Device and method for preparing multi-layer multi-party boron nitride

Abstract

The device comprises a left material tank (10), a middle material tank (7) and a right material tank (2), heating devices are arranged below the left material tank (10), the middle material tank (7) and the right material tank (2) respectively and comprise a left heating table (12), a middle heating table (5) and a right heating table (1), left conveying pipes (9) are arranged above the left material tank (10) and the right material tank (2) respectively, right conveying pipes (4) are connected with the middle material tank (7), and the left conveying pipes (9) are connected with the middle material tank (7). An air channel (8) is arranged above the middle material tank (7) and is communicated with the atmosphere; according to the device, phase flow and reaction are controlled by virtue of three heating tables and one air passage in different heating temperature intervals and by virtue of air pressure difference, so that the preparation of the multi-layer multi-party boron nitride coating is realized.

Description

Technical Field

[0001] The invention discloses a device and a method for preparing multi-layer polyhedral boron nitride, belonging to the technical field of composite material molding. Background Art

[0002] Foreign countries have been committed to developing borides as catalysts for the production of hydrogen and oxygen in the chemical industry. Nano metal borides are usually produced using thermal plasma, but this method has harsh temperature conditions and requires complex equipment. Impurities and defects in the prepared materials will damage their properties. Therefore, achieving high purity of borides is one of the key technical factors. Among many borides, boron nitride has multiple uses, but the synthesis of high-purity boron nitride is still very difficult. Summary of the invention

[0003] The present invention is designed to address the above-mentioned prior art situation and provides a device and method for preparing a multi-layer polygonal boron nitride, the purpose of which is to prepare a polygonal boron nitride protective coating on a metal surface to improve the wear resistance of the surface.

[0004] To achieve the above purpose, the technical solution of the present invention is as follows:

[0005] In the preparation device and method of multilayer polyhedral boron nitride proposed in the technical solution of the present invention, the device includes a left material tank 10, a middle material tank 7, and a right material tank 2. A heating device is arranged under each material tank, which are a left heating table 12, a middle heating table 5, and a right heating table 1. A left conveying pipe 9 and a right conveying pipe 4 are respectively arranged above the left material tank 10 and the right material tank 2 to connect to the middle material tank 7. An airway 8 is arranged above the middle material tank 7 to communicate with the atmosphere;

[0006] The steps of preparing multilayer polyhedral boron nitride using the above device are as follows:

[0007] Step 1: Material preparation

[0008] Boronized carbon particles 11 are placed in the left material tank 10, and the particle size of the boronized carbon particles is -400 to -500 mesh; a titanium alloy plate 6 is placed in the middle material tank 7, and the thickness of the titanium alloy plate 6 is greater than 20 mm and less than 1 / 3 of the height of the inner cavity of the middle material tank 7, and a layer of silicon carbide is evenly laid on the upper surface of the titanium alloy plate 6, and the thickness of the silicon carbide layer is 1 / 10 of the thickness of the titanium alloy plate 6; metal tungsten particles 3 are placed in the right material tank 2, and the particle size of the metal tungsten particles is -400 to -500 mesh;

[0009] Step 2: Preparation of multi-layered polyhedral boron nitride substrate

[0010] Start the left heating stage 12 and the right heating stage 1, heat to 800-1000°C and keep warm. After keeping warm for 1-2 hours, the air temperature in the three material tanks reaches 800-1000°C, start the middle heating stage 5, and quickly heat the silicon carbide on the surface of the titanium alloy plate 6 to 1800°C. The silicon carbide on the surface of the titanium alloy plate 6 is decomposed by the instantaneous joint action of the upper and lower heat sources. The temperature of the titanium alloy plate 6 does not exceed 1000°C by heat exchange. Since the air pressure in the left material tank 10 and the right material tank 2 is higher than that in the middle material tank 7, silicon evaporates from the surface of the titanium alloy plate 6 and is discharged from the middle material tank 7 through the air duct 8. The remaining carbon on the surface of the titanium alloy plate 6 is rearranged to form graphene, and a multi-layered polyhedral boron nitride-based protective layer is formed on the surface of the titanium alloy plate 6.

