CN1200908C - Method for producing cubic boron nitride and product obtained through the method - Google Patents

Method for producing cubic boron nitride and product obtained through the method Download PDF

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CN1200908C
CN1200908C CN 02801387 CN02801387A CN1200908C CN 1200908 C CN1200908 C CN 1200908C CN 02801387 CN02801387 CN 02801387 CN 02801387 A CN02801387 A CN 02801387A CN 1200908 C CN1200908 C CN 1200908C
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boron nitride
cubic boron
nitride
alkaline
catalyst substance
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CN1462260A (en
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饭塚诚
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Resonac Holdings Corp
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Showa Denko KK
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Abstract

A method for producing cubic boron nitride includes maintaining hexagonal boron nitride in the presence of a catalyst substance under conditions where cubic boron nitride remains thermodynamically stable to thereby transform hexagonal boron nitride into cubic boron nitride, wherein the catalyst substance contains LiMBN2, in which M represents Ca, Sr, Ba, Ra, Be, or Mg, and at least one species selected from the group consisting of alkali metals, alkaline earth metals, nitrides thereof and boronitrides thereof. Any one of the LiMBN2, alkali metals, alkaline earth metals, nitrides thereof and boronitrides thereof has an oxygen content of 1 % or less. As a result, the percent transformation into cubic boron nitride can be considerably enhanced, and the cubic boron nitride obtained exhibits high mechanical strength.

Description

Produce the method for cubic boron nitride and the product that obtains with this method
The cross reference of related application
The application is based on that the regulation of 35U.S.C. the 111st (a) bar submits, enjoy U.S. Provisional Application 60/280 according to 35U.S.C. the 119th (e) (1) bar, the rights and interests of 749 the applying date, this provisional application are according to submitting the April 3 calendar year 2001 that is specified in of 35U.S.C. the 111st (b) bar.
Technical field
The present invention relates to a kind of method of producing cubic boron nitride, with cubic boron nitride and a kind of grinding stone that forms by this cubic boron nitride of this method acquisition by hexagonal boron nitride.
Background technology
The hardness of cubic boron nitride is only second to diamond and chemical stability is better than diamond.Therefore, cubic boron nitride is more and more widely as abrasive substance, polishing material and cutting material.The method of having proposed multiple production cubic boron nitride at present.Wherein, the most famous and by the most widely used method be: in the presence of catalyst substance at industrial circle, place cubic boron nitride to keep under the thermodynamically stable condition (about 4.0-6.0Gpa and about 1400-1600 ℃) hexagonal boron nitride, thereby change hexagonal boron nitride into cubic boron nitride.United States Patent (USP) 3,772,428 and JP-B SHO 61-283, JP-B HEI5-94 and JP-B HEI 5-95 open, basic metal, alkaline-earth metal and nitride thereof and nitrogen boride all can be used as catalyst substance.Or rather, United States Patent (USP) 3,772,428 open Li 3N and Li 3BN 2Be promising especially catalyst substance.Yet it is 50 μ m or littler and comprise the particulate form of the crystal face of fully not growing up that the cubic boron nitride that uses above-mentioned any catalyst substance to produce presents particle diameter usually.Therefore, the abrasive material of being produced by these cubic boron nitrides does not also have satisfied performance.
The open LiCaBN of JP-B SHO 61-283 2Be the most promising catalyst substance.Use the cubic boron nitride of this catalyst substance production to be semisphere usually and to have excellent physical strength.JP-BHEI 5-94 and JP-B HEI 5-95 disclose a kind of method, wherein with LiMBN 2(M represents alkaline-earth metal) and Li 8SiN 4Or Ca 5Si 2N 6Mixture as catalyst substance.The cubic boron nitride that uses this method to produce has (111) crystal face of growing up fully and has excellent mechanical property.
Yet these methods all do not obtain the transformation efficiency that gratifying hexagonal boron nitride transforms to cubic boron nitride.Therefore, in commercial run, need a kind of catalyst substance that can realize high conversion.And catalyst substance also needs to have higher physical strength.
One of purpose of the present invention is to solve the problem that exists in the above-mentioned conventional art, and the grinding stone that provides improved cubic boron nitride of physical strength and nonferromagnetic substance to be enhanced.
