JP4166350B2 - Oxidation-resistant boron carbide-silicon carbide composite carbon material, sintering crucible using the same, vacuum evaporation crucible, and high-temperature firing jig - Google Patents
Oxidation-resistant boron carbide-silicon carbide composite carbon material, sintering crucible using the same, vacuum evaporation crucible, and high-temperature firing jig Download PDFInfo
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- JP4166350B2 JP4166350B2 JP33590598A JP33590598A JP4166350B2 JP 4166350 B2 JP4166350 B2 JP 4166350B2 JP 33590598 A JP33590598 A JP 33590598A JP 33590598 A JP33590598 A JP 33590598A JP 4166350 B2 JP4166350 B2 JP 4166350B2
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- 229910010271 silicon carbide Inorganic materials 0.000 title claims description 98
- 239000002131 composite material Substances 0.000 title claims description 71
- 239000003575 carbonaceous material Substances 0.000 title claims description 51
- 230000003647 oxidation Effects 0.000 title claims description 39
- 238000007254 oxidation reaction Methods 0.000 title claims description 39
- 238000005245 sintering Methods 0.000 title claims description 20
- 238000010304 firing Methods 0.000 title claims description 17
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 title claims description 11
- 229910052796 boron Inorganic materials 0.000 title claims description 11
- 238000007738 vacuum evaporation Methods 0.000 title claims description 5
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 52
- 239000010410 layer Substances 0.000 claims description 45
- 239000000758 substrate Substances 0.000 claims description 38
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- 238000006243 chemical reaction Methods 0.000 claims description 11
- 229910052580 B4C Inorganic materials 0.000 claims description 7
- INAHAJYZKVIDIZ-UHFFFAOYSA-N boron carbide Chemical compound B12B3B4C32B41 INAHAJYZKVIDIZ-UHFFFAOYSA-N 0.000 claims description 7
- 239000000203 mixture Substances 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 89
- 229910052799 carbon Inorganic materials 0.000 description 66
- 239000000463 material Substances 0.000 description 34
- 229910052751 metal Inorganic materials 0.000 description 32
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- FVBUAEGBCNSCDD-UHFFFAOYSA-N silicide(4-) Chemical compound [Si-4] FVBUAEGBCNSCDD-UHFFFAOYSA-N 0.000 description 8
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- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
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- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
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- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
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- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 description 1
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Images
Classifications
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/009—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone characterised by the material treated
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B35/00—Transporting of glass products during their manufacture, e.g. hot glass lenses, prisms
- C03B35/14—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands
- C03B35/16—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands by roller conveyors
- C03B35/18—Construction of the conveyor rollers ; Materials, coatings or coverings thereof
- C03B35/181—Materials, coatings, loose coverings or sleeves thereof
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B35/00—Transporting of glass products during their manufacture, e.g. hot glass lenses, prisms
- C03B35/14—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands
- C03B35/16—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands by roller conveyors
- C03B35/18—Construction of the conveyor rollers ; Materials, coatings or coverings thereof
- C03B35/185—Construction of the conveyor rollers ; Materials, coatings or coverings thereof having a discontinuous surface for contacting the sheets or ribbons other than cloth or fabric, e.g. having protrusions or depressions, spirally wound cable, projecting discs or tires
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B35/00—Transporting of glass products during their manufacture, e.g. hot glass lenses, prisms
- C03B35/14—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands
- C03B35/16—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands by roller conveyors
- C03B35/18—Construction of the conveyor rollers ; Materials, coatings or coverings thereof
- C03B35/189—Disc rollers
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
- C04B41/52—Multiple coating or impregnating multiple coating or impregnating with the same composition or with compositions only differing in the concentration of the constituents, is classified as single coating or impregnation
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
- Y02P40/57—Improving the yield, e-g- reduction of reject rates
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Ceramic Engineering (AREA)
- Structural Engineering (AREA)
- Continuous Casting (AREA)
- Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)
- Ceramic Products (AREA)
- Physical Vapour Deposition (AREA)
