JPH0450273B2 - - Google Patents
Info
- Publication number
- JPH0450273B2 JPH0450273B2 JP57234742A JP23474282A JPH0450273B2 JP H0450273 B2 JPH0450273 B2 JP H0450273B2 JP 57234742 A JP57234742 A JP 57234742A JP 23474282 A JP23474282 A JP 23474282A JP H0450273 B2 JPH0450273 B2 JP H0450273B2
- Authority
- JP
- Japan
- Prior art keywords
- abrasive grains
- cbn
- boron nitride
- polycrystalline
- catalyst
- 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.)
- Expired - Lifetime
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- 239000006061 abrasive grain Substances 0.000 claims description 46
- 239000003054 catalyst Substances 0.000 claims description 25
- 229910052582 BN Inorganic materials 0.000 claims description 13
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 claims description 13
- 230000015572 biosynthetic process Effects 0.000 claims description 10
- 238000003786 synthesis reaction Methods 0.000 claims description 9
- 239000002245 particle Substances 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 230000000737 periodic effect Effects 0.000 claims description 3
- 238000010298 pulverizing process Methods 0.000 claims description 3
- 239000000470 constituent Substances 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims description 2
- 238000003825 pressing Methods 0.000 claims description 2
- 239000002184 metal Substances 0.000 claims 1
- 239000002904 solvent Substances 0.000 claims 1
- 239000013078 crystal Substances 0.000 description 19
- 238000000227 grinding Methods 0.000 description 18
- 238000000034 method Methods 0.000 description 12
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 238000005520 cutting process Methods 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 3
- 229910052796 boron Inorganic materials 0.000 description 3
- 229910052791 calcium Inorganic materials 0.000 description 3
- 238000003776 cleavage reaction Methods 0.000 description 3
- 229910052749 magnesium Inorganic materials 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 3
- 239000013081 microcrystal Substances 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 230000007017 scission Effects 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- 229910052712 strontium Inorganic materials 0.000 description 3
- 229910000760 Hardened steel Inorganic materials 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 150000004767 nitrides Chemical class 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 239000011164 primary particle Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- 229910000997 High-speed steel Inorganic materials 0.000 description 1
