KR20180130164A - A compostion for preparing a liquid phase sintered silicon carbide porous body, the liquid phase sintered silicon carbide porous body using the composition having high strength and resistivity and a method for manufacturing thereof - Google Patents

Abstract

The present invention relates to a composition including a sintering aid containing silicon carbide and an element selected from aluminum (Al), silicon (Si), yttrium (Y), and combinations thereof, a silicon carbide porous body produced by the composition, and a manufacturing method thereof. More specifically, a sintering aid containing an element selected from aluminum (Al), silicon (Si), yttrium (Y), and combinations thereof is prepared. The sintering aid and silicon carbide are mixed at a predetermined ratio to prepare a mixed powder. A silicon carbide molded product formed of the mixed powder is sintered at a low temperature of 1,400 to 1,600°C to obtain a silicon carbide pore body having a porosity of 40% or more, an average pore size of 1 to 50 μm, a constant pore size distribution, three-point bending strength of 45 MPa or more, and a volume resistivity of 10^8 Ω·cm or more. An object of the present invention is to provide the silicon carbide porous body which simultaneously satisfies high porosity, ease of controlling the average pore size, excellent bending strength, and volume resistance.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a liquid phase sintered silicon carbide porous body having high strength and high resistance characteristics and a method for producing the same. BODY USING THE COMPOSITION HAVING HIGH STRENGTH AND RESISTIVITY AND METHOD FOR MANUFACTURING THEREOF}

The present invention relates to a composition comprising a sintering assistant containing silicon carbide and an element selected from aluminum (Al), silicon (Si), yttrium (Y) and combinations thereof, a silicon carbide porous body made of the composition, .

Silicon carbide is excellent in thermal properties such as high temperature stability, thermal shock resistance and thermal conductivity, and excellent physical and chemical properties such as high temperature strength, corrosion resistance, chemical resistance and abrasion resistance, and is the most widely used fissile material It is a cargo-based ceramic material.

Among them, the silicon carbide porous body is a functional porous composite material using physicochemical properties of silicon carbide. It is a high temperature dust filter for the energy industry, a dust filter for a diesel engine, a dust filter for a diesel engine and the like, which are required to operate stably in a harsh environment such as a high temperature corrosive environment, Is used as a core material in various fields such as a catalyst carrier, a membrane separation membrane, a soundproofing material, a heat insulation material, and a vacuum chuck.

However, most studies on the silicon carbide porous body until now have been about porosity, pore size and fracture strength. Specifically, the average pore size is 1 to 50 μm, the volume resistance is high, the high strength and the high porosity are simultaneously satisfied There is no report on the patent and the technology for the silicon carbide porous body.

Korean Patent No. 10-0838825 (Patent Document 1) prepared reaction-sintered silicon carbide through infiltration of molten silicon. Patent Document 1 improves mechanical strength by mixing fibrous phases, but there is no information on the pore size distribution, and there is a limit that battery resistance is low due to residual silicon in the sintered body.

In addition, Korean Patent Laid-Open No. 10-2005-0063482 (Patent Document 2) discloses a process for producing a carbon black having a high bending strength by adding 0.3 to 0.5% by weight of aluminum boride and recrystallizing at a high temperature sintering temperature of 2,000 ° C. to 2200 ° C. A silicon porous body was prepared. However, in Patent Document 2, it is difficult to manufacture a porous article having a uniform pore size distribution and control the pore size, and there is a limit in that the economic efficiency is lowered as the heat treatment proceeds at a high temperature.

US 7,670,979 B2 (Patent Document 3) discloses a process for producing a shaped body by adding boron carbide powder as a sintering aid to a 1 to 10 탆 sized alpha silicon carbide powder, sintering the powder at 2,100 ° C to 2,300 ° C under an inert atmosphere, Mu m or less and a porosity of 45% to 65%. However, Patent Document 3 shows that a high resistance silicon carbide porous body having various pore sizes is not a technique capable of manufacturing economically high.

