Polycrystalline silicon hydrogenation system protective coating and preparation method and spraying device thereof

Abstract

The invention discloses a protective coating of a polycrystalline silicon hydrogenation system as well as a preparation method and a spraying device of the protective coating, and belongs to the technical field of polycrystalline silicon production. The protective coating comprises an inhibition layer, an abrasion layer and a sealing layer, the abrasion layer is arranged between the inhibition layer and the sealing layer, and the inhibition layer is in contact with a protected surface of the hydrogenation system; the inhibition layer comprises the following components in percentage by mass: 15 to 19 percent of Cr, 20 to 24 percent of Co, 11.5 to 13.5 percent of Al, 0.55 to 0.75 percent of Y, 0.18 to 0.23 percent of Hf, 0.32 to 0.45 percent of Si and the balance of Ni; the abrasion layer is prepared from, by mass, 8%-12% of Co, 3%-8% of Cr, 0.6%-1.3% of RE and the balance WC, and RE is rare earth oxide and comprises one or more of CeO2, La2O3 and Er2O3; and the sealing layer comprises the following components in percentage by mass: 25-35% of Si, 2-6% of polybenzoate and the balance of Al. By optimizing the components of the protective coating, combining with a proper preparation method and using a corresponding spraying device, the protective coating which is high in abrasion resistance and good in binding force with a protected surface is obtained, the service life of a hydrogenation system is prolonged, and the product quality is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polysilicon production, and relates to a polysilicon hydrogenation system protective coating and a preparation method and a spraying device thereof. Background Art

[0002] Under the strategic goal of "dual carbon" and the general trend of energy transformation and upgrading, photovoltaic power generation is the most core technology and an emerging industry that is being developed with emphasis. As an indispensable basic material for manufacturing photovoltaic panels, high-purity polysilicon materials have also ushered in new development opportunities. SiHCl3 is the raw material for producing polysilicon by the modified Siemens method. It is mainly produced by adding silicon powder, H2, and SiCl4 to the hydrogenation furnace at a temperature of 600℃~800℃ and a pressure of 2~4MPa through the hydrogenation system. The reaction generates SiHCl3 and HCl byproducts. During the reaction, some unreacted silicon powder and impurities will be produced. In order to improve the recovery rate of silicon powder and reduce the content of impurities in the product, a cyclone separator is provided in the hydrogenation furnace. When chlorosilane and silicon powder are continuously fluidized in the hydrogenation furnace, silicon particles and HCl will cause the inner wall of the hydrogenation furnace and the cyclone separator to be abraded and peeled off, accelerating the damage of the equipment and increasing the frequency of equipment maintenance and replacement. At the same time, the impurities produced by the wear of the inner wall are likely to increase the impurity content of the product.

[0003] Protective coatings have become a promising solution to extend the service life of hydrogenation system equipment components. At present, protective coatings are usually layered structures, including an adhesive layer and a corrosion-resistant layer. Generally, the adhesive layer and the corrosion-resistant layer are sprayed onto the inner wall of the hydrogenation furnace and the cyclone separator in sequence by spraying to protect the hydrogenation furnace and the cyclone separator. However, during the use of the hydrogenation furnace, the Fe, B, P and other elements contained in the inner wall and the cyclone separator will diffuse outward and enter the reaction chamber of the hydrogenation furnace, resulting in an increase in the SiHCl3 impurity content, affecting the quality of polysilicon production. At the same time, the existing spraying method has a significant negative impact on the corrosion resistance of the protective coating, resulting in a decrease in the corrosion resistance of the protective coating and an inability to fully exert the protective effect.

[0004] Therefore, it is necessary to provide a protective coating for a polysilicon hydrogenation system, a preparation method and a spraying device thereof. By optimizing the composition of the protective coating, coordinating a reasonable protective coating preparation method, and using a suitable device to spray the protective coating, the corrosion resistance of the protective coating and the bonding performance between the protective coating and the protected surface can be improved, while facilitating spraying. Summary of the invention

[0005] In order to overcome the problems in the background technology, the present invention optimizes the coating formula to hinder the external diffusion elements of the hydrogenation furnace and the cyclone separator, reduce the influence of the external diffusion elements on the protective coating, improve the bonding performance between the protective coating and the hydrogenation furnace or the cyclone separator, and at the same time improve the corrosion resistance and other properties of the protective coating itself, so that the protective coating can provide long-term and efficient protection for the hydrogenation system.

[0006] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0007] In one aspect, the present invention provides a protective coating for a polysilicon hydrogenation system, the protective coating comprising an inhibition layer, an abrasive layer, and a sealing layer, wherein the inhibition layer and the sealing layer are provided with an abrasive layer, and the inhibition layer is in contact with a protected surface of the hydrogenation system;

[0008] The inhibiting layer comprises, by mass fraction, Cr: 15-19%, Co: 20-24%, Al: 11.5-13.5%, Y: 0.55-0.75%, Hf: 0.18-0.23%, Si: 0.32-0.45%, and the balance is Ni;

[0009] The components of the abrasive layer include, by mass fraction, 8-12% Co, 3-8% Cr, 0.6-1.3% RE, and the balance is WC, wherein the RE is a rare earth oxide, including one or more of CeO2, La2O3, and Er2O3;

[0010] The sealing layer comprises, by mass fraction, 25-35% Si, 2-6% polyphenylene ester, and the remainder Al.

[0011] Preferably, the inhibition layer has a thickness of 40 to 90 μm, the abrasion layer has a thickness of 80 to 300 μm, and the sealing layer has a thickness of 10 to 30 μm.

