Silicon crystal furnace resistant to silicon element corrosion

Abstract

A silicon crystal furnace resistant to silicon corrosion includes a furnace body. The thermal structural material of the furnace body is a C / C composite material. The surface of the C / C composite material is coated with a silicon corrosion resistant coating made of zirconium silicate. This silicon corrosion resistant coating is prepared by: placing the C / C composite material in a sandblasting machine and sandblasting the surface of the C / C composite material with sand particles selected from silicon carbide particles, alumina particles, and quartz sand; then, using zirconium silicate as a granulated agglomerate, spraying the surface of the C / C composite material with atmospheric plasma to form the silicon corrosion resistant coating. In this invention, the silicon crystal furnace, wherein the surface of the C / C composite material used as the thermal structural material is coated with a silicon corrosion resistant coating made of zirconium silicate, provides excellent resistance to silicon corrosion, silica corrosion, and silica monoxide corrosion. This prevents the thermal structural material from undergoing a silanization reaction under high-temperature conditions, thus affecting the stability of the thermal field and improving the service life of the silicon crystal furnace.

Description

Technical Field

[0001] This invention relates to the field of inorganic non-metallic composite materials technology, and specifically to a silicon crystal furnace resistant to silicon corrosion. Background Technology

[0002] Silicon solar cells dominate the market, with monocrystalline and polycrystalline silicon forming the material basis for their photoelectric conversion. In the preparation of crystalline silicon, C / C composite materials, due to their high strength, low coefficient of thermal expansion, impact resistance, high modulus, and corrosion resistance, have become ideal structural materials in the thermal field of crystalline silicon furnaces (also known as monocrystalline silicon furnaces). In the actual production process of crystalline silicon materials, due to the high temperature, the quartz crucible used to hold the silicon material and the molten silicon material both volatilize and generate large amounts of SiO2 and Si vapor. When these gases come into contact with the carbon-based thermal field materials, they easily undergo silanization reactions, resulting in corrosion. This corrosion can cause serious damage to the materials, thus affecting the stability of the thermal field and posing safety hazards to the crystalline silicon furnace equipment.

[0003] A chemical reaction occurs between carbon and silicon above 1150℃. Monocrystalline silicon is produced at temperatures above 1450℃. Under these conditions, the Gibbs free energy for the reaction to form silicon carbide is approximately -61 kJ. This means that molten silicon droplets or silicon vapor will react instantly upon contact with carbon thermal field materials. The chemical equation for the reaction is:

[0004] C(s) + Si(g) → SiC(s).

[0005] Under these environmental conditions, SiO2 vapor reacts with the C / C crucible sides. The chemical equation for the reaction is as follows:

[0006] 3C(s) + SiO2(g) → SiC(s) + 2CO(s)

[0007] C(s) + SiO₂(g) → SiO(g) + CO(g)

[0008] The generated SiO vapor will also adhere to the surface of the thermal field material and react with the carbon thermal field material. The chemical equation for the reaction is:

[0009] 3C(s)+SiO(g)→SiC(s)+2CO(s). Summary of the Invention

[0010] Based on this, the present invention provides a silicon crystal furnace resistant to silicon element corrosion, in order to solve the technical problem that the carbon-based thermal field material of the existing silicon crystal furnace will be corroded due to the siliconization reaction when producing crystalline silicon materials under high temperature conditions.

[0011] To achieve the above objectives, the present invention provides a silicon crystal furnace resistant to silicon corrosion, comprising a silicon crystal furnace body, wherein the thermal structural material of the silicon crystal furnace body is a C / C composite material, characterized in that the surface of the C / C composite material is provided with a silicon corrosion resistant coating made of zirconium silicate, and the silicon corrosion resistant coating is prepared on the surface of the C / C composite material by the following method:

[0012] The C / C composite material is placed in a sandblasting machine, and any one of the following abrasive particles—silicon carbide particles, alumina particles, or quartz sand—is selected to sandblast the surface of the C / C composite material. Then, zirconium silicate with a particle size of 400-600 mesh is selected as the agglomerate and atmospheric plasma spraying is applied to the surface of the C / C composite material to form a silicon-resistant coating.

[0013] As a further preferred embodiment of the present invention, the thickness of the silicon-resistant coating is 10-100 μm.

[0014] As a further preferred embodiment of the present invention, the density of the C / C composite material is 1.4 g / cm³. 3 ~1.6g / cm 3 .

