Tantalum carbide coating and preparation method thereof

Abstract

The embodiment of the invention provides a tantalum carbide coating and a preparation method thereof. The method comprises the following steps: by taking tantalum carbide as a raw material, generating a first tantalum carbide coating on the surface of a coating carrier through a physical vapor deposition method, a first tantalum source and a first carbon source are selected, and a second tantalum carbide coating is generated on the surface of the first tantalum carbide coating in a second preparation mode; and a second tantalum source and a second carbon source are selected, and a third tantalum carbide coating is generated on the surface of the second tantalum carbide coating through the chemical vapor deposition method. The tantalum carbide coating is prepared by adopting a tantalum carbide coating preparation method. The second tantalum carbide coating is loose and porous and has many defects, the compactness of the second tantalum carbide coating can be improved by preparing the first tantalum carbide coating to guide the second tantalum carbide coating and preparing the third tantalum carbide coating to block pores of the second tantalum carbide coating, and therefore the super-thick compact tantalum carbide coating with the total thickness larger than 200 micrometers is prepared; and the process requirements and the preparation difficulty are greatly reduced.

Description

Technical Field

[0001] The present invention relates to the field of coatings, and in particular to tantalum carbide coatings and preparation methods thereof. Background Art

[0002] Tantalum carbide coatings are highly favored in the field of material processing because of their high temperature resistance, oxidation resistance, corrosion resistance, wear resistance, and impact resistance, which can increase tool life and reduce maintenance costs. The performance of tantalum carbide coatings is affected by their thickness. Thicker tantalum carbide coatings are more wear-resistant and have better performance than thinner tantalum carbide coatings. However, in the preparation of ultra-thick tantalum carbide coatings exceeding 200um, defects such as cracks and pores are easily generated, making the prepared ultra-thick tantalum carbide coatings loose and porous, greatly reducing the performance advantages of ultra-thick tantalum carbide coatings. Increasing the density of ultra-thick tantalum carbide coatings will greatly increase the difficulty of their preparation and the complexity of the preparation process.

[0003] Therefore, it is necessary to provide a tantalum carbide coating and a preparation method thereof, so that the prepared tantalum carbide coating has a large thickness, high density, few defects, good quality, and low process difficulty. Summary of the invention

[0004] One or more embodiments of the present specification provide a method for preparing a tantalum carbide coating. The method includes: using tantalum carbide as a raw material, generating a first tantalum carbide coating on the surface of a coating carrier by a first preparation method, wherein the first preparation method is a physical vapor deposition (PVD) method; selecting a first tantalum source and a first carbon source, generating a second tantalum carbide coating on the surface of the first tantalum carbide coating by a second preparation method; selecting a second tantalum source and a second carbon source, generating a third tantalum carbide coating on the surface of the second tantalum carbide coating by a third preparation method, wherein the third preparation method is a chemical vapor deposition (CVD) method.

[0005] In some embodiments, the sum of the thicknesses of the first tantalum carbide coating, the second tantalum carbide coating, and the third tantalum carbide coating is greater than 200 um.

[0006] In some embodiments, the thickness of the second tantalum carbide coating is greater than the thickness of the first tantalum carbide coating or the thickness of the third tantalum carbide coating, and the thickness of the second tantalum carbide coating is greater than the sum of the thicknesses of the first tantalum carbide coating and the third tantalum carbide coating.

[0007] In some embodiments, the thickness of the first tantalum carbide coating is 0.05 um to 1 um, the thickness of the second tantalum carbide coating is 200 um to 1000 um, and the thickness of the third tantalum carbide coating is 20 um to 80 um.

[0008] In some embodiments, the second preparation method includes one or more of a sol-gel method, a spraying method, an electrophoretic deposition method, a solid phase reaction method, and a self-propagating high temperature synthesis method.

[0009] In some embodiments, the molar ratio of carbon element to tantalum element in the first tantalum source and the first carbon source is 1:(0.7-1.5).

[0010] In some embodiments, the growth rate of the third tantalum carbide coating is 5 um / h to 20 um / h.

[0011] In some embodiments, the first tantalum source includes at least one of tantalum oxide and tantalum isopropoxide, the second tantalum source is tantalum chloride, and the first carbon source and the second carbon source are carbon-containing organic matter.

[0012] In some embodiments, the coating carrier includes one or more of a crucible, a seed crystal holder, a lifting rod, a crystal growth furnace chamber, and a stopper for growing silicon carbide.