[0012] Another aspect of the present invention provides a method for preparing a protective coating of a polysilicon hydrogenation system, the preparation method comprising the following steps:

[0013] (1) After respectively mixing the raw material powders of the inhibition layer, the abrasion layer, and the sealing layer, the inhibition layer spray composite powder, the abrasion layer spray composite powder, and the sealing layer spray composite powder are obtained, and the inhibition layer spray composite powder and the abrasion layer spray composite powder are respectively dissolved in deionized water, and a dispersant and a pH adjuster are added to adjust the pH of the liquid to 8-9, and then the liquid is ground, and then the liquid is passed through a 300-325 mesh sieve to prepare an inhibition layer liquid phase material and an abrasion layer liquid phase material;

[0014] (2) In an argon atmosphere, the liquid phase material of the inhibition layer and the liquid phase material of the abrasion layer are sprayed on the protected surface of the hydrogenation system in sequence by using a liquid phase supersonic flame spraying technique to form an inhibition layer and an abrasion layer;

[0015] (3) Within 30 seconds after the abrasive layer is sprayed, the sealing layer spray composite powder is sprayed onto the abrasive layer by cold spraying technology. During the spraying process, the sealing layer is simultaneously ground and polished. After grinding and polishing, the roughness is ≤0.1μm.

[0016] Preferably, in step (1), the dispersant is ammonium polyacrylate, the pH adjuster is an aqueous ammonia suspension, the solid content of the composite powder in the inhibition layer liquid phase material and the abrasion layer liquid phase material is 20-32wt%, and the mass of the added dispersant is 0.5% of the mass of the composite powder.

[0017] Preferably, the mixing process of the abrasive layer raw material powder specifically comprises the following steps:

[0018] S1: ball milling WC, Co and Cr powders to obtain mixed powders, wherein the ball milling method is dry milling, the ball-to-material ratio is 2.5:1, the rotation speed is 300 r / min, and the dry milling time is 8 h;

[0019] S2: Add the mixed powder obtained in the step S1 and the RE powder into deionized water, and add polyvinyl alcohol, a dispersant, and a defoamer to make a slurry, and then continue to ball-mill the slurry for 1 hour. In the slurry, the solid content is 50wt%, the amount of polyvinyl alcohol added is 1.5-2.5% of the mass of the mixed powder, the amount of dispersant added is 0.1% of the mass of the mixed powder, and the amount of defoamer added is 0.1% of the mass of the mixed powder. The dispersant is polyethylene glycol, and the defoamer is tributyl phosphate.

[0020] S3: spraying the slurry obtained by ball milling in step S2 to obtain spray powder, wherein the air inlet temperature is 235-255°C, the air outlet temperature is 95-105°C, the spray pressure is 0.05 kPa, the peristaltic pump opening is 26%, and the atomizer speed is 25000 rpm;

[0021] S4: In an argon atmosphere, heat-treating the spraying powder obtained in step S3, and then sifting out the powder using a 300-325 mesh sieve, i.e., the abrasive layer spraying composite powder.

[0022] Preferably, in step S4, the heat treatment temperature is 1000-1200° C., and the heat treatment time is 2-2.5 h.

[0023] Preferably, in step (1), the particle size of the composite powder sprayed on the inhibition layer is 100-500 nm, the particle size of the composite powder sprayed on the abrasive layer is 13-20 mm, the particle size of the composite powder sprayed on the sealing layer is 35-45 μm, and the grinding time is 1-2 h.

[0024] Preferably, in the step (2), the amount of kerosene in the supersonic flame spraying process is 27 LPH, the amount of oxygen is 800 NLPM, the liquid phase material delivery rate is 30-40 mL / min, the spraying distance is 340 mm, the spray gun moving speed is 10 mm / s, and the spraying direction of the spray gun is perpendicular to the protected surface.

[0025] Preferably, in step (3), the working gas and powder feeding gas in the cold spraying process are both nitrogen, the spraying distance is 250 mm, the spraying pressure is 1.5 MPa, and the spraying direction of the spray gun is perpendicular to the protected surface.

[0026] The present invention also proposes a spraying device for the above-mentioned preparation method, wherein the spraying device comprises a hydrogenation furnace inner wall spraying device and a cyclone separator spraying device.

[0027] The hydrogenation furnace inner wall spraying and polishing device comprises a cross-shaped track 1, a first guide member 2, a cold spray gun 3, a hot spray gun 4, an argon gas delivery pump 5, a hydrogenation furnace fixed frame 6, a rotating drive member 7, a bottom cover, a support frame, a second guide member 15, a telescopic rod 16, and a polishing grease 17. The hydrogenation furnace fixed frame 6 is fixedly sleeved on the outer shell of the hydrogenation furnace body 8. The hydrogenation furnace body 8 is horizontally arranged, and the axis of the hydrogenation furnace body 8 is horizontal. The hydrogenation furnace fixed frame 6 is rotatably installed on the support frame. The transmission part of the rotating drive member 7 is fixedly connected to the hydrogenation furnace fixed frame 6. The rotating drive member 7 drives the hydrogenation furnace fixed frame 6 to rotate along the axis of the hydrogenation furnace body 8. The bottom cover is covered with the bottom of the hydrogenation furnace body 8. A sealing gasket 9 is arranged at the covering position of the bottom cover and the bottom of the hydrogenation furnace body 8. The cross-shaped track 1 is located inside the hydrogenation furnace body 8, and one end of the cross-shaped track 1 passes through the bottom cover and extends to the outside of the hydrogenation furnace body 8 for fixing. The first guide member 2 slides along the cross-shaped track 1. The cold spray gun 3 and the hot spray gun 4 are arranged in a cross shape and installed on the first guide member 2. The first guide member 2 controls the cold spray gun 3 and the hot spray gun 4 to rotate and move. The argon gas delivery pump 5 delivers argon gas to the inside of the hydrogenation furnace body 8 through a pipeline that passes through the bottom cover and extends to the inside of the hydrogenation furnace body 8. The bottom cover is provided with an argon gas outlet 10. The second guide member 15 slides along the cross-shaped track 1. The end of the fixed section of the telescopic rod 16 is installed on the second guide member 15. The polishing grease 17 is fixedly arranged at the end of the telescopic section of the telescopic rod 16.

