JP2012171824A - Silicon carbide-based heat-resistant ultra-lightweight porous structure material, and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silicon carbide-based heat-resistant ultra-lightweight porous structure material excellent in oxidation resistance and corrosion resistance.SOLUTION: First slurry containing resins and silicon powder is impregnated into a shaped skeleton of an organic porous structure, to be carbonized in a vacuum or inactive atmosphere, and reactively sintered in the vacuum or inactive atmosphere to be converted into silicon carbide, and silicon is melted and impregnated to form a silicon-covered layer; and then, second slurry containing resins is impregnated to be carbonized, and at least the surface of the silicon-covered layer is converted into silicon carbide.

Description

  The present invention is an ultra-lightweight material that maintains a continuous porous shape such as sponge, woven fabric, non-woven fabric, and corrugated cardboard by a two-step reaction sintering method in which silicon is melt impregnated after reaction sintering of silicon and carbon. The present invention relates to a silicon carbide-based heat resistant ultralight porous structure material and a method for producing the same, and more specifically, a high temperature filter, a high temperature structure member, a heat insulating material, a molten metal filter material, a burner plate, a heater material, The present invention relates to a heat-resistant ultralight porous structure material suitable for many uses such as a high-temperature silencer and a method for producing the same.

  Since silicon carbide-based ceramics are lightweight and have excellent heat resistance, wear resistance, corrosion resistance, etc., in recent years, for example, high-temperature corrosion-resistant members, heater materials, wear-resistant members, as well as abrasives, grindstones, etc. Widely used in applications. Since this silicon carbide ceramic is mainly manufactured by a sintering technique, it has not yet been put into practical use as a filter-shaped ultralight porous material having a porosity of 90% or more.

Recently, research on such heat-resistant lightweight porous ceramics has begun. For example, as a ceramic foam filter for cast iron, Bridgestone Corp. impregnates a silicon carbide powder slurry into a polyethylene or polyurethane sponge, removes the excess slurry, and dries and fires to obtain a porous silicon carbide structure. The physical properties in the catalog indicate that the porosity is 85% and the apparent specific gravity is about 0.42 g / cm ³ .

However, since the silicon carbide powder slurry is used in the above-described method, there are places where the surplus slurry closes the remaining pores even if the surplus slurry is removed. Basically, it is made by the powder sintering method of ceramics, so the center part of the sponge skeleton part becomes hollow without entering powder, and if the amount of powder attached to the skeleton part is small, the strength becomes low, so the skeleton part It becomes thicker than the sponge skeleton. In addition, the porosity is as low as about 85%, and the apparent specific gravity is as high as about 0.42 g / cm ³ . Also, the pore diameter is as large as about 1 to 5 mm (standard number of cells: 13/25 mm to 6 / mm).

  Therefore, the inventors of the present invention, in the study of the fiber reinforced silicon carbide composite material, the dense amorphous carbon-only matrix formed by the carbonization of the phenol resin hardly reacts with the molten silicon, but the mixture of the silicon powder and the phenol resin is reacted and sintered. It has been found that silicon carbide produced by (volume reduction reaction) has good wettability with molten silicon, and that molten silicon can easily permeate and react with a porous residual amorphous carbon matrix. 2000-313676).

  As a result of further earnest research on the silicon carbide-based heat-resistant ultralight porous structure material, a tangible skeleton of a porous structure such as sponge was impregnated with silicon powder and resin, and silicon powder and carbon from the structure were A silicon carbide-based heat-resistant ultralight porous structure material is produced by generating porous silicon carbide and residual carbon by a silicon carbide formation reaction accompanied by a volume reduction of silicon, and then performing melt impregnation of silicon on the porous skeleton. It was found that even a complex shape can be easily produced while maintaining the shape of the tangible skeleton of the porous structure (Japanese Patent No. 3699992) (Japanese Patent Laid-Open No. 2010-30888) .