Korean Patent Laid-Open No. 10-2004-0104958 (Patent Document 4) reported a silicon carbide porous body for a filter using an oxide phase containing silicon carbide particles and metallic elements of silicon, aluminum, and alkaline earth metals as raw materials. However, in Patent Document 4, a silicon carbide porous body was produced by selecting an anosite, cordierite, mullite, or the like, and the bending strength was not satisfactory at 15 MPa to 30 MPa.

Japanese Patent Laid-Open Nos. 10-2000-0006202 and 10-2010-0077203 disclose a method of doping a nitrogen / boron atom to produce a silicon carbide sintered body having high electrical resistance and a method of doping nitrogen / The sintered recrystallized silicon carbide thus produced has been reported to be subjected to heat treatment in a state in which it is immersed in an aqueous solution of hydrogen fluoride. However, both of the patent documents have a disadvantage in that sintering must be carried out at a temperature of 1,900 캜 or higher. In particular, Patent Document 6 discloses a method of producing toxic fluorinated There is a disadvantage that an aqueous hydrogen solution must be additionally used.

It is inevitable to develop a technology for manufacturing a silicon carbide porous body having various sizes of pores, high porosity, excellent bending strength, excellent volume resistance, and high economic efficiency.

Korean Patent No. 10-0838825 Korean Patent Publication No. 10-2005-0063482 US 7,670,979 B2 Korean Patent Publication No. 10-2004-0104958 Korean Patent Publication No. 10-2000-0006202 Korean Patent Publication No. 10-2010-0077203

An object of the present invention is to provide a silicon carbide porous body which simultaneously satisfies a high porosity, an ease of controlling an average pore size, an excellent bending strength and a volume resistance.

Another object of the present invention is to provide a composition for use in producing a silicon carbide porous body having the above characteristics.

It is another object of the present invention to provide a method for producing a silicon carbide porous body having the above characteristics using the above composition.

The object of the present invention is not limited to the above-mentioned object. The object of the present invention will become more apparent from the following description, which will be realized by means of the appended claims and their combinations.

The composition for preparing a silicon carbide porous article according to the present invention is characterized by containing 5 vol% to 30 vol% of a sintering auxiliary containing 70 vol% to 95 vol% of silicon carbide and an element selected from aluminum (Al), silicon (Si), yttrium (Y) .

In a preferred embodiment of the present invention, the silicon carbide may have an average particle diameter of 5 탆 to 100 탆.

In a preferred embodiment of the present invention, the sintering aid may comprise 45% to 70% by weight of Al ₂ O ₃ , 5% to 25% by weight of SiO ₂ and 10% to 35% by weight of Y ₂ O ₃ have.

In a preferred embodiment of the present invention, the average particle size of the sintering aid may be smaller than the average particle size of the silicon carbide, specifically 0.05 to 0.7 times the average particle size of the silicon carbide.

The silicon carbide porous body according to the present invention comprises silicon carbide particles as an aggregate; And at least one selected from glassy ceramics, unreacted alumina particles and unreacted yttria particles located at the interface between the silicon carbide particles.

In a preferred embodiment of the present invention, the glassy ceramic may comprise an element selected from aluminum (Al), silicon (Si), yttrium (Y), and combinations thereof.

In a preferred embodiment of the present invention, the silicon carbide porous body has a porosity of 40% or more, an average pore size of 1 탆 to 50 탆, a 3-point bending strength of 45 MPa or more, and a volume resistivity of 10 ⁸ Ω · cm Or more.

The method for producing a silicon carbide porous body according to the present invention comprises the steps of preparing a sintering auxiliary containing an element selected from aluminum (Al), silicon (Si), yttrium (Y) and a combination thereof, 5 to 30 vol% And 70 vol.% To 95 vol.% Of silicon carbide to prepare a mixed powder, molding the mixed powder into a predetermined shape to produce a silicon carbide molded body, and sintering the silicon carbide molded body.

In a preferred embodiment of the present invention, the sintering assistant comprises 45 wt% to 70 wt% of Al ₂ O ₃ , 5 wt% to 25 wt% of SiO ₂ , and 10 wt% to 35 wt% of Y ₂ O _3, And then dried.

