CN112159158A

CN112159158A - Manufacturing process of boron nitride block and boron nitride block

Info

Publication number: CN112159158A
Application number: CN202010922421.5A
Authority: CN
Inventors: 陈敦汉; 张卫; 彭浩
Original assignee: Zhejiang Chant New Materials Technology Co ltd
Current assignee: Zhejiang Chant New Materials Technology Co ltd
Priority date: 2020-09-01
Filing date: 2020-09-04
Publication date: 2021-01-01

Abstract

The invention provides a boron nitride block and a manufacturing process thereof, wherein the manufacturing process comprises the following steps of (A) dry mixing: dry blending boron nitride powder with boric acid powder and/or boron oxide powder; (II) prepressing: prepressing the powder mixed in the step (I) to form a boron nitride block; (III) crushing: crushing and granulating the prepressed boron nitride blocks, and screening the granulated particles; (IV) forming: and (3) carrying out dry pressing on the particles in the step (III). According to the manufacturing process of the boron nitride block and the boron nitride block, the density of the dry-pressed boron nitride block is high, the process is simple, the dry-pressing forming is directly performed, high-temperature and high-pressure sintering is not needed, machining forming is not needed, and the cost is low. Boric acid serves as a bridge between boron nitride particles, and boron nitride exhibits high temperature resistance and insulation properties as a bulk host material.

Description

Manufacturing process of boron nitride block and boron nitride block

Technical Field

The invention relates to the technical field of material preparation, in particular to a boron nitride block and a manufacturing process thereof.

Background

The boron nitride blocks in the prior art typically require high temperature and high pressure sintering and also machining. As shown in fig. 1, a conventional process flow of high density BN (boron nitride) material in the prior art is provided, which comprises: firstly, mixing BN and boron oxide in a ball mill by ball milling; secondly, drying by using a dryer; thirdly, pressing the blank by a press; (IV) sintering through a special high-temperature high-pressure sintering furnace for BN; and (V) machining and forming through machining equipment after sintering is finished. The boron nitride block processing technology in the prior art is complex in process and high in cost.

Disclosure of Invention

The invention aims to provide a boron nitride block and a manufacturing process thereof.

In order to solve the above technical problems, the present invention provides a process for manufacturing a boron nitride block, the process comprising the steps of,

firstly, mixing: mixing boron nitride powder with boric acid powder and/or boron oxide powder;

(II) prepressing: prepressing the powder mixed in the step (I) to form blocky boron nitride;

(III) crushing: crushing and granulating the pre-pressed massive boron nitride;

(IV) forming: and pressing and molding the boron nitride particles.

Preferably, step (three) further comprises sieving the granulated particles.

Preferably, the step (two) and the step (three) are sequentially repeated 1 or more times before the step (four).

Preferably, in step (one), the boron nitride powder and the boric acid powder and/or the boron oxide powder are mixed under dry conditions.

Preferably, in step (three), the particle size of the sieved particles is between 50 and 300 microns.

Preferably, in the step (one), the boron nitride is 88-98% by mass.

Preferably, in step (one), the boron nitride has a hexagonal crystal structure.

Preferably, in step (one), the hexagonal boron nitride crystals have a particle size in the range of 0.1 micron to 50 microns.

The application also provides a dry-pressed boron nitride block, which is manufactured by adopting the manufacturing process of any one of claims 1 to 6.

According to the manufacturing process of the boron nitride block and the boron nitride block, the density of the dry-pressed boron nitride block is high, the process is simple, the dry-pressing forming is directly performed, high-temperature and high-pressure sintering is not needed, machining forming is not needed, and the cost is low. Boric acid serves as a bridge between boron nitride particles, and boron nitride exhibits high temperature resistance and insulation properties as a bulk host material.

Drawings

FIG. 1 is a process flow diagram of a prior art BN material;

FIG. 2 is a flow chart of a process for manufacturing a boron nitride block of the present application;

FIG. 3 is a graph of the effect of pre-compaction crushing times on finished BN sheet density of the present application;

FIG. 4 is a graph of the effect of pre-stress on density of BN sheet of the present application;

FIG. 5 is a graph of the effect of forming pressure on BN sheet density of the present application;

Detailed Description

The present invention is further described below in conjunction with the following figures and specific examples so that those skilled in the art may better understand the present invention and practice it, but the examples are not intended to limit the present invention.