  Further, when this method is used for a porous structure made of wood, paper, plastic or carbon powder, it is impregnated with resin and silicon powder, and after carbonization, silicon powder is reacted and sintered, and silicon is melted and impregnated. Thus, it has been found that a silicon carbide-based heat-resistant lightweight porous structural material can be easily produced while maintaining the shape of the tangible skeleton of the porous structure even if it has a complicated shape. In particular, when a porous structure containing carbon powder is used, impregnation with resin alone may be performed without adding silicon powder. This is because when the porous structure contains a large amount of carbon powder, silicon can be melt-impregnated even if silicon powder is not contained (Japanese Patent No. 4110244).

JP 2000-313676 Patent No. 3699992 JP 2010-30888 Patent No. 4110244

  When a silicon carbide-based heat-resistant ultralight porous structural material is manufactured by the manufacturing method described in Patent Documents 1-4, most of the surface is covered with metallic silicon because silicon is melt-impregnated in the final process. Yes. However, since metal silicon has lower oxidation resistance and corrosion resistance than silicon carbide, this silicon carbide heat-resistant ultralight porous structure material is used as a diesel particulate filter (DPF) and a high-temperature filter that also requires corrosion resistance. There were difficulties in using it.

  The present invention has been made in view of such circumstances, and provides a silicon carbide-based heat-resistant ultralight porous structural material excellent in oxidation resistance and corrosion resistance, and the silicon carbide-based heat-resistant ultralight porous material. The object is to enable easy manufacture of structural materials.

A feature of the method for producing a silicon carbide-based heat-resistant ultralight porous structure material of the present invention that solves the above problems is an organic material formed from at least one material selected from resin, rubber, cloth, fiber, wood and paper After impregnating the tangible skeleton of the porous structure with the first slurry containing the resin as the carbon source and the silicon powder and removing the excess first slurry, it is 900 ° C. to 1300 ° C. in vacuum or in an inert atmosphere. A carbonization step of carbonizing to form a carbonized porous structure;
Silicon carbide is produced by reactive sintering of a carbonized porous structure at a temperature of 1300 ° C or higher in a vacuum or in an inert atmosphere, and at the same time, open pores resulting from a volume reduction reaction are produced, thereby producing a siliconized porous structure. A silicon carbide forming step to form a porous structure;
Silicon-coated porous structure is melt-impregnated with silicon at a temperature of 1300 ° C to 1800 ° C in a vacuum or in an inert atmosphere to make the residual carbon silicon carbide, and a silicon coating layer is formed on the surface to form a silicon-coated porous material. A melt impregnation step to form a porous structure;
A silicon-coated porous structure is impregnated with a second slurry containing resins as a carbon source to remove excess second slurry, and then heated to 900 ° C. to 1300 ° C. in a vacuum or an inert atmosphere for carbonization. At the same time, a surface silicon carbide forming step of siliconizing at least the surface of the silicon coating layer by reactive sintering at a temperature of 1300 ° C. to 1600 ° C. is performed in this order.

In addition, when the organic porous structure contains carbon powder, the characteristics of the manufacturing method of the silicon carbide heat-resistant ultralight porous structure material of the present invention are selected from resin, rubber, carbon powder, cloth, fiber, wood and paper A tangible skeleton of an organic porous structure formed of at least one material and containing carbon powder is impregnated with a first slurry containing a resin as a carbon source to remove excess first slurry, and then vacuum or A carbonization step of carbonizing at 900 ° C. to 1300 ° C. under an inert atmosphere to form a carbonized porous structure;
Silicon-coated porous structure is formed by melting and impregnating silicon at a temperature of 1300 ° C to 1800 ° C in a vacuum or inert atmosphere to form carbon coating on the surface and forming a silicon coating layer on the surface. A melt impregnation step to form a structure;
A silicon-coated porous structure is impregnated with a second slurry containing resins as a carbon source to remove excess second slurry, and then heated to 900 ° C. to 1300 ° C. in a vacuum or an inert atmosphere for carbonization. At the same time, a surface silicon carbide forming step of siliconizing at least the surface of the silicon coating layer by reactive sintering at a temperature of 1300 ° C. to 1600 ° C. is performed in this order.

