Method for preparing pyrolytic boron nitride material

A boron nitride and pyrolysis technology is applied in the field of preparation of pyrolysis boron nitride materials, which can solve the problems of difficult process control, high requirements on production equipment, personnel, environmental hazards and process stability, and achieves the improvement of ceramic output. efficiency and production efficiency, improving process controllability and stability, simplifying process parameters and the effect of experimental equipment

Inactive Publication Date: 2017-10-20
NAT UNIV OF DEFENSE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

BCl is currently widely used 3 and NH 3 PBN is prepared from a two-component raw material system, but this method has problems such as high deposition temperature (above 1900 ° C), large energy consumption, low deposition rate, and low ceramic yield. At the same time, BCl 3 and NH 3 The flow rate and ratio of the flow rate need to be strictly controlled, the process stability is high, the process control is difficult, the production cost is high, and a large amount of NH will be generated during the production process. 4 Cl powder by-products and highly corrosive HCl tail gas are serious hazards to production equipment, personnel, and the environment, which limits the improvement of the quality of PBN materials and the increase in output
In addition, the layered crystallinity of pyrolytic boron nitride is very sensitive to changes in process parameters such as temperature, pressure, gas flow, and raw material gas concentration, and the deposition process of pyrolytic boron nitride materials generally lasts for tens of hours. Small fluctuations in the final pyrolytic boron nitride material often lead to cracking, delamination and other defects
Therefore, due to the harsh preparation process conditions of pyrolytic boron nitride, high preparation cost and unstable product performance, the practical application of pyrolytic boron nitride is far from meeting people's expectations.

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  • Method for preparing pyrolytic boron nitride material
  • Method for preparing pyrolytic boron nitride material

Examples

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Effect test

Embodiment 1

[0032] A preparation method of pyrolytic boron nitride material of the present invention, comprising the following steps:

[0033] (1) Preparation of the deposition base mold: Use a high-purity graphite disc with a diameter of 100 mm and a thickness of 5 mm as the base mold material. After the deposition surface is polished, it is cleaned ultrasonically in absolute ethanol to remove graphite dust and impurities on the deposition surface. After drying, it is installed and fixed on the rotary stage in the chemical vapor deposition furnace, so that the surface to be deposited faces the direction of the source of the deposition gas; wherein, the material of the high-purity graphite disc is hot isostatic graphite with a density of 1.83g / cm 3 , porosity 10%, thermal expansion coefficient 4.2×10 -6 K -1 .

[0034] (2) Vacuumize to 1 Pa in the chemical vapor deposition furnace, raise the temperature to 1150°C at a rate of 15°C / min, keep it for 60 minutes, and then continue to hea...

Embodiment 2

[0042] A preparation method of pyrolytic boron nitride material of the present invention, comprising the following steps:

[0043] (1) Preparation of the deposition base mold: Use a high-purity graphite disc with a diameter of 100 mm and a thickness of 5 mm as the base mold material. After the deposition surface is polished, it is cleaned ultrasonically in absolute ethanol to remove graphite dust and impurities on the deposition surface. After drying, it is installed and fixed on the rotary stage in the chemical vapor deposition furnace, so that the surface to be deposited faces the direction of the source of the deposition gas; wherein, the material of the high-purity graphite disc is hot isostatic graphite with a density of 1.83g / cm 3 , porosity 10%, thermal expansion coefficient 4.2×10 -6 K -1 .

[0044] (2) Vacuumize to 1 Pa in the chemical vapor deposition furnace, raise the temperature to 1150°C at a rate of 10°C / min, keep it for 30 minutes, and then continue to hea...

Embodiment 3

[0049] A preparation method of pyrolytic boron nitride material of the present invention, comprising the following steps:

[0050] (1) Preparation of the deposition base mold: Use a high-purity graphite square sheet with a length × width of 150 × 50 mm and a thickness of 5 mm as the base mold material. After the deposition surface is polished and polished, it is ultrasonically cleaned in absolute ethanol to remove the deposition surface. Graphite dust and impurities, after drying, are installed and fixed on the rotary stage in the chemical vapor deposition furnace, so that the surface to be deposited faces the direction of the source of the deposition gas; the material of the high-purity graphite disc is hot isostatic pressing Graphite, density 1.83g / cm 3 , porosity 10%, thermal expansion coefficient 4.2×10 -6 K -1 .

[0051] (2) Vacuumize to 1 Pa in the chemical vapor deposition furnace, raise the temperature to 1150°C at a rate of 12°C / min, keep it for 60 minutes, and th...

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Abstract

The invention discloses a method for preparing a pyrolytic boron nitride material. The method comprises the following steps: putting a substrate mold in an air-carrying atmosphere carrying borazine vapor under a vacuum condition, and pyrolyzing borazine which constantly deposits on the depositing surface of the substrate mold by adopting a chemical vapor deposition method to form the pyrolytic boron nitride material. The preparation method of the pyrolytic boron nitride material has the advantages of simple and easily controlled process, low cost, low energy consumption, high yield, environmental friendliness and the like.

Description

technical field [0001] The invention belongs to the technical field of pyrolysis material preparation, and in particular relates to a preparation method of pyrolysis boron nitride material. Background technique [0002] Pyrolytic boron nitride (PBN) material refers to the millimeter-scale boron nitride material obtained by chemical vapor deposition on the surface of graphite substrate through long-term rapid growth. Pyrolytic boron nitride material has high purity, corrosion resistance, high temperature resistance, thermal shock resistance, high thermal conductivity, low dielectric constant, high dielectric strength, low high temperature outgassing, and non-wetting with most molten semiconductors and metals And many other excellent properties, are widely used as crucibles and boats for compound semiconductor single crystal growth and special metal smelting, traveling wave tube energy transmission windows and clamping rods, PBN / PG (pyrolytic boron nitride / pyrolytic graphite) ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B21/064
CPCC01B21/0646C01P2002/72C01P2004/03C01P2006/10C01P2006/32C01P2006/80
Inventor 高世涛李斌张长瑞李端杨雅萍刘荣军
Owner NAT UNIV OF DEFENSE TECH
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