KR101401084B1 - Particle-stabilized ceramic foams coated on ceramic materials and the method for manufacturing the same - Google Patents

Abstract

The present invention relates to a ceramic material coated with a colloidal particle-stabilized ceramic foam and a method for manufacturing the ceramic material.
The present invention includes a support formed of a ceramic material and a ceramic foam coating layer coated on one side of the support, wherein the ceramic foam coating layer is formed by a colloid particle stabilization method and has a pore structure of a cell shape.
The method for producing a ceramic material according to the present invention may further comprise: a support forming step of forming a ceramic material support by a method other than sintering or sintering; a material preparing step of preparing a raw powder and a surfactant; A method of manufacturing a ceramic foam, comprising the steps of: preparing a ceramic foam by mixing raw material powder and water to form a mixture, adding a surfactant, and then forming a colloid particle stabilized foam; A ceramic foam coating step of coating a ceramic foam to form a coating layer, a drying step of drying the support and the ceramic foam coating layer, and a sintering step of sintering the dried support and the ceramic foam coating layer. According to the present invention, the ceramic foam coating layer and the support are bonded to each other without a different bonding agent, and the rigidity of the ceramic material is maintained, and the thermal conductivity can be controlled by the ceramic foam.

Description

TECHNICAL FIELD [0001] The present invention relates to a ceramic material coated with a colloidal particle-stabilized ceramic foam and a method for manufacturing the ceramic material.

The present invention relates to a ceramic material coated with a colloidal particle-stabilized ceramic foam and a method for manufacturing the ceramic material.

Foam refers to a substance in which a gas is held in a liquid or solid state. Most of the substance is formed of a gas and the gas is accommodated in a space formed by a liquid or a thin film. I have.

Among the foam of the above-mentioned type, the solid foam may be classified into an open-cell foam and a closed-cell foam. In an example of the open-cell foam, A bath sponge can be mentioned.

One example of the waste foam is an outdoor mat, and the waste foam has a form in which the gas is surrounded by a solid in the separated region.

On the other hand, the ceramic foam is made of a non-polymer ceramic such as a polyurethane foam, a polystyrene foam and the like in the classification of the solid foam.

Generally, a method of manufacturing a ceramic foam is constituted such that a ceramic porous slurry is impregnated with an open pore foam made of a polymer, followed by drying and sintering, thereby pyrolyzing and vaporizing the ceramic polymer, and leaving only the ceramic partition wall structure.

On the other hand, US 2009-00325780 A1, entitled " Ultrastable Particle-Stabilized Foams and Emulsions ", discloses a method of manufacturing a ceramic foam using colloidal particle stabilization.

However, the ceramic foam produced as described above has effects of insulation, soundproofing, absorption of harmful substances, filtration of molten metal, etc., but has a weak strength.

Therefore, in order to utilize the ceramic foam material in various fields, there is a need for a technique of bonding or coating a ceramic foam to a ceramic substrate or a substrate having a relatively high strength.

However, with the conventional impregnation method using a polymer foam, it is difficult to realize a process of bonding or coating a ceramic foam having a desired thickness and shape to a ceramic support or a substrate, and a third joint When a material is applied, there arises a problem of degradation of properties including strength.

It is an object of the present invention to provide a ceramic foam and a ceramic support manufactured by a colloid particle stabilization method which are directly bonded to each other through solid phase diffusion to thereby form a colloid particle stabilized ceramic foam capable of simultaneously including characteristics inherent to the ceramic foam and characteristics inherent to the ceramic support To provide a ceramic material.

Another object of the present invention is to provide a method of manufacturing a ceramic material coated with a colloidal particle-stabilized ceramic foam capable of simultaneously including the characteristics of the ceramic foam and the characteristics of the ceramic support.

The present invention includes a support formed of a ceramic material and a ceramic foam coating layer coated on one side of the support, wherein the ceramic foam coating layer is formed by a colloid particle stabilization method and has a pore structure of a cellular shape.

The ceramic foam coating layer is formed by any one of spin coating, pressure casting, slip casting, and dip-coating.

The ceramic foam coating layer has a thickness of 0.1 to 50 mm.

And the support is formed by sintering.

