JP3855671B2 - Method for producing cubic boron nitride - Google Patents

Method for producing cubic boron nitride Download PDF

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JP3855671B2
JP3855671B2 JP2001089029A JP2001089029A JP3855671B2 JP 3855671 B2 JP3855671 B2 JP 3855671B2 JP 2001089029 A JP2001089029 A JP 2001089029A JP 2001089029 A JP2001089029 A JP 2001089029A JP 3855671 B2 JP3855671 B2 JP 3855671B2
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boron nitride
cubic boron
nitride
alkaline earth
producing
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JP2002284511A (en
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飯塚　　誠
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Showa Denko KK
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Showa Denko KK
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Priority to JP2001089029A priority Critical patent/JP3855671B2/en
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Priority to CN 02801387 priority patent/CN1200908C/en
Priority to KR10-2002-7016041A priority patent/KR100525962B1/en
Priority to AT02707181T priority patent/ATE328852T1/en
Priority to DE60212100T priority patent/DE60212100T2/en
Priority to US10/344,645 priority patent/US7014826B2/en
Priority to EP02707181A priority patent/EP1373163B1/en
Priority to PCT/JP2002/002987 priority patent/WO2002076906A2/en
Publication of JP2002284511A publication Critical patent/JP2002284511A/en
Priority to ZA200209614A priority patent/ZA200209614B/en
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Description

【０００１】
【発明の属する技術分野】
本発明は、六方晶窒化ホウ素から立方晶窒化ホウ素を製造する方法および製造物に関する。
【０００２】
【従来の技術】
立方晶窒化ホウ素は、ダイヤモンドに次ぐ硬さと、それをしのぐ化学的安定性を持ち、研削・研磨・切削材としての需要が増大している。立方晶窒化ホウ素の製造方法は種々考案されており、最も良く知られ工業的にも広く利用されているのは、六方晶窒化ホウ素を、触媒物質の存在下で、約4.0〜6.0GPa、約1400〜1600℃程度の立方晶窒化ホウ素の熱力学的安定領域内に保持して、六方晶窒化ホウ素を立方晶窒化ホウ素に変換する方法である。触媒物質としては、米国特許3,772,428号公報、特公昭61-283号公報、特公平5-94公報、特公平5-95号公報には、アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物が開示されている。すなわち、米国特許3,772,428号には、Li3NあるいはLi3BN2が特に有望な触媒物質とされている。しかし、これらの触媒物質を使用して得られる立方晶窒化ホウ素は、一般に50μm以下の微粒子であり、かつ結晶面の発達が乏しく、研削砥粒として十分な性能を示すに至っていない。
特公昭61-283号公報には、LiCaBN2が有望な触媒物質として開示されている。この触媒物質を使用して得られる立方晶窒化ホウ素は、全体として球形に近い形状を示し、機械的強度が優れている。また、特公平5-94号公報および特公平5-95号公報には、触媒物質として、LiMBN2（Mはアルカリ土類金属を示す。）と、Li8SiN4またはCa5Si2N6との混合物を使用する方法が示されている。この方法により得られる立方晶窒化ホウ素は、結晶の(111)面が発達し、機械的強度に優れている。
しかしながら、これらの方法においては、六方晶窒化ホウ素から立方晶窒化ホウ素への変換率が未だ十分でなく工業的にはより変換率の高い触媒物質が求められている。また機械的強度についても、より高いものが求められている。
【０００３】
【発明が解決しようとする課題】
本発明の目的は、上記のような従来技術の問題点を改良し、六方晶窒化ホウ素を高い機械的強度を有する立方晶窒化ホウ素に変換し、且つ、立方晶窒化ホウ素への変換率を高めることにある。
【０００４】
【課題を解決するための手段】
本発明者は上記課題を解決すべく、鋭意努力検討した結果、本発明に到達した。即ち本発明は、以下に関する。
(1)六方晶窒化ホウ素を、触媒物質の存在下、立方晶窒化ホウ素の熱力学的安定領域内に保持して、立方晶窒化ホウ素に変換する立方晶窒化ホウ素の製造方法において、前記触媒物質がLiMBN2（Mは、Ca、Sr、Ba、Ra、Be、Mgを示す。）と、アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物からなる群から選ばれた少なくとも1種とを含むことを特徴とする立方晶窒化ホウ素の製造方法。
(2)前記LiMBN2が、酸素含有量が1%以下であることを特徴とする(1)に記載の立方晶窒化ホウ素の製造方法。
(3)前記アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物が、酸素含有量が1%以下であることを特徴とする(1)または(2)に記載の立方晶窒化ホウ素の製造方法。
(4)前記LiMBN2が、LiCaBN2またはLiBaBN2であることを特徴とする(1)〜(3)の何れか1項に記載の立方晶窒化ホウ素の製造方法。
(5)前記アルカリ金属の窒化物が、Na、K、Rb、Cs、Frの窒化物であることを特徴とする(1)〜(4)の何れか1項に記載の立方晶窒化ホウ素の製造方法。
(6)前記アルカリ土類金属の窒化物が、Ra、Be、Mgの窒化物であることを特徴とする(1)〜(5)の何れか1項に記載の立方晶窒化ホウ素の製造方法。
(7)前記アルカリ土類金属の窒化物が、Mgの窒化物であることを特徴とする(1)〜(5)の何れか1項に記載の立方晶窒化ホウ素の製造方法。
(8)前記アルカリ金属のホウ窒化物が、Li3BN2であることを特徴とする(1)〜(7)の何れか1項に記載の立方晶窒化ホウ素の製造方法。
(9)前記アルカリ土類金属のホウ窒化物が、Ca3B2N4またはMg3B2N4であることを特徴とする(1)〜(8)の何れか1項に記載の立方晶窒化ホウ素の製造方法。
(10)前記アルカリ土類金属のホウ窒化物が、Ca3B2N4であることを特徴とする(1)〜(9)の何れか1項に記載の立方晶窒化ホウ素の製造方法。
