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Cubic boron nitride-nano polycrystalline diamond composite material and preparation method thereof

A technology of cubic boron nitride and polycrystalline diamond, applied in nitrogen compounds, chemical instruments and methods, nano-carbon, etc., can solve problems such as low performance of polycrystalline diamond, high preparation conditions, and incomplete transformation of carbon nano-onions

Pending Publication Date: 2020-06-30
YANSHAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the closed and continuous carbon shell restricts the sliding of the (002) plane, which leads to the generation of stress, and the formation of twin diamonds is the result of cumulative stress release [Tang Hu. Synthesis of nano-polycrystalline diamond and carbon nano-onion high temperature Research on the mechanism of high-pressure phase transition [D]. Qinhuangdao: Yanshan University, 2018]
[0004] Most of the polycrystalline diamonds prepared by the prior art have low performance, and the preparation conditions of polycrystalline diamond with high performance are relatively high, and there is the problem of incomplete conversion of carbon nano-onions

Method used

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preparation example Construction

[0036] The invention also discloses a preparation method of cubic boron nitride-nanometer polycrystalline diamond composite material, comprising the following steps:

[0037] S1, vacuum annealing treatment to prepare carbon nano-onions;

[0038] The raw material used is nano-diamond prepared by the detonation method, and its average grain size is about 5nm. Vacuum annealing is carried out on the nano-diamond. Carbon nano-onions with a particle size of about 5nm;

[0039] S2. Cubic boron nitride is mixed with the carbon nano-onions prepared in step S1 at 15-50 wt.% of the total amount to prepare a mixture;

[0040] The mixture is pre-pressed, the pressure is 400-600MPa, and the pressure-holding time is 30-60s, and the predicted sample is obtained;

[0041] Then, put the pre-pressed sample into the mold for sintering at high temperature and high pressure to prepare cubic boron nitride-nanometer polycrystalline diamond composite material.

[0042] Further, in the step S2, the ...

Embodiment 1

[0048] A preparation method of cubic boron nitride-nanometer polycrystalline diamond composite material, comprising the following steps:

[0049] S1. Annealing the detonation nano-diamond powder (average grain size 5nm) with a vacuum degree of 1Pa, annealing temperature of 900°C, and no heat preservation, to obtain an OLC containing a diamond crystal core.

[0050] S2. Mix 1.5mg of cBN powder and 8.5mg of OLC powder in a mortar evenly, then pre-press the powder mixture, the pre-press pressure is 400MPa, pre-press for 30s, and then, the pre-pressed sample is subjected to high temperature High pressure sintering. First, the sample was slowly pressured to 8GPa within 10 hours; then, the temperature was raised from room temperature to 1600°C at a rate of 10°C / min, and kept for 5 minutes. The program controls the cooling, slowly releases the pressure, and makes the blank. The prepared blank is subjected to surface grinding and deburring treatment to obtain cubic boron nitride-nan...

Embodiment 2

[0053] A preparation method of cubic boron nitride-nanometer polycrystalline diamond composite material, comprising the following steps:

[0054] S1. Annealing the detonation nano-diamond powder (average grain size 5nm) with a vacuum degree of 1 Pa and an annealing temperature of 950° C. without heat preservation to obtain an OLC containing a diamond crystal core.

[0055] S2. Mix 3 mg of cBN powder and 7 mg of OLC powder in a mortar evenly, then pre-press the powder mixture with a pre-pressing pressure of 500 MPa for 40 seconds, and then sinter the pre-pressed sample at high temperature and high pressure . First, the sample was slowly pressured to 10GPa within 11 hours; then, the temperature was raised from room temperature to 2200°C at a rate of 10°C / min and kept for 60 minutes. The program controls the cooling, slowly releases the pressure, and makes the blank. The prepared blank is subjected to surface grinding and deburring treatment to obtain cubic boron nitride-nanome...

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Abstract

The invention belongs to the technical field of composite materials, and relates to a cubic boron nitride-nano polycrystalline diamond composite material and a preparation method thereof. The cubic boron nitride-nano polycrystalline diamond composite material comprises onion-like carbon (OLC) and cubic boron nitride (cBN) and particularly comprises the raw mateirals by mass: 15-50 wt.% of cBN andthe balance being OLC. The preparation method comprises the steps: mixing the two raw materials OLC and cBN according to different mass ratios; and pre-pressing the mixture of the cBN and the OLC which are mixed; and then carrying out high-temperature and high-pressure sintering on the pre-pressed sample, wherein the sintering pressure is 8-25 GPa, the sintering temperature is 1600-2200 DEG C, andthe heat preservation time is 5-60 min; then cooling and releasing the pressure, and thus preparing the cubic boron nitride-nano polycrystalline diamond composite material. By utilizing the similarity and correspondence of the cBN and the diamond structure, the sintering condition is reduced, the problem of high sintering condition for preparing the polycrystalline diamond sintered body by adopting the OLC as the raw material is solved, and the high-hardness cubic boron nitride-nano polycrystalline diamond composite material is obtained.

Description

technical field [0001] The invention belongs to the technical field of composite materials, and relates to a cubic boron nitride-nanometer polycrystalline diamond composite material and a preparation method thereof. Background technique [0002] Polycrystalline diamond (PCD) has high hardness and wear resistance, it overcomes the shortcomings of single crystal diamond anisotropy and {111} crystal plane dissociation damage, and is widely used in aerospace, electronics, construction, gemstones Processing, oil drilling and geological exploration and many other fields. The hardness of polycrystalline cubic boron nitride (PCBN) is second only to diamond. The polycrystalline grains are arranged in disorder, isotropic, and there is no cleavage plane. It has high hardness, wear resistance and impact resistance. Good thermal stability, chemical stability and thermal conductivity, low friction coefficient, widely used in industrial cutting, new tool materials, wear-resistant cast iro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B21/064C01B32/15C01B32/18C04B35/52C04B35/5831C04B35/622B82Y30/00B82Y40/00
CPCC01B21/0648C01B32/15C01B32/18C04B35/52C04B35/5831C04B35/622B82Y30/00B82Y40/00
Inventor 李艳国邹芹王明智赵玉成王志伟邹娟尹育航
Owner YANSHAN UNIV