[0011] Step 3: Preparation of Polygonal Boron Nitride

[0012] Nitrogen is delivered to the middle material tank 7 through the air passage 8, so that the inside of the middle material tank 7 is positively pressurized, but still lower than the air pressure in the left material tank 10 and the right material tank 2. At the same time, the temperature of the left heating platform 12 and the right heating platform 1 is increased to 1200-1800°C, so that the boronized carbon particles 11 in the left material tank 10 and the metal tungsten particles 3 in the right material tank 2 are decomposed and volatilized by heat to form boron and tungsten gases, respectively. As the gas pressure in the left material tank 10 and the right material tank 2 increases, the boron and tungsten gases enter the middle material tank 7 along the left delivery pipe 9 and the right delivery pipe 4, respectively, and are mixed with nitrogen to generate W-BN. At this time, the temperature of the middle heating platform 5 is reduced to make the W-BN fall on the protective layer on the surface of the titanium alloy plate 6. Since the volatilization of boron is random and the combination with nitrogen is also random, the generated W-BN is multi-party. When the deposition thickness of W-BN is consistent with the thickness of the protective layer on the surface of the titanium alloy plate 6, the left heating platform 12, the middle heating platform 5 and the right heating platform 1 are closed;

[0013] Step 4: Preparation of multilayer polyhedral boron nitride

[0014] Repeat steps 2 and 3 to obtain multi-layered polyhedral boron nitride, and then take out the titanium alloy plate 6 cooled to room temperature.

[0015] During implementation, in step 4, after the titanium alloy plate 6 cooled to room temperature is taken out, the multi-layered polygonal boron nitride layer on its surface is molded at a pressure not greater than 1 MPa.

[0016] The characteristics and beneficial effects of the technical solution of the present invention are:

[0017] First, a protective coating for metal surface is prepared by the scheme of the present invention. The coating is a polyhedral boron nitride, in which tungsten nanoparticles are interspersed, so that it has a certain wear resistance;

[0018] Second, in the present invention, silicon carbide is heated to high temperatures, causing a thin layer of silicon to evaporate from the surface, leaving the carbon behind to rearrange to form graphene, forming a protective layer on the material. The graphene and silicon carbide interface is only partially stable, which means that when holes are poked in the graphene and pure metal powder is evaporated onto the surface at high temperatures, the metal is pulled into the holes in a process similar to capillary action. These metals are conductive, even superconducting, but can become insulators through oxidation - the same process that metals rust when exposed to air;

[0019] 3. The device of the present invention is different from conventional process equipment such as vapor deposition and ion spraying. The device of the present invention only relies on three heating stages and one gas channel. In different heating temperature ranges, the pressure difference is used to control the flow and reaction of the phases, thereby realizing the preparation of multi-layer polyhedral boron nitride coatings.

[0020] Fourth, the apparatus of the present invention can achieve mutual matching of four phases of carbon, boron, nitrogen and tungsten. First, carbon is used as a substrate and is the first phase to be obtained. Secondly, nitrogen, a second phase, is introduced as a reserve for reaction with boron, and its concentration is adjustable. Thirdly, boron is used as another reserve for reaction with nitrogen and can be obtained by heating. Finally, tungsten is used as a reinforcing particle and can be obtained by heating. The above four phases can react and deposit sequentially or simultaneously by virtue of the time and concentration of reaction generation, thereby forming products of different levels.

[0021] 5. In the scheme of the present invention, by adjusting the concentration of nitrogen and the concentration of boron, boron nitride with different structures can be obtained. In addition, under the action of part of tungsten and carbon, the structure of the final coating phase can also be changed, which has high flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the device described in the technical solution of the present invention DETAILED DESCRIPTION

[0023] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments:

[0024] See attached Figure 1 As shown, the preparation device of multilayer polyhedral boron nitride proposed in the technical solution of the present invention comprises a left material tank 10, a middle material tank 7, and a right material tank 2. A heating device is arranged under each material tank, namely a left heating platform 12, a middle heating platform 5, and a right heating platform 1. A left conveying pipe 9 and a right conveying pipe 4 are respectively arranged above the left material tank 10 and the right material tank 2 to connect to the middle material tank 7. An airway 8 is arranged above the middle material tank 7 to communicate with the atmosphere.