- -1 Mg 3 B 2 N 4 Chemical compound 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 description 1
- QZPSXPBJTPJTSZ-UHFFFAOYSA-N aqua regia Chemical compound Cl.O[N+]([O-])=O QZPSXPBJTPJTSZ-UHFFFAOYSA-N 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 229910000601 superalloy Inorganic materials 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
Description
(イ) 技術分野
本発明は研磨、研削用砥粒として利用される立
方晶型窒化硼素（CBN）の硬質砥粒及びその製
造法に関するものである。
(ロ) 技術の背景
立方晶型窒化硼素（以下CBNと記す）はダイ
ヤモンドに次ぐ硬度を有し、焼入鋼等の研磨、研
削用砥粒として広く使用されている。従来CBN
砥粒を製造する方法として用いられたのは六方晶
型窒化硼素（以下hBNと略す）を原料として、
これと周期律表ａ，ａ族元素（例えばLi，
Na，Ｋ，Mg，Ca，Sr）とその窒化物、又はこ
れ等元素と硼素、窒素の化合物、又はＡとFe，
Ni，Co，Si，Mn等の合金又はＡＮ等の触媒を
混合又は積層して超高圧、高温装置内に入れ、
CBNが安定な高圧、高温下でCBNに転換せしめ
るものであつた。例えば特公昭38−14号では
ａ，ａ族元素、鉛、アンチモン、錫又はこれ等
の窒化物を触媒とし、圧力50kb以上、温度1200
℃以上で３〜５分間処理することにより１〜
300μのCBN結晶が得られるとしている。また特
公昭57−43523では良質のCBN結晶をCaと硼素、
窒素の化合物である。
Ca3B2N4を触媒として用いることにより合成
する例が示されている。この方法では50kb，
1450℃〜2000℃の圧力、温度条件で10μ以上の不
純物の少い単結晶が60％もの収量で得られるとし
ている。
以上の方法により得られるCBN結晶はその殆
んどの粒子が単結晶からなるものであり、合成後
は触媒物質と未変換hBNのマトリツクス中に埋
め込まれて生成しているCBN単結晶をマトリツ
クスから分離する必要がある。通常触媒を王水等
で溶解除去し、更に未変換hBNを比重分離する
等の手法が用いられている。このようにして得ら
れたCBN粉末は通常60〜400メツシユの各粒度に
分級されて砥粒として使用される。
このような従来のCBN砥粒は焼入鋼等の硬い
鉄合金や超合金の研削加工に用いられている。
従来のこのCBN砥粒の欠点は粒度が粗くなる
にしたがつて破壊強度が著しく低下し、これを用
いた研削砥石の寿命が低いことであつた。これを
改良するために近年極めて微細なCBN微結晶を
焼結した多結晶CBN砥粒が提案されている。こ
れは多結晶体とすることによつてCBN結晶の劈
開による破損を食い止め破壊強度を上げようとす
る考えに基くものである。
例えば特開昭55−167110号には気相合成により
得られた熱分解六方晶型窒化硼素を用いて合成触
媒を使用せず直接65〜70kb，1900〜2500℃の高
圧、高温を加えてこれをCBN多結晶体に転換せ
しめ、この焼結体を粉砕して多結晶質砥粒を得る
方法が開示されている。
触媒を使用しないためこの方法で得られる多結
晶砥粒の個々のCBN一次粒子は極めて微細であ
る。同号証に引用されている先例米国出願第
812283号（特開昭54−33510に対応する）によれ
ばこの一次微結晶のサイズは約1000〓（0.1μ）の
オーダーであるとされている。このような微細結
晶の集合体からなる多結晶砥粒は粒としての破壊
強度が単結晶砥粒より著しく改善されるが、あま
りに強度が高すぎるため研削時に砥粒として重要
な特性である砥粒の劈開による自生刃先生成が少
くなり切れ味が低下するという欠点を有する。砥
粒として理想的なものは適度の強度を有し、有効
な切刃が摩耗した時点で微細な破壊により次の刃
先が自生することである。本願はこのような特性
を有するCBN砥粒の合成を目標として種々検討
した結果得られたものである。
(ハ) 発明の開示
CBN単結晶砥粒では劈開性が強く、強度面の
改良には限界がある。多結晶砥粒では前述の如く
切刃の自生作用が劣るが、本発明では従来の多結
晶砥粒とは異なつた製法により合成実験を行なつ
て検討した結果、多結晶砥粒の一次粒子サイズが
粗くなるとこの欠点が改良されることを見出し
た。
本発明の多結晶CBN砥粒はhBNとCBN合成触
媒の所定量の混合物を圧力40〜60kb、温度1350
℃〜1800℃に加圧、加熱処理してhBN→CBNの
変換と同時にこれを焼結せしめ、更にこの焼結体
を粉砕することで製造するものである。前記した
従来のCBN多結晶砥粒の製法では触媒を用いず
に変換率を高めるため熱分解六方晶型窒化硼素を
原料としているが、この方法では100％近い変換
率を得るためには極めて高い圧力、温度で処理す
る必要がある。また前記した如く触媒を用いない
ために変換したCBN一次結晶も極めて微細であ
る。
本発明の多結晶砥粒は通常のhBNに触媒とし
てMg，Ca，Sr等の周期律表ａ族元素の硼窒化
物を容積で１〜10％均一に混合したものを原料と
して使用する。触媒として用いるものは従来の単
結晶CBN砥粒を合成するために用いられている
ものの中から選択したものである。尚触媒は上記
の１種を単独で又は２種以上を用いても良い。従
来の単結晶砥粒合成では触媒の混合量は通常体積
で20％以上であり、当然のことながら生成した
CBN単結晶が相互に結合して集合体とならない
ようにhBN及び触媒がCBN粒子のマトリツクス
として周囲に存在するように合成されていた。本
発明では用いる原料hBNの殆んどをCBNに転換
せしめるもので、このために必要最小限の触媒を
使用する。
触媒としては前述のものを用いるが、中でも
Mg，Ca，Sr，Ba等のアルカリ土類金属と硼素、
