A method for preparing dense polycrystalline diamond and a boron-doped polycrystalline diamond

A technology of polycrystalline diamond and boron doping, which is applied in the field of boron-doped polycrystalline diamond, can solve the problems of high price and unacceptable market, and achieve the effects of improving performance, reducing synthesis pressure and increasing size

Active Publication Date: 2021-06-29
YANSHAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Unfortunately, harsh synthesis conditions (≥15GPa and 2300°C) limit the industrial production of nano-polycrystalline diamond, and a small amount of production is also difficult to accept in the market due to the high cost of the price.

Method used

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  • A method for preparing dense polycrystalline diamond and a boron-doped polycrystalline diamond
  • A method for preparing dense polycrystalline diamond and a boron-doped polycrystalline diamond
  • A method for preparing dense polycrystalline diamond and a boron-doped polycrystalline diamond

Examples

Experimental program
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Effect test

Embodiment 1

[0039] (1) Firstly, carbon nano-onions with diamond cores (particle size: 2-20nm) prepared from industrial detonation nano-diamonds by vacuum annealing (vacuum degree 1Pa, annealing temperature 1300°C, no heat preservation), mixed with mass The percentage is 3% (accounting for the sum of carbon nano-onions and elemental boron mass) elemental boron, which is uniformly mixed by ball milling under an inert environment;

[0040] (2) Utilize the hydraulic press to preliminarily pre-press the uniform mixture, with a pressure of 500 MPa and room temperature;

[0041] (3) The preliminary pre-pressed sample prepared in step (2) was pre-pressed twice under high pressure using a domestic six-sided top press, the molding pressure was 5GPa, and the temperature was 800°C to obtain a preform;

[0042] (4) Use the domestic six-sided roof to install the 6-8 multi-stage supercharging device to generate the preformed material obtained by high temperature and high pressure (8GPa and 1800°C); the ...

Embodiment 2

[0052] (1) First, the carbon nano-onions (the annealing conditions are the same as in Example 1, and the particle size is 2 to 20nm) prepared by industrial detonation nano-diamonds through vacuum annealing, the doping mass percentage is 1% ( Accounting for the sum of the mass of carbon nano-onions and elemental boron), the elemental boron is uniformly mixed by means of ball milling under an inert environment;

[0053] (2) Utilize the hydraulic press to preliminarily pre-press the uniform mixture, with a pressure of 500 MPa and room temperature;

[0054] (3) The preliminary pre-pressed sample prepared in step (2) was pre-pressed twice under high pressure using a domestic six-sided top press, and the molding pressure was 5GPa, and the temperature was 600°C to obtain a preform;

[0055] (4) Use the domestic six-sided roof to install the 6-8 multi-stage supercharging device to generate the preformed material obtained by high temperature and high pressure (10GPa and 2000°C); the hi...

Embodiment 3

[0063] (1) Firstly, the carbon nano-onions (the annealing conditions are the same as in Example 1, and the particle size is 2 to 20nm) prepared by industrial detonation nano-diamonds through vacuum annealing, the doping mass percentage is 10% ( Accounting for the sum of the mass of carbon nano-onions and elemental boron) elemental boron is uniformly mixed by means of ball milling under an inert environment;

[0064] (2) Utilize the hydraulic press to preliminarily pre-press the uniform mixture, with a pressure of 500 MPa and room temperature;

[0065] (3) The preliminary pre-pressed sample prepared in step (2) was pre-pressed twice under high pressure by using a domestic six-sided top press, with a molding pressure of 3GPa and a temperature of 600°C to obtain a preform;

[0066] (4) Preforms obtained by direct high-temperature and high-pressure treatment (5GPa and 1200°C) using domestic six-sided roof; Raise the temperature to 1200°C at a heating rate of 1,200°C, hold the tem...

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Abstract

The invention provides a method for preparing dense polycrystalline diamond and a boron-doped polycrystalline diamond, which relate to the technical field of high-performance materials. The present invention mixes carbon nano-onions with diamond cores and a boron source to obtain a mixture; the boron source is elemental boron or boron oxide; then the mixture is sequentially subjected to preliminary pre-press molding and secondary high-pressure pre-press molding , to obtain a preform; then carry out high-temperature and high-pressure sintering of the preform to obtain a dense boron-doped polycrystalline diamond block; the conditions for the high-temperature and high-pressure sintering include: the sintering temperature is 1200-2000 ° C, and the sintering pressure is 5 ~10GPa, heat preservation and pressure holding time is 1~200min. The invention uses carbon nano-onions with diamond cores as carbon raw materials and adds boron element, can greatly reduce the synthesis conditions of polycrystalline diamond, is suitable for industrial production, and improves the performance of polycrystalline diamond.

Description

technical field [0001] The invention relates to the technical field of high-performance materials, in particular to a method for preparing dense polycrystalline diamond and a boron-doped polycrystalline diamond. Background technique [0002] Diamond is the hardest material known in the world. Since the artificial synthesis of diamond in the 1950s, diamond and its products have been widely used in the field of processing, such as cutting and grinding tools. However, synthetic diamond cannot be directly used as a cutting tool due to its fine particles, and isotropic polycrystalline diamond is usually obtained by sintering diamond micropowder through powder sintering. However, based on thermodynamic considerations, diamond is a metastable phase at atmospheric pressure, and a certain high temperature will promote its transformation into graphite. At the same time, diamond has a very high decomposition temperature, which means that it is not feasible to obtain polycrystalline d...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/52C04B35/622C04B35/645
CPCC04B35/52C04B35/622C04B35/645C04B2235/421C04B2235/6562C04B2235/6567C04B2235/6581C04B2235/662C04B2235/96
Inventor 王明智唐虎袁小红
Owner YANSHAN UNIV
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