Composite coating, method for preparing the same, carbon / carbon crucible and application thereof

Abstract

The present application relates to a kind of composite coating and its preparation method, carbon / carbon crucible and application.The composite coating is combined on the surface of carbon / carbon substrate;The composite coating includes resin baked product and graphite carbon substance, first carbon substance and second carbon substance, wherein, at least a part of resin baked product first carbon substance forms the skeleton with connected channel, and at least a part of graphite carbon substance second carbon substance is filled in connected channel.The composite coating is combined closely with carbon / carbon substrate, can be better resistant to corrosion, and service life is longer.The preparation method provided is first formed on the skeleton coating of carbon / carbon substrate, then carbon particles are filled in the channel of skeleton coating using vapor deposition method, process is simple, easy to process, production efficiency is high and the yield is high, and the composite coating prepared is combined closely with carbon / carbon substrate, the chemical stability of coating is high, can effectively prolong the service life of hot field structure.

Description

Technical Field

[0001] This invention relates to the field of composite coating technology, and in particular to a composite coating and its preparation method, a carbon / carbon crucible and its application. Background Technology

[0002] Carbon / carbon crucibles, due to their high strength, high thermal stability, and wear resistance, have become an important component in the energy, automotive, aerospace, and machinery industries. Some applications, such as energy manufacturing, have stringent requirements for the precision and reliability of carbon / carbon crucibles, often relying on frequent crucible replacements to meet process requirements, leading to high application costs. Therefore, there is a need to optimize the performance of carbon / carbon crucibles and provide products with high stability and long service life that meet application needs. Summary of the Invention

[0003] Based on this, the purpose of this application includes providing a composite coating and its preparation method, a carbon / carbon crucible and its application.

[0004] The composite coating of this application comprises a coating of resin calcined material and graphite-based carbon material. The composite coating is tightly bonded to the carbon / carbon substrate and is corrosion resistant. Carbon / carbon crucibles with this composite coating have a long service life.

[0005] A first aspect of this application provides a composite coating bonded to the surface of a carbon / carbon substrate;

[0006] The composite coating comprises a calcined resin and a graphite-based carbon material, wherein at least a portion of the calcined resin forms a framework with interconnected channels, and at least a portion of the graphite-based carbon material fills the interconnected channels.

[0007] The graphite-based carbonaceous material includes a first carbonaceous material and a second carbonaceous material; the first carbonaceous material includes flake graphite powder and pyrolytic graphite; the second carbonaceous material includes carbonaceous particles.

[0008] In some embodiments, the composite coating satisfies one or more of the following characteristics:

[0009] The mass ratio of the flake graphite powder to the pyrolytic graphite is 8:2 to 9.9:0.1;

[0010] The thickness of the composite coating is 0.3 mm to 3 mm;

[0011] The density of the composite coating is 1.0 g / cm³. 3 ~1.8g / cm 3 ;

[0012] The main material of the surface layer in contact with the composite coating in the carbon / carbon substrate is a carbon / carbon composite material;

[0013] The main material of the carbon / carbon substrate is a carbon / carbon composite material;

[0014] The matrix material of the carbon / carbon substrate includes graphite.

[0015] A second aspect of this application provides a method for preparing the composite coating described in the first aspect, comprising the following steps:

[0016] The first carbon material, polymer resin, and alcohol solvent are mixed to obtain the first slurry;

[0017] The first slurry is applied to the surface of a carbon / carbon substrate and dried to form a pre-coating layer bonded to the surface of the carbon / carbon substrate.

[0018] Under an inert atmosphere, the pre-coating is heat-treated to form a skeleton coating with interconnected channels in the polymer resin, and the first carbon material is attached to at least a portion of the skeleton to obtain a skeleton coating including graphitic carbon material.

[0019] In the presence of a precursor material of the second carbon material, the framework coating comprising graphite-based carbon material is subjected to vapor deposition to form a composite coating containing the second carbon material; wherein at least a portion of the second carbon material fills the communicating channels.

[0020] In some embodiments, the preparation method satisfies one or more of the following characteristics:

[0021] The first carbon material includes flake graphite powder and pyrolytic graphite, wherein the particle size of the flake graphite powder is 100 mesh to 10,000 mesh; and the particle size of the pyrolytic graphite is 100 mesh to 500 mesh.

[0022] The mass ratio of 500-mesh pyrolytic graphite, 100-mesh flake graphite powder, 500-mesh flake graphite powder and 10000-mesh flake graphite powder in the first carbon material is (0.1~2):(0.1~1):(5~10):(0.1~2).