[0025] The steps of preparing multilayer polyhedral boron nitride using the above device are as follows:

[0026] Step 1: Material preparation

[0027] Boronized carbon particles 11 are placed in the left material tank 10, and the particle size of the boronized carbon particles is -400 to -500 mesh; a titanium alloy plate 6 is placed in the middle material tank 7, and the thickness of the titanium alloy plate 6 is greater than 20 mm and less than 1 / 3 of the height of the inner cavity of the middle material tank 7, and a layer of silicon carbide is evenly laid on the upper surface of the titanium alloy plate 6, and the thickness of the silicon carbide layer is 1 / 10 of the thickness of the titanium alloy plate 6; metal tungsten particles 3 are placed in the right material tank 2, and the particle size of the metal tungsten particles is -400 to -500 mesh;

[0028] Step 2: Preparation of multi-layered polyhedral boron nitride substrate

[0029] Start the left heating stage 12 and the right heating stage 1, heat to 800-1000°C and keep warm. After keeping warm for 1-2 hours, the air temperature in the three material tanks reaches 800-1000°C, start the middle heating stage 5, and quickly heat the silicon carbide on the surface of the titanium alloy plate 6 to 1800°C. The silicon carbide on the surface of the titanium alloy plate 6 is decomposed by the instantaneous joint action of the upper and lower heat sources. The temperature of the titanium alloy plate 6 does not exceed 1000°C by heat exchange. Since the air pressure in the left material tank 10 and the right material tank 2 is higher than that in the middle material tank 7, silicon evaporates from the surface of the titanium alloy plate 6 and is discharged from the middle material tank 7 through the air duct 8. The remaining carbon on the surface of the titanium alloy plate 6 is rearranged to form graphene, and a multi-layered polyhedral boron nitride-based protective layer is formed on the surface of the titanium alloy plate 6.

[0030] Step 3: Preparation of Polygonal Boron Nitride

[0031] Nitrogen is delivered to the middle material tank 7 through the air passage 8, so that the inside of the middle material tank 7 is positively pressurized, but still lower than the air pressure in the left material tank 10 and the right material tank 2. At the same time, the temperature of the left heating platform 12 and the right heating platform 1 is increased to 1200-1800°C, so that the boronized carbon particles 11 in the left material tank 10 and the metal tungsten particles 3 in the right material tank 2 are decomposed and volatilized by heat to form boron and tungsten gases, respectively. As the gas pressure in the left material tank 10 and the right material tank 2 increases, the boron and tungsten gases enter the middle material tank 7 along the left delivery pipe 9 and the right delivery pipe 4, respectively, and are mixed with nitrogen to generate W-BN. At this time, the temperature of the middle heating platform 5 is reduced to make the W-BN fall on the protective layer on the surface of the titanium alloy plate 6. Since the volatilization of boron is random and the combination with nitrogen is also random, the generated W-BN is multi-party. When the deposition thickness of W-BN is consistent with the thickness of the protective layer on the surface of the titanium alloy plate 6, the left heating platform 12, the middle heating platform 5 and the right heating platform 1 are closed;

[0032] Step 4: Preparation of multilayer polyhedral boron nitride

[0033] Repeat steps 2 and 3 to obtain multi-layered polygonal boron nitride, and then take out the titanium alloy plate 6 cooled to room temperature. After taking out the titanium alloy plate 6 cooled to room temperature, the multi-layered polygonal boron nitride layer on its surface is molded at a pressure of no more than 1 MPa. In this embodiment, the hardness of the polygonal boron nitride protective coating obtained on the surface of the titanium alloy plate 6 can reach HV0.03 and reach 1200-1500.