Another object of the present invention is to provide a kind of method of producing cubic boron nitride, and this method has improved the transformation efficiency that hexagonal boron nitride is converted into cubic boron nitride.
Summary of the invention
The present invention relates to a kind of method of producing cubic boron nitride, this method is included in catalyst substance and exists down, place cubic boron nitride to keep under the thermodynamically stable condition hexagonal boron nitride, thereby hexagonal boron nitride is converted into cubic boron nitride, catalyst substance wherein contains LiMBN 2With at least a material that is selected from basic metal, alkaline-earth metal and nitride thereof and nitrogen boride, LiMBN 2In M represent Ca, Sr, Ba, Ra, Be or Mg.
LiMBN 2, any one oxygen level is 1% or lower in basic metal, alkaline-earth metal and nitride and the nitrogen boride.
LiMBN 2Be LiCaBN 2Or LiBaBN 2
Alkali-metal nitride comprises the nitride of Na, K, Rb, Cs and Fr, and the nitride of alkaline-earth metal comprises the nitride of Ra, Be and Mg.
Alkali-metal nitrogen boride comprises Li 3BN 2, the nitrogen boride of alkaline-earth metal comprises Ca 3B 2N 4And Mg 3B 2N 4
Catalyst substance preferably contains LiCaBN 2And Li 3BN 2
LiMBN based on 1 molar part 2, at least a amount of substance that is selected from basic metal, alkaline-earth metal and nitride thereof and nitrogen boride is the 0.3-20 molar part.
The catalyst substance that adds the 5-50 mass parts in the hexagonal boron nitride of 100 mass parts forms mixture, places cubic boron nitride to keep under the thermodynamically stable condition in this mixture then, thereby hexagonal boron nitride is converted into cubic boron nitride.
The invention still further relates to cubic boron nitride that uses this method production and the grinding stone of producing with this cubic boron nitride.
The method of cubic boron nitride produced according to the invention, hexagonal boron nitride far surpasses 50% to the transformation efficiency that cubic boron nitride transforms, and the transformation efficiency of ordinary method is about 30%.And because the cubic boron nitride that obtains shows the shape anisotropy of height, so its physical strength is improved.Compare with traditional grinding stone, have quite excellent nonferromagnetic substance by the grinding stone of this cubic boron nitride production.
Brief Description Of Drawings
Fig. 1 is used for hexagonal boron nitride is converted into the sectional schematic diagram of the reactor of cubic boron nitride.
Implement best mode of the present invention
The present invention relates to a kind of method of producing cubic boron nitride, be included in catalyst substance and exist down, place cubic boron nitride to keep under the thermodynamically stable condition hexagonal boron nitride, thereby hexagonal boron nitride is converted into cubic boron nitride.In implementing a kind of mode of production method of the present invention, hexagonal boron nitride powder and catalyst substance mix, (the 1-2t/cm for example of pressurization then 2Pressure) mixture is pressed into briquetting.Briquetting is put into the container that is equipped with extremely-high tension generator, and keep (about 4-6Gpa under the thermodynamically stable condition at cubic boron nitride, about 1600 ℃ of about 1400-) places preset time (1 second-6 hours according to appointment), thereby hexagonal boron nitride is converted into cubic boron nitride.After the conversion, from extremely-high tension generator, take out synthetic blank thus, from blank, separate cubic boron nitride and purification then.
In the present invention, can use commercial hexagonal boron nitride powder as the hexagonal boron nitride raw material.Yet, preferably using the low hexagonal boron nitride powder of oxygen level, this is to hinder hexagonal boron nitride usually because of the oxygen impurities with oxide form such as boron oxide migration to transform to cubic boron nitride.Especially, preferably using oxide content is 1% or lower hexagonal boron nitride powder.About the particle diameter of hexagonal boron nitride powder, preferred maximum particle diameter is 100 μ m or littler.Particle diameter is excessive to be not preferred, and this is because particle diameter is crossed the reactivity that senior general destroys hexagonal boron nitride and catalyst substance, thereby causes hexagonal boron nitride to reduce to the transformation efficiency that cubic boron nitride transforms.
