10 includes the planar surface layer 2 and the back surface layer 6 and the honeycomb-shaped intermediate layer 4 provided between the surface layer 2 and the back surface layer 6. Since the setter 10 has the honeycomb-like intermediate layer 4, the weight can be reduced compared to a solid setter. The setter 10 can reduce the heat capacity, and can follow the change in the furnace temperature well. Moreover, the hydraulic diameter of the opening 12 of the intermediate layer 4 is 0.53 mm, and the gas in the furnace can move well in the intermediate layer 4. The setter 10 is heated from the outside and the inside (in the intermediate layer 4), and can follow the change in the furnace temperature well.

Further, the thickness of the front surface layer 2 and the back surface layer 6 is sufficiently secured (100 μm), and a sufficient strength can be exhibited despite having a honeycomb structure. Typically, when the thickness of the surface layer is increased, the movement of the gas generated from the material to be fired is prevented at the portion where the material to be fired and the surface layer are in contact. However, in the setter 10, the surface layer 2 has open pores, and the open porosity is adjusted to 35%. Therefore, even in the portion where the object to be fired and the setter 10 are in contact, the gas generated from the object to be fired moves reliably to the outside of the object to be fired, and the object to be fired can be fired satisfactorily. Moreover, the gas in the furnace permeates into the surface layer 2 from the outside of the setter 10 and the opening 12 (intermediate layer 4), and the temperature of the surface layer 2 follows the furnace temperature well. Furthermore, since the side wall 8 is orthogonal to the front surface layer 2 and the back surface layer 6, sufficient compressive strength can be secured at the end of the setter 10.

The setter 10 is an example that embodies the technology disclosed in the present specification, and can take various modifications. Hereinafter, some modified examples of the setter 10 will be described.

3 is different from the setter 10 in the thickness t6a of the back surface layer 6a. See FIG. 1 for a rough appearance. About the setter 10a, about the same structure as the setter 10, the description is abbreviate | omitted by attaching | subjecting the same reference number as the setter 10. FIG.

In the setter 10a, the thickness t6a of the back surface layer 6a is 300 μm. The setter 10 a can be stronger than the setter 10. In the setter 10, the strength can be increased even if the thickness of the surface layer 2 or the intermediate layer 4 is increased in addition to the back surface layer 6. Alternatively, the strength can be increased by increasing the thickness of the surface layer 2 or the intermediate layer 4 without increasing the thickness of the back surface layer 6. However, increasing the thickness of each layer 2, 4 and 6 increases the weight of the setter. The setter 10a can increase the strength while suppressing an increase in weight by increasing only the thickness of the back surface layer that contributes most to the improvement in strength.

The structure of the setter 10a is the same as that of the setter 10 in the structure of the surface layer 2 and the partition wall 14 in contact with the object to be fired. In the setter 10 a, the heat capacity of the surface layer 2 and the intermediate layer 4 in the vicinity of the surface layer 2 does not increase with respect to the setter 10. Therefore, the setter 10a can reduce the heat capacity in the same manner as the setter 10 while improving the strength.

4 is different from the setter 10 in the thickness t14a of the partition wall 14a. See FIG. 1 for a rough appearance. About the setter 10b, about the same structure as the setter 10, the description is abbreviate | omitted by attaching | subjecting the same reference number as the setter 10. FIG.

In the setter 10b, the thickness t14a of the partition wall 14a is 60 μm. The setter 10b can be lighter than the setter 10. Further, by making the partition wall 14 thinner than the setter 10, the opening ratio of the intermediate layer 4 increases (the density of the intermediate layer 4 decreases), and the heat capacity is further reduced. As described above, the back layer contributes most to the strength of the setter. Therefore, even if the thickness of the partition wall is reduced, it does not greatly contribute to the strength reduction of the setter. The setter 10b is lightweight while suppressing a decrease in strength, and can reduce the heat capacity.

In the setter 10b, the thickness of the back surface layer 6 may be the same as that of the setter 10a (FIG. 2). In other words, in the setter 10, the thickness of the back surface layer 6 may be made thicker than that of the surface layer 2, and the thickness of the partition wall 14 may be made thinner than that of the surface layer 2.