  The feature of the silicon carbide heat-resistant ultralight porous structure material of the present invention produced by the production method of the present invention is that the pore structure corresponds to the pore structure of the organic porous structure used. It is in.

  In the silicon carbide heat-resistant ultralight porous structure material of the present invention, at least the surface of the silicon coating layer is siliconized. Therefore, since metal silicon is not exposed on the surface, it is excellent in oxidation resistance and corrosion resistance, and can be used as a diesel particulate filter (DPF) or a high-temperature filter.

  And according to the manufacturing method of the silicon carbide-based heat-resistant ultralight porous structure material of the present invention, since the second slurry is attached to the silicon-coated porous structure to perform carbonization and reaction sintering, The second slurry easily adheres to the silicon coating layer and reacts. Therefore, the entire surface of the silicon coating layer can be siliconized, and a silicon carbide-based heat-resistant ultralight porous structure material excellent in oxidation resistance and corrosion resistance can be easily manufactured.

In Example 1, it is a SEM photograph of the fracture surface of a silicon covering porous structure before performing a surface silicon carbide conversion process. 2 is a SEM photograph of a fracture surface of a silicon carbide heat-resistant ultralight porous structure material according to Example 1;

  In the manufacturing method according to claim 3, first, impregnation in which an organic porous structure is impregnated with a first slurry containing a resin as a carbon source and silicon powder or a first slurry further containing silicon carbide powder in this slurry. Perform the process. Here, as the organic porous structure, one having pores formed of at least one material selected from resin, rubber, carbon powder, cloth, fiber, wood and paper can be used. The shape, pore diameter, pore distribution, etc. are not particularly limited and can be variously selected according to the purpose. For example, examples of the organic porous structure made of resin include urethane foams such as sponge, foam rubber, and foamed polyolefin. Examples of the organic porous structure made of cloth include woven cloth, knitted cloth and non-woven cloth.

  Resins that are carbon sources may be those dissolved in a solvent to form a solution, and examples thereof include phenolic resins, furan resins, organometallic polymers such as polycarbosilane, or sucrose. One kind selected from these may be used, or a plurality of kinds may be mixed and used. Carbon powder, graphite powder and carbon black may be added as additives, and silicon carbide, silicon nitride, zirconia, zircon, alumina, silica, mullite, molybdenum disilicide, boron carbide as aggregates and antioxidants. Boron powder or the like can also be added.

  The silicon powder is preferably a fine powder having an average particle size of 30 μm or less. Those having a large particle size are preferably used after being pulverized by a ball mill or the like. The silicon powder may be a pure silicon powder, or a silicon alloy powder containing a metal such as Mg, Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, W, Alternatively, a mixed powder of pure silicon powder and these metal powders can be used.

  The mixing ratio of the resin and silicon powder in the first slurry is preferably in the range of Si / C = 0.05 to 5.00 in terms of atomic ratio. If this atomic ratio is less than 0.05, the amount of porous silicon carbide produced by reaction sintering is small, and impregnation with molten silicon becomes difficult. On the other hand, when the atomic ratio exceeds 5.00, the amount of silicon powder in the first slurry increases, and precipitation tends to occur.

  Moreover, the 1st slurry which mixed silicon carbide powder with the slurry containing resin and silicon powder can also be used. In this case, the silicon carbide powder is preferably within a range of 3 times the weight of the silicon powder. If the silicon carbide powder exceeds 3 times the weight of the silicon powder, mixing may be insufficient.

  The resin concentration, the silicon powder concentration, or the silicon carbide powder concentration in the first slurry is not particularly limited as long as the organic porous structure can be impregnated with the slurry. The solvent used for the slurry is not particularly limited, but a solvent capable of dissolving the resin is used.