[0013] In some embodiments, the method further includes: recovering tantalum-containing waste generated during the preparation of the first tantalum carbide coating, the second tantalum carbide coating, and the third tantalum carbide coating; preparing the tantalum carbide raw material based on the tantalum-containing waste to achieve recycling of tantalum elements during the preparation of the tantalum carbide coating.

[0014] One or more embodiments of the present specification provide a tantalum carbide coating, which is prepared by the method described in the embodiments of the present specification.

[0015] The preparation method of the tantalum carbide coating provided by one or more embodiments of the present specification can combine the advantages of physical vapor deposition (PVD), traditional coating preparation methods (sol-gel method, spraying method, electrophoretic deposition method, solid phase reaction method, or self-propagating high temperature synthesis method) and chemical vapor deposition (CVD) to prepare an ultra-thick (total thickness greater than 200um) and dense tantalum carbide coating with a PVD guide layer + ultra-thick intermediate layer + CVD plugging layer structure. In addition, when only using the traditional coating preparation method to obtain an ultra-thick (total thickness greater than 200um) and dense tantalum carbide coating, there are extremely high requirements for the deposition raw material ratio, deposition process, and coating heat treatment process, and the coating preparation is extremely difficult. In the scheme of the present application, the first tantalum carbide coating prepared by the first preparation method is used to guide the second tantalum carbide coating, and the third tantalum carbide coating prepared by the third preparation method is used to seal the gaps in the second tantalum carbide coating, which can reduce defects such as pores and cracks in the second tantalum carbide coating and improve the density of the second tantalum carbide coating, thereby preparing an ultra-thick (total thickness greater than 200um) and dense tantalum carbide coating, greatly reducing the process requirements and preparation difficulty of preparing the ultra-thick and dense tantalum carbide coating, and enhancing feasibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] This specification will be further described in the form of exemplary embodiments, which will be described in detail by the accompanying drawings. These embodiments are not restrictive, and in these embodiments, the same number represents the same structure, wherein:

[0017] Figure 1 is a flow chart of an exemplary method for preparing a tantalum carbide coating according to some embodiments of the present specification;

[0018] Figure 2 is a schematic diagram of an exemplary tantalum carbide coating structure according to some embodiments of the present specification;

[0019] Figure 3 is a schematic diagram of an exemplary apparatus for growing silicon carbide according to some embodiments of the present specification;

[0020] Figure 4 is a flow chart of an exemplary method for preparing a tantalum carbide coating according to other embodiments of the present specification. DETAILED DESCRIPTION

[0021] In order to more clearly illustrate the technical solutions of the embodiments of this specification, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of this specification. For ordinary technicians in this field, this specification can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0022] It should be understood that the "system", "device", "unit" and / or "module" used herein are a method for distinguishing different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions.

[0023] As shown in this specification and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "comprise" and "include" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0024] Flowcharts are used in this specification to illustrate the operations performed by the system according to the embodiments of this specification. It should be understood that the preceding or following operations are not necessarily performed precisely in order. Instead, the steps may be processed in reverse order or simultaneously. At the same time, other operations may also be added to these processes, or one or more operations may be removed from these processes.

[0025] Figure 1 FIG. 1 is a flow chart of an exemplary method for preparing a tantalum carbide coating according to some embodiments of the present specification. Figure 1 As shown, process 100 includes the following steps.

[0026] Step 110: Using tantalum carbide as a raw material, a first tantalum carbide coating is formed on the surface of a coating carrier by a first preparation method.

[0027] Tantalum carbide (TaC) has a high melting point (3880°C, one of the materials with higher melting points among currently known compounds), high hardness (Mohs hardness 9, close to diamond), excellent thermal stability and chemical stability (stable in strong acid, strong alkali, and strong oxidizing environments), and good electrical and thermal conductivity due to its chemical bond strength and dense crystal structure. These properties make tantalum carbide widely used in aerospace, semiconductor industry and other fields. In some embodiments, tantalum carbide powder can be used as a raw material to generate a first tantalum carbide coating on the surface of a coating carrier by a first preparation method. Compared with bulk solids, tantalum carbide powder has a larger specific surface area, which is conducive to gasification and deposition, making the prepared coating more uniform, increasing process stability and improving the density of the prepared coating.

