Corrosion-resistant crucible for polycrystalline silicon ingot casting and its preparation method

Abstract

This invention relates to the field of crucible technology, specifically to a corrosion-resistant crucible for polycrystalline silicon ingot casting and its preparation method. The crucible includes a heat dissipation base, and at least one layer of reinforcing mesh conforming to the crucible's outline is provided in the inner wall of the crucible body. The crucible body is made of a mixed ceramic slurry. This corrosion-resistant crucible for polycrystalline silicon ingot casting can achieve more efficient heat conduction, and the bottom heat dissipation structure can reduce the problem of large differences in heat dissipation between the sidewall and the bottom. At the same time, both the reinforcing mesh and the mixed ceramic slurry can improve the mechanical properties and heat dissipation of the crucible. Furthermore, the mixed ceramic slurry can effectively block the corrosion of the crucible by acid and alkali residues in the silicon material during the ingot casting process, thereby improving the crucible's corrosion resistance, reducing the overflow rate of the crucible, improving casting efficiency, reducing production costs, and making it suitable for large-scale industrial production.

Description

Technical Field

[0001] This invention relates to the field of crucible technology, specifically to corrosion-resistant crucibles for polycrystalline silicon ingots and their preparation methods. Background Technology

[0002] Currently, in the preparation process of polycrystalline silicon ingots, quartz ceramic crucibles are essential supporting equipment used in the polycrystalline silicon ingot casting stage. Within the crucible, silicon material undergoes high-temperature melting, crystal growth, annealing, cooling, and then directional solidification and crystallization, ultimately casting into a polycrystalline silicon ingot. The silicon ingot is then cut into silicon wafers according to technical requirements, which can then be used as the substrate material for manufacturing solar cells.

[0003] However, current quartz ceramic crucibles are mainly prepared by slip casting to form the blank, and then sintered at around 1200℃ to obtain a density of approximately 1.92 g / cm³. 3 The ceramic crucible has a low thermal conductivity, typically only 0.86-0.88 W·m. -1 / K. During the directional solidification stage of ingot casting, the thermal conductivity is low, and heat dissipation is slow, resulting in a significant difference in heat dissipation between the sidewalls and the bottom. Traditional ceramic crucibles are primarily made of silicon dioxide ceramic, with crystalline and glassy phases. During the preparation of cast polycrystalline silicon, the acid and alkali residues in the silicon material, in prolonged contact with the crucible during raw material melting and crystal growth, can cause corrosion. This corrosion can easily lead to crucible breakage and overflow during crystal cooling. Therefore, it is necessary to avoid overflow caused by crucible corrosion and to improve the thermal conductivity of the crucible to enhance its heat dissipation performance. In light of this, we propose a corrosion-resistant crucible for polycrystalline silicon ingot casting and its preparation method. Summary of the Invention

[0004] To overcome the above deficiencies, the present invention provides a corrosion-resistant crucible for polycrystalline silicon ingot casting and a method for preparing the same.

[0005] The technical solution of this invention is:

[0006] A corrosion-resistant crucible for polycrystalline silicon ingot casting includes a heat dissipation base. The inner wall of the crucible body is provided with at least one layer of strong rib mesh that conforms to the outline of the crucible. The crucible body is made of mixed ceramic slurry.

[0007] Preferably, a ring-shaped cylindrical heat dissipation base is fixedly connected to the bottom of the crucible, and a heat-conducting block corresponding to the bottom of the heat dissipation base is installed inside the heat dissipation base. The heat dissipation base has heat dissipation holes, and the heat-conducting block has grooves that increase the heat-conducting contact area. The ring-shaped cylindrical heat dissipation base, in conjunction with the heat conduction effect of the heat-conducting block, can quickly dissipate the heat from the bottom of the crucible, avoiding the problem of poor heat dissipation at the bottom of the crucible. The heat-conducting block can be made of aluminum, and the grooves on its surface increase the surface area to promote heat dissipation efficiency.

[0008] Preferably, the specific components of the mixed ceramic slurry are in the following proportions by mass: 80-100 parts silica, 20-28 parts thermally conductive filler, 10-15 parts zirconium oxide, 5-10 parts alumina, 0.8-1.5 parts defoamer, 0.6-1.2 parts monomer, 1-2 parts crosslinking agent, 0.5-1 part coagulation catalyst, and 0.5-1.2 parts dispersant.