[0015] As a further preferred embodiment of the present invention, the process of placing the C / C composite material into the sandblasting machine includes:

[0016] The cut C / C composite material is placed in an ultrasonic cleaner for ultrasonic cleaning, and then placed in an oven for drying.

[0017] As a further preferred embodiment of the present invention, the ultrasonic cleaning reagent is any one of alcohol, acetone, and water; the ultrasonic cleaning time is 5 to 20 minutes; and the drying time in the oven is 6 to 18 hours.

[0018] As a further preferred technical solution of the present invention, the particle size of the sand used in the sandblasting treatment is 50 mesh to 80 mesh; the sandblasting time is 3s to 8s.

[0019] As a further preferred technical solution of the present invention, in the atmospheric plasma spraying process, the current used is 300A to 450A, the voltage used is 75V to 90V, the argon flow rate is 30L / min to 45L / min, the hydrogen flow rate is 5L / min to 8L / min, and the distance between the spray gun and the C / C composite material is 10cm to 15cm.

[0020] As a further preferred technical solution of the present invention, atmospheric plasma spraying is performed once, and the spraying time is 2 seconds.

[0021] The silicon crystal furnace resistant to silicon element corrosion of the present invention, by adopting the above technical solution, can achieve the following beneficial effects:

[0022] 1) In the silicon crystal furnace of the present invention, the surface of the C / C composite material used as the thermal structure material is provided with a silicon element corrosion resistant coating made of zirconium silicate, which gives it good anti-silicon corrosion, anti-silicon dioxide corrosion and anti-silicon monoxide corrosion effect, avoids the thermal structure material from undergoing silicification reaction under high temperature conditions and affecting the stability of the thermal field, thereby improving the service life of the silicon crystal furnace.

[0023] 2) This invention uses atmospheric plasma spraying to prepare a silicon-resistant coating on the C / C surface. The process is efficient and fast, with high feasibility. The spraying process parameters can be quantitatively controlled, the process is stable, the coating has good reproducibility, and the coating quality is high.

[0024] 3) The silicon-resistant coating of the present invention is uniform, dense and continuous, and has excellent silicon-resistant corrosion resistance, which can significantly improve the silicon-resistant corrosion resistance of C / C composite materials.

[0025] 4) The zirconium silicate used in the silicon-resistant coating of this invention is a common chemical raw material. The raw material is cheap and readily available, resulting in low cost. Attached Figure Description

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0027] Figure 1 The images show the morphology and XRD pattern of the C / C thermal structural material prepared in Comparative Example 1 after being corroded by silicon powder. In the images, a is the cross-sectional micromorphology of the C / C composite material sample after being corroded by silicon powder, b is the macromorphology of the C / C composite material sample after being corroded by silicon powder, and c is the XRD pattern of the C / C composite material sample after being corroded by silicon powder.

[0028] Figure 2 The images show the morphology and XRD pattern of the C / C thermal structural material prepared in Comparative Example 1 after being corroded by silica powder. a is a cross-sectional SEM micro-morphology of the C / C composite material sample after being corroded by silica powder, b is a macro-morphology of the C / C composite material sample after being corroded by silica powder, and c is an XRD pattern of the C / C composite material sample after being corroded by silica powder.

[0029] Figure 3 The images show the morphology and XRD pattern of the C / C thermal structural material prepared in Comparative Example 1 after being corroded by silica powder. a is the cross-sectional micromorphology of the C / C composite material sample after being corroded by silica powder, b is the macromorphology of the C / C composite material sample after being corroded by silica powder, and c is the XRD pattern of the C / C composite material sample after being corroded by silica powder.

[0030] Figure 4This is a process flow diagram of the method for preparing a silicon-resistant coating on the surface of a C / C composite material according to the present invention;

[0031] Figure 5 The images shown are macroscopic images and cross-sectional microstructures of the C / C composite material with an atmospheric plasma-sprayed boron nitride coating in Comparative Example 2. Image a is a macroscopic image of the C / C composite material with the atmospheric plasma-sprayed boron nitride coating; image b is a microstructure of the atmospheric plasma-sprayed boron nitride coating; image c is a Si element distribution diagram of the C / C composite material with the atmospheric plasma-sprayed boron nitride coating after high-temperature corrosion by silicon powder; and image d is a Si element distribution diagram of the C / C composite material with the atmospheric plasma-sprayed boron nitride coating after high-temperature corrosion by silicon dioxide powder.