[0028] The cyclone separator spraying device includes a first guide member 2, a cold spray gun 3, a hot spray gun 4, an argon delivery pump 5, a box 11, a motor 12, a slide rail 13, a second guide member 15, a telescopic rod 16, and a polishing grease 17. The slide rail 13 is located inside the box 11 and is installed on the bottom surface of the box 11. The first guide member 2 slides along the slide rail 13. The cold spray gun 3 and the hot spray gun 4 are arranged in a cross shape and are installed on the first guide member 2. The first guide member 2 controls the cold spray gun 3 and the hot spray gun 4 to rotate and move. The argon delivery pump 5 passes through the box 11. 1 and a pipeline extending to the inside of the box body 11 transports argon gas into the box body 11. The side wall of the box body 11 is provided with an argon gas outlet 10. The cyclone separator body 14 is horizontally installed in the box body 11 through a motor 12. The motor 12 drives the cyclone separator body 14 to rotate around its axis. The cold spray gun 3 and the hot spray gun 4 spray materials toward the cyclone separator body 14. The second guide member 15 slides along the slide rail 13. The fixed section end of the telescopic rod 16 is installed on the second guide member 15. The polishing grease 17 is fixedly arranged at the telescopic section end of the telescopic rod 16.

[0029] Beneficial effects of the present invention:

[0030] 1. After the protective coating of the present invention is sprayed, the difference in thermal expansion coefficient between the inhibition layer and the inner wall of the hydrogenation furnace or the cyclone separator is small, and the bonding performance is good. At the same time, when Fe, B, P, etc. in the inner wall of the hydrogenation furnace or the cyclone separator diffuse outward, they react with Ni, Cr, Si in the inhibition layer to generate NiCr 15 Fe4B3Si4,NiCr 15 Fe4B3Si4 is a hard and dense self-fluxing alloy with good corrosion resistance and oxidation resistance. The inhibition layer prevents the outward diffusion of elements, reduces the SiHCl3 impurity content, and further enhances the corrosion resistance and oxidation resistance of the inhibition layer itself.

[0031] 2. The present invention uses cold spraying technology to spray the sealing layer, which avoids the oxidation of Al and Si and the melting and volatilization of PHE, fills the pores generated by thermal spraying, and is beneficial to improving the corrosion resistance of the protective coating.

[0032] 3. The present invention heat treats the abrasive layer raw material so that the WC particles and the Co and Cr bonding phases are bonded through chemical reactions and interface atomic diffusion, thereby promoting the alloying of the WC particles with Co and Cr and the dissolution of Cr in WC, improving the uniformity of the distribution of W, Co and Cr in the thermal spraying particles and the protective coating, avoiding the segregation of the bonding phase, reducing the decarburization of WC and the formation of W2C, and reducing the potential difference between WC and the Co and Cr bonding phases and the driving force of microgalvanic corrosion, thereby making the WCCoCr coating exhibit higher wear resistance.

[0033] 4. During the service life of the coating of the present invention, silicon powder contacts the coating surface and combines to form a wear-resistant reinforcing phase of mullite (Al2O3-SiO2), further enhancing the high-temperature abrasion resistance of the protective coating.

[0034] 5. The present invention uses liquid phase material as the thermal spraying raw material and liquid as the transportation medium of the powder. The feeding is not limited by the powder size and the nano-scale powder can be directly fed and sprayed. At the same time, since the liquid phase solvent evaporates and takes away a large amount of heat during the spraying process, the growth and crystal transformation of the sprayed powder grains due to heat can be avoided, the grain boundary area is reduced, and the probability of dislocation is reduced, thereby reducing defects such as voids and inclusions inside the grains, reducing the degree of destruction of intercrystalline continuity, and is beneficial to improving the wear resistance of the protective coating.

[0035] 6. The present invention performs grinding and polishing while spraying the protective coating, so that the protective coating maintains a high degree of smoothness, enhances the reflectivity of the protective coating, reduces the heat loss of the reaction in the hydrogenation furnace, and is beneficial to reducing the energy consumption of polysilicon production.

[0036] 7. During the spraying process of the present invention, the hydrogenation furnace is horizontally arranged with a lower center of gravity, which effectively reduces the probability of device shaking, helps to improve the spraying quality, and has higher safety.

[0037] 8. In the internal spraying device of the hydrogenation furnace of the present invention, the guide member slides along the cross-shaped track, and at the same time, the guide member controls the cold spray gun and the hot spray gun to rotate, so that when the spray gun sprays at different positions, the spray gun remains vertical to the sprayed surface, and the spraying distance remains consistent, which is convenient for controlling the spray gun.

[0038] 9. In the present invention, by adding RE to the raw material of the abrasive layer, RE can act as a catalyst for grain refinement and coating self-repair, making the grains of the protective coating more uniform and finer. This fine microstructure can reduce the crack propagation path and enable the protective coating to recover from slight damage, thereby enhancing the corrosion resistance and protection time of the protective coating. At the same time, the fine microstructure can also enhance the hardness of the protective coating, improve the toughness of the coating, and enable the protective coating to more effectively withstand the impact of silicon particles. The addition of RE can improve the oxidation resistance of the coating, which helps the protective coating maintain its integrity in a high temperature and high pressure environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is the surface morphology of the protective coating of the present invention after friction and wear experiment.

[0040] Figure 2 This is the three-dimensional profile of the wear scar after the friction and wear test of the protective coating of the present invention.

[0041] Figure 3 This is the friction coefficient variation curve of the protective coating of the present invention.

[0042] Figure 4 This is a surface morphology diagram of the protective coating of the present invention after HCl corrosion.

[0043] Figure 5 It is a schematic diagram of the structure of the internal spraying device of the hydrogenation furnace of the present invention.

