JPH08119741A - Carbon-boron carbide sintered compact and carbon-boron carbide-silicon carbide sintered compact - Google Patents
Carbon-boron carbide sintered compact and carbon-boron carbide-silicon carbide sintered compactInfo
- Publication number
- JPH08119741A JPH08119741A JP6288549A JP28854994A JPH08119741A JP H08119741 A JPH08119741 A JP H08119741A JP 6288549 A JP6288549 A JP 6288549A JP 28854994 A JP28854994 A JP 28854994A JP H08119741 A JPH08119741 A JP H08119741A
- Authority
- JP
- Japan
- Prior art keywords
- carbon
- sintered body
- boron
- boron carbide
- sintered compact
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、耐酸化性を要求される
炉内部材や治具として好適な炭素−炭化ホウ素焼結体又
は炭素−炭化ホウ素−炭化ケイ素焼結体に関する。さら
に詳しく言えば、加熱ヒータ、金属溶解用ルツボ、熱電
対保護管、連続鋳造用鋳型やダイス、溶解金属かくはん
ロータ用部品、焼結用トレー、軸受けなどの各種の電気
・電子用部材、化学工業用部材、セラミック製造用部
材、機械用部材等（以下、炉内部材や治具と言う）に好
適に使用可能な材料に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon-boron carbide sintered body or a carbon-boron carbide-silicon carbide sintered body suitable as a furnace member or jig which is required to have oxidation resistance. More specifically, heaters, crucibles for melting metal, thermocouple protection tubes, casting molds and dies for continuous casting, parts for molten metal stirring rotors, sintering trays, bearings, and other various electrical and electronic parts, chemical industry. The present invention relates to a material that can be suitably used as a member for ceramics, a member for producing ceramics, a member for machinery (hereinafter referred to as a member in a furnace or a jig).
【０００２】[0002]
【従来の技術】炭素材料は耐熱性、耐薬品性、良電気伝
導性、低熱膨張率、軽量であるなど優れた性質を持つた
め、産業界の広い分野で使用されている。ところが、高
温の空気中では酸化消耗を受け易いという欠点を有する
ため、炭素材料の耐酸化性を改善させる方法が色々提案
されてきた。2. Description of the Related Art Carbon materials have excellent properties such as heat resistance, chemical resistance, good electrical conductivity, low coefficient of thermal expansion, and light weight, and are therefore used in a wide range of industrial fields. However, since it has a drawback that it is susceptible to oxidative consumption in high temperature air, various methods for improving the oxidation resistance of carbon materials have been proposed.
【０００３】例えばＣＶＤ（化学蒸着）法により、炭素
材料を基体とし、その表面にち密質の炭化ケイ素を被覆
する方法が提案されている。この炭化ケイ素被覆炭素材
料は、優れた不浸透性を有しているものの、被膜と炭素
基体との界面が分離しているため、熱衝撃を受けると被
膜のはく離が生じ易いという欠点があった。また、炭素
基体の表層部に炭化ケイ素や炭化ホウ素層を形成させる
方法として、転化（コンバージョン）法が知られてい
る。この方法は、ケイ素ガスや一酸化ケイ素ガス又は酸
化ホウ素ガス等を炭素基体に反応させて、基体の表層部
を炭化ケイ素や炭化ホウ素層に転化する方法であり、炭
素基体と転化層との間で、層間はく離を生じにくくなっ
ている。しかし、ＣＶＤ法に比較してち密性に劣るた
め、酸素の侵入を完全に防ぐことができず、満足に使用
できる材料ではなかった。また、リン酸化合物溶液など
を炭素基体に含浸する、いわゆる含浸処理法も知られて
いるが、この方法でも含浸ムラ等が発生し、十分な耐酸
化性を得られなかった。For example, a method has been proposed in which a carbon material is used as a substrate and its surface is coated with dense silicon carbide by, for example, the CVD (chemical vapor deposition) method. Although this silicon carbide-coated carbon material has excellent impermeability, the interface between the coating and the carbon substrate is separated, so that there is a drawback in that the coating is likely to peel when it is subjected to thermal shock. . A conversion method is known as a method for forming a silicon carbide or boron carbide layer on the surface layer of a carbon substrate. This method is a method in which a silicon gas, a silicon monoxide gas, a boron oxide gas, or the like is reacted with a carbon substrate to convert the surface layer portion of the substrate into a silicon carbide or boron carbide layer, and between the carbon substrate and the conversion layer. Therefore, delamination is less likely to occur. However, since it is less dense than the CVD method, it is not possible to completely prevent the invasion of oxygen, and the material cannot be used satisfactorily. There is also known a so-called impregnation treatment method of impregnating a carbon substrate with a phosphoric acid compound solution or the like, but even in this method, impregnation unevenness or the like occurs and sufficient oxidation resistance cannot be obtained.