- Heat Treatments In General, Especially Conveying And Cooling (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、高温雰囲気下で使用できる耐酸化性に優れた炭化ホウ素ー炭化ケイ素複合炭素材料（以下Ｂ4 Ｃ−ＳｉＣ複合炭素材料）及びそれを用いた焼結用ルツボ、真空蒸着用ルツボ及び高温焼成用治具に関する。
【０００２】
【従来の技術】
炭素材料は、熱伝導性、耐摩耗性、耐薬品性、高温での機械的特性に優れた特性を有しているため、高純度処理された炭素基材単独で焼結用ルツボ、真空蒸着用ルツボ、連続鋳造用ダイス、溶融金属用ルツボ、ガラス管搬送用ローラー、鋼線材焼鈍用均熱管、高温焼成用治具及びホットプレス用治具等に広く利用されている一方、炭素基材単独では酸化されやすく、酸化消耗に伴う強度劣化や精度劣化による寿命の短命等の問題があった。
【０００３】
上記の問題に対しては、炭素基材表面に、耐酸化性に優れ、炭素と相性の良い炭化ケイ素（以下ＳｉＣ）を被覆する手段が有効であるとされ、ＳｉＣ被覆の一般的手法として化学蒸着法（ＣＶＤ法）、転化法（ＣＶＲ法）等がよく知られている。
【０００４】
ＣＶＤ法で形成されたＳｉＣ層は、非常に緻密で優れたガス不透過性を有しており、耐酸化性の改善には効果的であるが、炭素基材表面に物理的に付着しているだけであり、また、炭素基材との熱膨張率が異なることから、熱衝撃を受けると層の剥離や微小クラックが発生するという欠点がある。そのため、ＳｉＣと熱膨張率の近い炭素基材を用いなければならない。また、その製造方法上、部分的に被覆したり、孔内部への均一な被覆が難しく、製造コストがかかるという問題もある。
【０００５】
一方、ＣＶＲ法は、Ｓｉ又はＳｉＯガスを炭素基材に反応させて基材の表層部又は全体をＳｉＣに転化する方法であり、ＣＶＤ法と異なり、ＳｉＣ層が化学的に形成されるため、ＳｉＣ層の剥離等の問題は解決されるが、その製法に起因して緻密性にかけ、耐酸化性の改善に、あまり効果が無く、ＣＶＤ法同様製造コストがかかるという問題も合わせて有している。
【０００６】
本発明は、上記の問題点を鑑みてなされたものであり、その目的とするところは、ＣＶＤ法やＣＶＲ法に比較して、簡単な方法で耐酸化性、耐摩耗性に優れ、緻密なＳｉＣ層が炭素基材の表層部の所定部位（全面または一部）に、経済的に形成されてなるＢ4 Ｃ−ＳｉＣ複合炭素材料及びそれを用いた焼結用ルツボ、真空蒸着用ルツボ及び高温焼成用治具を提供する点である。
【０００７】
【課題を解決するための手段】
本発明者らは、先に炭素質基材の表面に、Ｓｉ粉末、Ｂ4 Ｃ粉末、熱可塑性樹脂、及び該樹脂の溶媒を含むスラリーを塗布し、乾燥した後、非酸化性雰囲気中で１５００℃以上で熱処理することにより、緻密で耐酸化性、耐摩耗性に優れた新規なＢ4 Ｃ−ＳｉＣ複合炭素材料及び製造方法を提案した（特開平７─１４４９８２号参照）。本発明者らは、その後、試行錯誤の結果、優れた耐酸化性、耐摩耗性を有するに必要な具体的な組成比、各層の厚みを見出し、本発明を完成させるに至ったものである。
【０００８】
請求項１の発明は、炭素基材の表層部の所定部位（全体もしくは一部）に、厚さ１ｍｍ以上のＳｉＣ含有複合層を有し、このＳｉＣ複合層の上に厚さ１〜５０μｍのＢ4 Ｃ−ＳｉＣを含有する最外表層部が形成されてなり、前記炭化ホウ素−炭化ケイ素含有複合層の炭化ホウ素と炭化ケイ素の２成分についての組成比（重量％）が、炭化ケイ素／炭化ホウ素＝７８〜９７／３〜２２であることを特徴とする耐酸化性の炭化ホウ素−炭化ケイ素複合炭素材料である。
【０００９】
請求項２の発明は、請求項１において、前記炭素質基材の表面に金属Ｓｉが存在していないことを特徴とする請求項１記載の炭化ホウ素−炭化ケイ素複合炭素材料である。
【００１０】
請求項３の発明は、請求項１において、前記ＳｉＣ含有複合層における前記炭化ケイ素化率が深さ方向に略均一である請求項１記載の炭化ホウ素ー炭化ケイ素複合炭素材料である。
【００１１】
請求項４の発明は、請求項１〜３のいずれか一項に記載の複合炭素材料の表層部の一部又は全部を用いてなる焼結用ルツボである。
【００１２】
請求項５の発明は、請求項１〜３のいずれか一項に記載の複合炭素材料の表層部の一部又は全部を用いてなる真空蒸着用ルツボである。
【００１７】
請求項６の発明は、請求項１〜３のいずれか一項に記載の複合炭素材料を表層部の一部又は全部に用いてなる高温焼成用治具である。
【００１９】
本発明のＢ4 Ｃ−ＳｉＣ複合炭素材料に係る最外表層部には、少なくともＢ4 Ｃ成分が含まれている必要があり、また周囲に混在するＳｉＣと必ずしも均質に混じり合った状態で分布している必要はない。この、最外表層部のＢ4 Ｃは酸化されやすく、高温酸化雰囲気中でＢ2 Ｏ3 を形成し、ガラス質のＢ2 Ｏ3 が形成されることによってＳｉとの共晶温度が低下し、最終的にＳｉＯ2 −Ｂ2 Ｏ3 系のガラス質が形成され、このガラスが最外表面層をさらに被覆し、緻密な酸化保護皮膜を形成することになる。従って、最外層にガス不透過性に優れた緻密な酸化保護皮膜が形成された状態になる。
【００２０】
このような機能を有する最外表層部は、あまり厚すぎると、割れや欠けが生じ易くなるため、厚みとしては３〜２０μｍ、望ましくは５〜１５μｍとなるように形成しておく。最外表層部の厚みをこのように設定する事により、Ｂ2 Ｏ3 による耐酸化性の効果を十分に発揮させつつも、必要以上の最外表層部の形成に要する製造コストの無駄を省き、製品コストの上昇を防止する事ができる。
【００２１】
ＳｉＣとＢ4 Ｃの組成比としてはＳｉＣ成分が７８〜９９重量％、Ｂ4 Ｃ成分が１〜２２重量％であるものが望ましい。この範囲にある２元組成（ＳｉＣ、Ｂ4 Ｃ）を含む最外層表層部を有するＳｉＣ層が形成されている場合に、最も効率よく耐酸化性が付与されたＢ4 Ｃ−ＳｉＣ複合炭素材料とすることができるからである。さらに言えば、Ｂ4 Ｃは３〜２０重量％が望ましい。ＳｉＣ含有複合層の形成を促進させるうえで、下限として３重量％以上が好ましく、又最外表層部が高温酸化されたとき、その最外表層部にＳｉＯ2 ─Ｂ2 Ｏ3 系のガラス質が形成されるだけのＢ4 Ｃが存在すれば十分であり、この点を考慮すると、上限として２０重量％以下が好ましいからである。
【００２２】
以上説明した最外表層部に続くＳｉＣ含有複合層は、少なくともＳｉＣを含む必要がある。このＳｉＣ含有複合層は、耐酸化性を付与する。仮に最外表層部のＳｉＯ2 ─Ｂ2 Ｏ3 のガラス質酸化保護膜が無くなった場合でも、このＳｉＣ含有複合層のＳｉＣにより炭素質基材の酸化進行が抑制される。従って、このような機能を有するＳｉＣ含有複合層は１ｍｍ以上の厚みが必要であるとともに、また、１ｍｍ以上の厚みで形成されるＳｉＣ−Ｃ層は、厚み方向で略均一に形成されることが望ましい。厚み方向での耐酸化性が変化しないからである。ここで、厚み方向の略均一とは、ＳｉＣ含有複合層の浅い所のケイ化率と深い所のケイ化率の比が０．８以内にあることをいう。
【００２３】
このように深くて、均一なＳｉＣ層は次の理由により簡単に形成できる。最外層表面に含まれるＢ4 Ｃは基材内部に浸透せず、何らかの作用、例えば触媒的作用で、炭素基材中にＳｉを浸透させる働きがあり、その結果として、Ｓｉが深さ方向に１ｍｍ以上炭素基材中に拡散し、ＳｉＣ含有複合層に１ｍｍ以上の均一な厚みを有するＳｉＣ層が形成された状態とすることができる。
【００２４】
本発明に使用する炭素基材としては特に限定されるものではなく、炭素のみから実質的になる炭素材料、又は炭素を主成分とする黒鉛化品、例えば高密度等方性黒鉛材等が挙げられ、これら、炭素基材のうち水銀圧入法で測定した平均細孔半径が１μｍ以上である炭素基材を製品形状に加工したものを使用する事が望ましい。
【００２５】
平均細孔半径が１μｍよりも小さい炭素基材を使用すると、ＳｉとＢ4 Ｃを混合したスラリーを炭素基材に塗布する時に、炭素基材の微小細孔にまでスラリーが浸透しにくくなるためあまり望ましくない。なお、炭素基材の平均細孔半径の上限については、特に制限はなく、炭素繊維強化炭素複合材料等の平均細孔半径が大きい炭素基材は、炭素基材内部奥深くまでスラリーが浸透するため、熱処理後にほぼ全体が複合化したものになる。
【００２６】
まず、平均粒径１０〜１００μｍのＳｉ粉末、平均粒径５〜１００μｍのＢ4 Ｃ粉末、熱可塑性樹脂及びその樹脂の溶媒からなるスラリーを準備する。ここで使用する熱可塑性樹脂は造膜性が高く、かつ残炭率が低い樹脂を使用し、例えばポリアミドイミド、ポリビニルアルコール、ポリアミド樹脂の内より選ばれたものが特に好ましい。中でもポリアミドが更に望ましく、ジメチルアセトアミド、ジメチルホルムアミド、ジメチルスルホキサイド、Ｎメチル─２ピロリドン等の溶媒に溶解させて使用する。
【００２７】
しかしながら、樹脂として残炭率の高い樹脂、例えばフルフリルアルコール、フェノール樹脂等の熱硬化性樹脂を使用すると、後の工程で高温熱処理を行ったときに炭素基材の表面に樹脂の炭化物、Ｓｉ及びＢ4 Ｃとの反応生成物が固着して、これらを容易に除去できなくなることがあるため好ましくない。
【００２８】
Ｓｉ粉末とＢ4 Ｃ粉末を混合する際の混合割合は、Ｓｉ粉末８０〜９７重量％に対してＢ4 Ｃ粉末３〜２０重量％が望ましい。Ｂ4 Ｃ粉末が３重量％未満では、Ｂ4 Ｃ粉末の混合による効果が少ないからである。具体的には、Ｂ4 Ｃ粉末を混合することにより、Ｂ4 Ｃによる何らかの作用、例えば、触媒的作用効果が発現する。すなわち、３重量％未満では、この効果があまり発現せず、高温熱処理後も溶融Ｓｉが炭素基材中の気孔に完全に浸透せず、冷却後炭素基材表面に金属Ｓｉとして固着した状態で残ってしまう。逆に３重量％以上含有させた場合は、溶融Ｓｉが気孔中に深くまで浸透し、炭素基材との反応が進み、ＳｉＣ化され、請求項１記載の厚みで深さ方向に均一なＳｉＣ層が形成されやすくなるという効果が得られるからである。
【００２９】
この場合、炭素基材の表面には金属Ｓｉとしての残留物は存在せず、使用した樹脂の炭化物、ＳｉＣ、Ｂ4 Ｃの成分の残留物が残るが、本発明では、この残留物を残せる程度にＢ4 Ｃ粉末を添加すれば十分であるので、Ｂ4 Ｃ粉末の上限は２０重量％程度が望ましい。もちろん要求仕様に応じて、２０％以上のＢ4 Ｃ粉末を添加してＳｉＣ層をより深めに形成させ、耐酸化性の更なる向上及び耐磨耗性やそれ以外の特性の向上を付加させた製品とすることも可能である。
【００３０】
上記のように調製されたスラリーをはけ塗り、へら塗り等の適宜な手段で表面全体、又は必要な部分に塗布する。また、スラリー中に浸漬しても良い。この時に塗布する厚みについては、任意の厚みとすることができるが炭素基材表面から１〜２ｍｍが望ましい。１００μｍ未満ではＳｉＣ層の形成が浅くなり、好ましくない。この後、約８０℃から２００℃まで５時間乾燥することにより、溶媒を揮散させ、樹脂を完全に硬化させる。こうして得られた材料を、１０Ｔｏｒｒ以下の真空で高温熱処理する。昇温速度は４００℃／時間とし、約１６００〜１８００℃で１時間保持する。加熱手段は特に限定されるものではなく、適当な手段で行えばよい。この操作によって、Ｓｉ成分は溶融し、樹脂の炭化層を通って炭素基材の細孔中に侵入し、炭素と反応してＳｉＣ化する。
【００３１】
前記の一連の処理を得て最終的には、スラリーが塗布された部分に相当する炭素基材の表層部がＳｉＣ層に転化するとともに、その表面には、Ｂ4 Ｃ成分を含む緻密な最外表層部が形成された構造のＢ4 Ｃ−ＳｉＣ複合炭素材料を得ることができる。
【００３２】
このような構造からなるＢ4 Ｃ−ＳｉＣ複合炭素材料であれば、高温で酸化されても、最外表層部にＳｉＯ2 ─Ｂ2 Ｏ3 系ガラスの溶融物が生じ、この溶融物が最外表層部の空隙を埋めるように侵入し、かつ被覆する状態となり新たに酸化保護皮膜が形成された状態となる。この酸化保護皮膜が以後の酸化を抑制する働きを行なうことになる。この結果ＣＶＤ法で得られるＳｉＣ皮膜なみのガス不透過性に優れた緻密な保護皮膜が形成できる。しかも、本発明に係るＢ4 Ｃ−ＳｉＣ複合炭素材料の場合には、ＳｉＣ層を炭素基材の表層部の一部もしくは全体に形成することが容易であり、結局、耐酸化物性に優れたＳｉＣ層が任意の所定部位に経済的に形成されてなる炭素複合材料を提供することができる。