The support and the ceramic foam coating layer are directly connected to each other by diffusion bonding through solid-state diffusion.

And the ceramic foam coating layer has a porosity of 80 to 95%.

The support and the ceramic foam coating layer is aluminum nitride (AlN), silicon nitride (Si ₃ N _4), silicon carbide (SiC), zirconium carbide (ZrC), tungsten carbide (WC), alumina (Al ₂ O _3), cordierite And is formed using a single powder of one of cordierite, mullite, and zirconia (ZrO ₂ ) or one or more composite powders.

The method of manufacturing a ceramic material according to the present invention includes a support forming step of forming a ceramic material support by a method other than sintering or sintering, a material preparing step of preparing a raw powder having the same composition as the support and a surfactant, A step of preparing a colloidal particle-stabilized foam by mixing a raw material powder prepared in the material preparation step with water to form a mixture, adding a surfactant, and a step of forming a ceramic foam on one surface of the support, A ceramic foam coating step of coating the ceramic foam prepared in the foam manufacturing step to form a coating layer, a drying step of drying the support and the ceramic foam coating layer, and a sintering step of sintering the dried support and the ceramic foam coating layer, In the support forming step, aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ) Chemistry silicon (SiC), zirconium carbide (ZrC), tungsten carbide (WC), alumina (Al ₂ O _3), cordierite (Cordierite), any one of a single powder or of mullite (Mullite), zirconia (ZrO ₂₎ Characterized in that the support is formed using one or more composite powders.

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According to the present invention, it is possible to form a ceramic foam coating layer on a ceramic substrate without using different kinds of adhesive materials. Therefore, the produced ceramic material is advantageous in that it can maintain the basic strength of the ceramic foam coating layer while exhibiting functions such as heat insulation, soundproofing, absorption of harmful substances, filtration of molten metal, and the like.

Further, since the shape of the ceramic foam to be bonded to the support of the ceramic material can be freely controlled by controlling the number of coatings and the thickness, the convenience of the process is improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing the structure of a ceramic material according to the present invention. FIG.
2 is a flow chart showing a process of manufacturing a ceramic material according to the present invention.
3 is a Scanning Electron Microscope (SEM) photograph of a ceramic foam to form a ceramic coating layer, which is a main component of the ceramic material according to the present invention.
4 is a scanning electron microscope (SEM) photograph showing an embodiment of the ceramic material according to the present invention.
5 is a scanning electron microscope (SEM) photograph showing an enlarged view of a bonding portion between a ceramic substrate and a ceramic coating layer according to the present invention.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. It is to be understood, however, that the spirit of the invention is not limited to the embodiments shown and that those skilled in the art, upon reading and understanding the spirit of the invention, may easily suggest other embodiments within the scope of the same concept.

FIG. 1 is a schematic view showing a structure of a ceramic material according to the present invention.

As shown in the figure, the ceramic material 100 according to the present invention is formed by bonding a ceramic foam coating layer 120 formed by coating a colloid particle-stabilized ceramic foam on one side of a support 140 formed of a ceramic material.

In detail, the support 140 is an aluminum nitride (AlN), silicon nitride (Si ₃ N _4), silicon carbide (SiC), zirconium carbide (ZrC), tungsten carbide (WC), alumina (Al ₂ O _3), cordierite A single powder of cordierite, mullite or zirconia (ZrO ₂ ), or at least one composite powder is formed by a method other than sintering or sintering.

The ceramic foam coating layer 120 is formed by forming a ceramic foam by a colloid particle stabilization method using powders having the same composition as the support 140 and coating the formed ceramic foam on one surface of the support 140.

In addition, the ceramic foam coating layer 120 may include micropores 122 of various sizes by selectively adding a surfactant.

The ceramic foam coating layer 120 may be formed on one surface of the support 140 by spin coating or dip coating and may be formed to have a thickness of 0.1 to 50 mm. do.

In particular, when the thickness of the ceramic foam coating layer 120 is less than 0.1 mm, the supporting function can not be performed smoothly. When the thickness of the ceramic foam coating layer 120 is 50 mm or more, The bonding strength is lowered and the possibility of breakage increases.

