WO2024070496A1 - Ceramic porous body and gas pipe - Google Patents

Ceramic porous body and gas pipe Download PDF

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WO2024070496A1
WO2024070496A1 PCT/JP2023/032052 JP2023032052W WO2024070496A1 WO 2024070496 A1 WO2024070496 A1 WO 2024070496A1 JP 2023032052 W JP2023032052 W JP 2023032052W WO 2024070496 A1 WO2024070496 A1 WO 2024070496A1
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porous body
ceramic porous
less
ceramic
gas
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PCT/JP2023/032052
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French (fr)
Japanese (ja)
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常夫 古宮山
浩臣 松葉
裕樹 臼杵
欣哉 各務
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日本碍子株式会社
エヌジーケイ・アドレック株式会社
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Publication of WO2024070496A1 publication Critical patent/WO2024070496A1/en

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  • Patent Document 1 discloses a gas pipe through which high-pressure gas (blow-by gas) passes.
  • Patent Document 1 lists rubber, synthetic resin, and metal as materials for the gas pipe.
  • gas piping is generally made of rubber, synthetic resin, metal, etc.
  • these materials are weak against deformation due to heat, and when the gas piping is used in a high-temperature environment, it is necessary to provide an insulating material on the outside of the gas piping to prevent deformation of the gas piping due to heat.
  • gas piping used in a high-temperature environment may be used to supply gas such as Ar gas to a high-temperature vacuum space. In this case, when a voltage is applied in the vacuum space, electrons are accelerated and discharge may occur.
  • the present specification aims to provide a ceramic porous body for realizing a gas piping in which the occurrence of discharge is suppressed.
  • the first technology disclosed in this specification is a ceramic porous body used in gas piping, in which the outer tube is filled with a ceramic porous body.
  • This ceramic porous body may have a porosity of 20% or more and 60% or less.
  • the second technology disclosed in this specification is a ceramic porous body according to the first technology, and may have a porosity of 30% or more and 45% or less.
  • the third technology disclosed in this specification is a ceramic porous body according to the second technology, and the porosity may be 30% or more and 40% or less.
  • the fourth technology disclosed in this specification is a ceramic porous body according to any one of the first to third technologies, in which the average particle size of the aggregate constituting the ceramic porous body may be 80 ⁇ m or more and 600 ⁇ m or less.
  • a fifth technology disclosed in this specification is a ceramic porous body according to any one of the first to third technologies, which may contain 5 to 20 mass % of SiO 2 and 80 to 95 mass % of Al 2 O 3 .
  • the sixth technology disclosed in this specification is the ceramic porous body of the fourth technology, which may contain 5 to 20 mass % of SiO 2 and 80 to 95 mass % of Al 2 O 3 .
  • the seventh technology disclosed in this specification is a ceramic porous body according to any one of the first to sixth technologies, in which the average particle size of the aggregate constituting the ceramic porous body may be 80 ⁇ m or more and 600 ⁇ m or less.
  • the eighth technology disclosed in this specification is the ceramic porous body of the seventh technology, in which the average particle size of the aggregate may be 100 ⁇ m or more and 500 ⁇ m or less.
  • a ninth technique disclosed in the present specification is a ceramic porous body according to any one of the first to eighth techniques, in which the amount of air permeation per minute when gas is passed through a gas pipe having an outer tube filled with the ceramic porous body is 420 ml/ cm2 or more and 1680 ml/ cm2 or less.
  • a tenth technology disclosed in this specification is the ceramic porous body of the ninth technology, in which the air permeability per minute may be 420 ml/ cm2 or more and 1050 ml/ cm2 or less.
  • the eleventh technology disclosed in this specification is a ceramic porous body according to any one of the first to tenth technologies, in which the main aggregate material constituting the ceramic porous body may be alumina, silica, silicon carbide, mullite, zirconia, or cordierite.
  • a twelfth technology disclosed in this specification is the ceramic porous body of the eleventh technology, wherein the ceramic porous body may contain at least one compound selected from Fe 2 O 3 , TiO 2 , CaO, MgO, and Na 2 O as a trace component.
  • the thirteenth technology disclosed in this specification is the ceramic porous body of the twelfth technology, in which the trace components may be contained in the following proportions: Fe 2 O 3 : 0.01-5%, CaO: 0.1-5%, MgO: 0.1-5%, and Na 2 O: 0.5-4%.
  • the 14th technology disclosed in this specification is a ceramic porous body according to the 11th to 13th technologies, in which the aggregate may be bonded with a glass bond.
  • the fifteenth technology disclosed in this specification is a gas pipe.
  • the ceramic porous body of the first to fourteenth technologies may be filled inside the outer tube.
  • the 16th technology disclosed in this specification is the gas piping of the 15th technology, in which the outer tube may be made of ceramics.
  • the 17th technology disclosed in this specification is a gas pipe according to the 15th or 16th technology, in which the porosity of the outer tube may be 5% or less.
  • 1 shows an SEM photograph of a radial cross section of a gas pipe in which an outer pipe is filled with a ceramic porous body.
  • 1 shows an SEM photograph of a longitudinal cross section of a gas pipe in which an outer pipe is filled with a ceramic porous body.
  • 1 shows an SEM photograph of a ceramic porous body.
  • the results of Experimental Example 1 are shown.
  • the results of Experimental Example 2 are shown.
  • the results of Experimental Example 3 are shown below.
  • the ceramic porous body disclosed in this specification is used as a material to fill a gas pipe. That is, the gas pipe includes an outer tube and a ceramic porous body filled in the outer tube.
  • the gas pipe is used, for example, to supply a gas such as Ar gas to a high-temperature vacuum space.
  • the gas to be supplied may be He, Ne, Kr, etc., in addition to Ar.
  • the material of the outer tube may be ceramics, metal, glass, resin, etc. If the outer tube is made of ceramics, there is an advantage that the outer tube and the ceramic porous body (particles constituting the ceramic porous body) can be integrated (sintered) by firing. If the outer tube (inner wall of the outer tube) and the ceramic porous body are sintered, damage to the ceramic porous body due to the pressure of the gas moving in the gas pipe can be suppressed.
  • alumina Al 2 O 3
  • silica SiO 2
  • silicon carbide SiC
  • mullite Al 6 O 13 Si 2
  • zirconia ZrO 2
  • cordierite 2MgO.2Al 2 O 3.5SiO 2
  • the "main aggregate” means the material (particle) that has the highest ratio in the mass of the ceramic porous body.
  • the ceramic porous body may have aggregates other than the main aggregate.
  • the above-mentioned alumina, silica, silicon carbide, mullite, zirconia, cordierite, etc. can be used.
  • the mass ratio of the main aggregate to the mass of the ceramic porous body may be 50 wt % or more. If the mass ratio of the main aggregate is 50 wt % or more, the strength of the ceramic porous body is sufficiently maintained, and the ceramic porous body can be suppressed from being broken.
  • the mass ratio of the main aggregate to the mass of the ceramic porous body may be 60 wt% or more, 70 wt% or more, or 80 wt% or more.
  • the mass ratio of the main aggregate to the mass of the ceramic porous body may be 95 wt% or less. If the mass ratio of the main aggregate is 95 wt% or less, there is sufficient room to add aggregate other than the main aggregate as a raw material for the ceramic porous body.
  • the mass ratio of the main aggregate to the mass of the ceramic porous body may be 90 wt% or less, or 85 wt% or less.
  • the ceramic porous body may contain at least one material selected from Fe 2 O 3 , TiO 2 , CaO, MgO, and Na 2 O as a trace component.
  • the trace component means a material whose proportion in the mass of the ceramic porous body is 5 wt% or less. By containing these trace components, the characteristics (heat resistance, strength, etc.) of the ceramic porous body can be adjusted according to the purpose.
  • the chemical composition of the ceramic porous body may be SiO 2 : 5-20%, Al 2 O 3 : 80-95%, Fe 2 O 3 : 0.01-5%, CaO: 0.1-5%, MgO: 0.1-5%, Na 2 O: 0.5-4%.
  • the aggregate may be bonded with a glass bond.
  • the glass bond may be the above-mentioned SiO 2 vitrified during firing.
  • the glass bond may also contain Al 2 O 3.
  • the mass ratio of SiO 2 to the mass of the glass bond may be 70 to 96 wt %, and the mass ratio of Al 2 O 3 may be 4 to 18 wt %.