5 is different from the setter 10 in the shape of the side wall 8a. See FIG. 1 for a rough appearance. About the setter 10c, about the same structure as the setter 10, the description is abbreviate | omitted by attaching | subjecting the same reference number as the setter 10. FIG. In the setter 10c, the side wall 8a is inclined with respect to the thickness direction. Specifically, the size of the opening 12 is equal at the center portion and the end portion of the intermediate layer 4. As a result, the furnace gas can pass through the entire intermediate layer 4 evenly. The setter 10c can suppress the occurrence of temperature unevenness in the surface.

The feature that the side wall is inclined so that the size of the opening 12 is equal at the center and the end of the intermediate layer 4 can also be applied to the setters 10a and 10b described above.

6 is different from the setter 10 in the structure of the intermediate layer 4. About the setter 10d, about the same structure as the setter 10, the description is abbreviate | omitted by attaching | subjecting the same reference number as the setter 10. FIG. In the setter 10d, the intermediate layer 4 includes truss structures (honeycomb cells) 16a and 16b having two stages. That is, the opening 12 appears twice in the direction connecting the front surface layer 2 and the back surface layer 6 (thickness direction). The side wall 8 extends in the thickness direction of the setter 10d (perpendicular to the front surface layer 2 and the back surface layer 6).

The setter 10d can increase the thickness of the setter without increasing the size of each truss structure. If the size of the truss structure increases too much, the strength of the setter may decrease. By setting it as the truss structure of 2 steps | paragraphs, the thickness of a setter can be ensured, suppressing a strength fall. Or the setter 10d can also be expressed as ensuring the thickness of the setter without increasing the thickness of the front surface layer 2 and the back surface layer 6. That is, the setter 10d can secure a thickness while suppressing an increase in weight.

6 shows the setter 10d having the two- stage truss structures 16a and 16b, the number of stages of the truss structure may be two or more. The number of stages of the truss structure may be 2 or more and 6 or less. Further, in the setter 10d, the thickness of the back surface layer 6 may be made larger than the thickness of the surface layer 2, and / or the thickness of the partition wall 14 may be made thinner than the surface layer 2.

7 can be said to be a modification of the setter 10d. About the setter 10e, about the same structure as the setter 10d, description is abbreviate | omitted by attaching | subjecting the same reference number as the setter 10d. The setter 10e is different from the setter 10d in the structure of the side wall 8b. The outer surface of the side wall 8b has a curve. By having the side wall 8b, the end of the setter 10e can be made difficult to chip.

(Second embodiment)
The setter 210 will be described with reference to FIGS. 8 and 9. The setter 210 is a modification of the setter 10, and items that are common to the setter 10 may be denoted by the same reference numerals as the setter 10 and description thereof may be omitted.

The setter 210 is provided with a rib 30 at the end 34 on the surface layer 2 side. In other words, the central portion 32 of the setter 210 is thinner than the end portion 34. The rib 30 extends along the arrow 20 in which the opening 12 extends (parallel to the direction in which the opening 12 extends). The ribs 30 are provided at both ends of the surface layer 2 in a direction orthogonal to the direction in which the opening 12 extends. By providing the ribs 30, a plurality of setters 210 can be stacked and fired when the object to be fired is fired. The object to be fired is disposed in a space formed by the ribs 30 (a space formed between the loaded setters 210 and 210).

As shown in FIG. 9, the end 34 of the setter 210 includes four stages of truss structures 16a, 16b, 16c and 16d. On the other hand, the central portion 32 includes two- stage truss structures 16c and 16d. Thus, by configuring the rib 30 with the truss structure, an increase in the weight of the setter 210 is suppressed. The wall surface 30a connecting the end portion 34 and the central portion 32 is inclined with respect to the thickness direction. The furnace gas can pass through the entire rib 30 evenly.

In addition, the setter 210 prepares the flat plate provided with the four- stage truss structures 16a, 16b, 16c and 16d shown in FIG. 10, and the truss structures 16a and 16b where the central portion 32 is formed along the broken line 36. It can be easily formed by removing. That is, in the setter 210, the central portion 32 and the rib 30 on which the object to be fired is placed have an integral structure.