【００３３】
以下に本発明によるＢ4 Ｃ−ＳｉＣ複合炭素材料を用いた具体的な用途例を説明する。
【００３４】
まず、焼結用ルツボに対する適用例を説明する。従来から、焼結用ルツボの炭素基材は、主に還元炉内で等方性高密度黒鉛が使用されているが、焼結処理品を交換する際にルツボ表面が大気中に曝され、大気中の水分等が炭素基材に吸着する。また、還元炉内でも水素ガスと酸素の反応で微量な水分が発生する。これら水分等が酸化源となり、炭素材を酸化させ、又その際に発生するガスがルツボ内の焼結処理品と反応し、処理品の不純物混入の一因となる問題がある。
【００３５】
本発明のＢ4 Ｃ−ＳｉＣ複合炭素材料を前記焼結用ルツボの表面の全部又は一部に適用すると、これらの問題を解決できる。焼結用ルツボ１は、図１に示す形状を有するルツボ２及び上蓋３からなり、大気に直接触れる外表面を、Ｂ4 Ｃ−ＳｉＣ複合炭素材料で形成する。具体的には、ルツボの側面２ａ、底面２ｂ及び上蓋３との合わせ面２ｃと、上蓋３の上面３ａ、側面３ｂとルツボ２との合わせ面３ｃとを本発明によるＢ4 Ｃ−ＳｉＣ複合炭素材料で形成する。
【００３６】
ルツボ１の外表面２ａ、２ｂ、２ｃ、及び上蓋の外表面３ａ、３ｂ、３ｃがガス不透過性の酸化保護皮膜であるＢ4 Ｃ−ＳｉＣ複合炭素材料で形成されているため、ルツボ自身の寿命を伸ばすとともに、ルツボ外部からの不純物ガスの侵入を防ぎ、ルツボ内部の焼結用金属粉末の純度を維持する効果も得られる。
【００３７】
つぎに、真空蒸着用ルツボに対する適用例を説明する。従来から真空蒸着用ルツボは、通常炭素基材の細孔部に溶融金属が浸透しないようにピッチ含浸、焼成等の工程を繰り返し行った炭素材が使用されている。例えば、アルミニウムの様に炭素材と反応する金属の場合、さらに無機材塩類の溶液を含浸、焼成等の処理を行うが、完全に金属との反応を防止することはできないという問題がある。
【００３８】
本発明のＢ4 Ｃ−ＳｉＣ複合炭素材料を前記真空蒸着用ルツボの表面の全部又は一部特に内面に適用すると、これらの問題を解決できる。図２に示すように、本発明の真空蒸着用ルツボ１１は、炭素基材として嵩密度１．９０ｇ／ｃｍ3 以上、固有抵抗１２００μΩｃｍ以下の等方性黒鉛を使用し、該黒鉛を図示の形状に機械加工後、蒸着用溶融金属と接する面であるルツボ内面１１ａに、本発明に係る前記スラリーをはけ塗りし、Ｂ4 Ｃ−ＳｉＣ複合炭素材料を形成してなる。本発明によって得られる真空蒸着用ルツボは、耐酸化性が向上し、ルツボ内の蒸着用溶融金属との反応を抑制することが可能となり、ルツボの寿命を向上させることが可能となる。
【００３９】
つぎに、連続鋳造用部材に対する適用例を説明する。連続鋳造用部材としては、従来から高温機械特性、熱伝導性、潤滑性等の物性面で優れた炭素基材が多く使用されているが、炭素基材単独では非常に酸化しやすく耐摩耗性も十分ではなく、また酸化消耗に伴う強度劣化により早期破損に至等、寿命が非常に短いという欠点がある。
【００４０】
本発明のＢ4 Ｃ−ＳｉＣ複合炭素材料を前記連続鋳造用部材の表面の全部又は一部特に鋳造面に適用すると、これらの問題を解決できる。図３に示すように、連続鋳造用部材２１は、炭素基材として嵩密度が１．７５ｇ／ｃｍ3 以上、平均細孔半径が２．０μｍ以下、曲げ強度が４００ｋｇｆ／ｃｍ2 以上であって、熱伝導率が８０ｋｃａｌ／ｈｒｍ℃以上の等方性黒鉛を、割り型２２，２３に加工してなる。なお、平均細孔半径は、水銀圧入法による測定値（水銀と試料との接触角１４１．３°、最大圧力１０００ｋｇ／ｃｍ2 の時の累積気孔容積の半分の値）を採用した。次に、前記スラリーを、溶湯及び鋳塊２４と接する鋳造面２５のみはけ塗りを行い、該部分にのみ本発明に係るＢ4 Ｃ−ＳｉＣ複合炭素材料を形成する。
【００４１】
ところで、複合処理を施した直後の表面は、処理前の炭素基材表面に比べて粗くなっており、このような表面のままでダイスとして使用した場合、冷却・凝固した鋳塊を間欠的に引き出す時に両者間に大きな摩擦力が作用し、ダイス内面が鋳塊により傷つけられ、この傷が鋳塊に転写されて鋳塊表面を粗くするおそれがあるからである。従って、必ず連続鋳造用部材の内面は鏡面加工を行う。鏡面加工の手段としては、特別限定はなく、例えばダイス砥粒による湿式研磨方法が挙げられる。また、最終的な研磨度としては、ＪＩＳ平均表面粗さ（Ｒａ）で０．７５μｍ以下であれば良い。なお、鏡面加工後の面（ＳｉＣ転化層）の熱伝導率はほぼ５０kcal/hrm℃確保されていれば、金属の冷却凝固能力としては十分である。
【００４２】
上記の如く、本発明で得られる連続鋳造用部材は、炭素基材の溶融金属及び鋳塊と接する部分にＳｉＣの被覆層が深めに形成された後、鏡面加工を施したＢ4 Ｃ−ＳｉＣ複合層が設けられた構造である。このため、炭素基材の表面をＢ4 Ｃ−ＳｉＣ複合層で覆うことにより、本発明の目的である耐酸化性及び耐摩耗性の向上を、確実に実効あるものにできる。その結果、この連続鋳造用部材の一層の延命化を可能とし、同時に鋳肌の滑らかな鋳塊を長時間安定して確実に製造することができる。
【００４３】
つぎに、溶融金属用ルツボに対する適用例を説明する。溶融金属用ルツボは、炭素基材として等方性高密度黒鉛が多く用いられているが、その多くは常圧大気中で使用されるため大気により酸化されたり、ルツボ内部が溶融金属と反応するなどの問題がある。
【００４４】
本発明のＢ４ Ｃ−ＳｉＣ複合炭素材料を前記溶融金属ルツボの表面の全部又は一部特に内面に適用すると、これらの問題を解決できる。図４に示すように、溶融金属用ルツボ３１は、炭素基材を図示の形状に加工し、溶融金属と接するルツボ内面３２に本発明に係るＢ４Ｃ−ＳｉＣ複合炭素材料が形成されてなる。
【００４５】
本発明によるＣ−Ｂ4 Ｃ−ＳｉＣ複合層をルツボ内面に形成させることにより、溶融金属との反応を抑制でき、ルツボの延命化が可能となる。
【００４６】
つぎに、ガラス管搬送用ローラーに対する適用例を説明する。ガラス管搬送用ローラーには、鋳鉄が使用されていたが、製品であるガラス管に傷を付ける点、酸化劣化による整形精度が低下する点などに問題があった。そこで、製品に傷を付けない事を目的に、鋳鉄に替え炭素材が使用されるようになったが、炭素材単独では酸化消耗による強度劣化、ガラス管の整形精度の劣化等の問題があり、耐酸化性に優れた炭素材が要求されている。
【００４７】
本発明のＢ４ Ｃ−ＳｉＣ複合炭素材料を前記ガラス管搬送用ローラーの表面の全部又は一部特に鋳造面に適用すると、これらの問題を解決できる。図５に示すように、ガラス管搬送用ローラー４１は、一本の軸に円板二枚を取り付けた図示の形状に炭素基材を加工し、好ましくはその全面に本発明に係るＢ４Ｃ−ＳｉＣ複合炭素材料が形成されてなる。
【００４８】
全面にＢ4 Ｃ−ＳｉＣ複合層を形成させることにより、該表面層のガラスによる酸化を抑制するため、酸化による整形精度の劣化を防ぐとともに、ローラーの延命化も可能となる。
【００４９】
つぎに、鋼線材焼鈍用均熱管に対する適用例を説明する。鋼線材を焼鈍する工程において、従来、線材はステンレス単独でなる均熱管内を摺動をともなって、移動し処理が行なわれていた。その際、ステンレス均熱管と線材の溶着により、製品線材に傷が発生する問題が多々有り、その防止策として、炭素管をステンレス均熱管に挿入し、線材の溶着防止が行なわれていた。しかしながら、この場合、炭素管の酸化消耗や、線材への侵炭等の問題が新たに発生し、炭素材に代わる鋼線材焼鈍用均熱管向けの材料が要望されている。
【００５０】
本発明のＢ4 Ｃ−ＳｉＣ複合炭素材料を、前記鋼線材焼鈍用均熱管に挿入する炭素管の内表面全面に形成させる。図６に鋼線材焼鈍用均熱管の一例の断面概略図を示す。本発明のＢ4 ＣーＳｉＣ複合層を炭素管５２の内表面、好ましくは全面に形成することにより、耐酸化性が向上するとともに、鋼線材５３の炭素管５２への溶着が防止でき、加えて、鋼線材５３への侵炭が防止できる。また、本発明品の有する優れた潤滑性によって、線材に傷を付けることがなくなり、鋼線材の品質が安定し且つ歩留りが大きく改善される。
【００５１】
つぎに、高温焼成用治具に対する適用例を説明する。高温焼成用治具としては、焼成炉用棚板、金属ろう付け用治具等の高温雰囲気下で使用される治具であり、黒鉛材やステンレス材が使用されていた。しかしながら、前述してきたように高温雰囲気下では黒鉛材を使用した場合、酸化の問題や、処理表面への浸炭の問題があり、また、ステンレス材の場合は、熱歪み等による経時形状変化によって、製品寸法の精度劣化等の問題があった。
【００５２】
本発明のＢ4 Ｃ−ＳｉＣ複合材料を、高温雰囲気下で処理表面と接する部分に形成させる。これにより、前記問題を解消することができ、経時形状変化がなく、耐酸化特性に優れた炭素製の高温焼成用治具とすることが可能となる。
【００５３】
次に、ホットプレス用治具に対する適用例を説明する。ホットプレスに使用されているダイスや、上下のパンチ等の治具は、黒鉛の優れた高温特性のため、従来より黒鉛がよく使用されている。その際には、処理品との溶着を防止するため、治具表面に離型剤を塗布する必要があった。この離型剤は、処理物への不純物混入の原因となっていた。
【００５４】
そこで、本発明のＢ4 Ｃ−ＳｉＣ複合材料を、ホットプレスの上下パンチおよびダイス表面に形成させることにより、表面の酸化を防止することが出来るとともに、処理表面への不純物の混入も少なくなり、離型剤を最小限に抑えることが出来る。ホットプレス用治具は図７に示すように一体型若しくは分割型のダイス６１と上下パンチ６２、６３から構成されている。
【００５５】
【実施例】
以下に実施例を示し、本発明を具体的に説明する。
（実施例１）
炭素基材として、嵩密度１．７７ｇ／ｃｍ3 、平均細孔半径が１．５μｍ、曲げ強度が４００ｋｇｆ／ｃｍ2 の等方性黒鉛（東洋炭素（株）製) を、図１に示す形状を有するルツボとその上蓋に加工した。また、バインダーとしてのポリビニールアルコール（日本合成産業（株）製）８％溶液を分散媒とした。ケイ素粉末（和光純薬工業（株）製、平均粒度４０μｍ）と、炭化ホウ素粉末（共立窯業社製、平均粒度２０μｍ）を重量比で８０：２０の比率に混合し、分散媒中に混合分散させてスラリーとした。
【００５６】
このスラリーを、炭素基材が、大気に直接触れる外表面であるルツボ及び上蓋の所定部分にはけで塗布した後、乾燥機の中で２００℃で溶媒を蒸発させ、さらに３Ｔｏｒｒの窒素ガス雰囲気下、真空加熱炉において１６００℃まで４時間で昇温し、１時間保持した後、冷却して取り出した。ケイ化部の厚みは３ｍｍであった。Ｂ4 Ｃを含む最外表層部は１０μｍであった。また、ケイ化部の浅い所のケイ化率と深い所のケイ化率の比は、０．８であった。
【００５７】
（比較例１）
実施例１と同一材質の等方性黒鉛（東洋炭素（株）製）を使用し、図１に示す形状に加工し、試験用焼結用ルツボを得た。
【００５８】
前記実施例１及び比較例１で得られた試験用焼結用ルツボを用いて、焼結用金属として黒鉛粉末とタングステン粉末を混合した状態で炭化タングステンの焼結試験を行った。
【００５９】
（実施例２）
炭素基材として、嵩密度１．９ｇ／ｃｍ3 、平均細孔半径が０．４μm 、曲げ強度が６５０ｋｇｆ／ｃｍ2 、固有抵抗１２００μΩcm以下の等方性黒鉛（東洋炭素( 株）製) を、図２に示す形状を有するルツボに加工し、溶融金属と接するルツボ内面６に、実施例１と同様の手順により、ケイ化処理を行った試験用真空蒸着用ルツボを得た。ケイ化部の厚みは２ｍｍであった。Ｂ4 Ｃを含む最外表層部は８μｍであった。また、ケイ化部の浅い所のケイ化率と深い所のケイ化率の比は、０．８であった。
【００６０】
（比較例２）
実施例２と同一材質の等方性黒鉛（東洋炭素（株）製）を使用し、図２に示す形状に加工し、試験用真空蒸着用ルツボを得た。
【００６１】
前記実施例２及び比較例２で得られた試験用真空蒸着用ルツボを用いて、蒸着用溶融金属としてアルミニウムを用い、真空蒸着試験を行った。
【００６２】
（参考例１）
