Method for producing hot zone products and hot zone of a single crystal furnace

Abstract

The application discloses a hot field product preparation method and a single crystal furnace hot field, and relates to the technical field of single crystal furnace hot field products. The hot field product preparation method comprises the following steps: preparing a carbon-carbon base body by using a carbon-carbon composite material; preparing a infiltrated powder, wherein the infiltrated powder comprises silicon powder; locally coating the carbon-carbon base body with the infiltrated powder and performing reaction infiltration to locally form a corrosion-resistant layer on the carbon-carbon base body, so that a hot field product is obtained, wherein the material of the corrosion-resistant layer comprises silicon carbide. In the embodiment of the application, the corrosion-resistant layer is locally formed on the carbon-carbon base body, and the silicon carbide in the corrosion-resistant layer has the characteristic of corrosion resistance, so that the finally-prepared hot field product has the characteristic of corrosion resistance, the hot field product is prevented from being corroded by silicon vapor, and the service life of the hot field product is improved.

Description

Technical Field

[0001] This invention relates to the field of crystal growth and manufacturing technology, and in particular to a method for preparing a hot zone product and a hot zone for a single crystal furnace. Background Technology

[0002] Currently, the Czochralski method is mainly used to produce monocrystalline silicon in a single-crystal furnace. A single-crystal furnace includes a hot zone, which comprises a heat shield, a quartz crucible, crucible sides, a heater, and an insulation cylinder. The heat shield and crucible sides are typically made of carbon-carbon composite materials.

[0003] A large amount of silicon vapor exists in the hot zone. During the production of monocrystalline silicon, the heat shield and crucible sides are easily corroded by silicon vapor, resulting in a low service life of the heat shield and crucible sides. Summary of the Invention

[0004] This invention provides a method for preparing a hot zone product and a hot zone for a single crystal furnace, aiming to solve the technical problem that the heat shield and crucible sides are easily corroded by silicon vapor in the prior art.

[0005] In a first aspect, embodiments of the present invention provide a method for preparing a thermal field product, comprising:

[0006] Carbon-carbon matrix is ​​prepared using carbon-carbon composite materials;

[0007] Prepare melt-infiltrating powder, wherein the melt-infiltrating powder includes silicon powder;

[0008] The carbon-carbon matrix is ​​partially coated with the melt-infiltrating powder and reactive melt-infiltrating is performed to locally form a corrosion-resistant layer on the carbon-carbon matrix, thereby obtaining the thermal field product, wherein the material of the corrosion-resistant layer includes silicon carbide.

[0009] Optionally, the thermal field product includes a thermal screen, and the carbon-carbon matrix includes a thermal screen carbon-carbon matrix;

[0010] The preparation of a carbon-carbon matrix using carbon-carbon composite materials includes: preparing a carbon-carbon matrix for a heat shield using carbon-carbon composite materials;

[0011] The process of partially coating the carbon-carbon matrix with the melt-infiltrating powder and performing reactive melt-infiltrating to locally form a corrosion-resistant layer on the carbon-carbon matrix, thereby obtaining the thermal field product, includes:

[0012] The heat shield is obtained by using a heat shield container to coat the bottom section of the heat shield carbon-carbon matrix with the melt-infiltrating powder and then performing reactive melt-infiltrating to form a heat shield corrosion-resistant layer on the bottom section of the heat shield carbon-carbon matrix.

[0013] Optionally, the step of coating the bottom section of the heat shield carbon matrix with the melt-infiltrating powder using a heat shield receiving fixture includes:

[0014] Prepare a heat shield receiving fixture corresponding to the heat shield carbon-carbon substrate, wherein the height of the heat shield receiving fixture is lower than the height of the heat shield carbon-carbon substrate;

[0015] The bottom section of the carbon-carbon substrate of the heat shield is placed inside the heat shield housing fixture;

[0016] The melt-infiltrating powder is filled between the heat shield receiving fixture and the heat shield carbon-carbon matrix, so that the melt-infiltrating powder covers the bottom section of the heat shield carbon-carbon matrix, wherein the filling thickness of the melt-infiltrating powder is 1mm-30mm.

[0017] Optionally, the hot zone product further includes a crucible side, and the carbon-carbon matrix includes a crucible side carbon-carbon matrix;

[0018] The preparation of a carbon-carbon matrix using carbon-carbon composite materials includes: preparing a crucible side carbon-carbon matrix using carbon-carbon composite materials;

[0019] The process of partially coating the carbon-carbon matrix with the melt-infiltrating powder and performing reactive melt-infiltrating to locally form a corrosion-resistant layer on the carbon-carbon matrix, thereby obtaining the thermal field product, includes:

[0020] The crucible side is obtained by using a crucible side receiving fixture to coat the top section of the crucible side carbon-carbon matrix with the melt-infiltrating powder and then performing reactive melt-infiltrating to form a crucible side corrosion-resistant layer on the top section of the crucible side carbon-carbon matrix.

[0021] Optionally, the step of using a crucible side receiving fixture to coat the top section of the crucible side carbon-carbon matrix with the melt-infiltrating powder includes:

[0022] Prepare a crucible side receiving fixture corresponding to the crucible side carbon-carbon matrix, wherein the height of the crucible side receiving fixture is lower than the height of the crucible side carbon-carbon matrix;

[0023] The top section of the crucible side carbon-carbon matrix is ​​placed inside the crucible side receiving fixture;

[0024] The melt-infiltrating powder is filled between the crucible side receiving fixture and the crucible side carbon-carbon matrix, so that the melt-infiltrating powder covers the top section of the crucible side carbon-carbon matrix, wherein the filling thickness of the melt-infiltrating powder is 1mm-30mm.

[0025] Optionally, the infiltrated powder further includes carbon powder and / or silicon carbide powder, wherein the silicon powder accounts for 50%-100% by mass, the carbon powder accounts for 0%-50% by mass, and the silicon carbide powder accounts for 0%-10% by mass.

[0026] Optionally, the silicon powder accounts for 50%-85% of the mass, and the carbon powder accounts for 0%-15% of the mass.

[0027] Optionally, the infiltrated powder further includes alumina powder, wherein the alumina powder accounts for 0%-6% of the total mass.

[0028] Optionally, the reactive melting process includes:

[0029] The heat shield container, which contains the carbon-carbon substrate and is filled with the melt-infiltrating powder, is placed in a reaction melt-infiltrating furnace and reacted and melt-infiltrated under inert gas protection at a temperature of 1500℃-2200℃.

[0030] And / or, the crucible side container, which has the crucible side carbon-carbon matrix and is filled with the melting powder, is placed in a reaction melting furnace and the reaction melting is carried out under inert gas protection and at a temperature of 1500℃-2200℃.

[0031] Optionally, the hot screen receiving fixture includes a first receiving cavity with a depth of 120mm-130mm, and the crucible side receiving fixture includes a fixture body, a second receiving cavity, and a second boss, wherein the maximum depth formed by the second receiving cavity and the fixture body or the second boss is 110mm-300mm.

[0032] Placing the bottom section of the carbon-carbon substrate of the heat shield within the heat shield housing fixture includes:

[0033] The bottom section of the heat shield carbon-carbon substrate is placed in the first receiving cavity of the heat shield receiving fixture;

[0034] Placing the top section of the crucible side carbon-carbon matrix within the crucible side receiving fixture includes:

[0035] The top section of the crucible side carbon matrix is ​​placed in the second receiving cavity of the crucible side receiving fixture.

