Preparation method of pure or composite hexagonal boron nitride densified macroscopic body

A technology of hexagonal boron nitride and macroscopic bodies, which is applied in the field of preparation of hexagonal boron nitride compacted macroscopic bodies, can solve the problem of high forming temperature of hexagonal boron nitride compacted macroscopic bodies, increase the contact area between layers and improve the strength , reduce the effect of high temperature

Active Publication Date: 2022-01-14
SHENZHEN GRADUATE SCHOOL TSINGHUA UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] In order to solve the problem that the forming temperature of hexagonal boron nitride compacted macroscopic body is too high, the present invention proposes a preparation method of pure or composite hexagonal boron nitride compacted macroscopic body

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  • Preparation method of pure or composite hexagonal boron nitride densified macroscopic body
  • Preparation method of pure or composite hexagonal boron nitride densified macroscopic body
  • Preparation method of pure or composite hexagonal boron nitride densified macroscopic body

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no. 1 Embodiment approach

[0043] The first specific embodiment of the present invention provides a kind of preparation method of pure hexagonal boron nitride compacted macroscopic body, it comprises the following steps:

[0044] (1) obtaining raw materials, the raw materials are hexagonal boron nitride nanosheet powder, and the solvent content in the raw materials is 0-10wt%;

[0045](2) Hot pressing the raw material in step (1) at a temperature of 25-500° C. to obtain the hexagonal boron nitride densified macroscopic body.

[0046] The second specific embodiment of the present invention provides a method for preparing a composite hexagonal boron nitride compacted macroscopic body, comprising the following steps:

[0047] (1) Obtain raw materials, the raw materials contain hexagonal boron nitride nanosheet powder and additives, the solvent content in the raw materials is 0-10wt%, and the mass percentage of the additives in the raw materials is less than 50%;

[0048] (2) Hot pressing the raw material ...

Embodiment 1

[0062] (1) Take 2 g of urea-assisted mechanical exfoliation of commercial hexagonal boron nitride (Momentive, PT110) hexagonal boron nitride nanosheets (purity 99.5wt%, average diameter 200nm, average thickness 1nm) dissolved in 1L deionized water, ultrasonic After uniform dispersion, filter with nylon membrane (pore size 0.2μm), and add the filtered powder to 200ml deionized water again, sieve the nanosheets by centrifugation at 500rpm and 3000rpm respectively, and finally pass the supernatant through a lyophilizer Drying (-50°C, 0.1bar, 12h) to obtain hexagonal boron nitride nanosheet powder, its water content is about 5wt%, and it is marked as BNNS-0.5 (representing the nanosheet obtained by sieving at 500 rpm) and BNNS-3 (represents nanosheets obtained by sieving at 500 rpm).

[0063] (2) Take 1.2g of the hexagonal boron nitride nanosheet powder BNNS-3 prepared above and put it into a cylindrical mold steel mold with a diameter of 13mm. The hot pressing conditions are: 25°...

Embodiment 2

[0068] (1) Get the hexagonal boron nitride nanosheets (purity 99wt%, sheet diameter 0.2 ~ 1 μm, sheet thickness 2 ~ 50nm) obtained by ultrasonic peeling of 2g isopropanol, and mix it evenly with polyvinyl alcohol (PVA) aqueous solution, by mass percentage Calculated, the hexagonal boron nitride is 50wt%, and the polyvinyl alcohol content is 50wt%. After the mixed slurry is rapidly cooled to solid, freeze-dried to obtain hexagonal boron nitride-polyvinyl alcohol composite powder, the water content of which is 5 wt%.

[0069] (2) Prepare the composite powder obtained above by hot-pressing under the hot-pressing equipment in step (2) of Example 1 to obtain the hexagonal boron nitride-polyvinyl alcohol composite macroscopic body, and the specific hot-pressing parameters are 90°C, Hot pressing at 375MPa for 1h.

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Abstract

The invention discloses a preparation method of a pure or composite hexagonal boron nitride densified macroscopic body. The preparation method of the pure hexagonal boron nitride densified macroscopic body comprises the following steps of: (1) obtaining a raw material which is hexagonal boron nitride nanosheet powder with a solvent content of 0-10 wt%; and (2) carrying out hot press molding on the raw material in the step (1) at the temperature of 25-500 DEG C to obtain the hexagonal boron nitride densified macroscopic body. The forming temperature of the hexagonal boron nitride macroscopic body can be greatly reduced, and the prepared hexagonal boron nitride densified macroscopic body has the characteristics of high density, high strength, high thermal stability and high chemical stability.

Description

technical field [0001] The invention relates to the field of forming densified ceramics, in particular to a method for preparing a pure or composite hexagonal boron nitride densified macroscopic body. Background technique [0002] Hexagonal boron nitride (h-BN) has unique properties, such as excellent physical and chemical stability, good friction and wear properties, high thermal conductivity and dielectric properties, etc. Therefore, bulk hexagonal boron nitride is widely used in high-temperature structural materials, thermal conductivity, dielectric materials and other fields. [0003] Nowadays, the compacted bulk hexagonal boron nitride is mainly obtained by mixing high-purity boron nitride powder and a small amount of sintering agent powder, and then sintering at high temperature (high pressure). According to the sintering process, the powder sintering method can be classified into: pressureless sintering, high pressure sintering and spark plasma sintering. Pressurele...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B30/00C04B26/04C04B26/20C04B35/5833C04B35/645
CPCC04B30/00C04B26/20C04B26/04C04B35/583C04B35/645C04B2111/00008C04B2235/3409C04B2235/3217C04B2235/3865C04B2235/3856C04B2235/425C04B2201/20C04B2201/50C04B2235/77C04B2235/96C04B14/327C04B24/2623C04B14/30C04B14/303C04B14/326C04B14/325C04B14/024
Inventor 朱九一苏阳成会明
Owner SHENZHEN GRADUATE SCHOOL TSINGHUA UNIV
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