[0028] The first preparation method refers to a method that can prepare the first tantalum carbide coating. In some embodiments, the first preparation method is a physical vapor deposition (PVD) method. Physical vapor deposition refers to a method of using a physical method to vaporize a material source (solid or liquid) into gaseous molecules and deposit them on the surface of a substrate to form a coating. Exemplarily, the tantalum carbide raw material can be vaporized into molecules by evaporation, sublimation or sputtering, and deposited on the surface of the substrate to form a tantalum carbide coating. Commonly used physical vapor deposition methods include vacuum evaporation, magnetron sputtering, arc ion plating / deposition, etc. In some embodiments, tantalum carbide powder ground to a certain particle size can be heated to a sublimation temperature to convert tantalum carbide from a solid phase to a gas phase, and the gas phase tantalum carbide is deposited on the surface of the coating carrier in a vacuum environment to form a first tantalum carbide coating. The certain particle size can be set based on experience or the needs of the first preparation method.

[0029] The preparation process of the physical vapor deposition method is simple, and the obtained tantalum carbide coating has few impurities and voids, high density and high bonding strength with the coating carrier, so that the generated first tantalum carbide coating is firmly bonded to the surface of the coating carrier, reducing the risk of the tantalum carbide coating falling off during use.

[0030] Figure 2 is a schematic diagram of an exemplary tantalum carbide coating structure according to some embodiments of the present specification. The coating carrier refers to an object to be coated with a coating. For example, Figure 2 The coating carrier 210 in the embodiment of the present invention can be coated with a coating to increase the function or performance of the coating carrier. For example, the coating carrier coated with a tantalum carbide coating can improve its high temperature resistance, corrosion resistance, oxidation resistance, wear resistance, thermal conductivity and impact resistance. The coating carrier can be metal, non-metal or other materials.

[0031] In some embodiments, the coating support includes an apparatus or component for growing silicon carbide. For example, Figure 3 Schematic diagram of an exemplary device for growing silicon carbide according to some embodiments of this specification. Figure 3 As shown, the equipment for growing silicon carbide may include a crucible 310, a seed crystal holder 320, a lifting rod 330, a furnace 340, etc. The crucible 310 is a component for placing the melt required for the growth of silicon carbide crystals. When the melt in the crucible 310 is in full contact with the silicon carbide seed crystal, the melt can be adsorbed on the surface of the silicon carbide seed crystal and grow along the seed crystal lattice to form a silicon carbide crystal. The seed crystal holder 320 is a component for fixing the silicon carbide seed crystal. The seed crystal holder 320 may be provided with a seed crystal bonding surface on the side in contact with the melt, and the silicon carbide seed crystal can be bonded to the seed crystal bonding surface and contact the melt in the crucible to generate silicon carbide crystals. The lifting rod 330 is a component for providing support and motion control. The lifting rod 330 is usually located above the crucible containing the melt, and its lower end is connected to the seed crystal holder 320. The growth of silicon carbide crystals is achieved by controlling the rotation and lifting movement of the lifting rod. The furnace 340 is a component that provides a place for the growth of silicon carbide crystals, and can accommodate a plurality of components required for the growth of crystals (eg, the crucible 310 , the seed crystal holder 320 , and the lifting rod 330 ).

[0032] The apparatus for growing silicon carbide may further include a stopper ( Figure 3 The limiter is a device used to limit the range of movement of equipment or components. By limiting the range of movement of the silicon carbide crystal growth equipment or components during operation, the safe operation of the equipment is ensured.

[0033] In some embodiments, the coating carrier includes one or more of a crucible, a seed crystal holder, a lifting rod, a crystal growth furnace hearth, and a stopper for growing silicon carbide. As a focal material in the semiconductor field, silicon carbide has a melting point of up to 2700°C, which places extremely high demands on its crystal growth equipment and has extremely high usage losses. By coating tantalum carbide coatings on the surfaces of crucibles, seed crystal holders, lifting rods, crystal growth furnace hearths, and stoppers used to grow silicon carbide, the high temperature resistance, chemical stability, wear resistance, and corrosion resistance of these components can be increased, effectively extending their service life and reducing loss costs.

[0034] The first tantalum carbide coating refers to the first layer of tantalum carbide coating on the surface of the coating carrier. For example, Figure 2The first tantalum carbide coating 220 in the embodiment of the present invention. The first tantalum carbide coating generated by the first preparation method is equivalent to a dense guide layer, which has a strong bonding force with the coating carrier and can guide the subsequent crystallization of the second tantalum carbide coating, thereby improving the density and flatness of the crystallization of the second tantalum carbide coating and the bonding force with the first tantalum carbide coating, reducing the risk of the tantalum carbide coating falling off during use, and reducing the difficulty of subsequently blocking the pores of the second tantalum carbide coating by the third preparation method.

