CN109180221B

CN109180221B - Preparation method for depositing silicon carbide film on graphite template in large area

Info

Publication number: CN109180221B
Application number: CN201811255509.5A
Authority: CN
Inventors: 陈常连; 梁欣; 周诗聪; 季家友; 黄志良; 徐慢
Original assignee: Wuhan Institute of Technology
Current assignee: Wuhan Institute of Technology
Priority date: 2018-10-26
Filing date: 2018-10-26
Publication date: 2021-06-11
Anticipated expiration: 2038-10-26
Also published as: CN109180221A

Abstract

The invention discloses a preparation method for depositing a silicon carbide film on a graphite template in a large area, which comprises the steps of firstly mixing silicon nitride powder and silicon carbide powder according to a proper proportion, adding absolute ethyl alcohol to grind in a grinding bowl, cleaning, drying, then putting the powder into a sagger, and sintering in vacuum at the sintering temperature of more than 1900 ℃ for 1 h. The method has the advantages of controllable conditions, simple and convenient operation and mild reaction conditions, and the obtained silicon carbide film has large area and excellent stability, so that the service life of the graphite mold is greatly prolonged, a new way is provided for the glass heating graphite template modification technology, and the method has important economic and engineering values.

Description

Preparation method for depositing silicon carbide film on graphite template in large area

Technical Field

The invention belongs to the technical field of new materials, and particularly relates to a preparation method for depositing a silicon carbide film on a graphite template in a large area.

Background

With the advent of the flexible AMOLED and the 5G era, the 3D curved surface modeling and the glass material become standard configurations of mobile phones. The 3D curved surface screen can improve user visual experience, makes the visual angle wider, has certain stereoeffect, and the picture is 3D more.

The process of the 3D glass production and processing technology of the mobile phone mainly comprises the following steps: engineering → open material and open hole → fine carving → grinding → cleaning → hot bending → polishing → detection → tempering → mold opening → UV transfer → coating film (PVD) → printing (silk screen/spray coating) → laser carving → bag inspection → laminating → packaging, and the like, the process flow is long, the quality requirement is high, and the yield is low. The 3D glass hot bending molding is a molding process for heating glass to a specific temperature for softening, adopting a specific shape and copying a mold to obtain the required 3D shape glass. The hot bending process is one of the most central processes in the 3D glass manufacturing process and is also one of the difficulties. With the continuous investment of enterprises such as blues, berns, star science and technology, BYD and the like in 3D curved surface glass processing equipment and technology, a golden development period of 5 to 10 years is brought to 3D glass related equipment and material enterprises, the market capacity reaches 1000 hundred million yuan, only one of 3D curved surface key equipment, namely a gap of a hot bending machine is about 10000, and the market value is 100 hundred million yuan.

The graphite material has excellent heat conductivity and high temperature resistance, low linear expansion coefficient, good thermal stability and thermal shock resistance, good chemical stability, difficult infiltration by molten glass and no change of glass components, and is an ideal material for the glass high-temperature hot bending template. However, in the process of generating the curved glass by heating the graphite at high temperature, the surface of the graphite is easily oxidized to generate carbon monoxide and carbon dioxide, so that the size of the template is gradually reduced in the using process, the produced curved glass is unqualified in size, the surface of the curved glass is damaged, and the qualified rate of the curved glass is reduced. In recent years, a chemical vapor deposition method is commonly adopted for preparing the silicon carbide film, and the prepared film has good quality, but the method has certain limitation on depositing the silicon carbide film on the bulk graphite and has slow deposition speed. In the experiment, silicon nitride and silicon carbide powder are sintered by a vacuum evaporation method, and a stable and uniform silicon carbide film can be deposited on graphite in a large area.

Disclosure of Invention

In order to solve the defects of the prior art, the invention provides a preparation method for depositing a silicon carbide film on a graphite template in a large area.

The purpose of the invention is realized by the following technical scheme:

a preparation method for depositing a silicon carbide film on a graphite template in a large area comprises the following steps:

1) mixing silicon nitride powder and silicon carbide powder in proportion;

2) adding absolute ethyl alcohol into the powder obtained by the treatment of the step 1), cleaning and drying;

3) and (3) putting the powder obtained by the treatment in the step 2) into a sagger, covering a graphite substrate, and performing vacuum sintering to obtain the graphite substrate deposited with the silicon carbide film.

Furthermore, the particle size of the silicon nitride powder and the silicon carbide powder is 0.4-0.6 μm.

Further, the mass ratio of the silicon nitride powder to the silicon carbide powder is in the range of 1: 0.11 to 1: 0.25.

further, the sintering condition of the vacuum sintering is argon atmosphere, and the sintering is carried out under normal pressure.

Further, in the step 3), the sintering temperature is 1950-2100 ℃, and the temperature is kept for 0.5-1.5 hours to obtain the graphite substrate.

Furthermore, the thickness of the silicon carbide film deposited on the graphite substrate is 100-300 μm.

The invention has the beneficial effects that:

1) the obtained high-strength graphite template has large area and can be applied to various technological processes such as glass forming, hot press forming, sintering forming and the like.

2) The adopted raw materials are simple and easy to obtain, the cost is reduced, the related treatment steps are simple and convenient, the operability is strong, the reaction condition is controllable, and the engineering value is huge;

3) the graphite material treated by the method has excellent oxidation resistance, and the generated silicon carbide film is uniform, stable, strong in binding force, wear-resistant and high-temperature resistant.

Drawings

Fig. 1 is a schematic view showing the structure and size of a mold used in the present invention.

FIG. 2 is a scanning electron micrograph of example 1 of the present invention.

FIG. 3 is a scanning electron micrograph of example 2 of the present invention.

FIG. 4 is a SEM image of example 3 of the present invention.

