An insulated high-temperature abrasion-resistant reduction furnace chassis and a method for preparing its coating

Abstract

The present invention discloses an insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis and a method for preparing a coating thereof, belonging to the technical field of polysilicon production. A first coating, a second coating and a third coating are sequentially sprayed on the surface of the reduction furnace chassis and the surface of the electrode; the first coating is formed by spraying a composite powder composed of Al2O3, Y2O3 and Na2O; the second coating is formed by thermally fusing dimethylformamide, polytetrafluoroethylene and silica sol; the third coating is formed by spraying a composite powder composed of Y2O3, Al2O3, Na2O, ZrO2 and yttrium-stabilized zirconia fiber; the first coating includes micron-sized powder and nano-sized powder. The coating of the insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis of the present invention has strong bonding force between coatings, high density, and excellent performances of high-temperature resistance, corrosion resistance, abrasion resistance and good insulation. The first coating has a bimodal coating of nano-sized particles and micron-sized particles, making the coating structure more compact, with high cracking toughness and hardness.

Description

Technical Field

[0001] The present invention belongs to the technical field of polysilicon production, and particularly relates to an insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis and a method for preparing a coating thereof. Background Art

[0002] High-purity polysilicon is the main raw material for preparing solar cells. The improved Siemens method is mainly used to prepare high-purity polysilicon. The process is as follows: Trichlorosilane and hydrogen are introduced into a reduction furnace, and a chemical vapor deposition reaction occurs on the surface of a silicon core at 1000-1100 °C to grow a polysilicon rod. The polysilicon reduction furnace mainly consists of a chassis and a furnace body. Among them, the chassis is the core component of the reduction furnace, and the structure and material properties of the chassis directly affect the growth quality of the silicon rod and the reduction energy consumption. An electrode device, a material inlet / outlet gas device, and a cooling device are also arranged on the chassis. The main material of the polysilicon reduction furnace chassis is stainless steel, and the material of the electrode is mainly copper. When starting the furnace to light the silicon core, since the voltage for breaking through the silicon core is as high as more than ten thousand volts, it is very easy to break through the insulator around the electrode. In addition, during the operation of the reduction furnace, due to the insulation problem between the reduction furnace and the electrode, the furnace is grounded and trips, and cannot operate normally. During the growth process of the silicon rod, a large amount of silicon particles will also be generated. The silicon particles flow with the gas, causing certain abrasion to the chassis and the electrode, and the generated metal enters the silicon rod during the deposition process, resulting in an increase in the impurity content of the silicon rod. Therefore, it is necessary to prepare an insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis to ensure the product quality and the stable operation of the reduction furnace. Summary of the Invention

[0003] Aiming at the above-mentioned shortcomings of the prior art, the present invention provides an insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis and a method for preparing a coating thereof.

[0004] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0005] An insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis, on the surfaces of the reduction furnace chassis and the electrode surface, a first coating, a second coating and a third coating are sequentially sprayed; the first coating is formed by spraying a composite powder composed of Al2O3, Y2O3 and Na2O; the second coating is formed by thermally fusing dimethylformamide, polytetrafluoroethylene and silica sol; the third coating is formed by spraying a composite powder composed of Y2O3, Al2O3, Na2O, ZrO2 and yttria-stabilized zirconia fibers; the first coating includes micron-sized powder and nano-sized powder, the proportion of micron-sized powder in the first coating is 8%-12%, and the proportion of nano-sized powder is 88%-92%; the particle size of the micron-sized powder is 80-230 μm, and the particle size of the nano-sized powder is 400-780 nm.

[0006] The surface of the chassis of the insulating, high-temperature resistant and abrasion-resistant reduction furnace of the present invention is successively sprayed with a first coating, a second coating and a third coating. The three coatings have high density and good adhesion, and have excellent high-temperature resistance, insulation and wear resistance. The Y2O3 contained in the first coating has strong dielectric properties. After doping with Al2O3 and Na2O, the insulation of the coating can be improved. Moreover, Y2O3 is added to Al2O3 to form yttria-toughened alumina, which improves the toughness of the first coating. In addition, the addition of Y2O3 can slow down the thermal stress during the formation and use of the coating. And the first coating contains a bimodal structure of nano-scale powder and micro-scale powder, which makes the structure of the first coating more dense, and the crack toughness and hardness are also significantly improved. Then, the second coating resin coating is thermally coated on the surface of the ultra-high insulation bimodal insulation layer, filling the pores of the first coating, and improving the density, adhesion and insulation of the coating. Finally, yttria-stabilized zirconia fibers are added to the third coating, further increasing the fracture toughness and abrasion resistance of the coating.