  In order to impregnate the organic slurry with the first slurry, it may be simply dipped and pulled up, or it is preferably impregnated under reduced pressure. Then, excess slurry is removed from the organic porous structure. The reason why the excess first slurry is removed from the organic porous structure is to remove the first slurry filled in the continuous pores, and a method of sucking the excess slurry from the organic porous structure, or organic For example, the porous structure can be squeezed to remove excess slurry. By removing the excess slurry, a precursor is formed in which the slurry adheres to the inside or the surface of the organic porous structure.

  After the removing step, it is desirable to perform a drying step of drying the solvent in the slurry. The drying process can be performed in the atmosphere, and it is sufficient to hold at 70 ° C. for about 12 hours.

  In the carbonization step, the organic porous structure to which the first slurry is attached is carbonized at 900 ° C. to 1300 ° C. in a vacuum or an inert atmosphere to form a carbonized porous structure. In this carbonization step, the resins are carbonized and the organic porous structure is decomposed and burned off. As the inert atmosphere, an inert gas atmosphere such as argon gas is preferable. In the carbonization process by thermal decomposition of the resin, tar-like substances and vaporized substances are generated, so it is not preferable to carry out in a vacuum. Further, in a nitrogen gas atmosphere, silicon nitride may be generated, which is not preferable.

  As for the heating temperature in the silicon carbide conversion step, it is preferable to first heat in the range of 900 ° C to 1300 ° C for carbonization, and then to heat at a temperature of 1300 ° C or higher.

  Accordingly, after carbonization, a skeleton similar to the skeleton of the organic porous structure is formed of carbon and silicon powder or further silicon carbide powder. The carbon and silicon powder react by being heated to 1300 ° C. or more, and have a three-dimensional skeleton part mainly composed of silicon carbide and a continuous pore part formed between the three-dimensional skeleton part. A silicon carbide based porous structure that is not dense is formed. This reaction is a reaction in which volume is reduced because silicon and carbon are in the system, and carbon diffuses and reacts with silicon to form silicon carbide and simultaneously form fine pores inside the three-dimensional skeleton. Is done.

  In the next melt impregnation step, silicon carbide is melt impregnated into a silicon carbide porous structure at a temperature of 1300 ° C. to 1800 ° C. in a vacuum or an inert atmosphere to form a silicon coating layer. Form. This step may be performed by heating the metal silicon to a melting point (about 1410 ° C.) or higher to form molten silicon and impregnating the silicon carbide porous structure, and it is particularly preferable to perform in a vacuum. The melt-impregnating silicon may be in the form of powder, granules, or lumps.

  In the melt impregnation process, the molten silicon has good wettability to silicon carbide, so the molten silicon penetrates into the fine pores formed inside the three-dimensional skeleton and reacts with the remaining carbon to carbonize. Silicon is formed. This reaction is a reaction in which the volume increases because silicon is added from outside the system, and fine pores formed inside the three-dimensional skeleton are filled with silicon or silicon carbide. Accordingly, the strength of the three-dimensional skeleton is improved, and the adhesion strength between the silicon coating layer and the three-dimensional skeleton is significantly increased by the anchoring effect.

  In the melt impregnation step, the carbon is exposed to a high temperature of 1410 ° C. or higher in vacuum or in an inert atmosphere, so that all remaining carbon is silicon carbide. The melt impregnation step can be performed simultaneously with the silicon carbide conversion step. That is, first, carbonization is performed by heating in the range of 900 ° C. to 1300 ° C., and then silicon for melt impregnation is added and baked to 1300 ° C. or higher in a vacuum or an inert atmosphere to react silicon powder with carbon to form silicon carbide. A porous porous structure is produced and silicon is melted and impregnated at a temperature equal to or higher than the melting point of silicon.