[0044] Figure 6 It is a schematic diagram of the structure of the cyclone separator spraying device of the present invention.

[0045] Figure 7 Schematic diagram of the structure of grinding and polishing parts.

[0046] In the figure, 1-cross track, 2-first guide, 3-cold spray gun, 4-hot spray gun, 5-argon delivery pump, 6-hydrogenation furnace fixing frame, 7-rotation driving member, 8-hydrogenation furnace body, 9-sealing gasket, 10-argon outlet, 11-box, 12-motor, 13-slide rail, 14-cyclone separator body, 15-second guide, 16-telescopic rod, 17-polishing grease. DETAILED DESCRIPTION

[0047] The present invention is further described in detail below in conjunction with specific embodiments.

[0048] In the embodiments and comparative examples of the present invention, chemical reagents not otherwise specified were all commercially available analytically pure reagents for experiments.

[0049] The spraying device of the present invention was used to spray the protective coating of the embodiment and the comparative example.

[0050] The composition of the protective coating in Examples 1-3 of the present invention is shown in Table 1.

[0051] Table 1

[0052]

[0053]

[0054] Example 1

[0055] In this embodiment, the protective coating is sprayed according to the following steps:

[0056] (1) Weigh the corresponding raw material powders according to the components of the protective coating in Table 1, and mix the raw material powders of the inhibition layer, the abrasion layer, and the sealing layer respectively to obtain the inhibition layer spray composite powder, the abrasion layer spray composite powder, and the sealing layer spray composite powder, wherein the inhibition layer and the sealing layer raw material powders are mixed by a mixer or the like.

[0057] The abrasive layer raw material powder is treated by the following method to obtain the abrasive layer spray composite powder: the abrasive layer raw material powder is added to a planetary ball mill, the planetary ball mill speed is set to 300r / min, the abrasive layer raw material powder is ball milled for 8h under the condition of a ball-to-material ratio of 2.5:1, and then RE powder and deionized water are added to the planetary ball mill, and polyvinyl alcohol, dispersant and defoamer are added at the same time, and the ball milling is continued for 1h, and the polyvinyl alcohol content in the obtained slurry is 1.5%, the dispersant and defoamer content are both 0.1%, and the solid content is 50wt%. Then the slurry is added to a centrifugal spray dryer, the centrifugal spray dryer inlet temperature is set to 235℃, the outlet temperature is set to 95℃, the centrifugal spray dryer tower pressure is set to 0.05kPa, the peristaltic pump opening is set to 26%, the atomizer speed is set to 25000rpm, the centrifugal spray dryer is turned on, the centrifugal spray dryer is sprayed and powdered, and the powder produced by the centrifugal spray dryer is collected, that is, WCCoCr-RE mixed powder. Then the WCCoCr-RE mixed powder is put into a tubular furnace, the heating temperature of the tubular furnace is set to 1000°C, and argon is filled into the tubular furnace to form an argon atmosphere environment in the tubular furnace. After the WCCoCr-RE mixed powder is heated in the tubular furnace for 2.5 hours, the WCCoCr-RE mixed powder is taken out, and the mixed powder is sieved through a 300-325 mesh sieve. The sieved mixed powder is the abrasive layer spray composite powder.

[0058] The inhibition layer spray composite powder and the abrasion layer spray composite powder are added into deionized water to prepare a solution with a solid content of 20wt%, and polyacrylamide and ammonia suspension are added at the same time. After the pH value of the solution is adjusted to 8-9, the solution is ground for 1 hour using a rod-type sand mill, and then the product is sieved through a 300-325 mesh sieve for use. At this time, the inhibition layer and the abrasion layer are both stored in the form of liquid phase materials for use, and the sealing layer spray composite powder is directly stored in the form of powder for use.

[0059] (2) Add the liquid phase material of the inhibition layer and the liquid phase material of the wear layer into the two feed tanks of the supersonic flame spraying equipment respectively, set the kerosene volume of the supersonic flame spraying to 27LPH, the oxygen volume to 800NLPM, and set the liquid phase material delivery volume to 30mL / min. Figure 5-6As shown, the first guide member 2 and the second guide member 15 are electric drive components, which can be controlled to move on the cross-shaped track 1 or the slide rail 13 by the control system (PLC system), and their moving speed can be set by the control system. The telescopic rod 16 is an electro-hydraulic push rod or an electric push rod, which can be controlled to extend and retract by the control system. At the same time, the first guide member 2 can be controlled by the control system to drive the cold spray gun 3 and the thermal spray gun 4 to rotate. After the spraying parameters of the supersonic flame spraying equipment are set, the first guide member 2 is controlled by the control system to move to the spraying starting position on the cross-shaped track 1, and the moving speed of the first guide member 2 is preset to 10mm / s, and then the first guide member 2 is controlled by the control system to drive the thermal spray gun 4 to rotate, so that the spraying direction of the thermal spray gun 4 is perpendicular to the surface to be sprayed. The bottom cover is closed with the hydrogenation furnace body 8, the argon delivery pump 5 is turned on, and argon is filled into the hydrogenation furnace body 8. The rotary drive member 7 is turned on (the rotary drive member can use a motor or other equipment, and the rotary drive member 7 is fixedly installed on a fixed surface such as a wall). The rotary drive member 7 drives the hydrogenation furnace fixed frame 6 to rotate, and the hydrogenation furnace fixed frame 6 drives the hydrogenation furnace body 8 to rotate. At this time, the supersonic flame spraying equipment is turned on, and the feeding tank of the inhibition layer liquid phase material is turned on to feed the liquid phase material to the thermal spray gun 4. The thermal spray gun 4 sprays the liquid phase material onto the inner wall of the hydrogenation furnace body 8. As the hydrogenation furnace body 8 rotates, the liquid phase material sprayed by the thermal spray gun 4 can form a ring on the inside of the hydrogenation furnace body 8, thereby completing a circle of inhibition layer spraying. After completing one circle, the staff controls the guide member 2 to move on the cross track 1, drives the thermal spray gun 4 to move, and performs the next circle of inhibition layer spraying. When it is necessary to change the spraying distance between the cold spray gun 3 or the hot spray gun 4 and the inner wall of the hydrogenation furnace body 8, the guide member 2 can also be controlled to move in the vertical section of the cross-shaped track 1. During normal spraying, since the spray direction of the spray gun is perpendicular to the spraying surface and the distance is fixed, during normal spraying, the guide member 2 is generally not controlled to move in the vertical section of the cross-shaped track 1. Only when there are special circumstances and the spraying angle or spraying distance needs to be changed, the guide member 2 is controlled to slide to the vertical section of the cross-shaped track 1. After the inhibition layer is sprayed, the feed tank of the liquid phase material of the inhibition layer is closed to transport the liquid phase material to the thermal spray gun 4, and the feed tank of the liquid phase material of the abrasion layer is opened to transport the liquid phase material to the thermal spray gun 4. The abrasion layer spraying can be completed by controlling the guide member 2 and the thermal spray gun 4 using the same control method as the inhibition layer spraying.