[0023] In some embodiments, the preparation method satisfies one or more of the following characteristics:

[0024] The mass ratio of the polymer to the solvent in the first slurry is (85-99):(1-15);

[0025] The ratio of the mass of the first carbon substance in the first slurry to the sum of the masses of the polymer resin and the alcohol solvent is 1:(0.75~4).

[0026] In some embodiments, in the preparation method, the pre-coating is heat-treated under an inert atmosphere to form a skeleton with interconnected channels, and the first carbon material is attached to at least a portion of the skeleton to obtain a skeleton coating comprising graphitic carbon material. In this step, the heat treatment temperature is 900°C to 1200°C and the heat treatment time is 2h to 20h.

[0027] In some embodiments, in the preparation method, in the step of performing vapor deposition on the framework coating comprising graphitic carbon material to form a composite coating containing the second carbon material in the presence of the precursor material of the second carbon material, the vapor deposition temperature is 900℃~1400℃ and the time is 5h~50h.

[0028] A third aspect of this application provides a carbon / carbon crucible comprising a carbon / carbon substrate and a composite coating bonded to the surface of the carbon / carbon substrate, the composite coating comprising at least one of the composite coating described in the first aspect and the composite coating prepared by the preparation method described in the second aspect.

[0029] A fourth aspect of this application provides an application of the carbon / carbon crucible described in the third aspect in a high-temperature process, wherein the high-temperature process includes a high-temperature treatment step of at least 1400°C to 1800°C.

[0030] A fifth aspect of this application provides an application of the carbon / carbon crucible described in the third aspect in the preparation of single-crystal silicon, comprising the following steps: placing the carbon / carbon crucible in a thermal field of at least 1400°C to 1600°C.

[0031] The composite coating provided in this application includes resin calcined material and graphite-based carbon material. The skeleton has internally interconnected channels for accommodating carbon particles. The composite coating is tightly bonded to the carbon / carbon substrate, has good corrosion resistance, and a long service life.

[0032] The preparation method provided in this application first forms a skeleton coating on a carbon / carbon substrate, and then fills the pores of the skeleton coating with carbon particles by vapor deposition. The process is simple, easy to process, has high production efficiency and high yield. Moreover, the prepared composite coating is tightly bonded to the carbon / carbon substrate and has high chemical stability, which can effectively extend the service life of thermal field structural components.

[0033] The carbon / carbon substrate in the carbon / carbon crucible provided in this application is tightly bonded to the composite coating, exhibiting good corrosion resistance and a long service life.

[0034] The carbon / carbon crucible used in this application has high chemical stability, can meet the stringent requirements of high-temperature processes, and has low cost and long service life.

[0035] The carbon / carbon crucible provided in this application has high reliability in the preparation of single-crystal silicon and can also reduce the overall process cost. Detailed Implementation

[0036] To facilitate understanding of the present invention, a more comprehensive description is provided below, along with preferred embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0037] The implementation of the present invention will be described in detail below with reference to some embodiments and examples. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0039] the term

[0040] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings:

[0041] In this invention, the terms "multiple" or "various" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0042] In this invention, terms such as "further" and "particularly" are used for descriptive purposes and to indicate differences in content, but should not be construed as limiting the scope of protection of this invention.

[0043] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0044] In this invention, numerical intervals (i.e., numerical ranges) are involved. Unless otherwise specified, the distribution of selectable values ​​within a numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include numerical interval types such as percentage intervals, ratio intervals, and proportion intervals.

[0045] In this invention, the term "room temperature" generally refers to 4℃ to 35℃, and preferably 20℃ ± 5℃. In some embodiments of this invention, room temperature refers to 20℃ to 30℃.

[0046] In this invention, unless otherwise specified, the temperature parameters are allowed to be either constant temperature or vary within a certain temperature range. It should be understood that the constant temperature treatment allows temperature fluctuations within the precision range controlled by the instrument. Fluctuations are permitted within ranges such as ±5℃, ±4℃, ±3℃, ±2℃, and ±1℃.

[0047] In this invention, if the unit of a data range is only followed by the right endpoint, it indicates that the units of the left and right endpoints are the same. For example, 2-5h means that the units of the left endpoint "2" and the right endpoint "5" are both h (hours).

[0048] Carbon / carbon crucibles (a type of thermal field structural component) have become an important part of the energy, automotive, aerospace, and machinery industries due to their advantages such as high strength, high thermal stability, and wear resistance. Some applications, such as energy manufacturing, have stringent requirements for the precision and reliability of carbon / carbon crucibles, often relying on frequent crucible replacements to meet process requirements, leading to high application costs. Therefore, there is a need to optimize the performance of carbon / carbon crucibles and provide products with high stability and long service life that meet application needs.