[0035] Step 120: Select a first tantalum source and a first carbon source, and generate a second tantalum carbide coating on the surface of the first tantalum carbide coating by a second preparation method.

[0036] The second preparation method refers to a method for preparing the second tantalum carbide coating. In some embodiments, the second preparation method may include one or more of a sol-gel method, a spraying method, an electrophoretic deposition method, a solid phase reaction method, and a self-propagating high temperature synthesis method.

[0037] The sol-gel method refers to a method in which a metal organic or inorganic compound is solidified through a solution, sol, or gel, and then heat-treated to form a solid oxide or other compound. For example, based on a first carbon source and a first tantalum source, a precursor solution containing tantalum and carbon is first prepared on the surface of a first tantalum carbide coating by a chemical route, converted into a solid through a sol-gel process, and then sintered and carbonized at high temperature to obtain a second tantalum carbide coating.

[0038] The spraying method refers to a method of spraying a liquid compound to be sprayed onto the surface of a substrate through a high-speed airflow to form a coating. For example, a spraying liquid is prepared by mixing a first carbon source, a first tantalum source, an organic solvent, etc., and a second tantalum carbide coating is formed on the surface of the first tantalum carbide coating by spraying or brushing.

[0039] Electrophoretic deposition refers to a method of depositing charged nanoparticles or ions in a dispersion on a substrate using an external electric field to form a coating. For example, a suspension is prepared by mixing a first carbon source, a first tantalum source, an organic solvent, etc., and the suspension is placed in an electrophoretic deposition device. The charged carbon ions and tantalum ions are moved to the electrode by an external electric field and react and deposit on the surface of the first tantalum carbide coating to form a second tantalum carbide coating.

[0040] The solid phase reaction method refers to the process in which a solid and a solid react to form a new solid product. For example, a solid first carbon source and a solid first tantalum source (such as carbon powder and tantalum pentoxide powder) are evenly coated on the surface of a first tantalum carbide coating and sintered to form a second tantalum carbide coating through a solid phase reaction.

[0041] The self-propagating high temperature synthesis method refers to a method in which a material with a sufficiently high heat of generation is used to convert reactants into products through the self-propagation of a combustion wave after ignition. For example, the first carbon source and the first tantalum source are fully mixed and pressed into shape (i.e., material) on the surface of the first tantalum carbide coating, and the material is ignited by an external heat source to initiate a chemical reaction. The heat of generation is used to rapidly increase the temperature of the adjacent material and continue to initiate a new chemical reaction until all the materials react completely to form a second tantalum carbide coating.

[0042] Compared with the first preparation method and the third preparation method, by selecting one or more of the sol-gel method, the spraying method, the electrophoretic deposition method, the solid phase reaction method, and the self-propagating high temperature synthesis method as the second preparation method, a second tantalum carbide coating with a higher thickness can be prepared quickly, at a low cost, and at a high conversion rate. It can be understood that although the second preparation method can efficiently prepare a second tantalum carbide coating with a higher thickness, it is generally loose and porous, and the structure is not dense enough. In the present application, the first tantalum carbide coating prepared by the first preparation method guides the second tantalum carbide coating, and the third tantalum carbide coating prepared by the third preparation method blocks the gaps in the second tantalum carbide coating, which can reduce defects such as pores and cracks in the second tantalum carbide coating, and improve the density of the second tantalum carbide coating, thereby preparing an ultra-thick and dense tantalum carbide coating.

[0043] The traditional method of obtaining ultra-thick (total thickness greater than 200um) and dense tantalum carbide coatings through sol-gel method, spraying method, electrophoretic deposition method, solid phase reaction method, or self-propagating high temperature synthesis method has extremely high requirements for the ratio of deposition raw materials, deposition process, and coating heat treatment process, and the coating preparation is extremely difficult. In comparison, the solution of this application greatly reduces the process requirements for preparing ultra-thick (total thickness greater than 200um) and dense tantalum carbide coatings, reduces the difficulty of preparation, and is more feasible.

[0044] It can be understood that tantalum carbide is a carbide of tantalum, and its raw materials need to include a tantalum source that provides tantalum elements and a carbon source that provides carbon elements. The first tantalum source refers to a raw material containing tantalum elements for generating the second tantalum carbide coating. The first carbon source refers to a raw material containing carbon elements for generating the second tantalum carbide coating. In some embodiments, the first tantalum source may include at least one of tantalum oxide and tantalum isopropoxide. For example, the first tantalum source may be tantalum pentoxide, tantalum pentaisopropoxide, etc. In some embodiments, the first carbon source may be a carbon-containing organic matter. For example, the first carbon source may be polyvinyl alcohol, graphite, hydrocarbon compounds, etc.

