JP2001130981A - Ceramic foam, method for producing the same and heat- resistant frame mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a ceramic foam producible in high production efficiency and at a low cost and to provide a method for producing the ceramic foam. SOLUTION: This ceramic foam 100 is obtained by integrally molding a surface layer 11 made by sintering a surface layer raw material and a substrate 12 prepared by melting and foaming a substrate raw material. Since the surface layer raw material is not melted during baking of the surface layer 11, the baked surface layer 11 is not adhered to a frame mold. Consequently the baked ceramic foam 100 can readily be released from the frame mold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a ceramic foam, a method for producing the same, and a heat-resistant mold.

[0002]

2. Description of the Related Art A ceramic foam is obtained by heating a ceramic material such as SiO ₂ containing a foaming agent such as CaCO ₃ at a high temperature to melt and foam the material.

[0003] For the production of ceramic foam, a mold made of metal or a refractory material such as mullite or cordierite is used. The raw material of the ceramic foam is filled in the mold and heated for a predetermined time in a high-temperature kiln to fire the ceramic foam.

In the production of the above-mentioned ceramic foam, since the raw material is melted in the mold, the fired ceramic foam is deposited in the mold. Therefore, the releasability between the fired ceramic foam and the mold is poor. In particular, in a mold made of a refractory material, the composition of the material forming the mold and the composition of the raw material of the ceramic foam are similar, so that the ceramic foam is easily welded into the mold. When the ceramic foam is fired in a short time using a mold made of a refractory, distortion occurs between the welded ceramic foam and the mold, so that the mold is easily broken.

[0005] The mold to which the ceramic foam is welded cannot be reused. For this reason, the formwork has a short service life and a short life. In addition, since the surface of the ceramic foam welded in the mold is roughened at the time of mold release, it is necessary to perform surface finishing in a separate step.

In general, the load on the mold is reduced by lowering the firing temperature to 1100 ° C. or less. However, when the firing temperature is low, the strength of the fired ceramic foam decreases.

Conventionally, in order to weld such a ceramic foam into the mold, the surface of the metal mold is extremely smoothly polished (mirror polished) so that the ceramic foam remains in the mold. A method of preventing welding is used.

In the method disclosed in Japanese Patent No. 1567328, a sheet material such as glass cloth or ceramics paper is placed on the inner surface of a mold made of a refractory or metal, or alumina powder is placed.
Prevents direct contact between the raw material of the ceramic foam and the mold. This makes it possible to prevent the fired ceramic foam from being welded into the mold.

[0009]

SUMMARY OF THE INVENTION However, 100
When the mold is heated at a high temperature of 0 ° C. or more, oxidation, vitrification and the like occur on the inner surface of the mold. For this reason, even if it is a mirror-polished mold, the inner surface of the mold after use will not be smooth, and the ceramic foam will be easily welded when next used. Therefore, it is necessary to mirror-polish the inside of the mold again after use, which is troublesome and costly.

On the other hand, when a sheet or alumina powder is disposed between the mold and the raw material of the ceramic foam, the cost of the sheet or alumina powder as a consumable becomes large. Further, after the fired ceramic foam is released from the mold, it is necessary to remove the sheet-like material or the alumina powder from the ceramic foam, which is troublesome and costly.

In the case where the above-mentioned sheet-like material or alumina powder is used and the case where a mirror-polished mold is used, a desired pattern is transferred to a ceramic foam at the same time as firing by an uneven pattern formed on the inner surface of the mold. It is difficult. Therefore, after firing the ceramic foam, the pattern processing needs to be performed in another step.

In addition, since the surface of the ceramic foam has irregularities with pores having an average pore diameter of about 1 mm, it is difficult to fuse and pattern the glaze at the same time as firing. There is a need to do.

Further, a metal mold has a higher coefficient of thermal expansion than a ceramic foam, and a large expansion and contraction accompanying heating and cooling during the production of the ceramic foam. Since the fired ceramic foam may be cracked due to such thermal expansion and contraction of the mold, it is difficult to use a metal having a large coefficient of thermal expansion as the material of the mold.

The reduction in manufacturing efficiency and the increase in manufacturing cost due to the complicated manufacturing steps as described above are obstacles to mass production of ceramic foams.

An object of the present invention is to provide a ceramic foam having a high production efficiency and which can be produced at low cost, and a method for producing the same.

Another object of the present invention is to provide a heat-resistant mold that can efficiently produce a ceramic foam at low cost.

[0017]

Means for Solving the Problems and Effects of the Invention In a ceramic foam according to the present invention, a surface layer made of a sintered material is formed on the surface of a base material made of a foam, and the base material and the surface layer are welded to each other. It was done.