[0049] Monocrystalline silicon is a crucial raw material in manufacturing, primarily produced industrially using the Czochralski (CZ) method. This method requires loading high-purity silicon into a quartz crucible and heating it to 1600°C to melt the silicon. At this high temperature, ordinary structural components, such as the quartz crucible itself, soften. A typical approach is to place the quartz crucible within a carbon-carbon composite crucible, with the carbon / carbon crucible supporting the softened quartz. Currently, the lifespan of carbon / carbon crucibles used in monocrystalline silicon thermal environments is approximately six months, resulting in short service life and high cost. Furthermore, in terms of manufacturing processes, traditional coating methods typically involve direct vapor deposition. However, direct vapor deposition produces coatings with poor thickness and uniformity, and the deposition time is lengthy, exceeding 100 hours, leading to low production efficiency and yield.

[0050] Based on this, the purpose of this application includes providing a composite coating and its preparation method, a carbon / carbon crucible and its application.

[0051] The composite coating of this application comprises a coating of resin calcined material and graphite-based carbon material. The composite coating is tightly bonded to the carbon / carbon substrate and is corrosion resistant. Carbon / carbon crucibles with this composite coating have a long service life.

[0052] A first aspect of this application provides a composite coating bonded to the surface of a carbon / carbon substrate;

[0053] The composite coating comprises a calcined resin and a graphite-based carbon material, wherein at least a portion of the calcined resin forms a framework with interconnected channels, and at least a portion of the graphite-based carbon material fills the interconnected channels.

[0054] The graphite-based carbonaceous material includes a first carbonaceous material and a second carbonaceous material; the first carbonaceous material includes flake graphite powder and pyrolytic graphite; the second carbonaceous material includes carbonaceous particles.

[0055] The composite coating provided in this application includes resin calcined material and graphite-based carbon material. The skeleton has internally interconnected channels for accommodating carbon particles. The composite coating is tightly bonded to the carbon / carbon substrate, has good corrosion resistance, and a long service life.

[0056] In some embodiments, the mass ratio of the flake graphite powder to the pyrolytic graphite in the composite coating is 8:2 to 9.9:0.1.

[0057] In some embodiments, the composite coating comprises, by weight, 8 to 9.9 parts of flake graphite powder, or any one or any two of the following weight percentages: 8 parts, 8.1 parts, 8.2 parts, 8.3 parts, 8.4 parts, 8.5 parts, 8.6 parts, 8.7 parts, 8.8 parts, 8.9 parts, 9 parts, 9.1 parts, 9.2 parts, 9.3 parts, 9.4 parts, 9.5 parts, 9.6 parts, 9.7 parts, 9.8 parts, and 9.9 parts.

[0058] In some embodiments, the composite coating comprises, by weight, 0.1 to 2 parts of flake graphite powder, or any one or any two of the following weight percentages: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, etc.

[0059] In some embodiments, the thickness of the composite coating is 0.3 mm to 3 mm, and may also be selected from any one or any two of the following thicknesses: 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3 mm, etc.

[0060] In some embodiments, the density of the composite coating is 1.0 g / cm³. 3 ~1.8g / cm 3 It can also be selected from any one of the following densities or a range consisting of any two densities: 1 g / cm³ 3 1.1g / cm 3 1.2g / cm 3 1.3g / cm 3 1.4g / cm 3 1.5g / cm 3 1.6g / cm 3 1.7g / cm 3 1.8 g / cm 3 wait.

[0061] In some embodiments, the main material of the surface layer in contact with the composite coating in the carbon / carbon substrate is a carbon / carbon composite material.

[0062] In some embodiments, the main material of the carbon / carbon substrate in the composite coating is a carbon / carbon composite material.

[0063] In some embodiments, the matrix material of the carbon / carbon substrate in the composite coating includes graphite.

[0064] In another aspect of this application, a coated article is provided, comprising a carbon / carbon substrate and a composite coating bonded to the surface of the carbon / carbon substrate.

[0065] For definitions of carbon / carbon substrates and composite coatings, please refer to the first aspect of this application.

[0066] A second aspect of this application provides a method for preparing the composite coating described in the first aspect, comprising the following steps:

[0067] The first carbon material, polymer resin, and alcohol solvent are mixed to obtain the first slurry;

[0068] The first slurry is applied to the surface of a carbon / carbon substrate and dried to form a pre-coating layer bonded to the surface of the carbon / carbon substrate.