炭素基材として、嵩密度１．８７ｇ／ｃｍ3 、平均細孔半径が１．５μｍ 、曲げ強度が６５０ｋｇｆ／ｃｍ2 、熱伝導率１２０ｋｃａｌ／ｈｍ ℃の等方性黒鉛（東洋炭素( 株）製) を、図３に示す形状を有する角形ダイスに加工し、鋳造面に実施例１と同様の手順により、ケイ化処理を行った試験用連続鋳造用ダイスを得た。ケイ化部の厚みは２ｍｍであった。表面を研磨剤を用いてＲａ＝０．７５μｍまで研磨し、試験用連続鋳造用ダイスを得た。
【００６３】
（比較例３）
参考例１と同一材質、同一形状の等方性黒鉛基材（東洋炭素（株）製）を使用し、参考例１と同様の研磨処理を施して、試験用連続鋳造用ダイスを得た。
【００６４】
前記参考例１及び比較例３で得られた試験用連続鋳造用ルツボを用いて、銅合金を用い、連続鋳造試験を行った。
【００６５】
（参考例２）
炭素基材として、嵩密度１．８２ｇ／ｃｍ３ 、平均細孔半径が１μｍ 、曲げ強度が７８０ｋｇｆ／ｃｍ２の等方性黒鉛（東洋炭素（株）製) を、図４に示す形状を有するルツボに加工し、溶融金属と接するルツボ内面に、実施例１と同様の手順により、ケイ化処理を行った試験用溶融金属用ルツボを得た。ケイ化部の厚みは３ｍｍであった。Ｂ４Ｃを含む最外表層部は８μｍであった。また、ケイ化部の浅い所のケイ化率と深い所のケイ化率の比は、０．８であった。
【００６６】
（比較例４）
参考例２と同一材質の等方性黒鉛（東洋炭素（株）製）を使用し、図４に示す形状に加工し、試験用溶融金属用ルツボを得た。
【００６７】
前記参考例２及び比較例４で得られた試験用溶融金属用ルツボを用いて、鉄を溶解し、溶融試験を行った。
【００６８】
（参考例３）
炭素基材として、嵩密度１．９０ｇ／ｃｍ３ 、平均細孔半径が０．２μｍ、曲げ強度が９５０ｋｇｆ／ｃｍ２ の等方性黒鉛（東洋炭素（株）製）を、図５に示す形状に加工し、全面にわたり参考例１と同様の手順により、ケイ化処理を行った試験用ガラス搬送用ローラーを得た。ケイ化部の厚みは１ｍｍであった。Ｂ４Ｃを含む最外表層部は１０μｍであった。
【００６９】
（比較例５）
参考例３と同一材質の等方性黒鉛（東洋炭素（株）製）を使用し、図５に示す形状に加工し、試験用ガラス管搬送用ローラーを得た。
【００７０】
（参考例４）
炭素基材として、嵩密度１．８２ｇ／ｃｍ３ 、平均細孔半径が１．５μｍ 、曲げ強度が５５０ｋｇｆ／ｃｍ２、熱伝導率１２０ｋｃａｌ／ｈｍ ℃の等方性黒鉛（東洋炭素（株）製）を、図６に示すような外径４０ｍｍ、肉厚５ｍｍの管状に加工し、その全面に実施例１と同様の手順により、ケイ化処理を行った試験用鋼線材焼鈍用均熱管を得た。ケイ化部の厚みは２ｍｍであった。
【００７１】
（比較例６）
参考例４と同一材質の等方性黒鉛基材（東洋炭素（株）製）を使用し、参考例１と同様に、図６に示すような外径４０ｍｍ、肉厚５ｍｍの管状に加工し、試験用鋼線材焼鈍用均熱管を得た。
【００７２】
（実施例３）
高温焼成用治具の一例として、焼成炉用棚板を例にとり、高温焼成用治具について説明する。炭素基材として、嵩密度１．７７ｇ／ｃｍ３、平均細孔半径が１．５μｍ、曲げ強度が４００ｋｇｆ／ｃｍ２の等方性黒鉛（東洋炭素（株）製）を、４５０×３５０×４．０ｍｍの形状に加工し、全面にわたり実施例１と同様の手順により、ケイ化処理を行い、試験用焼成炉用棚板を得た。ケイ化部の厚みは２．０ｍｍであった。Ｂ４Ｃを含む最外表層部は１０μｍであった。
【００７３】
（比較例７）
実施例３と同一材質の等方性黒鉛（東洋炭素（株）製）を使用し、実施例３と同形状に加工し、試験用焼成炉用棚板を得た。
【００７４】
（参考例５）
炭素基材として、嵩密度１．８５ｇ／ｃｍ３ 、平均細孔半径が１．７μｍ、曲げ強度が５３０ｋｇｆ／ｃｍ２ 、熱伝導率１１０ｋｃａｌ／ｈｍ ℃の等方性黒鉛（東洋炭素（株）製）を、図７に示す形状を有するホットプレス用ダイスおよびパンチに加工し、実施例１と同様の手順により、ケイ化処理を行った試験用ホットプレス用ダイスを得た。ケイ化部の厚みは３．０ｍｍであった。Ｂ４Ｃを含む最外表層部は１０μｍであった。
【００７５】
（比較例８）
参考例５と同一材質、同一形状の等方性黒鉛基材（東洋炭素（株）製）を使用し、試験用ホットプレス用ダイスを得た。
【００７６】
上記実施例１〜３、参考例１〜５及び比較例１〜８で得られた各試験用製品をそれぞれの用途に適した試験を行った。試験結果を表１に示す。
【００７７】
【表１】
表１からも明らかなように、実施例１〜３、参考例１〜５は、比較例１〜８のものに対して良好な製品を長時間製造するに耐えうることができるものである。
【００７９】
【発明の効果】
請求項１〜３記載の本発明は、炭素質基材、最外表層部に厚みが１〜５０μｍである炭化ホウ素−炭化ケイ素−複合炭素層、ＳｉＣ含有複合層に厚みが１ｍｍ以上である炭化ケイ素含有層が形成されてなる耐酸化性の炭化ホウ素ー炭化ケイ素複合炭素材料を形成することを基本とするものであり、従来のＣＶＤ法、転化法、焼結法等とは異なり、比較的容易に炭素質基材の表層部の任意の場所や全体に形成でき、ＣＶＤ法により得られる被覆層と同等の緻密な、耐酸化性に優れたＢ４Ｃ−ＳｉＣ複合炭素材料とすることができる。また、本発明のＢ４Ｃ−ＳｉＣ複合炭素材料は、上記最外表層部のＳｉＣ／Ｂ４Ｃ比（重量％）を、ＳｉＣ／Ｂ4 Ｃ＝７８〜９７／３〜２２に設定したものであり、深さ方向に均一な層を形成できる。従って、上記の効果を経済性を考慮しつつ確実に発揮させることができる。
【００８０】
また、請求項４記載の発明は、本発明に係るＢ4 Ｃ−ＳｉＣ複合炭素材料を、焼結用ルツボの外面に形成させることにより、ルツボ外表面をがす不透過性の酸化保護皮膜で被覆し、ルツボ自身の寿命を伸ばすとともに、ルツボ外部からの不純物ガスの侵入を防ぎ、ルツボ内部の焼結用金属の純度を維持する効果を得ることができる。。
【００８１】
また、請求項５記載の発明は、本発明に係るＢ4 Ｃ−ＳｉＣ複合炭素材料を、真空蒸着用ルツボとして、ルツボ内面に形成させることにより、耐酸化性が向上し、ルツボ内の蒸着用溶融金属との反応を抑制することが可能となり、寿命の延命化を図ることができる。
【００８６】
また、請求項６記載の発明は、本発明に係るＢ４Ｃ−ＳｉＣ複合炭素材料を、高温焼成用治具、例えば、金属ロウ付け用治具や、焼成炉用棚板等の高温雰囲気下で使用される熱処理用治具の全面に形成させることにより、処理品への浸炭を抑制するとともに、治具の経時形状変化が抑制でき、処理品の製品寸法精度が一定に確保する事が可能となる。
【図面の簡単な説明】
【図１】実施例で使用した焼結用ルツボの概略図である。
【図２】実施例で使用した真空蒸着用ルツボの概略図である。
【図３】実施例で使用した連続鋳造用ダイスの概略斜視図である。
【図４】実施例で使用した金属溶融用ルツボの概略図である。
【図５】実施例で使用したガラス管搬送用ローラーの概略図である。
【図６】実施例で使用した鋼線材焼鈍用均熱管の概略図である。
【図７】実施例で使用したホットプレス用治具の概略図である。
【符号の説明】
１ 焼結用ルツボ
１１ 真空蒸着用ルツボ
２１ 連続鋳造用ダイス
３１ 金属溶融用ルツボ
４１ ガラス管搬送用ローラー
５２ 鋼線材焼鈍用均熱管
６１ ホットプレス用ダイス[0001]
BACKGROUND OF THE INVENTION
The present invention is a boron carbide-silicon carbide composite carbon material (hereinafter referred to as B) having excellent oxidation resistance that can be used in a high temperature atmosphere.FourC-SiC composite carbon material), and crucible for sintering and vacuum deposition using the sameas well asHigh temperature firing treatmentIngredientsRelated.
[0002]
[Prior art]
Carbon materials have excellent thermal conductivity, wear resistance, chemical resistance, and mechanical properties at high temperatures, so a high-purity treated carbon substrate alone can be used for sintering crucibles and vacuum deposition. It is widely used for crucibles for casting, dies for continuous casting, crucibles for molten metal, rollers for conveying glass tubes, soaking tubes for annealing steel wires, high-temperature firing jigs, hot pressing jigs, etc. However, there is a problem such as short life due to deterioration of strength and accuracy due to oxidation consumption.
[0003]
For the above problems, it is considered effective to coat the surface of the carbon substrate with silicon carbide (hereinafter referred to as SiC) having excellent oxidation resistance and compatibility with carbon. A vapor deposition method (CVD method), a conversion method (CVR method), and the like are well known.
[0004]
The SiC layer formed by the CVD method is very dense and has excellent gas impermeability and is effective in improving oxidation resistance, but is physically attached to the surface of the carbon substrate. In addition, since the coefficient of thermal expansion is different from that of the carbon base material, there is a drawback in that peeling of the layer and microcracks occur when subjected to thermal shock. Therefore, a carbon base material having a thermal expansion coefficient close to that of SiC must be used. In addition, due to the manufacturing method, there is a problem that it is difficult to cover partially or uniformly cover the inside of the hole, which increases the manufacturing cost.
[0005]