【０００４】そこで、炭化ホウ素（Ｂ４Ｃ）粉末と炭化
ケイ素（ＳｉＣ）粉末との混合物と生コークスとを混合
して焼結した材料（例えば、特開昭５９−１３１５７６
号公報）や、炭化ホウ素（Ｂ４Ｃ）とメソカーボンマイ
クロビーズ（メソフェーズ小球体ともいう）とを混合し
て焼結した材料（例えば、特開平１−１０００６３号公
報、特開平５−２４６７６１号公報）が提案されてお
り、高い耐酸化性を示している。これらの焼結体が高い
耐酸化性を示す理由は、焼結体中の炭化ホウ素や炭化ケ
イ素が酸化されると酸化ホウ素（Ｂ２Ｏ３）や酸化ケイ
素（ＳｉＯ２）を生じ、これがガラス状の酸化保護膜と
なって焼結体の全表面を被覆するため、焼結体の内部へ
の酸素の侵入を防ぐことにより、酸化を抑制するからで
ある。従来、これらの焼結体は、高い耐酸化性を有し、
ホウ素を多く含んでいることから、原子炉の中性子吸収
材や遮蔽材等の特殊な用途しか使用されていなかった。Therefore, a material obtained by mixing a mixture of boron carbide (B 4 C) powder and silicon carbide (SiC) powder and raw coke and sintering the mixture (for example, JP-A-59-131576).
Material) or a material obtained by mixing and sintering boron carbide (B 4 C) and mesocarbon microbeads (also referred to as mesophase microspheres) (for example, Japanese Patent Application Laid-Open Nos. 1-100063 and 5-246761). Gazette) has been proposed and shows high oxidation resistance. The reason why these sintered bodies exhibit high oxidation resistance is that when boron carbide or silicon carbide in the sintered body is oxidized, boron oxide (B 2 O 3 ) or silicon oxide (SiO 2 ) is produced, which is glass. This is because the surface of the sintered body is covered with the oxide-like protective film, and the oxidation is suppressed by preventing oxygen from entering the inside of the sintered body. Conventionally, these sintered bodies have high oxidation resistance,
Since it contains a large amount of boron, it has only been used for special applications such as neutron absorbers and shielding materials for nuclear reactors.
【０００５】かかる焼結体は、このような特殊用途に使
われることを前提として製造されており、耐酸化性の向
上、ホウ素の高濃度化及び高強度の追求のみを主な目的
としていたため、高密度化されたものになっていた。そ
の結果、必然的に気孔半径の小さい焼結体になってお
り、従来は、このような焼結体を炉内部材や治具に使用
していた。Since such a sintered body is manufactured on the assumption that it is used for such a special purpose, its main purpose is to improve the oxidation resistance, increase the concentration of boron, and pursue high strength. , It was densified. As a result, a sintered body having a small pore radius is inevitably formed, and conventionally, such a sintered body has been used as a furnace member or a jig.
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、これら
の焼結体の酸化保護膜の一つである酸化ホウ素（Ｂ２Ｏ
３）は、４００〜５００℃で溶融し、流動するため、か
かる焼結体を耐酸化性が要求される炉内部材や治具とし
て使用する場合には、その焼結体が接触している相手部
材との隙間を酸化ホウ素が埋めてしまい、両者を固着し
てしまうという問題があった。そのため、高い耐酸化性
を示しながら、炉内部材や治具としては実用化に至って
いなかった。However, boron oxide (B 2 O), which is one of the oxidation protection films for these sintered bodies, is used.
Since 3 ) melts and flows at 400 to 500 ° C., when such a sintered body is used as a furnace member or jig that requires oxidation resistance, the sintered body is in contact with it. There is a problem that boron oxide fills the gap with the mating member and fixes the two. Therefore, while showing high oxidation resistance, it has not been put into practical use as a furnace member or a jig.
【０００７】[0007]
【課題を解決するための手段】その対策として、本発明
者らは焼結体のホウ素含有濃度と気孔半径に着目した。
従来の焼結体の気孔半径を逆に大きくし、特定範囲のホ
ウ素濃度であれば、焼結体と相手部材との固着を防止で
きることを見いだしたのである。As a countermeasure, the present inventors have focused on the boron content concentration and the pore radius of the sintered body.
It has been found that, when the pore radius of the conventional sintered body is increased to the contrary and the boron concentration is within a specific range, it is possible to prevent the sintered body and the mating member from sticking to each other.
【０００８】すなわち本発明は、ホウ素含有濃度が５乃
至４０質量％であり、且つ、水銀圧入法による平均気孔
半径が０．１及至１０マイクロメータ（以下μｍと記
す）である炭素−炭化ホウ素焼結体又は炭素−炭化ホウ
素−炭化ケイ素焼結体にすることで、耐酸化性を有した
ままで、酸化ホウ素（Ｂ２Ｏ３）を表面付近の開気孔内
面にとどめ、焼結体と相手部材との固着を防止できる。That is, according to the present invention, a carbon-boron carbide calcination having a boron content of 5 to 40 mass% and an average pore radius of 0.1 to 10 micrometers (hereinafter referred to as μm) as determined by mercury porosimetry. By forming a sintered body or a carbon-boron carbide-silicon carbide sintered body, the boron oxide (B 2 O 3 ) is retained on the inner surface of the open pores near the surface while keeping the oxidation resistance, and the sintered body and the sintered body are mated with each other. It is possible to prevent sticking to the member.
【０００９】[0009]
【発明の構成】本発明に係る炭素−炭化ホウ素焼結体と
は、炭素及び炭化ホウ素から成る焼結体を意味し、炭素
−炭化ホウ素−炭化ケイ素焼結体とは、炭素、炭化ホウ
素及び炭化ケイ素から成る焼結体を意味する。The carbon-boron carbide sintered body according to the present invention means a sintered body composed of carbon and boron carbide, and the carbon-boron carbide-silicon carbide sintered body means carbon, boron carbide and It means a sintered body made of silicon carbide.
