Preparation method for cubic boron nitride

A technology of cubic boron nitride and borax, which is applied in the field of preparing cubic boron nitride, can solve the problems of low conversion rate of cubic boron nitride, achieve the effects of shortening processing cost and time, low crystallinity, and easy conversion into

Inactive Publication Date: 2019-09-20
大连新翔工业材料有限公司
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Problems solved by technology

[0003] However, the existing high-temperature and high-pressure synthesis of cubic boron nitride is to directly convert hexagonal boron nitride into cubic boron nitride, which requires higher temperature and pressure to achieve, and the conversion rate of the existing synthetic cubic boron nitride is relatively low. Low

Method used

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Embodiment Construction

[0016] Embodiments of the present invention will be further described in detail below. The following examples are used to illustrate the present invention, but should not be used to limit the scope of the present invention.

[0017] The method of the present invention comprises the following steps:

[0018] S1, purifying industrial-grade borax and urea by recrystallization to achieve analytical purity;

[0019] S2, heat-preserve borax at 400°C for 0.5h for dehydration treatment, and dry the dehydrated borax and urea;

[0020] S3, boric acid and urea are weighed according to the mass ratio of 1:1, and borax is added as a cosolvent, and the borax accounts for 1 to 10% of the total mass of boric acid and urea; then put into a ball mill and fully mix;

[0021] S4, put the mixed material into a crucible, put it into a high-temperature furnace, raise the temperature to 950° C. for 1 hour in a nitrogen atmosphere, and then raise the temperature to 1500° C. for a second heat treatme...

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Abstract

The invention discloses a preparation method for cubic boron nitride. The preparation method for cubic boron nitride comprises the following steps: purifying industrial grade borax and urea through recrystallization to obtain analytically-pure industrial grade borax and urea; dehydrating and drying the borax; adding borax as a cosolvent; putting the above substances into a ball mill for uniform mixing; feeding the formed mixture into a crucible, and putting the crucible in a high temperature furnace to prepare boron nitride powder; grinding the boron nitride powder and performing washing and purification to obtain hexagonal boron nitride powder; and drying the hexagonal boron nitride powder and performing pressing to form a green body; pressing the green body at a temperature of 1300 DEG C and a pressure of 4 GPa for 20 min to obtain a pre-pressed synthetic rod; crushing the pre-pressed synthetic rod and then performing screening to obtain a sieved material, and carrying out annealing for 50 min to obtain pretreated hexagonal boron nitride powder; mixing the pretreated hexagonal boron nitride powder and a metal nitride catalyst to prepare a mixture, and pressing the mixture at a temperature of 30 DEG C and a pressure of 25 GPa to form a mixture synthetic rod; and carrying out high-temperature and high-pressure sintering at a temperature of 1300-1600 DEG C and a pressure of 4-7 GPa to prepare a cubic boron nitride crystal. The preparation method of the invention has the advantages of rapid conversion, low cost, high utilization rate of raw materials, etc.

Description

technical field [0001] The invention relates to the field of boron nitride production and processing, in particular to a method for preparing cubic boron nitride using hexagonal boron nitride as a raw material. Background technique [0002] Cubic boron nitride is a superhard material second only to diamond in hardness. It not only has many excellent properties of diamond, but also has higher thermal stability and chemical inertness to iron group metals and their alloys, making up for the inability of diamond to cut iron group metals. [0003] However, the existing high-temperature and high-pressure synthesis of cubic boron nitride is to directly convert hexagonal boron nitride into cubic boron nitride, which requires higher temperature and pressure to realize, and the conversion rate of the existing synthetic cubic boron nitride is relatively low. Low. Contents of the invention [0004] The purpose of the present invention is to provide a method for preparing cubic boron...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B21/064C04B35/5831C04B35/622
CPCC01B21/064C04B35/5831C04B35/622
Inventor 孙晓鹏刁玉萍马振涛
Owner 大连新翔工业材料有限公司
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