Fig. 5 is a scanning electron micrograph of comparative example 1 of the present invention.

Fig. 6 is a scanning electron micrograph of comparative example 2 of the present invention.

Fig. 7 is a scanning electron micrograph of comparative example 3 of the present invention.

Detailed Description

The principles and features of this invention are described below in conjunction with the following drawings, which are set forth to illustrate, but are not to be construed to limit the scope of the invention.

In the following examples, silicon nitride is provided by Shanghai Seawa technologies, Inc. The silicon carbide used was supplied by Shanghai field science and technology, Inc. The absolute ethanol used was provided by Shanghai Wokka Biotechnology Co., Ltd. The graphite mold used was supplied by south sea Bao carbon graphite products, Inc. of Foshan.

Example 1

Taking 6.3g of silicon nitride and 0.7g of silicon carbide, adding a proper amount of absolute ethyl alcohol, fully and uniformly grinding in a mortar, then putting the mixture into a blast drier, drying at 100 ℃ for 1h, then putting into a graphite sagger, covering a graphite substrate, carrying out vacuum evaporation in a silicon carbide sintering furnace, wherein the evaporation temperature is 1950 ℃, and keeping the temperature for 0.5 h. Obtaining the graphite substrate plated with the compact silicon carbide film.

Example 2

Taking 5.9g of silicon nitride and 1.1g of silicon carbide, adding a proper amount of absolute ethyl alcohol, fully and uniformly grinding in a mortar, then putting the mixed materials into a blast drier, drying at 100 ℃ for 1h, then putting into a graphite sagger, covering a graphite substrate, carrying out vacuum evaporation in a silicon carbide sintering furnace, wherein the evaporation temperature is 2000 ℃, and keeping the temperature for 1 h. Obtaining the graphite substrate plated with the compact silicon carbide film.

Example 3

Taking 5.6g of silicon nitride and 1.4g of silicon carbide, adding a proper amount of absolute ethyl alcohol, fully and uniformly grinding in a mortar, then putting the mixed materials into a forced air drier, drying at 100 ℃ for 1h, then putting into a graphite sagger, covering a graphite substrate, carrying out vacuum evaporation in a silicon carbide sintering furnace, wherein the evaporation temperature is 2100 ℃, and keeping the temperature for 1.5 h. Obtaining the graphite substrate plated with the compact silicon carbide film.

Comparative example 1

Taking 1.8g of silicon nitride and 1.2g of silicon carbide, adding a proper amount of absolute ethyl alcohol, fully and uniformly grinding in a mortar, then putting the mixed materials into a blast drier, drying at 100 ℃ for 1h, then putting into a graphite sagger, covering a graphite substrate, carrying out vacuum evaporation in a silicon carbide sintering furnace, wherein the evaporation temperature is 2000 ℃, and keeping the temperature for 1 h. The graphite substrate with part of silicon carbide particles on the surface is obtained.

Comparative example 2

Taking 4.2g of silicon nitride and 2.8g of silicon carbide, adding a proper amount of absolute ethyl alcohol, fully and uniformly grinding in a mortar, then putting the mixed materials into a blast drier, drying at 100 ℃ for 1h, then putting into a graphite sagger, covering a graphite substrate, carrying out vacuum evaporation in a silicon carbide sintering furnace, wherein the evaporation temperature is 2130 ℃, and keeping the temperature for 1 h. Obtaining the graphite substrate with the silicon carbide whiskers and the silicon carbide particles attached to the surface.

Comparative example 3

Taking 8g of silicon nitride, adding a proper amount of absolute ethyl alcohol, fully and uniformly grinding in a mortar, then putting the mixed material into a forced air dryer, drying at 100 ℃ for 1h, then putting into a graphite sagger, covering a graphite substrate, carrying out vacuum evaporation in a silicon carbide sintering furnace, carrying out evaporation at the evaporation temperature of 2000 ℃, and keeping the temperature for 1 h. The obtained silicon carbide particles are regular and have edges and corners, and the sintered neck is not completely developed.

Comparative example 4

Yi Bo Wen adopts isothermal and isobaric chemical vapor deposition technology, CH3SiCl3-H2 and SiCl4-CH4-H2 are respectively used as gas sources, and the pure SiC film is prepared under the conditions of deposition temperature 1100, 1000 ℃ and pressure 101kPa, the average gas residence time l s and the deposition time 32H. The substrate size is small, 20mm by 40mm, and the deposition time is too long.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A preparation method for depositing a silicon carbide film on a graphite template in a large area is characterized by comprising the following steps:

1) mixing silicon nitride powder and silicon carbide powder according to a mass ratio, wherein the mass ratio of the silicon nitride powder to the silicon carbide powder is 1: 0.11 to 1: 0.25;

2) adding absolute ethyl alcohol into the powder obtained by the treatment in the step 1), cleaning and drying;

3) and (3) putting the powder obtained by the treatment in the step 2) into a sagger, covering a graphite substrate, and performing vacuum sintering at the evaporation temperature of 1950-2100 ℃ for 0.5-1.5 h to obtain the graphite substrate.

2. The method for preparing the silicon carbide film deposited on the graphite template in the large area according to claim 1, wherein the particle sizes of the silicon nitride powder and the silicon carbide powder are 0.4-0.6 μm.

3. The method for preparing large-area silicon carbide film on graphite template according to claim 1, wherein the sintering condition of vacuum sintering is argon atmosphere.

4. The method for preparing a silicon carbide film deposited on a graphite template in a large area according to claim 1, wherein the silicon carbide film deposited on the graphite substrate has a thickness of 100 μm to 300 μm.

5. A graphite template prepared by the preparation method for depositing the silicon carbide film on the graphite template in a large area according to any one of claims 1 to 4.