[0032] Figure 6 The images shown are macroscopic images and cross-sectional microstructures of the C / C composite material with atmospheric plasma-sprayed silicon nitride coating, as shown in Comparative Example 3. a) Macroscopic image of the C / C composite material with atmospheric plasma-sprayed silicon nitride coating; b) Microstructure of the atmospheric plasma-sprayed silicon nitride coating; c) Silicon element distribution diagram of the C / C composite material with atmospheric plasma-sprayed silicon nitride coating after high-temperature corrosion by silicon powder; d) Silicon element distribution diagram of the C / C composite material with atmospheric plasma-sprayed silicon nitride coating after high-temperature corrosion by silicon monoxide powder.

[0033] Figure 7 The images show the cross-sectional microstructure and Zr element energy spectrum of the C / C composite material with atmospheric plasma spraying of zirconium silicate coating in Example 1, where a is the cross-sectional microstructure of the C / C composite material with atmospheric plasma spraying of zirconium silicate coating, and b is the cross-sectional Zr element energy spectrum of the C / C composite material with atmospheric plasma spraying of zirconium silicate coating.

[0034] Figure 8 The images show the cross-sectional microstructure and energy dispersive spectroscopy (EDS) of the C / C composite material with atmospheric plasma-sprayed zirconium silicate coating etched by silicon powder in Example 1. Image a shows the cross-sectional microstructure of the C / C composite material with atmospheric plasma-sprayed zirconium silicate coating etched by silicon powder, and image b shows the cross-sectional EDS of the C / C composite material with atmospheric plasma-sprayed zirconium silicate coating etched by silicon powder.

[0035] Figure 9 The images show the cross-sectional microstructure and Zr elemental energy spectrum of the C / C composite material with atmospheric plasma-sprayed zirconium silicate coating in Example 2. Image a shows the cross-sectional microstructure of the C / C composite material with atmospheric plasma-sprayed zirconium silicate coating, and image b shows the cross-sectional Zr elemental energy spectrum of the C / C composite material with atmospheric plasma-sprayed zirconium silicate coating.

[0036] Figure 10The images show the cross-sectional microstructure and cross-sectional Si element energy spectrum of the C / C composite material with atmospheric plasma sprayed zirconium silicate coating corroded by silica powder in Example 1. In example 1, a is the cross-sectional microstructure of the C / C composite material with atmospheric plasma sprayed zirconium silicate coating corroded by silica powder, and b is the cross-sectional Si element energy spectrum of the C / C composite material with atmospheric plasma sprayed zirconium silicate coating corroded by silica powder.

[0037] Figure 11 The images show the cross-sectional microstructure and Zr element energy spectrum of the C / C composite material with atmospheric plasma spraying of zirconium silicate coating in Example 3, where a is the cross-sectional microstructure of the C / C composite material with atmospheric plasma spraying of zirconium silicate coating, and b is the cross-sectional Zr element energy spectrum of the C / C composite material with atmospheric plasma spraying of zirconium silicate coating.

[0038] Figure 12 The images show the cross-sectional microstructure and energy dispersive spectroscopy (EDS) of the C / C composite material with an atmospheric plasma-sprayed zirconium silicate coating, which was corroded by silica powder in Example 1. Image a shows the cross-sectional microstructure of the C / C composite material with an atmospheric plasma-sprayed zirconium silicate coating, which was corroded by silica powder. Image b shows the cross-sectional EDS of the C / C composite material with an atmospheric plasma-sprayed zirconium silicate coating, which was corroded by silica powder.

[0039] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0040] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0041] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0042] The thermal structure materials of the silicon crystal furnace in this invention include crucibles, flow guides, insulation covers, pressure rings, insulation hoods, furnace bottom guards, and other components or partial components thereof made of C / C composite material. Of course, other structural components within the silicon crystal furnace made of C / C composite material can also be used, and are not limited here. The carbon / carbon crucible primarily supports and rotates the quartz crucible at high temperatures; the flow guide is mainly used to control the temperature gradient of the thermal field and guide the argon gas flow, playing a supporting and insulating role in the single-crystal silicon pulling furnace. This insulating cylinder consists of a support cylinder wrapped with cured carbon felt, and its function is to retain heat and reduce heat loss within the crucible. The use of C / C composite material as a thermal structure material is a conventional technology for silicon crystal furnaces (see "Application Analysis of C / C Composite Material Crucibles for Single-Crystal Silicon Furnaces" by Hu Zhenying). 1,2 Meng Fancai 2 Peng Zhigang 1 Zhang Yonghui 1 Zhao Shangyuan 1 Fan Zhenning 1 Su Junming 1,2 Xie Yingzi 12 Chen Qinghua 12 ;1 Xi’an Chaoma Technology Co., Ltd., Xi’an 710025; 2 National and Local Joint Engineering Research Center for High-Performance Carbon Fiber Manufacturing and Application, Xi’an 710089), whose detailed structure will not be described here.