On the other hand, the CVR method is a method in which Si or SiO gas is reacted with a carbon substrate to convert the surface layer portion or the whole of the substrate into SiC. Unlike the CVD method, the SiC layer is chemically formed. Problems such as peeling off of the SiC layer are solved, but it also has the problem that it is subjected to denseness due to its manufacturing method, is not very effective in improving oxidation resistance, and is expensive as in the CVD method. Yes.
[0006]
The present invention has been made in view of the above-described problems, and the object of the present invention is to provide a simple method with excellent oxidation resistance and wear resistance, and a denser method compared to the CVD method and the CVR method. The SiC layer is economically formed on a predetermined portion (entire surface or part) of the surface layer portion of the carbon base material.FourC-SiC composite carbon material, crucible for sintering using the same, and crucible for vacuum depositionas well asHigh temperature firing treatmentIngredientsIt is a point to provide.
[0007]
[Means for Solving the Problems]
The present inventors previously applied Si powder, B on the surface of the carbonaceous substrate.FourA slurry containing C powder, a thermoplastic resin, and a solvent for the resin is applied, dried, and then heat-treated at 1500 ° C. or higher in a non-oxidizing atmosphere, thereby being dense and excellent in oxidation resistance and wear resistance. New BFourA C-SiC composite carbon material and a production method have been proposed (see JP-A-7-144882). As a result of trial and error, the present inventors have found a specific composition ratio and thickness of each layer necessary for having excellent oxidation resistance and wear resistance, and have completed the present invention. .
[0008]
The invention of claim 1 has a SiC-containing composite layer having a thickness of 1 mm or more at a predetermined portion (whole or a part) of the surface layer portion of the carbon substrate, and has a thickness of 1 to 50 μm on the SiC composite layer. BFourAn outermost surface layer containing C-SiC is not formed.The composition ratio (wt%) of the two components of boron carbide and silicon carbide of the boron carbide-silicon carbide-containing composite layer is silicon carbide / boron carbide = 78 to 97 / 3-22.This is an oxidation-resistant boron carbide-silicon carbide composite carbon material.
[0009]
The invention of claim 2 is the invention according to claim 1,Metallic Si is not present on the surface of the carbonaceous substrate.The boron carbide-silicon carbide composite carbon material according to claim 1.
[0010]
The invention according to
[0011]
Invention of Claim 4 is a crucible for sintering formed using a part or all of the surface layer part of the composite carbon material as described in any one of Claims 1-3.
[0012]
The invention of claim 5 is a crucible for vacuum vapor deposition that uses part or all of the surface layer portion of the composite carbon material according to any one of claims 1 to 3.
[0017]
Claim6The present invention is a high-temperature firing jig formed by using the composite carbon material according to any one of claims 1 to 3 for part or all of the surface layer portion.
[0019]
B of the present inventionFourThe outermost surface layer portion related to the C—SiC composite carbon material has at least BFourThe C component needs to be included, and it is not necessarily distributed in a state of being homogeneously mixed with SiC mixed in the surroundings. This outermost surface BFourC is easily oxidized and B in a high temperature oxidizing atmosphere2 OThreeForming a glassy B2 OThreeAs a result, the eutectic temperature with Si decreases, and finally SiO 22-B2 OThreeA vitreous system is formed, and this glass further coats the outermost surface layer to form a dense oxidation protective film. Therefore, a dense oxidation protective film excellent in gas impermeability is formed on the outermost layer.
[0020]
If the outermost surface layer portion having such a function is too thick, cracks and chips are likely to occur. Therefore, the outermost surface layer portion is formed to have a thickness of 3 to 20 μm, preferably 5 to 15 μm. By setting the thickness of the outermost surface layer in this way,2 OThreeWhile fully exhibiting the effect of oxidation resistance due to the above, it is possible to eliminate the waste of the manufacturing cost required for forming the outermost surface layer portion more than necessary and prevent the product cost from rising.
[0021]
SiC and BFourAs the composition ratio of C, SiC component is 78 to 99% by weight, BFourWhat C component is 1-22 weight% is desirable. Binary composition in this range (SiC, BFourB in which oxidation resistance is most efficiently imparted when a SiC layer having an outermost surface portion including C) is formedFourIt is because it can be set as a C-SiC composite carbon material. Furthermore, BFourC is preferably 3 to 20% by weight. In order to promote the formation of the SiC-containing composite layer, the lower limit is preferably 3% by weight or more, and when the outermost surface layer portion is oxidized at a high temperature, the outermost surface layer portion has SiO 22─B2 OThreeB that only forms a vitreous systemFourIt is sufficient if C is present, and considering this point, the upper limit is preferably 20% by weight or less.