In the production of the ceramic foam according to the present invention, the surface layer raw material is filled on the inner surface of the heat-resistant mold, and the base material is filled thereon, and the surface layer raw material and the base material are fired. I do. Thereby, the surface layer raw material is sintered to form the surface layer, and the base material is melted and foamed to form the base material. In addition, the formed surface layer and the base material are welded.

In the ceramic foam according to the present invention, the surface layer raw material in contact with the mold is sintered without melting, so that the formed surface layer and the mold are not welded to each other.
Therefore, the fired ceramic foam can be easily released from the mold, and consumable materials such as glass cloth are provided between the mold and the ceramic foam in order to improve the releasability as in the conventional case. It is not necessary to intervene, or to mirror-finish the inner surface of the mold. Therefore, it is possible to reduce the cost required for the consumable material or the mirror polishing, and it is possible to omit the additional work required for these.

Further, since surface cracks do not occur at the time of mold release, there is no need to perform a surface finishing step of the fired ceramic foam.

Further, the surface of the surface layer made of the sintered material is flat and smooth, so that the glaze can be easily fused or patterned.

From the above points, in the ceramic foam according to the present invention, the manufacturing cost and the number of manufacturing steps can be reduced, so that the productivity of the ceramic foam is improved.

Further, the surface layer made of a sintered material is compressed,
Has great strength against bending and impact. Further, the base material made of a foamed material has a high porosity and a low specific gravity, and has excellent heat resistance and fire resistance. Therefore, a ceramic foam formed by integrally molding such a surface layer and a base material has excellent heat insulating properties and fire resistance, and also has excellent strength.

The material forming the surface layer preferably contains at least one of the materials forming the base material. When the composition of the surface layer raw material and the composition of the base material are similar, the baked surface layer and the base material are welded and strongly bonded. Therefore, in the fired ceramic foam, there is no possibility that the surface layer and the base material are separated.

A glaze may be fused to the surface of the surface layer.
Further, a predetermined uneven pattern may be provided on the surface of the surface layer. Thereby, ceramic foams having various external shapes are obtained. Such a ceramic foam may be formed, for example, by using a mold on which a transfer paper coated with glaze is adhered to the bottom surface, or by using a mold having a predetermined uneven pattern on the bottom surface. It is formed by firing. Therefore, a highly productive ceramic foam is realized.

In the method for producing a ceramic foam according to the present invention, the surface layer raw material is filled in layers on the inner surface of the heat-resistant mold, and the base material is filled on the layered surface layer raw material. The surface material is sintered by firing the material material to form a surface layer, and the base material is formed by melting and foaming the material on the surface layer.

In the method for producing a ceramic foam according to the present invention, since the surface layer is formed between the base material and the mold, it is possible to prevent the base material from being welded to the mold. In addition, since the surface layer raw material is sintered without melting to form the surface layer, the surface layer does not adhere to the mold. Therefore, the fired ceramic foam can be easily released from the mold, and consumable materials such as glass cloth are placed between the ceramic foam and the mold in order to improve the releasability as in the conventional case. It is not necessary to intervene, or to mirror-finish the inner surface of the mold. Therefore, it is possible to reduce the cost required for such consumables and mirror polishing, and it is possible to omit incidental work required for these.

In addition, since the surface break does not occur in the ceramic foam at the time of release from the mold, it is not necessary to perform the surface finishing step of the ceramic foam.

Further, since the surface layer formed by sintering the surface layer raw material is flat and smooth, it is possible to easily fuse and pattern the glaze.

In view of the above, in the method for manufacturing a ceramic foam according to the present invention, the manufacturing cost and the number of manufacturing steps can be reduced, so that the productivity of the ceramic foam is improved.

Further, since the ceramic foam can be prevented from being welded to the mold, the ceramic foam can be fired at a temperature higher than the firing temperature in the conventional manufacturing method. Thereby, it is possible to form a ceramic foam having higher strength.

Preferably, the melting point of the surface layer raw material is higher than the melting point of the base material raw material, and the surface layer raw material and the base material raw material are fired at a temperature between the melting points of the surface layer raw material and the base material raw material.

In this case, the surface layer raw material heated at a temperature lower than the melting point is sintered to form a surface layer. On the other hand, the base material heated at a temperature equal to or higher than the melting point melts and foams to form a base material.

The material constituting the surface layer preferably contains at least one of the materials constituting the substrate.

In this case, since the composition of the surface layer raw material and the composition of the base material are similar, the fired surface layer and the base material are welded and strongly bonded. Therefore, in the fired ceramic foam, there is no possibility that the surface layer and the base material are separated.