Meanwhile, the ceramic foam coating layer 120 is coated on the support 140 without a different kind of bonding material, and is then bonded through a sintering process.

That is, the ceramic foam coating layer 120 and the support 140 are formed of powders having the same composition and are directly connected to each other by diffusion bonding through solid-state diffusion while being sintered.

Therefore, according to the present invention, the ceramic foam can be coated on the ceramic substrate, which is difficult to realize in the conventional polymer foam impregnation method.

Hereinafter, a process for manufacturing the ceramic material 100 will be described.

FIG. 2 is a flowchart illustrating a manufacturing process of a ceramic material according to the present invention.

As shown in the figure, the method of manufacturing a ceramic material according to the present invention includes a support forming step S100 for forming a ceramic support 140, a preparing step S200 for preparing a ceramic foam to be coated on the support 140, (S300) for preparing a ceramic foam using the prepared material, a ceramic foam coating step (S400) for coating the prepared ceramic foam on the support (140), and the ceramic foam coating step (S400) A drying step S500 of drying the formed ceramic foam coating layer 120 and the support 140 and a sintering step S600 of sintering the dried ceramic foam coating layer 120 and the support 140 together.

In detail, the supporting member forming step (S100) of aluminum nitride (AlN), silicon nitride (Si ₃ N _4), silicon carbide (SiC), zirconium carbide (ZrC), tungsten carbide (WC), alumina (Al ₂ O _3), A single powder or at least one composite powder of cordierite, mullite, and zirconia (ZrO ₂ ) is formed to have a certain shape by a method other than sintering or sintering.

In the material preparing step S200, a powder having the same composition as that of the support 140 and a surfactant are prepared. Various surfactants including valeric acid may be used as the surfactant.

On the other hand, when the material preparation step S200 is completed, the ceramic foam manufacturing step S300 for forming the ceramic foam using the prepared material is performed.

In the step of manufacturing the ceramic foam (S300), air is injected into the mixture prepared by mixing the prepared ceramic powder and the surfactant by wet mixing to form a foam-like foam.

In the ceramic foam coating step S400, the foam-like foam prepared as described above is spin-coated, pressure-casted, slip casted, dip-coated, The support 140 may be coated on one surface thereof.

Also, in the ceramic foam coating step (S400), the thickness of the ceramic foam coating layer 120 can be controlled by the number of times and time of coating.

On the other hand, after the ceramic foam coating step (S400) is performed, a drying step (S500) for drying the coated ceramic foam is performed.

In the drying step (S500), the support 140 coated with the ceramic foam coating layer 120 is heated to prepare for sintering.

When the drying step (S500) is completed, the above-described sintering step (S600) is performed.

In the sintering step S600, the ceramic foam coating layer 120 coated on the upper surface of the support body 140 is heated and fired so that the ceramic foam coating layer 120 and the support body 140 can be diffusion-bonded.

After the firing step (S600), a final polishing step may be further performed to adjust the thickness of the adsorption layer or increase the precision of the surface.

Hereinafter, an embodiment of a ceramic material coated with a colloidal particle-stabilized ceramic foam according to the present invention and a ceramic material manufactured using the method will be described.

Alumina (Al ₂ O ₃ ) was used as a raw material powder for producing the ceramic support 140 and the ceramic foam coating layer 120, and Valeric Acid was used as a surfactant.

The measured raw material powder and surfactant were mixed by wetting and distilled water was used as a solvent.

Volume ratio of powder and balls was 1: 2 in raw material mixing and distilled water was filled in madpowder (polypropylene) for 24 hours.

3.1 g / L of Valeric Acid was added to the powder, and the final pH of the mixture was titrated to 4.7 using 1 NaOH aqueous solution.

The mixture was stirred for 5 minutes at 1000 rpm using a stirrer, and then a shaped body of wet foam type in which air was charged into the mixture was prepared.

The ceramic foam coating layer 120 was prepared by using a dip coating process on the sintered alumina support thus prepared.

The ceramic foam coating layer 120 and the alumina support were dried at 30 DEG C for 24 hours.

The sintering was carried out in an argon atmosphere at a temperature rising / falling rate of 1 占 폚 / min and holding at 1600 占 폚 for 2 hours.