[0043] In the following comparative examples and embodiments, the thermal structure material of the silicon crystal furnace is a carbon / carbon (C / C) crucible.

[0044] Comparative Example 1:

[0045] The silicon crystal furnace provided in this comparative example is not resistant to silicon corrosion. It includes a silicon crystal furnace body, and the thermal structural material of the silicon crystal furnace body is a C / C composite material, which is prepared in the following manner:

[0046] The cut C / C composite material was placed in an ultrasonic cleaner for ultrasonic cleaning for 5 minutes, and then placed in an oven to dry for 8 hours.

[0047] The silicon corrosion resistance of the C / C composite material prepared above was tested:

[0048] Three dried C / C composite material samples were taken out and embedded with Si, SiO and SiO2 powders respectively on their surfaces. They were then placed in tube furnaces and etched at 1500℃ for 2h under an argon atmosphere to obtain the surface microstructure of the C / C composite material after silicon etching.

[0049] Figure 1 The image shows the morphology of the C / C thermal structure material prepared in Comparative Example 1 after etching with silicon powder. Figure 1a is a cross-sectional microstructure of the C / C composite sample after it was corroded by silicon powder. Figure 1 b is a macroscopic morphology image of the C / C composite sample after it has been corroded by silicon powder. Figure 1 c shows the XRD pattern of the C / C composite sample after it was etched by silicon powder. The figure shows that the surface of the C / C composite was etched by silicon powder, forming a large amount of SiC, with a small amount of residual Si on the surface.

[0050] Figure 2 The image shows the morphology of the C / C thermal structural material prepared in Comparative Example 1 after etching with silica powder. Figure 2 a is a SEM microstructure of the cross-section of the C / C composite material sample after it was corroded by silica powder. Figure 2 b is a macroscopic morphology image of the C / C composite sample after it has been corroded by silica powder. Figure 2 c represents the XRD pattern of the C / C composite sample after it was etched by silica powder. Figure 2 It can be seen that, due to the volatilization of SiO at this temperature, the surface of the C / C composite material is partially corroded by silicon, forming a small amount of SiC.

[0051] Figure 3 The image shows the morphology of the C / C thermal structural material prepared in Comparative Example 1 after etching with silica powder. Figure 3 a is a cross-sectional microstructure of the C / C composite sample after it was corroded by silica powder. Figure 3 b is a macroscopic morphology image of the C / C composite material sample after it has been corroded by silica powder. Figure 3 c represents the XRD pattern of the C / C composite sample after it was corroded by silica powder. Figure 3 It can be seen that, due to the volatilization of SiO2 at this temperature, the surface of the C / C composite material is almost not corroded by silicon, and almost no SiC is found. There is a small amount of residual SiO2 on the surface.

[0052] Comparative Example 2:

[0053] The silicon crystal furnace provided in this comparative example has poor resistance to silicon element corrosion. It includes a silicon crystal furnace body, the thermal structural material of which is a C / C composite material. A boron nitride coating is applied to the surface of the C / C composite material. The boron nitride coating is prepared on the C / C composite material in the following manner:

[0054] (1) Ultrasonic cleaning and drying of C / C composite material: The cut C / C composite material was placed in an ultrasonic cleaner and ultrasonically cleaned for 6 minutes, and then placed in an oven to dry for 9 hours.

[0055] (2) Sandblasting of C / C composite material surface: The C / C composite material from step (1) is placed in a sandblasting machine for sandblasting treatment. The sand particles used for sandblasting are silicon carbide particles with a particle size of 50 mesh. The sandblasting time is 3 seconds.

[0056] (3) Atmospheric plasma spraying of boron nitride coating on C / C composite material surface: The boron nitride used for atmospheric plasma spraying is a granulated agglomerate with a particle size of 400 mesh; the current used in atmospheric plasma spraying process is 300A; the voltage used in atmospheric plasma spraying process is 75V; the argon flow rate used in atmospheric plasma spraying process is 30L / min; the hydrogen flow rate used in atmospheric plasma spraying process is 5L / min; the distance between the spray gun and the C / C composite material is 10cm; the C / C composite material after sandblasting in step (2) is sprayed with atmospheric plasma once for 2s to obtain a C / C composite material containing boron nitride coating.