[0069] Under an inert atmosphere, the pre-coating is heat-treated to remove volatilization, thereby forming a skeleton coating with interconnected channels on the polymer resin. The first carbon material is attached to at least a portion of the skeleton, resulting in a skeleton coating comprising graphitic carbon material.

[0070] In the presence of a precursor material of the second carbon material, the framework coating comprising graphite-based carbon material is subjected to vapor deposition to form a composite coating containing the second carbon material; wherein at least a portion of the second carbon material fills the communicating channels.

[0071] The preparation method provided in this application first forms a skeleton coating on a carbon / carbon substrate, and then fills the pores of the skeleton coating with carbon particles by vapor deposition. The process is simple, easy to process, has high production efficiency and high yield. Moreover, the prepared composite coating is tightly bonded to the carbon / carbon substrate and has high chemical stability, which can effectively extend the service life of thermal field structural components.

[0072] By first coating the crucible with a graphite powder solution and then performing a vapor deposition coating, the coating thickness can be effectively controlled, resulting in a more uniform, homogeneous, and dense coating. This significantly improves the appearance of the crucible and greatly enhances its resistance to silicon etching, thereby significantly extending the service life of the crucible (a typical example of a thermal field structure component) and drastically shortening the coating process time. Furthermore, the carbon component in the precursor solution used as raw material includes pyrolysis carbon byproducts from the carbon / carbon crucible production process, offering the following advantages: Firstly, the carbon / carbon crucible substrate material and the coated carbon powder are the same substance, improving the bonding strength between the substrate and the coating and avoiding problems such as low bonding strength and easy peeling caused by thermal expansion mismatch between different substances. Secondly, the reuse of pyrolysis carbon byproducts improves the utilization rate of raw materials for preparing carbon / carbon crucibles, eliminating the need for separate raw material procurement.

[0073] In some embodiments, the first carbon material in the preparation method includes flake graphite powder and pyrolytic graphite.

[0074] In some embodiments, the particle size of the flake graphite powder in the preparation method is 100 mesh to 10,000 mesh.

[0075] Understandably, the particle size of graphite-based carbonaceous raw materials in this application refers to the powdered graphite-based carbonaceous raw materials obtained by sieving through a sieve of a corresponding mesh size. For example, a particle size of 100 mesh for flake graphite powder means that the flake graphite powder raw material is obtained by sieving through a 100-mesh sieve.

[0076] In some embodiments, the pyrolytic graphite in the preparation method has a particle size of 100 mesh to 500 mesh, and may also be selected from any one of the following particle sizes or a range consisting of any two particle sizes: 100 mesh, 200 mesh, 300 mesh, 400 mesh, 500 mesh, etc.

[0077] In this application, the carbon / carbon composite material is a carbon fiber / carbon matrix composite material, specifically a composite material in which carbon fiber is used as a reinforcement to reinforce a carbon matrix, and the carbon matrix is ​​formed by chemical vapor deposition.

[0078] In some embodiments, in the preparation method, the mass ratio of 500-mesh pyrolytic graphite, 100-mesh flake graphite powder, 500-mesh flake graphite powder and 10000-mesh flake graphite powder in the first carbon material is (0.1-2):(0.1-1):(5-10):(0.1-2), further can be (0.5-2):(0.6-1):(6-9):(1-2), and even further can be 0.5:1:7.5:1.

[0079] In some embodiments, the preparation method comprises, by mass parts, 0.1 to 2 parts of 500-mesh pyrolytic graphite, 0.1 to 1 part of 100-mesh flake graphite powder, 5 to 10 parts of 500-mesh flake graphite powder, and 0.1 to 2 parts of 10,000-mesh flake graphite powder.

[0080] In some embodiments, in the preparation method, the 0.1 to 2 parts by mass of 500-mesh pyrolytic graphite included in the first carbon material may also be selected from any one or any two of the following mass parts: 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, 2 parts, etc.

[0081] In some embodiments, in the preparation method, the 0.1 to 1 part of 100-mesh flake graphite powder included in the first carbon material, calculated by mass parts, may also be selected from any one or any two mass parts ranges: 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, etc.

[0082] In some embodiments, in the preparation method, the 5 to 10 parts of 500-mesh flake graphite powder included in the first carbon material, calculated by mass parts, may also be selected from any one or any two mass parts ranges: 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.

[0083] In some embodiments, in the preparation method, the 0.1 to 2 parts by mass of 10,000-mesh flake graphite powder included in the first carbon material may also be selected from any one or any two of the following mass parts: 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, 2 parts, etc.