[0045] In some embodiments, the selection of the first tantalum source and the first carbon source may be related to the second preparation method. The first tantalum source and the first carbon source should be selected to match the second preparation method as much as possible. For example, when the second preparation method is a sol-gel method, the first tantalum source may be tantalum isopropoxide, and the first carbon source may be polyvinyl alcohol. For another example, when the second preparation method is a solid phase reaction method, the first tantalum source may be tantalum oxide, and the first carbon source may be carbon black, etc.

[0046] By selecting at least one of tantalum oxide and tantalum isopropoxide as the first tantalum source and carbon-containing organic matter as the first carbon source, the second preparation method can be adapted to obtain a second tantalum carbide coating through reaction.

[0047] In some embodiments, the molar ratio of carbon element to tantalum element in the first tantalum source and the first carbon source is 1:(0.7-1.5). Preferably, the molar ratio of carbon element to tantalum element in the first tantalum source and the first carbon source can also be 1:1. It can be understood that the ratio of carbon to tantalum element in the molecular formula of tantalum carbide is 1:1. When preparing the tantalum carbide coating, the molar ratio of carbon element to tantalum element in the first tantalum source and the first carbon source should also be about 1:1 for best results. If the proportion of tantalum element is too high, the first tantalum source will not react completely, and the carbon element in the first tantalum carbide coating will also react during the preparation process, resulting in loss of the first tantalum carbide coating; if the proportion of carbon element is too high, the first carbon source will not react completely, and too much carbon will be embedded in the generated second tantalum carbide coating to cause defects, resulting in looseness of the second tantalum carbide coating, increasing the internal stress of the second tantalum carbide coating, and easy to crack when subjected to external force. By setting the molar ratio of carbon to tantalum in the first tantalum source and the first carbon source to 1:(0.7-1.5), and the preferred molar ratio of carbon to tantalum in the first tantalum source and the first carbon source to 1:1, the ratio of carbon to tantalum can be made approximately the same, and the first tantalum source and the first carbon source react completely to generate a high-quality second tantalum carbide coating. In addition, in the formula of the embodiment of this specification, as long as the molar ratio of carbon to tantalum meets the requirements, there is no requirement for concentration, which reduces the process difficulty of raw material ratio.

[0048] In some embodiments, a certain mass of the first carbon source, the first tantalum source, and an organic solvent (such as ethanol, etc.) can be mixed to prepare a spray liquid, and the spray liquid is evenly sprayed on the surface of the first tantalum carbide coating away from the coating carrier using a spraying device at a certain temperature, and the first tantalum carbide coating is placed in a high-temperature treatment device, and an inert gas is introduced into the high-temperature treatment device to sinter and obtain a second tantalum carbide coating. The certain mass and the certain temperature can be set based on experience or the requirements of the second preparation method.

[0049] The second tantalum carbide coating refers to the second tantalum carbide coating on the surface of the coating carrier. For example, Figure 2The second tantalum carbide coating 230 in the second preparation method is thicker than other layers, but has relatively larger structural defects and needs to be improved by other layers.

[0050] Step 130: Select a second tantalum source and a second carbon source, and generate a third tantalum carbide coating on the surface of the second tantalum carbide coating by a third preparation method.

[0051] The second tantalum source refers to a raw material containing tantalum elements for generating the third tantalum carbide coating. The second carbon source refers to a raw material containing carbon elements for generating the third tantalum carbide coating. In some embodiments, the second tantalum source may be tantalum chloride. For example, the second tantalum source may be tantalum pentachloride. In some embodiments, the second carbon source may be a carbon-containing organic matter. For example, the second carbon source may be polyvinyl alcohol, graphite, hydrocarbon compounds, etc. By selecting tantalum pentachloride as the second tantalum source and carbon-containing organic matter as the second carbon source, the third preparation method can be adapted to obtain the third tantalum carbide coating by reaction.

[0052] The third preparation method refers to a method that can prepare the third tantalum carbide coating. In some embodiments, the third preparation method is a chemical vapor deposition (CVD) method. Chemical vapor deposition refers to a method of using one or more gas phase compounds or single substances containing the elements required for the coating to chemically react and deposit on the surface of the substrate to form a coating. Exemplarily, the chemical vapor deposition method can be achieved by chemically reacting and depositing the second tantalum source gas and the second carbon source gas at high temperature.