【００１０】具体的にその製造方法の代表例を挙げる
と、炭素−炭化ホウ素焼結体は、炭化ホウ素粉（以下、
Ｂとも略す）及び炭素粉（以下、Ｇとも略す）更には必
要に応じて炭化できる原料（以下、Ｐとも略す）を混合
し、成形、焼成工程を経て製造する方法である。炭素−
炭化ホウ素−炭化ケイ素焼結体は、炭化ホウ素粉
（Ｂ）、炭化ケイ素粉（以下、Ｓとも略す）及び炭素粉
（Ｇ）更には必要に応じて炭化できる原料（Ｐ）とを混
合し、成形、焼成工程を経て製造する方法である。以下
に、本発明に係る焼結体の代表的な製造方法を具体的に
示す。A typical example of the method for producing the carbon-boron carbide sintered body is a boron carbide powder (hereinafter,
This is a method in which a B powder), a carbon powder (hereinafter also abbreviated as G), and a raw material that can be carbonized (hereinafter also abbreviated as P) as needed are mixed, and the mixture is molded and fired. Carbon-
The boron carbide-silicon carbide sintered body is prepared by mixing boron carbide powder (B), silicon carbide powder (hereinafter also abbreviated as S), carbon powder (G) and, if necessary, a raw material (P) capable of being carbonized, It is a method of manufacturing through molding and firing steps. Hereinafter, a typical method for producing a sintered body according to the present invention will be specifically shown.
【００１１】炭化ホウ素粉（Ｂ）や炭化ケイ素粉（Ｓ）
は、市販のものでも良いが、平均粒径がサブミクロンの
炭化ホウ素粉（Ｂ）や炭化ケイ素粉（Ｓ）は非常に高価
であり、また、このような平均粒径の粉末は焼結性が良
過ぎてしまい、それに伴って気孔半径も小さくなるた
め、平均粒径は１μｍ以上のものが特に好ましい。一
方、炭化ホウ素粉（Ｂ）や炭化ケイ素（Ｓ）の平均粒径
が４０μｍを超えると、焼結体中のホウ素成分の偏在部
が大きくなる傾向があり、耐酸化性に悪影響を及ぼすこ
とがあるのであまり好ましくない。それ故、本発明にお
いては、炭化ホウ素粉（Ｂ）や炭化ケイ素粉（Ｓ）の平
均粒径は、１〜４０μｍ以下のものを使用した方が良
い。Boron carbide powder (B) and silicon carbide powder (S)
May be commercially available, but boron carbide powder (B) and silicon carbide powder (S) having an average particle size of submicron are very expensive, and powder having such an average particle size is sinterable. Is too good, and the pore radius becomes smaller accordingly, so that the average particle size is particularly preferably 1 μm or more. On the other hand, when the average particle size of the boron carbide powder (B) or silicon carbide (S) exceeds 40 μm, the uneven distribution of the boron component in the sintered body tends to increase, which may adversely affect the oxidation resistance. It is not so preferable because it exists. Therefore, in the present invention, it is preferable to use boron carbide powder (B) or silicon carbide powder (S) having an average particle size of 1 to 40 μm or less.
【００１２】炭素粉（Ｇ）は、一般に炭素材を製造する
ための骨材として使用されているものであれば良く、例
えばニードルコークス、ピッチコークス、フリュードコ
ークス、ギルソナイトコークス等の石油系や石炭系のか
焼された又はか焼されていない各種コークス粉、ＰＡＮ
系やピッチ系の各種炭素繊維粉、メソカーボンマイクロ
ビーズやバルクメソフェーズ等の各種メソフェーズカー
ボン粉、各種熱分解炭素粉、サーマルブラック、ファー
ネスブラック、ランプブラック、チャンネルブラック等
の各種カーボンブラック粉、各種ガラス状炭素粉、各種
人造黒鉛粉及び各種天然黒鉛粉などを用いることができ
る。平均粒径は、炭化ホウ素粉（Ｂ）や炭化ケイ素粉
（Ｓ）と同じ理由により、１〜４０μｍのものが特に好
適である。The carbon powder (G) may be any as long as it is generally used as an aggregate for producing a carbon material. For example, petroleum-based materials such as needle coke, pitch coke, flue coke, and Gilsonite coke, Various coal-based calcined or non-calcined coke powders, PAN
-Based and pitch-based carbon fiber powders, mesocarbon microbeads, bulk mesophase carbon powders, mesophase carbon powders, pyrolytic carbon powders, thermal blacks, furnace blacks, lamp blacks, channel blacks, and other carbon black powders, glass Carbon powder, various artificial graphite powders, various natural graphite powders and the like can be used. For the same reason as the boron carbide powder (B) and the silicon carbide powder (S), the average particle diameter is particularly preferably 1 to 40 μm.