In a preferred embodiment of the present invention, the silicon carbide formed body can be manufactured by uniaxial pressing or hydrostatic pressing the mixed powder using a metal mold.

In a preferred embodiment of the present invention, the silicon carbide molded body can be sintered by heating it to 1,400 ° C to 1,600 ° C at an elevating rate of 1 to 20 ° C / min in an inert or oxidizing atmosphere and holding it for 1 to 4 hours.

In a preferred embodiment of the present invention, the porosity and average pore size of the silicon carbide porous body can be controlled through the average particle size of the silicon carbide and the sintering aid.

In a preferred embodiment of the present invention, the three-point bending strength of the silicon carbide porous body can be controlled through the content of the sintering aid, the average particle diameter of the silicon carbide, or the sintering temperature.

According to the present invention, it is possible to provide a silicon carbide porous body satisfying both high porosity, ease of controlling an average pore size, excellent bending strength and volume resistance.

Also, according to the present invention, the porosity, average pore size, bending strength, and volume resistance of the silicon carbide porous body can be easily adjusted according to the purpose.

In addition, since the present invention produces a silicon carbide porous body at a low sintering temperature, it can be a great help in securing price competitiveness.

The effects of the present invention are not limited to the effects mentioned above. It should be understood that the effects of the present invention include all reasonably possible effects in the following description.

1 is a result of analysis of the microstructure of the silicon carbide porous body according to the present invention by a scanning electron microscope.
Fig. 2 is a result of analyzing the components of particles located at a specific point (+) in Fig.
3 is a result of analysis of the microstructure of the silicon carbide porous body according to the present invention by a scanning electron microscope.
FIG. 4 is a result of analyzing the components of particles located at a specific point (+) in FIG.
5 shows the results of measurement of the air permeability of the silicon carbide porous body according to the present invention.
6 shows the results of measurement of the pore size distribution of the silicon carbide porous body according to the present invention.

Hereinafter, the present invention will be described in detail by way of examples. The embodiments of the present invention can be modified into various forms as long as the gist of the invention is not changed. However, the scope of the present invention is not limited to the following embodiments.

In the following description, well-known functions or constructions are not described in detail since they would obscure the invention. As used herein, " comprising "means that other elements may be included unless otherwise specified.

The composition for preparing a silicon carbide porous article according to the present invention (hereinafter referred to as a "composition") is a composition containing silicon carbide; And sintering aids containing elements selected from aluminum (Al), silicon (Si), yttrium (Y), and combinations thereof.

The composition includes silicon carbide and sintering aids because the silicon carbide is an ovoid-formed ceramic that forms strong covalent bonds.

When the silicon carbide porous body is formed using the above composition, the silicon carbide becomes an aggregate of a silicon carbide porous body, and the sintering auxiliary containing a specific element is composed of a vitreous ceramic positioned at an interface between particles of the silicon carbide forming an aggregate, As a result, the porosity, the average pore size, the bending strength and the volume resistance of the silicon carbide porous body can be improved or adjusted.

The silicon carbide may be any ordinary silicon carbide used for forming the silicon carbide porous body, but alpha-silicon carbide (? -SiC) may be preferably used.

The average particle diameter of the silicon carbide is not particularly limited, since it is determined according to the pore size required in the field in which the silicon carbide porous body is used, but is preferably 5 탆 to 100 탆, more specifically 30 탆 to 100 탆, Lt; RTI ID = 0.0 > um < / RTI > If the average particle diameter of the silicon carbide is less than 5 탆, the strength of the silicon carbide porous body may be weakened, and if it exceeds 100 탆, the porosity may be low and the average pore size may be small.

The sintering aid may contain an element selected from aluminum (Al), silicon (Si), yttrium (Y), and combinations thereof.