[0060] (3) After the abrasive layer is sprayed, close the feed tank of the abrasive layer liquid material to feed the liquid material to the thermal spray gun 4, and at the same time close the supersonic flame spraying equipment. Release the movement speed limit of the first guide member 2, control the first guide member 2 to move quickly to the spraying starting point, and control the first guide member 2 and the cold spray gun 3 in the same way. Adjust the spraying direction of the cold spray gun 3 to be perpendicular to the inner wall of the hydrogenation furnace body 8, and set the spraying pressure of the cold spray equipment (PCS-1000 cold spray system) to 1.5MPa. After the parameters of the cold spray gun 3 and the spraying equipment are set, control the second guide member 15 to move to the polishing starting point through the control system, and then control The telescopic rod 16 is extended until the polishing grease 17 contacts the inner wall of the hydrogenation furnace body 8, and the cold spraying equipment is turned on to spray the sealing layer. During the spraying process, the second guide 15 is controlled to move in the direction of the first guide 2. After the cold spray gun 3 completes a circle of sealing layer spraying, the second guide 15 drives the telescopic rod 16 and the polishing grease 17 to move to the position of the previously sprayed circle of sealing layer, and the sealing layer is polished. The polishing grease 17 only needs to polish the sealing layer sprayed on the side wall of the hydrogenation furnace body 8. After the spraying is completed, the grinding and polishing are also completed, the rotary drive 7 is turned off, the cold spraying equipment is turned off, the argon delivery pump 5 is turned off, and a protective coating is formed on the inner wall of the hydrogenation furnace body 8.

[0061] During the spraying process, the argon delivery pump 5 remains turned on and continuously inputs argon into the hydrogenation furnace body 8. When the input argon is excessive, the argon is discharged from the argon outlet 10 to keep the argon flowing in the hydrogenation furnace body 8. On the one hand, an argon atmosphere environment can be formed in the hydrogenation furnace body 8 to protect the spray powder from being oxidized during the spraying process. On the other hand, it can take away the undeposited particle powder and steam generated during the spraying process, keep the spraying environment clean, and prevent dust from affecting the spray gun and coating.

[0062] For the spraying process of the cyclone separator body 14 and the spraying process of the hydrogenation furnace body 8, the control method of the first guide member 2, the cold spray gun 3, the hot spray gun 4, the second guide member 15 and the telescopic rod 16 is the same, and the spraying process is also the same. Only during the spraying process, the cyclone separator body 14 is driven to rotate by turning on the motor 12.

[0063] The spraying distances of the cold spray gun 3 and the hot spray gun 4 can be controlled by selecting spray guns of different lengths.

[0064] The porosity of the protective coating after spraying is ≤0.1%, the friction coefficient is ≤0.35, the hardness is ≥760HV0.3, and the wear rate is ≤2x10 -16 m 3 / (N·m), corrosion rate in 36% HCl solution ≤0.01mm / a.

[0065] Example 2

[0066] In this embodiment, the protective coating is sprayed according to the following steps:

[0067] (1) Weigh the corresponding raw material powders according to the components of the protective coating in Table 1, and mix the raw material powders of the inhibition layer, the abrasion layer, and the sealing layer respectively to obtain the inhibition layer spray composite powder, the abrasion layer spray composite powder, and the sealing layer spray composite powder, wherein the inhibition layer and the sealing layer raw material powders are mixed by a mixer or the like.

[0068] The abrasive layer raw material powder is treated by the following method to obtain the abrasive layer spray composite powder: the abrasive layer raw material powder is added to a planetary ball mill, the planetary ball mill speed is set to 300r / min, the abrasive layer raw material powder is ball milled for 8h under the condition of a ball-to-material ratio of 2.5:1, then RE powder and deionized water are added to the planetary ball mill, polyvinyl alcohol, dispersant, and defoamer are added, and the ball milling is continued for 1h, and the polyvinyl alcohol content in the obtained slurry is 2.5%, the dispersant and defoamer content are both 0.1%, and the solid content is 50wt%. Then the slurry is added to a centrifugal spray dryer, the centrifugal spray dryer inlet temperature is set to 255℃, the outlet temperature is set to 105℃, the centrifugal spray dryer tower pressure is set to 0.05kPa, the peristaltic pump opening is set to 26%, the atomizer speed is set to 25000rpm, the centrifugal spray dryer is turned on, the centrifugal spray dryer is sprayed and powdered, and the powder produced by the centrifugal spray dryer is collected, that is, WCCoCr-RE mixed powder. Then, the WCCoCr-RE mixed powder is put into a tubular furnace, and the heating temperature of the tubular furnace is set to 1200°C. At the same time, argon is filled into the tubular furnace to form an argon atmosphere environment in the tubular furnace. After the WCCoCr-RE mixed powder is heated in the tubular furnace for 2 hours, the WCCoCr-RE mixed powder is taken out, and the mixed powder is sieved through a 300-325 mesh sieve. The sieved mixed powder is the abrasive layer spray composite powder.