【００１３】必要に応じて使用する炭化できる原料
（Ｐ）としては、ピッチ、タール類、芳香族多環式有機
化合物、合成樹脂（例えば、フェノール樹脂、フラン樹
脂、イミド樹脂、アミド樹脂等の高分子化合物、特に縮
合系高分子）や天然高分子等が具体的に挙げられる。こ
れらは、主として炭化ホウ素粉（Ｂ）や炭化ケイ素粉
（Ｓ）及び炭素粉（Ｇ）とを結合させるバインダー成分
として添加するものであるが、焼成時には炭化して炭素
粉（Ｇ）と渾然一体となり、最終的には焼結体の一成分
として機能する。炭化できる原料（Ｐ）は、主に炭素粉
（Ｇ）の持つ粘着性の有無によって、その使用の有無が
決定される。例えば炭素粉（Ｇ）としてメソカーボンマ
イクロビーズやいわゆる生コークスを用いた場合には、
それが持つ粘結成分により、この（Ｐ）を使用しなくて
も、成形することができる。しかし、炭素粉（Ｇ）とし
て、いわゆるか焼コークス粉を用いた場合には、粘結成
分をほとんど有していないため、これらだけでは固まら
ず、バインダー成分として炭化できる原料（Ｐ）を添加
する必要がある。The carbonizable raw material (P) used as required includes high pitch compounds such as pitch, tars, aromatic polycyclic organic compounds, synthetic resins (for example, phenol resin, furan resin, imide resin, amide resin, etc.). Specific examples thereof include molecular compounds, particularly condensed polymers) and natural polymers. These are mainly added as a binder component that binds the boron carbide powder (B), the silicon carbide powder (S) and the carbon powder (G), but they are carbonized during firing and naturally integrated with the carbon powder (G). And finally functions as a component of the sintered body. Whether or not the raw material (P) that can be carbonized is used is determined mainly by the presence or absence of tackiness of the carbon powder (G). For example, when mesocarbon microbeads or so-called raw coke is used as the carbon powder (G),
Owing to its caking component, it can be molded without using this (P). However, when so-called calcined coke powder is used as the carbon powder (G), since it has almost no caking component, the raw material (P) which does not solidify by itself and can be carbonized as a binder component is added. There is a need.
【００１４】各原料成分（Ｇ）、（Ｂ）、（Ｓ）及び必
要に応じ用いられる（Ｐ）の配合割合は、原則として、
熱処理時に発生するガスによって割れやふくれ等を生じ
ない配合割合であれば良く、通常は以下の通りである。
なお、炭化ホウ素粉（Ｂ）及び炭化ケイ素粉（Ｓ）の混
合粉を（ＢＳ）と略す。また、炭素原子とホウ素原子の
質量はほぼ等しく、炭化ホウ素粉の質量の約４／５に相
当する質量をホウ素の質量と推定できるので、焼結体中
のホウ素含有濃度は、炭化ホウ素粉（Ｂ）の配合割合に
よって簡単に調節することができる。As a general rule, the mixing ratios of the respective raw material components (G), (B), (S) and (P) used as necessary are
The compounding ratio may be any as long as it does not cause cracking, blistering, etc. due to the gas generated during the heat treatment, and is usually as follows.
The mixed powder of boron carbide powder (B) and silicon carbide powder (S) is abbreviated as (BS). Moreover, since the mass of carbon atoms and the mass of boron atoms are almost equal, and the mass corresponding to about 4/5 of the mass of boron carbide powder can be estimated as the mass of boron, the boron-containing concentration in the sintered body is It can be easily adjusted by the blending ratio of B).
【００１５】《炭素粉（Ｇ）が粘着性を有する場合》 （Ｇ） ５０〜９５質量％ （Ｂ）又は（ＢＳ） ５〜５０質量％ なお、この場合には炭素粉（Ｇ）０〜２０質量％を更に
添加しても良い。<< When carbon powder (G) has tackiness >> (G) 50 to 95% by mass (B) or (BS) 5 to 50% by mass In this case, carbon powder (G) 0 to 20 You may add mass% further.
【００１６】《炭素粉（Ｇ）が粘着性を有しない場合》 （Ｇ） ４０〜７０質量％ （Ｂ）又は（ＢＳ） ５〜３０質量％ （Ｐ） １５〜５０質量％<< When the carbon powder (G) has no tackiness >> (G) 40 to 70% by mass (B) or (BS) 5 to 30% by mass (P) 15 to 50% by mass
【００１７】しかしながら、いずれの場合でも、ホウ素
含有濃度が４０質量％を超えると焼結しにくくなって、
でき上がった焼結体の強度が急激に弱くなるため、炉内
部材や治具の形状に加工できなくなる。また、このよう
な高ホウ素濃度の焼結体は、平均気孔半径が０．１μｍ
未満になると相手部材と固着してしまうため、本発明に
は適当でない。一方、ホウ素含有濃度が５質量％未満で
は、でき上がった焼結体の耐酸化性が低くなり過ぎ、基
体が酸化されてしまう。特にこの酸化現象は、平均気孔
半径が１０μｍを超える焼結体では顕著に現れる。さら
に、平均気孔半径が１０μｍを超える焼結体の場合、機
械的強度が急激に低下し、表面から微粒子が脱離して炉
内や相手部材を汚染するため、炉内部材や治具としては
実用的でない。このような理由により、０．１〜１０μ
ｍの平均気孔半径を有する焼結体においては、ホウ素含
有濃度が５〜４０質量％でなければならない。However, in any case, if the boron content concentration exceeds 40% by mass, it becomes difficult to sinter,
Since the strength of the finished sintered body suddenly weakens, it becomes impossible to process it into the shape of a furnace member or a jig. Further, such a high boron concentration sintered body has an average pore radius of 0.1 μm.
If it is less than the above range, it will stick to the mating member and is not suitable for the present invention. On the other hand, if the boron content is less than 5% by mass, the oxidation resistance of the finished sintered body will be too low and the substrate will be oxidized. In particular, this oxidation phenomenon remarkably appears in the sintered body having an average pore radius of more than 10 μm. Further, in the case of a sintered body having an average pore radius of more than 10 μm, the mechanical strength is drastically reduced and fine particles are detached from the surface to contaminate the inside of the furnace or the other member, so that it is practically used as a member in the furnace or a jig Not relevant. For this reason, 0.1-10μ
In a sintered body with an average pore radius of m, the boron content should be 5-40% by weight.