(11)触媒物質が、LiCaBN2とLi3BN2とを含むことを特徴とする(1)〜(3)の何れか1項に記載の立方晶窒化ホウ素の製造方法。
(12)LiMBN2と、アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物からなる群より選ばれた物質との比率が、LiMBN2をモル数として1部に対し、アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物の総モル数を0.3〜20部とすることを特徴とする(1)〜(11)の何れか1項に記載の立方晶窒化ホウ素の製造方法。
(13)六方晶窒化ホウ素100質量部に対し、触媒物質を5〜50質量部の範囲内で含有させ、該含有物を立方晶窒化ホウ素の熱力学的安定領域内に保持して、六方晶窒化ホウ素を立方晶窒化ホウ素に変換する(1)〜(12)の何れか1項に記載の立方晶窒化ホウ素の製造方法。
(14)(1)〜(13)の何れか1項に記載の立方晶窒化ホウ素の製造方法を用いて製造した立方晶窒化ホウ素。
(15)(14)に記載の立方晶窒化ホウ素を用いて製造した研削砥石。
【０００５】
【発明の実施の形態】
本発明は、六方晶窒化ホウ素を、触媒物質の存在下、立方晶窒化ホウ素の熱力学的安定領域内に保持して、六方晶窒化ホウ素を立方晶窒化ホウ素に変換する立方晶窒化ホウ素の製造方法を提供する。この製造方法の一例を示すと、六方晶窒化ホウ素の粉末を、触媒物質と混合し、例えば1〜2t/cm2の圧力で成形体とした後、その成形体を超高圧発生装置の容器内に設置し、約4〜6GPa、約1400〜約1600℃程度の立方晶窒化ホウ素の熱力学的安定領域内に、例えば1秒〜6時間程度保持して、六方晶窒化ホウ素を立方晶窒化ホウ素に変換する。変換後、超高圧発生装置内から合成塊を取り出し、立方晶窒化ホウ素を単離精製する。
【０００６】
本発明の出発原料である六方晶窒化ホウ素は、市販の六方晶窒化ホウ素粉末を使用できる。しかし、酸化ホウ素等の形で混入する酸素不純物は、六方晶窒化ホウ素から立方晶窒化ホウ素への変換を遅らせることがあるため、酸素量の少ない六方晶窒化ホウ素を用いるのが好ましい。すなわち酸素含有量が1%以下の六方晶窒化ホウ素粉末を用いるのが好ましい。また、六方晶窒化ホウ素の粒径については、最大粒径が100μm以下であることが好ましい。粒径が大きすぎると六方晶窒化ホウ素と触媒物質との反応性が低下し、立方晶窒化ホウ素への変換率が低下するため好ましくない。
【０００７】
本発明では触媒物質として、LiMBN2と、アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物からなる群から選ばれた少なくとも1種（LiMBN2を除く。）を用いる。LiMBN2のMは、CaまたはSrまたはBaまたはRaまたはBeまたはMgを示すが、この中で特に、CaまたはBaが好ましい。また、LiMBN2は酸素不純物の少ないものが好ましく、特に酸素含有量が1%以下、より好ましくは0.5%以下のものを用いることが好ましい。酸素不純物は、六方晶窒化ホウ素から立方晶窒化ホウ素への変換を遅らせ好ましくない。
【０００８】
LiMBN2の粒径は特に限定されないが、一般的には最大粒径が100μm以下であることが好ましい。粒径が大きすぎると六方晶窒化ホウ素との反応性が低下し、立方晶窒化ホウ素への変換率が低下するため好ましくない。
【０００９】
本発明のLiMBN2の合成方法を、例えば、LiCaBN2を用いて説明する。先ず、原料として窒化リチウム、窒化カルシウム、六方晶窒化ホウ素の粉末を用いる。これら粉末をモル比で窒化リチウム：窒化カルシウム：六方晶窒化ホウ素＝1：1：3の割合に配合し、窒素もしくはアルゴン等の不活性雰囲気下、約1000℃に40分程度保持した後冷却して、凝固したLiCaBN2を得る。これを不活性ガス雰囲気中で粉砕して、LiCaBN2粉末とする。
【００１０】
本発明では触媒物質としてLiMBN2と共に、アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物からなる群から選ばれた少なくとも1種を用いる必要がある。なお、アルカリ金属、アルカリ土類金属の窒化物およびこれらのホウ窒化物は、同時に用いているLiMBN2以外から選択する必要がある。
【００１１】
アルカリ金属とは、具体的にはLi, Na, K, Rb, Cs, Frである。この中で特にLiを用いた場合、より高い変換率で機械的強度の優れた立方晶窒化ホウ素を製造することができる。
【００１２】
アルカリ土類金属とは、具体的にはCa, Sr, Ba, Ra, Be, Mgである。この中で特に、Ca, Mgを用いた場合、より高い変換率で機械的強度の優れた立方晶窒化ホウ素を製造することができる。
【００１３】
アルカリ金属の窒化物とは、例えば、Li3N, Na3N, K3N, Rb3N, Cs3N, Fr3Nが例示できる。この中で特に、Na3N, K3N, Rb3N, Cs3N, Fr3Nを用いた場合、より高い変換率で機械的強度の優れた立方晶窒化ホウ素を製造することができる。
【００１４】
アルカリ土類金属の窒化物とは、例えば、Ca3N2, Sr3N2, Ba3N2, Ra3N2, Be3N2, Mg3N2が例示できる。この中で特に、Ra3N2, Be3N2, Mg3N2を用いた場合、より高い変換率で機械的強度の優れた立方晶窒化ホウ素を製造することができる。
【００１５】
アルカリ金属のホウ窒化物とは、例えば、Li3BN2, Na3BN2, K3BN2, Rb3BN2, Cs3BN2, Fr3BN2が例示できる。この中で特に、Li3BN2を用いた場合、より高い変換率で機械的強度の優れた立方晶窒化ホウ素を製造することができる。
【００１６】
アルカリ土類金属のホウ窒化物とは、例えば、Ca3B2N4, Sr3B2N4, Ba3B2N4, Ra3B2N4, Be3B2N4, Mg3B2N4が例示できる。この中で特に、Ca3B2N4, Mg3B2N4を用いた場合、より高い変換率で機械的強度の優れた立方晶窒化ホウ素を製造することができる。
【００１７】
本発明で用いる、アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物は不純物濃度の低いものを用いることが好ましい。特に不純物として酸素を含有することの悪影響は大きく、酸素不純物の含有量を好ましくは1%以下、より好ましくは0.5%以下とする。酸素含有量が1%より高くなると、製造される立方晶窒化ホウ素の結晶性が低下する。
【００１８】
本発明で用いる、アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物の粒径は特に限定されないが、一般的には最大粒径が100μm以下であることが好ましい。粒径が大きすぎると六方晶窒化ホウ素との反応性が低下するからである。
【００１９】
本発明では触媒物質として、LiCaBN2と、Li, Ca, Mg, Na3N, K3N, Rb3N, Cs3N, Fr3N, Ra3N2, Be3N2, Mg3N2, Li3BN2, Ca3B2N4, Mg3B2N4を併用した場合が特に好ましいが、この中で併用するのが最も好ましいのは、LiCaBN2と、Li3BN2を併用する場合である。この場合が最も高い変換率で機械的強度の優れた立方晶窒化ホウ素を製造することができる。
【００２０】
本発明で用いられるLiMBN2と、アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物からなる群より選ばれる少なくとも1種を含む物質の比率は、LiMBN2をモル数として1部に対し、アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物の総モル数を、好ましくは0.3〜20部、より好ましくは0.3〜10部の割合とする。アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物の総モル数が0.3部より少ないと、これらの効果が十分に発揮されず、また立方晶窒化ホウ素への変換率が減少し、逆に20部を超えると立方晶窒化ホウ素の生成速度が過大となり、機械的強度および形状性が劣化し、砥粒性能の低下をもたらす。