[0053] In some embodiments, an inert gas may be introduced into a high temperature processing device, and a coating carrier with a first tantalum carbide coating and a second tantalum carbide coating may be placed therein; the second carbon source and the second tantalum source may be gasified and introduced into the high temperature processing device with an auxiliary gas (such as hydrogen, nitrogen, etc.) to react, and a third tantalum carbide coating may be deposited on the surface of the second tantalum carbide coating at a certain growth rate. The growth rate refers to a parameter indicating the thickness growth of the tantalum carbide coating per unit time. The certain growth rate may be set based on experience or the requirements of the third preparation method.

[0054] The third tantalum carbide coating prepared by chemical vapor deposition grows on the surface of the second tantalum carbide coating, and can block the pores of the second tantalum carbide coating during deposition, making the second tantalum carbide coating more dense. In addition, the preparation process of chemical vapor deposition is simple, and the obtained third tantalum carbide coating has few impurities and voids, high density and high bonding strength with the second tantalum carbide coating, so that the generated third tantalum carbide coating blocks the voids of the second tantalum carbide coating and is firmly bonded to the second tantalum carbide coating.

[0055] In some embodiments, the growth rate of the third tantalum carbide coating can be 5um / h to 20um / h. It is understandable that if the growth rate of the third tantalum carbide coating is too slow (such as less than 5um / h), the third tantalum carbide coating may only penetrate the pores of the second tantalum carbide coating during deposition, but fail to block the pores; if the growth rate of the third tantalum carbide coating is too fast (such as greater than 20um / h), the blocking depth of the pores of the second tantalum carbide coating during deposition of the third tantalum carbide coating may be insufficient. By setting the growth rate of the third tantalum carbide coating to 5um / h to 20um / h, the blocking effect of the pores of the second tantalum carbide coating during deposition of the third tantalum carbide coating can be better, so as to improve the structural defects of the second tantalum carbide coating.

[0056] The third tantalum carbide coating refers to the third tantalum carbide coating on the surface of the coating carrier. For example, Figure 2 The third tantalum carbide coating 240 is prepared by the third method and deposits and grows on the surface of the second tantalum carbide coating. During deposition, the pores on the surface of the second tantalum carbide coating can be blocked, making the second tantalum carbide coating more compact.

[0057] In some embodiments, the sum of the thicknesses of the first tantalum carbide coating, the second tantalum carbide coating, and the third tantalum carbide coating is greater than 200um. It is understandable that the purpose of preparing the tantalum carbide coating is to protect the coating carrier. Under the same conditions, the thicker the thickness of the tantalum carbide coating, the higher the number of chemical reactions such as oxidation and pyrolysis that it can withstand. By preparing a tantalum carbide coating with a total thickness greater than 200um, the number of chemical reactions that the tantalum carbide coating can withstand can be increased, effectively reducing the adverse effects such as cracking caused by loss, extending the service life, and enhancing the protective effect. In some embodiments, the thickness of the first tantalum carbide coating, the second tantalum carbide coating, and the third tantalum carbide coating can be 200um to 1000um. While maintaining a relatively thick thickness, avoid the decrease in adhesion between the tantalum carbide coating and the coating carrier due to excessive thickness, causing the coating to peel off and crack.

[0058] In some embodiments, the thickness of the second tantalum carbide coating may be greater than the thickness of the first tantalum carbide coating or the thickness of the third tantalum carbide coating, and the thickness of the second tantalum carbide coating may be greater than the sum of the thicknesses of the first tantalum carbide coating and the third tantalum carbide coating. It is understandable that, through the first preparation method and the third preparation method, if you want to prepare an ultra-thick tantalum carbide coating (thickness greater than 200um), higher process conditions and costs are required, and the growth rate is slow, and it is not easy to meet the thickness requirements. The second preparation method can prepare an ultra-thick tantalum carbide coating (thickness greater than 200um) efficiently and at low cost. Therefore, the thickness of the second tantalum carbide coating is set to be the thickest, which is greater than the thickness of the first tantalum carbide coating, the thickness of the third tantalum carbide coating and their sum.

[0059] In some embodiments, the thickness of the first tantalum carbide coating is 0.05um to 1um. If the thickness of the first tantalum carbide coating is too low (e.g., less than 0.05um), it is difficult to achieve the guiding effect on the second tantalum carbide coating; if the thickness of the first tantalum carbide coating is too high (e.g., greater than 1um), the growth rate of the first preparation method is limited, and the growth process of the first tantalum carbide coating is slow and takes a long time. Preferably, the thickness of the first tantalum carbide coating can be 0.05um to 0.3um.