[0036] Optionally, the preparation of the melt-infiltrated powder includes:

[0037] Silicon powder, carbon powder, silicon carbide powder and alumina powder are prepared, and the silicon powder, carbon powder, silicon carbide powder and alumina powder are mixed evenly to obtain melt-infiltrated powder.

[0038] Optionally, the preparation of the carbon-carbon matrix using carbon-carbon composite materials includes:

[0039] Carbon fiber preforms are prepared using carbon fiber.

[0040] The carbon fiber preform was densified using chemical vapor deposition to obtain a carbon-carbon composite material.

[0041] The carbon-carbon composite material is subjected to graphitization treatment;

[0042] The graphitized carbon-carbon composite material is processed according to the processing dimensions of the aforementioned thermal field product to obtain an intermediate matrix;

[0043] Pyrolytic carbon is deposited on the surface of the intermediate matrix using chemical vapor deposition to obtain a carbon-carbon matrix.

[0044] Secondly, embodiments of the present invention provide a single-crystal furnace hot zone, including a hot zone product prepared using any of the hot zone product preparation methods described above.

[0045] In this embodiment of the invention, a corrosion-resistant layer is locally formed on the carbon-carbon substrate. The silicon carbide in the corrosion-resistant layer has corrosion-resistant properties, thereby giving the final thermal field product corrosion resistance and preventing it from being corroded by silicon vapor, thus extending its service life. Since the corrosion-resistant layer is only locally formed on the carbon-carbon substrate, compared to forming a corrosion-resistant layer on the entire surface of the carbon-carbon substrate, the material cost in the manufacturing process is reduced, thereby reducing the manufacturing cost of the thermal field product. Furthermore, the increased service life of the thermal field product reduces the frequency of replacement, thus reducing the maintenance cost of the single-crystal furnace thermal field. In addition, the locally formed corrosion-resistant layer scheme does not cause an excessive increase in the weight of the final thermal field product compared to a full coating.

[0046] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other objects, features and advantages of the present invention more obvious and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of a half-section of the thermal field of a single-crystal furnace in the prior art.

[0048] Figure 2 This is a schematic diagram of the failure process of a carbon-carbon thermal shield in the prior art;

[0049] Figure 3 This is a schematic diagram of the failure process of carbon crucible sides in the prior art;

[0050] Figure 4 A flowchart illustrating the steps of a method for preparing a thermal field product according to an embodiment of the present invention;

[0051] Figure 5 This is a cross-sectional view of the heat shield accommodating fixture provided in an embodiment of the present invention;

[0052] Figure 6 This is a cross-sectional view of the crucible side accommodating fixture provided in an embodiment of the present invention;

[0053] Figure 7This is a schematic diagram of the crucible side structure in the hot zone of a single crystal furnace provided in an embodiment of the present invention;

[0054] Figure 8 A schematic diagram of the layer structure of the crucible side modification section in the crucible side of the hot zone of a single crystal furnace provided for an embodiment of the invention;

[0055] Figure 9 This is a partial structural schematic diagram of the heat shield in the hot zone of a single crystal furnace provided for an embodiment of the invention.

[0056] Figure 10 A schematic diagram of the layer structure of the heat shield modification section in the heat shield of the single crystal furnace hot zone provided for an embodiment of the invention;

[0057] Figure 11 The infrared emissivity spectrum of the crucible before the overall coating;

[0058] Figure 12 The infrared emissivity spectrum of the crucible after overall coating.

[0059] Figure label:

[0060] 1-Crystal rod, 2-Silicon liquid, 3-Carbon-carbon heat shield, 4-Upper insulation cylinder, 5-Main heater, 6-Quartz crucible, 7-Lower insulation cylinder, 8-Carbon-carbon crucible side, 9-Bottom heater, 10-Heat shield housing fixture, 11-First housing cavity, 111-First sidewall, 112-First bottom wall, 12-First boss, 20-Carbon-carbon heat shield substrate, 30-Crucible side housing fixture, 31-Second housing cavity, 311-Second sidewall, 312 - Second bottom wall, 32- Second boss, 33- Tooling body, 40- Carbon-carbon matrix of crucible side, 50- Crucible side, 51- Modified section of crucible side, 511- Substrate layer of crucible side, 512- Corrosion-resistant layer of crucible side, 5121- First outer coating, 5122- First modified layer, 60- Heat shield, 61- Modified section of heat shield, 611- Substrate layer of heat shield, 612- Corrosion-resistant layer of heat shield, 6121- Second outer coating, 6122- Second modified layer. Detailed Implementation

[0061] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0062] Reference Figure 1The single-crystal furnace hot zone includes a quartz crucible 6, a carbon-carbon crucible support 8, a carbon-carbon heat shield 3 above the carbon-carbon crucible support 8, an upper heat insulation cylinder 4, a lower heat insulation cylinder 7, a main heater 5, and a bottom heater 9. The quartz crucible 6 contains molten silicon 2, in which crystal pulling, shoulder formation, and equal diameter determination are performed to obtain the crystal rod 1. The single-crystal furnace hot zone is a crucial factor affecting the quality and cost of crystal pulling. Both the carbon-carbon crucible support 8 and the carbon-carbon heat shield 3 are made of carbon-carbon composite materials. Carbon-carbon composite materials can withstand temperatures up to 2500℃ without deformation, and also have low density and are easy to mold.

[0063] In the hot zone of a single crystal furnace, the carbon-carbon crucible side 8 and the carbon-carbon hot screen 3 are most susceptible to corrosion by silicon vapor, which leads to their failure. After failure, new carbon-carbon crucible side 8 and carbon-carbon hot screen 3 need to be replaced, resulting in high maintenance costs for the hot zone of the single crystal furnace.

[0064] Reference Figure 1 and Figure 2 During use, because the carbon-carbon heat shield 3 is located above the molten silicon 2, the silicon vapor from the evaporating molten silicon 2 continuously erodes the bottom of the carbon-carbon heat shield 3, causing silicon carbide to gradually form on the bottom. Due to the difference in thermal expansion coefficients between silicon carbide and the carbon-carbon composite material, the eroded silicon carbide gradually peels off, and the bottom arc of the carbon-carbon heat shield 3 becomes pitted and uneven, its thickness continuously decreasing until it is eventually corroded through, reaching its service life limit. During this process, the corroded silicon carbide and carbon-carbon composite material are very likely to fall into the molten silicon 2, thus affecting the quality of the final crystal rod 1. It should be noted that during the failure process of the carbon-carbon heat shield 3, the straight wall section of the carbon-carbon heat shield 3, because it is far from the molten silicon 2, is not corroded by silicon vapor, and therefore the straight wall section remains intact and will not fail.

[0065] Reference Figure 1 and Figure 3 The top of the carbon-carbon crucible side 8 is close to the main heater 5, and its temperature is highest during the crystal pulling process. The rate of silicon vapor corrosion is related to temperature and silicon vapor concentration. Due to its high temperature, the top of the carbon-carbon crucible side 8 reacts violently with silicon vapor. As the number of furnaces used increases, the top of the carbon-carbon crucible side 8 is continuously corroded and thinned, eventually leading to the failure of the carbon-carbon crucible side 8.

[0066] Firstly, referring to Figure 4 This invention discloses a method for preparing a thermal field product, comprising:

[0067] Step 101: Prepare a carbon-carbon matrix using carbon-carbon composite materials.