The catalyst substance that the present invention uses contains LiMBN 2(be different from LiMBN with at least a material that is selected from basic metal, alkaline-earth metal and nitride thereof and nitrogen boride 2).LiMBN 2In symbol " M " represent Ca, Sr, Ba, Ra, Be or Mg.Wherein, Ca and Ba are for preferred especially.And, the LiMBN that oxygen impurities content is low 2Be preferred.Particularly, LiMBN 2Preferably have 1% or littler oxygen level, more preferably 0.5% or littler.Oxygen impurities is not preferred, and this is to transform to cubic boron nitride because it hinders hexagonal boron nitride.
Though not to LiMBN 2Particle diameter limit especially, but generally speaking, preferred maximum particle diameter is 100 μ m or littler.Particle diameter is excessive to be not preferred, and this is because particle diameter is crossed senior general and destroyed LiMBN 2With the reactivity of hexagonal boron nitride, thereby cause hexagonal boron nitride to reduce to the transformation efficiency that cubic boron nitride transforms.
Below will be with LiCaBN 2Be example, synthetic LiMBN used in the present invention is described in detail in detail 2Method.At first, with the powder of lithium nitride, CaCl2 and hexagonal boron nitride as raw material.With these powder according to (lithium nitride): (CaCl2): (hexagonal boron nitride) is that 1: 1: 3 constitutive molar ratio mixes.Mixture is placed in rare gas element such as nitrogen or the argon gas atmosphere, in about 1000 ℃ of insulations 40 minutes, cooling then, thus obtain LiCaBN 2Solid.In inert gas atmosphere, with LiCaBN 2Solid grinds to make LiCaBN 2Powder.
The catalyst substance that the present invention uses must contain LiMBN 2With at least a material that is selected from basic metal, alkaline-earth metal and nitride thereof and nitrogen boride.The nitride of selected basic metal or alkaline-earth metal and nitrogen boride must be different from the LiMBN that contains in the catalyst substance 2
Especially, basic metal comprises Li, Na, K, Rb, Cs and Fr.Especially when using Li, can produce cubic boron nitride by higher transformation efficiency with excellent mechanical strength.
The example of alkaline-earth metal comprises Ca, Sr, Ba, Ra, Be and Mg.Especially when using Ca or Mg, can produce cubic boron nitride by higher transformation efficiency with excellent mechanical strength.
The example of alkali metal nitride comprises Li 3N, Na 3N, K 3N, Rb 3N, Cs 3N and Fr 3N.Especially when using Na 3N, K 3N, Rb 3N, Cs 3N or Fr 3During N, can produce cubic boron nitride by higher transformation efficiency with excellent mechanical strength.
The example of alkaline-earth nitride comprises Ca 3N 2, Sr 3N 2, Ba 3N 2, Ra 3N 2, Be 3N 2And Mg 3N 2Especially when using Ra 3N 2, Be 3N 2Or Mg 3N 2The time, can produce cubic boron nitride by higher transformation efficiency with excellent mechanical strength.
The example of basic metal nitrogen boride comprises Li 3BN 2, Na 3BN 2, K 3BN 2, Rb 3BN 2, Cs 3BN 2And Fr 3BN 2Especially when using Li 3BN 2The time, can produce cubic boron nitride by higher transformation efficiency with excellent mechanical strength.
The example of alkaline-earth metal nitrogen boride comprises Ca 3B 2N 4, Sr 3B 2N 4, Ba 3B 2N 4, Ra 3B 2N 4, Be 3B 2N 4And Mg 3B 2N 4Especially when using Ca 3B 2N 4Or Mg 3B 2N 4The time, can produce cubic boron nitride by higher transformation efficiency with excellent mechanical strength.
Be used for basic metal of the present invention, alkaline-earth metal and nitride thereof and nitrogen boride and preferably have low impurity concentration.Especially the oxygen that exists as impurity causes serious retroaction.Therefore, oxygen impurities content preferably is controlled at 1% or lower, more preferably is controlled at 0.5% or lower.Be higher than 1% oxygen level and will destroy the degree of crystallinity of the cubic boron nitride of being produced.
The particle diameter that is used for basic metal of the present invention, alkaline-earth metal and nitride thereof and nitrogen boride is not particularly limited.But because excessive particle diameter destroys the reactivity of above-mentioned substance and hexagonal boron nitride, therefore, the maximum particle diameter of above-mentioned substance generally is preferably 100 μ m or littler.