[0022]
The SiC-containing composite layer following the outermost surface layer portion described above needs to contain at least SiC. This SiC-containing composite layer imparts oxidation resistance. Temporarily, the outermost surface layer SiO2─B2 OThreeEven when the glassy oxidation protective film is removed, the oxidation of the carbonaceous substrate is suppressed by the SiC of the SiC-containing composite layer. Therefore, the SiC-containing composite layer having such a function needs to have a thickness of 1 mm or more, and the SiC-C layer formed with a thickness of 1 mm or more can be formed substantially uniformly in the thickness direction. desirable. This is because the oxidation resistance in the thickness direction does not change. Here, “substantially uniform in the thickness direction” means that the ratio of the silicidation rate at the shallow portion and the silicidation rate at the deep portion of the SiC-containing composite layer is within 0.8.
[0023]
Such a deep and uniform SiC layer can be easily formed for the following reason. B contained in the outermost layer surfaceFourC does not penetrate into the inside of the base material, and has a function to permeate Si into the carbon base material by some action, for example, catalytic action. As a result, Si diffuses into the carbon base material by 1 mm or more in the depth direction. And it can be set as the state by which the SiC layer which has a uniform thickness of 1 mm or more was formed in the SiC containing composite layer.
[0024]
The carbon substrate used in the present invention is not particularly limited, and examples thereof include a carbon material substantially composed of only carbon, or a graphitized product containing carbon as a main component, such as a high-density isotropic graphite material. Of these carbon substrates, it is desirable to use a carbon substrate having an average pore radius measured by mercury porosimetry of 1 μm or more and processed into a product shape.
[0025]
When a carbon substrate having an average pore radius smaller than 1 μm is used, Si and BFourWhen the slurry mixed with C is applied to the carbon substrate, it is less desirable because the slurry hardly penetrates into the micropores of the carbon substrate. In addition, there is no restriction | limiting in particular about the upper limit of the average pore radius of a carbon base material, Since a carbon base material with a large average pore radius, such as a carbon fiber reinforced carbon composite material, the slurry penetrates deep inside the carbon base material. After heat treatment, the whole becomes a composite.
[0026]
First, Si powder having an average particle diameter of 10 to 100 μm, B having an average particle diameter of 5 to 100 μmFourA slurry comprising C powder, a thermoplastic resin and a solvent for the resin is prepared. As the thermoplastic resin used here, a resin having a high film forming property and a low residual carbon ratio is used. For example, a resin selected from polyamide imide, polyvinyl alcohol, and polyamide resin is particularly preferable. Of these, polyamide is more preferable, and it is used by dissolving in a solvent such as dimethylacetamide, dimethylformamide, dimethylsulfoxide, N-methyl-2-pyrrolidone.
[0027]
However, if a resin having a high residual carbon ratio, for example, a thermosetting resin such as furfuryl alcohol or phenol resin is used as the resin, the resin carbide or Si on the surface of the carbon substrate when high-temperature heat treatment is performed in a later step. And BFourThe reaction product with C is not preferable because it may be fixed and cannot be easily removed.
[0028]
Si powder and BFourThe mixing ratio when mixing C powder is B to Si powder 80-97 wt%.Four3 to 20% by weight of C powder is desirable. BFourWhen the C powder is less than 3% by weight,FourThis is because the effect of mixing the C powder is small. Specifically, BFourBy mixing C powder, BFourSome action by C, for example, a catalytic action effect appears. That is, when the amount is less than 3% by weight, this effect is not so manifested, and even after high-temperature heat treatment, molten Si does not completely penetrate into the pores in the carbon base material, and after cooling it is fixed as metal Si on the carbon base material surface. It will remain. On the other hand, when 3 wt% or more is contained, molten Si penetrates deeply into the pores, the reaction with the carbon substrate proceeds, SiC is formed, and SiC is uniform in the depth direction with the thickness according to claim 1. This is because an effect that the layer is easily formed can be obtained.
[0029]
In this case, there is no residue as metal Si on the surface of the carbon substrate, and the used resin carbide, SiC, BFourAlthough the residue of the component of C remains, in this invention, it is B to such an extent that this residue can be left.FourSince it is sufficient to add C powder, BFourThe upper limit of C powder is preferably about 20% by weight. Of course, 20% or more B depending on the required specificationsFourIt is also possible to add a C powder to form a deeper SiC layer and to add a further improvement in oxidation resistance and an improvement in wear resistance and other characteristics.
[0030]
The slurry prepared as described above is applied to the entire surface or a necessary portion by an appropriate means such as brushing or spatula coating. Moreover, you may immerse in a slurry. The thickness applied at this time can be any thickness, but is preferably 1 to 2 mm from the surface of the carbon substrate. If it is less than 100 μm, the formation of the SiC layer becomes shallow, which is not preferable. Thereafter, the solvent is removed by drying from about 80 ° C. to 200 ° C. for 5 hours to completely cure the resin. The material thus obtained is heat-treated at a high temperature in a vacuum of 10 Torr or less. The heating rate is 400 ° C./hour, and the temperature is maintained at about 1600 to 1800 ° C. for 1 hour. The heating means is not particularly limited and may be performed by an appropriate means. By this operation, the Si component melts, penetrates into the pores of the carbon base material through the carbonized layer of the resin, and reacts with carbon to form SiC.
[0031]
After obtaining the above-described series of treatments, the surface layer portion of the carbon base material corresponding to the portion to which the slurry is applied is converted into a SiC layer,FourB having a structure in which a dense outermost surface layer portion containing C component is formedFourA C—SiC composite carbon material can be obtained.
[0032]
B consisting of such a structureFourIf the C-SiC composite carbon material is oxidized at a high temperature, the outermost surface layer portion is made of SiO.2─B2 OThreeA melt of the system glass is generated, and this melt enters and covers the outermost surface layer so as to fill the voids in the outermost surface layer portion, and a state in which an oxidation protection film is newly formed is formed. This oxidation protective film functions to suppress subsequent oxidation. As a result, it is possible to form a dense protective film excellent in gas impermeability similar to that of an SiC film obtained by the CVD method. Moreover, B according to the present inventionFourIn the case of the C—SiC composite carbon material, it is easy to form the SiC layer on a part or the whole of the surface portion of the carbon base material. As a result, the SiC layer having excellent oxide resistance can be formed at any predetermined site. A carbon composite material formed economically can be provided.
[0033]
In the following B according to the inventionFourA specific application example using the C—SiC composite carbon material will be described.
[0034]
First, an application example for a sintering crucible will be described. Conventionally, as for the carbon base material of the crucible for sintering, isotropic high-density graphite is mainly used in the reduction furnace, but when replacing the sintered product, the surface of the crucible is exposed to the atmosphere, Moisture in the atmosphere is adsorbed on the carbon substrate. In addition, a trace amount of water is generated in the reduction furnace due to the reaction between hydrogen gas and oxygen. There is a problem that these moisture and the like become oxidation sources, oxidize the carbon material, and the gas generated at that time reacts with the sintered product in the crucible and causes contamination of the processed product.
[0035]
B of the present inventionFourWhen the C—SiC composite carbon material is applied to all or a part of the surface of the sintering crucible, these problems can be solved. The sintering crucible 1 comprises a crucible 2 and an
[0036]
The
[0037]
Next, an application example for a vacuum evaporation crucible will be described. Conventionally, a crucible for vacuum deposition is usually made of a carbon material that has been repeatedly subjected to steps such as pitch impregnation and firing so that molten metal does not penetrate into the pores of the carbon substrate. For example, in the case of a metal that reacts with a carbon material such as aluminum, a treatment such as impregnation and firing is further performed with a solution of an inorganic material salt, but there is a problem that the reaction with the metal cannot be completely prevented.
[0038]
B of the present inventionFourWhen the C—SiC composite carbon material is applied to all or a part of the surface of the vacuum evaporation crucible, particularly to the inner surface, these problems can be solved. As shown in FIG. 2, the crucible 11 for vacuum deposition of the present invention has a bulk density of 1.90 g / cm as a carbon substrate.ThreeAs described above, isotropic graphite having a specific resistance of 1200 μΩcm or less is used, and after machining the graphite into the shape shown in the figure, the slurry according to the present invention is brushed on the crucible
[0039]
Next, an example of application to a continuous casting member will be described. As a member for continuous casting, a carbon base material with excellent physical properties such as high-temperature mechanical properties, thermal conductivity, and lubricity has been conventionally used, but the carbon base material alone is very easy to oxidize and wear resistance. However, there is a disadvantage that the life is very short, such as premature breakage due to strength deterioration due to oxidation consumption.
[0040]
B of the present inventionFourWhen the C-SiC composite carbon material is applied to all or a part of the surface of the continuous casting member, particularly to the casting surface, these problems can be solved. As shown in FIG. 3, the
[0041]
By the way, the surface immediately after the composite treatment is rougher than the surface of the carbon base material before the treatment, and when such a surface is used as a die, the cooled and solidified ingot is intermittently formed. This is because a large frictional force acts between the two during drawing, the inner surface of the die is damaged by the ingot, and the scratch is transferred to the ingot to roughen the ingot surface. Therefore, the inner surface of the continuous casting member is always mirror-finished. There is no special limitation as a means of mirror surface processing, For example, the wet polishing method by a dice abrasive grain is mentioned. In addition, the final polishing degree may be 0.75 μm or less in terms of JIS average surface roughness (Ra). In addition, if the thermal conductivity of the surface after mirror finishing (SiC conversion layer) is ensured to be approximately 50 kcal / hrm ° C., the cooling and solidification ability of the metal is sufficient.