FIG. 11 shows the setter 210a. The setter 210a is a modification of the setter 210. About the setter 210a, about the same structure as the setter 210, the same reference number as the setter 210 is attached | subjected and description is abbreviate | omitted. The coating layer 40 is provided in the center part 32 of the setter 210a. The coating layer 40 is made of alumina and is formed on the surface of the surface layer 2 by spray coating. The coating layer 40 has an open porosity of 30% and a thickness of 50 μm.

In addition, you may provide the coating layer 40a in the center part 32 and the wall surface 30a of the setter 210b like the setter 210b shown in FIG. The coating layer 40 may be provided on the surface layer of a flat setter. That is, the coating layer 40 may be provided on the surface of the surface layer 2 of the setters 10, 10a, 10b, 10c, 10d and 10e.

(Third embodiment)
The setter 310 will be described with reference to FIG. The setter 310 is a modification of the setters 10 and 210, and the same reference numerals as those of the setters 10 and 210 may be used for the items common to the setters 10 and 210, and the description thereof may be omitted.

The setter 310 is provided with ribs 330 a at both ends of the surface layer 2 in the direction orthogonal to the direction in which the opening 12 extends (the direction of the arrow 20), like the setter 210. Further, the setter 310 is provided with a rib 330b at one end in the direction in which the opening 12 extends. The rib 330a and the rib 330b are integrated. Therefore, it can be said that the setter 310 has the ribs 330 ( ribs 330 a and 330 b) provided on three sides of the end portion of the surface layer 2. Compared with the setter 210, the setter 310 is in contact with the setters 310 and 310 in three directions when the plurality of setters 310 are stacked. Therefore, the setters 310 and 310 can be loaded stably. Moreover, it can suppress that the surface of the setter 310 falls that to-be-fired material falls.

In the setter 310, a coating layer may be provided on the surface layer 2 and / or the wall surface of the rib 330 (see also FIGS. 11 and 12). When the coating layer is provided on the rib 330, the coating layer may be provided on the wall surface of the rib 330a and the coating layer may not be provided on the wall surface of the rib 330b. Or you may provide a coating layer in both the wall surface of the rib 330a, and the wall surface of the rib 330b. When a coating layer is provided on the wall surface of the rib 330b, the coating layer is provided on the end face of the partition wall 14 while ensuring the opening 12. By doing so, the gas in the furnace passes through the openings 14 of the ribs 330b while preventing the reaction between the object to be fired and the setter surface, so that the temperature of the surface layer 2 can follow the inner atmosphere well.

(Fourth embodiment)
The setter 410 will be described with reference to FIG. The setter 410 is a modification of the setters 10, 210, and 310, and items that are common to the setters 10, 210, and 310 may be omitted by giving the same reference numerals as the setters 10, 210, and 310. .

In the setter 410, the rib 430 surrounds the entire periphery of the end portion of the surface layer 2. In other words, the center part 32 of the setter 410 is recessed. Specifically, ribs 430a are provided at both ends of the surface layer 2 in a direction orthogonal to the direction in which the opening 12 extends (the direction of the arrow 20). In addition, ribs 430b are provided at both ends in the direction in which the opening 12 extends. The rib 430a and the rib 430b are integral. Also in the setter 410, a coating layer may be provided on the surface layer 2 and / or the wall surface of the rib 430. When the coating layer is provided on the rib 430, the coating layer may be provided only on the wall surface of the rib 430a, and the coating layer may not be provided on the wall surface of the rib 430b. Or you may provide a coating layer in both the wall surface of the rib 430a, and the wall surface of the rib 430b. When providing a coating layer on the wall surface of the rib 430b, the coating layer is provided on the end face of the partition wall 14 while ensuring the opening 12. By doing so, while the furnace gas passes through the openings 14 of the ribs 430b while preventing the reaction between the object to be fired and the setter surface, the temperature of the surface layer 2 can follow the furnace atmosphere well.