[0084] In some embodiments, in the preparation method, the mass ratio of the polymer to the solvent in the first slurry is (85-99):(1-15), further it can be (85-90):(10-15), and even further it can be 90:10.

[0085] In some embodiments, in the preparation method, the ratio of the mass of the first carbon substance in the first slurry to the sum of the masses of the polymer resin and the alcohol solvent is 1:(0.75-4), and may also be selected from any of the following mass ratios or a range consisting of any two mass ratios: 1:0.75, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1. 5. Possible ratios include 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, 1:3, 1:3.1, 1:3.2, 1:3.3, 1:3.4, 1:3.5, 1:3.6, 1:3.7, 1:3.8, 1:3.9, and 1:4. If this ratio is too high, it may result in a rough coating surface; if the ratio is too low, it may result in an uneven coating and poor performance.

[0086] In some embodiments, in the preparation method, the pre-coating is heat-treated under an inert atmosphere to form a framework with interconnected channels in the polymer resin, and the first carbon material is attached to at least a portion of the framework to obtain a framework coating comprising graphitic carbon material. In this step, the heat treatment temperature is 900°C to 1200°C, or more specifically, 1000°C to 1200°C, or selected from any one or any two of the following temperatures: 900°C, 910°C. Temperatures range from 920℃, 930℃, 940℃, 950℃, 960℃, 970℃, 980℃, 990℃, 1000℃, 1010℃, 1020℃, 1030℃, 1040℃, 1050℃, 1060℃, 1070℃, 1080℃, 1090℃, 1100℃, 1110℃, 1120℃, 1130℃, 1140℃, 1150℃, 1160℃, 1170℃, 1180℃, 1190℃, 1200℃, etc.

[0087] In some embodiments, in the preparation method, the pre-coating is heat-treated under an inert atmosphere to form a framework with interconnected channels in the polymer resin, and the first carbon material is attached to at least a portion of the framework to obtain a framework coating comprising graphitic carbon material. In this step, the heat treatment time is 2h to 20h, more specifically 5h to 6h, or can be selected from any one or any two of the following time intervals: 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.1h, 5.2h, 5.3h, 5.4h, 5.5h, 5.6h, 5.7h, 5.8h, 5.9h, 6h, 6.5h, 7h, 7.5h, 8h, 8.5h, 9h, 9.5h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, etc.

[0088] In some embodiments, in the preparation method, in the step of performing vapor deposition on the framework coating comprising graphitic carbon material to form a composite coating containing the second carbon material in the presence of a precursor material of the second carbon material, the vapor deposition temperature is between 900°C and 1400°C, further between 1200°C and 1300°C, or selected from any one or any two of the following temperatures: 900°C, 950°C, 1000°C, 1050°C, 1100°C, 1110°C. 1120℃, 1130℃, 1140℃, 1150℃, 1160℃, 1170℃, 1180℃, 1190℃, 1200℃, 1210℃, 1220℃, 1230℃, 1240℃, 1250℃, 1260℃, 1270℃, 1280℃, 1290℃, 1300℃, 1310℃, 1320℃, 1330℃, 1340℃, 1350℃, 1360℃, 1370℃, 1380℃, 1390℃, 1400℃, etc.

[0089] In some embodiments, in the preparation method, in the step of performing vapor deposition on the framework coating comprising graphitic carbon material to form a composite coating containing the second carbon material in the presence of the precursor material of the second carbon material, the vapor deposition time is 5h to 50h, further 5h to 20h, or selected from any one or any two of the following time intervals: 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 25h, 30h, 35h, 40h, 45h, 50h, etc.

[0090] A third aspect of this application provides a carbon / carbon crucible comprising a carbon / carbon substrate and a composite coating bonded to at least a portion of the surface of the carbon / carbon substrate, the composite coating comprising at least one of the composite coating described in the first aspect and a composite coating prepared by the preparation method described in the second aspect.

[0091] The carbon / carbon substrate in the carbon / carbon crucible provided in this application is tightly bonded to the composite coating, exhibiting good corrosion resistance and a long service life.

[0092] Unless otherwise specified, thermal field structural components refer to structural components used in thermal field environments, and carbon / carbon crucibles are a type of structural component. The shape of carbon / carbon crucibles is not limited in this application. Carbon / carbon crucibles can be flat plates, containers with edges, ring-shaped components, and other structural components with a certain shape and structure. Typical container-type structural components include holding boats, round crucibles, square crucibles, etc., and these containers may also include lids.

[0093] In another aspect of this application, a thermal field device is provided, comprising the carbon / carbon crucible described in the first aspect and the carbon / carbon crucible prepared by the preparation method described in the second aspect.