The catalyst substance that uses among the present invention especially preferably comprises LiCaBN 2Combination with one of following substances: Li, Ca, Mg, Na 3N, K 3N, Rb 3N, Cs 3N, Fr 3N, Ra3N 2, Be3N 2, Mg 3N 2, Li 3BN 2, Ca 3B 2N 4And Mg 3B 2N 4In these combinations, most preferably use LiCaBN 2And Li 3BN 2Combination.When using this combination, can produce cubic boron nitride by the highest transformation efficiency with excellent mechanical strength.
In the present invention, to comprising at least a amount of substance and the LiMBN that is selected from basic metal, alkaline-earth metal and nitride thereof and nitrogen boride 2The ratio of amount control.Particularly, based on 1 molar part LiMBN 2, the total amount of employed basic metal, alkaline-earth metal and nitride thereof and nitrogen boride is preferably the 0.3-20 molar part, more preferably the 0.3-10 molar part.When the total amount of basic metal, alkaline-earth metal and nitride thereof and nitrogen boride during, just can not bring into play the effect of these compounds fully, and hexagonal boron nitride reduces to the transformation efficiency that cubic boron nitride transforms less than 0.3 molar part; Otherwise when its total amount surpassed 20 molar part, the rate of formation of cubic boron nitride was increased sharply, thereby has destroyed physical strength and shape facility, and the result causes the abrasive material mis-behave.
By mixing LiMBN 2Powder and at least a material powder that is selected from basic metal, alkaline-earth metal and nitride thereof and nitrogen boride prepare above-mentioned catalyst substance.Alternatively, catalyst substance can prepare as follows: with mix than blended basic metal, alkaline-earth metal and nitride thereof according to predetermined composition, then in rare gas element such as nitrogen or argon gas with the gained mixture in for example 700-1200 ℃ of down heating.
The present invention uses LiMBN 2With at least a material of basic metal, alkaline-earth metal and nitride thereof and nitrogen boride that is selected from as catalyst substance.These materials and hexagonal boron nitride are mixed, and place cubic boron nitride to keep under the thermodynamically stable condition in the gained mixture, thereby hexagonal boron nitride is converted into cubic boron nitride.Alternatively, will mix with hexagonal boron nitride, place cubic boron nitride to keep under the thermodynamically stable condition in the mixture that obtains then as the material of basic metal, alkaline-earth metal and nitride thereof or boron nitride, and this stage with LiMBN 2Sneak in this mixture with at least a material that is selected from basic metal, alkaline-earth metal and nitride thereof and nitrogen boride.
About above-mentioned catalyst substance usage ratio in the present invention, the preferred catalyst substance that adds the 5-50 mass parts, the more preferably catalyst substance of 10-30 mass parts in the hexagonal boron nitride of 100 mass parts.If the consumption of catalyst substance is less than 5 mass parts or surpass 50 mass parts, the physical strength of the cubic boron nitride of Xing Chenging and shape facility will worsen so, thereby cause the performance depreciation by the abrasive substance of cubic boron nitride production.
For catalyst substance and hexagonal boron nitride preparation process of mixture, preferably together with its powder mixes.As selection, hexagonal boron nitride layer and catalyst substance layer alternately can be deposited in the reactor.Or rather, in a preferred scheme with hexagonal boron nitride with catalyst substance mixes or respectively at 1-2t/cm 2Forming under the pressure, then the mixture or the briquetting that obtain are put into reactor.By making in this way, the handlability of raw material powder is improved, and incites somebody to action under the shrinking percentage of raw material in reactor, thereby boosts productivity.
In another optional method, in advance cubic boron nitride seed crystal is joined in said mixture or the briquetting, thereby be the growth that nucleus promotes cubic boron nitride with the crystal seed.Need not query, this method also within the scope of the invention.In this case, seed surface can the coated catalysts material.
Above-mentioned briquetting is put into reactor, and reactor is put into a known high temp/high pressure producer, briquetting is remained under certain temperature/pressure condition, cubic boron nitride is in thermodynamics stable state under this condition.About stability condition of thermodynamics referring to O.Fukunaga at Diamond Relat.Mater., 9, (2000), the description of 7-12 page or leaf.Have no particular limits for the hold-time of briquetting under this condition, the hold-time is generally 1 approximately second by 6 hours.