Claims

1. A preparation device and method for multilayer polyhedral boron nitride, characterized in that: The device comprises a left material tank (10), a middle material tank (7), and a right material tank (2). A heating device is arranged below each material tank, namely a left heating platform (12), a middle heating platform (5), and a right heating platform (1). A left conveying pipe (9) and a right conveying pipe (4) are arranged above the left material tank (10) and the right material tank (2) to connect to the middle material tank (7). An airway (8) is arranged above the middle material tank (7) to communicate with the atmosphere. The steps of preparing multilayer polyhedral boron nitride using the above device are as follows: Step 1: Material preparation Boronized carbon particles (11) are placed in the left material tank (10), and the particle size of the boronized carbon particles is -400 to -500 mesh; a titanium alloy plate (6) is placed in the middle material tank (7), and the thickness of the titanium alloy plate (6) is greater than 20 mm and less than 1 / 3 of the height of the inner cavity of the middle material tank (7); a layer of silicon carbide is evenly laid on the upper surface of the titanium alloy plate (6), and the thickness of the silicon carbide layer is 1 / 10 of the thickness of the titanium alloy plate (6); metal tungsten particles (3) are placed in the right material tank (2), and the particle size of the metal tungsten particles is -400 to -500 mesh; Step 2: Preparation of multi-layered polyhedral boron nitride substrate The left heating platform (12) and the right heating platform (1) are started, and the heating temperature is 800-1000°C and maintained. After maintaining the temperature for 1-2 hours, the air temperature in the three material tanks reaches 800-1000°C. The middle heating platform (5) is started to quickly heat the silicon carbide on the surface of the titanium alloy plate (6) to 1800°C. The silicon carbide on the surface of the titanium alloy plate (6) is decomposed by the instantaneous combined action of the upper and lower heat sources. The temperature of the titanium alloy plate (6) does not exceed 1000°C by virtue of heat exchange. Since the air pressure in the left material tank (10) and the right material tank (2) is higher than that in the middle material tank (7), silicon evaporates from the surface of the titanium alloy plate (6) and is discharged from the middle material tank (7) through the air duct (8). The remaining carbon on the surface of the titanium alloy plate (6) is rearranged to form graphene, and a multi-layered polyhedral boron nitride-based protective layer is formed on the surface of the titanium alloy plate (6); Step 3: Preparation of Polygonal Boron Nitride Nitrogen is delivered to the middle material tank (7) through the air passage (8) so that the inside of the middle material tank (7) is at a positive pressure, but still lower than the air pressure in the left material tank (10) and the right material tank (2). At the same time, the temperature of the left heating platform (12) and the right heating platform (1) is increased to 1200-1800° C., so that the boronized carbon particles (11) in the left material tank (10) and the metal tungsten particles (3) in the right material tank (2) are decomposed and volatilized by heat to form boron and tungsten gases respectively. As the gas pressure in the left material tank (10) and the right material tank (2) increases, Boron and tungsten gases enter the middle material tank (7) along the left conveying pipe (9) and the right conveying pipe (4) respectively, and are mixed with nitrogen to generate W-BN. At this time, the temperature of the middle heating platform (5) is lowered to allow the W-BN to fall on the protective layer on the surface of the titanium alloy plate (6). Since the volatilization of boron is random and the combination with nitrogen is also random, the generated W-BN is multi-faceted. When the deposition thickness of the W-BN is consistent with the thickness of the protective layer on the surface of the titanium alloy plate (6), the left heating platform (12), the middle heating platform (5) and the right heating platform (1) are closed; Step 4: Preparation of multilayer polyhedral boron nitride Repeat steps 2 and 3 to obtain multi-layered polyhedral boron nitride, and then take out the titanium alloy plate (6) cooled to room temperature.

2. The device and method for preparing multilayer polyhedral boron nitride according to claim 1, characterized in that: In step 4, after the titanium alloy plate (6) is taken out and cooled to room temperature, the multi-layered polygonal boron nitride layer on its surface is molded at a pressure not greater than 1 MPa.

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