A glaze may be applied to the inner surface of the heat-resistant mold. Further, a mold having a predetermined uneven pattern formed on the inner surface may be used as the heat-resistant mold. This makes it possible to form a ceramic foam having a glaze fused to the surface layer or a ceramic foam having a predetermined uneven pattern formed on the surface layer by one firing. This makes it possible to produce ceramic foams having various appearance shapes with high productivity.

The heat-resistant formwork is preferably composed of a side member and a bottom member, and the side member is preferably mounted movably in a horizontal direction with respect to the bottom member.

In this case, the heat-resistant mold expands and contracts with heating during firing and cooling after firing. During firing, the side surface member moves in the horizontal direction with the expansion of the bottom surface member and the base material. The expanded bottom member contracts by cooling after firing. Since the side member is attached to the bottom member so as to be movable in the horizontal direction, when the bottom member contracts, the position of the side member does not change from the position at the time of expansion of the bottom member. Thereby, the load on the ceramic foam due to the contraction of the mold is suppressed, and the fired ceramic foam does not crack. Therefore, it is possible to use a metal having a large coefficient of thermal expansion as a material of the heat-resistant mold.

The heat-resistant formwork according to the present invention comprises a side member and a bottom member, and the side member is attached to the bottom member so as to be movable in the horizontal direction.

When the heat-resistant mold according to the present invention is used, the bottom member and the side member move in the horizontal direction as the raw material expands when the raw material is fired. The expanded bottom member contracts by cooling after firing. Since the side member is attached to the bottom member so as to be movable in the horizontal direction, when the bottom member contracts, the position of the side member does not change from the position at the time of expansion of the bottom member. Thereby, the load on the fired ceramic foam due to the contraction of the mold is suppressed, and the fired ceramic foam does not crack.

By moving the side member relative to the bottom member, the fired ceramic foam can be easily taken out of the mold. Therefore, there is no need to mirror-polish the surfaces of the side and bottom members, and it is not necessary to attach consumables to the side and bottom members. As a result, the manufacturing cost can be reduced and the manufacturing time can be reduced.

[0042]

1 and 2 show an example of a heat-resistant mold used for producing a ceramic foam according to the present invention. FIG. 1 is a plan view of the mold, FIG. 2A is a front view of the mold of FIG. 1, and FIG. 2B is a cross-sectional view of the mold.

As shown in FIGS. 1 and 2 (a) and 2 (b), the mold 50 is composed of four plate-like side members 51 and one plate-like bottom member 52 having a substantially L-shaped cross section. You. Two pin members 60 are attached to the four end surfaces of the bottom member 52, two each in the horizontal direction. FIG.
As shown in (a), a through hole 61 into which the pin member 60 can be inserted is provided at the lower end of each side member 51.
The mold 50 is assembled by inserting the pin member 60 attached to the bottom member 52 into the through hole 61 of each side member 51.

The thickness d ₁ of the side member 51 is, for example, 6 mm, and the thickness d ₂ of the bottom member 52 is, for example, 6 mm.
Vertical length W ₁ and horizontal length W ₂ inside of the mold 50 is 100mm example, the height H is 50mm, for example. As shown in FIG. 2B, each side member 51
It is movable (slidable) in the direction of arrow X in the figure along the pin member 60.

Since the mold 50 is heated at a high temperature,
It is preferable that the metal constituting the mold 50 has high resistance to high temperature and oxidation. For example, in this case, Daido Inconel 601 manufactured by Daido Special Steel Co., Ltd. is used.
The composition of Daido Inconel 601 is as shown in Table 1.

[0046]

[Table 1]

The mold 50 made of the above-mentioned material has a large coefficient of thermal expansion, and expands and contracts greatly with heating during firing and cooling after firing. In this case, at the time of firing, the side member 51 is moved to the pin member 60 as the bottom member 52 expands.
Along the arrow X in the figure. The expanded bottom member 52 contracts by cooling after firing. Here, in the mold 50, since the side member 51 is slidable along the pin member 60, when the bottom member 52 contracts, the position of the side member 51 is set to the position when the bottom member 52 expands. It does not change. Thereby, the load on the ceramic foam due to the contraction of the mold 50 is suppressed, and the fired ceramic foam does not crack. in this way,
In the mold 50 having the above structure, a metal having a large coefficient of thermal expansion can be used as a material.

FIG. 3 is a schematic sectional view showing an example of the ceramic foam according to the present invention. The ceramic foam 100 shown in FIG. 3 has a surface layer 11 having a thickness S _{1 of 1} to 2 mm.
And a base material 12 having a thickness T ₁ of 10 mm.