[0060] In some embodiments, the thickness of the second tantalum carbide coating is 200um to 1000um. Since the thickness is mainly provided by the second tantalum carbide coating, if the thickness of the second tantalum carbide coating is too low (such as less than 200um), it is easy to cause the total thickness to fail to meet the standard (not to be super thick), affecting the overall quality of the tantalum carbide coating; if the thickness of the second tantalum carbide coating is too high (such as higher than 1000um), it reduces the adhesion of the second tantalum carbide coating and causes unnecessary process waste.

[0061] In some embodiments, the thickness of the third tantalum carbide coating is 20 um to 80 um. The thickness of the third tantalum carbide coating depends on the aforementioned growth rate and the required plugging time, so as to achieve the best plugging effect on the second tantalum carbide coating.

[0062] In some embodiments of the present specification, by setting the thickness of the first tantalum carbide coating to 0.05um~1um, the thickness of the second tantalum carbide coating to 200um~1000um, and the thickness of the third tantalum carbide coating to 20um~80um, the main target effects of each layer (i.e., the guiding effect of the first tantalum carbide coating, the thickening effect of the second tantalum carbide coating, and the blocking effect of the third tantalum carbide coating) can be achieved, and a dense and thicker tantalum carbide coating can be generated in coordination.

[0063] In some embodiments of the present specification, a first tantalum carbide coating is generated on the surface of a coating carrier by a first preparation method (physical vapor deposition) using tantalum carbide as a raw material; a second tantalum carbide coating is generated on the surface of the first tantalum carbide coating by a second preparation method (sol-gel method, spraying method, electrophoretic deposition method, solid phase reaction method, and / or self-propagating high temperature synthesis method) using a first tantalum source and a first carbon source; a third tantalum carbide coating is generated on the surface of the second tantalum carbide coating by a third preparation method (chemical vapor deposition method) using a second tantalum source and a second carbon source. The advantages of physical vapor deposition, traditional coating preparation methods (sol-gel method, spraying method, electrophoretic deposition method, solid phase reaction method, or self-propagating high temperature synthesis method) and chemical vapor deposition method can be combined to prepare an ultra-thick (total thickness greater than 200um) and dense tantalum carbide coating having a PVD guide layer + ultra-thick intermediate layer + CVD blocking layer structure.

[0064] The traditional method of obtaining an ultra-thick (total thickness greater than 200um) and dense tantalum carbide coating by a preparation process of sol-gel method, spraying method, electrophoretic deposition method, solid phase reaction method, or self-propagating high temperature synthesis method has extremely high requirements for the ratio of deposition raw materials, deposition process, and coating heat treatment process, and the coating preparation is extremely difficult. In contrast, the scheme of the present application guides the second tantalum carbide coating by the first preparation method, and the third tantalum carbide coating prepared by the third preparation method blocks the gaps in the second tantalum carbide coating, which can reduce the defects such as pores and cracks in the second tantalum carbide coating, and improve the density of the second tantalum carbide coating, thereby preparing an ultra-thick (total thickness greater than 200um) and dense tantalum carbide coating, greatly reducing the process requirements for preparing an ultra-thick and dense tantalum carbide coating, reducing the difficulty of preparation, and making it more feasible.

[0065] An exemplary method 1 for preparing a tantalum carbide coating may include the following steps (S1 corresponds to the aforementioned step 110, S2 to S5 correspond to the aforementioned step 120, and S6 corresponds to the aforementioned step 130):

[0066] S1. Use grinding equipment (such as a ball mill, etc.) to obtain fully ground dry tantalum carbide powder (the particle size is set based on demand or experience), and deposit the tantalum carbide powder on the surface of a graphite disc (i.e., a coating carrier) through high-energy electron beam evaporation technology (i.e., physical vapor deposition) to obtain a first tantalum carbide coating with a thickness of 0.05um to 1um.

[0067] S2. Dispersing tantalum pentaisopropoxide (i.e., the first tantalum source) and polyvinyl alcohol (i.e., the first carbon source) in isopropanol (i.e., an organic solvent), adding nitric acid and ammonia water to mix, and preparing a sol containing the first carbon source and the first tantalum source, wherein the molar ratio of the tantalum element in tantalum pentaisopropoxide to the carbon element in polyvinyl alcohol is 1:1.