Specifically, the sintering aid may be an oxide powder selected from aluminum oxide (Al ₂ O ₃ ) powder, silicon oxide (SiO ₂ ) powder, yttrium oxide (Y ₂ O ₃ ) powder and combinations thereof, (Al ₂ O ₃₎ powder 25% by weight to 70% by weight, silicon oxide (SiO ₂₎ powder 5% to 25% by weight of yttrium oxide by weight of (Y ₂ O ₃₎ may comprise a powder of 10% by weight to 35% by weight have.

When the composition of the sintering auxiliary agent is as described above, a eutectic liquid phase of the sintering auxiliary agent is formed at a lower sintering temperature than the conventional sintering assistant agent to promote the sintering of the silicon carbide, and ceramic glassy matter and unreacted alumina Particles can coexist.

In preparing the sintering auxiliary agent, when the composition is prepared by appropriately adjusting the content of the sintering auxiliary agent and heat treatment is performed under appropriate conditions to form a silicon carbide porous body, unreacted alumina particles and / or unreacted yttria particles May be preferable for improving or controlling the porosity, the average pore size, the bending strength and the volume resistance of the porous silicon carbide article.

It is preferable that the sintering assistant has a size smaller than the average particle size of the silicon carbide. Specifically, a sintering auxiliary having an average particle size of 0.05 to 0.7 times the average particle diameter of the silicon carbide can be used. For this purpose, the average particle diameter of each component constituting the sintering auxiliary can be adjusted appropriately.

The composition may contain 70 vol% to 95 vol% of silicon carbide and 5 vol% to 30 vol% of sintering aids. When the composition has the above composition, the porosity, average pore size, bending strength and volume resistance of the silicon carbide porous body may be improved Can be adjusted.

The present invention also relates to a method for producing a silicon carbide porous body, specifically a liquid phase sintered silicon carbide porous body using the above composition, Preparing a sintering auxiliary containing an element selected from the group consisting of a combination of 5 vol% to 30 vol% of the sintering auxiliary and 70 vol% to 95 vol% of silicon carbide to prepare a mixed powder, molding the mixed powder into a predetermined shape Thereby producing a silicon carbide molded body, and sintering the silicon carbide molded body.

In the method for producing the silicon carbide porous body, among the detailed descriptions of the characteristics, contents, etc. of each component, those which are omitted below are as described above.

The preparation step of the sintering assistant is a step of mixing 25 wt% to 70 wt% of aluminum oxide (Al ₂ O ₃ ) powder, 5 wt% to 25 wt% of silicon oxide (SiO ₂ ) powder and 10 wt% of yttria (Y ₂ O ₃ ) % To 35% by weight in a solvent, or a dry process in which powders are mechanically mixed by a method such as milling and the like, followed by drying. In order to adjust the average particle diameter of the sintering aid, it is preferable to prepare the sintering auxiliary agent by pulverizing the dried powder and sieving the powder with a specific mesh.

The step of preparing the mixed powder is a step of uniformly mixing 5 vol% ~ 30 vol% of the sintering auxiliary and 70 vol% ~ 95 vol% silicon carbide by wet or dry method. At this time, a small amount of binder may be further added to the mixed powder. The binder is not particularly limited, but polyvinyl alcohol (PVA) having a concentration of 1% may be used, for example.

The step of preparing the silicon carbide molded article is a step of forming the mixed powder by uniaxial pressing or hydrostatic pressing using a metal mold to have a predetermined shape. The shape of the silicon carbide molded body is not particularly limited, and the silicon carbide molded body can be molded according to its application and purpose. However, it may be preferable to manufacture it so as to have a molding strength enough to allow movement. The silicon carbide molded body may be further subjected to a step of drying for a sufficient time before sintering.

The sintering step is a step of heating the silicon carbide formed body in an inert or oxidizing atmosphere at a temperature raising rate of 1 to 20 ° C / min to 1,400 ° C to 1,600 ° C and holding the silicon carbide molded body for 1 to 4 hours to obtain a silicon carbide porous body.

Since the composition according to the present invention includes a sintering aid having a specific composition, the sintering step can be performed at a low temperature of 1,400 ° C to 1,600 ° C. Accordingly, the silicon carbide porous body can be economically produced, which is advantageous in securing price competitiveness.