窒素との化合物、例えばMg3B2N4，Ca3B2N4，
Sr3B2N4，Ba3B2N4を用いるとhBNに対し５容
量％以下の添加で100％の変換率を得ることがで
きる。
また合成条件も圧力45〜55kb、温度1350〜
1500℃で目的とする一次結晶粒度が1μ以上に発
達した多結晶体を容易に得ることができた。この
ような方法で製造した焼結体中には触媒構成物質
が残留するが実験によると添加して全量が残留す
るのではなく、変換、焼結反応時に焼結対外周部
に溶出するため、焼結体中へはその一部が残留し
ていた。
本発明の多結晶砥粒は原理的に巾広い粒度のも
のが製造できる。一般的に使用される粒度は16メ
ツシユ以下、400メツシユ以上である。また本発
明の多結晶砥粒中に残留する触媒構成物質の量は
５容積％を越えると砥粒の強度が充分でなく、ま
た0.1％未満にするには触媒の添加量が少なすぎ
るため、CBN多結晶中に六方晶型窒化硼素が残
留するため好ましくない。
以下実施例により更に具体的に記す。
実施例 １
hBN粉末とMg3N2の混合粉を窒素雰囲気中で
処理してMg3B2N4粉末を合成し、これを触媒と
して用いた。hBN粉末97容積％、Mg3B2N4３容
積％を均一に混合した後、2t／cm2で10mmφ、高さ
２mmに型押成型した。
この成型体３枚を超高圧、高温発生装置に入
れ、圧力50kb、温度1450℃で５分間保持後取出
した。得られた円板をＸ線回折により調べたとこ
ろCBNの回折ピーク以外は見られなかつた。又
Ｘ線マイクロアナライザーで調べた結果Mgが少
量存在していた。
このMgは恐らくMg3N2の形の化合物と考えら
れる。化学分析の結果Mgの残存量は0.3重量％で
あつた。CBN結晶の粒度は焼結体の破面を走査
型電子顕微鏡で観察して測定したところ平均5μ
であつた。このCBN焼結体円板を更に多数個作
成し、これを機械的に粉砕して篩分し砥粒とし
た。この砥粒表面に55重量％のNiをメツキした。
メツキした砥粒を更に篩分して60/80メツシユの
ものを用いて性能試験を行なつた。この砥粒でレ
ジンボンドのカツプ砥石を製作した。砥石径は
100mm、集中度75とした。比較のために同一の砥
石を市販の単結晶CBNにNiメツキを施した砥粒
を用いて製作した。被削材として高速度鋼SKH
−９（HRc62）を用い周速1160ｍ／分、テーブル
速度2.6ｍ／分、切り込み0.05mm／パスで試験し
た。
結果は本発明による多結晶砥粒を用いた砥石で
は研削比360で従来の単結晶砥粒を用いたもので
は研削比100であつた。
実施例 ２
触媒としてCa3B2N4を用いた他は実施例１と
同様にしてCBN焼結体を得た。
これを粉砕してNiメツキを行ない80/120、メ
ツシユの砥粒を製作した。尚多結晶砥粒中の一次
結晶サイズは約10μであつた。比較のために触媒
を用いずに製造された市販の多結晶砥粒を使用し
た。
実施例１と同様のカツプ砥石をこの２種の砥粒
を用いて製作し、実施例１と同一条件で研削荷重
を一定にした定圧研削法により被加工材の一定量
を加工するに要した時間で研削能力を比較した。
被加工材はSKH−９（HRc62）で研削体積２c.c.の
場合、研削荷重30Kgでは本発明の砥粒を用いた砥
石では25秒で加工できたのに対し、市販多結晶砥
粒では１分を要した。砥石を観察すると後者は砥
粒の目つぶれが多く見られた。
実施例 ３
六法晶型窒化硼素を原粒とし以下の触媒配合組
成でCBN多結晶体を得た。
(a) Technical field The present invention relates to cubic boron nitride (CBN) hard abrasive grains used as abrasive grains for polishing and grinding, and a method for producing the same. (b) Background of the technology Cubic boron nitride (hereinafter referred to as CBN) has a hardness second only to diamond, and is widely used as an abrasive grain for polishing and grinding hardened steel. Conventional CBN
The method used to manufacture abrasive grains was to use hexagonal boron nitride (hereinafter abbreviated as hBN) as a raw material.
In addition to this, elements of group a and a of the periodic table (e.g. Li,
Na, K, Mg, Ca, Sr) and their nitrides, or compounds of these elements with boron, nitrogen, or A and Fe,
Alloys such as Ni, Co, Si, Mn, etc. or catalysts such as AN are mixed or stacked and placed in an ultra-high pressure, high temperature device.
CBN was converted to CBN under stable high pressure and high temperature. For example, in Special Publication No. 38-14, a group A, a group element, lead, antimony, tin, or a nitride of these is used as a catalyst, and the pressure is 50 kb or more and the temperature is 1200 kb.