By briquetting is remained under the stability condition of thermodynamics, hexagonal boron nitride is converted into cubic boron nitride.A kind of synthetic blank that contains hexagonal boron nitride, cubic boron nitride and catalyst substance of general generation.In order to separate and the purification cubic boron nitride, with the synthetic blank fragmentation that generates thus.Can use separation and the method for purification described among the JP-BSHO 49-27757.One of method is: the synthetic blank that will generate is broken into and is of a size of 5mm or littler particle, and adds sodium hydroxide and a spot of water in particle.Then with mixture heating up to about 320 ℃ optionally to dissolve hexagonal boron nitride.Then mixture is cooled off, undissolved material of pickling and filtering separation, thus obtain cubic boron nitride.
Thus obtained cubic boron nitride is carried out classification according to the particle diameter grade of JIS-B4130 regulation.The particle diameter grade is that 100/120 boron nitride particle mixes with matrix material and binding agent as abrasive grain.To obtain the mixture extrusion forming and at about 1000 ℃ of sintering to form grinding stone.Compare with traditional grinding stone, the nonferromagnetic substance of thus obtained grinding stone has greatly improved.
Various details embodiment.Yet the present invention is not limited to these embodiment.
Embodiment 1-10:
Be 10 μ m in 100 mass parts median sizes, contain in the hexagonal boron nitride of other impurity of 0.8% oxygen impurities and 0.2%, add catalyst substance 10 mass parts shown in the various table 1 composed as follows.In the table 1, (1): (2) refer to that basic metal, alkaline-earth metal and nitride thereof and nitrogen boride (are different from LiMBN 2) total molfraction and 1 molar part LiMBN 2Ratio.Mixture is at 1.5t/cm 2Pressure under be suppressed into diameter and be 26mm, highly be the briquetting of 32mm, each briquetting is placed in as shown in Figure 1 the reactor.
Table 1
Catalyst substance (1) Catalyst substance (2) (1) oxygen level (2) oxygen level (1)∶(2) Transformation efficiency (%) Toughness values (%) Shape anisotropy
Embodiment 1 LiCaBN 2 Li 0.37 0.12 1∶5 51 64 1.85
Embodiment 2 LiCaBN 2 Li 3N 0.37 0.26 1∶5 59 62 1.81
Embodiment 3 LiCaBN 2 Li 3BN 2 0.37 0.24 1∶7 56 64 1.80
Embodiment 4 LiCaBN 2 Ca 3B 2N 4 0.37 0.21 1∶7 52 67 1.84
Embodiment 5 LiCaBN 2 Li 3BN 2-Ca 3B 2N 4 0.37 0.24-0.21 1∶2∶5 51 63 1.84
Embodiment 6 LiCaBN 2 Mg 0.37 0.18 1∶5 58 63 1.82
Embodiment 7 LiBaBN 2 Li 3BN 2 0.38 0.24 1∶7 42 59 1.86
Embodiment 8 LiBaBN 2 Ca 3B 2N 4 0.38 0.21 1∶7 47 57 1.88
Embodiment 9 LiCaBN 2 K 3N 0.37 0.26 1∶5 50 67 1.81
Embodiment 10 LiCaBN 2 Mg 3N 2 0.37 0.22 1∶5 55 64 1.83
Comparative Examples 1 LiCaBN 2 -- 0.37 -- 1∶0 32 49 1.91
Comparative Examples 2 Li 3BN 2 -- 0.24 -- 1∶0 22 35 1.75
Comparative Examples 3 Ca 3B 2N 4 -- 0.21 -- 1∶0 23 38 1.74
Comparative Examples 4 Mg -- 0.18 -- 1∶0 29 30 1.70
Comparative Examples 5 LiCaBN 2 Li 8SiN 4 0.37 0.17 1∶0.04 32 55 1.88
Comparative Examples 6 LiCaBN 2 Ca 5Si 2N 6 0.37 0.15 1∶0.03 32 54 1.89
In the reactor shown in Figure 1, have hollow, cylindrical outer wall 1 by the agalmatolite manufacturing as transmission medium, wherein placing the hollow circle tube well heater of making by graphite 2, this well heater contacts with the internal surface of outer wall, and is placing the agalmatolite member that is used as isolated component on the surface of well heater.The top of reactor and bottom are being assembled upper and lower energising steel loop 3 and top and bottom energising steel plate 4 respectively.Under top and bottom steel plate, alundum plate 5 is housed, two agalmatolite plates 6 as transmission medium are being housed under top steel plate and the top steel loop and on bottom steel plate and bottom steel loop.Agalmatolite plate 6 and agalmatolite member 8 define the accommodating chamber 7 of placing raw material.