The silicon carbide porous body according to the present invention includes silicon carbide particles as an aggregate and glassy ceramics located at the interface between the silicon carbide particles and unreacted alumina particles.

The glassy ceramics originate from a sintering aid and may include an element selected from aluminum (Al), silicon (Si), yttrium (Y), and combinations thereof.

The silicon carbide porous body is produced by the above-described method using the above-mentioned composition, and has a porosity of 40% or more; An average pore size of 1 탆 to 50 탆; The three-point bending strength is at least 30 MPa, more preferably at least 45 MPa, more particularly at least 60 MPa; The volume resistance may be 10 ⁸ Ω · cm or more, more specifically 3.0 × 10 ⁸ Ω · cm or more, and more specifically 5.0 × 10 ⁸ Ω · cm or more.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, these examples are for illustrating the present invention and the scope of the present invention is not limited thereto.

Example 1

(1) Preparation step of sintering auxiliary agent

The aluminum oxide (Al ₂ O ₃ ) powder, the silicon oxide (SiO ₂ ) powder and the yttria (Y ₂ O ₃ ) powder were weighed so as to have the contents as shown in Table 1, and then an alumina jar Respectively. The average particle diameters of the aluminum oxide (Al ₂ O ₃ ) powder, the silicon oxide (SiO ₂ ) powder and the yttria (Y ₂ O ₃ ) powder were 0.5 μm, 7 μm and 36 μm, respectively. The oxide powder was sufficiently dispersed and mixed at a rate of about 200 RPM using alumina balls at room temperature for about 12 hours. Lt; RTI ID = 0.0 > 60 C < / RTI > The dried powder was screened with 200 mesh to prepare a sintering auxiliary agent.

(2) Preparation of mixed powder

Silicon carbide and sintering auxiliary agent were prepared so as to have a vol% as shown in Table 1. As the silicon carbide, an alpha-silicon carbide powder having an average particle size of 65 μm was used. The silicon carbide and sintering aids were mixed mechanically homogeneously. At this time, 1% PVA solution was added and mixed in an amount of about 9 wt% based on the mass of the entire mixed powder to prepare a mixed powder.

(3) Production step of silicon carbide molded article

The mixed powder was charged into a mold mold having a diameter of 200 mm, molded by uniaxial pressing at a pressure of about 40 MPa, and dried at a temperature of about 60 캜 for about 24 hours to obtain a silicon carbide molded body.

(4) Sintering Step - Production of silicon carbide porous article

The silicon carbide molded body was placed in a graphite crucible coated with boron nitride (BN), and charged into a graphite vacuum furnace. The silicon carbide molded body was heated to 1,500 占 폚 at a heating rate of about 10 占 폚 / min in an argon gas atmosphere, and then heat-treated (sintered) for about 1 hour to obtain a silicon carbide porous body.

division Composition of sintering auxiliary [wt.%] The components [vol% (wt%)] Al ₂ O ₃ SiO ₂ Y ₂ O ₃ Sintering auxiliary Silicon carbide Psalm 1 58.6 23.0 18.4 15 (17.4) 85 (82.6) Psalm 2 58.7 23.0 18.3 20 (23.0) 80 (77.0) Psalm 3 57.8 23.6 18.6 25 (28.0) 75 (72.0) Psalm 4 58.7 23.0 18.3 30 (33.9) 70 (66.1)

(5) Scanning electron microscope analysis and component analysis of silicon carbide porous body

Fig. 1 is a microstructure obtained by analyzing a silicon carbide porous body according to the above-mentioned Specimen 1 with a scanning electron microscope. Fig. 2 is a result of analyzing the components of particles located at a specific point (+) in Fig. 2, aluminum (Al) and oxygen (O) atoms are analyzed as main components, although a trace amount of silicon (Si) element is detected. As a result, .