  In the surface silicon carbide process, the silicon-coated porous structure is impregnated with a second slurry containing resins as a carbon source to remove excess second slurry, and then dried at 70 ° C. for about 12 hours, and then vacuum or vacuum is applied. By heating to 900 ° C. to 1300 ° C. in an active atmosphere for carbonization and reacting at a temperature of 1300 ° C. to 1600 ° C., at least the surface of the silicon coating layer is siliconized. The temperature during the reaction is desirably 1300 ° C. or higher and lower than the melting point of silicon.

  As the resins contained in the second slurry, those having many carbon atoms in the molecule and high wettability to the silicon coating layer are preferable. Examples of such resins include phenol resin, furan resin, sucrose and the like. However, when only the resin is included as the carbon source, the carbon that reacts with the silicon coating layer may be small, and therefore it is desirable that the second slurry contains carbon powder such as carbon black. The amount of the carbon powder in the second slurry is not particularly limited as long as it is in a viscosity range in which the silicon-coated porous structure can be impregnated as a slurry. Even if an excess of carbon powder is contained, the unreacted carbon powder is easily burned off by heating.

  As the carbon powder added to the second slurry, graphite, carbon black or the like can be used, and carbon black is particularly preferable from the viewpoint of reactivity with silicon and dispersibility.

  As for the application amount of the second slurry to the silicon-coated porous structure, it is desirable that the second slurry is applied thickly in order to increase the amount of resin when carbon powder is not included. When carbon powder such as carbon black is included, it can be applied relatively thinly depending on the content of carbon powder.

  The silicon carbide-based heat-resistant ultralight porous structural material of the present invention thus obtained has at least a surface of silicon carbide, such as a tangible skeleton surface and pore inner surfaces. Therefore, since metal silicon is not exposed on the surface, it is excellent in oxidation resistance and corrosion resistance.

  In the production method according to claim 4, except that an organic porous structure containing carbon powder is used, the silicon powder is not contained in the first slurry, and the silicon carbide step is not performed. It is the same as that of the manufacturing method as described in.

  The organic porous structure containing carbon powder is formed of at least one material selected from resin, rubber, carbon powder, cloth, fiber, wood, and paper. For example, formed from resin containing carbon powder, rubber containing carbon powder, cloth containing carbon powder (woven fabric, nonwoven fabric, knitted fabric), fiber assembly containing carbon powder, wood containing carbon powder, paper containing carbon powder, etc. can do. Alternatively, a carbon product obtained by adding a binder to carbon powder and forming the carbon powder into a honeycomb shape, a cardboard shape, or a cardboard shape may be used.

  Amorphous carbon obtained by carbonizing a resin hardly reacts with molten silicon when it is in a dense state. However, the carbonized porous structure formed in the carbonization process is porous. The carbon powder contained in the carbonized porous structure has good wettability with molten silicon and directly reacts with silicon to produce silicon carbide.

  Therefore, in the manufacturing method according to claim 4, the first slurry does not contain silicon powder, and the melt impregnation step is performed without performing the silicon carbide step after the carbonization step. In addition, also in the manufacturing method of Claim 4, it cannot be overemphasized that a silicon powder may be included in a 1st slurry and a silicon carbide formation process may be performed.

  Hereinafter, the present invention will be described specifically by way of examples.

  The mixing ratio of the phenol resin and silicon powder with an average particle size of about 20μm is set to the ratio that the carbon / silicon atomic ratio of carbonization of the phenol resin becomes Si / C = 0.6, which is about 1.5 times the weight of the silicon powder. Prepare a slurry by dissolving phenol resin with heavy ethyl alcohol, and ball mill mix for 1 day to reduce the particle size of silicon powder, and add silicon carbide powder with an average particle size of about 3 μm in the same weight as silicon powder. A first slurry was prepared.

<Impregnation step>
Prepare # 13 (13 cells per inch) polyurethane sponge, fully impregnated with the above first slurry, squeezed to the extent that the first slurry liquid does not block the continuous pores, then at 70 ° C for 12 hours, Dried. At this time, the sponge expanded about 20% in the axial direction.