[0068] Specifically, the carbon-carbon matrix is ​​the main component of the heating element product, and the material of the carbon-carbon matrix is ​​a carbon-carbon composite material. Different heating element products correspond to different shapes and sizes of carbon-carbon matrices. The heating element product may include a heat shield 60 and a crucible side 50. When preparing the heat shield 60, step 101 specifically involves preparing the heat shield carbon-carbon matrix 20 using a carbon-carbon composite material. When preparing the crucible side 50, step 101 specifically involves preparing the crucible side carbon-carbon matrix 40 using a carbon-carbon composite material.

[0069] Step 102: Prepare melt-infiltrated powder.

[0070] Specifically, the infiltrated powder includes silicon powder, which can be high-purity silicon powder with a particle size of 0.5um-200um and a purity greater than 99.9%.

[0071] Step 103: The carbon-carbon matrix is ​​locally coated with melt-infiltrating powder and reactive melt-infiltrating is carried out to form a corrosion-resistant layer locally on the carbon-carbon matrix, thereby obtaining the thermal field product.

[0072] Specifically, when preparing the heat shield 60, since the bottom section of the heat shield is susceptible to corrosion by silicon vapor, a melt-infiltrating powder can be used to locally coat the bottom section of the carbon-carbon matrix 20 of the heat shield. When preparing the crucible side 50, since the top section of the crucible side is susceptible to corrosion by silicon vapor, a melt-infiltrating powder can be used to locally coat the top section of the carbon-carbon matrix 40 of the crucible side. (Refer to...) Figure 5 The bottom section of the carbon substrate 20 of the heatsink includes an arc segment, as shown in the reference. Figure 6 The top section of the carbon matrix 40 of the crucible side is away from the arc-shaped part on it.

[0073] After locally coating a carbon-carbon matrix with melt-infiltrating powder, reactive melt-infiltrating can be carried out under high temperature and inert gas protection. This allows the melt-infiltrating powder to melt into a liquid state and penetrate into the carbon-carbon matrix, thereby locally forming a corrosion-resistant layer on the carbon-carbon matrix, resulting in a thermally conductive product. During the reactive melt-infiltrating process, the silicon powder in the melt-infiltrating powder reacts with the carbon-carbon matrix to generate silicon carbide, thus making the corrosion-resistant layer composed of silicon carbide.

[0074] In the single crystal pulling process, the temperature field inside the single crystal furnace has a significant impact on the crystallization rate. In existing technologies, the thermal field inside the single crystal furnace is primarily composed of carbon-carbon materials, which have a thermal conductivity of 15–35 W / (m·K), while coating materials, such as silicon carbide coatings, have a thermal conductivity of 80–100 W / (m·K). In a specific embodiment, such as… Figure 1 As shown, Figure 1 The heat generated by the heater is mainly transferred to the crucible sides through thermal radiation. Figure 11-12The infrared emissivity spectra before and after the overall coating (silicon carbide coating) of the crucible side are obtained using a Fourier transform infrared spectrometer. As shown in the figure, the emissivity after the overall coating is significantly lower than that before the coating, indicating that the overall coating reduces the thermal radiation efficiency of the crucible side, which is detrimental to heat transfer in the single crystal furnace. In a specific embodiment, the purpose of the heat shield in the thermal field is to establish a temperature gradient along the vertical direction of the crystal. The part above the heat shield is crystalline silicon, which requires a lower temperature, while the part below the heat shield is liquid silicon, which needs to reach at least the melting point of silicon. The heat transfer inside the heat shield is mainly by conduction; therefore, the thermal conductivity of the heat shield material should not be too high in order to establish a temperature gradient.

[0075] Furthermore, the coating increases the modified density of the thermal field, thereby increasing its weight. In one specific embodiment, the crucible side is mounted on a slender, round rod during operation, which is driven to rotate by the motor torque. In this condition, the stability of the rod is affected by two factors. First, the rotational torque generated by the rotation of the rod's supporting portion is influenced by the moment of inertia of that portion; the greater the moment of inertia, the greater the torque, resulting in a higher mechanical load on the system and a greater likelihood of mechanical imbalance. The overall modified coating on the crucible side approximately doubles its mass, increasing its moment of inertia and raising the risk of thermal field mechanical imbalance. Second, the stability of the rod is affected by the pressure of the supporting portion. The increased weight of the crucible side leads to excessive pressure, increasing the risk of rod instability and potentially causing the molten silicon, crucible, and crucible side in the supporting portion to tilt, resulting in a silicon leakage production accident. In another specific embodiment, the heat shield is assembled in the hot zone of a single crystal furnace using a graphite bolt connection structure. Due to the heat shield's own weight, the graphite bolts frequently break, causing the heat shield to fall into the quartz crucible and resulting in a production accident. The density of a carbon-carbon heat shield is approximately 0.8–1.45 g / cm³, while the density after full coating modification is 1.8–2.6 g / cm³. This more than doubles the weight of the heat shield, significantly increasing the risk of it falling.

[0076] To address this, a method of locally preparing a corrosion-resistant layer is adopted, that is, using a locally modified coating thermal field structure to ensure that the material can resist silicon vapor corrosion while minimizing the impact of the material coating on the temperature field risk and the risk caused by increased weight. In this embodiment of the invention, a corrosion-resistant layer is locally formed on the carbon-carbon substrate. The silicon carbide in the corrosion-resistant layer has corrosion-resistant properties, thereby giving the final thermal field product corrosion resistance, preventing the thermal field product from being corroded by silicon vapor, and thus improving the service life of the thermal field product. In addition, since the corrosion-resistant layer is only locally formed on the carbon-carbon substrate, compared to forming a corrosion-resistant layer on the entire surface of the carbon-carbon substrate, the material cost in the preparation process is reduced, thereby reducing the preparation cost of the thermal field product. Furthermore, since the service life of the thermal field product is improved, the replacement frequency of the thermal field product is reduced, thereby reducing the maintenance cost of the single crystal furnace thermal field.

[0077] The thermal field products include thermal screen 60, and the carbon-carbon matrix includes thermal screen carbon-carbon matrix 20.

[0078] When preparing the heat shield 60 in the heat field product, step 101 uses carbon-carbon composite material to prepare carbon-carbon matrix, including: preparing carbon-carbon matrix 20 of heat shield using carbon-carbon composite material.

[0079] Step 103 involves partially coating a carbon-carbon matrix with melt-infiltrating powder and performing reactive melt-infiltrating to form a corrosion-resistant layer on the carbon-carbon matrix, thereby obtaining a thermal field product. This includes: coating the bottom section of the carbon-carbon matrix of the thermal screen with melt-infiltrating powder using a thermal screen container and performing reactive melt-infiltrating to form a corrosion-resistant layer on the bottom section of the carbon-carbon matrix of the thermal screen, thereby obtaining a thermal screen.

[0080] Specifically, since the bottom section of the heat shield is susceptible to corrosion by silicon vapor, the heat shield housing fixture 10 can be used to partially coat the bottom section of the heat shield carbon-carbon substrate 20 with melt-infiltrating powder. The height of the bottom section of the heat shield carbon-carbon substrate 20 is 110mm-120mm.