The surface layer 11 is made of a sintered material. Such a sintered material is a material in which a surface layer raw material 1 described later is heated at a temperature equal to or lower than the melting point and is baked and solidified to form a denser and stronger crystal. The surface layer 11 has high strength against compression, bending and impact. The surface layer 11 formed by sintering is in an unfired state, and has a flat, dense, and smooth surface.

On the other hand, the base material 12 is made of a foamed material obtained by melting and foaming a base material 2 described later. Since such a base material 12 has a high porosity and a low specific gravity, it has excellent heat insulating properties and fire resistance.

The ceramic foam 100 composed of the surface layer 11 and the substrate 12 as described above has excellent heat insulating properties and fire resistance, and also has excellent strength.

In the ceramic foam 100, since the surface of the surface layer 11 is flat and smooth, the glaze can be easily fused and patterned without forming a new flat and smooth surface as a pre-process. It is possible to do.

Hereinafter, a method for manufacturing the ceramic foam 100 will be described. FIG. 4 is a schematic process sectional view showing an example of the method for producing a ceramic foam according to the present invention.

As shown in FIG. 4A, the mold 50 shown in FIGS. 1 and 2 is used when manufacturing the ceramic foam 100.

In the above-described mold 50, the side member 51
Then, the surface layer raw material 1 is filled with the thickness S ₂ so as to cover the surface of the bottom member 52. Further, the substrate material 2 is filled on the surface layer material 1 with a thickness T ₂ . The thickness S ₂ of the surface layer raw material 1 is about 1 to ₂ mm, and the thickness T ₂ of the base material ₂ is 5 mm.
It is about. The compositions of the surface layer raw material 1 and the base material 2 are as shown in Table 2.

[0056]

[Table 2]

In this case, the surface layer raw material 1 and the base material 2
Is in powder form. The particle size distribution of the raw material powder in the surface layer raw material 1 and the base material 2 is as shown in Table 3.

[0058]

[Table 3]

Next, the surface layer raw material 1 filled in the mold 50
The substrate material 2 is fired in a kiln such as a roller hearth furnace at 1050 to 1250 ° C. for 1 hour and 30 minutes under atmospheric pressure. Here, the firing temperature is set to a temperature equal to or higher than the sintering temperature of the surface layer raw material 1 and lower than the melting point and equal to or higher than the melting point of the base material 2. If the firing temperature is lower than 1050 ° C., sufficient fire resistance cannot be obtained in the fired ceramic foam 100. When the temperature is higher than 1250 ° C., deterioration of the mold 50 is accelerated.

As shown in FIG. 4B, the surface layer raw material 1 having a melting point higher than the sintering temperature and containing no CaCO ₃ , which is a main component of the foaming agent, does not melt and foam, but is sintered. The surface layer 11 is formed. Therefore, usually, the volume of the surface layer 11 is slightly reduced as compared with the volume of the surface layer raw material 1. The surface layer 11 thus formed has a flat and smooth surface.

On the other hand, the base material 2 having a melting point lower than the sintering temperature and containing CaCO ₃ as a foaming agent increases in volume by melting and foaming, has an average foaming diameter of about 1 mm, and has a stable foaming state. A substrate 12 having a thickness of about 10 mm is formed.

Here, as shown in Table 2, since the composition of the surface layer raw material 1 and the composition of the base material 2 are similar, the formed surface layer 11 and the base material 12 are welded. In this case, since the composition of the surface layer raw material 1 and the composition of the base material 2 are similar, at the interface between the surface layer raw material 1 and the base material 2, they are both joined in a molten state, so that the welding is performed. It is thought to happen. In this manner, the ceramic foam 100 integrally formed by welding the surface layer 11 and the base material 12 is fired. In the ceramic foam 100, since the surface layer 11 and the base material 12 are integrally formed, there is no possibility that both are separated.

During firing of the ceramic foam 100, the mold 50 thermally expands by heating at a high temperature. In this case, with the thermal expansion of the bottom member 52 of the mold 50 and the base material 2, the side member 51 moves in the direction of arrow X in the drawing. The ceramic foam 100 is fired in the expanded mold 50 in this manner. The thermally expanded mold 50 and the fired ceramic foam 100 shrink with cooling after firing. In this case, the mold 50 made of metal has a larger coefficient of thermal expansion than the ceramic foam 100.
For this reason, the contraction of the mold 50 is caused by the ceramic foam 100
Larger than the shrinkage of Here, in this example,
Since the side member 51 of the mold 50 is slidable along the pin member 60, the position of the side member 51 does not move as it is when the bottom member 52 is expanded, regardless of the contraction of the bottom member 52. A gap is created between the side member 51 and the bottom member 52. Therefore, the load on the ceramic foam 100 due to the contraction of the mold 50 is reduced.