[0094] A fourth aspect of this application provides an application of the carbon / carbon crucible described in the third aspect in a high-temperature process, wherein the high-temperature process includes a high-temperature treatment step of at least 1400°C to 1800°C.

[0095] In some embodiments, the high-temperature process in the application includes at least a high-temperature treatment step of 1400℃ to 1800℃, and may further be 1400℃ to 1600℃, or may be selected from any one or any two of the following temperatures: 1400℃, 1450℃, 1500℃, 1550℃, 1600℃, 1650℃, 1700℃, 1750℃, 1800℃, etc.

[0096] The carbon / carbon crucible used in this application has high chemical stability, can meet the stringent requirements of high-temperature processes, and has low cost and long service life.

[0097] A fifth aspect of this application provides an application of the carbon / carbon crucible described in the third aspect in the preparation of single-crystal silicon, comprising the step of placing the carbon / carbon crucible in a thermal field of at least 1400°C to 1600°C. In some embodiments, the application includes at least a high-temperature treatment step of 1400°C to 1800°C, and may further be 1400°C to 1600°C, or may be selected from any one or any two of the following temperatures: 1400°C, 1450°C, 1500°C, 1550°C, 1600°C, etc.

[0098] The carbon / carbon crucible provided in this application has high reliability in the preparation of single-crystal silicon and can also reduce the overall process cost.

[0099] To facilitate understanding and implementation of the present invention, the following more specific and detailed embodiments and comparative examples that are easier to implement are provided for reference.

[0100] The following will further illustrate the concept, specific examples, and technical effects of the present invention with reference to embodiments, so as to provide a full understanding of the present invention. These descriptions are provided solely to help explain the present invention and should not be construed as limiting the scope of the claims.

[0101] Unless otherwise specified, the raw materials used in the following experiments can be purchased from the market.

[0102] Example 1

[0103] The preparation method of the coated carbon / carbon crucible is as follows:

[0104] (1) Pyrolytic graphite was sieved through a 500-mesh sieve, and different amounts of flake graphite powder were sieved through 100-mesh, 500-mesh and 10000-mesh sieves, respectively.

[0105] (2) Pyrolytic graphite and flake graphite powder are placed in a V-type mixer in a certain proportion and stirred to obtain mixed powder A; wherein, the mass ratio of 500 mesh pyrolytic graphite, 100 mesh flake graphite powder, 500 mesh flake graphite powder and 10000 mesh flake graphite powder in powder A (equivalent to graphite carbon raw material) is 0.5:1:7.5:1;

[0106] (3) Weigh anhydrous ethanol and phenolic resin and mix them in a liquid mixer in a certain proportion to obtain solution A; wherein, the mass ratio of anhydrous ethanol (solvent) and phenolic resin (polymer) in solution A is 90:10;

[0107] (4) Powder A and solution A are placed in a mixer to form slurry A; wherein the mass ratio of powder A and solution A is 1:2;

[0108] (5) Clean the surface of the crucible base with an air gun;

[0109] (6) Coat the surface of the crucible substrate with slurry A and immerse and dry it at room temperature (20-30℃) for 5 hours;

[0110] (7) Nitrogen gas is introduced into the dried crucible environment and kept at 1000℃ for 5 hours. The temperature is then raised to 1200℃. Nitrogen gas is stopped, and natural gas is introduced and kept at 1200℃ for 5 to 20 hours. During the cooling process, natural gas is stopped and a vacuum is drawn until the temperature drops to room temperature. The natural gas (the gas source for vapor deposition) is heat-treated at 1200℃ for 15 hours in a high-temperature reactor (equivalent to the vapor deposition process) to obtain a coated crucible (thermal field structure). The coating thickness is 2 mm.

[0111] The coated crucible prepared in Example 1 has an intact, crack-free surface coating with uniformity, no significant color difference, and a smooth, high-quality surface. After nine months of use, the coated crucible showed no significant damage; minor damage to the coating did not affect its continued use, and it continued to provide protection against silicon etching for the internal carbon / carbon crucible.

[0112] Unless otherwise specified, performance testing in this application is conducted using the following method: visual inspection is performed after coating is completed / after use (the grades can also be referred to in Table 1, for example, Table 1 below). Unless otherwise specified, the performance testing methods for the coated crucibles or equivalent thermal field structural components prepared in this application are all conducted using the above methods.

[0113] Table 1 Performance evaluation of coated crucibles

[0114]

[0115] The composition of the raw materials can also be found in Table 2, and the performance evaluation of the coated crucible in Example 1 can also be found in Table 3.