The fracture surface and pore structure were measured using SEM (JSM + 5800, JEOL).

A ceramic foam coating layer 120 was prepared in the same manner as in Example 1. [

An alumina compact was used as a support for coating the ceramic foam coating layer 120 thus manufactured.

Alumina powder (AKP-30) was molded into a uniaxial pressing press, and then the ceramic foam coating layer 120 was coated, dried and sintered in the same manner as in Example 1 without sintering.

This suppresses the occurrence of cracks in the ceramic foam coating layer 120 by reducing the difference in shrinkage ratio between the ceramic foam coating layer 120 and the support 140 during sintering.

FIG. 3 shows a scanning electron microscope (SEM) photograph of a ceramic foam for forming a ceramic coating layer, which is a main component of the ceramic material according to the present invention.

As shown in the figure, it is confirmed that the ceramic foam for forming the ceramic foam coating layer 120 is manufactured by the colloid particle stabilization method to form a cellular pore structure.

4 is a scanning electron microscope (SEM) photograph showing an embodiment of the ceramic material according to the present invention. FIG. 5 is a cross-sectional view of the ceramic material according to the present invention, An electron microscope (SEM) photograph is shown.

As shown in these drawings, the ceramic foam coating layer 120 including the pores 122 is stably bonded to the upper surface of the support 140 by the coated ceramic foam, and in the process of bonding, As shown in FIG.

100 ..... Ceramic material 120 ..... Ceramic foam coating layer
122 ..... pore 140 ..... support
S100 ..... Support forming step S200 ..... Material preparation step
S300 ..... Ceramic foam forming step S400 ..... Ceramic foam coating step
S500 ..... Drying step S600 ..... Sintering step

Claims (9)

A support formed of a ceramic material,
And a ceramic foam coating layer coated on one side of the support,
The ceramic foam coating layer comprises
A ceramic material coated with a colloid particle-stabilized ceramic foam, which is produced by a colloid particle stabilization method and has a cell-type pore structure.
The method of claim 1, wherein the ceramic foam coating layer comprises:
Wherein the coating is formed by any one of spin coating, pressure casting, slip casting and dip-coating processes. Ceramic material.
The method of claim 1, wherein the ceramic foam coating layer comprises:
A ceramic material coated with a colloid particle-stabilized ceramic foam, wherein the ceramic material has a thickness of 0.1 to 50 mm.
The method according to claim 1,
Wherein the support is formed by sintering a ceramic foam coated with a colloid particle stabilized ceramic foam.
The method according to claim 1,
Wherein the support and the ceramic foam coating layer are coated with a colloidal particle-stabilized ceramic foam that is directly connected by diffusion bonding through solid-state diffusion.
The method according to claim 1,
Wherein the ceramic foam coating layer has a porosity of 80 to 95%.
The method according to claim 1,
The support and the ceramic foam coating layer is aluminum nitride (AlN), silicon nitride (Si ₃ N _4), silicon carbide (SiC), zirconium carbide (ZrC), tungsten carbide (WC), alumina (Al ₂ O _3), cordierite Wherein the ceramic material is formed by using a single powder of one of cordierite, mullite, and zirconia (ZrO ₂ ) or one or more composite powders.
A support forming step of forming a ceramic material support by a method other than sintering or sintering;
Preparing a raw material powder having the same composition as the support and a surfactant;
Preparing a ceramic foam by mixing a raw material powder prepared in the material preparation step with water to form a mixture, and adding a surfactant to prepare a colloidal particle stabilized foam;
A ceramic foam coating step of coating a ceramic foam produced in the ceramic foam manufacturing step on one side of the support formed in the support forming step to form a coating layer;
A drying step of drying the support and the ceramic foam coating layer and
And a sintering step of sintering the dried support and the ceramic foam coating layer,
In the support forming step,
Aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ), silicon carbide (SiC), zirconium carbide (ZrC), tungsten carbide (WC), alumina (Al ₂ O ₃ ), cordierite, mullite ), Zirconia (ZrO ₂ ), or a composite powder of at least one of the composite powders, wherein the support is formed by coating a colloidal particle-stabilized ceramic foam.
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