Reactor is placed in the extremely-high tension generator, and 10 briquettings were handled 10 minutes under the pressure of 5Gpa, 1450 ℃ condition.
After processing finishes, from extremely-high tension generator, take out the synthetic blank, and the part of each blank is broken into is of a size of 5mm or littler particle.After in particle, adding sodium hydroxide and a spot of water, mixture heating up to about 320 ℃, is cooled off then.Clean refrigerative mixture and filtration with acid, to separate the purification cubic boron nitride.
In order to analyze, use another part grind into powder of mortar with described synthetic blank, and use X-ray diffractometer that the gained powder is carried out X-ray analysis, thereby determine the relative intensity of cubic boron nitride (111) diffracted ray (with respect to the CuK alpha-ray) and hexagonal boron nitride (002) diffracted ray (with respect to the CuK alpha-ray).By test, calculate the transformation efficiency that hexagonal boron nitride is converted into cubic boron nitride: { (owing to the intensity of cubic boron nitride)/(owing to the intensity of cubic boron nitride+) } * 100 (%) owing to the intensity of hexagonal boron nitride based on following formula.
Utilize toughness index that the physical strength of gained cubic boron nitride is estimated.Obtain toughness index by following mode.Particularly, the particle diameter of prepared cubic boron nitride is adjusted to the particle diameter grade 120/140 of JIS-B4130 regulation.Sample and a steel ball of predetermined amount are put into the container that volume is 2ml together.Use vibrator with this container of frequency vibration of 3000 ± 100/ minutes 30.0 ± 0.3 seconds, thereby the cubic boron nitride macrobead in the container is pulverized with steel ball.Sieve with 90 μ m sieves the powder that makes.Weighing sieve is gone up the weight of residue, and gained weight is represented to account for behind the grinding per-cent of the whole powder weight of gained.
Based on bulk specific gravity the shape anisotropy of gained cubic boron nitride is estimated.Specifically: use the true specific gravity (3.48g/cm of the bulk specific gravity of gained cubic boron nitride divided by cubic boron nitride 3) calculating shape anisotropy value.When calculated value hour, shape anisotropy height, otherwise when calculated value was big, shape anisotropy was low.
Transformation efficiency, toughness values and the shape anisotropy value of the synthetic blank of each embodiment gained are shown in previous table 1.
Comparative Examples 1-6
Every kind of catalyst substance forming shown in previous table 1 is joined in the hexagonal boron nitride.With the same condition of embodiment 1-10 under, use the reactor for treatment mixture same to make synthetic blank with implementing 1-10.Transformation efficiency, toughness values and the shape anisotropy value of synthetic blank are shown in previous table 1.
The crystal of the cubic boron nitride that makes in Comparative Examples is the shape of subglobular.In contrast, use the inventive method can make the shape anisotropy crystal of (promptly depart from circularity, be elongated or flat pattern) at an easy rate.Use abrasive tool that the anisotropic crystal of this shape height makes, parting tool etc. to show high the grinding or cutting property.In most of embodiment, transformation efficiency has surpassed 50%.Yet in Comparative Examples, transformation efficiency only reaches about 30%.
Embodiment 11 and Comparative Examples 7
To all carry out classification by the cubic boron nitride that embodiment 1 and Comparative Examples 1 method make according to the particle diameter grade of JIS-B4130 regulation.Using the particle diameter grade is that 100/120 abrasive material prepares polishing slate.Exactly be that the abrasive material of 50 volume %, the borosilicate glass gelling material that is used as binding agent of 18 volume % and the binding agent (resol) of 20 volume % are mixed.The gained mixture places atmosphere to burn till at 1000 ℃ the gained briquetting 150 ℃ of extrusion formings then.Used binding agent burns in the sintering process of producing polishing slate, thereby forms pore.The polishing slate that makes is thus combined with alloy matrix aluminum with the formation grinding stone, and grinding stone is ground test according to following condition.