<Carbonization process, silicon carbide conversion process, melt impregnation process>
The sponge with the slurry adhered thereto was carbonized by heating to 1000 ° C. under an argon gas atmosphere. At this time, the sponge was decomposed and burned, and the phenol resin was carbonized to form a carbonized porous structure having the same skeleton as the sponge used. The sponge contracted during carbonization, and was slightly smaller with about 12% contraction in the axial direction than before carbonization.

  Silicon granules having substantially the same weight as the carbonized porous structure were added to the carbonized porous structure and fired at 1450 ° C. for 1 hour in a vacuum. In this firing, carbon reacts with silicon powder at a temperature lower than the melting point of silicon (about 1410 ° C.) to form a silicon carbide porous structure composed of sponge-like silicon carbide and unreacted carbon. . When the temperature is equal to or higher than the melting point of silicon, silicon granules are melt-impregnated into the silicon carbide porous structure and react with the remaining carbon to finally obtain a silicon-coated porous structure having a silicon coating layer.

  FIG. 1 shows an image obtained by cutting out a part of the skeleton of the obtained silicon-covered porous structure and observing the surface with an SEM reflected electron image. In FIG. 1, the white part is silicon and the gray part is silicon carbide.

<Surface silicon carbide process>
A second slurry was prepared by mixing 5 g of phenol resin, 0.5 g of carbon black, and 10 g of ethyl alcohol. The silicon-coated porous structure is immersed in this second slurry, pulled up to remove the excess second slurry, dried at 70 ° C. for 12 hours, then carbonized at 1000 ° C. in an argon atmosphere, and vacuumed For 1 hour at 1450 ° C.

  The coating layer of the second slurry formed by this carbonization treatment was carbonized on the surface, and then carbon and silicon reacted on the surface of the silicon coating layer to form a silicon carbide layer.

  FIG. 2 shows an image obtained by cutting out a part of the skeleton of the obtained silicon carbide heat-resistant ultralight porous structure material and observing the fracture surface with a SEM reflected electron image. Although some carbon (black part) remains on the surface, there is silicon carbide (gray part) inside, and there is a mixed state of silicon carbide (gray part) and silicon (white part) inside.

That is, the obtained silicon carbide-based heat-resistant ultralight porous structure material is composed of silicon carbide on the surface of the skeleton and continuous pores, has the same structure as the sponge used, has a pore diameter of 500 to 600 μm, an open porosity of 97%, and a density 0.07 g / cm ³ , and no collapsed pores were found.

  Using the same sponge as in Example 1, the impregnation step, the carbonization step, the silicon carbide step, and the melt impregnation step were performed in the same manner as in Example 1. Next, a second slurry consisting of 5 g of phenol resin and 10 g of ethyl alcohol and containing no carbon black was used, and the silicon-coated porous structure was immersed in this second slurry and pulled up to obtain an extra second slurry. The surface silicon carbide conversion step was performed in the same manner as in Example 2 except that the step of drying at 70 ° C. for 12 hours was repeated three times to deposit the second slurry thickly.

  The obtained silicon carbide heat-resistant ultralight porous structural material had the same structure as in Example 1, and the entire surface was composed of silicon carbide.

  Using the same sponge as in Example 1, the impregnation step, the carbonization step, the silicon carbide step, the melt impregnation step, and the surface silicon carbide step were performed in the same manner as in Example 1. However, the treatment temperature of the surface silicon carbide process was 1350 ° C.

  The obtained silicon carbide heat-resistant ultralight porous structural material had the same structure as in Example 1, and the entire surface was composed of silicon carbide.