【００２１】
上記触媒物質の調整方法としては、LiMBN2粉末と、アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物からなる群より選ばれる少なくとも1種の粉末を混合する方法がある。また、別の方法としては、アルカリ金属、アルカリ土類金属およびこれらの窒化物を目的とする比率となるように配合し、例えば、窒素もしくはアルゴン等の不活性雰囲気下で700〜1200℃程度に加熱して得る方法もある。
【００２２】
本発明では、触媒物質として、LiMBN2と、アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物からなる群から選ばれた少なくとも1種を用いるが、これらの物質を六方晶窒化ホウ素と混合し、この混合物を立方晶窒化ホウ素の熱力学的安定領域内に保持して、六方晶窒化ホウ素を立方晶窒化ホウ素に変換する製造方法以外に、アルカリ金属、アルカリ土類金属およびこれらの窒化物およびこれらのホウ化物等を六方晶窒化ホウ素と混合し、この混合物を立方晶窒化ホウ素の熱力学的安定領域内に保持した段階で、混合物内にLiMBN2と、アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物からなる群から選ばれた少なくとも1種を存在させても良い。
【００２３】
本発明で用いられる上記触媒物質の配合比率は、六方晶窒化ホウ素100質量部に対し、触媒物質を好ましくは5〜50質量部、より好ましくは10〜30質量部である。触媒物質の配合比率が5質量部より低い場合、または50質量部より高い場合は、立方晶窒化ホウ素の機械的強度および形状性が劣化し、砥粒性能の低下をもたらす。
【００２４】
上記触媒物質と六方晶窒化ホウ素の調整方法としては、これらの粉末を一緒に混合して用いる方法が好ましいが、、反応容器中に六方晶窒化ホウ素層と触媒物質層を交互に積層するように配置する方法でも良い。具体的には、六方晶窒化ホウ素と触媒物質とを混合した後、あるいは別々に、1〜2t/cm2程度の圧力で成形してから反応容器に充填することが好ましい。この方法を用いることにより原料粉末の取り扱い性が向上すると共に、反応容器内ので収縮量が減少し、生産性が向上する効果が得られる。
【００２５】
尚、上記成形体または積層体に前もって立方晶窒化ホウ素をシードとして添加し、これを核として立方晶窒化ホウ素の結晶成長を促進させる方法もあるが、当然のことながら、これらの方法も本発明に含まれる。この場合、シード表面に上記触媒物質を被覆して用いても良い。
【００２６】
上記の成形物を反応容器中に充填し、周知の高温高圧発生装置に装填し、立方晶窒化ホウ素の熱力学的安定領域内の温度圧力条件下に保持する。この熱力学的安定領域は、O.Fukunaga, Diamond Relat. Mater., 9, (2000), 7-12 に示されている。保持時間は特に限定されず、一般的には1秒〜6時間程度でよい。
【００２７】
上記熱力学的安定領域に保持することにより、六方晶窒化ホウ素は立方晶窒化ホウ素に変換され、一般的には六方晶窒化ホウ素、立方晶窒化ホウ素および触媒物質からなる合成塊が得られる。この合成塊を解砕し、立方晶窒化ホウ素を単離精製する。単離精製方法は、特公昭49-27757号公報に記載されている方法を用いることができる。一例として、合成塊を5mm以下に解砕した後、水酸化ナトリウムと少量の水を加え、320℃程度に加熱する。この方法により六方晶窒化ホウ素が選択的に溶解するので、これを冷却後、酸で洗浄ろ過することにより立方晶窒化ホウ素が得られる。
【００２８】
【実施例】
（実施例1〜10、比較例1〜6）
不純物として酸素0.8%、その他の不純物0.2%を含有する、平均粒径10μmの六方晶窒化ホウ素粉末に、表1に示す割合で構成された触媒物質を、六方晶窒化ホウ素100質量部に対し触媒物質10質量部の割合で配合した。なお、表中の触媒物質の構成比は、LiMBN2をモル数として1部に対する、LiMBN2以外のアルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物の総モル数の比を示す。これらを1.5t/cm2の圧力で直径26mm、高さ32mmの成形体とし、図1に示す反応容器に収容した。
【表１】

Figure 0003855671
【００２９】
図1に示す反応容器において、容器外壁1は伝圧体としてのパイロフィライトによって円筒状に作られ、その内側には黒鉛円筒体からなるヒーター2および隔壁材としてのパイロフィライト8が配設されている。また容器の上下端はそれぞれ通電用鋼製リング3および通電用鋼板4が配設され、その内側には焼結アルミナ板5および伝圧体としてのパイロフィライト6が配設され、そしてそのパイロフィライト6および隔壁材としてのパイロフィライト8によって取り囲まれる空間が反応原料を収容する収容室7となっている。
【００３０】
この反応容器を超高圧発生装置内に設置し、上記成形体を5GPa、1450℃の条件で10分間処理した。
【００３１】
処理後、超高圧発生装置内から得られた合成塊を取り出し、合金塊の一部について、合成塊を5mm以下に解砕した後、水酸化ナトリウムと少量の水を加え、320℃程度に加熱し、これを冷却後、酸で洗浄ろ過することにより立方晶窒化ホウ素を単離精製した。
【００３２】
また、得られた合成塊の一部を乳鉢で粉砕し、X線粉末回折装置により、CuKα線に対する立方晶窒化ホウ素(111)および六方晶窒化ホウ素(002)回折線の強度比を測定し、立方晶窒化ホウ素への変換率を（立方晶窒化ホウ素の強度／（立方晶窒化ホウ素の強度＋六方晶窒化ホウ素の強度））×100（単位：%）の計算式で求めた。
また、得られた立方晶窒化ホウ素の機械的強度をタフネス値により評価した。タフネス値は、得られた立方晶窒化ホウ素をJIS-B4130粒度区分120/140に粒度を調整し、この試料の一定量と鋼球1個を容積2mlのカプセルに入れ、このカプセルを振動数3000±100回/分の振動器で30.0±0.3秒間振動させ、カプセル内の立方晶窒化ホウ素粒を鋼球で粉砕した後、粉砕粉を90μmの篩網で篩別し、その篩網上の試料残存重量を粉砕粉全体の百分率で表した。
さらに、得られた立方晶窒化ホウ素の形状異方性をかさ比重により評価した。従来の立方晶窒化ホウ素の製造方法では比較的球形に近い形状の結晶が得られていた。しかし本発明では、細長や扁平形状にずれた異方形状の結晶が得られ易くなり、この形状異方性の高い結晶を用いた研削工具、切削工具等は高い研削性能、切削性能が得られた。形状異方性については、得られた立方晶窒化ホウ素のカサ比重を、立方晶窒化ホウ素の真密度(3.48g/cm3)で除すことにより求め、得られた値が、低い場合は形状異方性が高く、逆に高い場合は形状異方性が低いことを示す。
【００３３】
（実施例11、比較例7）
実施例1および比較例1の方法で製造した立方晶窒化ホウ素をJIS-B4130に規定された粒度区分に分級し、粒度区分100/120の砥粒を用いて砥石セグメントを作製した。砥粒、結合剤としてのホウ珪酸系ガラス質結合材、バインダー（フェノール樹脂使用）を、砥粒50体積%、結合材18体積%、バインダー20体積%の配合比率で混合し、150℃で加圧成形後、1000℃（大気雰囲気）で焼成した。なお、使用したバインダーは砥石焼成時に燃焼し気孔となる。作製した砥石セグメントをアルミ台金に接着して砥石化した後に、以下の条件で研削試験を行った。実施例1で得られた砥粒での評価結果を実施例11、比較例1で得られた砥粒での評価結果を比較例7として試験結果を表2に示す。なお、研削比は、砥石による被削材の研削体積を砥石の摩耗した体積で除した値を、研削動力は研削時の研削盤の消費電力を示す。すなわち、研削比が高いほど砥石の研削性能が高いこと、研削動力が低いほど砥石の研削性能が高いことを示す。
【表２】
Figure 0003855671
【００３４】
Figure 0003855671