  • the glass bond may contain the above-mentioned minor components. By containing minor components other than SiO 2 and Al 2 O 3 in the glass bond, the strength of the glass bond, the temperature at the time of vitrification, etc. can be adjusted .
  • the mass ratio of the glass bond to the mass of the ceramic porous body may be 5 wt % or more and 20 wt % or less.
  • the above gas piping can adjust the porosity of the outer tube (porous ceramic body) by adjusting the particle size of the ceramic particles that make up the porous ceramic body.
  • the porosity of the porous ceramic body may be 30% or more and 45% or less. If the porosity of the porous ceramic body is 30% or more, a gas flow path can be reliably secured in the outer tube.
  • the porosity of the porous ceramic body is 45% or less, for example, when a gas such as Ar gas is supplied to a high-temperature vacuum space, even if a voltage is applied to the vacuum space, a sufficient electron acceleration distance is secured in the outer tube, the acceleration of electrons is suppressed, and the occurrence of discharge can be suppressed.
  • the porosity of the porous ceramic body may be 35% or more, or may be 40% or more.
  • the porosity of the porous ceramic body may be 40% or less, or may be 35% or less.
  • the porosity of the outer tube may be smaller than that of the porous ceramic body, for example, 5% or less.
  • the amount of air per minute when gas is passed through the gas pipe may be 420 ml/cm 2 or more and 1680 ml/cm 2 or less. If the amount of air per minute is 420 ml/cm 2 or more, a sufficient gas flow path can be secured in the outer tube. If the amount of air per minute is 1680 ml/cm 2 or less, the electron acceleration distance is sufficiently suppressed, and the occurrence of discharge can be suppressed. Even if the porosity of the ceramic porous body is constant (for example, porosity of 30% or more and 45% or less), the amount of air permeation changes by adjusting the gas pressure.
  • the amount of air permeation per minute is 1680 ml/cm 2 or less.
  • the air permeability per minute may be 600 ml/ cm2 or more, 800 ml/ cm2 or more, or 1050 ml/ cm2 or more.
  • the air permeability per minute may be 1050 ml/ cm2 or less, 800 ml/ cm2 or less, or 600 ml/ cm2 or less.
  • the average particle diameter of the ceramic particles (aggregate) constituting the ceramic porous body may be 80 ⁇ m or more and 600 ⁇ m or less. If the average particle diameter of the ceramic particles is 80 ⁇ m or more, gaps are secured between the particles, and a gas flow path can be reliably secured. In addition, if the average particle diameter of the ceramic particles is 80 ⁇ m or more, the manufacturing yield (firing yield) of the gas pipe can be improved. If the average particle diameter of the ceramic particles is 600 ⁇ m or less, the contact area between the ceramic particles and the inner wall of the outer tube increases, and the two can be stably bonded.
  • the average particle diameter of the ceramic particles is 600 ⁇ m or less, the moldability of the gas pipe (the ability to fill the ceramic porous body into the outer tube) can be improved.
  • the average particle diameter of the ceramic particles may be 100 ⁇ m or more, 150 ⁇ m or more, 200 ⁇ m or more, 300 ⁇ m or more, 400 ⁇ m or more, or 500 ⁇ m or more.
  • the average particle size of the ceramic particles may be 500 ⁇ m or less, 400 ⁇ m or less, 300 ⁇ m or less, 200 ⁇ m or less, 150 ⁇ m or less, or 100 ⁇ m or less.
  • the average distance between the ceramic particles (average pore size) may be 10 ⁇ m or more and 200 ⁇ m or less.
  • the gas pipe has a solid structure from a macroscopic perspective, since the inside of the outer tube is filled with a porous ceramic body. Therefore, even if the outer tube is made of ceramic, it has the advantage that it is less likely to crack due to physical or thermal shock, compared to a hollow structure in which the inside of the outer tube is not filled with a porous ceramic body.
  • Figure 1 shows a radial cross section of the gas pipe 10
  • Figure 2 shows a longitudinal cross section of the gas pipe 10.
  • a ceramic porous body 5 is provided inside the outer pipe 2.
  • the ceramic porous body 5 is formed by filling the outer pipe 2 with a plurality of particles 4. It can be seen that there are voids 6 between the particles 4, 4. The voids 6 are provided and dispersed throughout the outer pipe 2.
  • the material of the outer tube 2 is alumina, the thickness is 10 mm, and the porosity is 5%.
  • the ceramic porous body 5 is formed by firing alumina coarse particles, alumina fine particles, and glass.
  • the average particle size of the particles 4 is 100 to 500 ⁇ m, and forms the aggregate of the ceramic porous body 5.
  • the porosity of the porous portion 5 is 30%.
  • the chemical composition of the ceramic porous body 5 is SiO 2 : 12%, Al 2 O 3 : 91%, Fe 2 O 3 : 0.08%, CaO: 0.29%, MgO: 0.30%, Na 2 O: 0.95%.
  • the gas pipe 10 was produced by forming an outer tube 2 by extrusion molding, and then forming a ceramic porous body 5 inside the outer tube 2. Specifically, a mixture of alumina and binder was first formed into a shape with an outer diameter of ⁇ 30 mm and an inner diameter of ⁇ 10 mm using an extrusion molding machine, and dried at 60°C. It was then fired in an air atmosphere at 1300-1600°C for 5 hours.
  • a mixture of alumina, silica, and binder was prepared and filled into the fired outer tube, and fired in an air atmosphere at 1100-1300°C for 4 hours.
  • the firing sintered the alumina particles to form a ceramic porous body 5, and also sintered the inner wall of the outer tube 2 and the ceramic porous body 5, resulting in a gas pipe 10 in which the outer tube 2 and the ceramic porous body 5 are integrated.
  • Figure 3 shows a cross-sectional view of a ceramic porous body 5. As shown in Figure 3, particles (alumina particles) 4 are bonded together with glass bonds 6. The glass bonds 6 are formed when silica is vitrified during firing.
  • Example 1 Alumina particles having an average particle size of 300 ⁇ m were used, and the blending amount and firing conditions were changed to produce a plurality of gas pipes 10 (samples 1 to 9) having different porosities of the ceramic porous body 5.
  • the gas pipes 10 thus obtained were subjected to measurement of the air permeability and an Ar gas flow test. The measurement of the air permeability was performed using a 30 mm gas pipe 10, and the Ar gas flow test was performed using a 100 mm gas pipe 10. The results are shown in FIG. 4.
  • the porosity was measured by the Archimedes method.
  • the amount of airflow was measured by passing Ar gas through the gas pipe 10 while increasing the flow rate, and measuring the gas flow rate per minute (ml/cm 2 /min) when the pressure loss reached 0.49 kPa.
  • Samples with an airflow rate of 400 (ml/cm 2 /min) or more were classified as "A”
  • samples with an airflow rate of 200 (ml/cm 2 /min) or more and less than 400 (ml/cm 2 /min) were classified as "B”
  • samples with an airflow rate of less than 200 (ml/cm 2 /min) were classified as "C”. If the amount of airflow is 200 (ml/cm 2 /min) or more, it can be evaluated that a sufficient gas flow path is secured as a gas pipe.
  • samples with a porosity of 30% or more obtained an amount of air permeation of 400 (ml/cm 2 /min) or more (evaluation "A"), and it was confirmed that a good amount of air permeation was obtained as a gas pipe.
  • samples with a porosity of 45% or less obtained the results of the Ar gas flow test as "A” or "B", and it was confirmed that the occurrence of discharge was suppressed.
  • samples with a porosity of 40% or less did not generate discharge and obtained good results.
  • the porosity of the gas pipe is 30% or more and 45% or less, a gas pipe with excellent air permeability and suppressed occurrence of discharge can be obtained.
  • Example 2 Alumina particles (aggregates) with different average particle sizes were prepared, and the blending amounts and firing conditions were changed to produce gas pipes 10 (samples 11 to 23) with a porosity of the ceramic porous body 5 of 35%. Samples 11 to 22 were evaluated for moldability and firing yield of the gas pipes 10. The results are shown in FIG.
  • samples with an average particle size of alumina particles of 600 ⁇ m or less had good moldability, and that the raw material of the ceramic porous body 5 could be reliably filled into the outer tube 2.
  • samples with an average particle size of alumina particles of 80 ⁇ m or more had a sintering yield result of "A" or "B”, and that the alumina particles were sufficiently bonded with glass bonds.
  • samples with an average particle size of alumina particles of 100 ⁇ m or more and 500 ⁇ m or less were confirmed to have particularly good sintering yields, with 80% or more of the alumina particles bonded with glass bonds.
