Method for synthesizing coarse-grain degree cubic boron nitride

A technology of cubic boron nitride and synthesis method, which is applied in the direction of nitrogen compounds, chemical instruments and methods, boron compounds, etc., and can solve the problems of low grade, low extraction rate of coarse-grained cubic boron nitride, poor crystal shape, etc.

Inactive Publication Date: 2009-09-23
ZHENGZHOU ZHONGNAN JETE SUPERABRASIVES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the crystal size of cubic boron nitride produced in industry is below 500um, that is, finer than 40 mesh, the peak of particle size distribution is between 70 mesh and 140 mesh, and the extraction rate of coarse-grained cubic boron nitride is very low, the crystal shape is poor, and the grade Low

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] Will Li 3 BN 2 or Mg 3 B 2 N 4 or Ca 3 B 2 N 4 The content of catalyst powder and BN is 99%, B 2 o 3 The high-purity hexagonal boron nitride with a content of 0.4% is mixed and pressed into a cylindrical shape at a weight ratio of 1:7, put into a graphite heating tube, placed in a high-pressure chamber of a six-sided top press for synthesis, and pressurized to 45MPa. Heat to 1300°C, continue to pressurize, the first pause pressure is 75MPa, the pause time is 3 minutes, the second pause pressure is 85MPa, the pause time is 3 minutes, the synthetic pressure is 95MPa, the holding time is 15 minutes, then cool down and unload pressure.

[0015] Soak the compressed synthetic product in water, and then treat it with NaoH alkali to obtain amber cubic boron nitride crystals. The conversion rate of hexagonal boron nitride is 31%, 30 mesh to 60 mesh accounts for 62%, and the crystal form is complete.

Embodiment 2

[0017] Will Li 3 BN 2 or Mg 3 B 2 N 4 or Ca 3 B 2 N 4 Catalyst powder and BN content is 99.3%, B 2 o 3 High-purity hexagonal boron nitride with a content of 0.35% is mixed and pressed into a cylindrical shape at a weight ratio of 1:9, put into a graphite heating tube, placed in a high-pressure chamber of a six-sided top press for synthesis, and pressurized to 46MPa. Heat to 1350°C, continue to pressurize, the first pause pressure is 76MPa, pause time is 2.5 minutes, the second pause pressure is 84MPa, pause time is 2.5 minutes, the synthetic pressure is 98MPa, hold time is 14 minutes, then cool down and unload pressure.

[0018] Soak the compressed synthetic product in water, and treat it with NaoH alkali to obtain amber cubic boron nitride crystals. The conversion rate of hexagonal boron nitride is 33.5%, 30 mesh to 60 mesh accounts for 64.5%, and the crystal form is complete.

Embodiment 3

[0020] Will Li 3 BN 2 or Mg 3 B 2 N 4 or Ca 3 B 2 N 4 The content of catalyst powder and BN is 99.5%, B 2 o 3 The high-purity hexagonal boron nitride with a content of 0.3% is mixed and pressed into a cylindrical shape at a weight ratio of 1:10, put into a graphite heating tube, placed in a high-pressure chamber of a six-sided top press for synthesis, and pressurized to 47MPa. Heat to 1400°C, continue to pressurize, the first pause pressure is 77MPa, pause time is 2 minutes, the second pause pressure is 83MPa, pause time is 2 minutes, the synthetic pressure is 99MPa, hold time is 13 minutes, then cool down and unload pressure.

[0021] Soak the compressed synthetic product in water, and then treat it with KoH alkali to obtain amber cubic boron nitride crystals. The conversion rate of hexagonal boron nitride is 35%, 30 mesh to 60 mesh accounts for 65%, the crystal form is complete, and the transparency is good.

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Abstract

The invention belongs to the technical field of superhard material synthesis, in particular to a synthesis method for producing coarse-grained cubic boron nitride. Its main features are: select refined high-purity hexagonal boron nitride with BN content ≥ 99% and B2O3 content ≤ 0.4% as raw material, mix it with Li3BN2 or Mg3B2N4 or Ca3B2N4 catalyst powder evenly, and synthesize coarse-grained cubic boron nitride crystals. The crystal size reaches 30 mesh, and the proportion of 30 mesh to 60 mesh is 60~70%, and the coarse cubic boron nitride crystal is transparent, the crystal form is relatively complete, and the conversion rate of hexagonal boron nitride is 30~40%, which has industrial production value.

Description

technical field [0001] The invention belongs to the technical field of superhard material synthesis, in particular to a synthesis method for producing coarse-grained cubic boron nitride. Background technique [0002] Cubic boron nitride is an artificial crystal material that does not exist in nature. It has high hardness, excellent thermal stability and chemical stability second only to diamond. It can be widely used as super abrasives, grinding tools and tool materials in the fields of grinding and cutting of various steels, cast iron and other ferrous materials and their alloys. [0003] In the prior art, the method for industrially producing and synthesizing cubic boron nitride mainly uses hexagonal boron nitride as a raw material, and alkali metals Li, Mg, Ca, etc., and boron nitride as catalyst materials are synthesized under high temperature and high pressure. At present, the crystal size of cubic boron nitride produced in industry is below 500um, that is, finer than ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B21/064C01B35/14
Inventor 张相法张奎
Owner ZHENGZHOU ZHONGNAN JETE SUPERABRASIVES
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