【００３５】
【発明の効果】
本発明によれば、六方晶窒化ホウ素を十分な機械的強度を有する立方晶窒化ホウ素に変換することができ、且つ、立方晶窒化ホウ素への変換率も十分なものとすることができる。また、得られた立方晶窒化ホウ素は、高い形状異方性を持ち合わせることから、切れ味が要求される研削砥粒用途に広く適用可能である。
【図面の簡単な説明】
【図１】六方晶窒化ホウ素を立方晶窒化ホウ素に変換するために用いる反応容器の断面を模式的にを示す。
【符号の説明】
1 容器外壁
2 ヒーター
3 通電用鋼製リング
4 通電用鋼板
5 焼結アルミナ板
6 パイロフィライト
7 収容室
8 パイロフィライト[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and a product for producing cubic boron nitride from hexagonal boron nitride.
[0002]
[Prior art]
Cubic boron nitride has hardness next to diamond and chemical stability that surpasses it, and the demand for grinding, polishing and cutting materials is increasing. Various methods for producing cubic boron nitride have been devised, and the most well known and widely used industrially is that hexagonal boron nitride is about 4.0 to 6.0 GPa, about 4.0 GPa in the presence of a catalyst substance. This is a method in which hexagonal boron nitride is converted to cubic boron nitride while being held in a thermodynamically stable region of cubic boron nitride at about 1400 to 1600 ° C. As catalyst materials, US Pat. No. 3,772,428, JP-B 61-283, JP-B 5-94, JP-B 5-95 include alkali metals, alkaline earth metals, nitrides thereof and these Boronitrides are disclosed. That is, in US Pat. No. 3,772,428, Li 3 N or Li 3 BN 2 is a particularly promising catalyst material. However, cubic boron nitride obtained using these catalyst materials is generally fine particles of 50 μm or less, and the crystal plane is poorly developed, so that it does not exhibit sufficient performance as a grinding abrasive grain.
Japanese Patent Publication No. 61-283 discloses LiCaBN 2 as a promising catalyst material. Cubic boron nitride obtained by using this catalyst material exhibits a nearly spherical shape as a whole, and has excellent mechanical strength. In Japanese Patent Publication No. 5-94 and Japanese Patent Publication No. 5-95, LiMBN 2 (M represents an alkaline earth metal) and Li 8 SiN 4 or Ca 5 Si 2 N 6 are used as catalyst materials. The method of using a mixture with is shown. The cubic boron nitride obtained by this method has a (111) plane of crystal and is excellent in mechanical strength.
However, in these methods, the conversion rate from hexagonal boron nitride to cubic boron nitride is not yet sufficient, and industrially, a catalytic substance having a higher conversion rate is required. Also, higher mechanical strength is required.
[0003]
[Problems to be solved by the invention]
The object of the present invention is to improve the above-mentioned problems of the prior art, convert hexagonal boron nitride to cubic boron nitride having high mechanical strength, and increase the conversion rate to cubic boron nitride. There is.
[0004]
[Means for Solving the Problems]
As a result of diligent efforts to solve the above problems, the present inventor has reached the present invention. That is, the present invention relates to the following.
(1) In the method for producing cubic boron nitride, in which hexagonal boron nitride is retained in the thermodynamic stability region of cubic boron nitride in the presence of the catalytic substance and converted to cubic boron nitride, the catalytic substance Is at least selected from the group consisting of LiMBN 2 (M represents Ca, Sr, Ba, Ra, Be, Mg) and alkali metals, alkaline earth metals, nitrides thereof, and boronitrides thereof A method for producing cubic boron nitride, comprising:
(2) The method for producing cubic boron nitride according to (1), wherein the LiMBN 2 has an oxygen content of 1% or less.