[0069] The inhibition layer spray composite powder and the grinding stone layer composite powder are added into deionized water to prepare a solution with a solid content of 32wt%. At the same time, polyacrylamide and ammonia suspension are added. After the pH value of the solution is adjusted to 8-9, the solution is ground for 2h using a rod-type sand mill. Then, the product is sieved through a 300-325 mesh sieve for use. At this time, the inhibition layer and the abrasion layer are both stored in the form of liquid phase materials, and the sealing layer spray composite powder is directly stored in the form of powder for use.

[0070] (2) In the spraying process of this embodiment, the method of using the spraying device is the same as that of Embodiment 1, except that the liquid phase material delivery rate in this embodiment is 40 mL / min.

[0071] (3) The sealing layer spraying method and the device use method in this embodiment are the same as those in Embodiment 1.

[0072] Example 3

[0073] In this embodiment, the protective coating is sprayed according to the following steps:

[0074] (1) Weigh the corresponding raw material powders according to the components of the protective coating in Table 1, and mix the raw material powders of the inhibition layer, the abrasion layer, and the sealing layer respectively to obtain the inhibition layer spray composite powder, the abrasion layer spray composite powder, and the sealing layer spray composite powder, wherein the inhibition layer and the sealing layer raw material powders are mixed by a mixer or the like.

[0075] The abrasive layer raw material powder is treated by the following method to obtain the abrasive layer spray composite powder: the abrasive layer raw material powder is added to a planetary ball mill, the planetary ball mill speed is set to 300r / min, the abrasive layer raw material powder is ball milled for 8h under the condition of a ball-to-material ratio of 2.5:1, and then RE powder and deionized water are added to the planetary ball mill, and polyvinyl alcohol, dispersant, and defoamer are added at the same time, and the ball milling is continued for 1h, and the polyvinyl alcohol content in the obtained slurry is 2%, the dispersant and defoamer content are both 0.1%, and the solid content is 50wt%. Then the slurry is added to a centrifugal spray dryer, the centrifugal spray dryer inlet temperature is set to 245℃, the outlet temperature is set to 100℃, the centrifugal spray dryer tower pressure is set to 0.05kPa, the peristaltic pump opening is set to 26%, the atomizer speed is set to 25000rpm, the centrifugal spray dryer is turned on, the centrifugal spray dryer is sprayed and powdered, and the powder produced by the centrifugal spray dryer is collected, that is, WCCoCr-RE mixed powder. Then the WCCoCr-RE mixed powder is put into a tubular furnace, the heating temperature of the tubular furnace is set to 1100°C, and argon is filled into the tubular furnace to form an argon atmosphere environment in the tubular furnace. After the WCCoCr-RE mixed powder is heated in the tubular furnace for 2.3 hours, the WCCoCr-RE mixed powder is taken out, and the mixed powder is sieved through a 300-325 mesh sieve. The sieved mixed powder is the abrasive layer spray composite powder.

[0076] The inhibition layer spray composite powder and the grinding stone layer composite powder are added into deionized water to prepare a solution with a solid content of 27wt%, and polyacrylamide and ammonia suspension are added at the same time. After the pH value of the solution is adjusted to 8-9, the solution is ground for 1.5h using a rod-type sand mill, and then the product is sieved through a 300-325 mesh sieve for use. At this time, the inhibition layer and the abrasion layer are both stored in the form of liquid phase materials, and the sealing layer spray composite powder is directly stored in the form of powder for use.

[0077] (2) In the spraying process of this embodiment, the method of using the spraying device is the same as that of Embodiment 1, except that the liquid phase material delivery rate in this embodiment is 35 mL / min.

[0078] (3) The sealing layer spraying method and the device use method in this embodiment are the same as those in Embodiment 1.

[0079] Comparative Example 1

[0080] The protective coating is sprayed in the same manner as in Example 1, except that the inhibition layer in the comparative example does not contain Si.

[0081] When the hydrogenation furnace and cyclone separator sprayed with the protective coating of this comparative example are used to produce SiHCl3, the impurity content of SiHCl3 is relatively high. Since the inhibition layer in comparative example 1 does not contain Si, the inhibition layer cannot prevent the diffusion of Fe, B, P, etc. from the inner wall of the hydrogenation furnace or the cyclone separator, and cannot react to generate NiCr. 15 Fe4B3Si4, on the one hand, causes the external diffusion elements to enter the reaction chamber of the hydrogenation furnace and enter into SiHCl3 during the fluidization process, resulting in an increase in the impurity content of SiHCl3, and on the other hand, it causes the corrosion resistance and oxidation resistance of the protective coating to decrease.

[0082] Comparative Example 2

[0083] This comparative example and Example 1 adopt the same method to spray the protective coating, the difference is that: the present invention uses thermal spraying technology to spray the sealing layer.

[0084] The protective coating of this comparative example has many pores, the surface roughness of the protective coating is high, and the wear resistance of the protective coating is poor. Since the sealing layer is sprayed with thermal spraying technology, the oxidation of Al and Si is relatively serious, and a large amount of PHE volatilizes and cannot fill the pores. Therefore, the protective coating has many pores and its wear resistance is poor.

[0085] Comparative Example 3

[0086] The protective coating was sprayed in the same method as in Example 1, except that the mixed powder of the abrasive layer was not heat treated in this comparative example, and the composite powder after ball milling and spray powdering was directly used to prepare the liquid phase material.