(5th Example)
The setter 510 will be described with reference to FIGS. 15 and 16. FIG. 15 shows a part of a cross section of the setter 310 and corresponds to the portion shown in FIG. FIG. 16 shows a view of the setter 310 observed from the surface layer 2 side, and the shape of the intermediate layer is indicated by a broken line.

In the setter 510, the opening 12 of the intermediate layer 4 (truss structure) extends in the direction connecting the surface layer 2 and the back surface layer 6 (in the direction of arrow 50). That is, in the setter 510, the partition wall 14 extends in parallel with the arrow 50 direction. Therefore, the setter 510 can increase the compressive strength in the thickness direction. Further, when the opening 12 extends in the direction of the arrow 20 as in the case of the setters 10, 210, etc. (see FIGS. 1 and 8), in order to ensure a large hydraulic diameter, the thickness of the intermediate layer 4 is increased. It is necessary. However, in the case of the setter 510, the hydraulic diameter of the opening 12 can be increased while reducing the thickness of the intermediate layer 4 (that is, reducing the thickness of the setter 510).

The setter 510 can be manufactured by forming the front surface layer 2, the intermediate layer 4 and the back surface layer 6 separately, bonding the layers 2, 4 and 6 with a ceramic paste and firing them at a predetermined temperature. Specifically, the intermediate layer 4 having a honeycomb structure and having openings 12 on the front and back surfaces is formed by, for example, extrusion molding. In addition to the intermediate layer 4, the sheet-like surface layer 2 and the back surface layer 6 are formed by, for example, extrusion molding. Thereafter, the setter 510 can be formed by bonding the front surface layer 2 and the back surface layer 6 to the intermediate layer 4 and baking. By forming the surface layer 2, the intermediate layer 4, and the back layer 6 separately, the materials and / or open porosity of the layers 2, 4, and 6 can be made different. For example, the open porosity of the partition wall 14 of the intermediate layer 4 can be made smaller than the open porosity of the surface layer 2. The strength of the intermediate layer 4 can be further improved while ensuring the open porosity of the surface layer 2. Also in the setter 510, a coating layer may be provided on the surface of the surface layer 2.

(Examination of coating layer thickness)
A coating layer was formed on the surface of the setter 10 (see FIG. 1), and a heat test of the setter 10 itself and a reactivity test with the object to be fired were performed. Note that cordierite was used as the material for the setter 10. As a coating material, a mixture obtained by adding 0.5 part of a hydrophilic organic binder to 100 parts of granular ceramics having an average particle size of 20-100 μm and further adding 60 parts of ion exchange water is introduced into a container containing ceramic cobblestones. Then, the mixture was pulverized and mixed using a pot mill to prepare a slurry. In addition, ion-exchange water is for adjusting the viscosity which is easy to apply the coating material (slurry). Further, for example, alumina cobblestone can be used as the ceramic cobblestone. A trommel can be used in place of the pot mill. A coating material (raw material slurry) produced using a spray gun was applied to the surface of the setter 10 to form a coating layer. The coating time was adjusted, and a 5-600 μm coating layer was formed on the surface of the setter 10 (Sample 1-12). Further, granular ceramics having an average particle size of 20-100 μm were sprayed on the surface of the setter 10 using a plasma spraying machine, and a coating layer of 100 μm was formed on the surface of the setter 10 (Sample 13). Further, the coating material (raw material slurry) was poured onto the surface of the setter 10 to form a 100 μm coating layer on the surface of the setter 10 (Sample 14). As the above-mentioned granular ceramics, for example, zirconia, mullite, alumina or the like can be used. In addition, the setter 10 in which the coating layer was not provided was also subjected to a heating test and a reactivity test (Sample 15). The test conditions and results are shown in FIG.

The heating test was performed in a nitrogen atmosphere under atmospheric pressure without placing the member to be heated on the setter 10 (about the setter 10 itself). In the heating test, the cycle was heated to 1350 ° C. at a rate of temperature increase of 100 ° C./hr, held at 1350 ° C. for 2 hours, and then naturally cooled to room temperature, and then 5 cycles were performed. In FIG. 17, “A” was observed in the sample in which no abnormality was observed in the coating layer after each cycle, and “B” was observed in the sample in which alteration (such as blistering) was confirmed although no peeling occurred. “C” is attached to the sample.