(3) The cubic crystal according to (1) or (2), wherein the alkali metal, alkaline earth metal, nitride thereof and boronitride have an oxygen content of 1% or less. A method for producing boron nitride.
(4) The method for producing cubic boron nitride according to any one of (1) to (3), wherein the LiMBN 2 is LiCaBN 2 or LiBaBN 2 .
(5) The cubic boron nitride according to any one of (1) to (4), wherein the alkali metal nitride is a nitride of Na, K, Rb, Cs, Fr Production method.
(6) The method for producing cubic boron nitride according to any one of (1) to (5), wherein the alkaline earth metal nitride is a nitride of Ra, Be, or Mg .
(7) The method for producing cubic boron nitride according to any one of (1) to (5), wherein the alkaline earth metal nitride is Mg nitride.
(8) The method for producing cubic boron nitride according to any one of (1) to (7), wherein the alkali metal boronitride is Li 3 BN 2 .
(9) The cubic according to any one of (1) to (8), wherein the alkaline earth metal boronitride is Ca 3 B 2 N 4 or Mg 3 B 2 N 4 A method for producing crystalline boron nitride.
(10) The method for producing cubic boron nitride according to any one of (1) to (9), wherein the alkaline earth metal boronitride is Ca 3 B 2 N 4 .
(11) The method for producing cubic boron nitride as described in any one of (1) to (3), wherein the catalyst material contains LiCaBN 2 and Li 3 BN 2 .
(12) and LiMBN 2, alkali metals, alkaline earth metals, the ratio of these nitrides and selected from the group consisting of boric nitride material, relative to 1 part of LiMBN 2 as moles, alkali Cubic crystals according to any one of (1) to (11), characterized in that the total number of moles of metal, alkaline earth metal, these nitrides and these boronitrides is 0.3 to 20 parts A method for producing boron nitride.
(13) The catalyst substance is contained in the range of 5 to 50 parts by mass with respect to 100 parts by mass of hexagonal boron nitride, and the inclusion is retained in the thermodynamic stability region of cubic boron nitride, 3. The method for producing cubic boron nitride according to any one of (1) to (12), wherein boron nitride is converted into cubic boron nitride.
(14) Cubic boron nitride produced using the method for producing cubic boron nitride according to any one of (1) to (13).
(15) A grinding wheel manufactured using the cubic boron nitride according to (14).
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The present invention produces cubic boron nitride that retains hexagonal boron nitride in the thermodynamically stable region of cubic boron nitride in the presence of a catalytic material to convert hexagonal boron nitride into cubic boron nitride. Provide a method. As an example of this production method, hexagonal boron nitride powder is mixed with a catalyst substance to form a molded body at a pressure of, for example, 1 to 2 t / cm 2 , and then the molded body is placed in a container of an ultrahigh pressure generator. The hexagonal boron nitride is retained in the thermodynamically stable region of cubic boron nitride at about 4 to 6 GPa and about 1400 to about 1600 ° C. for about 1 second to 6 hours, for example. Convert to After the conversion, the synthetic lump is taken out from the ultrahigh pressure generator and the cubic boron nitride is isolated and purified.
[0006]
As the hexagonal boron nitride which is the starting material of the present invention, commercially available hexagonal boron nitride powder can be used. However, since oxygen impurities mixed in the form of boron oxide or the like may delay the conversion from hexagonal boron nitride to cubic boron nitride, it is preferable to use hexagonal boron nitride having a small amount of oxygen. That is, it is preferable to use hexagonal boron nitride powder having an oxygen content of 1% or less. As for the particle size of hexagonal boron nitride, the maximum particle size is preferably 100 μm or less. If the particle size is too large, the reactivity between the hexagonal boron nitride and the catalyst substance is lowered, and the conversion rate to cubic boron nitride is lowered, which is not preferable.
[0007]
In the present invention, LiMBN 2 and at least one selected from the group consisting of alkali metals, alkaline earth metals, nitrides thereof and boronitrides (excluding LiMBN 2 ) are used as the catalyst substance. M in LiMBN 2 represents Ca, Sr, Ba, Ra, Be, or Mg, and among these, Ca or Ba is particularly preferable. Further, LiMBN 2 is preferably one having less oxygen impurities, and in particular, one having an oxygen content of 1% or less, more preferably 0.5% or less is preferably used. Oxygen impurities are undesirable because they delay the conversion of hexagonal boron nitride to cubic boron nitride.
[0008]
The particle size of LiMBN 2 is not particularly limited, but generally the maximum particle size is preferably 100 μm or less. If the particle size is too large, the reactivity with hexagonal boron nitride decreases, and the conversion rate to cubic boron nitride decreases, which is not preferable.
[0009]
A method for synthesizing LiMBN 2 of the present invention will be described using, for example, LiCaBN 2 . First, powders of lithium nitride, calcium nitride, and hexagonal boron nitride are used as raw materials. These powders were mixed in a molar ratio of lithium nitride: calcium nitride: hexagonal boron nitride = 1: 1: 3, kept at about 1000 ° C. for about 40 minutes under an inert atmosphere such as nitrogen or argon, and then cooled. Thus, solidified LiCaBN 2 is obtained. This is pulverized in an inert gas atmosphere to obtain LiCaBN 2 powder.
[0010]
In the present invention, it is necessary to use at least one selected from the group consisting of alkali metals, alkaline earth metals, nitrides thereof and boronitrides together with LiMBN 2 as a catalyst substance. Note that the alkali metal and alkaline earth metal nitrides and these boronitrides must be selected from materials other than LiMBN 2 used at the same time.
[0011]
Specifically, the alkali metal is Li, Na, K, Rb, Cs, or Fr. In particular, when Li is used, cubic boron nitride having a higher conversion rate and excellent mechanical strength can be produced.
[0012]
Specifically, the alkaline earth metal is Ca, Sr, Ba, Ra, Be, Mg. Among these, in particular, when Ca and Mg are used, cubic boron nitride having a higher conversion rate and excellent mechanical strength can be produced.