[0057] Take out the C / C composite material sample with boron nitride coating from Comparative Example 2, cover its surface with silicon powder, and then place it in a tube furnace for etching treatment at 1500℃ / 2h under an argon atmosphere to obtain the surface microstructure of the C / C composite material after silicon powder etching. Take out the C / C composite material sample with boron nitride coating from Comparative Example 2, cover its surface with silicon dioxide powder, and then place it in a tube furnace for etching treatment at 1500℃ / 2h under an argon atmosphere to obtain the surface microstructure of the C / C composite material after silicon dioxide etching.

[0058] Figure 5 Macroscopic images and cross-sectional microstructures of C / C composite materials coated with boron nitride by atmospheric plasma spraying. Figure 5 Image a shows a macroscopic image of a C / C composite material with a boron nitride coating applied by atmospheric plasma spraying. Figure 5 b is a microscopic morphology diagram of the boron nitride coating applied by atmospheric plasma spraying. Figure 5 c is the Si element distribution diagram of the C / C composite material with boron nitride coating applied by atmospheric plasma spraying after high-temperature corrosion by silicon powder. Figure 5 Figure d shows the Si element distribution of the C / C composite material with an atmospheric plasma-sprayed boron nitride coating after high-temperature corrosion by silica powder. Figure 5 As can be seen from the macroscopic photograph of a, the boron nitride coating does not form a good bond with the C / C composite substrate, and the coating flakes off when touched by hand. Figure 5 The microscopic photograph of b confirms that the sprayed coating has poor density and many microcracks. Figure 5 The microscopic images show that after high-temperature corrosion of silicon, Si elements are visible in the C / C composite substrate, indicating that the boron nitride coating with poor density and many microcracks cannot resist the corrosion of silicon. Figure 5 The microscopic photograph shows that after high-temperature corrosion of silica, the presence of Si elements in the C / C composite substrate indicates that the boron nitride coating, which has poor density and many microcracks, cannot resist the erosion of silica.

[0059] Comparative Example 3:

[0060] The silicon crystal furnace provided in this comparative example has poor resistance to silicon element corrosion. It includes a silicon crystal furnace body, the thermal structural material of which is a C / C composite material. The surface of the C / C composite material is coated with a silicon nitride coating, which is prepared on the C / C composite material in the following manner:

[0061] (1) Ultrasonic cleaning and drying of C / C composite material: The cut C / C composite material was placed in an ultrasonic cleaner and ultrasonically cleaned for 6 minutes, and then placed in an oven to dry for 10 hours.

[0062] (2) Sandblasting of C / C composite material surface: The C / C composite material from step (1) is placed in a sandblasting machine for sandblasting treatment. The sand particles used for sandblasting are silicon carbide particles with a particle size of 65 mesh. The sandblasting time is 5 seconds.

[0063] (3) Atmospheric plasma spraying of silicon nitride coating on C / C composite material surface: The silicon nitride used for atmospheric plasma spraying is granulated agglomerate with a particle size of 500 mesh; the current used in atmospheric plasma spraying process is 420A; the voltage used in atmospheric plasma spraying process is 80V; the argon flow rate used in atmospheric plasma spraying process is 40L / min; the hydrogen flow rate used in atmospheric plasma spraying process is 7L / min; the distance between the spray gun and the C / C composite material is 13cm; the C / C composite material after sandblasting in step (2) is sprayed with atmospheric plasma once for 2s to obtain a C / C composite material containing silicon nitride coating.

[0064] Take the C / C composite material sample with silicon nitride coating of Comparative Example 3, cover its surface with silicon powder, and then place it in a tube furnace for etching treatment at 1500℃ / 2h under argon atmosphere to obtain the surface microstructure of C / C composite material after silicon powder etching; take out the C / C composite material sample with silicon nitride coating of Comparative Example 3, cover its surface with silicon monoxide powder, and then place it in a tube furnace for etching treatment at 1500℃ / 2h under argon atmosphere to obtain the surface microstructure of C / C composite material after silicon monoxide etching.