Emery wheel: 1Al type, 180D * 5U * 3X * 76.2H
Shredder: transverse axis surface grinding machine (grinding wheel spindle motor: 3.7KW)
Workpiece: SKD-11 (HRc=62-64)
Workpiece surface is long-pending: 200mm * 100mm
Lapping mode: wet surperficial transverse grinding
Grinding condition:
Emery wheel circumferential speed: 1800m/min
Table speed: 15m/min
The crossbeam depth of cut: each 2mm
Depth of cut: 25 μ m
Polishing fluid:
JIS W2, cubic boron nitride special use (diluting 50 times)
Consumption: 9L/min
The evaluation result of the abrasive material that embodiment 1 and Comparative Examples 1 are made is shown in following table 2 with embodiment 11 and Comparative Examples 7 respectively.In following table 2, " grinding ratio " refers to the ratio of the volume that uses the workpiece that grinding stone grinds and the wear volume of grinding stone, and " grinding power " refers to the electric power that shredder consumes in process of lapping.In other words, grinding ratio is high more or grinding power is low more, and the nonferromagnetic substance of grinding stone is good more.
Table 2
Grinding ratio Grinding power (W)
Embodiment 11 1282 464
Comparative Examples 7 1215 507
Industrial usability
According to the present invention, hexagonal boron nitride can be converted into the cubic boron nitride with excellent mechanical strength, and hexagonal boron nitride to be converted into the conversion ratio of cubic boron nitride higher. The cubic boron nitride that makes thus has the shape anisotropy of height, can have for the production of multiple requirement the abrasive material of sharp cutting quality.

Claims (14)

1. a method of producing cubic boron nitride is included in catalyst substance and exists down, places cubic boron nitride to keep under the thermodynamically stable condition hexagonal boron nitride, thereby hexagonal boron nitride is converted into cubic boron nitride, and catalyst substance wherein contains LiMBN 2With at least a material that is selected from basic metal, alkaline-earth metal and nitride thereof and nitrogen boride, described LiMBN 2In M represent Ca, Sr, Ba, Ra, Be or Mg, wherein based on the LiMBN of 1 molar part 2, at least a amount of substance that is selected from basic metal, alkaline-earth metal and nitride thereof and nitrogen boride is the 0.3-20 molar part.
2. the method for claim 1, wherein said LiMBN 2Oxygen level be 1% or lower.
3. method as claimed in claim 1 or 2, the oxygen level of wherein said at least a material are 1% or lower.
4. the method for claim 1, wherein said LiMBN 2Be LiCaBN 2Or LiBaBN 2
5. the method for claim 1, wherein alkali-metal nitride comprises the nitride of Na, K, Rb, Cs and Fr.
6. the method for claim 1, wherein the nitride of alkaline-earth metal comprises the nitride of Ra, Be and Mg.
7. the method for claim 1, wherein the nitride of alkaline-earth metal is the nitride of Mg.
8. the method for claim 1, wherein alkali-metal nitrogen boride comprises Li 3BN 2
9. the method for claim 1, wherein the nitrogen boride of alkaline-earth metal comprises Ca 3B 2N 4And Mg 3B 2N 4
10. the method for claim 1, wherein the nitrogen boride of alkaline-earth metal is Ca 3B 2N 4
11. the method for claim 1, wherein catalyst substance contains LiCaBN 2And Li 3BN 2
12. the method for claim 1, the catalyst substance that wherein adds the 5-50 mass parts in the hexagonal boron nitride of 100 mass parts is to form mixture, and place cubic boron nitride to keep under the thermodynamically stable condition in this mixture, thereby hexagonal boron nitride is converted into cubic boron nitride.
13. by any cubic boron nitride that described method is produced among the claim 1-12.
14. grinding stone that uses the described cubic boron nitride of claim 13 to produce.
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US7214359B2 (en) 2003-02-03 2007-05-08 Showa Denko K.K. Cubic boron nitride, catalyst for synthesizing cubic boron nitride, and method for producing cubic boron nitride
CN100391586C (en) * 2005-03-25 2008-06-04 吉林大学 Method of synthesizing cubic boron nitride using alkali earth metal fluoride
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