[0007] During the chemical vapor deposition of polysilicon on the chassis of the insulating, high-temperature resistant and abrasion-resistant reduction furnace of the present invention, when the micro-silica powder generated by the reaction abrades the surface of the coating, it will combine with the coating to generate mullite (Al2O3-SiO2) and SiO2 compounds, further enhancing the thermal stability and high-temperature insulation and wear resistance of the coating. The entire coating avoids the high-voltage breakdown of the electrode, reduces the frequency of grounding trips during the operation of the reduction furnace, and ensures the stable operation of the reduction furnace and the product quality.

[0008] As a preferred embodiment of the present invention, the thickness of the first coating is 130-370 μm, the thickness of the second coating is 0.1-20 μm, and the thickness of the third coating is 130-260 μm.

[0009] As a preferred embodiment of the present invention, in the composite powder composed of Al2O3, Y2O3 and Na2O, the mass percentage of Al2O3 is 64%-77%, the mass percentage of Y2O3 is 28%-41%, and the mass percentage of Na2O is 0.2%-1.5%.

[0010] As a preferred embodiment of the present invention, the mass ratio of dimethylformamide, polytetrafluoroethylene and silica sol is 41-55%: 28-41%: 18-23%.

[0011] The sum of the mass percentages of dimethylformamide, polytetrafluoroethylene and silica sol is 100%.

[0012] As a preferred embodiment of the present invention, in the composite powder of the wear-resistant layer, the mass percentage of Y2O3 is 5%-10%, the mass percentage of Al2O3 is 30%-41%, the mass percentage of Na2O is 0.2%-1.5%, the mass percentage of ZrO2 is 51%-65%, and the mass percentage of yttrium-stabilized zirconia fiber is 3%-8%.

[0013] As a preferred embodiment of the present invention, the diameter of the yttrium-stabilized zirconia fiber is 5-10 μm, and the length is 30-55 μm.

[0014] For the preparation method of the insulating high-temperature wear-resistant reduction furnace chassis of the present invention, a coating is sprayed on the chassis surface and the electrode surface of the reduction furnace chassis, and the method includes the following steps:

[0015] S1: Preheat the composite powder of the first coating, the organic matter of the second coating, and the composite powder of the third coating.

[0016] S2: Heat the substrate to 90-150 °C, and then spray the preheated composite powder of the first coating on the substrate surface by plasma spraying to form the first coating, and laser cladding is carried out simultaneously during plasma spraying.

[0017] S3: Coating the preheated organic matter of the second coating on the surface of the first coating by thermal cladding technology to form the second coating.

[0018] S4: Spray the preheated composite powder of the third coating on the surface of the second coating by plasma spraying to form the third coating, and laser cladding is carried out simultaneously during plasma spraying. After solidification, the insulating high-temperature wear-resistant reduction furnace chassis is obtained; the substrate is the chassis and the electrode of the reduction furnace chassis.

[0019] During spraying in the present invention, heating the substrate can reduce the cooling rate of the powder, thereby reducing the residual stress of the coating. To solve the problem that some microcracks will occur due to the release of thermal stress during the rapid cooling process after the molten droplets spread on the chassis surface and the electrode surface of the reduction furnace chassis, and at the same time, pores are generated because the molten droplets are not completely bonded to adjacent particles before solidification and shrinkage, the present invention adopts the simultaneous operation of laser cladding and plasma spraying. While the coating has not cooled, laser cladding is carried out simultaneously to further reduce the surface roughness of the coating, eliminate coating microcracks and pores, and at the same time increase the denseness and bonding strength between the coatings, which is beneficial to improving the insulation and friction and wear resistance of the coating, and at the same time reduces the energy required for laser cladding.

[0020] As a preferred embodiment of the present invention, in S1, the preheating temperature is 120-220 °C, and the time is 2-3 hours.