[0065] Figure 6 Macroscopic images and cross-sectional microstructures of C / C composite materials coated with silicon nitride by atmospheric plasma spraying. Figure 6 Image a shows a macroscopic image of a C / C composite material with an atmospheric plasma-sprayed silicon nitride coating. Figure 6 b is a microscopic morphology diagram of the silicon nitride coating applied by atmospheric plasma spraying. Figure 6 c is the Si element distribution diagram of the C / C composite material with atmospheric plasma sprayed silicon nitride coating after high-temperature corrosion by silicon powder. Figure 6d is the Si element distribution diagram of the C / C composite material with atmospheric plasma-sprayed silicon nitride coating after high-temperature corrosion by silicon monoxide. Figure 6 As can be seen from the macroscopic photograph of a, the silicon nitride coating does not form a good bond with the C / C composite substrate, and the coating flakes off when touched by hand. Figure 6 The microscopic photograph of b confirms that the sprayed coating has poor density and many cracks. Figure 6 The microscopic photograph shows that after the silicon powder was corroded at high temperature, the Si element appeared in the C / C composite substrate, indicating that the silicon nitride coating with poor density and many microcracks could not resist the corrosion of silicon. Figure 5 The microscopic photograph shows that after high-temperature corrosion of silicon monoxide, the presence of Si elements in the C / C composite substrate indicates that the silicon nitride coating, which has poor density and many microcracks, cannot resist the erosion of silicon monoxide.

[0066] Example 1:

[0067] The silicon crystal furnace resistant to silicon element corrosion provided in this embodiment includes a silicon crystal furnace body. The thermal structural material of the silicon crystal furnace body is a C / C composite material. The surface of the C / C composite material is provided with a silicon element corrosion resistant coating made of zirconium silicate (hereinafter also referred to as zirconium silicate coating). This silicon element corrosion resistant coating is prepared on the surface of the C / C composite material by the following method (see...). Figure 4 The specific steps are as follows:

[0068] (1) Ultrasonic cleaning and drying of C / C composite materials:

[0069] The cut C / C composite material was placed in an ultrasonic cleaner and ultrasonically cleaned for 6 minutes, and then placed in an oven to dry for 9 hours.

[0070] (2) Sandblasting of C / C composite material surface:

[0071] The C / C composite material from step (1) is placed in a sandblasting machine for sandblasting. The sand used for sandblasting is silicon carbide particles with a particle size of 50 mesh. The sandblasting time is 3 seconds.

[0072] (3) Atmospheric plasma spraying of zirconium silicate coating on C / C composite material surface:

[0073] The zirconium silicate used in the preparation of atmospheric plasma spraying is a granulated agglomerate with a particle size of 400 mesh; the current used in the atmospheric plasma spraying process is 300A; the voltage used in the atmospheric plasma spraying process is 75V; the argon flow rate is 30L / min; the hydrogen flow rate is 5L / min; the distance between the spray gun and the C / C composite material is 10cm; the C / C composite material after sandblasting in step (2) is subjected to atmospheric plasma spraying once for 2s to obtain a C / C composite material containing a zirconium silicate coating.

[0074] Figure 7 Cross-sectional microstructure and Zr elemental energy spectrum of C / C composite material with atmospheric plasma spraying of zirconium silicate coating. Figure 7 a. Cross-sectional microstructure of C / C composite material with zirconium silicate coating applied by atmospheric plasma spraying. Figure 7 b is the cross-sectional microscopic Zr element energy spectrum of the C / C composite material with atmospheric plasma spraying of zirconium silicate coating. As can be seen from the figure, the zirconium silicate coating on the surface of the C / C composite material with atmospheric plasma spraying of zirconium silicate coating is continuous, uniform and dense, with a maximum coating thickness of up to 49.2 μm, and the spraying effect is good.

[0075] Three sets of C / C composite material samples with zirconium silicate coatings from Example 1 were taken out, and their surfaces were covered with silicon powder, silicon dioxide powder, and silicon monoxide powder, respectively. They were then placed in tube furnaces and subjected to etching treatment at 1500℃ for 2 hours under an argon atmosphere to obtain the surface microstructure of the C / C composite material after etching with silicon powder, silicon dioxide powder, and silicon monoxide powder, respectively.

[0076] Figure 8 Microscopic morphology of the cross-section of C / C composite material with zirconium silicate coating applied by atmospheric plasma spraying, and energy dispersive spectroscopy (EDS) of the cross-section of Si. Figure 8 Image a shows the cross-sectional microstructure of the C / C composite material with an atmospheric plasma-sprayed zirconium silicate coating, corroded by silicon powder. Figure 8 b is the cross-sectional energy spectrum of Si element in the C / C composite material with zirconium silicate coating applied by atmospheric plasma spraying, which is corroded by silicon powder. As can be seen from the figure, the surface of the C / C composite material is protected by the zirconium silicate coating. No obvious silicon element was found in the C / C composite material matrix, so the coating was not penetrated. After the silicon powder melts, it is difficult to contact the C / C composite material matrix. Therefore, the zirconium silicate coating has good resistance to silicon corrosion.