[0009] It should be noted that the main raw material for crucible production is currently silica. The purpose of using highly thermally conductive fillers is to improve its thermal conductivity. Combined with the physical properties of zirconium oxide and alumina, it has high physical and mechanical strength and corrosion resistance, effectively enhancing the mechanical properties of the crucible. Furthermore, the highly thermally conductive fillers, along with zirconium oxide and alumina, can hinder or mitigate the corrosive effects of acids and alkalis on the crucible during the silicon ingot casting process. In addition, the strong ribbed mesh layer improves the overall strength of the crucible. Overall, the fillers enhance mechanical strength, inhibit corrosion, improve corrosion resistance, and, due to their high thermal conductivity, can dissipate heat quickly, which helps to shorten the ingot casting time and improve production efficiency.

[0010] Preferably, the substrate of the highly thermally conductive filler has a thermal conductivity of not less than 151 W·m. -1 / K, and the absolute value of the coefficient of thermal expansion is less than 4.2×10 -6 / K materials.

[0011] Preferably, the high thermal conductivity filler substrate is made of any one or more of carbon fiber, carbon nanotubes, graphene, and graphite, and the substrate surface is coated with a metal lubricating film. The substrate surface is not smooth and has many micropores, resulting in poor wettability with zirconium oxide and alumina, leading to poor dispersion. The substrate itself tends to agglomerate, making direct mixing detrimental to the uniform distribution of the crucible material. However, by coating with a metal lubricating film, a metal layer is formed on the substrate surface, which reduces the substrate porosity and simultaneously forms an inner and outer core structure. This helps to simultaneously improve the material strength of the high thermal conductivity filler, thereby further enhancing the crucible strength while maintaining its high thermal conductivity.

[0012] Preferably, the reinforcing mesh layer is made of copper or aluminum mesh with a thickness of 0.05mm-0.25mm. Copper or aluminum mesh has excellent strength and thermal conductivity, and the contour-fitting structure can achieve more stable overall crucible strength.

[0013] A method for preparing a corrosion-resistant crucible for polycrystalline silicon ingots, wherein the method for preparing the highly thermally conductive filler is as follows:

[0014] Step 1: First, weigh out the dry and clean high thermal conductivity filler substrate, grind it to a fineness of 150-600 mesh and sieve it for later use;

[0015] Step 2: Weigh out the coating salt compound and sodium hypophosphite used for metal lubrication film with a molar mass ratio of 1:2;

[0016] Step 3: Weigh the high thermal conductivity filler substrate from Step 1, control the solid-liquid ratio to 1:5-10, put it into water and mix and stir, then add sufficient coating salt compound and sodium hypophosphite and mix well.

[0017] Step 4: Simultaneously add ethyl formate complexing agent (5-8% by weight of the highly thermally conductive filler substrate) and boric acid buffer (3-5% by weight of the highly thermally conductive filler substrate) to the mixture; ferric chloride catalyst (0.8-2.5% by weight of the highly thermally conductive filler substrate) can also be added to the mixture.

[0018] Step 5: Stir the mixture and let it stand for 3-8 minutes until no more bubbles are generated. Then, the metal lubricating film is deposited and filtered to obtain the filter material. After drying the filter material, it does not need to be ground. It is directly sieved through a 150-600 mesh sieve again. The residue is removed to obtain a uniform particle size of highly thermally conductive filler.

[0019] Preferably, the coating salt compound is any one of titanyl sulfate, tungsten disulfide, chromium sulfate, and nickel sulfate.

[0020] It is important to explain that the coating salt compounds used all contain positively valent metal ions, and the catalyst ferric chloride also includes ferric ions. During the formation of the metal lubricating film, the ferric ions are reduced to divalent, exhibiting reducing properties, which can promote the reduction of positively valent metal ions to elemental metals, thus lowering their valence. Furthermore, if ferric ions are not used, sodium hypophosphite can be hydrolyzed to produce hypophosphite ions, which then undergo further surface dehydrogenation to produce active hydrides, which also possess reducing properties and can reduce positively valent metal ions, such as nickel sulfate: 2H₂PO₄. 2- +2H2O+Ni 2+ →Ni + H₂↑ + 4H + +2HPO3 2- Positive-valent metal ions will be deposited onto the substrate surface to complete the coating based on this reaction principle. Hydrogen gas will be released during this process. When no gas is produced, it indicates that the deposition coating is complete.