  • gas piping can be stably manufactured if the average particle size of the alumina particles (aggregate) is 50 ⁇ m or more and 600 ⁇ m or less.
  • Example 3 Gas pipes 10 (samples 31 to 40) having different gas permeabilities were fabricated using alumina particles (aggregates) with different average particle sizes and a ceramic porous body 5 with a porosity of 30%. Samples 31 to 40 were subjected to an Ar gas flow test similar to that of Experimental Example 1. The results of the Ar gas flow test are shown in FIG. 6.

Abstract

This ceramic porous body is used in a gas pipe in which a ceramic porous body is filled in an outer pipe. The ceramic porous body has a porosity of 20% to 60% inclusive.

Description

セラミックス多孔体及びガス配管Porous ceramics and gas piping
　本出願は、２０２２年９月２９日に出願された日本国特許出願第２０２２－１５６１７９号に基づく優先権を主張する。その出願の全ての内容は、この明細書中に参照により援用されている。本明細書は、セラミックス多孔体及びガス配管に関する技術を開示する。 This application claims priority to Japanese Patent Application No. 2022-156179, filed on September 29, 2022, the entire contents of which are incorporated herein by reference. This specification discloses technology relating to ceramic porous bodies and gas piping.
　特開２０１６－１３５９９６号公報（以下、特許文献１と称する）に、高圧ガス（ブローバイガス）が通過するガス配管が開示されている。特許文献１には、ガス配管の材料としてラバー、合成樹脂、金属が挙げられている。 　Japanese Patent Publication No. 2016-135996 (hereinafter referred to as Patent Document 1) discloses a gas pipe through which high-pressure gas (blow-by gas) passes. Patent Document 1 lists rubber, synthetic resin, and metal as materials for the gas pipe.
　特許文献１に開示されているように、一般的に、ガス配管はラバー、合成樹脂、金属等で形成されている。しかしながら、これらの材料は熱による変形等に弱く、ガス配管を高温環境下で使用する場合、熱によるガス配管の変形等を防止するため、ガス配管の外部に断熱材を設けることが必要となる。例えば、ガス配管の材料としてセラミックスを利用すると、高温環境下で用いる場合であっても、ガス配管の外部に断熱材を設ける必要はない。高温環境下で用いられるガス配管は、高温の真空空間にＡｒガス等の気体を供給する用途で用いられることがある。この場合、真空空間で電圧が印加されると、電子が加速し、放電が発生することが起こり得る。放電の発生を抑制するためには、外管内にセラミックス多孔体を充填し、外管内の電子加速距離を制御することが必要である。本明細書は、放電の発生が抑制されたガス配管を実現するためのセラミックス多孔体を提供することを目的とする。 As disclosed in Patent Document 1, gas piping is generally made of rubber, synthetic resin, metal, etc. However, these materials are weak against deformation due to heat, and when the gas piping is used in a high-temperature environment, it is necessary to provide an insulating material on the outside of the gas piping to prevent deformation of the gas piping due to heat. For example, when ceramics is used as the material of the gas piping, it is not necessary to provide an insulating material on the outside of the gas piping even when it is used in a high-temperature environment. Gas piping used in a high-temperature environment may be used to supply gas such as Ar gas to a high-temperature vacuum space. In this case, when a voltage is applied in the vacuum space, electrons are accelerated and discharge may occur. In order to suppress the occurrence of discharge, it is necessary to fill the outer tube with a ceramic porous body and control the electron acceleration distance in the outer tube. The present specification aims to provide a ceramic porous body for realizing a gas piping in which the occurrence of discharge is suppressed.
　本明細書で開示する第１技術は、外管内にセラミックス多孔体が充填されているガス配管で用いられるセラミックス多孔体である。このセラミックス多孔体は、気孔率が２０％以上６０％以下であってよい。 The first technology disclosed in this specification is a ceramic porous body used in gas piping, in which the outer tube is filled with a ceramic porous body. This ceramic porous body may have a porosity of 20% or more and 60% or less.
　本明細書で開示する第２技術は、上記第１技術のセラミックス多孔体であって、気孔率が３０％以上４５％以下であってよい。 The second technology disclosed in this specification is a ceramic porous body according to the first technology, and may have a porosity of 30% or more and 45% or less.
　本明細書で開示する第３技術は、上記第２技術のセラミックス多孔体であって、気孔率が３０％以上４０％以下であってよい。 The third technology disclosed in this specification is a ceramic porous body according to the second technology, and the porosity may be 30% or more and 40% or less.
　本明細書で開示する第４技術は、上記第１から第３技術のいずれかのセラミックス多孔体であって、セラミックス多孔体を構成している骨材の平均粒子径が、８０μｍ以上６００μｍ以下であってよい。 The fourth technology disclosed in this specification is a ceramic porous body according to any one of the first to third technologies, in which the average particle size of the aggregate constituting the ceramic porous body may be 80 μm or more and 600 μm or less.
　本明細書で開示する第５技術は、上記第１から第３技術のいずれかのセラミックス多孔体であって、ＳｉＯ２を５～２０質量％、Ａｌ２Ｏ３を８０～９５質量％含んでいてよい。 A fifth technology disclosed in this specification is a ceramic porous body according to any one of the first to third technologies, which may contain 5 to 20 mass % of SiO 2 and 80 to 95 mass % of Al 2 O 3 .
　本明細書で開示する第６技術は、上記第４技術のセラミックス多孔体であって、ＳｉＯ２を５～２０質量％、Ａｌ２Ｏ３を８０～９５質量％含んでいてよい。 The sixth technology disclosed in this specification is the ceramic porous body of the fourth technology, which may contain 5 to 20 mass % of SiO 2 and 80 to 95 mass % of Al 2 O 3 .
　本明細書で開示する第７技術は、上記第１から第６技術のいずれかのセラミックス多孔体であって、セラミックス多孔体を構成している骨材の平均粒子径が、８０μｍ以上６００μｍ以下であってよい。 The seventh technology disclosed in this specification is a ceramic porous body according to any one of the first to sixth technologies, in which the average particle size of the aggregate constituting the ceramic porous body may be 80 μm or more and 600 μm or less.
　本明細書で開示する第８技術は、上記第７技術のセラミックス多孔体であって、骨材の平均粒子径が、１００μｍ以上５００μｍ以下であってよい。 The eighth technology disclosed in this specification is the ceramic porous body of the seventh technology, in which the average particle size of the aggregate may be 100 μm or more and 500 μm or less.
　本明細書で開示する第９技術は、上記第１から第８技術のいずれかのセラミックス多孔体であって、セラミックス多孔体を外管に充填したガス配管にガスを流通させたときの１分当たりの通気量が、４２０ｍｌ／ｃｍ２以上１６８０ｍｌ／ｃｍ２以下であってよい。 A ninth technique disclosed in the present specification is a ceramic porous body according to any one of the first to eighth techniques, in which the amount of air permeation per minute when gas is passed through a gas pipe having an outer tube filled with the ceramic porous body is 420 ml/ cm2 or more and 1680 ml/ cm2 or less.
　本明細書で開示する第１０技術は、上記第９技術のセラミックス多孔体であって、１分当たりの通気量が、４２０ｍｌ／ｃｍ２以上１０５０ｍｌ／ｃｍ２以下であってよい。 A tenth technology disclosed in this specification is the ceramic porous body of the ninth technology, in which the air permeability per minute may be 420 ml/ cm2 or more and 1050 ml/ cm2 or less.
　本明細書で開示する第１１技術は、上記第１から第１０技術のいずれかのセラミックス多孔体であって、セラミックス多孔体を構成している主骨材の材料が、アルミナ、シリカ、炭化ケイ素、ムライト、ジルコニア又はコージェライトであってよい。 The eleventh technology disclosed in this specification is a ceramic porous body according to any one of the first to tenth technologies, in which the main aggregate material constituting the ceramic porous body may be alumina, silica, silicon carbide, mullite, zirconia, or cordierite.
　本明細書で開示する第１２技術は、上記第１１技術のセラミックス多孔体であって、セラミックス多孔体が、Ｆｅ２Ｏ３、ＴｉＯ２、ＣａＯ、ＭｇＯ、Ｎａ２Ｏから選択される化合物の少なくとも１つを微量成分として含んでいてよい。 A twelfth technology disclosed in this specification is the ceramic porous body of the eleventh technology, wherein the ceramic porous body may contain at least one compound selected from Fe 2 O 3 , TiO 2 , CaO, MgO, and Na 2 O as a trace component.