[0042]
As described above, the member for continuous casting obtained in the present invention is a mirror-finished B after a SiC coating layer is deeply formed on the portion of the carbon base material in contact with the molten metal and the ingot.FourIn this structure, a C-SiC composite layer is provided. For this reason, the surface of the carbon substrate is BFourBy covering with the C—SiC composite layer, the improvement of oxidation resistance and wear resistance, which are the objects of the present invention, can be surely effective. As a result, the life of the continuous casting member can be further extended, and at the same time, an ingot having a smooth casting surface can be stably and reliably manufactured for a long time.
[0043]
Next, an example of application to a molten metal crucible will be described. Isotropic high-density graphite is often used as a carbon base for molten metal crucibles, but most of them are used in atmospheric pressure, so they are oxidized by the atmosphere or the inside of the crucible reacts with the molten metal. There are problems such as.
[0044]
B of the present invention4 When the C—SiC composite carbon material is applied to all or a part of the surface of the molten metal crucible, particularly to the inner surface, these problems can be solved. As shown in FIG., MeltA melting
[0045]
CB according to the inventionFourBy forming the C—SiC composite layer on the inner surface of the crucible, the reaction with the molten metal can be suppressed, and the life of the crucible can be extended.
[0046]
Next, an application example for the glass tube transfer roller will be described. Although cast iron was used for the glass tube transport roller, there were problems in that the glass tube as a product was scratched and the shaping accuracy due to oxidative degradation was reduced. Therefore, carbon materials have been used instead of cast iron for the purpose of preventing scratches on the products. However, carbon materials alone have problems such as strength deterioration due to oxidation consumption and deterioration of glass tube shaping accuracy. Therefore, a carbon material having excellent oxidation resistance is required.
[0047]
B of the present invention4 When the C-SiC composite carbon material is applied to all or a part of the surface of the roller for transporting the glass tube, particularly to the casting surface, these problems can be solved. As shown in FIG.,The lath
[0048]
B on the entire surfaceFourBy forming the C-SiC composite layer, oxidation of the surface layer by glass is suppressed, so that deterioration of shaping accuracy due to oxidation can be prevented and the life of the roller can be extended.
[0049]
Next, an example of application to a soaking tube for annealing steel wires will be described. In the process of annealing a steel wire, conventionally, the wire has been moved and processed in a soaking tube made of stainless steel alone with sliding. At that time, there are many problems that the product wire rod is damaged due to the welding of the stainless steel soaking tube and the wire, and as a preventive measure, the carbon tube is inserted into the stainless steel soaking tube to prevent the welding of the wire rod. However, in this case, problems such as oxidative consumption of the carbon tube and carburization of the wire material newly occur, and a material for a soaking tube for annealing the steel wire material is desired instead of the carbon material.
[0050]
B of the present inventionFourThe C—SiC composite carbon material is formed on the entire inner surface of the carbon tube inserted into the soaking tube for annealing the steel wire material. FIG. 6 shows a schematic cross-sectional view of an example of a soaking tube for annealing steel wires. B of the present inventionFourBy forming the C—SiC composite layer on the inner surface of the
[0051]
Next, an application example for a high-temperature firing jig will be described. The high-temperature firing jig is a jig used in a high-temperature atmosphere such as a baking furnace shelf plate or a metal brazing jig, and a graphite material or a stainless steel material has been used. However, as described above, when a graphite material is used in a high-temperature atmosphere, there are problems of oxidation and carburization of the treated surface. There were problems such as deterioration of product dimension accuracy.
[0052]
B of the present inventionFourA C-SiC composite material is formed in a portion in contact with the treatment surface in a high temperature atmosphere. As a result, the above problems can be solved, and it becomes possible to provide a high-temperature firing jig made of carbon that has no change in shape with time and has excellent oxidation resistance.
[0053]
Next, an application example to a hot pressing jig will be described. For dies used for hot pressing and jigs such as upper and lower punches, graphite is often used because of the excellent high temperature characteristics of graphite. In that case, in order to prevent welding with a processed product, it was necessary to apply a release agent to the jig surface. This mold release agent has caused impurities to be mixed into the processed product.
[0054]
Therefore, B of the present inventionFourBy forming the C-SiC composite material on the upper and lower punches and the die surface of the hot press, it is possible to prevent the surface from being oxidized and to reduce the amount of impurities on the treated surface, thereby minimizing the release agent. It can be suppressed. As shown in FIG. 7, the hot pressing jig includes an integrated or divided die 61 and upper and
[0055]
【Example】
Hereinafter, the present invention will be specifically described with reference to examples.
Example 1
As a carbon substrate, bulk density 1.77 g / cmThree The average pore radius is 1.5 μm and the bending strength is 400 kgf / cm.2 Isotropic graphite (manufactured by Toyo Tanso Co., Ltd.) was processed into a crucible having the shape shown in FIG. 1 and its upper lid. Moreover, 8% solution of polyvinyl alcohol (manufactured by Nippon Synthetic Sangyo Co., Ltd.) as a binder was used as a dispersion medium. Silicon powder (manufactured by Wako Pure Chemical Industries, Ltd., average particle size 40 μm) and boron carbide powder (manufactured by Kyoritsu Ceramics Co., Ltd., average particle size 20 μm) are mixed at a weight ratio of 80:20 and mixed and dispersed in a dispersion medium. To make a slurry.
[0056]
After applying this slurry to a predetermined portion of the crucible and the upper lid whose carbon base material is in direct contact with the atmosphere, the solvent is evaporated at 200 ° C. in a dryer, and a nitrogen gas atmosphere of 3 Torr Lower the temperature in a vacuum furnace to 1600 ° C in 4 hoursShiAfter holding for 1 hour, it was cooled and taken out. The thickness of the silicide portion was 3 mm. BFourThe outermost surface layer portion including C was 10 μm. Moreover, the ratio of the silicification rate in the shallow part of the silicification part to the silicification rate in the deep part was 0.8.
[0057]
(Comparative Example 1)
Isotropic graphite (manufactured by Toyo Tanso Co., Ltd.) made of the same material as in Example 1 was used and processed into the shape shown in FIG. 1 to obtain a sintering crucible for testing.
[0058]
Using the sintering crucible for test obtained in Example 1 and Comparative Example 1, a tungsten carbide sintering test was performed in a state where graphite powder and tungsten powder were mixed as a sintering metal.
[0059]
(Example 2)
As a carbon substrate, bulk density of 1.9 g / cmThreeThe average pore radius is 0.4 μm and the bending strength is 650 kgf / cm.2The isotropic graphite (made by Toyo Tanso Co., Ltd.) having a specific resistance of 1200 μΩcm or less is processed into a crucible having the shape shown in FIG. 2, and the same procedure as in Example 1 is applied to the crucible inner surface 6 in contact with the molten metal. A crucible for vacuum deposition for test which was silicified was obtained. The thickness of the silicide portion was 2 mm. BFourThe outermost surface layer portion including C was 8 μm. Moreover, the ratio of the silicification rate in the shallow part of the silicification part to the silicification rate in the deep part was 0.8.
[0060]
(Comparative Example 2)
An isotropic graphite (manufactured by Toyo Tanso Co., Ltd.) made of the same material as in Example 2 was used and processed into the shape shown in FIG. 2 to obtain a test vacuum deposition crucible.
[0061]
Using the crucible for test vacuum deposition obtained in Example 2 and Comparative Example 2, aluminum was used as the molten metal for deposition, and a vacuum deposition test was performed.
[0062]
(referenceExample1)
As a carbon substrate, bulk density 1.87 g / cmThreeThe average pore radius is 1.5 μm and the bending strength is 650 kgf / cm.2Then, isotropic graphite (manufactured by Toyo Tanso Co., Ltd.) having a thermal conductivity of 120 kcal / hm ° C. was processed into a square die having the shape shown in FIG. 3, and the cast surface was silicified by the same procedure as in Example 1. A processed continuous casting die was obtained. The thickness of the silicide portion was 2 mm. The surface was polished to Ra = 0.75 μm using an abrasive to obtain a test continuous casting die.
[0063]
(Comparative Example 3)
referenceExample1Isotropic graphite substrate (made by Toyo Tanso Co., Ltd.) with the same material and shape asreferenceExample1A continuous casting die for test was obtained by performing the same polishing treatment.
[0064]
SaidreferenceExample1Using the crucible for test continuous casting obtained in Comparative Example 3, a continuous casting test was performed using a copper alloy.
[0065]
(referenceExample2)
As a carbon substrate, bulk density 1.82 g / cm3 The average pore radius is 1 μm and the bending strength is 780 kgf / cm.2Isotropic graphite (manufactured by Toyo Tanso Co., Ltd.) was processed into a crucible having the shape shown in FIG. 4, and a silicidation treatment was performed on the inner surface of the crucible in contact with the molten metal by the same procedure as in Example 1. A molten metal crucible for test was obtained. The thickness of the silicide portion was 3 mm. B4The outermost surface layer portion including C was 8 μm. Moreover, the ratio of the silicification rate in the shallow part of the silicification part to the silicification rate in the deep part was 0.8.