In the reactivity test, 100 heated members (ceramic capacitors) were placed on the setter 10 under atmospheric pressure and in a nitrogen atmosphere, heated to 1200 ° C. at a heating rate of 100 ° C./hr, and then at 1200 ° C. for 10 minutes. The cycle of holding and then naturally cooling to room temperature was taken as 1 cycle, and 5 cycles were performed. FIG. 17 shows that after each cycle, the heated member with uneven firing was “A” on 0-2 samples, and the heated member with uneven firing was “B” on 3-4 samples. A member to be heated is marked with “C” on five or more samples.

As shown in FIG. 17, in the heating test, it was confirmed that when the thickness of the coating layer was 500 μm or less, abnormality (peeling, blistering) of the coating layer could be suppressed. However, when the thickness of the coating layer exceeded 250 μm, a sample in which an abnormality occurred in the coating layer was confirmed as the number of heating test cycles increased. However, when the thickness of the coating layer is 250 μm or less, it was confirmed that no abnormality occurred in the coating layer even when the repeated heating test was performed. Further, in the reactivity test, it was confirmed that the occurrence of uneven firing due to the reaction between the setter and the non-heated member was improved by providing the coating layer (Samples 1 and 15). In particular, if the thickness of the coating layer was 20 μm or more, it was confirmed that even if the number of cycles was increased, no uneven burning occurred in the heated member (all evaluated as “A”). In this test, even if the reactivity test was performed for 5 cycles, a sample having an evaluation of “C” was not confirmed. From the above results, it is preferable to adjust the thickness of the coating layer to 5 to 500 μm, and in particular, by adjusting the thickness to 20 to 250 μm, it is possible to prevent the coating layer from becoming abnormal, and to apply heat to the member to be heated. It was confirmed that firing unevenness can be prevented. In addition, in this test, the difference by the formation method of a coating layer was not confirmed (samples 5, 13, and 14).

In the above embodiment, a setter having a truss shape (triangular shape) as a honeycomb structure has been described. However, the shape of the honeycomb structure may be a quadrangle (square, rectangle), a hexagon, or the like.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

Claims (11)

1. Ceramic setter for firing,
   It has a surface layer, an intermediate layer, and a back layer,
   The intermediate layer has a honeycomb structure and has a lower density than the front surface layer and the back surface layer,
   The surface layer has a flat plate shape, has a thickness of 50 μm or more and 2000 μm or less, and an open porosity of 5% or more and 50% or less.
2. The setter for firing according to claim 1, wherein the back surface layer is flat and has a thickness of 100 µm or more and 2000 µm or less.
3. The firing setter according to claim 1 or 2, wherein the partition wall defining the opening of the honeycomb structure of the intermediate layer has a thickness of 50 µm or more and 2000 µm or less.
4. The firing setter according to claim 3, wherein the hydraulic diameter of the opening is 0.3 mm or more and 7 mm or less.
5. The firing setter according to claim 3 or 4, wherein the opening ratio of the opening is 50% or more and 95% or less.
6. The firing setter according to any one of claims 1 to 5, wherein the opening is opened in a second direction orthogonal to the first direction connecting the front surface layer and the back surface layer.
7. The setter for firing according to any one of claims 1 to 6, wherein the strength of the back surface layer is higher than that of the front surface layer and the intermediate layer.
8. The setter for firing according to any one of claims 1 to 7, wherein a thermal expansion coefficient is 2.0 ppm / ° C or less.
9. The partition of the surface layer and the intermediate layer is continuous,
   The partition walls of the back layer and the intermediate layer are continuous.
   The setter for firing according to any one of claims 1 to 8, wherein the surface layer, the intermediate layer, and the back layer are integrated.
10. The setter for firing according to any one of claims 1 to 9, wherein a coating layer is provided on the surface layer.
11. The firing setter according to claim 10, wherein the coating layer has a thickness of 5 μm or more and 500 μm or less.
    

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