As shown in fig. 2, the present invention provides a process for manufacturing a boron nitride block, the process comprising the steps of,

dry mixing: dry-mixing boron nitride powder and boric acid powder and/or boron oxide powder, wherein the boron nitride and/or boric acid has a mass ratio of 88-98%, the boron nitride has a hexagonal crystal structure, and the particle size of the sieved particles is 50-300 microns.

(II) prepressing: pre-pressing the powder mixed in the step one to form blocky boron nitride (BN column);

(III) crushing: the pre-pressed massive boron nitride (BN column) is crushed and granulated, and the granulated particles are screened. (ii) a

(IV) forming: and (4) carrying out dry pressing molding on the particles sieved in the step (IV), and forming the BN sheet.

And (3) repeating the step (II) and the step (III) for 1 or more times.

In the step (one), when the boron nitride particles and the boron oxide are mixed, the mass ratio of the boron nitride is 88-98%. The boron nitride measuring method comprises the following steps: 1, grinding and crushing the boron nitride sheet; 2, taking 1g of powder into a beaker, and adding 100g of deionized water; 3, stirring the suspension and fully performing ultrasonic dispersion for 60 minutes; 4, pouring the suspension into a centrifuge tube, and centrifuging for 10min in a centrifuge at 10000 rpm; 5, separating solid from centrifugate; 6, drying the solid and weighing, wherein the ratio of the weight of the solid to 1g is the content of the boron nitride.

As can be seen from figure 3, with the increase of the number of times of pre-pressing and crushing, the density of BN flakes can be increased, when the number of times of pre-pressing and crushing is more than 3 times, the increase of the density of the BN flakes is very small, and the area is in a stable state, and the experimental result shows that the crushing and granulating link of the dry-mixing and dry-pressing process can be recycled, so that the production cost of the product can be reduced, and therefore, the number of times of pre-pressing and crushing is 1-3 times suitable for. Specific values are shown in table 1.

TABLE 1

As can be seen from fig. 4, there is a very slight tendency for the density of the BN sheet to increase with increasing pre-stress, and the density of the BN sheet is not very sensitive to the pre-stress. Specific values are shown in Table 2.

TABLE 2

As can be seen from fig. 5, the BN sheet density has a very slight increasing tendency as the BN sheet pressure increases; after 20KN, the density of the BN sheet is sensitive to the pressure of the BN sheet. Specific values are shown in Table 3.

TABLE 3

The above-mentioned embodiments are merely preferred embodiments for fully explaining the present invention, and the scope of the present invention is not limited thereto. The equivalent substitution or change made by the technical personnel in the technical field on the basis of the invention is all within the protection scope of the invention. The protection scope of the invention is subject to the claims.

Claims

1. A process for manufacturing a boron nitride block, comprising the steps of,

(III) crushing: crushing and granulating the pre-pressed massive boron nitride;

(IV) forming: and pressing and molding the boron nitride particles.

2. The manufacturing process of claim 1, wherein step (iii) further comprises sieving the granulated particles.

3. The manufacturing process according to claim 1, wherein the steps (two) and (three) are sequentially repeated 1 or more times before the step (four).

4. The manufacturing process according to claim 1, wherein in step (one), the boron nitride powder and the boric acid powder and/or the boron oxide powder are mixed under dry conditions.

5. The manufacturing process according to claim 2, wherein in step (three), the particle size of the sieved particles is 50 to 300 microns.

6. The manufacturing process according to claim 1, wherein in the step (one), the boron nitride is 88-98% by mass.

7. The manufacturing process of claim 1, wherein in step (one), the boron nitride has a hexagonal crystal structure.

8. The manufacturing process according to claim 5, wherein in step (one), the hexagonal boron nitride crystals have a particle size in the range of 0.1 to 50 μm.

9. A boron nitride block produced by the production process according to any one of claims 1 to 6.