[0021] Preferably, the method for preparing the new mixed ceramic slurry is as follows:

[0022] Step 1: Grind silica, zirconium oxide, and alumina separately in a ball mill at 800-1200 r / min for 4.5-8 hours. Then dry the ball-milled powder for later use. Mix them in a roller mixer according to the required mass proportions.

[0023] Step 2: Weigh 0.6-1.2 parts of acrylamide or methacrylamide monomer and 1-2 parts of N,N-methylenebisacrylamide crosslinking agent and dissolve them in deionized water to obtain a premixed solution;

[0024] Step 3: Next, add 0.5-1.2 parts of dispersant to a small amount of deionized water, then add 20-28 parts of highly thermally conductive filler and the mixture from Step 1. Then continue to add an appropriate amount of deionized water to dilute and control the solid content to 75-85%. Stir evenly to obtain a slurry. Controlling the solid content is to avoid the slurry being too thin and causing sedimentation, and also to avoid the solid content being too high and making it difficult to mix thoroughly.

[0025] Step 4: Add the premixed liquid to the slurry, adjust the pH to 6-8 with ammonia water, and then add 0.8-1.5 parts of defoamer and 0.5-1 parts of coagulation catalyst to obtain a new mixed ceramic slurry.

[0026] Preferably, the specific steps are as follows: Using a stainless steel crucible mold, a measured amount of the mixed ceramic slurry is injected into the mold. The oven temperature is controlled at 40-80℃ for drying and curing. After demolding, a constant temperature of 38-45℃ and 45-55% humidity is applied for curing for at least 72 hours. Finally, the crucible is placed in a calcining furnace. The heating rate is controlled at 2-2.5℃ / min, and the temperature is raised to 780-850℃ and held for 0.5-1.5 hours. The heating rate is then controlled at 1-1.5℃ / min, raising the temperature to 1180-1250℃ and holding for calcination for 2-4.5 hours. Finally, the cooling rate is controlled at 1.5-3℃ / min, and the crucible is removed after cooling to room temperature, resulting in a sintered crucible. The heating to 780-850℃ and holding for drying is mainly for dehydration, avoiding cracking caused by excessively rapid dehydration. Cooling to room temperature also avoids breakage caused by excessive temperature differences.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] This corrosion-resistant crucible for polycrystalline silicon ingot casting achieves more efficient thermal conductivity, and the bottom heat dissipation structure reduces the problem of large differences in heat dissipation between the sidewalls and the bottom. At the same time, the reinforcing mesh layer and the mixed ceramic slurry can improve the mechanical properties and heat dissipation of the crucible. Furthermore, the mixed ceramic slurry can effectively block the corrosion of the crucible by acid and alkali residues in the silicon material during the ingot casting process, thereby improving the crucible's corrosion resistance and reducing the overflow rate. This is beneficial for improving ingot casting efficiency, reducing production costs, and is suitable for large-scale industrial production. Attached Figure Description

[0029] Figure 1 This is a cross-sectional schematic diagram of the overall structure of the present invention.

[0030] The meanings of the labels in the diagram are as follows:

[0031] 1. Crucible body; 2. Heat dissipation base; 201. Heat dissipation hole; 3. Heat-conducting block; 301. Groove. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Please see Figure 1 The present invention will describe the above technical solution in detail through the following embodiments:

[0034] Example 1

[0035] A corrosion-resistant crucible for polycrystalline silicon ingot casting includes a heat dissipation base 2 and a copper mesh reinforcing layer with a thickness of 0.15 mm that fits the outline of the crucible body 1 in the inner wall. The crucible body 1 is made of mixed ceramic slurry.

[0036] A ring-shaped cylindrical heat dissipation base 2 is fixedly connected to the bottom of the crucible, and a heat-conducting block 3 corresponding to the bottom of the heat dissipation base 2 is installed inside the heat dissipation base 2. The heat dissipation base 2 is provided with heat dissipation holes 201, and the heat-conducting block 3 is provided with grooves 301 that can increase the heat conduction contact area. Figure 1 As shown in the structure, the heat conduction fast 3 uses an aluminum heat sink.