3 is a microstructure obtained by analyzing the silicon carbide porous body according to the above-mentioned Specimen 1 with a scanning electron microscope. FIG. 4 is a result of analyzing the components of particles located at a specific point (+) in FIG. Referring to FIG. 4, aluminum (Al), silicon (Si), yttrium (Y), and oxygen (O) are detected, and the material located at a specific point in FIG. 3 is glassy ceramic.

As a result, the silicon carbide porous body according to the present invention comprises silicon carbide particles constituting an aggregate; And glassy ceramics and unreacted alumina particles located at the interface between the silicon carbide grains.

(6) Measurement of air permeability of silicon carbide porous body

5 shows the results of measurement of the air permeability of the silicon carbide porous body according to the above-described Specimen 1. Fig. (Y-axis) of the air passing through the silicon carbide porous body linearly increases as the pressure of the air (x axis) injected into the silicon carbide porous body is increased, it is understood that the pores of the porous silicon carbide body are properly formed have.

(7) Measurement of physical properties of silicon carbide porous body

The three-point bending strength, porosity, average pore size, and volume resistance of the porous silicon carbide according to the test pieces 1 to 4 were measured.

The 3-point bending strength was measured by making a test piece having a size of 3 x 4 x 35 mm from a silicon carbide porous body. The apparent porosity was measured by the Archimedes method using the fractured specimen after measuring the bending strength. The average pore size was measured by mercury porosimetry and the volume resistivity at room temperature was measured. The results are shown in Table 2.

division Apparent porosity
[%] 3 point bending strength
[MPa] Volume resistance
[× 10 ⁸ Ω · cm] Average pore size
[Mu m] Psalm 1 42.5 38.0 4.98 18.22 Psalm 2 41.8 45.9 3.01 17.06 Psalm 3 40.2 46.2 3.02 17.69 Psalm 4 39.1 50.8 3.04 18.31

Referring to Table 2, the apparent porosity of the silicon carbide porous body according to the present invention was decreased as the content of the sintering assistant was increased (specimen 1 -> specimen 4), and the three point bending strength was greatly increased.

In order to improve the volume resistivity of the silicon carbide porous body, the metal oxide powder of a specific composition was used as a sintering auxiliary agent, and it was found that the volume resistance of the silicon carbide porous body was greatly improved to 10 ⁸ Ω · cm or more. Also, it can be confirmed that the volume resistivity is not significantly influenced by the content of the sintering auxiliary agent.

Example 2

A silicon carbide porous body was produced by the same composition and method as in Specimen 2 of Example 1 except that the sintering temperature in the sintering step was changed to 1,400 ° C and 1,600 ° C.

The three-point bending strength, porosity, average pore size and volume resistance of the obtained silicon carbide porous body were measured. The results are shown in Table 3.

Sintering temperature
[° C] Apparent porosity
[%] 3 point bending strength
[MPa] Volume resistance
[× 10 ⁸ Ω · cm] Average pore size
[Mu m] 1,400 42.8 31.2 4.99 14.70 1,500 41.8 45.9 3.01 17.06 1,600 40.5 64.3 3.12 22.09

Referring to Table 3, the apparent porosity was slightly increased and the three-point bending strength was greatly decreased as the sintering temperature was decreased to 1,400 ° C. Conversely, as the sintering temperature increased to 1,600 ℃, the apparent porosity decreased and the three point bending strength increased to 64.3 MPa.

However, the volume resistivity of the silicon carbide porous body did not show a large increase even when the sintering temperature was increased.

Example 3

A silicon carbide porous body having an average pore size of 10 탆 or less was prepared by the following method.

(1) Preparation step of sintering auxiliary agent

The aluminum oxide (Al ₂ O ₃ ) powder, the silicon oxide (SiO ₂ ) powder and the yttria (Y ₂ O ₃ ) powder were weighed so as to have the contents as shown in Table 4, and then an alumina jar containing an ethanol solvent Respectively. The average particle sizes of the aluminum oxide (Al ₂ O ₃ ) powder, the silicon oxide (SiO ₂ ) powder and the yttria (Y ₂ O ₃ ) powder were 0.5 μm, 4 and 9 μm, respectively. The oxide powder was sufficiently dispersed and mixed at a rate of about 200 RPM using alumina balls at room temperature for about 12 hours. Lt; RTI ID = 0.0 > 60 C < / RTI > The dried powder was screened with 200 mesh to prepare a sintering auxiliary agent.