[0066]
(Comparative Example 4)
referenceExample2Isotropic graphite (manufactured by Toyo Tanso Co., Ltd.) and processed into the shape shown in FIG. 4 to obtain a molten metal crucible for testing.
[0067]
SaidreferenceExample2And using the crucible for molten metal for test obtained in Comparative Example 4, iron was melted and a melting test was performed.
[0068]
(referenceExample3)
As a carbon substrate, bulk density 1.90 g / cm3 The average pore radius is 0.2 μm and the bending strength is 950 kgf / cm.2 Isotropic graphite (Toyo Tanso Co., Ltd.) processed into the shape shown in FIG.referenceBy the same procedure as in Example 1, a test glass transport roller subjected to silicification was obtained. The thickness of the silicide portion was 1 mm. B4The outermost surface layer portion including C was 10 μm.
[0069]
(Comparative Example 5)
referenceExample3Isotropic graphite (manufactured by Toyo Tanso Co., Ltd.) and processed into the shape shown in FIG. 5 to obtain a glass tube transport roller for testing.
[0070]
(referenceExample4)
As a carbon substrate, bulk density 1.82 g / cm3 The average pore radius is 1.5 μm and the bending strength is 550 kgf / cm.2An isotropic graphite (made by Toyo Tanso Co., Ltd.) having a thermal conductivity of 120 kcal / hm ° C. was processed into a tube having an outer diameter of 40 mm and a wall thickness of 5 mm as shown in FIG. According to the procedure, a soaking tube for annealing a test steel wire material subjected to silicification was obtained. The thickness of the silicide portion was 2 mm.
[0071]
(Comparative Example 6)
referenceExample4Isotropic graphite base material (manufactured by Toyo Tanso Co., Ltd.)referenceExample1In the same manner as above, the tube was processed into a tube having an outer diameter of 40 mm and a wall thickness of 5 mm as shown in FIG.
[0072]
(Example3)
As an example of a high-temperature firing jig, a high-temperature firing jig will be described using a shelf plate for a firing furnace as an example. As a carbon substrate, bulk density 1.77 g / cm3The average pore radius is 1.5 μm and the bending strength is 400 kgf / cm.2Isotropic graphite (manufactured by Toyo Tanso Co., Ltd.) is processed into a shape of 450 × 350 × 4.0 mm, and silicidation is performed over the entire surface by the same procedure as in Example 1 for the test firing furnace. I got a shelf. The thickness of the silicide portion was 2.0 mm. B4The outermost surface layer portion including C was 10 μm.
[0073]
(Comparative Example 7)
Example3Using isotropic graphite (made by Toyo Tanso Co., Ltd.)3Were processed into the same shape as above to obtain a shelf for a test firing furnace.
[0074]
(referenceExample5)
As a carbon substrate, bulk density 1.85 g / cm3 The average pore radius is 1.7 μm and the bending strength is 530 kgf / cm.2 An isotropic graphite (manufactured by Toyo Tanso Co., Ltd.) having a thermal conductivity of 110 kcal / hm ° C. was processed into a hot press die and punch having the shape shown in FIG. A hot press die for testing was obtained. The thickness of the silicide part was 3.0 mm. B4The outermost surface layer portion including C was 10 μm.
[0075]
(Comparative Example 8)
referenceExample5A hot press die for testing was obtained using an isotropic graphite substrate (manufactured by Toyo Tanso Co., Ltd.) having the same material and shape as those of the above.
[0076]
Example 1 to above3, Reference Examples 1-5And each test product obtained in Comparative Examples 1 to 8 was subjected to a test suitable for each application. The test results are shown in Table 1.
[0077]
[Table 1]
As is clear from Table 1, Examples 1 to3, Reference Examples 1-5Can withstand the manufacture of a good product for a long time with respect to those of Comparative Examples 1-8.
[0079]
【The invention's effect】
The present invention described in claims 1 to 3 is a carbonaceous substrate, a boron carbide-silicon carbide-composite carbon layer having a thickness of 1 to 50 μm in the outermost surface layer portion, and a carbonization having a thickness of 1 mm or more in the SiC-containing composite layer. It is based on forming an oxidation-resistant boron carbide-silicon carbide composite carbon material in which a silicon-containing layer is formed. Unlike conventional CVD methods, conversion methods, sintering methods, etc., B, which can be easily formed on any part of the surface layer of the carbonaceous substrate or the entire surface, and is dense and excellent in oxidation resistance equivalent to a coating layer obtained by the CVD method.4It can be set as a C-SiC composite carbon material. In addition, B of the present invention4C-SiC composite carbon material is SiC / B of the outermost surface layer part.4C ratio (% by weight) is calculated as SiC / B.FourC = 78-97/3It is set to ˜22, and a uniform layer can be formed in the depth direction. Therefore, the above effect can be surely exhibited while considering the economy.
[0080]
Further, the invention according to claim 4 is the B of the present invention.FourBy forming the C-SiC composite carbon material on the outer surface of the sintering crucible, the crucible outer surface is coated with an impermeable oxidation protective film, extending the life of the crucible itself and introducing impurities from the outside of the crucible. It is possible to obtain an effect of preventing gas intrusion and maintaining the purity of the sintering metal inside the crucible. .
[0081]
Further, the invention according to claim 5 is the B of the present invention.FourBy forming the C-SiC composite carbon material on the inner surface of the crucible as a vacuum deposition crucible, the oxidation resistance is improved and the reaction with the molten metal for vapor deposition in the crucible can be suppressed, thereby extending the life. Can be achieved.
[0086]
Claims6The invention described is B according to the present invention.4By forming the C-SiC composite carbon material on the entire surface of a high-temperature firing jig such as a metal brazing jig or a heat treatment jig used in a high-temperature atmosphere such as a baking furnace shelf, While suppressing carburization of the processed product, it is possible to suppress changes in the shape of the jig over time, and to ensure a constant product dimensional accuracy of the processed product.
[Brief description of the drawings]
FIG. 1 is a schematic view of a sintering crucible used in Examples.
FIG. 2 is a schematic view of a vacuum evaporation crucible used in Examples.
FIG. 3 is a schematic perspective view of a continuous casting die used in Examples.
FIG. 4 is a schematic view of a metal melting crucible used in Examples.
FIG. 5 is a schematic view of a glass tube transport roller used in Examples.
FIG. 6 is a schematic view of a soaking tube for annealing steel wires used in Examples.
FIG. 7 is a schematic view of a hot pressing jig used in Examples.
[Explanation of symbols]
1 Crucible for sintering
11 Crucible for vacuum deposition
21 Continuous casting dies
31 Crucible for melting metal
41 Glass tube roller
52 Soaking tube for annealing steel wire
61 Hot press dies
Claims (6)
前記炭化ケイ素含有複合層の上に厚み３〜２０μｍである炭化ホウ素ー炭化ケイ素含有複合層が形成されてなり、
前記炭化ホウ素−炭化ケイ素含有複合層の炭化ホウ素と炭化ケイ素の２成分についての組成比（重量％）が、炭化ケイ素／炭化ホウ素＝７８〜９７／３〜２２であることを特徴とする耐酸化性の炭化ホウ素−炭化ケイ素複合炭素材料。A silicon carbide-containing composite layer having a thickness of 1 mm or more is formed on the surface layer portion of the carbonaceous substrate,
Ri Na and a thickness 3~20μm boron carbide over the silicon carbide-containing composite layer is formed on the silicon carbide-containing composite layer,
The composition ratio (wt%) of the two components of boron carbide and silicon carbide in the boron carbide-silicon carbide-containing composite layer is silicon carbide / boron carbide = 78-97 / 3-22 . Boron carbide-silicon carbide composite carbon material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33590598A JP4166350B2 (en) | 1998-06-26 | 1998-11-26 | Oxidation-resistant boron carbide-silicon carbide composite carbon material, sintering crucible using the same, vacuum evaporation crucible, and high-temperature firing jig |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18026398 | 1998-06-26 | ||
| JP10-180263 | 1998-06-26 | ||
| JP33590598A JP4166350B2 (en) | 1998-06-26 | 1998-11-26 | Oxidation-resistant boron carbide-silicon carbide composite carbon material, sintering crucible using the same, vacuum evaporation crucible, and high-temperature firing jig |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000086374A JP2000086374A (en) | 2000-03-28 |
| JP4166350B2 true JP4166350B2 (en) | 2008-10-15 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33590598A Expired - Lifetime JP4166350B2 (en) | 1998-06-26 | 1998-11-26 | Oxidation-resistant boron carbide-silicon carbide composite carbon material, sintering crucible using the same, vacuum evaporation crucible, and high-temperature firing jig |
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| Country | Link |
|---|---|
| JP (1) | JP4166350B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009256153A (en) * | 2008-04-21 | 2009-11-05 | Bridgestone Corp | Method and apparatus for producing silicon carbide powder |
| CN106460172B (en) * | 2014-02-06 | 2019-01-15 | Kgt石墨科技有限公司 | For the protective layer for the PECVD boat being made of graphite |
| US11753347B2 (en) * | 2019-10-14 | 2023-09-12 | Corning Incorporated | Rapid forming of glass and ceramics |
| CN113816755B (en) * | 2021-10-14 | 2023-09-01 | 西安鑫垚陶瓷复合材料有限公司 | Two-dimensional silicon carbide/silicon carbide composite bar and preparation method of connecting piece |
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1998
- 1998-11-26 JP JP33590598A patent/JP4166350B2/en not_active Expired - Lifetime
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| JP2000086374A (en) | 2000-03-28 |
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