[0037] The specific components of the mixed ceramic slurry are as follows: 100 parts silica, 20 parts thermally conductive filler, 10 parts zirconium oxide, 5 parts alumina, 1 part defoamer GPE50, 1.2 parts acrylamide monomer, 2 parts N,N-methylenebisacrylamide crosslinking agent, 0.8 parts coagulation catalyst triethanolamine, and 1.2 parts polyacrylic acid dispersant.

[0038] The base material of the high thermal conductivity filler has a thermal conductivity of not less than 151 W·m. -1 / K, and the absolute value of the coefficient of thermal expansion is less than 4.2×10 -6 / K graphite, and the substrate surface is coated with a metal lubricating film.

[0039] The preparation method of corrosion-resistant crucibles for polycrystalline silicon ingots, and the specific preparation method of highly thermally conductive fillers are as follows:

[0040] Step 1: First, weigh out the dry and clean graphite, grind it to a fine 150 mesh and sieve it for later use;

[0041] Step 2: Weigh out 2 mol of titanium dioxide sulfate and 4 mol of sodium hypophosphite for the metal lubrication film;

[0042] Step 3: Weigh the graphite from Step 1, control the solid-liquid ratio to 1:5, add it to water and mix and stir, then add titanium sulfate and sodium hypophosphite and mix well.

[0043] Step 4: Simultaneously add ethyl formate complexing agent (5% by weight of graphite) and boric acid buffer (3% by weight of graphite) to the mixture; and add ferric chloride catalyst (1.5% by weight of the thermally conductive filler substrate) to the mixture.

[0044] Step 5: Stir the mixture until no more bubbles are generated. Let it stand for 5 minutes to complete the titanium lubricating film coating. Filter to obtain filter material. After drying the filter material, it does not need to be ground. It is directly sieved through a 150-mesh sieve again. After removing the sieve residue, a uniformly sized, highly thermally conductive filler is obtained.

[0045] The preparation method of the mixed ceramic slurry is as follows:

[0046] Step 1: Grind silica, zirconium oxide and alumina separately in a ball mill at 800 r / min for 6 hours. Then dry the ball-milled powder for later use. Mix them in a roller mixer according to the required mass proportions.

[0047] Step 2: Weigh acrylamide monomer and N,N-methylenebisacrylamide crosslinking agent and dissolve them in deionized water to obtain a premixed solution;

[0048] Step 3: Next, add polyacrylic acid dispersant to a small amount of deionized water, then add the highly thermally conductive filler and the mixture from Step 1, then continue to add an appropriate amount of deionized water to dilute and control the solid content to 75%, and stir evenly to obtain a slurry;

[0049] Step 4: Add the premixed liquid to the slurry, adjust the pH to 6.5 with ammonia water, and then add the defoamer GPE50 and the coagulation catalyst triethanolamine to obtain a new mixed ceramic slurry.

[0050] Finally, a stainless steel crucible mold was used, and a copper mesh reinforcing layer with a thickness of 0.15 mm was placed inside the mold. The mixed ceramic slurry was quantitatively injected into the mold, and the oven temperature was controlled at 65℃ to dry and solidify. After demolding, a constant temperature of 42℃ and 55% humidity was applied for curing for 72 hours. Finally, it was placed in a calcining furnace, and the heating rate was controlled at 2℃ / min. The temperature was raised to 780℃ and held for 1.5 hours. The heating rate was controlled at 1.5℃ / min, and the temperature was raised to 1180℃ and held for calcination for 4.5 hours. Finally, the cooling rate was controlled at 2.5℃ / min. After cooling to room temperature, the crucible was removed to obtain the sintered crucible.

[0051] Example 2

[0052] A corrosion-resistant crucible for polycrystalline silicon ingot casting includes a heat dissipation base 2 and a copper mesh reinforcing layer with a thickness of 0.15 mm that fits the outline of the crucible body 1 in the inner wall. The crucible body 1 is made of mixed ceramic slurry.