[0081] The final prepared heat shield 60 is as follows Figure 9 As shown, the heat shield 60 includes a heat shield modification section 61, and the heat shield 60 also has an arc segment. The height H4 of the heat shield modification section 61 is greater than the radius of the arc segment, and H4 is 110mm-120mm. (Refer to...) Figure 10 The heat shield 60 has an internal cavity. The heat shield modification section 61 includes a heat shield substrate layer 611 near the internal cavity and a heat shield corrosion-resistant layer 612 away from the internal cavity. The heat shield corrosion-resistant layer 612 is formed after reaction melting and infiltration in the above method. The thickness of the heat shield corrosion-resistant layer 612 is greater than 2 mm. The density of the heat shield modification section 61 is 1.8 g / cm³. 3 -2.6g / cm 3The flexural strength of the heat shield modified section 61 is 110MPa-210MPa, and the purity of non-silicon impurities in the heat shield modified section 61 is <1000ppm.

[0082] The heat shield corrosion-resistant layer 612 specifically includes a second modified layer 6122 connected to the heat shield substrate layer 611 and a second outer coating layer 6121 connected to the second modified layer 6122. The second modified layer 6122 is located between the second outer coating layer 6121 and the heat shield substrate layer 611. The heat shield substrate layer 611 is made of carbon-carbon composite material. The second outer coating layer 6121 is made of silicon carbide and silicon, with silicon carbide accounting for 50%-99% of the mass and silicon accounting for 0%-15%. The second modified layer 6122 is made of silicon carbide, carbon-carbon composite material, and silicon, with silicon carbide accounting for 10%-50% of the mass, carbon-carbon composite material accounting for 20%-95% of the mass, and silicon accounting for 0%-15%.

[0083] In this embodiment of the invention, addressing the issue that the bottom section of the heat shield in the prior art is susceptible to corrosion by silicon vapor, a corrosion-resistant layer is formed on the bottom section of the carbon-carbon substrate during the fabrication of the heat shield 60 in the thermal field product. This imbues the bottom section of the prepared heat shield 60 with corrosion resistance, eliminating the need to focus on the straight-wall section, which is less susceptible to silicon vapor corrosion, thereby reducing the fabrication cost of the heat shield 60. In this embodiment of the invention, the service life of the heat shield 60 prepared by the above method is extended by approximately 12 months compared to the service life of a heat shield using only carbon-carbon composite materials. Furthermore, for the heat shield, the method of locally fabricating the corrosion-resistant layer does not affect the temperature gradient within the single crystal furnace compared to a uniform coating; and the method of locally fabricating the corrosion-resistant layer does not cause excessive weight increase to the heat shield, thus avoiding the risk of the heat shield potentially falling off.

[0084] The aforementioned bottom section, in which the melt-infiltrating powder is partially coated onto the carbon-carbon matrix of the heat shield using a heat shield containing fixture, includes:

[0085] Prepare a heat shield container corresponding to the heat shield carbon-carbon matrix; place the bottom section of the heat shield carbon-carbon matrix inside the heat shield container; fill the space between the heat shield container and the heat shield carbon-carbon matrix with melt-infiltrating powder so that the melt-infiltrating powder covers the bottom section of the heat shield carbon-carbon matrix.

[0086] Specifically, the heat shield container fixture 10, such as Figure 5As shown. The height of the heat shield housing fixture 10 is lower than the height of the heat shield carbon-carbon substrate 20. The filling thickness of the melt-infiltrated powder is 1mm-30mm, specifically 1mm, 2mm, 5mm, 10mm, 15mm, 20mm, 25mm, 30mm, etc. When the filling thickness of the melt-infiltrated powder is 1mm-30mm, the thickness of the corrosion-resistant layer in the final prepared heat field product is greater than 2mm. The greater the thickness of the corrosion-resistant layer in the final prepared heat field product, the better the corrosion resistance of the heat field product. The thickness of the corrosion-resistant layer in the final prepared heat field product is less than or equal to the thickness of the heat field product itself. The thickness of the heat shield itself is 9mm-12mm, and the thickness of the crucible side itself is 15mm-20mm. Therefore, the thickness of the corrosion-resistant layer in the final prepared heat shield is 2mm-12mm, and the thickness of the corrosion-resistant layer in the final prepared crucible side is 2mm-20mm.

[0087] When the silicon powder in the melt-infiltrating powder melts at high temperatures, part of it reacts with the carbon powder, and part penetrates into the carbon-carbon matrix. When the filling thickness of the melt-infiltrating powder is less than 1 mm, most of the melted silicon powder reacts with the carbon powder in the melt-infiltrating powder, with only a very small amount penetrating into the carbon-carbon matrix, and the penetration depth is less than 1 mm. This results in the formed corrosion-resistant layer adhering to the surface of the hot-field product, with low bonding strength and easy detachment. When the filling thickness of the melt-infiltrating powder is greater than 30 mm, the melt-infiltrating powder penetrates from the surface of the hot-field product to the other side. The carbon-carbon matrix is ​​100% modified along the thickness direction, and a large amount of melt-infiltrating powder cannot be absorbed and utilized. This leads to a waste of melt-infiltrating powder material, and the excess melt-infiltrating powder, after being melted and solidified at high temperatures, adheres to the outer wall of the hot-field product, resulting in an excessively thick corrosion-resistant layer. This can even significantly alter the original dimensions and surface roughness of the hot-field product, requiring secondary polishing, which damages the corrosion-resistant layer and affects the performance of the modified hot-field product to some extent. In this embodiment of the invention, the filling thickness of the melt-infiltrating powder is 1mm-30mm, which can ensure the thickness of the corrosion-resistant layer in the prepared hot field product, thereby ensuring the corrosion resistance of the corrosion-resistant layer, while avoiding the waste of melt-infiltrating powder material and avoiding secondary grinding.

[0088] The effects and appearances of the thermal field products prepared under different filling thicknesses of the melt-infiltrating powder and different proportions of various materials in the melt-infiltrating powder are shown in Table 1.

[0089] Table 1

[0090]

[0091]

[0092] Table 1 shows that the strength of the existing thermal field product without a corrosion-resistant layer is A, and its density is B. The strength of the thermal field product can be measured using a strength measuring instrument; specifically, it can be considered as flexural strength. The density of the thermal field product is calculated based on its mass and volume. The density of the thermal field product is the ratio of its mass to its volume. When the volume of the thermal field product remains constant, the greater its mass, the greater its density.

[0093] In Comparative Example 1, the filling thickness of the melt-infiltrating powder is less than 1 mm. The resulting corrosion-resistant layer adheres to the surface of the hot-field product, exhibiting low bonding strength and easy detachment. The strength and density of the prepared hot-field product remain essentially unchanged. In Comparative Examples 2 to 4, the filling thickness of the melt-infiltrating powder is greater than 30 mm. While the strength and density of the prepared hot-field product are enhanced, the excess melt-infiltrating powder, after melting and solidifying at high temperatures, adheres to the outer wall of the hot-field product, resulting in an excessively thick corrosion-resistant layer. This can even significantly alter the original dimensions and surface roughness of the hot-field product.

[0094] The preferred filling thickness of the melt-infiltrating powder is 2mm-20mm. As shown in Table 1, in Examples 4 to 6, the filling thickness of the melt-infiltrating powder is 2mm. The difference between Examples 5 and 6 and Example 4 is that the ratio of the melt-infiltrating powder is different. In Examples 7 to 9, the filling thickness of the melt-infiltrating powder is 20mm. The difference between Examples 8 and 9 and Example 7 is that the ratio of the melt-infiltrating powder is different.

[0095] Table 1 shows that when the filling thickness of the melt-infiltrating powder is 2 mm, the strength of the prepared hot-field product increases by approximately 2%-11%, and the density increases by approximately 5%-16%. When the filling thickness of the melt-infiltrating powder is 20 mm, the strength of the prepared hot-field product increases by approximately 12%-84%, and the density increases by approximately 28%-48%. The optimal filling thickness of the melt-infiltrating powder is 20 mm.