　本明細書で開示する第１３技術は、上記第１２技術のセラミックス多孔体であって、上記微量成分が、Ｆｅ２Ｏ３：０．０１～５％、ＣａＯ：０．１～５％、ＭｇＯ：０．１～５％、Ｎａ２Ｏ：０．５～４％の割合で含まれていてよい。 The thirteenth technology disclosed in this specification is the ceramic porous body of the twelfth technology, in which the trace components may be contained in the following proportions: Fe 2 O 3 : 0.01-5%, CaO: 0.1-5%, MgO: 0.1-5%, and Na 2 O: 0.5-4%.
　本明細書で開示する第１４技術は、上記第１１から第１３技術のセラミックス多孔体であって、上記骨材がガラスボンドで結合されていてよい。 The 14th technology disclosed in this specification is a ceramic porous body according to the 11th to 13th technologies, in which the aggregate may be bonded with a glass bond.
　本明細書で開示する第１５技術は、ガス配管である。このガス配管は、上記第１から第１４技術のセラミックス多孔体が、上記外管内に充填されていてよい。 The fifteenth technology disclosed in this specification is a gas pipe. In this gas pipe, the ceramic porous body of the first to fourteenth technologies may be filled inside the outer tube.
　本明細書で開示する第１６技術は、上記第１５技術のガス配管であって、上記外管がセラミックス製であってよい。 The 16th technology disclosed in this specification is the gas piping of the 15th technology, in which the outer tube may be made of ceramics.
　本明細書で開示する第１７技術は、上記第１５または第１６技術のガス配管であって、上記外管の気孔率が５％以下であってよい。 The 17th technology disclosed in this specification is a gas pipe according to the 15th or 16th technology, in which the porosity of the outer tube may be 5% or less.
外管内にセラミックス多孔体が充填されたガス配管の径方向断面のＳＥＭ写真を示す。1 shows an SEM photograph of a radial cross section of a gas pipe in which an outer pipe is filled with a ceramic porous body. 外管内にセラミックス多孔体が充填されたガス配管の長手方向断面のＳＥＭ写真を示す。1 shows an SEM photograph of a longitudinal cross section of a gas pipe in which an outer pipe is filled with a ceramic porous body. セラミックス多孔体のＳＥＭ写真を示す。1 shows an SEM photograph of a ceramic porous body. 実験例１の結果を示す。The results of Experimental Example 1 are shown. 実験例２の結果を示す。The results of Experimental Example 2 are shown. 実験例３の結果を示す。The results of Experimental Example 3 are shown below.
　本明細書で開示するセラミックス多孔体は、ガス配管内を充填する材料として用いられる。すなわち、ガス配管は、外管と、外管内に充填されているセラミックス多孔体を備えている。ガス配管は、例えば、高温の真空空間にＡｒガス等の気体を供給する用途で用いられる。例えば、供給する気体は、Ａｒの他に、Ｈｅ、Ｎｅ、Ｋｒ等であってもよい。外管の材料は、セラミックス、金属、ガラス、樹脂等を用いることができる。なお、外管がセラミックス製であれば、外管とセラミックス多孔体（セラミックス多孔体を構成している粒子）を、焼成を行うことによって一体化（焼結）することができるという利点が得られる。外管（外管の内壁）とセラミックス多孔体が焼結していると、ガス配管内を移動するガスの圧力に起因してセラミックス多孔体が破損することを抑制できる。 The ceramic porous body disclosed in this specification is used as a material to fill a gas pipe. That is, the gas pipe includes an outer tube and a ceramic porous body filled in the outer tube. The gas pipe is used, for example, to supply a gas such as Ar gas to a high-temperature vacuum space. For example, the gas to be supplied may be He, Ne, Kr, etc., in addition to Ar. The material of the outer tube may be ceramics, metal, glass, resin, etc. If the outer tube is made of ceramics, there is an advantage that the outer tube and the ceramic porous body (particles constituting the ceramic porous body) can be integrated (sintered) by firing. If the outer tube (inner wall of the outer tube) and the ceramic porous body are sintered, damage to the ceramic porous body due to the pressure of the gas moving in the gas pipe can be suppressed.
　セラミックス多孔体の主骨材の材料として、アルミナ（Ａｌ２Ｏ３）、シリカ（ＳｉＯ２）、炭化ケイ素（ＳｉＣ）、ムライト（Ａｌ６Ｏ１３Ｓｉ２）、ジルコニア（ＺｒＯ2）、コージェライト（２ＭｇＯ・２Ａｌ２Ｏ３・５ＳｉＯ２）等を用いることができる。なお、「主骨材」とは、セラミックス多孔体の質量に占める割合が最も高い材料（粒子）のことを意味する。セラミックス多孔体は、主骨材の他にも骨材を有していてもよい。主骨材以外の骨材として、上述したアルミナ、シリカ、炭化ケイ素、ムライト、ジルコニア、コージェライト等を用いることができる。セラミックス多孔体の質量に占める主骨材の質量割合は、５０ｗｔ％以上であってよい。主骨材の質量割合が５０ｗｔ％以上であれば、セラミックス多孔体の強度が十分に維持され、セラミックス多孔体が破損することを抑制することができる。なお、セラミックス多孔体の質量に占める主骨材の質量割合は、６０ｗｔ％以上であってよく、７０ｗｔ％以上であってよく、８０ｗｔ％以上であってもよい。また、セラミックス多孔体の質量に占める主骨材の質量割合は、９５ｗｔ％以下であってよい。主骨材の質量割合が９５ｗｔ％以下であれば、セラミックス多孔体の原料として主骨材以外の骨材を添加する余地を十分に確保することができる。セラミックス多孔体の質量に占める主骨材の質量割合は、９０ｗｔ％以下であってよく、８５ｗｔ％以下であってもよい。 As the material of the main aggregate of the ceramic porous body, alumina (Al 2 O 3 ), silica (SiO 2 ), silicon carbide (SiC), mullite (Al 6 O 13 Si 2 ), zirconia (ZrO 2 ), cordierite (2MgO.2Al 2 O 3.5SiO 2 ), etc. can be used. In addition, the "main aggregate" means the material (particle) that has the highest ratio in the mass of the ceramic porous body. The ceramic porous body may have aggregates other than the main aggregate. As the aggregate other than the main aggregate, the above-mentioned alumina, silica, silicon carbide, mullite, zirconia, cordierite, etc. can be used. The mass ratio of the main aggregate to the mass of the ceramic porous body may be 50 wt % or more. If the mass ratio of the main aggregate is 50 wt % or more, the strength of the ceramic porous body is sufficiently maintained, and the ceramic porous body can be suppressed from being broken. The mass ratio of the main aggregate to the mass of the ceramic porous body may be 60 wt% or more, 70 wt% or more, or 80 wt% or more. The mass ratio of the main aggregate to the mass of the ceramic porous body may be 95 wt% or less. If the mass ratio of the main aggregate is 95 wt% or less, there is sufficient room to add aggregate other than the main aggregate as a raw material for the ceramic porous body. The mass ratio of the main aggregate to the mass of the ceramic porous body may be 90 wt% or less, or 85 wt% or less.
　セラミックス多孔体は、微量成分として、Ｆｅ２Ｏ３、ＴｉＯ２、ＣａＯ、ＭｇＯ、Ｎａ２Ｏから選択される化合物の少なくとも１つの材料を含んでいてもよい。なお、微量成分とは、セラミックス多孔体の質量に占める割合が５ｗｔ％以下の材料のことを意味する。これらの微量成分を含むことにより、セラミックス多孔体の特性（耐熱性、強度等）を目的に合わせて調整することができる。一例として、セラミックス多孔体の化学組成は、ＳｉＯ２：５～２０％，Ａｌ２Ｏ３：８０～９５％，Ｆｅ２Ｏ３：０．０１～５％，ＣａＯ：０．１～５％，ＭｇＯ：０．１～５％，Ｎａ２Ｏ：０．５～４％であってよい。 The ceramic porous body may contain at least one material selected from Fe 2 O 3 , TiO 2 , CaO, MgO, and Na 2 O as a trace component. The trace component means a material whose proportion in the mass of the ceramic porous body is 5 wt% or less. By containing these trace components, the characteristics (heat resistance, strength, etc.) of the ceramic porous body can be adjusted according to the purpose. As an example, the chemical composition of the ceramic porous body may be SiO 2 : 5-20%, Al 2 O 3 : 80-95%, Fe 2 O 3 : 0.01-5%, CaO: 0.1-5%, MgO: 0.1-5%, Na 2 O: 0.5-4%.