【００１８】これらの各原料を、常法に従い、任意の有
効な装置により混合した後、昇温し、又は昇温しないで
成形する。These respective raw materials are mixed by an effective apparatus according to a conventional method and then heated or molded without heating.
【００１９】この際、成形圧力は（Ｇ）、（Ｂ）、
（Ｓ）及び必要に応じて用いられる（Ｐ）の配合割合に
よって適宜決めることができるが、成形圧力が０．４ｔ
ｏｎ／ｃｍ２（１０ＭＰａ）未満では、平均気孔半径が
大きくなり過ぎてしまい、１０μｍ以上になる場合があ
る。さらには、焼結体の強度が低くなり過ぎて、炉内部
材や治具の形状に加工できなくなる場合もある。一方、
成形圧力が２．０ｔｏｎ／ｃｍ２（２００ＭＰａ）を超
えると、焼結体の焼き締まりが進み、焼結体の平均気孔
半径が０．１μｍ未満になる場合もある。したがって、
成形圧力は０．４乃至２．０ｔｏｎ／ｃｍ２（１０〜２
００ＭＰａ）以下が好ましい。かかる成形は常法に従
い、例えば金型成形、静水圧加圧成形の方法で行えば良
い。At this time, the molding pressure is (G), (B),
It can be appropriately determined depending on the mixing ratio of (S) and (P) used as necessary, but the molding pressure is 0.4 t.
If it is less than on / cm 2 (10 MPa), the average pore radius may be too large, and may be 10 μm or more. Furthermore, the strength of the sintered body may become too low to be processed into the shape of the furnace member or jig. on the other hand,
If the molding pressure exceeds 2.0 ton / cm 2 (200 MPa), the sintering of the sintered body may proceed, and the average pore radius of the sintered body may become less than 0.1 μm. Therefore,
The molding pressure is 0.4 to 2.0 ton / cm 2 (10 to 2
00 MPa) or less is preferable. Such molding may be carried out according to a conventional method, for example, a method of molding using a die or a method of isostatic pressing.
【００２０】このようにして成形された成形体を加圧し
又は加圧しないで仮焼成（予備焼成ともいう）し、又は
仮焼成しないで、炭素粉（Ｇ）や炭化できる原料（Ｐ）
を炭化する。仮焼成温度は、通常６００〜１３００℃で
ある。次いで、有意な焼結炉により焼成して焼結体にす
ることができる。焼成温度は、通常１０００〜２８００
℃である。仮焼成や焼成は、常法に従い、例えばアルゴ
ンガス等の非酸化性雰囲気で行う。The thus-formed compact is calcined (also called preliminary calcining) with or without pressure, or carbon powder (G) or a raw material (P) that can be carbonized without calcining.
Carbonize. The calcination temperature is usually 600 to 1300 ° C. It can then be fired into a sintered body in a significant sintering furnace. The firing temperature is usually 1000-2800
° C. The calcination and the calcination are performed according to a conventional method, for example, in a non-oxidizing atmosphere such as argon gas.
【００２１】以上のように、原料粒径、成型圧力及び焼
成温度をいろいろ変化させることによって、平均粒径
０．１乃至１０μｍの焼結体を得ることができる。As described above, a sintered body having an average particle diameter of 0.1 to 10 μm can be obtained by variously changing the raw material particle diameter, the molding pressure and the firing temperature.
【００２２】得られた焼結体を所望の形状に加工して、
各種製品に仕上げる。この際、相手部材に接触する面
は、日本工業規格（ＪＩＳ）Ｂ０６０１で定義され、同
Ｂ０６５１に準拠して測定される中心線平均粗さＲａ
（以下、表面粗さＲａと言う）が１．６μｍ以上になる
ように加工した方が好ましい。なぜなら、炭化ホウ素の
酸化により生じた酸化ホウ素は、焼結体の表面にガラス
状の酸化保護膜として存在するわけだが、表面粗さＲａ
が１．６μｍ以上になると、焼結体が接触している相手
部材との空隙が多くなるため、より多くの酸化ホウ素を
焼結体の表面付近に蓄えることができ、より一層の固着
防止効果を奏するからである。また、かかる面の表面粗
さＲａが２５．０μｍを超えると、その表面から微粒子
が脱離して炉内や相手部材を汚染する原因になる。それ
故、相手部材に接触する焼結体の面は、表面粗さＲａが
１．６〜２５．０μｍになるように加工した方が良いの
である。これらの表面粗さＲａの規定は、溶融した酸化
ホウ素の粘度変化に伴い、８００℃以上に使用される炉
内部材や治具等には特に効果的である。一方、相手部材
の表面粗さも上記同様の理由により、相手部材の表面粗
さＲａが１．６μｍ以上の面に接触させるように焼結体
を取付けた方が良い。The obtained sintered body is processed into a desired shape,
Finish various products. At this time, the surface in contact with the mating member is defined by the Japanese Industrial Standard (JIS) B0601, and the center line average roughness Ra measured according to the same B0651.