(2) Preparation of mixed powder

Silicon carbide and sintering auxiliary agent were prepared so as to have a vol% as shown in Table 4. As the silicon carbide, an alpha-silicon carbide powder having an average particle diameter of 30 mu m was used. The silicon carbide and sintering aids were mixed mechanically homogeneously. At this time, 1% PVA solution was added and mixed in an amount of about 9 wt% based on the mass of the entire mixed powder to prepare a mixed powder.

(3) Production step of silicon carbide molded article

The mixed powder was charged into a mold mold having a diameter of 50 mm, uniaxially pressed at a pressure of about 40 MPa, and dried at a temperature of about 60 캜 for about 24 hours to obtain a silicon carbide molded article.

(4) Sintering Step - Production of silicon carbide porous article

The silicon carbide molded body was placed in a graphite crucible coated with boron nitride (BN), and charged into a graphite vacuum furnace. The silicon carbide molded body was heated to 1,500 占 폚 at a heating rate of about 10 占 폚 / min in an argon gas atmosphere, and then heat-treated (sintered) for about 1 hour to obtain a silicon carbide porous body.

division Composition of sintering auxiliary [wt.%] The components [vol% (wt%)] Al ₂ O ₃ SiO ₂ Y ₂ O ₃ Sintering auxiliary Silicon carbide Psalm 5 58.6 23.0 18.4 15 (17.4) 85 (82.6) Psalm 6 58.7 23.0 18.3 20 (23.0) 80 (77.0) Psalm 7 57.8 23.6 18.6 25 (28.0) 75 (72.0)

(5) Measurement of pore size distribution of porous silicon carbide

6 shows the results of measurement of the pore size distribution of the silicon carbide molded body of the above-mentioned Specimen 5 by mercury porosimetry. As a result, it can be seen that the pore size distribution, which is not widely spread, is uniformly formed at a uniform size.

(6) Measurement of physical properties of silicon carbide porous body

The three-point bending strength, porosity, average pore size and volume resistance of the silicon carbide porous body according to Specimen 5 to Specimen 7 were measured. The results are shown in Table 5.

division Apparent porosity
[%] 3 point bending strength
[MPa] Volume resistance
[× 10 ⁸ Ω · cm] Average pore size
[Mu m] Psalm 5 43.3 60.21 4.95 7.85 Psalm 6 42.9 62.22 5.97 7.81 Psalm 7 41.9 64.72 5.01 7.46

Referring to Table 5, it can be seen that the average pore size of the silicon carbide porous body is 10 μm or less. It can be seen that the average pore size of the silicon carbide porous body can be controlled as desired by adjusting the average particle diameter of the silicon carbide and the average particle size of the raw material of the sintering auxiliary agent.

As shown in Table 5, the apparent porosity of the porous silicon carbide decreased as the content of the sintering aid increased. As the average particle diameter of the silicon carbide powder used as the aggregate decreased, the three-point bending strength increased greatly to over 60 MPa . However, volume resistance did not change much.

It was confirmed through the above Examples 1 to 3 that the porous silicon carbide porous body having excellent porosity and average pore size can be easily controlled and 3-point bending strength and volume resistance can be remarkably improved.

It was also confirmed that the porosity and the average pore size of the silicon carbide porous body can be controlled by controlling the average particle size of the silicon carbide and the sintering aid.

Also, it was confirmed that the three point bending strength of the silicon carbide porous body can be controlled by adjusting the content of the sintering auxiliary agent, the average particle diameter of the silicon carbide, and the sintering temperature.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the scope of the present invention is not limited to the disclosed exemplary embodiments. Various modifications and improvements of those skilled in the art are also within the scope of the present invention.