[0077] Figure 10 Microscopic morphology of the cross-section of a C / C composite material with an atmospheric plasma-sprayed zirconium silicate coating, corroded by silica powder, and energy dispersive spectroscopy (EDS) of the cross-section containing Si. Figure 10 Image a shows the cross-sectional microstructure of the C / C composite material with an atmospheric plasma-sprayed zirconium silicate coating corroded by silica powder. Figure 10 b is the cross-sectional energy spectrum of Si element in the C / C composite material with atmospheric plasma sprayed zirconium silicate coating corroded by silica powder. As can be seen from the figure, the C / C composite matrix is ​​protected by the zirconium silicate coating. There is a small amount of residual silica above the coating, and the coating is not penetrated. After the silica powder melts and volatilizes, it is difficult to contact the C / C composite matrix. Therefore, the zirconium silicate coating has good resistance to silica corrosion.

[0078] Figure 12Microscopic morphology of the cross-section of a C / C composite material with an atmospheric plasma-sprayed zirconium silicate coating, corroded by silica powder, and energy dispersive spectroscopy (EDS) of the cross-section containing Si. Figure 12 Image a shows the cross-sectional microstructure of a C / C composite material with an atmospheric plasma-sprayed zirconium silicate coating, corroded by silica powder. Figure 12 b is the cross-sectional energy spectrum of Si elements in the C / C composite material with an atmospheric plasma-sprayed zirconium silicate coating, which is corroded by silica powder. As can be seen from the figure, the surface of the C / C composite material is protected by the zirconium silicate coating. There is no large amount of silicon element in the C / C composite material matrix, so the coating is not penetrated. After the silica powder melts and volatilizes, some of it reacts with the zirconium silicate coating, but does not penetrate into the C / C composite material matrix. Therefore, the zirconium silicate coating has good resistance to silica corrosion.

[0079] Example 2:

[0080] The silicon crystal furnace resistant to silicon element corrosion provided in this embodiment has the same structure as that in Embodiment 1. The difference lies in the different preparation process parameters of the silicon element corrosion resistant coating on the C / C composite material surface, as detailed below:

[0081] (1) Ultrasonic cleaning and drying of C / C composite material: The cut C / C composite material was placed in an ultrasonic cleaner and ultrasonically cleaned for 18 minutes, and then placed in an oven to dry for 18 hours.

[0082] (2) Sandblasting of C / C composite material surface: The C / C composite material from step (1) is placed in a sandblasting machine for sandblasting treatment. The sand particles used for sandblasting are silicon carbide particles with a particle size of 78 mesh. The sandblasting time is 6 seconds.

[0083] (3) Atmospheric plasma spraying of zirconium silicate coating on C / C composite material surface: The zirconium silicate used for atmospheric plasma spraying is a granulated agglomerate with a granulation size of 550 mesh; During the atmospheric plasma spraying process, the current used is 410A, the voltage used is 79V, the argon flow rate is 38L / min, the hydrogen flow rate is 8L / min, and the distance between the spray gun and the C / C composite material is 12cm; The C / C composite material after sandblasting in step (2) is subjected to atmospheric plasma spraying once for 2s to obtain a C / C composite material containing zirconium silicate coating.

[0084] Figure 9 Cross-sectional microstructure and Zr elemental energy spectrum of C / C composite material with atmospheric plasma spraying of zirconium silicate coating. Figure 9 a is a cross-sectional microstructure of the C / C composite material with an atmospheric plasma-sprayed zirconium silicate coating. Figure 9b is the cross-sectional microscopic Zr element energy spectrum of the C / C composite material with atmospheric plasma spraying of zirconium silicate coating. As can be seen from the figure, the zirconium silicate coating on the surface of the C / C composite material with atmospheric plasma spraying of zirconium silicate coating is continuous, uniform and dense, and the spraying effect is good.

[0085] Referring to Example 1, corrosion tests were conducted on the surface of the C / C composite material with zirconium silicate coating obtained in Example 2 using silicon powder, silicon dioxide powder, and silicon monoxide powder, respectively. The test results were the same as those in Example 1, showing excellent resistance to corrosion by silicon, silicon monoxide, and silicon dioxide.