[0096] When placing the bottom section of the heat shield carbon-carbon substrate 20 inside the heat shield housing fixture 10, a gap of 1mm-30mm must be maintained between the outer surface of the bottom section of the heat shield carbon-carbon substrate 20 and the heat shield housing fixture 10 to facilitate the filling of the melt-infiltrating powder. Specifically, the melt-infiltrating powder is filled between the outer surface of the bottom section of the heat shield carbon-carbon substrate 20 and the heat shield housing fixture 10, so that the melt-infiltrating powder covers the outer surface of the bottom section of the heat shield carbon-carbon substrate 20. It should be noted that the bottom of the heat shield carbon-carbon substrate 20 has a bottom opening, and a bottom protrusion is provided around the perimeter of the bottom opening; the bottom section of the heat shield carbon-carbon substrate 20 does not include this bottom protrusion.

[0097] In this embodiment of the invention, the heat shield receiving fixture 10 facilitates the coating of the melt-infiltrating powder onto the bottom section of the heat shield carbon substrate 20 according to the required thickness, thereby ensuring the uniformity of the thickness of the melt-infiltrating powder.

[0098] The hot zone products also include the crucible side 50, and the carbon-carbon matrix includes the crucible side carbon-carbon matrix 40.

[0099] Step 101 involves preparing a carbon-carbon matrix using carbon-carbon composite materials, including: preparing a crucible side carbon-carbon matrix using carbon-carbon composite materials.

[0100] Step 103 involves partially coating a carbon-carbon matrix with melt-infiltrating powder and performing reactive melt-infiltrating to form a corrosion-resistant layer on the carbon-carbon matrix, thereby obtaining a hot zone product. This includes: coating the top section of the crucible side carbon-carbon matrix with melt-infiltrating powder using a crucible side accommodating fixture and performing reactive melt-infiltrating to form a crucible side corrosion-resistant layer on the top section of the crucible side carbon-carbon matrix, thereby obtaining the crucible side.

[0101] Specifically, since the top section of the crucible side 50 is susceptible to corrosion by silicon vapor, the crucible side receiving fixture 30 can be used to partially coat the top section of the crucible side carbon-carbon matrix 40 with melt-infiltrating powder. The height of the top section of the crucible side carbon-carbon matrix 40 is 100mm-200mm.

[0102] The final prepared crucible side 50 is as follows Figure 7 As shown, the crucible side 50 includes a crucible side modification section 51, and the height H3 of the crucible side modification section 51 is 100mm-200mm. (Refer to...) Figure 8 The crucible side 50 has a crucible mounting cavity. The crucible side modification section 51 includes a crucible side substrate layer 511 and a crucible side corrosion-resistant layer 512 connected to the crucible side substrate layer 511. The crucible side corrosion-resistant layer 512 is located away from and / or close to the crucible mounting cavity. The crucible side corrosion-resistant layer 512 is formed after reaction melting and infiltration in the above method. The crucible side modification section 51 may include a crucible side corrosion-resistant layer 512 located away from the crucible mounting cavity; or, the crucible side modification section 51 may include a crucible side corrosion-resistant layer 512 located close to the crucible mounting cavity; or, the crucible side modification section 51 may include crucible side corrosion-resistant layers 512 located both away from and close to the crucible mounting cavity. That is to say, the crucible side corrosion-resistant layer 512 of the crucible side modification section 51 may be disposed on the inner side, the outer side, or both sides of the crucible mounting cavity. When the corrosion-resistant layer 512 of the crucible side is far from the crucible mounting cavity, the substrate layer 511 of the crucible side is close to the crucible mounting cavity; when the corrosion-resistant layer 512 of the crucible side is close to the crucible mounting cavity, the substrate layer 511 of the crucible side is far from the crucible mounting cavity; when the corrosion-resistant layer 512 of the crucible side is either far from or close to the crucible mounting cavity, that is, when the corrosion-resistant layer 512 of the crucible side is located on both the inner and outer sides, the substrate layer 511 of the crucible side is located in the middle of the corrosion-resistant layer 512 of the crucible side on both the inner and outer sides. The thickness of the corrosion-resistant layer 512 of the crucible side is greater than 2 mm. The density of the modified section 51 of the crucible side is 1.8 g / cm³. 3 -2.6g / cm 3 The bending strength of the crucible side modification section 51 is 110MPa-210MPa, and the purity of non-silicon impurities in the crucible side modification section 51 is <1000ppm.

[0103] The crucible side corrosion-resistant layer 512 specifically includes a first modified layer 5122 connected to the crucible side substrate layer 511 and a first outer coating layer 5121 connected to the first modified layer 5122. The first modified layer 5122 is located between the first outer coating layer 5121 and the crucible side substrate layer 511. The crucible side substrate layer 511 is made of carbon-carbon composite material. The first outer coating layer 5121 is made of silicon carbide and silicon, with silicon carbide accounting for 50%-99% of the mass and silicon accounting for 0%-15%. The first modified layer 5122 is made of silicon carbide, carbon-carbon composite material, and silicon, with silicon carbide accounting for 10%-50% of the mass, carbon-carbon composite material accounting for 20%-95% of the mass, and silicon accounting for 0%-15%.

[0104] In this embodiment of the invention, addressing the issue that the top section of the crucible side is susceptible to corrosion by silicon vapor in the prior art, a corrosion-resistant layer is formed on the top section of the carbon-carbon matrix of the crucible side during the fabrication of the crucible side 50 in the hot zone product. This results in the top section of the prepared crucible side 50 possessing corrosion-resistant properties, eliminating the need to focus on other parts less susceptible to silicon vapor corrosion, thereby reducing the fabrication cost of the crucible side 50. In this embodiment of the invention, the service life of the crucible side 50 prepared by the above method is extended by approximately two months compared to the service life of a crucible side using only carbon-carbon composite materials. Furthermore, for the crucible side, the method of locally fabricating a corrosion-resistant layer does not affect the heat transfer of the single crystal furnace compared to a full coating; and the method of locally fabricating a corrosion-resistant layer, compared to a full coating, does not cause excessive weight increase in the crucible side, thus avoiding imbalance of the supporting rods and the risk of silicon leakage.

[0105] The method of using a crucible side receiving fixture to coat the top section of the crucible side carbon-carbon matrix with melt-infiltrating powder includes: preparing a crucible side receiving fixture corresponding to the crucible side carbon-carbon matrix; placing the top section of the crucible side carbon-carbon matrix inside the crucible side receiving fixture; and filling the crucible side receiving fixture and the crucible side carbon-carbon matrix with melt-infiltrating powder so that the melt-infiltrating powder coats the top section of the crucible side carbon-carbon matrix.