[0021] As a preferred embodiment of the present invention, the parameters of the plasma spraying technology in S2 and S4 are as follows: the current is 350 - 600 A, the voltage is 60 - 90 V, the hydrogen flow rate is 4 - 15 L / min, the argon flow rate is 5 - 20 L / min, the nitrogen flow rate is 10 - 12 L / min, the spraying distance is 40 - 120 mm, the gun scanning speed is 3 - 12 mm / s, and the powder feeding rate is 0.2 - 1.5 g / s.

[0022] As a preferred embodiment of the present invention, the power of the laser cladding is 2200 - 3800 w, and the spot diameter is 2 - 5 mm.

[0023] The device for spraying a coating on the surface of the insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis of the present invention includes a fixing frame 1. A heating plate 2 is fixedly installed on the inner wall of the top of the fixing frame 1. A rotating motor 3 is installed on one side of the fixing frame 1. The output end of the rotating motor 3 is connected to the reduction furnace chassis. The reduction furnace chassis rotates 360° to ensure that the insulating and wear-resistant coating sprayed by the spray gun 6 located directly below the reduction furnace chassis is sprayed on the surface of the reduction furnace chassis. The reduction furnace chassis is located directly below the heating plate 2 to ensure that the heating plate 2 can heat the reduction furnace chassis 10. The spraying device 4 includes a guide rail 5, a spray gun 6, a guiding member 7 connecting the guide rail 5 and the spray gun 6, and a laser gun 8 fixed on one side of the spray gun. The laser gun 8 is in the same direction as the gun head of the spray gun 6. A distance sensor is arranged inside the spray gun 6. The two ends of the guide rail 5 are fixedly connected to the bottom inner walls of the two sides of the fixing frame 1. The guide rail 5 and the fixing frame 1 form a closed inner cavity. The left and right parallel movement of the spray gun 6 is controlled through the guiding member 7 and the guide rail 5.

[0024] The device for spraying a coating on the surface of the electrode of the insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis of the present invention includes a fixing frame 1. Rotating motors 3 are installed on both sides of the fixing frame 1. The output end of the rotating motor 3 on one side is connected to the electrode 11, and the rotating motor on the other side is connected to a heating rod 9. The heating rod 9 is located inside the electrode 11. The spraying device 4 includes a guide rail 5, a spray gun 6, a guiding member 7 connecting the guide rail 5 and the spray gun 6, and a laser gun 8 fixed on one side of the spray gun. The laser gun 8 is in the same direction as the gun head of the spray gun 6. A distance sensor is arranged inside the spray gun 6. The two ends of the guide rail 5 are fixedly connected to the bottom inner walls of the two sides of the fixing frame 1. The guide rail 5 and the fixing frame 1 form a closed inner cavity. The left and right parallel movement of the spray gun 6 is controlled through the guiding member 7 and the guide rail 5. The guide rail 5 is located directly below the electrode.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] (1) The present invention prepares a multi-layer coating by using a plasma thermal spraying method and a thermal fusion cladding technology, including a first coating, a second coating, and a third coating. The surface coating of the insulating high-temperature abrasion-resistant reduction furnace chassis has strong bonding force between coatings and high density, so it has excellent properties of high temperature resistance, corrosion resistance, wear resistance, and good insulation. The first coating has a bimodal coating of nano-scale particles and micro-scale particles, making the coating structure more compact, with high cracking toughness and hardness.

[0027] (2) The present invention operates spraying and laser cladding simultaneously, that is, while the coating has not cooled, laser cladding is carried out simultaneously, reducing the energy required for laser cladding, and at the same time increasing the density and bonding strength of the coating. In the third coating, yttrium-stabilized zirconia fibers are added to the coating, further increasing the fracture toughness and abrasion resistance of the coating.

[0028] (3) The coating of the present invention increases the insulation and high-temperature abrasion-resistant properties of the reduction furnace chassis and the electrode, ensuring the stable operation of the reduction furnace and the product quality. One is to solve the problem that the reduction furnace cannot operate normally due to the grounding trip caused by the insulation problem between the reduction furnace and the electrode during the operation of the reduction furnace; the other is to solve the problem that the impurity content of the silicon rod increases due to the abrasion of the electrode by silicon particles and the entry of the chassis metal into the silicon rod during the deposition process. Description of the Drawings

[0029] Figure 1 It is a schematic diagram of the device for spraying the coating on the surface of the insulating high-temperature abrasion-resistant reduction furnace chassis described in the present invention.

[0030] Figure 2 It is a schematic diagram of the device for spraying the coating on the surface of the electrode of the insulating high-temperature abrasion-resistant reduction furnace chassis of the present invention.