[0013]
Examples of the alkali metal nitride include Li 3 N, Na 3 N, K 3 N, Rb 3 N, Cs 3 N, and Fr 3 N. Among these, in particular, when Na 3 N, K 3 N, Rb 3 N, Cs 3 N, and Fr 3 N are used, cubic boron nitride having a higher conversion rate and excellent mechanical strength can be produced. .
[0014]
Examples of the alkaline earth metal nitride include Ca 3 N 2, Sr 3 N 2, Ba 3 N 2, Ra 3 N 2, Be 3 N 2 and Mg 3 N 2 . Among these, in particular, when Ra 3 N 2, Be 3 N 2, and Mg 3 N 2 are used, cubic boron nitride having a higher conversion rate and excellent mechanical strength can be produced.
[0015]
Examples of the alkali metal boronitride include Li 3 BN 2, Na 3 BN 2, K 3 BN 2, Rb 3 BN 2, Cs 3 BN 2, and Fr 3 BN 2 . Among these, in particular, when Li 3 BN 2 is used, cubic boron nitride having a higher conversion rate and excellent mechanical strength can be produced.
[0016]
Alkaline earth metal boronitride is, for example, Ca 3 B 2 N 4, Sr 3 B 2 N 4, Ba 3 B 2 N 4, Ra 3 B 2 N 4, Be 3 B 2 N 4, Mg 3 B 2 N 4 can be exemplified. Among these, in particular, when Ca 3 B 2 N 4 and Mg 3 B 2 N 4 are used, cubic boron nitride having a higher conversion rate and excellent mechanical strength can be produced.
[0017]
As the alkali metal, alkaline earth metal, nitrides thereof, and boronitrides used in the present invention, those having a low impurity concentration are preferably used. In particular, the adverse effect of containing oxygen as an impurity is great, and the content of oxygen impurity is preferably 1% or less, more preferably 0.5% or less. If the oxygen content is higher than 1%, the crystallinity of the produced cubic boron nitride is lowered.
[0018]
The particle diameters of the alkali metal, alkaline earth metal, nitrides thereof, and boronitrides used in the present invention are not particularly limited, but generally the maximum particle size is preferably 100 μm or less. This is because if the particle size is too large, the reactivity with hexagonal boron nitride decreases.
[0019]
In the present invention, LiCaBN 2 and Li, Ca, Mg, Na 3 N, K 3 N, Rb 3 N, Cs 3 N, Fr 3 N, Ra 3 N 2, Be 3 N 2, Mg 3 N are used as catalytic materials. 2, Li 3 BN 2, Ca 3 B 2 N 4, Mg 3 B 2 N 4 are particularly preferred, but it is most preferred to use LiCaBN 2 and Li 3 BN 2 together. It is a case where it uses together. In this case, cubic boron nitride having the highest conversion rate and excellent mechanical strength can be produced.
[0020]
The ratio of the substance containing at least one selected from the group consisting of LiMBN 2 used in the present invention and alkali metals, alkaline earth metals, nitrides thereof, and boronitrides is 1 with respect to the number of moles of LiMBN 2. The total number of moles of alkali metal, alkaline earth metal, these nitrides and these boronitrides is preferably 0.3 to 20 parts, more preferably 0.3 to 10 parts per part. If the total number of moles of alkali metal, alkaline earth metal, their nitrides, and their boronitrides is less than 0.3 parts, these effects are not fully exhibited, and the conversion rate to cubic boron nitride is reduced. On the other hand, if it exceeds 20 parts, the production rate of cubic boron nitride becomes excessive, the mechanical strength and shape deteriorate, and the abrasive performance is lowered.
[0021]
As a method for adjusting the catalyst substance, there is a method of mixing LiMBN 2 powder and at least one powder selected from the group consisting of alkali metals, alkaline earth metals, nitrides thereof and boronitrides. Further, as another method, alkali metal, alkaline earth metal and their nitrides are blended so as to have a desired ratio, for example, about 700 to 1200 ° C. in an inert atmosphere such as nitrogen or argon. There is also a method obtained by heating.
[0022]
In the present invention, as the catalyst material, at least one selected from the group consisting of LiMBN 2 and alkali metals, alkaline earth metals, nitrides thereof and boronitrides is used. In addition to the manufacturing method of mixing hexagonal boron nitride into cubic boron nitride by mixing with boron nitride and keeping the mixture in the thermodynamically stable region of cubic boron nitride, alkali metal, alkaline earth metal and When these nitrides and their borides are mixed with hexagonal boron nitride and the mixture is kept in the thermodynamic stability region of cubic boron nitride, LiMBN 2 and alkali metals, alkalis are contained in the mixture. There may be at least one selected from the group consisting of earth metals, their nitrides, and their boronitrides.
[0023]
The mixing ratio of the catalyst material used in the present invention is preferably 5 to 50 parts by mass, more preferably 10 to 30 parts by mass with respect to 100 parts by mass of hexagonal boron nitride. When the compounding ratio of the catalyst substance is lower than 5 parts by mass or higher than 50 parts by mass, the mechanical strength and shape of cubic boron nitride deteriorate, resulting in a decrease in abrasive performance.
[0024]
As a method for adjusting the catalyst material and the hexagonal boron nitride, a method of mixing and using these powders is preferable. However, the hexagonal boron nitride layer and the catalyst material layer are alternately laminated in the reaction vessel. The method of arranging may be used. Specifically, it is preferable that the hexagonal boron nitride and the catalyst material are mixed or separately molded at a pressure of about 1 to 2 t / cm 2 and then charged into the reaction vessel. By using this method, it is possible to improve the handleability of the raw material powder, reduce the amount of shrinkage in the reaction vessel, and improve the productivity.
[0025]
In addition, there is a method in which cubic boron nitride is added as a seed in advance to the molded body or laminate, and the crystal growth of cubic boron nitride is promoted by using this as a nucleus. Of course, these methods are also included in the present invention. include. In this case, the seed surface may be coated with the catalyst material.
[0026]
The above molded product is filled in a reaction vessel, charged into a well-known high-temperature and high-pressure generator, and maintained under temperature and pressure conditions within the thermodynamically stable region of cubic boron nitride. This thermodynamic stability region is shown in O. Fukunaga, Diamond Relat. Mater., 9, (2000), 7-12. The holding time is not particularly limited, and may generally be about 1 second to 6 hours.