[0053] A ring-shaped cylindrical heat dissipation base 2 is fixedly connected to the bottom of the crucible, and a heat-conducting block 3 corresponding to the bottom of the heat dissipation base 2 is installed inside the heat dissipation base 2. The heat dissipation base 2 is provided with heat dissipation holes 201, and the heat-conducting block 3 is provided with grooves 301 that can increase the heat conduction contact area. Figure 1 As shown in the structure, the heat conduction fast 3 uses an aluminum heat sink.

[0054] The specific components of the mixed ceramic slurry are as follows: 100 parts silica, 28 parts thermally conductive filler, 10 parts zirconium oxide, 5 parts alumina, 1 part defoamer GPE50, 1.2 parts acrylamide monomer, 2 parts N,N-methylenebisacrylamide crosslinking agent, 0.8 parts coagulation catalyst triethanolamine, and 1.2 parts polyacrylic acid dispersant.

[0055] The base material of the high thermal conductivity filler has a thermal conductivity of not less than 151 W·m. -1 / K, and the absolute value of the coefficient of thermal expansion is less than 4.2×10 -6 / K graphite, and the substrate surface is coated with a metal lubricating film.

[0056] The preparation method of corrosion-resistant crucibles for polycrystalline silicon ingots, and the specific preparation method of highly thermally conductive fillers are as follows:

[0057] Step 1: First, weigh out the dry and clean graphite, grind it to a fine 150 mesh and sieve it for later use;

[0058] Step 2: Weigh out 2 mol of titanium dioxide sulfate and 4 mol of sodium hypophosphite for the metal lubrication film;

[0059] Step 3: Weigh the graphite from Step 1, control the solid-liquid ratio to 1:5, add it to water and mix and stir, then add titanium sulfate and sodium hypophosphite and mix well.

[0060] Step 4: Simultaneously add ethyl formate complexing agent (5% by weight of graphite) and boric acid buffer (3% by weight of graphite) to the mixture; and add ferric chloride catalyst (1.5% by weight of the thermally conductive filler substrate) to the mixture.

[0061] Step 5: Stir the mixture until no more bubbles are generated. Let it stand for 5 minutes to complete the titanium lubricating film coating. Filter to obtain filter material. After drying the filter material, it does not need to be ground. It is directly sieved through a 150-mesh sieve again. After removing the sieve residue, a uniformly sized, highly thermally conductive filler is obtained.

[0062] The preparation method of the mixed ceramic slurry is as follows:

[0063] Step 1: Grind silica, zirconium oxide and alumina separately in a ball mill at 800 r / min for 6 hours. Then dry the ball-milled powder for later use. Mix them in a roller mixer according to the required mass proportions.

[0064] Step 2: Weigh acrylamide monomer and N,N-methylenebisacrylamide crosslinking agent and dissolve them in deionized water to obtain a premixed solution;

[0065] Step 3: Next, add polyacrylic acid dispersant to a small amount of deionized water, then add the highly thermally conductive filler and the mixture from Step 1, then continue to add an appropriate amount of deionized water to dilute and control the solid content to 75%, and stir evenly to obtain a slurry;

[0066] Step 4: Add the premixed liquid to the slurry, adjust the pH to 6.5 with ammonia water, and then add the defoamer GPE50 and the coagulation catalyst triethanolamine to obtain a new mixed ceramic slurry.

[0067] Finally, a stainless steel crucible mold was used, and a copper mesh reinforcing layer with a thickness of 0.15 mm was placed inside the mold. The mixed ceramic slurry was quantitatively injected into the mold, and the oven temperature was controlled at 65℃ to dry and solidify. After demolding, a constant temperature of 42℃ and 55% humidity was applied for curing for 72 hours. Finally, it was placed in a calcining furnace, and the heating rate was controlled at 2℃ / min. The temperature was raised to 780℃ and held for 1.5 hours. The heating rate was controlled at 1.5℃ / min, and the temperature was raised to 1180℃ and held for calcination for 4.5 hours. Finally, the cooling rate was controlled at 2.5℃ / min. After cooling to room temperature, the crucible was removed to obtain the sintered crucible.

[0068] Comparative Example 1

[0069] The difference between this comparative example and Example 1 is that: in Comparative Example 1, graphite was directly used as a highly thermally conductive filler, and no metal lubricating film was applied, while all other conditions were the same.