　上記骨材は、ガラスボンドで結合されていてよい。ガラスボンドで骨材同士を結合することにより、骨材間が強固に結合され、セラミックス多孔体の強度を向上させることができる。なお、ガラスボンドは、上述したＳｉＯ２が焼成の際にガラス化したものであってよい。また、ガラスボンドは、Ａｌ２Ｏ３を含んでいてよい。一例として、ガラスボンドの質量に占めるＳｉＯ２の質量割合は７０～９６ｗｔ％であり、Ａｌ２Ｏ３の質量割合は４～１８ｗｔ％であってよい。さらに、ガラスボンドは、上述した微量成分を含んでいてよい。ガラスボンドにＳｉＯ２、Ａｌ２Ｏ３以外の微量成分が含まれることにより、ガラスボンドの強度、ガラス化する際の温度等を調整することができる。なお、セラミックス多孔体の質量に占めるガラスボンドの質量割合は５ｗｔ％以上２０ｗｔ％以下であってよい。 The aggregate may be bonded with a glass bond. By bonding the aggregates with the glass bond, the aggregates are firmly bonded to each other, and the strength of the ceramic porous body can be improved. The glass bond may be the above-mentioned SiO 2 vitrified during firing. The glass bond may also contain Al 2 O 3. As an example, the mass ratio of SiO 2 to the mass of the glass bond may be 70 to 96 wt %, and the mass ratio of Al 2 O 3 may be 4 to 18 wt %. Furthermore, the glass bond may contain the above-mentioned minor components. By containing minor components other than SiO 2 and Al 2 O 3 in the glass bond, the strength of the glass bond, the temperature at the time of vitrification, etc. can be adjusted . The mass ratio of the glass bond to the mass of the ceramic porous body may be 5 wt % or more and 20 wt % or less.
　上記ガス配管は、セラミックス多孔体を構成するセラミックス粒子の粒径等を調整することにより、外管内（セラミックス多孔体）の気孔率を調整することができる。セラミックス多孔体の気孔率を調整することにより、外管内の電子加速距離を制御することができる。セラミックス多孔体の気孔率は、３０％以上４５％以下であってよい。セラミックス多孔体の気孔率が３０％以上であれば、外管内に確実にガス流路を確保することができる。また、セラミックス多孔体の気孔率が４５％以下であれば、例えば高温の真空空間にＡｒガス等の気体を供給する際、真空空間に電圧が印加されても、外管内に十分な電子加速距離が確保され、電子の加速が抑制され、放電の発生を抑制することができる。セラミックス多孔体の気孔率は、３５％以上であってよく、４０％以上であってもよい。また、セラミックス多孔体の気孔率は、４０％以下であってよく、３５％以下であってもよい。なお、外管の気孔率は、セラミックス多孔体より小さく、例えば５％以下であってよい。外管の気孔率を５％以下に調整することにより、ガス配管内のガスが外管を通過してガス配管外に漏れることを防止することができる。 The above gas piping can adjust the porosity of the outer tube (porous ceramic body) by adjusting the particle size of the ceramic particles that make up the porous ceramic body. By adjusting the porosity of the porous ceramic body, the electron acceleration distance in the outer tube can be controlled. The porosity of the porous ceramic body may be 30% or more and 45% or less. If the porosity of the porous ceramic body is 30% or more, a gas flow path can be reliably secured in the outer tube. Furthermore, if the porosity of the porous ceramic body is 45% or less, for example, when a gas such as Ar gas is supplied to a high-temperature vacuum space, even if a voltage is applied to the vacuum space, a sufficient electron acceleration distance is secured in the outer tube, the acceleration of electrons is suppressed, and the occurrence of discharge can be suppressed. The porosity of the porous ceramic body may be 35% or more, or may be 40% or more. Furthermore, the porosity of the porous ceramic body may be 40% or less, or may be 35% or less. The porosity of the outer tube may be smaller than that of the porous ceramic body, for example, 5% or less. By adjusting the porosity of the outer tube to 5% or less, it is possible to prevent gas in the gas pipe from passing through the outer tube and leaking out of the gas pipe.
　セラミックス多孔体が外管に充填されたガス配管において、ガス配管にガスを流通させたときの１分当たりの通気量は、４２０ｍｌ／ｃｍ２以上１６８０ｍｌ／ｃｍ２以下であってよい。１分当たりの通気量が４２０ｍｌ／ｃｍ２以上であれば、外管内に十分なガス流路を確保することができる。また、１分当たりの通気量が１６８０ｍｌ／ｃｍ２以下であれば、電子加速距離が十分に抑制され、放電の発生を抑制することができる。なお、セラミックス多孔体の気孔率が一定（例えば、気孔率３０％以上４５％以下）であっても、ガス圧を調整することにより、通気量は変化する。すなわち、セラミックス多孔体の気孔率が同一であっても、ガス圧を高くすると、通気量が上昇する。しかしながら、ガス圧が高くなりすぎると、外管又はセラミックス多孔体が破損しやすくなる。そのため、ガス配管の破損を抑制するという観点からも、１分当たりの通気量は１６８０ｍｌ／ｃｍ２以下であることが好ましい。なお、１分当たりの通気量は、６００ｍｌ／ｃｍ２以上であってよく、８００ｍｌ／ｃｍ２以上であってよく、１０５０ｍｌ／ｃｍ２以上であってもよい。また、１分当たりの通気量は、１０５０ｍｌ／ｃｍ２以下であってよく、８００ｍｌ／ｃｍ２以下であってよく、６００ｍｌ／ｃｍ２以下であってもよい。 In a gas pipe in which a ceramic porous body is filled in an outer tube, the amount of air per minute when gas is passed through the gas pipe may be 420 ml/cm 2 or more and 1680 ml/cm 2 or less. If the amount of air per minute is 420 ml/cm 2 or more, a sufficient gas flow path can be secured in the outer tube. If the amount of air per minute is 1680 ml/cm 2 or less, the electron acceleration distance is sufficiently suppressed, and the occurrence of discharge can be suppressed. Even if the porosity of the ceramic porous body is constant (for example, porosity of 30% or more and 45% or less), the amount of air permeation changes by adjusting the gas pressure. That is, even if the porosity of the ceramic porous body is the same, the amount of air permeation increases when the gas pressure is increased. However, if the gas pressure becomes too high, the outer tube or the ceramic porous body becomes easily damaged. Therefore, from the viewpoint of suppressing damage to the gas pipe, it is preferable that the amount of air permeation per minute is 1680 ml/cm 2 or less. The air permeability per minute may be 600 ml/ cm2 or more, 800 ml/ cm2 or more, or 1050 ml/ cm2 or more. The air permeability per minute may be 1050 ml/ cm2 or less, 800 ml/ cm2 or less, or 600 ml/ cm2 or less.
　セラミックス多孔体を構成するセラミックス粒子（骨材）の平均粒子径は、８０μｍ以上６００μｍ以下であってよい。セラミックス粒子の平均粒子径が８０μｍ以上であれば、粒子間に隙間が確保され、ガス流路を確実に確保することができる。また、セラミックス粒子の平均粒子径が８０μｍ以上であれば、ガス配管の製造歩留（焼成歩留）を向上させることができる。セラミックス粒子の平均粒子径が６００μｍ以下であれば、セラミックス粒子同士の接触面積、及び、セラミックス粒子と外管の内壁の接触面積が増大し、両者を安定して結合させることができる。また、セラミックス粒子の平均粒子径が６００μｍ以下であれば、ガス配管の成形性（セラミックス多孔体の外管への充填性）を向上させることができる。セラミックス粒子の平均粒子径は、１００μｍ以上であってよく、１５０μｍ以上であってよく、２００μｍ以上であってよく、３００μｍ以上であってよく、４００μｍ以上であってよく、５００μｍ以上であってもよい。また、セラミックス粒子の平均粒子径は、５００μｍ以下であってよく、４００μｍ以下であってよく、３００μｍ以下であってよく、２００μｍ以下であってよく、１５０μｍ以下であってよく、１００μｍ以下であってもよい。なお、セラミックス粒子間の平均距離（平均気孔径）は、１０μｍ以上２００μｍ以下であってよい。 The average particle diameter of the ceramic particles (aggregate) constituting the ceramic porous body may be 80 μm or more and 600 μm or less. If the average particle diameter of the ceramic particles is 80 μm or more, gaps are secured between the particles, and a gas flow path can be reliably secured. In addition, if the average particle diameter of the ceramic particles is 80 μm or more, the manufacturing yield (firing yield) of the gas pipe can be improved. If the average particle diameter of the ceramic particles is 600 μm or less, the contact area between the ceramic particles and the inner wall of the outer tube increases, and the two can be stably bonded. In addition, if the average particle diameter of the ceramic particles is 600 μm or less, the moldability of the gas pipe (the ability to fill the ceramic porous body into the outer tube) can be improved. The average particle diameter of the ceramic particles may be 100 μm or more, 150 μm or more, 200 μm or more, 300 μm or more, 400 μm or more, or 500 μm or more. The average particle size of the ceramic particles may be 500 μm or less, 400 μm or less, 300 μm or less, 200 μm or less, 150 μm or less, or 100 μm or less. The average distance between the ceramic particles (average pore size) may be 10 μm or more and 200 μm or less.