It is preferable to process so that (hereinafter referred to as surface roughness Ra) is 1.6 μm or more. Because the boron oxide produced by the oxidation of boron carbide exists as a glass-like oxidation protective film on the surface of the sintered body, the surface roughness Ra
Is 1.6 μm or more, the number of voids between the sintered body and the mating member with which the sintered body is in contact increases, so that more boron oxide can be stored in the vicinity of the surface of the sintered body, and the effect of further preventing sticking is increased. Because it plays. Further, if the surface roughness Ra of such a surface exceeds 25.0 μm, fine particles are detached from the surface and cause contamination in the furnace or the mating member. Therefore, it is better to process the surface of the sintered body that contacts the mating member so that the surface roughness Ra is 1.6 to 25.0 μm. The regulation of the surface roughness Ra is particularly effective for the furnace members and jigs used at 800 ° C. or higher according to the change in viscosity of the molten boron oxide. On the other hand, for the reason that the surface roughness of the mating member is the same as above, it is better to mount the sintered body so as to contact the surface of the mating member having a surface roughness Ra of 1.6 μm or more.
【００２３】本発明においては、焼結体には本発明の目
的を阻害しない範囲であれば、形態を問わず他の元素や
化合物を含んでいても良く、例えば製造上不可避の不純
物元素Ｆｅ、Ｃａ、Ｖ、Ｎａ、Ａｌ、Ｎｉ、Ｐｂ、Ｃ
ｒ、Ｍｇ、Ｔｉ、Ｓ、Ｐ等やその化合物が含まれていて
も良い。In the present invention, the sintered body may contain other elements or compounds regardless of the form as long as the object of the present invention is not impaired. For example, the impurity element Fe which is unavoidable in manufacturing, Ca, V, Na, Al, Ni, Pb, C
r, Mg, Ti, S, P or the like or a compound thereof may be contained.
【００２４】[0024]
【作用】従来の焼結体の酸化保護膜である酸化ホウ素
（Ｂ２Ｏ３）は、焼結体の表面や表面付近の開気孔表面
に生成していた。しかしながら、本発明に係る焼結体
は、平均気孔半径を適度の大きさにしているため、酸化
ホウ素を表面付近の開気孔内面にとどめることができ、
焼結体と相手部材との固着を防止できる。ここで、炭素
−炭化ホウ素−炭化ケイ素焼結体の場合、炭化ケイ素は
酸化されると二酸化ケイ素（ＳｉＯ２）に変化して、酸
化ホウ素膜と同様に酸化保護膜の機能を果たすが、この
場合でも、平均気孔半径が０．１及至１０μｍの焼結体
であれば足りる。二酸化ケイ素の融点は約１８００℃で
あり、酸化ホウ素の融点に比べてかなり高温であるた
め、相手部材との固着原因にならないからと思われる。
すなわち、焼結体に炭化ケイ素が含まれていても、ホウ
素含有濃度と平均気孔半径とが特定の範囲内であれば、
相手部材に固着しないことが判明して、本発明を完成さ
せたのである。FUNCTION: Boron oxide (B 2 O 3 ) which is an oxidation protection film for a conventional sintered body is produced on the surface of the sintered body or on the surface of open pores near the surface. However, since the sintered body according to the present invention has an average pore radius of an appropriate size, boron oxide can be retained on the inner surface of the open pores near the surface,
It is possible to prevent the sintered body and the mating member from sticking to each other. Here, in the case of a carbon-boron carbide-silicon carbide sintered body, when silicon carbide is oxidized, it changes to silicon dioxide (SiO 2 ) and functions as an oxidation protection film like the boron oxide film. Even in this case, a sintered body having an average pore radius of 0.1 to 10 μm is sufficient. It is considered that silicon dioxide has a melting point of about 1800 ° C., which is considerably higher than the melting point of boron oxide, so that it does not cause sticking to the mating member.
That is, even if the sintered body contains silicon carbide, if the boron content concentration and the average pore radius are within a specific range,
The present invention was completed when it was found that they did not stick to the mating member.
【００２５】[0025]
【実施例】実施例により本発明を説明する。The present invention will be described with reference to examples.
【００２６】＜炭素−炭化ホウ素焼結体＞<Carbon-Boron Carbide Sintered Body>
【００２７】実施例１〜４、比較例１及び参考例１ コールタールピッチを加熱処理して生成したメソカーボ
ンマイクロビーズ（平均粒径２０μｍ）７０質量％、炭
化ホウ素粉（平均粒径１５μｍ）２０質量％及び人造黒
鉛粉（平均粒径１５μｍ）１０質量％とを配合して、常
圧で１時間混合した粉体を０．１〜２・２ｔｏｎ／ｃｍ
２（１０〜２２０ＭＰａ）の各圧力で金型成形した。そ
れらの成形体を非酸化性雰囲気下にて８００℃で仮焼成
した後、非酸化性雰囲気下において２１００℃で３時間
焼成して、各種の平均気孔半径を有する炭素−炭化ホウ
素焼結体（ホウ素含有濃度１６質量％）を製造した。Examples 1 to 4, Comparative Example 1 and Reference Example 1 70% by mass of mesocarbon microbeads (average particle size 20 μm) produced by heat treatment of coal tar pitch, boron carbide powder (average particle size 15 μm) 20 Mass% and artificial graphite powder (average particle size 15 μm) 10 mass% were mixed and mixed for 1 hour at normal pressure to obtain a powder of 0.1 to 2.2 ton / cm.