In the present embodiment, since the surface layer 11 is formed between the mold 12 and the base 12 formed by melting and foaming, it is possible to prevent direct contact between the base 12 and the mold 50. It becomes possible. Thereby, the base material 12 can be prevented from being welded to the mold 50. Further, since the surface layer 11 is formed by sintering, the surface layer 11 is not welded to the mold 50.
Therefore, the fired ceramic foam 100 can be easily released from the mold 50. Thereby, the mold 50 can be used repeatedly as it is.

In particular, in this embodiment, the mold 50 can be disassembled by removing the side member 51 from the pin member 60. Thereby, the fired ceramic foam 1
00 can be easily taken out.

As described above, in this embodiment, since the ceramic foam 100 can be easily released from the mold 50, the surface of the mold 50 does not need to be mirror-polished unlike the conventional method for manufacturing a ceramic foam. Also, there is no need to use consumables such as glass cloth as described above. For this reason,
It is possible to reduce costs for mirror polishing and consumables, and to save labor and time required for mirror polishing and labor and time required for removing consumables from the ceramic foam 100.

Since the surface layer 11 is not roughened at the time of release, it is not necessary to perform a surface finishing step.

Further, since the surface of the surface layer 11 is flat and smooth, it is not necessary to newly form a surface as a pre-processing when performing the fusing or patterning of the glaze.

From the above, in this example, the manufacturing cost and the number of manufacturing steps can be reduced.
The productivity of the ceramic foam is improved.

Further, in this embodiment, since the side member 51 of the mold 50 is slidable along the pin member 60, even when the coefficient of thermal expansion of the metal constituting the mold 50 is large, the ceramic foam may be used. There is no crack in 100.

Further, in this example, since the releasability of the ceramic foam 100 from the mold 50 is good, the firing temperature (110) in the conventional method for manufacturing a ceramic foam is used.
Thus, the ceramic foam 100 can be fired at a temperature higher than 0 ° C. or lower. Thereby, a ceramic foam 100 having high strength is obtained.

In this embodiment, the powdery surface layer raw material 1 is solidified into a sheet or clay by adding a binder to the surface layer raw material 1, and the sheet or clay-like surface layer raw material 1 is formed into a mold. 50 may be arranged.

Further, the surface layer raw material 1 may contain a small amount of a foaming agent, for example, CaCO ₃ . In this case, the surface layer raw material 1
And the base material 2 are more similar in composition, so that the surface layer 1
1 and the base material 12 are further increased. In addition, since the surface layer raw material 1 is foamed, the difference in volume change between the surface layer raw material 1 and the base material 2 is reduced, so that distortion and stress in the fired ceramic foam 100 are reduced.

In any of the above cases, the thickness S ₂ of the surface layer raw material 1 to be filled in the mold 50 is 0.5 mm
Above. When the thickness S ₂ of the surface layer raw material 1 is less than 0.5 mm, the base material 2 is mixed into the surface layer raw material 1.
The surface layer 11 in which the foam material is contained in the sintered material is formed.
In such a surface layer 11, since the base material 2 mixed in the surface layer material 1 is melted and welded to the mold 50,
The releasability between the fired ceramic foam 100 and the mold 50 is deteriorated. In the surface layer 11 containing a foam material, the flatness and smoothness of the surface are lost.

In this embodiment, CaCO ₃ is used as a main component of the foaming agent in the base material 2. In addition, Na ₂ CO ₃ , Mg ₂ CO ₃ , K ₂ CO ₃ , SrCO _3
3 or the like may be used.

Sintering temperature of surface layer material 1 and base material 2
Are affected by the composition of the raw materials constituting each. Of the materials constituting the surface layer raw material 1 and the base material 2, Al ₂ O ₃ and K ₂ O have the effect of increasing the sintering temperature and melting point. In addition, SiO ₂ and Na ₂ O
Has the effect of lowering the sintering temperature and melting point. Therefore, depending on the ratio of Al ₂ O ₃ , K ₂ O, SiO ₂ and Na ₂ O, the sintering temperature of the surface layer raw material 1 and the base material 2
Is determined. Here, by determining the composition of either the surface layer raw material 1 or the base material 2,
The other composition is limited. That is, since the sintering temperature of the surface layer raw material 1 is determined by determining the composition of the surface layer raw material 1, the composition of the base material 2 is set so that the melting point of the base material 2 is lower than this sintering temperature. . Also, base material 2
Since the melting point of the base material 2 is determined by determining the composition, the composition of the surface layer raw material 1 is set so that the sintering temperature of the surface layer raw material 1 becomes higher than this melting point.