[0031] Among them, 1, fixed frame; 2, heating plate; 3, rotating motor; 4, spraying device; 5, guide rail; 6, spray gun; 7, guiding member; 8, laser gun; 9, heating rod; 10, reduction furnace chassis; 11, electrode. Detailed Embodiments

[0032] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0033] The embodiments and comparative examples of the present invention use the device for spraying the coating on the surface of the insulating high-temperature abrasion-resistant reduction furnace chassis and the device for spraying the coating on the surface of the electrode of the insulating high-temperature abrasion-resistant reduction furnace chassis.

[0034] The device for spraying a coating on the surface of the chassis of an insulating, high-temperature resistant and abrasion-resistant reduction furnace according to the present invention includes a fixing frame 1. A heating plate 2 is fixedly installed on the inner wall of the top of the fixing frame 1. A rotating motor 3 is installed on one side of the fixing frame 1. The output end of the rotating motor 3 is connected to the reduction furnace chassis. The reduction furnace chassis rotates 360° to ensure that the insulating and wear-resistant coating sprayed by the spray gun 6 located directly below the reduction furnace chassis is sprayed on the surface of the reduction furnace chassis. The reduction furnace chassis is located directly below the heating plate 2 to ensure that the heating plate 2 can heat the reduction furnace chassis 10. The spraying device 4 includes a guide rail 5, a spray gun 6, a guiding member 7 connecting the guide rail 5 and the spray gun 6, and a laser gun 8 fixed on one side of the spray gun. The laser gun 8 is in the same direction as the gun head of the spray gun 6. A distance sensor is provided inside the spray gun 6. Both ends of the guide rail 5 are fixedly connected to the bottom of the inner walls on both sides of the fixing frame 1. The guide rail 5 and the fixing frame 1 form a sealed inner cavity. The left and right parallel movement of the spray gun 6 is controlled by the guiding member 7 and the guide rail 5.

[0035] The device for spraying a coating on the surface of the electrode of the chassis of an insulating, high-temperature resistant and abrasion-resistant reduction furnace according to the present invention includes a fixing frame 1. Rotating motors 3 are installed on both sides of the fixing frame 1. The output end of the rotating motor 3 on one side is connected to the electrode 11, and the rotating motor on the other side is connected to a heating rod 9. The heating rod 9 is located inside the electrode. The spraying device 4 includes a guide rail 5, a spray gun 6, a guiding member 7 connecting the guide rail 5 and the spray gun 6, and a laser gun 8 fixed on one side of the spray gun. The laser gun 8 is in the same direction as the gun head of the spray gun 6. A distance sensor is provided inside the spray gun 6. Both ends of the guide rail 5 are fixedly connected to the bottom of the inner walls on both sides of the fixing frame 1. The guide rail 5 and the fixing frame 1 form a sealed inner cavity. The left and right parallel movement of the spray gun 6 is controlled by the guiding member 7 and the guide rail 5. The guide rail 5 is located directly below the electrode.

[0036] Examples 1 - 4

[0037] The preparation method of the chassis of the insulating, high-temperature resistant and abrasion-resistant reduction furnace in this example includes the following steps:

[0038] (1) According to Tables 1, 2 and 3, prepare the composite powder of the first coating, the organic matter of the second coating, and the composite powder of the third coating; preheat the composite powder of the first coating, the organic matter of the second coating, and the composite powder of the third coating at 220 °C for 2 hours.

[0039] (2) Heat the substrate to 150 °C, and then spray the composite powder of the preheated first coating on the surface of the substrate by plasma spraying technology to form the first coating, while performing laser cladding during plasma spraying; the current of the plasma spraying technology is 600 A, the voltage is 70 V, the hydrogen flow rate is 4 L / min, the argon flow rate is 20 L / min, the nitrogen flow rate is 12 L / min, the spraying distance is 40 mm, the gun scanning speed is 12 mm / s, and the powder feeding rate is 1.5 g / s; the power of the laser cladding is 3800 w and the spot diameter is 2 mm. The first coating includes micron-sized powder and nano-sized powder. The proportion of micron-sized powder in the first coating is 12%, and the proportion of nano-sized powder is 88%; the particle size of the micron-sized powder is 80 - 230 μm, and the particle size of the nano-sized powder is 400 - 780 nm; the thickness of the first coating is 130 μm; the substrate is the chassis and electrode of an insulating high-temperature abrasion-resistant reduction furnace chassis.