[0027]
By holding in the thermodynamically stable region, hexagonal boron nitride is converted to cubic boron nitride, and generally a synthetic mass composed of hexagonal boron nitride, cubic boron nitride and a catalytic substance is obtained. This synthetic mass is crushed and cubic boron nitride is isolated and purified. As the isolation and purification method, the method described in JP-B-49-27757 can be used. As an example, after crushing the synthetic mass to 5 mm or less, sodium hydroxide and a small amount of water are added and heated to about 320 ° C. Since hexagonal boron nitride is selectively dissolved by this method, cubic boron nitride can be obtained by cooling and washing with acid after filtration.
[0028]
【Example】
(Examples 1 to 10, Comparative Examples 1 to 6)
Catalytic material composed of hexagonal boron nitride powder with an average particle size of 10 μm containing oxygen 0.8% and other impurities 0.2% as an impurity at a ratio shown in Table 1 to 100 parts by mass of hexagonal boron nitride. The substance was blended at a ratio of 10 parts by mass. Note that the configuration ratio of the catalytic material in the table, for one part of LiMBN 2 as moles, alkali metal other than LiMBN 2, alkaline earth metal, the ratio of the total moles of these nitrides and these boric nitride Indicates. These were molded into a molded body having a diameter of 26 mm and a height of 32 mm at a pressure of 1.5 t / cm 2 and accommodated in the reaction vessel shown in FIG.
[Table 1]
Figure 0003855671
[0029]
In the reaction container shown in FIG. 1, the outer wall 1 of the container is formed into a cylindrical shape by pyrophyllite as a pressure transmission body, and a heater 2 made of a graphite cylindrical body and a pyrophyllite 8 as a partition material are disposed inside the outer wall 1. Has been. In addition, the upper and lower ends of the container are respectively provided with an energizing steel ring 3 and an energizing steel plate 4, and on the inside thereof are disposed a sintered alumina plate 5 and a pyrophyllite 6 as a pressure transmission body. A space surrounded by the phyllite 6 and the pyrophyllite 8 as a partition wall material is a storage chamber 7 for storing the reaction raw material.
[0030]
The reaction vessel was placed in an ultrahigh pressure generator, and the molded body was treated for 10 minutes under conditions of 5 GPa and 1450 ° C.
[0031]
After processing, take out the synthetic lump obtained from the ultra high pressure generator, crush the synthetic lump to 5 mm or less for a part of the alloy lump, add sodium hydroxide and a small amount of water, and heat to about 320 ° C After cooling, cubic boron nitride was isolated and purified by washing and filtering with an acid.
[0032]
Moreover, a part of the obtained synthetic mass was pulverized in a mortar, and the intensity ratio of cubic boron nitride (111) and hexagonal boron nitride (002) diffraction lines with respect to CuKα rays was measured with an X-ray powder diffractometer, The conversion rate to cubic boron nitride was determined by a calculation formula of (strength of cubic boron nitride / (strength of cubic boron nitride + strength of hexagonal boron nitride)) × 100 (unit:%).
Further, the mechanical strength of the obtained cubic boron nitride was evaluated by a toughness value. The toughness value is obtained by adjusting the particle size of the obtained cubic boron nitride to JIS-B4130 particle size classification 120/140, placing a certain amount of this sample and one steel ball in a 2 ml volume capsule, and setting this capsule to a frequency of 3000 After vibrating for 30.0 ± 0.3 seconds with a vibrator of ± 100 times / minute, and crushing the cubic boron nitride particles in the capsule with a steel ball, the crushed powder is sieved with a 90 μm sieve mesh, and the sample on the sieve mesh The remaining weight was expressed as a percentage of the total ground powder.
Furthermore, the shape anisotropy of the obtained cubic boron nitride was evaluated by bulk specific gravity. In the conventional method for producing cubic boron nitride, crystals having a shape close to a spherical shape have been obtained. However, according to the present invention, it becomes easy to obtain anisotropically shaped crystals that are shifted into elongated or flat shapes, and grinding tools and cutting tools using crystals with high shape anisotropy can obtain high grinding performance and cutting performance. It was. The shape anisotropy was obtained by dividing the bulk density of cubic boron nitride obtained by the true density of cubic boron nitride (3.48 g / cm 3 ). If the anisotropy is high and conversely high, the shape anisotropy is low.
[0033]
(Example 11, Comparative Example 7)
Cubic boron nitride produced by the methods of Example 1 and Comparative Example 1 was classified into particle size classifications defined in JIS-B4130, and grindstone segments were produced using abrasive grains having a particle size classification of 100/120. Abrasive grains, borosilicate glassy binder as binder, binder (using phenolic resin) are mixed at a blending ratio of 50 volume% abrasive grains, 18 volume% binder and 20 volume% binder, and added at 150 ° C. After the pressure forming, it was fired at 1000 ° C. (atmospheric atmosphere). In addition, the used binder burns at the time of grindstone baking and becomes a pore. After the produced grindstone segment was bonded to an aluminum base metal to form a grindstone, a grinding test was performed under the following conditions. The evaluation results with the abrasive grains obtained in Example 1 are shown in Example 11, the evaluation results with the abrasive grains obtained in Comparative Example 1 are set as Comparative Example 7, and the test results are shown in Table 2. The grinding ratio is a value obtained by dividing the grinding volume of the work material by the grindstone by the worn volume of the grindstone, and the grinding power indicates the power consumption of the grinder during grinding. That is, the higher the grinding ratio, the higher the grinding performance of the grindstone, and the lower the grinding power, the higher the grinding performance of the grindstone.
[Table 2]
Figure 0003855671
[0034]
Figure 0003855671
[0035]
【The invention's effect】
According to the present invention, hexagonal boron nitride can be converted to cubic boron nitride having sufficient mechanical strength, and the conversion rate to cubic boron nitride can be sufficient. Moreover, since the obtained cubic boron nitride has a high shape anisotropy, it can be widely applied to grinding abrasive grains that require sharpness.
[Brief description of the drawings]
FIG. 1 schematically shows a cross-section of a reaction vessel used to convert hexagonal boron nitride to cubic boron nitride.