[0106] Specifically, the 30-piece crucible side container fixture... Figure 3As shown. The height of the crucible side receiving fixture 30 is less than or equal to the height of the crucible side carbon-carbon matrix 40, and greater than or equal to the height of the top section of the crucible side carbon-carbon matrix 40. The filling thickness of the melt-infiltrating powder is 1mm-30mm. Preferably, the filling thickness of the melt-infiltrating powder is 2mm-20mm. When the top section of the crucible side carbon-carbon matrix 40 is placed inside the crucible side receiving fixture 30, a gap of 1mm-30mm should be maintained between the top section of the crucible side carbon-carbon matrix 40 and the crucible side receiving fixture 30 to facilitate the filling of the melt-infiltrating powder. During filling, the melt-infiltrating powder is specifically filled between the outer surface of the top section of the crucible side carbon-carbon matrix 40 and the crucible side receiving fixture 30, so that the melt-infiltrating powder covers the outer surface of the top section of the crucible side carbon-carbon matrix 40. It should be noted that when the top section of the crucible side carbon-carbon matrix 40 is placed inside the crucible side receiving fixture 30, the top surface of the crucible side carbon-carbon matrix 40 is in contact with the crucible side receiving fixture 30. Both the heat shield container 10 and the crucible side container 30 can be made of high-temperature resistant materials, such as graphite.

[0107] In this embodiment of the invention, the crucible side receiving fixture 30 facilitates the coating of the melt-infiltrating powder onto the top section of the crucible side carbon matrix 40 according to the required thickness, thereby ensuring the uniformity of the thickness of the melt-infiltrating powder.

[0108] The infiltrated powder also includes carbon powder and / or silicon carbide powder, with silicon powder accounting for 50%-100% by mass, carbon powder accounting for 0%-50% by mass, and silicon carbide powder accounting for 0%-10% by mass.

[0109] Specifically, the toner can be of a particle size of 10um-100um, and the silicon carbide powder can be of a particle size of less than 230um. During the reaction melting process, silicon reacts with pyrolytic carbon and graphite powder in the carbon matrix to form silicon carbide.

[0110] The preferred mass percentage of silicon powder is 50%-85%, with specific values ​​including 50%, 60%, 70%, 75%, 82%, and 85%. The preferred mass percentage of carbon powder is 0%-15%, with specific values ​​including 0%, 5%, 8%, 10%, 12%, and 15%. The specific mass percentage of silicon carbide powder can be 0%, 4%, 5%, 6%, 7%, and 10%.

[0111] As shown in Table 1, when the infiltrated powder includes silicon powder, carbon powder, and / or silicon carbide powder, the specific mass percentages of each powder are as follows: In Examples 2, 5, and 8, the mass percentage of silicon powder is 85%, and the mass percentage of carbon powder is 15%; in Examples 3, 6, and 9, the mass percentage of silicon powder is 82%, the mass percentage of carbon powder is 12%, and the mass percentage of silicon carbide powder is 6%. The difference between Examples 5 and 8 and Example 2 lies in the different filling thicknesses of the infiltrated powder, and the difference between Examples 6 and 9 and Example 3 lies in the different filling thicknesses of the infiltrated powder.

[0112] When the mass ratio of silicon powder is too high, the molten silicon solution will not only react with the pyrolytic carbon in the carbon-carbon matrix, but will also further react with the carbon fibers in the carbon-carbon matrix, causing damage to the carbon fibers and leading to a decrease in the mechanical properties of the thermal field product. Therefore, carbon powder is added to the melt-infiltrating powder so that the excess silicon powder can react directly with the carbon powder, thereby avoiding the damage to the carbon fibers caused by the excess silicon powder.

[0113] Furthermore, if the mass ratio of silicon powder is too high, a large amount of elemental silicon will remain after the reaction with carbon powder. During the use of the heat shield product, the residual elemental silicon melts and flows out of the heat shield product, affecting its use. Therefore, in this embodiment of the invention, the mass ratio of silicon powder is preferably controlled at 50%-85% to avoid the silicon powder mass ratio being too high.

[0114] Silicon carbide powder has a very high melting point and exists as powder particles throughout the heat treatment process. Therefore, the content of silicon carbide powder should not be too high and should be controlled between 0% and 10% to avoid the reduction in the bonding strength between the carbon matrix and the corrosion-resistant layer caused by residual silicon carbide particles.

[0115] In Examples 1, 4, and 7 in Table 1, the mass percentage of silicon powder is 100%, meaning the melt-infiltrated powder consists only of silicon powder. The difference between Examples 4 and 7 and Example 1 is the different filling thickness of the melt-infiltrated powder.

[0116] The infiltrated powder also includes alumina powder, which accounts for 0%-6% of the total mass.

[0117] Specifically, the alumina powder can be alumina powder with a particle size of less than 100 μm. In this embodiment of the invention, the addition of alumina powder can reduce the activation energy of the molten liquid silicon, thereby improving the diffusion ability of the liquid silicon and ensuring that the molten liquid silicon penetrates into the carbon-carbon matrix from the outside to the inside.

[0118] Since oxygen and aluminum are considered impurity elements for thermal products, the mass percentage of alumina powder must be controlled within a low range. The purity requirements for the melt-infiltrating powder are extremely high; the impurity content must be controlled to <200 ppm.

[0119] Step 103, the reactive melting process, includes:

[0120] A heat shield container with a carbon-carbon substrate and filled with melt-infiltrating powder is placed in a reaction melt-infiltrating furnace, and reaction melt-infiltrating is carried out under inert gas protection and at a temperature of 1500℃-2200℃; and / or, a crucible side container with a carbon-carbon substrate and filled with melt-infiltrating powder is placed in a reaction melt-infiltrating furnace, and reaction melt-infiltrating is carried out under inert gas protection and at a temperature of 1500℃-2200℃.

[0121] Specifically, nitrogen or argon can be used as the inert gas. The reaction time for reactive melting can be 1-1.5 hours. The reactive melting process can be performed once or twice using the same technique. After the reactive melting is completed, the product can be surface polished and ground to obtain a thermally deposited product. In this embodiment of the invention, by conducting the reactive melting under inert gas protection, oxidation of the melted powder after heating is avoided.

[0122] Reference Figure 5 and Figure 6 The heat shield receiving fixture 10 includes a first receiving cavity 11 with a depth H1 of 120mm-130mm. The crucible side receiving fixture 30 includes a fixture body 33, a second receiving cavity 31, and a second protrusion 32. The maximum depth formed by the second receiving cavity 31 and the fixture body 33 or the second protrusion 32 is H2. The height of H2 is determined by the height of the subsequently prepared crucible side modified section 51; for example, the maximum depth H2 can be 110mm-300mm. Placing the bottom section of the heat shield carbon-carbon substrate in the heat shield receiving fixture includes placing the bottom section of the heat shield carbon-carbon substrate in the first receiving cavity of the heat shield receiving fixture. Placing the top section of the crucible side carbon-carbon substrate in the crucible side receiving fixture includes placing the top section of the crucible side carbon-carbon substrate in the second receiving cavity of the crucible side receiving fixture.

[0123] Specifically, refer to Figure 5 The first accommodating cavity 11 has a first sidewall 111 and a first bottom wall 112 connected to the first sidewall 111. The first sidewall 111 and the first bottom wall 112 are connected by a rounded chamfer, the radius of which is the same as the radius of the rounded segment of the heatsink carbon-carbon substrate 20. A first protrusion 12 is provided on the first bottom wall 112. The cross-section of the first protrusion 12 is circular, and the diameter of the first protrusion 12 is less than or equal to the diameter of the bottom opening of the heatsink carbon-carbon substrate 20. The difference between the diameter of the bottom opening of the heatsink carbon-carbon substrate 20 and the diameter of the first protrusion 12 is within 10 mm. The height of the first protrusion 12 can be 10 mm to 100 mm. When the bottom segment of the heatsink carbon-carbon substrate 20 is placed in the first accommodating cavity 11, the bottom segment of the heatsink carbon-carbon substrate 20 is located between the first protrusion 12 and the first sidewall 111.