[0070] Comparative Example 2

[0071] The difference between this comparative example and Example 1 is that only the highly thermally conductive filler is not added in Comparative Example 2, while all other conditions are the same.

[0072] Comparative Example 3

[0073] The difference between this comparative example and Example 1 is that only 10 parts of zirconium oxide were not added in Comparative Example 3, while all other conditions were the same.

[0074] Crucibles of equal specifications were prepared according to the preparation methods of Examples 1-2 and Comparative Examples 1-3, and their corrosion resistance was tested. Referring to existing industry standards, the performance indicators of the corrosion-resistant quartz ceramic crucibles are: bulk density ≥ 1.94 g / cm³. 3 Thermal conductivity ≥1.0 W·m -1 / K, room temperature flexural strength ≥25MPa, apparent porosity ≤9%, test data are as follows:

[0075] <![CDATA[Volume density (g / cm 3 )]]> <![CDATA[Thermal conductivity (W·m -1 / K)]]> Flexural strength (MPa) Apparent porosity (%) Example 1 2.76 2.93 41 5.52 Example 2 2.89 3.17 39 5.76 Comparative Example 1 2.32 2.98 26 14.91 Comparative Example 2 1.63 0.92 23 10.08 Comparative Example 3 1.81 2.13 19 11.62

[0076] The data in the table above shows that the added high thermal conductivity filler can effectively improve thermal conductivity, which is beneficial for rapid heat dissipation and improving ingot casting efficiency. However, with the increase of high thermal conductivity filler, more particle size gaps will be generated, which will lead to a slight increase in apparent porosity. The increased porosity leads to a corresponding decrease in flexural strength. However, with more mass of material in the same volume, the bulk density will increase with the increase in mass of material. If no metal lubricating film is plated, the apparent porosity will increase significantly, possibly because the lubricity of the substrate is poor, leaving larger gaps. However, compared to Example 1, no other mass of material was added, which caused the bulk density to decrease with the increase in apparent porosity and the flexural strength to decrease. While the thermal conductivity decreases significantly, the thermal conductivity remains relatively stable. Without the addition of highly thermally conductive fillers, the most noticeable effect is a significant reduction in thermal conductivity. Simultaneously, the reduction in particulate fillers lowers the bulk density and interparticle spacing, thus decreasing apparent porosity, but this results in a substantial decrease in flexural strength. Comparing with Comparative Example 3, it is evident that without the addition of zirconium oxide, apparent porosity and bulk density further decrease, leading to a significant reduction in flexural strength. Thermal conductivity also decreases further, but not as drastically as in Comparative Example 2. Considering that zirconium oxide is harder than graphite, and graphite itself has good thermal conductivity, a synergistic combination of the two is necessary to achieve both high thermal conductivity and flexural strength.

[0077] Therefore, considering that a highly thermally conductive filler can improve the mechanical strength of the crucible, and taking into account the above data, Example 1 or 2 can be preferred as the preparation method of the corrosion-resistant crucible.

[0078] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A corrosion-resistant crucible for multicrystalline silicon ingot casting, comprising a heat-dissipating base (2), characterized in that: The inner wall of the crucible body (1) is provided with at least one layer of strong rib net layer matched with the profile of the crucible, and the crucible body (1) is made of mixed ceramic new slurry; The mass fraction of the mixed ceramic new slurry specific components is: 80-100 parts of silicon dioxide, 20-28 parts of strong heat-conducting filler, 10-15 parts of zirconium oxide, 5-10 parts of aluminum oxide, 0.8-1.5 parts of defoaming agent, 0.6-1.2 parts of monomer, 1-2 parts of crosslinking agent, 0.5-1 part of coagulation catalyst, 0.5-1.2 parts of dispersing agent; the base material of the strong heat-conducting filler adopts a material with a thermal conductivity not less than 151 W·m -1 / K and an absolute value of thermal expansion coefficient less than 4.2×10 -6 / K; the strong muscle net layer adopts a copper net or aluminum net with a thickness of 0.05mm-0.25mm. The strong heat-conducting filler substrate is made of any one or more of carbon fibers, carbon nanotubes, graphene and graphite, and the surface of the substrate is plated with a metal lubricating film.