1 to 5 minutes by processing at temperatures above ℃
It is said that 300μ CBN crystals can be obtained. In addition, in the Special Publication No. 57-43523, high quality CBN crystal was used to combine Ca and boron.
It is a compound of nitrogen. An example of synthesis using Ca 3 B 2 N 4 as a catalyst is shown. In this method, 50kb,
It is said that under pressure and temperature conditions of 1,450°C to 2,000°C, single crystals with a size of 10μ or more with few impurities can be obtained at a yield of 60%. Most of the particles of the CBN crystals obtained by the above method are composed of single crystals, and after synthesis, the CBN single crystals embedded in the matrix of the catalyst material and unconverted hBN are separated from the matrix. There is a need to. Usually, a method is used in which the catalyst is dissolved and removed using aqua regia, etc., and then unconverted hBN is separated by specific gravity. The CBN powder thus obtained is usually classified into particle sizes of 60 to 400 mesh and used as abrasive grains. Such conventional CBN abrasive grains are used for grinding hard iron alloys and superalloys such as hardened steel. The disadvantage of conventional CBN abrasive grains is that as the grain size becomes coarser, the fracture strength decreases significantly, and the life of a grinding wheel using it is short. To improve this, polycrystalline CBN abrasive grains made by sintering extremely fine CBN microcrystals have recently been proposed. This is based on the idea that by forming the CBN crystal into a polycrystalline material, damage caused by cleavage of the CBN crystal can be prevented and fracture strength can be increased. For example, in JP-A No. 55-167110, pyrolytic hexagonal boron nitride obtained by vapor phase synthesis was used to directly produce 65 to 70 kb without using a synthesis catalyst, and by applying high pressure and high temperature of 1900 to 2500℃. A method for obtaining polycrystalline abrasive grains by converting CBN into polycrystalline CBN and pulverizing this sintered body is disclosed. Since no catalyst is used, the individual CBN primary particles of the polycrystalline abrasive grains obtained by this method are extremely fine. Preceding U.S. Application No. cited in the same document
According to No. 812283 (corresponding to JP-A No. 54-33510), the size of this primary microcrystal is on the order of about 1000㎓ (0.1μ). Polycrystalline abrasive grains, which are made up of aggregates of microcrystals, have significantly improved fracture strength as grains compared to single-crystal abrasive grains, but their strength is too high, which is an important characteristic of abrasive grains during grinding. The disadvantage is that the formation of a natural cutting edge due to cleavage is reduced, resulting in a decrease in sharpness. The ideal abrasive grain is one that has appropriate strength, and when the effective cutting edge wears out, the next cutting edge grows by itself through minute fractures. The present application was obtained as a result of various studies aimed at synthesizing CBN abrasive grains having such characteristics. (C) Disclosure of the Invention CBN single-crystal abrasive grains have strong cleavage properties, and there is a limit to improvement in strength. As mentioned above, polycrystalline abrasive grains are inferior in self-growth of cutting edges, but in the present invention, as a result of conducting synthesis experiments using a manufacturing method different from conventional polycrystalline abrasive grains, we found that the primary particle size of polycrystalline abrasive grains is It has been found that this defect can be improved by making the surface rougher. The polycrystalline CBN abrasive grains of the present invention are produced by mixing a predetermined amount of hBN and CBN synthesis catalyst at a pressure of 40 to 60 kb and a temperature of 1350 kb.