[Explanation of symbols]
1 Container outer wall
2 Heater
3 Steel ring for energization
4 Steel sheet for electricity
5 Sintered alumina plate
6 Pyrophyllite
7 containment room
8 Pyrophyllite

Claims (13)

六方晶窒化ホウ素を、触媒物質の存在下、立方晶窒化ホウ素の熱力学的安定領域内に保持して、立方晶窒化ホウ素に変換する立方晶窒化ホウ素の製造方法において、前記触媒物質がＬｉＭＢＮ２（Ｍは、Ｃａ、Ｓｒ、Ｂａ、Ｒａ、Ｂｅ、Ｍｇを示す。）と、アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物からなる群から選ばれた少なくとも１種とを含むことを特徴とする立方晶窒化ホウ素の製造方法。In the method for producing cubic boron nitride, in which hexagonal boron nitride is held in the thermodynamically stable region of cubic boron nitride in the presence of the catalytic material and converted into cubic boron nitride, the catalytic material is LiMBN 2. (M represents Ca, Sr, Ba, Ra, Be, Mg) and at least one selected from the group consisting of alkali metals, alkaline earth metals, nitrides thereof, and boron nitrides thereof. A method for producing cubic boron nitride, comprising: 前記ＬｉＭＢＮ２が、酸素含有量が１％以下であることを特徴とする請求項１に記載の立方晶窒化ホウ素の製造方法。The method for producing cubic boron nitride according to claim 1, wherein the LiMBN 2 has an oxygen content of 1% or less. 前記アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物が、酸素含有量が１％以下であることを特徴とする請求項１または２に記載の立方晶窒化ホウ素の製造方法。3. The method for producing cubic boron nitride according to claim 1, wherein the alkali metal, alkaline earth metal, nitride thereof, and boron nitride thereof have an oxygen content of 1% or less. . 前記ＬｉＭＢＮ２が、ＬｉＣａＢＮ２またはＬｉＢａＢＮ２であることを特徴とする請求項１〜３の何れか１項に記載の立方晶窒化ホウ素の製造方法。The method for producing cubic boron nitride according to any one of claims 1 to 3, wherein the LiMBN 2 is LiCaBN 2 or LiBaBN 2 . 前記アルカリ金属の窒化物が、Ｎａ、Ｋ、Ｒｂ、Ｃｓ、Ｆｒの窒化物であることを特徴とする請求項１〜４の何れか１項に記載の立方晶窒化ホウ素の製造方法。The method for producing cubic boron nitride according to any one of claims 1 to 4, wherein the alkali metal nitride is a nitride of Na, K, Rb, Cs, or Fr. 前記アルカリ土類金属の窒化物が、Ｒａ、Ｂｅ、Ｍｇの窒化物であることを特徴とする請求項１〜５の何れか１項に記載の立方晶窒化ホウ素の製造方法。The method for producing cubic boron nitride according to any one of claims 1 to 5, wherein the alkaline earth metal nitride is a nitride of Ra, Be, or Mg. 前記アルカリ土類金属の窒化物が、Ｍｇの窒化物であることを特徴とする請求項１〜５の何れか１項に記載の立方晶窒化ホウ素の製造方法。The method for producing cubic boron nitride according to any one of claims 1 to 5, wherein the alkaline earth metal nitride is Mg nitride. 前記アルカリ金属のホウ窒化物が、Ｌｉ３ＢＮ２であることを特徴とする請求項１〜７の何れか１項に記載の立方晶窒化ホウ素の製造方法。The method for producing cubic boron nitride according to claim 1, wherein the alkali metal boronitride is Li 3 BN 2 . 前記アルカリ土類金属のホウ窒化物が、Ｃａ３Ｂ２Ｎ４またはＭｇ３Ｂ２Ｎ４であることを特徴とする請求項１〜８の何れか１項に記載の立方晶窒化ホウ素の製造方法。Boric nitride of the alkaline earth metal, the manufacture of cubic boron nitride according to any one of claims 1 to 8, which is a Ca 3 B 2 N 4 or Mg 3 B 2 N 4 Method. 前記アルカリ土類金属のホウ窒化物が、Ｃａ３Ｂ２Ｎ４であることを特徴とする請求項１〜９の何れか１項に記載の立方晶窒化ホウ素の製造方法。Boric nitride of the alkaline earth metal, Ca 3 B 2 method for producing cubic boron nitride according to any one of claims 1-9, characterized in that N is 4. 触媒物質が、ＬｉＣａＢＮ２とＬｉ３ＢＮ２とを含むことを特徴とする請求項１〜３の何れか１項に記載の立方晶窒化ホウ素の製造方法。The method for producing cubic boron nitride according to any one of claims 1 to 3 , wherein the catalyst material contains LiCaBN 2 and Li 3 BN 2 . ＬｉＭＢＮ２と、アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物からなる群より選ばれた物質との比率が、ＬｉＭＢＮ２をモル数として１部に対し、アルカリ金属、アルカリ土類金属、これらの窒化物およびこれらのホウ窒化物の総モル数を０．３〜２０部とすることを特徴とする請求項１〜１１の何れか１項に記載の立方晶窒化ホウ素の製造方法。And LiMBN 2, alkali metals, alkaline earth metals, the ratio of these nitrides and selected from the group consisting of boric nitride material, relative to 1 part of LiMBN 2 as moles, alkali metals, alkaline The cubic boron nitride according to any one of claims 1 to 11, wherein the total number of moles of the earth metal, these nitrides, and these boronitrides is 0.3 to 20 parts. Production method. 六方晶窒化ホウ素１００質量部に対し、触媒物質を５〜５０質量部の範囲内で含有させ、該含有物を立方晶窒化ホウ素の熱力学的安定領域内に保持して、六方晶窒化ホウ素を立方晶窒化ホウ素に変換する請求項１〜１２の何れか１項に記載の立方晶窒化ホウ素の製造方法。 With respect to 100 parts by mass of hexagonal boron nitride, the catalyst substance is contained in the range of 5 to 50 parts by mass, and the inclusion is held in the thermodynamic stability region of cubic boron nitride, producing how the cubic boron nitride according to any one of claims 1 to 12 to be converted to cubic boron nitride.
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JPWO2020049817A1 (en) * 2018-09-07 2020-09-10 昭和電工株式会社 Hexagonal boron nitride powder and its manufacturing method, as well as compositions and heat radiating materials using it.
CN110467469B (en) * 2019-08-28 2023-04-25 郑州中南杰特超硬材料有限公司 Preparation method of precursor for synthesizing polycrystalline cubic boron nitride
CN114014279B (en) * 2021-11-19 2023-02-28 郑州中南杰特超硬材料有限公司 Preparation method of porous polycrystalline cubic boron nitride

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