The particle size (particle size) of the raw material powder in the surface layer raw material 1 and the base material 2 is 0.48 mm or less (particle size 30) or less, particularly 0.058 to 0.22 mm (particle size 80 to 2).
00). If the particle diameter of the raw material powder of the surface layer raw material 1 is too large, the surface of the formed surface layer 11 becomes rough, and the glaze becomes difficult to adhere. On the other hand, if the particle size is too small, cracks are likely to occur in the surface layer 11. Further, since the sintering temperature of the surface layer raw material 1 is affected by the particle diameter of the raw material powder, if the particle diameter of the raw material powder of the surface layer raw material 1 is distributed over a wide range, the sintering temperature of the surface layer raw material 1 is reduced. Setting the sintering temperature becomes difficult, and the sintering state of the formed surface layer 11 becomes unstable.

In this example, the mold 50 is made of Kanthal (Mo).
Si ₂ , MoWSi ₂ ). In addition,
In this example, a case where the inside of the kiln is filled with air is described. Therefore, a metal having high oxidation resistance is used as the metal forming the mold 50. Alternatively, when the mold 50 is filled with an inert gas, oxidation of the mold 50 does not occur. Therefore, a mold 50 made of a metal such as stainless steel, graphite, or tungsten may be used.

Further, the mold 50 may be made of a refractory having a different composition from the surface layer raw material 1 in addition to the metal.
When the mold 50 is made of a refractory having a composition similar to that of the surface layer raw material 1, the formed surface layer 11
Is welded to the mold 50, so that the releasability between the fired ceramic foam 100 and the mold 50 is poor. On the other hand, when the mold 50 is made of a refractory having a composition different from that of the surface layer raw material 1, for example, SiC, ZnO ₂ or the like, the formed surface layer 11 does not adhere to the mold 50, The releasability of the formed ceramic foam 100 and the mold 50 is good.

In this example, the base material 2 and the mold 5
0 does not come into direct contact with the
If the composition of the refractory constituting the mold 50 is
The composition of the raw material 2 may be similar. That is, the surface layer
Raw material 1 is SiO_Two, Al_TwoO _Three, Na_TwoDoes not contain O etc.
Made of a material that can be combined with the base material 2
If the composition of the refractory constituting the mold 50 is
2 and SiO 2_Two, Al_TwoO_Three, Na_TwoO etc.
May be included.

FIG. 5 is a schematic sectional view showing another example of the method for producing a ceramic foam according to the present invention. FIG. 5 illustrates a case where a pattern is transferred to a ceramic foam simultaneously with firing.

The manufacturing method of the ceramic foam shown in FIG. 5 is similar to that of the ceramic foam 1 shown in FIG. 4 except for the following points.
00 is the same as the manufacturing method.

In this example, as shown in FIG. 5A, a mold having the same structure as the mold 50 of FIG. 1 except that a plurality of protrusions 54 are provided on the inner surface of the bottom member 53. 5
5 is used. In such a mold 55, the projection 5
4 form an uneven pattern on the bottom surface. The mold 55 is filled with the surface layer raw material 1 and the base material 2 in this order.

Subsequently, as shown in FIG. 5B, the surface layer raw material 1 and the base material 2 are heated together with the mold 55 at a high temperature. Thereby, the surface layer raw material 1 sinters and the surface layer 11
Is formed, and the groove pattern 20 corresponding to the protrusion 54 is transferred to the surface layer 11. On the other hand, the base material 2 is melted and foamed to form the base material 12. Thus, the ceramic foam 110 is fired. afterwards,
The fired ceramic foam 110 is released from the mold 55.

As described above, as shown in FIG. 6, the surface layer 11 made of the sintered material and the base material 12 made of the foam material are integrally formed and the groove pattern 20 corresponding to the projection 54 of the mold 55 is formed. Is formed on the surface of the surface layer 11 to obtain a ceramic foam 110.

In this example, as in the method for manufacturing a ceramic foam shown in FIG. 4, the surface layer 11 is formed between the mold 12 and the base 12 formed by melting and foaming. And the mold frame 55 can be prevented from directly contacting each other. Thereby, the base material 12 can be prevented from being welded to the mold frame 55. On the other hand, since the surface layer 11 is in direct contact with the mold 55, the uneven pattern formed on the bottom surface of the mold 55 is transferred to the surface layer 11 during firing. Here, since the surface layer 11 is formed by sintering, it is not welded to the mold 55. Accordingly, the fired ceramic foam 110 is easily released from the mold frame 55, and the surface of the surface layer 11 on which the groove pattern 20 is formed does not become rough during the release.