  An impregnation step and a carbonization step were performed in the same manner as in Example 1 using a laminated corrugated cardboard made of activated carbon powder instead of the polyurethane sponge. However, the first slurry does not contain silicon powder or silicon carbide powder. The obtained carbonized porous structure was strong enough to be processed, and the shrinkage was as small as about 3%. This carbonized porous structure was subjected to silicon melt impregnation at 1450 ° C. for 1 hour under vacuum to obtain a corrugated silicon-coated porous structure.

  A surface silicon carbide conversion step was performed on the silicon-coated porous structure in the same manner as in Example 3. The obtained silicon carbide-based heat resistant ultralight porous structure had a laminated corrugated cardboard structure made of activated carbon powder, and the entire surface was composed of silicon carbide.

  The silicon carbide heat-resistant ultralight porous structural material of the present invention is used for many applications such as high-temperature filters, high-temperature structural members, heat insulating materials, molten metal filter media, burner plates, heater materials, and high-temperature silencers. Can do.

Claims (10)

A tangible skeleton of an organic porous structure formed of at least one material selected from resin, rubber, cloth, fiber, wood and paper is impregnated with a first slurry containing resins as a carbon source and silicon powder. Removing the excess first slurry and then carbonizing at 900 ° C. to 1300 ° C. in a vacuum or under an inert atmosphere to form a carbonized porous structure;
The carbonized porous structure is subjected to reactive sintering at a temperature of 1300 ° C. or higher in a vacuum or an inert atmosphere to generate silicon carbide, and at the same time, open pores resulting from a volume reduction reaction are generated to form silicon carbide. A siliconization step to form a porous structure;
The silicon carbide porous structure is melt-impregnated with silicon at a temperature of 1300 ° C. to 1800 ° C. in a vacuum or in an inert atmosphere so that residual carbon is silicon carbide and a silicon coating layer is formed on the surface to cover the silicon A melt impregnation step to form a porous structure;
After impregnating the silicon-coated porous structure with a second slurry containing resins as a carbon source and removing the excess second slurry, the carbon is heated to 900 ° C. to 1300 ° C. in a vacuum or under an inert atmosphere. And a silicon carbide-based heat-resistant superficial silicon carbide step formed by carrying out reaction sintering at a temperature of 1300 ° C to 1600 ° C to siliconize at least the surface of the silicon coating layer. A lightweight porous structural material,
A silicon carbide-based heat-resistant ultralight porous structural material, wherein the pore structure of the silicon carbide-based heat-resistant ultralight porous structure material is a structure corresponding to the pore structure of the organic porous structure. A tangible skeleton of an organic porous structure formed of at least one material selected from resin, rubber, carbon powder, cloth, fiber, wood, and paper, and containing carbon powder. A carbonization step of impregnating the slurry and removing the excess first slurry, followed by carbonization at 900 ° C. to 1300 ° C. in a vacuum or an inert atmosphere to form a carbonized porous structure;
The carbonized porous structure is melt-impregnated with silicon at a temperature of 1300 ° C. to 1800 ° C. in a vacuum or in an inert atmosphere so that the residual carbon becomes silicon carbide and a silicon coating layer is formed on the surface to form a silicon-coated porous material. A melt impregnation step to form a porous structure;
After impregnating the silicon-coated porous structure with a second slurry containing resins as a carbon source and removing the excess second slurry, the carbon is heated to 900 ° C. to 1300 ° C. in a vacuum or under an inert atmosphere. And a silicon carbide-based heat-resistant superficial silicon carbide step formed by carrying out reaction sintering at a temperature of 1300 ° C to 1600 ° C to siliconize at least the surface of the silicon coating layer. A lightweight porous structural material,
A silicon carbide-based heat-resistant ultralight porous structural material, wherein the pore structure of the silicon carbide-based heat-resistant ultralight porous structure material is a structure corresponding to the pore structure of the organic porous structure. A tangible skeleton of an organic porous structure formed of at least one material selected from resin, rubber, cloth, fiber, wood and paper is impregnated with a first slurry containing resins as a carbon source and silicon powder. Removing the excess first slurry and then carbonizing at 900 ° C. to 1300 ° C. in a vacuum or under an inert atmosphere to form a carbonized porous structure;