2. The corrosion-resistant crucible for polycrystalline silicon ingot casting according to claim 1, characterized by: The bottom of the crucible is fixedly connected with a heat dissipation base (2) in the shape of an annular cylinder, and a heat-conducting block (3) corresponding to the bottom of the heat dissipation base (2) is installed in the heat dissipation base (2), the heat dissipation base (2) is provided with heat dissipation holes (201), and the heat-conducting block (3) is provided with grooves (301) capable of increasing the heat-conducting contact area.

3. A method for producing a corrosion-resistant crucible for multicrystalline silicon ingot, for producing the corrosion-resistant crucible for multicrystalline silicon ingot according to any one of claims 1 to 2, characterized by: The preparation method of the strong heat-conducting filler is as follows: Step one: first, the dry and clean strong heat-conducting filler substrate is weighed and ground to 150-600 mesh for use; Step two: the metal lubricating film is prepared by weighing the plating film salt compound and sodium hypophosphite with a molar mass ratio of 1:2; Step three: the strong heat-conducting filler substrate in step one is weighed, the solid-liquid ratio is controlled to be 1:5-10, and it is mixed and stirred in water, and a sufficient amount of plating film salt compound and sodium hypophosphite is added and mixed; Step four: 5-8% of ethyl formate complexing agent and 3-5% of boric acid buffer agent are synchronously added to the mixed solution, and 0.8-2.5% of the catalyst ferric chloride is also added to the mixed solution; Step five: the mixed solution is stirred, and when no bubbles are generated in the mixed solution, the metal lubricating film is plated after standing for 3-8 min, and the filter material is obtained by filtration; then the filter material is dried without grinding, and is directly sieved again through a 150-600 mesh sieve, and the strong heat-conducting filler with uniform particle size is obtained after the sieve residue is removed.

4. The method of producing a corrosion-resistant crucible for polycrystalline silicon ingot according to claim 3, characterized by: The plating film salt compound is any one of titanium sulfate, tungsten disulfide, chromium sulfate and nickel sulfate.

5. The method of producing a corrosion-resistant crucible for polycrystalline silicon ingot according to claim 4, characterized by: The preparation method of the mixed ceramic new slurry is as follows: Step one: the silicon dioxide, zirconium oxide and aluminum oxide are respectively ball milled at 800-1200 r / min for 4.5-8 h by a ball mill, and then the powder after ball milling is dried for use, and the mixed material is mixed by a roller stirring mixer according to the required mass fraction; Step two: 0.6-1.2 parts of acrylamide or methacrylamide monomer and 1-2 parts of N,N-methylene bisacrylamide crosslinking agent are dissolved in deionized water to obtain a premix solution; Step three: 0.5-1.2 parts of a dispersing agent is added to a small amount of deionized water, and then 20-28 parts of the strong heat-conducting filler and the mixed material in step one are added, and then an appropriate amount of deionized water is added for dilution and the solid content is controlled to be 75-85%, and the slurry is uniformly stirred to obtain a slurry; Step four: the premix solution is mixed into the slurry, the pH is adjusted to 6-8 by using ammonia water, and then 0.8-1.5 parts of a defoaming agent and 0.5-1 part of a coagulation catalyst are added to obtain the mixed ceramic new slurry.

6. The method of producing a corrosion-resistant crucible for polycrystalline silicon ingot according to claim 5, wherein: The specific steps are as follows: the mixed ceramic new material slurry is quantitatively injected into a stainless steel crucible mold, the oven temperature is controlled to be 40-80 DEG C for drying and curing forming, after demolding, a curing environment with constant temperature of 38-45 DEG C and humidity of 45-55% is applied, the curing is not less than 72 h, finally, the temperature rising rate is controlled to be 2-2.5 DEG C / min, the temperature is raised to 780-850 DEG C, the temperature is kept for 0.5-1.5 h, the temperature rising rate is controlled to be 1-1.5 DEG C / min, the temperature is raised to 1180-1250 DEG C, the temperature is kept for calcination for 2-4.5 h, finally, the temperature falling rate is controlled to be 1.5-3 DEG C / min, the temperature is lowered to room temperature, and then the sintered crucible is taken out.

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