As described above, in this example, since the concave and convex pattern of the mold 55 can be accurately transferred to the surface of the ceramic foam 110 at the same time as firing, the concave and convex pattern of the mold 55 can be used. The pattern can be easily formed on the ceramic foam 110. Thereby, the step of performing pattern processing on the ceramic foam 110 becomes unnecessary, and the productivity of the ceramic foam 110 is further improved.

In the ceramic foam 110, the surface of the surface layer 11 is provided with groove-shaped patterns 2 corresponding to joints.
By forming 0, it is possible to manufacture a ceramic foam 110 having an appearance similar to that of brickwork.

FIG. 7 is a schematic process sectional view showing another example of the method for producing a ceramic foam according to the present invention. FIG. 7 illustrates a case where pattern transfer and glaze fusion are performed on a ceramic foam at the same time as firing.

The method for producing the ceramic foam shown in FIG. 7 is the same as the method for producing the ceramic foam shown in FIG. 5 except for the following points.

As shown in FIG. 7A, the mold 55 shown in FIG.
The glaze 30 is applied between the protrusions 54 on the bottom surface of the mold, that is, in the concave portions of the concave and convex pattern formed on the mold frame 55.

Subsequently, as shown in FIG. 7B, the surface layer raw material 1 and the base material 2 are heated together with the mold 55 at a high temperature. Thereby, the surface layer raw material 1 sinters and the surface layer 11
Are formed, and projections 5 are formed on the formed surface layer 11.
The groove pattern 20 corresponding to No. 4 is transferred, and the glaze 30 is fused to the surface of the surface layer 11 excluding the groove pattern 20. On the other hand, the base material 2 is melted and foamed to
2 are formed. Thus, the ceramic foam 1
20 is fired. After that, the ceramic foam 120 is released from the mold 55.

As described above, the surface layer 11 made of the sintered material and the base material 12 made of the foam material are integrally formed as shown in FIG.
Is provided, and the ceramic foam 120 obtained by fusing the glaze 30 is obtained.

In this example, since the surface layer 11 is formed between the base 12 and the mold 55 formed by melting and foaming, it is possible to prevent direct contact between the base 12 and the mold 55. . Thereby, the base material 12 can be prevented from being welded to the mold frame 55. On the other hand, since the surface layer 11 is in direct contact with the mold 55, the
The concave / convex pattern formed on the bottom surface is transferred and the glaze is fused. In this case, since the surface of the surface layer 11 made of the sintered material is flat and smooth, the glaze is easily fused. Here, since the surface layer 11 is formed by sintering, it is not welded to the mold 55. Therefore, the fired ceramic foam 120 is easily released from the mold frame 55. At the time of release, the surface of the surface layer 11 on which the groove pattern 20 is formed and the glaze 30 is fused is not likely to occur. Absent.

As described above, in this example, the mold 55 is formed on the surface layer 11 of the ceramic foam 120 at the same time as firing.
It is possible to accurately transfer the concave and convex pattern, and to further fuse the glaze. Thereby, the ceramic foam 1
The step of performing pattern processing on 20 becomes unnecessary,
Since the step of applying the glaze and the pre-processing step therefor are not required, the productivity of the ceramic foam 120 is further improved.

In the method for producing a ceramic foam according to the present invention, if desired, the surface of the surface layer 11 of the ceramic foam 120 can be patterned at the same time as firing.

[0097]

Example 1 A ceramic foam 100 shown in FIG. 3 was manufactured by the method for manufacturing a ceramic foam shown in FIG. In this case, the compositions of the surface layer raw material 1 and the base material 2 are as shown in Table 4.

[0098]

[Table 4]

The surface layer raw material 1 and the base material 2 having the above-mentioned compositions had melting points of about 1180 ° C. and about 1130 ° C., respectively.

In Example 1, the firing temperature was 1150
° C. Thereby, the surface layer raw material 1 is sintered to form the surface layer 11, and the base material 2 is melted and foamed to form the base material 1.
2 was formed. The setting of the temperature in the kiln is as shown in FIG.

The ceramic foam 100 manufactured as described above was easily released from the mold 50. No crack or crack was observed at the interface between the surface layer 11 of the ceramic foam 100 and the substrate 12. Further, the flexural strength of the ceramic foam 100 is measured according to JIS R
As a result of measurement in accordance with No.5201, it was 53 kg / cm ² .