　なお、上記ガス配管は、外管の内部をセラミックス多孔体が充填しているので、マクロ的にみると中実構造である。そのため、外管の材料がセラミックス製であっても、外管の内部にセラミックス多孔体が充填されていない中空構造の形態と比較して、物理的・熱的衝撃による「割れ」が生じにくいという利点も得られる。 The gas pipe has a solid structure from a macroscopic perspective, since the inside of the outer tube is filled with a porous ceramic body. Therefore, even if the outer tube is made of ceramic, it has the advantage that it is less likely to crack due to physical or thermal shock, compared to a hollow structure in which the inside of the outer tube is not filled with a porous ceramic body.
　図１から図３を参照し、ガス配管１０について説明する。図１はガス配管１０の径方向断面を示し、図２はガス配管１０の長手方向断面を示している。図１、２に示すように、外管２の内側に、セラミックス多孔体５が設けられている。セラミックス多孔体５は、複数の粒子４を外管２内に充填することにより形成されている。粒子４，４間には空隙６が存在することが確認される。空隙６は、外管２内の全体に分散して設けられている。 The gas pipe 10 will be described with reference to Figures 1 to 3. Figure 1 shows a radial cross section of the gas pipe 10, and Figure 2 shows a longitudinal cross section of the gas pipe 10. As shown in Figures 1 and 2, a ceramic porous body 5 is provided inside the outer pipe 2. The ceramic porous body 5 is formed by filling the outer pipe 2 with a plurality of particles 4. It can be seen that there are voids 6 between the particles 4, 4. The voids 6 are provided and dispersed throughout the outer pipe 2.
　外管２の材料はアルミナであり、厚みは１０ｍｍであり、気孔率は５％である。また、セラミックス多孔体５は、アルミナ粗粒とアルミナ微粒とガラスを焼成することにより形成されている。粒子４の平均粒子径は１００～５００μｍであり、セラミックス多孔体５の骨材を形成している。多孔質部５の気孔率は３０％である。なお、セラミックス多孔体５の化学組成は、ＳｉＯ２：１２％，Ａｌ２Ｏ３：９１％，Ｆｅ２Ｏ３：０．０８％，ＣａＯ：０．２９％，ＭｇＯ：０．３０％，Ｎａ２Ｏ：０．９５％である。 The material of the outer tube 2 is alumina, the thickness is 10 mm, and the porosity is 5%. The ceramic porous body 5 is formed by firing alumina coarse particles, alumina fine particles, and glass. The average particle size of the particles 4 is 100 to 500 μm, and forms the aggregate of the ceramic porous body 5. The porosity of the porous portion 5 is 30%. The chemical composition of the ceramic porous body 5 is SiO 2 : 12%, Al 2 O 3 : 91%, Fe 2 O 3 : 0.08%, CaO: 0.29%, MgO: 0.30%, Na 2 O: 0.95%.
　ガス配管１０は、押出成形により外管２を形成した後、外管２内にセラミックス多孔体５を形成して作製した。具体的には、まず、アルミナとバインダーの混合物を押出成形機を用いて外径φ３０ｍｍ、内径φ１０ｍｍに形成し、６０℃で乾燥させた。その後、大気雰囲気にて１３００～１６００℃で５時間焼成した。 The gas pipe 10 was produced by forming an outer tube 2 by extrusion molding, and then forming a ceramic porous body 5 inside the outer tube 2. Specifically, a mixture of alumina and binder was first formed into a shape with an outer diameter of φ30 mm and an inner diameter of φ10 mm using an extrusion molding machine, and dried at 60°C. It was then fired in an air atmosphere at 1300-1600°C for 5 hours.
　次に、アルミナとシリカとバインダーの混合物を用意し、焼成後の外管内に充填し、大気雰囲気にて１１００～１３００℃で４時間焼成した。焼成により、アルミナ粒子が焼結してセラミックス多孔体５が形成されるとともに、外管２の内壁とセラミックス多孔体５が焼結し、外管２とセラミックス多孔体５が一体化されたガス配管１０が得られた。 Next, a mixture of alumina, silica, and binder was prepared and filled into the fired outer tube, and fired in an air atmosphere at 1100-1300°C for 4 hours. The firing sintered the alumina particles to form a ceramic porous body 5, and also sintered the inner wall of the outer tube 2 and the ceramic porous body 5, resulting in a gas pipe 10 in which the outer tube 2 and the ceramic porous body 5 are integrated.
　図３は、セラミックス多孔体５の断面図を示している。図３に示すように、粒子（アルミナ粒子）４同士はガラスボンド６で結合されている。ガラスボンド６は、焼成の際にシリカがガラス化したものである。 Figure 3 shows a cross-sectional view of a ceramic porous body 5. As shown in Figure 3, particles (alumina particles) 4 are bonded together with glass bonds 6. The glass bonds 6 are formed when silica is vitrified during firing.
（実験例１）
　平均粒子径３００μｍのアルミナ粒子を利用し、配合量及び焼成条件を変化させ、セラミックス多孔体５の気孔率の異なる複数のガス配管１０（試料１～９）を作製した。得られたガス配管１０について、通気量の測定及びＡｒガス流通試験を行った。なお、通気量の測定は３０ｍｍのガス配管１０を用い、Ａｒガス流通試験は１００ｍｍのガス配管１０を用いて行った。結果を図４に示す。 (Experimental Example 1)
Alumina particles having an average particle size of 300 μm were used, and the blending amount and firing conditions were changed to produce a plurality of gas pipes 10 (samples 1 to 9) having different porosities of the ceramic porous body 5. The gas pipes 10 thus obtained were subjected to measurement of the air permeability and an Ar gas flow test. The measurement of the air permeability was performed using a 30 mm gas pipe 10, and the Ar gas flow test was performed using a 100 mm gas pipe 10. The results are shown in FIG. 4.
　気孔率は、アルキメデス法によって測定した。また、通気量は、ガス配管１０に流量を増加させながらＡｒガスを流通させ、圧力損失が０．４９ｋＰａとなったときの１分当たりのガス流量（ｍｌ／ｃｍ２／分）を測定した。通気量が４００（ｍｌ／ｃｍ２／分）以上の試料を「Ａ」、通気量が２００（ｍｌ／ｃｍ２／分）以上４００（ｍｌ／ｃｍ２／分）未満の試料を「Ｂ」、通気量が２００（ｍｌ／ｃｍ２／分）未満の試料を「Ｃ」とした。通気量が２００（ｍｌ／ｃｍ２／分）以上であれば、ガス配管として十分にガス流路が確保されていると評価できる。 The porosity was measured by the Archimedes method. The amount of airflow was measured by passing Ar gas through the gas pipe 10 while increasing the flow rate, and measuring the gas flow rate per minute (ml/cm 2 /min) when the pressure loss reached 0.49 kPa. Samples with an airflow rate of 400 (ml/cm 2 /min) or more were classified as "A", samples with an airflow rate of 200 (ml/cm 2 /min) or more and less than 400 (ml/cm 2 /min) were classified as "B", and samples with an airflow rate of less than 200 (ml/cm 2 /min) were classified as "C". If the amount of airflow is 200 (ml/cm 2 /min) or more, it can be evaluated that a sufficient gas flow path is secured as a gas pipe.