The silicon carbide porous body according to the present invention can be applied not only to the electronic / semiconductor industry such as a vacuum chuck material for a semiconductor / display industry process, but also to a wide range of industrial fields such as a high temperature dust filter material for a refinery / power generation industry and a diesel vehicle dust filter material.

Claims (19)

70 vol% to 95 vol% of silicon carbide; And
And 5 vol% to 30 vol% of a sintering auxiliary containing an element selected from aluminum (Al), silicon (Si), yttrium (Y), and combinations thereof.
The method according to claim 1,
Wherein the silicon carbide has an average particle diameter of 5 mu m to 100 mu m.
The method according to claim 1,
The sintering aid
45% by weight to 70% by weight of Al ₂ O ₃ ;
5 wt% to 25 wt% of SiO ₂ ; And
And 10 wt% to 35 wt% of Y ₂ O ₃ .
The method according to claim 1,
Wherein the average particle diameter of the sintering auxiliary agent is smaller than the average particle diameter of the silicon carbide.
The method according to claim 1,
Wherein the average particle diameter of the sintering auxiliary agent is 0.05 to 0.7 times the average particle diameter of the silicon carbide.
Silicon carbide particles as aggregates; And
A silicon carbide porous body containing at least one of glassy ceramics, unreacted alumina particles, and yttria particles located at an interface between the silicon carbide grains.
The method according to claim 6,
Wherein the glassy ceramic comprises an element selected from aluminum (Al), silicon (Si), yttrium (Y), and combinations thereof.
The method according to claim 6,
Wherein the silicon carbide porous body has a porosity of 40% or more and an average pore size of 1 to 50 占 퐉.
The method according to claim 6,
Wherein the silicon carbide porous body has a three-point bending strength of 45 MPa or more.
The method according to claim 6,
Wherein the silicon carbide porous body has a volume resistivity of 10 < ⁸ > OMEGA .cm or more.
Preparing a sintering auxiliary comprising an element selected from aluminum (Al), silicon (Si), yttrium (Y), and combinations thereof;
Mixing 5 vol% to 30 vol% of the sintering aid and 70 vol% to 95 vol% silicon carbide to prepare a mixed powder;
Molding the mixed powder into a predetermined shape to produce a silicon carbide molded body; And
And sintering the silicon carbide formed body.
12. The method of claim 11,
The sintering aid may be prepared by mixing 45 wt% to 70 wt% of Al ₂ O ₃ , 5 wt% to 25 wt% of SiO ₂ , and 10 wt% to 35 wt% of Y ₂ O _3, Wherein the sintering aid is a process for producing a silicon carbide porous article.
12. The method of claim 11,
Wherein the silicon carbide is an alpha silicon carbide having an average particle diameter of 5 to 100 占 퐉.
12. The method of claim 11,
Wherein the average particle diameter of the sintering assistant is 0.05 to 0.7 times the average particle diameter of the silicon carbide.
12. The method of claim 11,
Wherein the silicon carbide formed body is manufactured by uniaxial pressing or hydrostatic pressing the mixed powder using a metal mold.
12. The method of claim 11,
Wherein the silicon carbide formed body is heated in an inert or oxidizing atmosphere at a temperature raising rate of 1 to 20 占 폚 / min to 1,400 to 1,600 占 폚 and held for 1 to 4 hours to sinter the silicon carbide formed body.
12. The method of claim 11,
Wherein the porosity and the average pore size of the silicon carbide porous body are controlled by controlling an average particle size of the silicon carbide and the sintering auxiliary agent.
12. The method of claim 11,
Wherein the three-point bending strength of the silicon carbide porous body is controlled by controlling the content of the sintering auxiliary agent, the average particle diameter of the silicon carbide, or the sintering temperature.
12. The method of claim 11,
Wherein the silicon carbide porous body has a porosity of 40% or more, an average pore size of 1 탆 to 50 탆, a 3-point bending strength of 45 MPa or more, and a volume resistivity of 10 ⁸ Ω · cm or more Gt;

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