[0040] (3) Spray the organic matter of the preheated second coating on the surface of the first coating by thermal spraying technology to form the second coating, and the thermal spraying temperature is 360 °C. The thickness of the second coating is 20 μm.

[0041] (4) Spray the composite powder of the preheated third coating on the surface of the second coating by plasma spraying technology to form the third coating, while performing laser cladding during plasma spraying, and obtain the insulating high-temperature abrasion-resistant reduction furnace chassis after solidification. The current of the plasma spraying technology is 500 A, the voltage is 90 V, the hydrogen flow rate is 12 L / min, the argon flow rate is 4 L / min, the nitrogen flow rate is 12 L / min, the spraying distance is 40 mm, the gun scanning speed is 3 mm / s, and the powder feeding rate is 0.2 g / s; the power of the laser cladding is 2200 w and the spot diameter is 5 mm. The particle size of the third coating is 130 μm, and the thickness of the third coating is 130 μm.

[0042] Table 1 Weight percentage content of each component of the composite powder of the first coating

[0043] <![CDATA[Y2O3 / wt.%]]> <![CDATA[Al2O3 / wt.%]]> <![CDATA[Na2O / wt.%]]> Example 1 56 43 1 Example 2 65 33.5 1.5 Example 3 52.8 47 0.2

[0044] Table 2 Weight percentage content of each component of the organic matter of the second coating

[0045]

[0046] Table 3 Weight percentage content of each component of the composite powder of the third coating

[0047]

[0048] Example 4

[0049] The preparation method of the insulating high-temperature abrasion-resistant reduction furnace chassis described in this example includes the following steps:

[0050] (1) According to Example 1, prepare the composite powder for the first coating, the organic substance for the second coating, and the composite powder for the third coating; preheat the composite powder for the first coating, the organic substance for the second coating, and the composite powder for the third coating at 120 °C for 3 hours;

[0051] (2) Heat the substrate to 90 °C, and then spray the preheated composite powder for the first coating on the surface of the substrate by plasma spraying technology to form the first coating, while laser cladding is carried out during plasma spraying; the current of the plasma spraying technology is 350 A, the voltage is 90 V, the hydrogen flow rate is 15 L / min, the argon flow rate is 5 L / min, the nitrogen flow rate is 10 L / min, the spraying distance is 120 mm, the gun scanning speed is 3 mm / s, and the powder feeding rate is 0.2 g / s; the power of the laser cladding is 2200 w and the spot diameter is 5 mm. The first coating includes micron-sized powder and nano-sized powder, the proportion of micron-sized powder in the first coating is 8%, and the proportion of nano-sized powder is 92%; the particle size of the micron-sized powder is 80 - 230 μm, and the particle size of the nano-sized powder is 400 - 780 nm; the thickness of the first coating is 370 μm; the substrate is the chassis and electrode of an insulating high-temperature abrasion-resistant reduction furnace chassis.

[0052] (3) Spray the preheated organic substance for the second coating on the surface of the first coating by thermal cladding technology to form the second coating, and the thermal cladding temperature is 360 °C, and the thickness of the second coating is 0.1 μm.

[0053] (4) Spray the preheated composite powder for the third coating on the surface of the second coating by plasma spraying technology to form the third coating, while laser cladding is carried out during plasma spraying, and an insulating high-temperature abrasion-resistant reduction furnace chassis is obtained after solidification. The current of the plasma spraying technology is 400 A, the voltage is 60 V, the hydrogen flow rate is 12 L / min, the argon flow rate is 4 L / min, the nitrogen flow rate is 12 L / min, the spraying distance is 40 mm, the gun scanning speed is 3 mm / s, and the powder feeding rate is 0.2 g / s; the power of the laser cladding is 2200 w and the spot diameter is 5 mm. The particle size of the third coating is 15 μm, and the thickness of the third coating is 260 μm.

[0054] Comparative Examples 1 - 5

[0055] The only difference between the preparation method of the insulating high-temperature abrasion-resistant reduction furnace chassis described in the comparative examples and Example 1 is that the weight percentage contents of each component of the composite powder for the first coating, the organic substance for the second coating, and the composite powder for the third coating are prepared according to Tables 4 - 6.