[0124] Reference Figure 6 The second accommodating cavity 31 has a second sidewall 311 and a second bottom wall 312 connected to the second sidewall 311. A second boss 32 is provided on the second bottom wall 312. The second boss 32 has a circular cross-section, and its diameter is less than or equal to the diameter of the opening of the top section of the crucible carbon-carbon matrix 40, with the difference between the diameter of the opening of the top section of the crucible carbon-carbon matrix 40 and the diameter of the second boss 32 being within 10 mm. The height of the tooling body 33 and the second boss 32 are set according to the position and height of the corrosion-resistant layer to be prepared.

[0125] For example, to prepare a corrosion-resistant layer 512 on the crucible side away from the crucible mounting cavity, refer to... Figure 6 The second protrusion 32 needs to be lower than the tooling body 33, and the tooling body 33 and the second receiving cavity 31 form a maximum depth H2. For example, the height of the tooling body 33 can be 110mm-300mm, and the height of the second protrusion 32 can be 10mm-100mm. When the top section of the crucible side carbon-carbon matrix 40 is placed in the second receiving cavity 31, the top surface of the crucible side carbon-carbon matrix 40 is in contact with the second bottom wall 312, and the gap between the outer surface of the top section of the crucible side carbon-carbon matrix 40 and the second side wall 311 is 1mm-30mm. The filling thickness of the melt-infiltrating powder is 1mm-30mm. When the top section of the crucible side carbon-carbon matrix 40 is placed in the crucible side receiving tooling 30, a gap of 1mm-30mm must be maintained between the outer surface of the top section of the crucible side carbon-carbon matrix 40 and the second side wall 311 to facilitate the filling of the melt-infiltrating powder. When the melt-infiltrating powder is filled, it is specifically filled between the outer surface of the top section of the crucible side carbon-carbon matrix 40 and the second sidewall 311, so that the melt-infiltrating powder covers the outer surface of the top section of the crucible side carbon-carbon matrix 40.

[0126] For example, to prepare a crucible side corrosion-resistant layer 512 near the crucible mounting cavity, the height of the tooling body 33 needs to be lower than the height of the second protrusion 32. The second protrusion 32 and the second receiving cavity 31 form a maximum depth H2. For example, the height of the second protrusion 32 can be 110mm-300mm, and the height of the tooling body 33 can be 10mm-100mm. When the top section of the crucible side carbon-carbon matrix 40 is placed in the second receiving cavity 31, the top surface of the crucible side carbon-carbon matrix 40 is in contact with the second bottom wall 312, and the gap between the inner surface of the top section of the crucible side carbon-carbon matrix 40 and the second protrusion 32 is 1mm-30mm. The filling thickness of the melt-infiltrated powder is 1mm-30mm. When the top section of the crucible side carbon-carbon matrix 40 is placed in the crucible side receiving tooling 30, a gap of 1mm-30mm needs to be maintained between the inner surface of the top section of the crucible side carbon-carbon matrix 40 and the second protrusion 32 to facilitate the filling of the melt-infiltrated powder. When the melt-infiltrating powder is filled, it is specifically filled between the inner surface of the top section of the crucible side carbon-carbon matrix 40 and the second protrusion 32, so that the melt-infiltrating powder covers the inner surface of the top section of the crucible side carbon-carbon matrix 40.

[0127] Furthermore, if it is necessary to prepare a crucible side corrosion-resistant layer 512 close to and within the crucible mounting cavity, the tooling body 33 and the second protrusion 32 are flush, forming a maximum depth H2. For example, the height of the tooling body 33 and the second protrusion 32 can be 110mm-300mm. When the top section of the crucible side carbon-carbon matrix 40 is placed in the second accommodating cavity 31, the top surface of the crucible side carbon-carbon matrix 40 is in contact with the second bottom wall 312. The gap between the outer surface of the top section of the crucible side carbon-carbon matrix 40 and the second side wall 311 is 1mm-30mm, and the gap between the inner surface of the top section of the crucible side carbon-carbon matrix 40 and the second protrusion 32 is 1mm-30mm. The filling thickness of the melt-infiltrated powder is 1mm-30mm. When the melt-infiltrating powder is filled, it is specifically filled between the outer surface of the top section of the crucible side carbon-carbon matrix 40 and the second sidewall 311, and between the inner surface of the top section of the crucible side carbon-carbon matrix 40 and the second protrusion 32, so that the melt-infiltrating powder covers the outer and inner surfaces of the top section of the crucible side carbon-carbon matrix 40.

[0128] It should be noted that when the top section of the crucible side carbon-carbon substrate 40 is placed inside the crucible side receiving fixture 30, the top surface of the crucible side carbon-carbon substrate 40 is in contact with the crucible side receiving fixture 30. The crucible side receiving fixture 30 can be made of a high-temperature resistant material, such as graphite.

[0129] In this embodiment of the invention, the placement of the heat shield carbon-carbon substrate 20 and the crucible side carbon-carbon substrate 40 is facilitated by the setting of the first accommodating cavity 11 and the second accommodating cavity 31. Furthermore, the height of the filled melt-infiltrated powder is within a suitable range by setting the depth of the first accommodating cavity 11 and the maximum depth of the second accommodating cavity 31 within the aforementioned range.

[0130] Step 102, preparing the melt-infiltrated powder, further includes:

[0131] Prepare silicon powder, carbon powder, silicon carbide powder and alumina powder, and mix them evenly to obtain melt-infiltrated powder.

[0132] Specifically, silicon powder, carbon powder, silicon carbide powder, and alumina powder are prepared according to the following proportions: silicon powder 50%-100% by mass, carbon powder 0%-50% by mass, silicon carbide powder 0%-10% by mass, and alumina powder 0%-6% by mass. Then, the prepared silicon powder, carbon powder, silicon carbide powder, and alumina powder are stirred and mixed using a mixer for 0.2h-2h to ensure uniform mixing. In this embodiment of the invention, by ensuring uniform mixing of the prepared silicon powder, carbon powder, silicon carbide powder, and alumina powder, the uniform distribution of silicon carbide generated during the reaction and infiltration process is guaranteed.

[0133] Step 101 involves preparing a carbon-carbon matrix using carbon-carbon composite materials, including:

[0134] Carbon fiber preforms are prepared using carbon fiber.

[0135] Specifically, carbon fiber can be used as the raw material, and a 2.5D preform needle punching process can be employed to prepare a material with a density of 0.35 g / cm³. 3 -0.6g / cm 3 The prefabricated structure.

[0136] Carbon fiber preforms were densified using chemical vapor deposition to obtain carbon-carbon composite materials.

[0137] Specifically, the density of the carbon-carbon composite material obtained after densification is 0.8 g / cm³. 3 -1.45g / cm 3 The feed gas used in chemical vapor deposition (CVD) is one or more of natural gas, propane, ethylene, and acetylene. The feed gas inlet rate can be determined according to the dimensions of different furnace types. The ratio of the working space volume of the furnace cavity to the feed gas inlet velocity is 1:4 to 1:0.5. The unit of the working space volume of the furnace cavity is cubic meters, and the unit of the inlet velocity is cubic meters per hour under standard conditions. The carrier gas used in CVD is one or more of argon, nitrogen, and hydrogen. The ratio of the feed gas volume to the carrier gas volume is 2:4 to 2:0. The pyrolysis temperature in the furnace during CVD can be 900℃-1200℃, and the working zone pressure can be 1kPa-10kPa.