It is manufactured by applying pressure and heat treatment to a temperature of 1800°C to 1800°C to simultaneously convert hBN to CBN and sintering it, and then pulverizing this sintered body. The conventional manufacturing method for CBN polycrystalline abrasive grains described above uses pyrolytic hexagonal boron nitride as a raw material in order to increase the conversion rate without using a catalyst. It is necessary to process with pressure and temperature. Furthermore, as mentioned above, the converted CBN primary crystals are extremely fine because no catalyst is used. The polycrystalline abrasive grains of the present invention are made by uniformly mixing 1 to 10% by volume of normal hBN with boronitrides of Group A elements of the periodic table such as Mg, Ca, and Sr as catalysts. The catalyst used was selected from those used to synthesize conventional single-crystal CBN abrasive grains. In addition, the above-mentioned catalyst may be used alone or in combination of two or more. In conventional single-crystal abrasive grain synthesis, the amount of catalyst mixed is usually 20% or more by volume, and naturally
In order to prevent the CBN single crystals from bonding together and forming aggregates, hBN and the catalyst were synthesized so that they existed as a matrix of CBN particles around them. In the present invention, most of the raw material hBN used is converted into CBN, and for this purpose, the minimum necessary catalyst is used. The catalysts mentioned above are used, but among them
Alkaline earth metals such as Mg, Ca, Sr, Ba and boron,
Compounds with nitrogen, such as Mg 3 B 2 N 4 , Ca 3 B 2 N 4 ,
When Sr 3 B 2 N 4 and Ba 3 B 2 N 4 are used, a conversion rate of 100% can be obtained by adding 5% by volume or less to hBN. Also, the synthesis conditions are pressure 45-55kb, temperature 1350-
At 1500℃, it was possible to easily obtain a polycrystal with a primary crystal grain size of 1μ or more. Catalyst constituent substances remain in the sintered body produced by this method, but experiments have shown that the entire amount does not remain after being added, but rather dissolves into the outer periphery of the sintered body during the conversion and sintering reactions. A part of it remained in the sintered body. In principle, the polycrystalline abrasive grains of the present invention can be produced in a wide range of particle sizes. Generally used particle sizes are below 16 mesh and above 400 mesh. Furthermore, if the amount of the catalyst component remaining in the polycrystalline abrasive grains of the present invention exceeds 5% by volume, the strength of the abrasive grains will not be sufficient, and if it is less than 0.1%, the amount of catalyst added is too small. This is not preferred because hexagonal boron nitride remains in the CBN polycrystal. The following will be described in more detail with reference to Examples. Example 1 A mixed powder of hBN powder and Mg 3 N 2 was treated in a nitrogen atmosphere to synthesize Mg 3 B 2 N 4 powder, which was used as a catalyst. After uniformly mixing 97% by volume of hBN powder and 3% by volume of Mg 3 B 2 N 4 , it was pressed and molded at 2t/cm 2 to a size of 10 mmφ and 2 mm in height. Three of these molded bodies were placed in an ultra-high pressure and high temperature generator, held at a pressure of 50 kb and a temperature of 1450°C for 5 minutes, and then taken out. When the obtained disk was examined by X-ray diffraction, no diffraction peak other than CBN was observed. Also, as a result of examination with an X-ray microanalyzer, a small amount of Mg was present. This Mg is probably a compound in the form of Mg 3 N 2 . As a result of chemical analysis, the residual amount of Mg was 0.3% by weight. The average grain size of CBN crystals was 5μ when measured by observing the fracture surface of the sintered body with a scanning electron microscope.
It was hot. A larger number of these CBN sintered disks were made, and they were mechanically crushed and sieved to obtain abrasive grains. The surface of this abrasive grain was plated with 55% by weight Ni.
The plated abrasive grains were further sieved and a performance test was conducted using 60/80 mesh. Using this abrasive grain, I made a resin bonded Katsupu whetstone. The diameter of the grinding wheel is
100mm, concentration level 75. For comparison, the same grinding wheel was manufactured using commercially available single crystal CBN with Ni-plated abrasive grains. High speed steel SKH as work material
-9 (HRc62), the test was conducted at a circumferential speed of 1160 m/min, a table speed of 2.6 m/min, and a cutting depth of 0.05 mm/pass. The results showed that the grinding wheel using polycrystalline abrasive grains according to the present invention had a grinding ratio of 360, and the grinding wheel using conventional single crystal abrasive grains had a grinding ratio of 100. Example 2 A CBN sintered body was obtained in the same manner as in Example 1 except that Ca 3 B 2 N 4 was used as a catalyst. This was crushed and Ni-plated to produce 80/120 and mesh abrasive grains. The primary crystal size in the polycrystalline abrasive grains was approximately 10μ. For comparison, commercially available polycrystalline abrasive grains produced without catalyst were used. A cup grinding wheel similar to that in Example 1 was manufactured using these two types of abrasive grains, and the amount required to process a certain amount of the workpiece by the constant pressure grinding method with a constant grinding load under the same conditions as in Example 1 was calculated. Grinding ability was compared based on time.
When the workpiece is SKH-9 (HRc62) and the grinding volume is 2 c.c., the grinding wheel using the abrasive grains of the present invention could process the material in 25 seconds at a grinding load of 30 kg, whereas the commercially available polycrystalline abrasive grains could process it in 25 seconds. It took 1 minute. When observing the whetstone, it was found that the abrasive grains of the latter were often crushed. Example 3 A CBN polycrystalline body was obtained using hexagonal boron nitride as raw particles and the following catalyst composition.