[0056] Table 4 Weight percentage contents of each component of the composite powder for the first coating

[0057] <![CDATA[Y2O3 / wt.%]]> <![CDATA[Al2O3 / wt.%]]> <![CDATA[Na2O / wt.%]]> Comparative Example 1 56 44 0 Comparative Example 2 98.5 0 1.5 Comparative Example 3 56 43 1 Comparative Example 4 56 43 1 Comparative Example 5 56 43 1

[0058] Percentage by weight of each component of the organic matter in the second coating, Table 5

[0059]

[0060]

[0061] Percentage by weight of each component of the composite powder in the third coating, Table 6

[0062]

[0063] Comparative Example 6

[0064] The only difference between the preparation method of the insulating, high-temperature resistant, abrasion-resistant reduction furnace chassis described in the comparative example and Example 1 is that: in step (2), the substrate was not heated.

[0065] Comparative Example 7

[0066] The only difference between the preparation method of the insulating, high-temperature resistant, abrasion-resistant reduction furnace chassis described in the comparative example and Example 1 is that: laser cladding was not carried out in steps (2)-(4).

[0067] Comparative Example 8

[0068] The only difference between the preparation method of the insulating, high-temperature resistant, abrasion-resistant reduction furnace chassis described in the comparative example and Example 1 is that: in steps (2)-(4), laser cladding was carried out after the coating was cooled.

[0069] Effect Example

[0070] The insulating, high-temperature resistant, abrasion-resistant reduction furnace chassis obtained in the examples and comparative examples was subjected to performance testing, and the results are shown in Table 7.

[0071] Table 7

[0072]

[0073]

[0074] Comparing Examples 1-4 with Comparative Examples 1-8 based on the data in Table 7, the comprehensive performance of the insulated high-temperature abrasion-resistant reduction furnace chassis prepared by the present invention is the best, having the effects of high temperature resistance, abrasion resistance, and good insulation. Comparing Example 1 with Comparative Examples 1-5, it can be seen that the performance of Example 1 is superior to that of Comparative Examples 1-5, indicating that the components of the first coating and the third coating have a synergistic effect to jointly achieve the effects of high temperature resistance, abrasion resistance, and good insulation. In particular, the toughness of the coating in Comparative Example 3 has significantly decreased, indicating that the addition of yttrium-stabilized zirconia fibers has a greater impact on the coating toughness. From Example 1 and Comparative Example 6, it can be seen that the insulation and fracture toughness of the reduction furnace chassis described in Comparative Example 6 have decreased, and the wear rate and porosity have increased, indicating that when spraying in the present invention, heating the substrate can reduce the cooling rate of the powder, thereby reducing the residual stress of the coating, and further improving the wear resistance, toughness, and insulation of the insulated high-temperature abrasion-resistant reduction furnace chassis. According to Example 1 and Comparative Examples 7-8, it can be seen that the insulation and fracture toughness of the reduction furnace chassis described in Comparative Examples 7 and 8 have decreased, and the wear rate and porosity have increased, indicating that when spraying and laser cladding are carried out simultaneously, that is, while the coating has not cooled, laser cladding is carried out simultaneously, reducing the energy required for laser cladding, and at the same time increasing the denseness and bonding strength between the coatings, thereby improving the high temperature resistance, abrasion resistance, and insulation of the reduction furnace chassis and the electrode.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis, characterized in that, The first coating, the second coating and the third coating are successively sprayed on the chassis surface and the electrode surface of the reduction furnace chassis; the first coating is formed by spraying a composite powder composed of Al2O3, Y2O3 and Na2O; the second coating is formed by dimethylformamide, polytetrafluoroethylene and silica sol; the third coating is formed by spraying a composite powder composed of Y2O3, Al2O3, Na2O, ZrO2 and yttrium-stabilized zirconia fiber; the first coating includes micron-level powder and nano-level powder, the proportion of micron-level powder in the first coating is 8%-12%, and the proportion of nano-level powder is 88%-92%; the particle size of the micron-level powder is 80-230μm, and the particle size of the nano-level powder is 400-780nm; Spraying coatings on the chassis surface and the electrode surface of the reduction furnace chassis includes the following steps: S1: Preheat the composite powder of the first coating, the organic substances of the second coating, and the composite powder of the third coating; S2: Heat the substrate to 90-150°C, and then spray the preheated composite powder of the first coating on the substrate surface by plasma spraying technology to form the first coating, and laser cladding is carried out while plasma spraying; S3: Coating the preheated organic substances of the second coating on the surface of the first coating by thermal cladding technology to form the second coating; S4: Spray the preheated composite powder of the third coating on the surface of the second coating by plasma spraying technology to form the third coating, and laser cladding is carried out while plasma spraying. After solidification, an insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis is obtained; the substrate is the chassis and electrode of the reduction furnace chassis.