[0138] Graphitization treatment is applied to carbon-carbon composite materials.

[0139] Specifically, the graphitization treatment temperature is 1500℃-2500℃, the treatment time is 1h-10h, and the degree of graphitization is 5%-45%. The specific treatment time can be 1h, 2h, 3h, 5h, 7h, 10h, etc.

[0140] The graphitized carbon-carbon composite material is processed according to the processing dimensions of the hot zone product to obtain the intermediate matrix.

[0141] Specifically, when preparing the heat shield 60, the graphitized carbon-carbon composite material is processed according to the processing dimensions of the heat shield 60. When preparing the crucible side 50, the graphitized carbon-carbon composite material is processed according to the processing dimensions of the crucible side 50.

[0142] A carbon-carbon matrix is ​​obtained by depositing pyrolytic carbon on the surface of an intermediate matrix using chemical vapor deposition.

[0143] Specifically, the chemical vapor deposition (CVD) process used in this step is the same as that used in the densification step. The processing time of this step is approximately 0.1-0.2 times that of the densification step.

[0144] In this embodiment of the invention, the densification process in the preparation of carbon-carbon composite materials is carried out by chemical vapor deposition, which results in high strength and less fiber damage in the prepared carbon-carbon composite materials.

[0145] Secondly, embodiments of the present invention also disclose a single-crystal furnace hot zone, comprising a hot zone product prepared by any of the above-described hot zone product preparation methods. The hot zone product includes a heat shield 60 and / or a crucible side 50. Since the hot zone product in the single-crystal furnace hot zone is prepared by the above-described hot zone product preparation methods, it also possesses the beneficial effects of the above-described hot zone product preparation methods, which will not be elaborated further here.

[0146] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0147] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for preparing a thermal field product, characterized in that, The heat field product includes a heat shield and a crucible side, and the method for preparing the heat field product includes: The preparation of carbon-carbon matrix using carbon-carbon composite materials includes: preparing a heat shield carbon-carbon matrix using carbon-carbon composite materials, and preparing a crucible side carbon-carbon matrix using carbon-carbon composite materials; Prepare melt-infiltrating powder, wherein the melt-infiltrating powder includes silicon powder; The hot zone product is obtained by partially coating the carbon-carbon matrix with the melt-infiltrating powder and performing reactive melt-infiltrating to locally form a corrosion-resistant layer on the carbon-carbon matrix. This includes: coating the bottom section of the heat shield carbon-carbon matrix with the melt-infiltrating powder and performing reactive melt-infiltrating to form a corrosion-resistant layer on the bottom section of the heat shield carbon-carbon matrix, thereby obtaining the heat shield; and coating the top section of the crucible side carbon-carbon matrix with the melt-infiltrating powder and performing reactive melt-infiltrating to form a corrosion-resistant layer on the top section of the crucible side carbon-carbon matrix, thereby obtaining the crucible side. The materials of the heat shield corrosion-resistant layer and the crucible side corrosion-resistant layer include silicon carbide.

2. The method for preparing a thermal field product according to claim 1, characterized in that, The process of coating the bottom section of the heat shield carbon matrix with the melt-infiltrating powder includes: Prepare a heat shield receiving fixture corresponding to the heat shield carbon-carbon substrate, wherein the height of the heat shield receiving fixture is lower than the height of the heat shield carbon-carbon substrate; The bottom section of the carbon-carbon substrate of the heat shield is placed inside the heat shield housing fixture; The melt-infiltrating powder is filled between the heat shield receiving fixture and the heat shield carbon-carbon matrix, so that the melt-infiltrating powder covers the bottom section of the heat shield carbon-carbon matrix, wherein the filling thickness of the melt-infiltrating powder is 2mm-20mm.

3. The method for preparing a thermal field product according to claim 2, characterized in that, The top section that coats the crucible side carbon-carbon matrix with the melt-infiltrating powder includes: Prepare a crucible side receiving fixture corresponding to the crucible side carbon-carbon matrix, wherein the height of the crucible side receiving fixture is lower than the height of the crucible side carbon-carbon matrix; The top section of the crucible side carbon-carbon matrix is ​​placed inside the crucible side receiving fixture; The melt-infiltrating powder is filled between the crucible side receiving fixture and the crucible side carbon-carbon matrix, so that the melt-infiltrating powder covers the top section of the crucible side carbon-carbon matrix, wherein the filling thickness of the melt-infiltrating powder is 2mm-20mm.

4. The method for preparing a thermal field product according to claim 1, characterized in that, The infiltrated powder further includes carbon powder and / or silicon carbide powder, wherein the silicon powder accounts for 50%-100% by mass, the carbon powder accounts for 0%-50% by mass, and the silicon carbide powder accounts for 0%-10% by mass.

5. The method for preparing a thermal field product according to claim 4, characterized in that, The silicon powder accounts for 50%-85% of the total mass, and the carbon powder accounts for 0%-15% of the total mass.

6. The method for preparing a thermal field product according to claim 4, characterized in that, The infiltrated powder also includes alumina powder, which accounts for 0%-6% of the total mass.

7. The method for preparing a thermal field product according to claim 3, characterized in that, The reaction melting and infiltration process includes: The heat shield container, which contains the carbon-carbon substrate and is filled with the melt-infiltrating powder, is placed in a reaction melt-infiltrating furnace and reacted and melt-infiltrated under inert gas protection at a temperature of 1500℃-2200℃. And / or, the crucible side container, which has the crucible side carbon-carbon matrix and is filled with the melting powder, is placed in a reaction melting furnace and the reaction melting is carried out under inert gas protection and at a temperature of 1500℃-2200℃.

8. The method for preparing a thermal field product according to claim 3, characterized in that, The hot screen receiving fixture includes a first receiving cavity with a depth of 120mm-130mm. The crucible side receiving fixture includes a fixture body, a second receiving cavity, and a second boss. The maximum depth formed by the second receiving cavity and the fixture body or the second boss is 110mm-300mm. Placing the bottom section of the carbon-carbon substrate of the heat shield within the heat shield housing fixture includes: The bottom section of the heat shield carbon-carbon substrate is placed in the first receiving cavity of the heat shield receiving fixture; Placing the top section of the crucible side carbon-carbon matrix within the crucible side receiving fixture includes: The top section of the crucible side carbon matrix is ​​placed in the second receiving cavity of the crucible side receiving fixture.

9. The method for preparing a thermal field product according to claim 6, characterized in that, The preparation of the melt-infiltrated powder includes: Silicon powder, carbon powder, silicon carbide powder and alumina powder are prepared, and the silicon powder, carbon powder, silicon carbide powder and alumina powder are mixed evenly to obtain melt-infiltrated powder.

10. The method for preparing a thermal field product according to claim 1, characterized in that, The preparation of a carbon-carbon matrix using carbon-carbon composite materials includes: Carbon fiber preforms are prepared using carbon fiber. The carbon fiber preform was densified using chemical vapor deposition to obtain a carbon-carbon composite material. The carbon-carbon composite material is subjected to graphitization treatment; The graphitized carbon-carbon composite material is processed according to the processing dimensions of the aforementioned thermal field product to obtain an intermediate matrix; Pyrolytic carbon is deposited on the surface of the intermediate matrix using chemical vapor deposition to obtain a carbon-carbon matrix.

11. A hot zone for a single crystal furnace, characterized in that, This includes thermal field products prepared using the thermal field product preparation method according to any one of claims 1 to 10.

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