The carbonized porous structure is subjected to reactive sintering at a temperature of 1300 ° C. or higher in a vacuum or an inert atmosphere to generate silicon carbide, and at the same time, open pores resulting from a volume reduction reaction are generated to form silicon carbide. A siliconization step to form a porous structure;
The silicon carbide porous structure is melt-impregnated with silicon at a temperature of 1300 ° C. to 1800 ° C. in a vacuum or in an inert atmosphere so that residual carbon is silicon carbide and a silicon coating layer is formed on the surface to cover the silicon A melt impregnation step to form a porous structure;
After impregnating the silicon-coated porous structure with a second slurry containing resins as a carbon source and removing the excess second slurry, the carbon is heated to 900 ° C. to 1300 ° C. in a vacuum or under an inert atmosphere. And a silicon carbide-based heat-resisting process characterized by performing in this order a surface silicon carbide conversion step in which at least the surface of the silicon coating layer is silicon carbide by reaction sintering at a temperature of 1300 ° C. to 1600 ° C. For producing a porous ultralight porous structural material. A tangible skeleton of an organic porous structure formed of at least one material selected from resin, rubber, carbon powder, cloth, fiber, wood, and paper, and containing carbon powder. A carbonization step of impregnating the slurry and removing the excess first slurry, followed by carbonization at 900 ° C. to 1300 ° C. in a vacuum or an inert atmosphere to form a carbonized porous structure;
The carbonized porous structure is melt-impregnated with silicon at a temperature of 1300 ° C. to 1800 ° C. in a vacuum or in an inert atmosphere so that the residual carbon becomes silicon carbide and a silicon coating layer is formed on the surface to form a silicon-coated porous material. A melt impregnation step to form a porous structure;
After impregnating the silicon-coated porous structure with a second slurry containing resins as a carbon source and removing the excess second slurry, the carbon is heated to 900 ° C. to 1300 ° C. in a vacuum or under an inert atmosphere. And a silicon carbide-based heat-resisting process characterized by performing in this order a surface silicon carbide conversion step in which at least the surface of the silicon coating layer is silicon carbide by reaction sintering at a temperature of 1300 ° C. to 1600 ° C. For producing a porous ultralight porous structural material.   The silicon carbide-based heat resistance according to claim 3, wherein the first slurry contains the resins and the silicon powder so that an atomic ratio of silicon to carbon becomes a ratio of Si / C = 0.05 to 5.00. A method for producing an ultralight porous structure.   The method for producing a silicon carbide-based heat resistant ultralight porous structure according to claim 3 or 4, wherein the second slurry contains carbon black.   5. The silicon carbide-based heat resistant ultralight porous material according to claim 3, wherein the resin contained in the first slurry is at least one selected from a phenol resin, a furan resin, an organometallic polymer, and sucrose. A method for producing a structural material.   5. The silicon carbide-based heat-resistant ultralight porous material according to claim 3, wherein the first slurry contains one or more selected from carbon powder, graphite powder, and carbon black as an additive. A method for producing a structural material.   The first slurry includes at least one selected from the group consisting of silicon carbide, silicon nitride, zirconia, zircon, alumina, silica, mullite, molybdenum disilicide, boron carbide, and boron powder as an aggregate or an antioxidant. The manufacturing method of the silicon carbide type heat resistant ultralight porous structure material of Claim 3 or Claim 4 added.   The first slurry further includes silicon powder, and the carbonized porous structure is heated at a temperature of 1300 ° C. or higher in a vacuum or an inert atmosphere between the carbonization step and the melt impregnation step. 5. The silicon carbide heat-resistant heat treatment according to claim 4, wherein silicon carbide is formed by reaction sintering, and at the same time, an open pore resulting from a volume reduction reaction is generated to form a silicon carbide porous structure. For producing a porous ultralight porous structural material.