[0087] In this comparative example, the wear resistance of the wear layer is reduced. Due to the high ductility of the metal, it is difficult to evenly distribute the components in the abrasive layer spray composite powder. Although the migration of liquid metal can partially compensate for the unevenness during the thermal spraying process, metal element enrichment still often occurs in the protective coating. Among them, the segregation of Cr has a significant negative impact on the corrosion resistance of the protective coating. Since the mixed powder of the abrasive layer is heat-treated in Example 1, the reaction is affected by the chemical bonds and configuration of the intermetallic compound CoCr during the heat treatment. The intermetallic compound CoCr has covalent bonds and ionic bonds. In particular, the electronegativity of Cr is lower than that of Co, and Cr tends to lose electrons in the CoCr compound and become a positively charged ion. Therefore, the formation of Cr by the reaction of ionized Cr and C can be reduced. x C yenergy barrier. In addition, this is conducive to the formation of Co3W3C by the reaction of W, WC and Co, because both W and Co ions are chemically unstable after the WC and CoCr bonds are broken. At the same time, the uniform distribution of Co and Cr at the atomic scale enables W atoms to migrate short distances from the WC lattice to the WC / CoCr reaction front. Cr atoms occupy the W atomic sites and diffuse into the interior of the WC crystal. Therefore, a substitutional solid solution (W, Cr)C is formed in the WCCoCr spray powder. The mutual diffusion of W and Cr at the WC / CoCr interface ultimately leads to the dissolution of Cr in the WC structure. The above changes enhance the corrosion resistance of the wear layer.

[0088] pass Figure 1 It can be seen that after friction, the protective coating remains relatively flat and has no pores, and the coating roughness is between 0.05 and 0.1 μm, indicating that the protective coating of the present invention has high wear resistance.

[0089] pass Figure 2 It can be seen that the wear marks of the protective coating are relatively smooth and flat, without obvious furrows, which is typical fatigue wear. This shows that the bonding strength between the protective coating of the present invention and the protected surface is relatively high, and it is not easy to fall off during the abrasion period.

[0090] pass Figure 3 It can be seen that the friction coefficient of the protective coating of the present invention is less than 0.35, and the low friction coefficient further verifies that the protective coating of the present invention has high wear resistance.

[0091] pass Figure 4 It can be seen that after being corroded by the HCl corrosive solution, the coating has no obvious corrosion pits and no obvious peeling of the hard phase, which indicates that the protective coating of the present invention has high corrosion resistance.

[0092] In summary, the present invention optimizes the composition of the protective coating, combines a suitable spraying method, and uses a corresponding spraying device to make the bonding force between the internal parts and inner wall of the hydrogenation furnace and the protective coating stronger, thereby reducing the risk of product contamination during high-temperature operation of the hydrogenation furnace and increasing the service life of the hydrogenation furnace. At the same time, the wear resistance of the protective coating is effectively improved, the elements of the hydrogenation furnace and the cyclone separator themselves are prevented from external diffusion, the equipment maintenance cycle is reduced, and the product quality is guaranteed.

[0093] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A protective coating for a polysilicon hydrogenation system, characterized in that: The protective coating comprises an inhibition layer, an abrasion layer and a sealing layer, wherein the abrasion layer is between the inhibition layer and the sealing layer, and the inhibition layer is in contact with the protected surface of the hydrogenation system; The inhibiting layer comprises, by mass fraction, Cr: 15-19%, Co: 20-24%, Al: 11.5-13.5%, Y: 0.55-0.75%, Hf: 0.18-0.23%, Si: 0.32-0.45%, and the balance is Ni; The components of the abrasive layer include, by mass fraction, 8-12% Co, 3-8% Cr, 0.6-1.3% RE, and the balance is WC, wherein the RE is a rare earth oxide, including one or more of CeO2, La2O3, and Er2O3; The sealing layer comprises, by mass fraction, 25-35% Si, 2-6% polyphenylene ester, and the remainder Al.

2. A polysilicon hydrogenation system protective coating according to claim 1, characterized in that: The thickness of the inhibition layer is 40-90 μm, the thickness of the abrasion layer is 80-300 μm, and the thickness of the sealing layer is 10-30 μm.

3. A method for preparing a polysilicon hydrogenation system protective coating according to any one of claims 1 to 2, characterized in that: The preparation method comprises the following steps: (1) After respectively mixing the raw material powders of the inhibition layer, the abrasion layer, and the sealing layer, the inhibition layer spray composite powder, the abrasion layer spray composite powder, and the sealing layer spray composite powder are obtained, and the inhibition layer spray composite powder and the abrasion layer spray composite powder are respectively dissolved in deionized water, and a dispersant and a pH adjuster are added to adjust the pH of the liquid to 8-9, and then the liquid is ground, and then the liquid is passed through a 300-325 mesh sieve to prepare an inhibition layer liquid phase material and an abrasion layer liquid phase material; (2) In an argon atmosphere, the inhibition layer liquid phase material and the abrasion layer liquid phase material are sequentially sprayed on the protected surface of the hydrogenation system using a supersonic flame spraying technique to form an inhibition layer and an abrasion layer; (3) Within 30 seconds after the abrasive layer is sprayed, the sealing layer spray composite powder is sprayed onto the abrasive layer by cold spraying technology. During the spraying process, the sealing layer is simultaneously ground and polished. After grinding and polishing, the roughness is ≤0.1μm.

4. The preparation method according to claim 3, characterized in that: In the step (1), the dispersant is ammonium polyacrylate, the pH adjuster is ammonia suspension, the solid content of the composite powder in the inhibition layer liquid phase material and the abrasion layer liquid phase material is 20-32wt%, and the mass of the added dispersant is 0.5% of the mass of the composite powder.