【表】
この多結晶体を粉砕して60/80メツシユサイズ
の砥粒を得た。[Table] This polycrystal was crushed to obtain abrasive grains of 60/80 mesh size.
Claims (1)
表ａ族金属の硼窒化物が容積比で各々90〜99：
10〜１の割合である混合物を立方晶型窒化硼素の
熱力学的安定領域の圧力、温度範囲で圧力40〜60
Kb、温度1350〜1800℃にて加圧、加熱して六方
晶型窒化硼素を1μ以上10μ以下の立方晶型窒化硼
素に変換すると同時に溶媒構成物質を0.1〜５容
量％含んだ状態で多結晶体に転換せしめ、これを
取り出した後粉砕して所定の粒度の多結晶型窒化
硼素砥粒にすることを特徴とする硬質砥粒の製造
法。1 Hexagonal boron nitride and boronitride, a metal of group A of the periodic table, as a synthesis catalyst, each in a volume ratio of 90 to 99 :
A mixture having a ratio of 10 to 1 is heated to a pressure in the thermodynamic stability region of cubic boron nitride, and a temperature range of 40 to 60 .
Kb, convert hexagonal boron nitride into cubic boron nitride with a size of 1μ to 10μ by applying pressure and heating at a temperature of 1350 to 1800℃, and at the same time converting it into polycrystals containing 0.1 to 5% by volume of solvent constituents. A method for producing hard abrasive grains, which is characterized by converting the abrasive grains into polycrystalline boron nitride abrasive grains, taking them out, and pulverizing them into polycrystalline boron nitride abrasive grains having a predetermined particle size.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57234742A JPS59121167A (en) | 1982-12-27 | 1982-12-27 | Hard grinding grain and manufacture |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57234742A JPS59121167A (en) | 1982-12-27 | 1982-12-27 | Hard grinding grain and manufacture |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59121167A JPS59121167A (en) | 1984-07-13 |
| JPH0450273B2 true JPH0450273B2 (en) | 1992-08-13 |
Family
ID=16975643
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57234742A Granted JPS59121167A (en) | 1982-12-27 | 1982-12-27 | Hard grinding grain and manufacture |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59121167A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2177585B1 (en) * | 2003-08-20 | 2014-11-26 | Showa Denko K.K. | Cubic boron nitride, method for producing cubic boron nitride, grinding wheel with cubic boron nitride, and sintered cubic boron nitride compact |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5320480A (en) * | 1976-08-06 | 1978-02-24 | Nakajima Sakao | Photosynthesis utilizing culture medium particle |
| JPS5347239A (en) * | 1976-10-13 | 1978-04-27 | Nippon Telegr & Teleph Corp <Ntt> | Characteristic extraction method |
| JPS56140014A (en) * | 1980-03-31 | 1981-11-02 | Showa Denko Kk | Synthesizing method for cubic system boron nitride |
| JPS57149899A (en) * | 1981-03-06 | 1982-09-16 | Natl Inst For Res In Inorg Mater | Manufacture of cubic system boron nitride |
| JPS58199706A (en) * | 1982-05-14 | 1983-11-21 | ベロルススキ−・ポリチエフニチエスキ−・インスチツ−ト | Manufacture of polycrystal of cubic boron nitride |
-
1982
- 1982-12-27 JP JP57234742A patent/JPS59121167A/en active Granted
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5320480A (en) * | 1976-08-06 | 1978-02-24 | Nakajima Sakao | Photosynthesis utilizing culture medium particle |
| JPS5347239A (en) * | 1976-10-13 | 1978-04-27 | Nippon Telegr & Teleph Corp <Ntt> | Characteristic extraction method |
| JPS56140014A (en) * | 1980-03-31 | 1981-11-02 | Showa Denko Kk | Synthesizing method for cubic system boron nitride |
| JPS57149899A (en) * | 1981-03-06 | 1982-09-16 | Natl Inst For Res In Inorg Mater | Manufacture of cubic system boron nitride |
| JPS58199706A (en) * | 1982-05-14 | 1983-11-21 | ベロルススキ−・ポリチエフニチエスキ−・インスチツ−ト | Manufacture of polycrystal of cubic boron nitride |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59121167A (en) | 1984-07-13 |
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