Molding was performed at each pressure of 2 (10 to 220 MPa). After preliminarily calcining these molded bodies at 800 ° C. in a non-oxidizing atmosphere, they are calcined at 2100 ° C. for 3 hours in a non-oxidizing atmosphere to obtain carbon-boron carbide sintered bodies having various average pore radii ( A boron content concentration of 16% by mass) was produced.
【００２８】実施例５〜９、比較例２、３及び参考例２ 炭化ホウ素粉（平均粒径１５μｍ）４０質量％と生コー
クス粉（揮発分１０質量％、平均粒径１５μｍ）６０質
量％とを、らいかい機で３０時間摩砕混合して平均粒径
３μｍの混合粉末にし０．１〜２．２ｔｏｎ／ｃｍ
２（１０〜２２０ＭＰａ）の各圧力で金型成形した。そ
れらの成形体を非酸化性雰囲気下にて２２００℃で１時
間焼成して、平均気孔半径の異なる炭素−炭化ホウ素焼
結体（ホウ素含有濃度３１質量％）を製造した。Examples 5 to 9, Comparative Examples 2 and 3, and Reference Example 2 40% by mass of boron carbide powder (average particle size 15 μm) and 60% by mass of raw coke powder (volatile content 10% by mass, average particle size 15 μm). Is ground and mixed for 30 hours by a raker machine to obtain a mixed powder having an average particle diameter of 3 μm, which is 0.1 to 2.2 ton / cm.
Molding was performed at each pressure of 2 (10 to 220 MPa). The compacts were fired at 2200 ° C. for 1 hour in a non-oxidizing atmosphere to produce carbon-boron carbide sintered bodies (boron content concentration 31 mass%) having different average pore radii.
【００２９】それぞれの方法で得られた焼結体につい
て、平均気孔半径と曲げ強さの測定及びアルミナ板との
固着試験を行った。結果を表１に示す。With respect to the sintered bodies obtained by the respective methods, the average pore radius and the bending strength were measured, and the adhesion test with the alumina plate was conducted. The results are shown in Table 1.
【００３０】[0030]
【表１】 [Table 1]
【００３１】固着試験は、寸法２０×２０×１０（ｍ
ｍ）、表面粗さＲａが３．２μｍに加工した焼結体に、
同形状のアルミナ板（表面粗さＲａ６．３μｍ）を乗せ
て、空気中８００℃で３時間加熱して行った。ここで、
参考例１（平均気孔半径３０μｍ）及び参考例２（平均
気孔半径１９μｍ）は強度が弱く、加工の際に形状が少
し崩れた。The adhesion test was conducted with the dimensions of 20 × 20 × 10 (m
m) and a surface roughness Ra of 3.2 μm processed into a sintered body,
An alumina plate (surface roughness Ra: 6.3 μm) of the same shape was placed, and heating was performed in air at 800 ° C. for 3 hours. here,
In Reference Example 1 (average pore radius 30 μm) and Reference Example 2 (average pore radius 19 μm), the strength was weak and the shape was a little broken during processing.
【００３２】曲げ強さの測定は、各焼結体を１０×１０
×６０（ｍｍ）に加工して、スパン４０ｍｍの３点曲げ
法にて行った。Bending strength was measured by measuring each sintered body at 10 × 10.
It was processed into × 60 (mm) and was performed by a three-point bending method with a span of 40 mm.
【００３３】表１から、焼結体の平均気孔半径が０．１
乃至１０μｍであれば固着しないことが分かる。From Table 1, the average pore radius of the sintered body is 0.1.
It can be seen that if the thickness is 10 μm to 10 μm, no fixation occurs.
【００３４】また、ホウ素含有濃度５質量％及び４０質
量％の炭素−炭化ホウ素焼結体を製造し、上記と同様に
加工して固着試験を行ってみたが、平均気孔半径が０．
１〜１０μｍであればアルミナ板とは固着しなかった。A carbon-boron carbide sintered body having a boron content of 5% by mass and a mass of 40% by mass was produced and processed in the same manner as above to carry out a sticking test.
If it was 1 to 10 μm, it did not adhere to the alumina plate.
【００３５】＜炭素−炭化ホウ素−炭化ケイ素焼結体＞<Carbon-Boron Carbide-Silicon Carbide Sintered Body>
【００３６】メソカーボンマイクロビーズ（平均粒径２
０μｍ）７０質量％、炭化ホウ素粉（平均粒径１５μ
ｍ）７質量％及び炭化ケイ素粉（平均粒径１５μｍ）２
３質量％とを配合して、らいかい機で１時間混合した粉
体を０．２〜２ｔｏｎ／ｃｍ２（２０〜２００ＭＰａ）
の各圧力で金型成形した。この成形体を非酸化性雰囲気
下にて２２００℃で５時間焼成して、各種の平均気孔半
径を有する炭素−炭化ホウ素焼結体（ホウ素含有濃度５
質量％）を製造した。Mesocarbon microbeads (average particle size 2
70 μm), boron carbide powder (average particle size 15 μm
m) 7 mass% and silicon carbide powder (average particle size 15 μm) 2
0.2 to 2 ton / cm 2 (20 to 200 MPa) of powder mixed with 3 mass% and mixed for 1 hour with a raker machine
Molding was performed at each pressure. This molded body was fired at 2200 ° C. for 5 hours in a non-oxidizing atmosphere to give a carbon-boron carbide sintered body having various average pore radii (boron content concentration: 5
Mass%).