　Ａｒガス流通試験は、ガス配管１０に圧力損失が０．４９ｋＰａとなる条件でＡｒガスを流通させ、放電の発生の有無を目視で測定した。放電が発生しなかった試料を「Ａ」、放電が１～３か所で発生した試料を「Ｂ」、放電が４か所以上で発生した試料を「Ｃ」とした。高温の真空空間で電圧が印加される環境にＡｒガスを供給するガス配管としては、「Ａ」評価または「Ｂ」評価であれば十分に合格レベルである。また、Ａｒガス流通試験後のガス配管１０について、目視で観察し、多孔質部の端面の割れの発生の有無を観察した。割れが確認されなかった試料を「〇」とし、割れが確認された試料を「×」とした。 In the Ar gas flow test, Ar gas was passed through the gas pipe 10 under conditions that resulted in a pressure loss of 0.49 kPa, and the occurrence of discharge was visually measured. Samples in which no discharge occurred were rated "A", samples in which discharge occurred in 1-3 places were rated "B", and samples in which discharge occurred in 4 or more places were rated "C". For gas pipes that supply Ar gas to an environment in which voltage is applied in a high-temperature vacuum space, an "A" or "B" rating is a sufficient pass level. In addition, the gas pipe 10 after the Ar gas flow test was visually observed to see whether cracks had occurred on the end faces of the porous portion. Samples in which no cracks were found were rated "Good", and samples in which cracks were found were rated "Poor".
　図４に示すように、通気量は、試料１～９の全てにおいて良好な結果が得られた（評価「Ａ」又は「Ｂ」）。特に、気孔率が３０％以上の試料（試料３～７）は、４００（ｍｌ／ｃｍ２／分）以上の通気量（評価「Ａ」）が得られ、ガス配管として良好な通気量が得られることが確認された。また、気孔率が４５％以下の試料（試料１～６）は、Ａｒガス流通試験の結果が「Ａ」又は「Ｂ」であり、放電の発生が抑制されることが確認された。特に、気孔率が４０％以下の試料（試料１～５）は、放電が発生せず、良好な結果が得られることが確認された。ガス配管の通気量、Ａｒガス流通試験の結果を考慮すると、ガス配管（セラミックス多孔体）の気孔率が３０％以上４５％以下であれば、通気性に優れ、放電の発生が抑制されたガス配管が得られることが確認された。 As shown in FIG. 4, good results were obtained for the amount of air permeation in all of samples 1 to 9 (evaluation "A" or "B"). In particular, samples with a porosity of 30% or more (samples 3 to 7) obtained an amount of air permeation of 400 (ml/cm 2 /min) or more (evaluation "A"), and it was confirmed that a good amount of air permeation was obtained as a gas pipe. In addition, samples with a porosity of 45% or less (samples 1 to 6) obtained the results of the Ar gas flow test as "A" or "B", and it was confirmed that the occurrence of discharge was suppressed. In particular, it was confirmed that samples with a porosity of 40% or less (samples 1 to 5) did not generate discharge and obtained good results. Considering the amount of air permeation in the gas pipe and the results of the Ar gas flow test, it was confirmed that if the porosity of the gas pipe (porous ceramic body) is 30% or more and 45% or less, a gas pipe with excellent air permeability and suppressed occurrence of discharge can be obtained.
（実験例２）
　平均粒子径の異なるアルミナ粒子（骨材）を用意し、配合量及び焼成条件を変化させ、セラミックス多孔体５の気孔率が３５％のガス配管１０（試料１１～２３）を作製した。試料１１～２２について、ガス配管１０の成形性及び焼成歩留について評価した。結果を図５に示す。 (Experimental Example 2)
Alumina particles (aggregates) with different average particle sizes were prepared, and the blending amounts and firing conditions were changed to produce gas pipes 10 (samples 11 to 23) with a porosity of the ceramic porous body 5 of 35%. Samples 11 to 22 were evaluated for moldability and firing yield of the gas pipes 10. The results are shown in FIG.
　成形性については、外管２内にセラミックス多孔体５の原料を充填する際、セラミックス多孔体５の形が保たれたものを○、セラミックス多孔体５の形が崩壊したものを×とした。また、焼成歩留については、セラミックス多孔体５の断面をＳＥＭ観察し、８０％以上のアルミナ粒子がガラスボンドで結合されている試料を「Ａ」、６０％以上８０％未満のアルミナ粒子がガラスボンドで結合されている試料を「Ｂ」、４０％以上６０％未満のアルミナ粒子がガラスボンドで結合されている試料を「Ｃ」、４０％未満のアルミナ粒子がガラスボンドで結合されている試料を「Ｄ」とした。 Regarding moldability, when the raw material for the ceramic porous body 5 was filled into the outer tube 2, the shape of the ceramic porous body 5 was maintained, and the shape of the ceramic porous body 5 was broken, which was marked with an "O" and an "X". Regarding the firing yield, the cross section of the ceramic porous body 5 was observed with an SEM, and samples in which 80% or more of the alumina particles were bonded with glass bonds were marked with an "A", samples in which 60% to less than 80% of the alumina particles were bonded with glass bonds were marked with a "B", samples in which 40% to less than 60% of the alumina particles were bonded with glass bonds were marked with a "C", and samples in which less than 40% of the alumina particles were bonded with glass bonds were marked with a "D".
　図５に示すように、アルミナ粒子の平均粒子径が６００μｍ以下の試料（試料１１～２１）は、成形性が良好であり、外管２内にセラミックス多孔体５の原料を確実に充填できることが確認された。また、アルミナ粒子の平均粒子径が８０μｍ以上の試料（試料１４～２３）は、焼成歩留の結果が「Ａ」又は「Ｂ」であり、アルミナ粒子間がガラスボンドで十分に結合されていることが確認された。特に、アルミナ粒子の平均粒子径が１００μｍ以上５００μｍ以下の試料は、８０％以上のアルミナ粒子がガラスボンドで結合されており、焼成歩留が特に良好であることが確認された。ガス配管の成形性、焼成歩留を考慮すると、アルミナ粒子（骨材）の平均粒子径が５０μｍ以上６００μｍ以下であれば、安定してガス配管を製造できることが確認された。 As shown in Figure 5, it was confirmed that samples with an average particle size of alumina particles of 600 μm or less (samples 11 to 21) had good moldability, and that the raw material of the ceramic porous body 5 could be reliably filled into the outer tube 2. In addition, samples with an average particle size of alumina particles of 80 μm or more (samples 14 to 23) had a sintering yield result of "A" or "B", and that the alumina particles were sufficiently bonded with glass bonds. In particular, samples with an average particle size of alumina particles of 100 μm or more and 500 μm or less were confirmed to have particularly good sintering yields, with 80% or more of the alumina particles bonded with glass bonds. Considering the moldability and sintering yield of gas piping, it was confirmed that gas piping can be stably manufactured if the average particle size of the alumina particles (aggregate) is 50 μm or more and 600 μm or less.
（実験例３）
　平均粒子径の異なるアルミナ粒子（骨材）を用いて、セラミックス多孔体５の気孔率が３０％であり、通気量が異なるガス配管１０（試料３１～４０）を作製した。試料３１～４０について、実験例１と同様のＡｒガス流通試験を行った。図６にＡｒガス流通試験の結果を示す。 (Experimental Example 3)
Gas pipes 10 (samples 31 to 40) having different gas permeabilities were fabricated using alumina particles (aggregates) with different average particle sizes and a ceramic porous body 5 with a porosity of 30%. Samples 31 to 40 were subjected to an Ar gas flow test similar to that of Experimental Example 1. The results of the Ar gas flow test are shown in FIG. 6.
　図６に示すように、試料３１～４０の全てにおいて良好な結果が得られた（評価「Ａ」又は「Ｂ」）。特に、通気量が１２００ｍｌ／ｃｍ２／分以下の試料（試料３１～３９）は放電が発生せず、特に良好な結果が得られることが確認された。なお、本実験例の結果と実験例１の結果を併せて考慮すると、ガス配管１０の通気量（ｍｌ／ｃｍ２／分）は、４２０以上１０５０以下であることが特に好ましい。 As shown in Fig. 6, good results were obtained for all of Samples 31 to 40 (evaluated as "A" or "B"). In particular, it was confirmed that the samples with an airflow rate of 1200 ml/ cm2 /min or less (Samples 31 to 39) did not generate discharge and gave particularly good results. Considering the results of this experiment together with the results of Experiment 1, it is particularly preferable that the airflow rate (ml/ cm2 /min) of the gas pipe 10 is 420 or more and 1050 or less.