[0116] Table 2. Composition of coating raw materials and key preparation process parameters for Examples 1-6 and Comparative Examples 1-3

[0117]

[0118] Example 2

[0119] The method for preparing the coated carbon / carbon crucible in Example 2 is basically the same as in Example 1, except that the original composition of the coating is different (see Table 2 for further details): The only difference is the ratio of powder A, which is changed to a mass ratio of 500-mesh pyrolytic graphite, 100-mesh flake graphite powder, 500-mesh flake graphite powder, and 10000-mesh flake graphite powder of 2:1:6:1. In this example, the crucible surface coating is intact, without cracks, uniform, without significant color difference, and has a smooth surface with good quality. The coated crucible showed no significant damage after 9 months of use; slight damage to the coating did not affect continued use, and it could still provide protection against silicon etching for the internal carbon / carbon crucible (see Table 3 for further details).

[0120] Example 3

[0121] The method for preparing the coated carbon / carbon crucible in Example 3 is basically the same as in Example 1, except that the original composition of the coating is different (see Table 2 for further details): the mass ratio of powder A and solution A is changed to 1:0.5. In this example, the coating on the crucible surface is intact, without cracks, uniform, and without obvious color difference, but the surface is relatively rough. After 9 months of use, the coated crucible showed no significant damage, although there was some small-area peeling of the coating. However, it can still be used in the thermal field due to the inherent properties of the internal crucible (see Table 3 for further details).

[0122] Example 4

[0123] The method for preparing the coated carbon / carbon crucible in Example 4 is basically the same as in Example 1, except that the original composition of the coating is different (see also Table 2): the only difference from Example 1 is the coating thickness, which is changed to 0.3 mm. In this example, the coating on the crucible surface is intact, without cracks, uniform, without obvious color difference, and the surface is smooth and of good quality. After 9 months of use, the surface of the coated crucible is slightly damaged, the coating is damaged and peels off over a large area, but it can still be used in the thermal field by relying on the internal performance of the crucible itself (see also Table 3).

[0124] Example 5

[0125] The method for preparing the coated carbon / carbon crucible in Example 5 is basically the same as in Example 1, except that the original composition of the coating is different (see Table 2 for further details): the only difference from Example 1 is the holding time at 1200℃, which is changed to 5 hours. In this example, the coating on the surface of the crucible is intact and crack-free, the coating is uniform but has color differences, and the surface is rough. After 9 months of use, the surface of the coated crucible showed small-area patchy peeling, the coating was damaged and peeled off over a large area, but it can still be used in the thermal field by relying on the internal performance of the crucible itself (see Table 3 for further details).

[0126] Example 6

[0127] The method for preparing the coated carbon / carbon crucible in Example 6 is basically the same as in Example 1, except that the original composition of the coating is different (see Table 2 for further details): the only difference from Example 1 is the holding time at 1200℃, which is changed to 20 hours. In this example, the coating on the surface of the crucible is intact and without cracks, but the coating uniformity is poor, there is obvious color difference, and the surface flatness is poor. After 9 months of use, the surface of the coated crucible showed small-area patchy peeling, and the coating was damaged and peeled off over a large area, but it can still be used in the thermal field by relying on the internal performance of the crucible itself (see Table 3 for further details).

[0128] Comparative Example 1

[0129] The method for preparing the coated carbon / carbon crucible in Comparative Example 1 is basically the same as that in Example 1, except that the composition of the coating raw materials is different (see also Table 2); the uncoated carbon / carbon thermal field crucible suffered severe surface corrosion and cracking after 6 months of use, and the product was scrapped (see also Table 3).

[0130] Comparative Example 2

[0131] The method for preparing the coated carbon / carbon crucible in Comparative Example 2 was basically the same as that in Example 1, except that the original composition of the coating was different (see also Table 2). The crucible showed no significant damage after 9 months of use, although the coating exhibited small-area peeling (see also Table 3).

[0132] Comparative Example 3

[0133] The method for preparing the coated carbon / carbon crucible in Comparative Example 3 was basically the same as that in Example 1, except that the original composition of the coating was different (see also Table 2). After 6 months and 9 months of use, small areas of the crucible surface peeled off in chunks, indicating that the coating was damaged and peeled off over a large area (see also Table 3).