[0086] Example 3:

[0087] The silicon crystal furnace resistant to silicon element corrosion provided in this embodiment has the same structure as that in Embodiment 1. The difference lies in the different preparation process parameters of the silicon element corrosion resistant coating on the C / C composite material surface, as detailed below:

[0088] (1) Ultrasonic cleaning and drying of C / C composite material: The cut C / C composite material was placed in an ultrasonic cleaner and ultrasonically cleaned for 15 minutes, and then placed in an oven to dry for 16 hours.

[0089] (2) Sandblasting of C / C composite material surface: The C / C composite material from step (1) is placed in a sandblasting machine for sandblasting treatment. The sand particles used for sandblasting are silicon carbide particles with a particle size of 75 mesh. The sandblasting time is 7s.

[0090] (3) Atmospheric plasma spraying of zirconium silicate coating on C / C composite material surface: The zirconium silicate used for atmospheric plasma spraying is a granulated agglomerate with a granulation size of 580 mesh; During the atmospheric plasma spraying process, the current used is 360A, the voltage used is 85V, the argon flow rate is 40L / min, the hydrogen flow rate is 6L / min, and the distance between the spray gun and the C / C composite material is 11cm; The C / C composite material after sandblasting in step (2) is subjected to atmospheric plasma spraying once for 2s to obtain a C / C composite material containing zirconium silicate coating.

[0091] Figure 11 Cross-sectional microstructure and Zr elemental energy spectrum of C / C composite material with atmospheric plasma spraying of zirconium silicate coating. Figure 11 a is a cross-sectional microstructure of the C / C composite material with an atmospheric plasma-sprayed zirconium silicate coating. Figure 11 b is the cross-sectional microscopic Zr element energy spectrum of the C / C composite material with four zirconium silicate coatings applied by atmospheric plasma spraying. As can be seen from the figure, the zirconium silicate coating on the surface of the C / C composite material with the zirconium silicate coating applied by atmospheric plasma spraying is continuous, uniform and dense, and the spraying effect is good.

[0092] Referring to Example 1, corrosion tests were conducted on the surface of the C / C composite material with zirconium silicate coating obtained in Example 3 using silicon powder, silica powder, and silica powder, respectively. The test results were the same as those in Example 1, showing excellent resistance to corrosion by silicon, silica, and silica.

[0093] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.

Claims

1. A silicon crystal furnace resistant to silicon corrosion, comprising a silicon crystal furnace body, wherein the thermal structural material of the silicon crystal furnace body is a C / C composite material, characterized in that, The surface of the C / C composite material is coated with a silicon-resistant coating made of zirconium silicate. This silicon-resistant coating is prepared on the surface of the C / C composite material by the following method: The C / C composite material is placed in a sandblasting machine, and any one of the following abrasive particles—silicon carbide particles, alumina particles, or quartz sand—is selected to sandblast the surface of the C / C composite material. Then, zirconium silicate with a particle size of 400-600 mesh is selected as the agglomerate and atmospheric plasma spraying is applied to the surface of the C / C composite material to form a continuous, uniform, and dense silicon-resistant coating that can simultaneously resist corrosion by elemental silicon (Si), silicon monoxide (SiO), and silicon dioxide (SiO2). The particle size of the sand used for sandblasting is 50-80 mesh; the sandblasting time is 3-8 seconds. In the atmospheric plasma spraying process, the current used is 300A~450A, the voltage used is 75V~90V, the argon flow rate is 30L / min~45L / min, the hydrogen flow rate is 5L / min~8L / min, and the distance between the spray gun and the C / C composite material is 10cm~15cm. The atmospheric plasma spraying was applied once, with a spraying time of 2 seconds.

2. The silicon crystal furnace resistant to silicon element corrosion according to claim 1, characterized in that, The thickness of the silicon-resistant coating is 10-100 μm.

3. The silicon crystal furnace resistant to silicon element corrosion according to claim 1, characterized in that, The density of the C / C composite material is 1.4 g / cm³. 3 ~1.6g / cm 3 .

4. The silicon crystal furnace resistant to silicon element corrosion according to claim 1, characterized in that, Before feeding the C / C composite material into the sandblasting machine, the following steps are also included: The cut C / C composite material is placed in an ultrasonic cleaner for ultrasonic cleaning, and then placed in an oven for drying.

5. The silicon crystal furnace resistant to silicon element corrosion according to claim 4, characterized in that, The ultrasonic cleaning reagent is any one of alcohol, acetone, or water; the ultrasonic cleaning time is 5 to 20 minutes; and the drying time in the oven is 6 to 18 hours.

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