5. The preparation method according to claim 3, characterized in that: The mixing process of the abrasive layer raw material powder specifically comprises the following steps: S1: ball milling WC, Co and Cr powders to obtain mixed powders, wherein the ball milling method is dry milling, the ball-to-material ratio is 2.5:1, the rotation speed is 300 r / min, and the dry milling time is 8 h; S2: adding the mixed powder obtained in step S1 and RE powder into deionized water, and adding polyvinyl alcohol, dispersant and defoamer to prepare slurry, and then continuing to ball-mill the slurry for 1 hour, wherein the solid content of the slurry is 50wt%, the amount of polyvinyl alcohol added is 1.5-2.5% of the mass of the mixed powder, the amount of dispersant added is 0.1% of the mass of the mixed powder, and the amount of defoamer added is 0.1% of the mass of the mixed powder, the dispersant is polyethylene glycol, and the defoamer is tributyl phosphate; S3: spraying the product obtained by ball milling in step S2 to obtain dry powder, wherein the air inlet temperature is 235-255° C., the air outlet temperature is 95-105° C., the spray pressure is 0.05 kPa, the peristaltic pump opening is 26%, and the atomizer speed is 25000 rpm; S4: In an argon atmosphere, heat-treating the dry powder obtained in step S3, and then sifting out the powder using a 300-325 mesh sieve, i.e., the abrasive layer spraying composite powder.

6. The preparation method according to claim 5, characterized in that: In step S4, the heat treatment temperature is 1000-1200° C., and the heat treatment time is 2-2.5 hours.

7. The preparation method according to claim 3, characterized in that: In the step (1), the particle size of the composite powder sprayed on the inhibition layer is 100-500 nm, the particle size of the composite powder sprayed on the abrasive layer is 13-20 mm, the particle size of the composite powder sprayed on the sealing layer is 35-45 μm, and the grinding time is 1-2 h.

8. The preparation method according to claim 3, characterized in that: In the step (2), the amount of kerosene in the supersonic flame spraying process is 27 LPH, the amount of oxygen is 800 NLPM, the liquid phase material delivery rate is 30-40 mL / min, the spraying distance is 340 mm, the spray gun moving speed is 10 mm / s, and the spraying direction of the spray gun is perpendicular to the protected surface.

9. The preparation method according to claim 3, characterized in that: In the step (3), the working gas and powder feeding gas in the cold spraying process are both nitrogen, the spraying distance is 250 mm, the spraying pressure is 1.5 MPa, and the spraying direction of the spray gun is perpendicular to the protected surface.

10. A protective coating spraying device for a polysilicon hydrogenation system, characterized in that: The spraying device is used in the preparation method according to claim 3, and the spraying device includes a spraying and polishing device for the inner wall of the hydrogenation furnace and a spraying and polishing device for the cyclone separator; The hydrogenation furnace inner wall spraying and polishing device comprises a cross-shaped track (1), a first guide member (2), a cold spray gun (3), a hot spray gun (4), an argon gas delivery pump (5), a hydrogenation furnace fixed frame (6), a rotating drive member (7), a bottom cover, a support frame, a second guide member (15), a telescopic rod (16), and a polishing grease (17). The hydrogenation furnace fixed frame (6) is fixedly sleeved on the outer shell of the hydrogenation furnace body (8). The hydrogenation furnace body (8) is arranged horizontally, and the axis of the hydrogenation furnace body (8) is horizontal. The hydrogenation furnace fixed frame (6) is rotatably mounted on the support frame. The transmission part of the rotating drive member (7) is fixedly connected to the hydrogenation furnace fixed frame (6). The rotating drive member (7) drives the hydrogenation furnace fixed frame (6) to rotate along the axis of the hydrogenation furnace body (8). The bottom cover is covered with the bottom of the hydrogenation furnace body (8), and a sealing gasket (9) is provided at the bottom where the bottom cover and the bottom of the hydrogenation furnace body (8) are covered. The cross-shaped track (1) is located inside the hydrogenation furnace body (8), and one end of the cross-shaped track (1) passes through the bottom cover and extends to the outside of the hydrogenation furnace body (8) for fixing. The first guide member (2) slides along the cross-shaped track (1). The cold spray gun (3) and the hot spray gun (4) are arranged in a cross shape and installed on the first guide member (2). The first guide member (2) controls the cold spray gun (3) and the hot spray gun (4) to rotate. The argon gas delivery pump (5) delivers argon gas to the inside of the hydrogenation furnace body (8) through a pipeline that passes through the bottom cover and extends to the inside of the hydrogenation furnace body (8). The bottom cover is provided with an argon gas outlet (10). The second guide member (15) slides along the cross-shaped track (1). The end of the fixed section of the telescopic rod (16) is installed on the second guide member (15). The polishing grease (17) is fixedly arranged at the end of the telescopic section of the telescopic rod (16). The cyclone separator spraying device comprises a first guide member (2), a cold spray gun (3), a hot spray gun (4), an argon gas delivery pump (5), a box (11), a motor (12), a slide rail (13), a second guide member (15), a telescopic rod (16), and a polishing grease (17). The slide rail (13) is located inside the box (11) and is installed on the bottom surface of the box (11). The first guide member (2) slides along the slide rail (13). The cold spray gun (3) and the hot spray gun (4) are arranged in a cross shape and are installed on the first guide member (2). The first guide member (2) controls the cold spray gun (3) and the hot spray gun (4) to rotate. The argon gas delivery pump (5) passes through the box. A pipe extending from a side wall of the housing (11) to the inside of the housing (11) transports argon gas into the housing (11); an argon gas outlet (10) is provided on the side wall of the housing (11); a cyclone separator body (14) is horizontally installed in the housing (11) via a motor (12); the motor (12) drives the cyclone separator body (14) to rotate around its axis; the cold spray gun (3) and the hot spray gun (4) spray material in a direction toward the cyclone separator body (14); the second guide member (15) slides along the slide rail (13); the end of the fixed section of the telescopic rod (16) is installed on the second guide member (15); and the polishing grease (17) is fixedly arranged at the end of the telescopic section of the telescopic rod (16).

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