For comparison, the bending strength of the surface layer 11 made of a sintered material was measured by the same method as described above and found to be 49 kg / cm ² .

Example 2 The ceramic foam 100 shown in FIG. 3 was manufactured by the method for manufacturing a ceramic foam shown in FIG. The composition of the surface layer raw material 1 and the base material 2 in this case is as shown in Table 5.

[0104]

[Table 5]

The surface layer raw material 1 and the base material 2 having the above compositions had melting points of about 1130 ° C. and about 1050 ° C., respectively.

In Example 2, the firing temperature was set to 1100
° C. Thereby, the surface layer raw material 1 is sintered to form the surface layer 11, and the base material 2 is melted and foamed to form the base material 1.
2 was formed. The setting of the temperature in the kiln is as shown in FIG.

The ceramic foam 100 manufactured as described above was easily released from the mold 50. No crack or crack was observed at the interface between the surface layer 11 of the ceramic foam 100 and the substrate 12. Further, the bending strength of the ceramic foam 100 was measured by the same method as in Example 1, and as a result, it was 38 kg / cm ² .

For comparison, the bending strength of the surface layer 11 made of a sintered material was measured by the same method as described above, and as a result, it was 35 kg / cm ² .

As shown in Examples 1 and 2 above, by forming the surface layer 11 made of a sintered material,
Since the welding of the ceramic foam 100 to the mold 50 can be prevented, the releasability of the ceramic foam 100 and the mold 50 is improved. Further, by integrally molding the surface layer 11 and the base material 12, the strength of the ceramic foam 100 becomes larger than the strength of the surface layer 11. In Example 1, the firing temperature of the ceramic foam 100 was higher than that in Example 2;
In comparison with Example 2, the ceramic foam 100
The strength of is increased.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a heat-resistant mold according to the present invention.

FIG. 2 is a side view and a sectional view of the heat resistant mold shown in FIG.

FIG. 3 is a schematic sectional view showing an example of a ceramic foam according to the present invention.

FIG. 4 is a schematic process sectional view showing an example of the method for producing a ceramic foam according to the present invention.

FIG. 5 is a schematic process sectional view showing another example of the method for producing a ceramic foam according to the present invention.

FIG. 6 is a schematic sectional view showing an example of a ceramic foam produced by the method for producing a ceramic foam shown in FIG.

FIG. 7 is a schematic process sectional view showing another example of the method for producing a ceramic foam according to the present invention.

8 is a schematic cross-sectional view showing one example of a ceramic foam produced by the method for producing a ceramic foam shown in FIG.

FIG. 9 is a diagram showing a temperature change in a kiln in Example 1 and Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Surface layer raw material 2 Base material 11 Surface layer 12 Base material 20 Groove pattern 30 Glaze 50,55 Mold 51 Side member 52,53 Bottom member 54 Projection 60 Pin member 100,110,120 Ceramic foam

Claims (10)

[Claims] 1. A ceramic foam, wherein a surface layer made of a sintered material is formed on a surface of a base material made of a foamed material, and the base material and the surface layer are welded to each other. 2. The ceramic foam according to claim 1, wherein the material forming the surface layer includes at least one of the materials forming the base material. 3. The ceramic foam according to claim 1, wherein a glaze is fused to the surface of the surface layer. 4. The ceramic foam according to claim 1, wherein a predetermined concavo-convex pattern is provided on the surface of the surface layer. 5. Filling the inner surface of the heat-resistant formwork with the surface layer raw material in a layered form, filling the layered surface layer raw material with a base material, and firing the surface layer raw material and the base material. A method for producing a ceramic foam, comprising sintering the surface layer raw material to form a surface layer, and melting and foaming the base material on the surface layer to form a base material. 6. The melting point of the surface layer raw material is higher than the melting point of the base material, and the temperature of the surface layer raw material and the base material is between the melting point of the surface layer raw material and the melting point of the base material. 6. The method for producing a ceramic foam according to claim 5, wherein the firing is performed. 7. The method for producing a ceramic foam according to claim 5, wherein the material forming the surface layer includes at least one of the materials forming the base material. 8. The method for producing a ceramic foam according to claim 5, wherein a mold having a predetermined uneven pattern formed on an inner surface is used as the heat-resistant mold. 9. The heat-resistant formwork includes a side member and a bottom member, and the side member is mounted movably in a horizontal direction with respect to the bottom member. The method for producing a ceramic foam according to any one of the above. 10. A heat-resistant formwork comprising a side member and a bottom member, wherein the side member is mounted movably in a horizontal direction with respect to the bottom member.