2. The insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis according to claim 1, characterized in that, In the composite powder composed of Al2O3, Y2O3 and Na2O, the mass percentage of Al2O3 is 64%-77%, the mass percentage of Y2O3 is 28%-41%, and the mass percentage of Na2O is 0.2%-1.5%.

3. The insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis according to claim 1, characterized in that, The weight ratio of dimethylformamide, polytetrafluoroethylene and silica sol is 41-55%: 28-41%: 18-23%.

4. The insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis according to claim 1, characterized in that, In the composite powder of the third coating, the mass percentage of Y2O3 is 5%-10%, the mass percentage of Al2O3 is 30%-41%, the mass percentage of Na2O is 0.2%-1.5%, the mass percentage of ZrO2 is 51%-65%, and the mass percentage of yttrium-stabilized zirconia fiber is 3%-8%.

5. The insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis according to claim 1, characterized in that, The thickness of the first coating is 130-370μm, the thickness of the second coating is 0.1-20μm, and the thickness of the third coating is 130-260μm.

6. The insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis according to claim 1, characterized in that, The parameters of the plasma spraying technology in S2 and S4 are: current is 350-600A, voltage is 60-90V, hydrogen flow rate is 4-15L / min, argon flow rate is 5-20L / min, nitrogen flow rate is 10-12L / min, spraying distance is 40-120mm, gun scanning speed is 3-12mm / s, powder feeding rate is 0.2-1.5g / s; the power of the laser cladding is 2200-3800w, and the spot diameter is 2-5mm.

7. The insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis according to claim 1, characterized in that, Device for spraying coating on surface of insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis, comprising a fixing frame (1), a heating plate (2) fixedly installed on the inner wall of the top of the fixing frame (1), a rotating motor (3) installed on one side of the fixing frame (1), the output end of the rotating motor (3) being connected to the reduction furnace chassis, and the reduction furnace chassis rotating 360° to ensure that the insulating and wear-resistant coating sprayed by a spray gun (6) located directly below the reduction furnace chassis is sprayed on the surface of the reduction furnace chassis. The reduction furnace chassis is located directly below the heating plate (2) to ensure that the heating plate (2) can heat the reduction furnace chassis (10). The spraying device (4) comprises a guide rail (5), a spray gun (6), a guiding member (7) connecting the guide rail (5) and the spray gun (6), and a laser gun (8) fixed to one side of the spray gun. The laser gun (8) is in the same direction as the gun head of the spray gun (6). A distance sensor is arranged inside the spray gun (6). The two ends of the guide rail (5) are fixedly connected to the bottom inner walls on both sides of the fixing frame (1). The guide rail (5) and the fixing frame (1) form a sealed inner cavity, and the left and right parallel movement of the spray gun (6) is controlled through the guiding member (7) and the guide rail (5).

8. The insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis according to claim 1, characterized in that, Device for spraying coating on surface of electrode of insulating, high-temperature resistant and abrasion-resistant reduction furnace chassis, comprising a fixing frame (1), rotating motors (3) installed on both sides of the fixing frame (1), the output end of a rotating motor (3) on one side being connected to an electrode (11), and the rotating motor on the other side being connected to a heating rod (9). The heating rod (9) is located inside the electrode (11). The spraying device (4) comprises a guide rail (5), a spray gun (6), a guiding member (7) connecting the guide rail (5) and the spray gun (6), and a laser gun (8) fixed to one side of the spray gun. The laser gun (8) is in the same direction as the gun head of the spray gun (6). A distance sensor is arranged inside the spray gun (6). The two ends of the guide rail (5) are fixedly connected to the bottom inner walls on both sides of the fixing frame (1). The guide rail (5) and the fixing frame (1) form a sealed inner cavity, and the left and right parallel movement of the spray gun (6) is controlled through the guiding member (7) and the guide rail (5). The guide rail (5) is located directly below the electrode.

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