【００３７】これを上記と同様に加工して固着試験を行
ってみたが、平均気孔半径が０．１〜１０μｍであれば
アルミナ板とは固着しなかった。When this was processed in the same manner as above and a sticking test was conducted, it did not stick to the alumina plate when the average pore radius was 0.1 to 10 μm.
【００３８】また、ホウ素含有濃度２０質量％及び４０
質量％の炭素−炭化ホウ素−炭化ケイ素焼結体を製造
し、上記と同様に加工して固着試験を行ってみたが、平
均気孔半径が０．１〜１０μｍであればアルミナ板とは
固着しなかった。Further, the boron content concentration is 20% by mass and 40%.
A mass% carbon-boron carbide-silicon carbide sintered body was produced, and processed in the same manner as above to carry out a sticking test. However, if the average pore radius is 0.1 to 10 μm, it sticks to the alumina plate. There wasn't.
【００３９】なお、焼結体の気孔半径は水銀圧入法で測
定し、使用した測定装置はカルロ・エルバ社製、水銀の
表面張力は０．４１Ｎ／ｍ、水銀と焼結体との接触角は
１４０°とし、平均気孔半径は測定された気孔半径０．
０１〜１００μｍでの累積気孔容積の１／２に相当する
気孔半径とした。The pore radius of the sintered body was measured by the mercury press-in method. The measuring apparatus used was made by Carlo Erba Co., the surface tension of mercury was 0.41 N / m, and the contact angle between mercury and the sintered body was measured. Is 140 °, and the average pore radius is 0.
The pore radius was equivalent to 1/2 of the cumulative pore volume at 01 to 100 μm.
【００４０】[0040]
【発明の効果】本発明に係る炭素−炭化ホウ素焼結体及
び炭素−炭化ホウ素−炭化ケイ素焼結体は、ホウ素含有
濃度と平均気孔半径とが特定の範囲であるため、接触す
る相手部材との固着を防止することができ、炉内部品や
治具等に好適に使用できる焼結体を提供することができ
る。EFFECTS OF THE INVENTION The carbon-boron carbide sintered body and the carbon-boron carbide-silicon carbide sintered body according to the present invention have a boron content concentration and an average pore radius within a specific range, and therefore, are to be contacted with a mating member. It is possible to provide a sintered body which can be prevented from sticking and can be suitably used for parts in a furnace, jigs and the like.
フロントページの続き (72)発明者 曽我部 敏明 香川県三豊郡大野原町大字中姫2181−２ 東洋炭素株式会社大野原技術開発センター 内Front Page Continuation (72) Inventor Toshiaki Sogabe 2181 Nakahime, Onohara Town, Mitoyo District, Kagawa Prefecture Toyo Tanso Co., Ltd. Onohara Technology Development Center
Claims (1)
り、且つ、水銀圧入法による平均気孔半径が０．１乃至
１０マイクロメータであることを特徴とする炭素−炭化
ホウ素焼結体又は炭素−炭化ホウ素−炭化ケイ素焼結
体。1. A carbon-boron carbide sintered body or carbon having a boron content concentration of 5 to 40 mass% and an average pore radius of 0.1 to 10 micrometers measured by a mercury intrusion method. -Boron carbide-Silicon carbide sintered body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28854994A JP3966911B2 (en) | 1994-10-17 | 1994-10-17 | In-furnace members and jigs |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28854994A JP3966911B2 (en) | 1994-10-17 | 1994-10-17 | In-furnace members and jigs |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08119741A true JPH08119741A (en) | 1996-05-14 |
| JP3966911B2 JP3966911B2 (en) | 2007-08-29 |
Family
ID=17731689
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28854994A Expired - Fee Related JP3966911B2 (en) | 1994-10-17 | 1994-10-17 | In-furnace members and jigs |
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| Country | Link |
|---|---|
| JP (1) | JP3966911B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011051867A (en) * | 2009-09-04 | 2011-03-17 | Toyo Tanso Kk | Ceramic carbon composite, method of manufacturing the same, ceramic applied ceramic carbon composite and method of manufacturing the same |
| JP2014159353A (en) * | 2013-02-20 | 2014-09-04 | Nihon Ceratec Co Ltd | Composite material and method of producing the same |
| WO2015025612A1 (en) * | 2013-08-23 | 2015-02-26 | 東洋炭素株式会社 | Carbon material and heat treatment jig using said carbon material |
-
1994
- 1994-10-17 JP JP28854994A patent/JP3966911B2/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011051867A (en) * | 2009-09-04 | 2011-03-17 | Toyo Tanso Kk | Ceramic carbon composite, method of manufacturing the same, ceramic applied ceramic carbon composite and method of manufacturing the same |
| TWI481581B (en) * | 2009-09-04 | 2015-04-21 | Toyo Tanso Co | Ceramic carbon composite and method for producing the same, and ceramic -coated ceramic carbon composite and method for producing the same |
| US9296660B2 (en) | 2009-09-04 | 2016-03-29 | Toyo Tanso Co., Ltd. | Ceramic carbon composite material, method for producing ceramic carbon composite material, ceramic-coated ceramic carbon composite material, and method for producing ceramic-coated ceramic carbon composite material |
| JP2014159353A (en) * | 2013-02-20 | 2014-09-04 | Nihon Ceratec Co Ltd | Composite material and method of producing the same |
| WO2015025612A1 (en) * | 2013-08-23 | 2015-02-26 | 東洋炭素株式会社 | Carbon material and heat treatment jig using said carbon material |
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