[0134] Table 3 Performance evaluation of coated crucibles prepared in Examples 1-6 and at ratios of 1-3

[0135]

[0136] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0137] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A composite coating, characterized in that, The composite coating is bonded to the surface of the carbon / carbon substrate; The composite coating comprises a calcined resin and a graphite-based carbon material, wherein at least a portion of the calcined resin forms a framework with interconnected channels, and at least a portion of the graphite-based carbon material fills the interconnected channels. The graphite-based carbon material includes a first carbon material and a second carbon material; the first carbon material includes flake graphite powder and pyrolytic graphite; the second carbon material includes carbon particles, and the matrix material of the carbon / carbon substrate includes graphite. The method for preparing the composite coating includes the following steps: The first carbon material, polymer resin, and alcohol solvent are mixed to obtain the first slurry; The first slurry is applied to the surface of a carbon / carbon substrate and dried to form a pre-coating bonded to the surface of the carbon / carbon substrate. Under an inert atmosphere, the pre-coating is heat-treated to form a skeleton with interconnected channels in the polymer resin, and the first carbon material is attached to at least a portion of the skeleton to obtain a skeleton coating including graphitic carbon material. In the presence of a precursor material of the second carbon material, the framework coating comprising graphite-based carbon material is subjected to vapor deposition to form a composite coating containing the second carbon material; wherein at least a portion of the second carbon material fills the communicating channels.

2. The composite coating according to claim 1, characterized in that, It meets one or more of the following characteristics: The mass ratio of the flake graphite powder to the pyrolytic graphite is 8:2 to 9.9:0.1; The thickness of the composite coating is 0.3 mm to 3 mm; The density of the composite coating is 1.0 g / cm³. 3 ~1.8g / cm 3 ; The main material of the surface layer in contact with the composite coating in the carbon / carbon substrate is a carbon / carbon composite material; The main material of the carbon / carbon substrate is a carbon / carbon composite material.

3. The method for preparing the composite coating according to claim 1 or 2, characterized in that, Includes the following steps: The first carbon material, polymer resin, and alcohol solvent are mixed to obtain the first slurry; The first slurry is applied to the surface of a carbon / carbon substrate and dried to form a pre-coating bonded to the surface of the carbon / carbon substrate. Under an inert atmosphere, the pre-coating is heat-treated to form a skeleton with interconnected channels in the polymer resin, and the first carbon material is attached to at least a portion of the skeleton to obtain a skeleton coating including graphitic carbon material. In the presence of a precursor material of the second carbon material, the framework coating comprising graphite-based carbon material is subjected to vapor deposition to form a composite coating containing the second carbon material; wherein at least a portion of the second carbon material fills the communicating channels.

4. The preparation method according to claim 3, characterized in that, It meets one or more of the following characteristics: The first carbon material includes flake graphite powder and pyrolytic graphite, wherein the particle size of the flake graphite powder is 100 mesh to 10,000 mesh; and the particle size of the pyrolytic graphite is 100 mesh to 500 mesh. The mass ratio of 500-mesh pyrolytic graphite, 100-mesh flake graphite powder, 500-mesh flake graphite powder and 10000-mesh flake graphite powder in the first carbon material is (0.1~2):(0.1~1):(5~10):(0.1~2).

5. The preparation method according to claim 3, characterized in that, It meets one or more of the following characteristics: The mass ratio of the polymer resin to the alcohol solvent in the first slurry is (85-99):(1-15). The ratio of the mass of the first carbon substance in the first slurry to the sum of the masses of the polymer resin and the alcohol solvent is 1:(0.75~4).

6. The preparation method according to claim 3, characterized in that, In the step of heat-treating the pre-coating under an inert atmosphere to form a skeleton with interconnected channels in the polymer resin, wherein the first carbon material is attached to at least a portion of the skeleton to obtain a skeleton coating comprising graphitic carbon material, the heat treatment temperature is 900℃~1200℃ and the heat treatment time is 2h~20h.

7. The preparation method according to claim 3, characterized in that, In the step of forming a composite coating with the second carbon material by performing vapor deposition on the skeleton coating including the graphite-based carbon material in the presence of the precursor material of the second carbon material, the vapor deposition temperature is 900℃~1400℃ and the time is 5h~50h.

8. A carbon / carbon crucible, characterized in that, The invention includes a carbon / carbon substrate and a composite coating bonded to the surface of the carbon / carbon substrate, wherein the composite coating includes at least one of the composite coatings described in claim 1 or 2 and the composite coatings prepared by the preparation method of any one of claims 3 to 7.

9. The application of the carbon / carbon crucible according to claim 8 in high-temperature processes, wherein, The high-temperature process includes a high-temperature treatment step at 1400℃ to 1800℃.

10. The application of the carbon / carbon crucible according to claim 8 in the preparation of single-crystal silicon, comprising the following steps: placing the carbon / carbon crucible in a thermal field of 1400°C to 1600°C.

Images