　以上、本発明の具体例を詳細に説明したが、これらは例示に過ぎず、請求の範囲を限定するものではない。請求の範囲に記載の技術には、以上に例示した具体例を様々に変形、変更したものが含まれる。また、本明細書または図面に説明した技術要素は、単独であるいは各種の組合せによって技術的有用性を発揮するものであり、出願時請求項記載の組合せに限定されるものではない。また、本明細書または図面に例示した技術は複数目的を同時に達成し得るものであり、そのうちの一つの目的を達成すること自体で技術的有用性を持つものである。 　Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. Furthermore, the technical elements described in this specification or drawings exert technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of those objectives is itself technically useful.

Claims (19)

  1. 　外管内にセラミックス多孔体が充填されているガス配管で用いられるセラミックス多孔体であって、
    　気孔率が２０％以上６０％以下である、セラミックス多孔体。     A ceramic porous body used in a gas piping in which an outer pipe is filled with the ceramic porous body,
    A ceramic porous body having a porosity of 20% or more and 60% or less.
  2. 　気孔率が３０％以上４５％以下である、請求項１に記載のセラミックス多孔体。 The ceramic porous body according to claim 1, having a porosity of 30% or more and 45% or less.
  3. 　気孔率が３０％以上４０％以下である、請求項２に記載のセラミックス多孔体。 The ceramic porous body according to claim 2, having a porosity of 30% or more and 40% or less.
  4. 　セラミックス多孔体を構成している骨材の平均粒子径が、４５μｍ以上６００μｍ以下である、請求項１から３のいずれか一項に記載のセラミックス多孔体。 The ceramic porous body according to any one of claims 1 to 3, wherein the average particle size of the aggregate constituting the ceramic porous body is 45 μm or more and 600 μm or less.
  5. 　セラミックス多孔体が、ＳｉＯ２を５～２０質量％、Ａｌ２Ｏ３を８０～９５質量％含む、請求項１から３のいずれか一項に記載のセラミックス多孔体。 The ceramic porous body according to any one of claims 1 to 3, comprising 5 to 20 mass% of SiO2 and 80 to 95 mass% of Al2O3 .
  6. 　セラミックス多孔体が、ＳｉＯ２を５～２０質量％、Ａｌ２Ｏ３を８０～９５質量％含む、請求項４に記載のセラミックス多孔体。 The ceramic porous body according to claim 4, comprising 5 to 20 mass% of SiO 2 and 80 to 95 mass% of Al 2 O 3 .
  7. 　セラミックス多孔体を構成している骨材の平均粒子径が、８０μｍ以上６００μｍ以下である、請求項４に記載のセラミックス多孔体。 The ceramic porous body according to claim 4, wherein the average particle size of the aggregate constituting the ceramic porous body is 80 μm or more and 600 μm or less.
  8. 　骨材の平均粒子径が、１００μｍ以上５００μｍ以下である、請求項７に記載のセラミックス多孔体。 The ceramic porous body according to claim 7, wherein the average particle size of the aggregate is 100 μm or more and 500 μm or less.
  9. 　セラミックス多孔体を外管に充填したガス配管にガスを流通させたときの１分当たりの通気量が、４２０ｍｌ／ｃｍ２以上１６８０ｍｌ／ｃｍ２以下である、請求項１に記載のセラミックス多孔体。 2. The ceramic porous body according to claim 1, wherein when gas is passed through a gas pipe having an outer tube filled with the ceramic porous body, the amount of air permeation per minute is 420 ml/ cm2 or more and 1680 ml/ cm2 or less.
  10. 　１分当たりの通気量が、４２０ｍｌ／ｃｍ２以上１０５０ｍｌ／ｃｍ２以下である、請求項９に記載のセラミックス多孔体。 10. The ceramic porous body according to claim 9, having an air permeability per minute of 420 ml/ cm2 or more and 1050 ml/ cm2 or less.
  11. 　セラミックス多孔体を構成している主骨材の材料が、アルミナ、シリカ、炭化ケイ素、ムライト、ジルコニア又はコージェライトである請求項１に記載のセラミックス多孔体。 The ceramic porous body according to claim 1, wherein the main aggregate material constituting the ceramic porous body is alumina, silica, silicon carbide, mullite, zirconia or cordierite.
  12. 　セラミックス多孔体が、Ｆｅ２Ｏ３、ＴｉＯ２、ＣａＯ、ＭｇＯ、Ｎａ２Ｏから選択される化合物の少なくとも１つを微量成分として含む請求項１１に記載のセラミックス多孔体。 The ceramic porous body according to claim 11, which contains at least one compound selected from the group consisting of Fe2O3 , TiO2 , CaO, MgO and Na2O as a trace component.
  13. 　前記微量成分が、Ｆｅ２Ｏ３：０．０１～５％、ＣａＯ：０．１～５％、ＭｇＯ：０．１～５％、Ｎａ２Ｏ：０．５～４％の割合で含まれている請求項１２に記載のセラミックス多孔体。 The ceramic porous body according to claim 12, wherein the trace components are contained in the following proportions: Fe 2 O 3 : 0.01-5%, CaO: 0.1-5%, MgO: 0.1-5%, and Na 2 O: 0.5-4%.
  14. 　前記骨材がガラスボンドで結合されている請求項１１から１３のいずれか一項に記載のセラミックス多孔体。 The ceramic porous body according to any one of claims 11 to 13, wherein the aggregate is bonded with a glass bond.
  15. 　外管と、
    　前記外管の内部に充填されているセラミックス多孔体と、を有し、
    　前記セラミックス多孔体の気孔率が、２０％以上６０％以下である、ガス配管。     An outer tube,
    A ceramic porous body filled inside the outer tube,
    A gas pipe, wherein the porosity of the ceramic porous body is 20% or more and 60% or less.
  16. 　前記外管がセラミックス製である請求項１５に記載のガス配管。 The gas pipe according to claim 15, wherein the outer tube is made of ceramics.
  17. 　前記外管の気孔率が５％以下である請求項１５に記載のガス配管。 The gas pipe according to claim 15, wherein the porosity of the outer tube is 5% or less.
  18. 　前記セラミックス多孔体を構成しているセラミックス粒子の平均粒子径が４５μｍ以上６００μｍ以下である請求項１５から１７のいずれか一項に記載のガス配管。 The gas pipe according to any one of claims 15 to 17, wherein the average particle diameter of the ceramic particles constituting the ceramic porous body is 45 μm or more and 600 μm or less.
  19. 　前記セラミックス粒子が、ＳｉＯ２を５～２０質量％、Ａｌ２Ｏ３を８０～９５質量％含む、請求項１８に記載のガス配管。 The gas pipe according to claim 18, wherein the ceramic particles contain 5 to 20 mass % of SiO2 and 80 to 95 mass % of Al2O3 .
PCT/JP2023/032052 2022-09-29 2023-09-01 Ceramic porous body and gas pipe WO2024070496A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08319582A (en) * 1995-05-19 1996-12-03 Isuzu Ceramics Kenkyusho:Kk Insulating ceramics film on surface of metal and its formation
JP2004057028A (en) * 2002-07-25 2004-02-26 Toshiba Ceramics Co Ltd Member for cell culture and artificial organ using the same
JP2012167543A (en) * 2011-02-09 2012-09-06 Ibiden Co Ltd Structure, and method of manufacturing the same
JP2018525574A (en) * 2015-05-19 2018-09-06 ビーエーエスエフ ソシエタス・ヨーロピアＢａｓｆ Ｓｅ Airtight and heat permeable multilayer ceramic composite tube
WO2022014613A1 (en) * 2020-07-13 2022-01-20 日本碍子株式会社 Exhaust pipe

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08319582A (en) * 1995-05-19 1996-12-03 Isuzu Ceramics Kenkyusho:Kk Insulating ceramics film on surface of metal and its formation
JP2004057028A (en) * 2002-07-25 2004-02-26 Toshiba Ceramics Co Ltd Member for cell culture and artificial organ using the same
JP2012167543A (en) * 2011-02-09 2012-09-06 Ibiden Co Ltd Structure, and method of manufacturing the same
JP2018525574A (en) * 2015-05-19 2018-09-06 ビーエーエスエフ ソシエタス・ヨーロピアＢａｓｆ Ｓｅ Airtight and heat permeable multilayer ceramic composite tube
WO2022014613A1 (en) * 2020-07-13 2022-01-20 日本碍子株式会社 Exhaust pipe

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