[0068] S3. Spin-coat the sol on the surface of the first tantalum carbide coating with a single spin-coating thickness, dry it in a drying device (such as an oven), and repeat the coating and drying for a certain number of times to obtain a second tantalum carbide coating to be treated, wherein the drying device temperature is 80°C to 150°C, the drying time is 1h to 5h, the certain number of times is 6 to 10 times, and the single spin-coating thickness is 34um to 60um; it can be understood that if the single spin-coating thickness is too thin (such as less than 34um), in order to achieve the thickness requirement of the second tantalum carbide coating, it is necessary to repeat more times, which increases the complexity of the process; if the single spin-coating thickness is too thick (such as higher than 60um), the process stability is low, which is prone to increase defects.

[0069] S4. Inert gas is introduced into the high-temperature treatment equipment, and the graphite disc with the second tantalum carbide coating to be treated is placed into the high-temperature treatment equipment (such as a vacuum furnace, etc.), and a first sintering is performed at a first sintering temperature to obtain a pretreated second tantalum carbide coating, wherein the first sintering temperature is 300°C to 600°C, the heating rate to reach the first sintering temperature is 0.5°C / min to 5°C / min, the sintering time of the first sintering is 1h to 6h, and the cooling rate after the first sintering is 20°C / min to 100°C / min.

[0070] S5. Place the graphite disc with the pretreated second tantalum carbide coating into a high-temperature treatment device, and perform a second sintering at a second sintering temperature to obtain a second tantalum carbide coating with a thickness of 204um-600um, wherein the second sintering temperature is higher than the first sintering temperature, which is 1000°C to 1500°C, the heating rate to reach the second sintering temperature is 1°C / min to 10°C / min, the sintering time of the second sintering is 3h to 5h, and the cooling rate after the second sintering is 20°C / min to 100°C / min; it can be understood that the role of the first sintering is to make the sol of the second tantalum carbide coating more closely bonded to the first tantalum carbide coating, and the role of the second sintering is to achieve a phase transition of the second tantalum carbide coating.

[0071] S6. Tantalum pentachloride (i.e., the second tantalum source), ethylene (i.e., the second carbon source), hydrogen, and nitrogen (i.e., the auxiliary gas) are reacted by chemical vapor deposition and deposited on the surface of the second tantalum carbide coating at a growth rate of 5um / h to 20um / h to obtain a third tantalum carbide coating with a thickness of 20-80um.

[0072] An exemplary method 2 for preparing a tantalum carbide coating may include the following steps (S1 corresponds to the aforementioned step 110, S2 to S4 correspond to the aforementioned step 120, and S5 corresponds to the aforementioned step 130):

[0073] S1. Use grinding equipment (such as a ball mill, etc.) to obtain fully ground dry tantalum carbide powder (the particle size is set based on demand or experience), and deposit the tantalum carbide powder on the surface of a graphite disc (i.e., a coating carrier) through high-energy electron beam evaporation technology (i.e., physical vapor deposition) to obtain a first tantalum carbide coating with a thickness of 0.05um to 1um.

[0074] S2. Disperse tantalum pentoxide (i.e., the second tantalum source), tantalum pentaisopropoxide (i.e., the second tantalum source), and polyvinyl alcohol (i.e., the second carbon source) in ethanol to obtain a spray liquid, wherein the molar ratio of the tantalum element in tantalum pentoxide and tantalum pentaisopropoxide to the carbon element in polyvinyl alcohol is 1:1, and the mass fraction of tantalum pentoxide in the second tantalum source is 1% to 5%. It can be understood that tantalum pentoxide has good melt fluidity and has a role equivalent to that of a solvent under high temperature conditions, thereby increasing the fluidity of the formulation system and making the prepared tantalum carbide coating denser.

[0075] S3. Place the graphite disc with the first tantalum carbide coating on a heating device (such as a constant temperature heating plate, etc.) for heating, and use a spraying device (such as an ultrasonic nozzle, etc.) to evenly spray the spray liquid prepared in S2 on the surface of the first tantalum carbide coating to obtain a second tantalum carbide coating to be treated, wherein the heating temperature of the heating device is 80°C-120°C, the single-layer spraying thickness is 5um, and the total spraying thickness is 200um.

[0076] S4. Inert gas is introduced into a high-temperature treatment device (such as a vacuum furnace, etc.), and the graphite disc with the second tantalum carbide coating to be treated is placed into the high-temperature treatment device, and sintered to obtain a second tantalum carbide coating with a thickness of 200 um, wherein the sintering temperature is 1300°C to 2100°C, the heating rate to reach the sintering temperature is 1°C / min to 10°C / min, the sintering time is 3h to 8h, and the cooling rate after sintering is about 20°C / min-100°C / min.

[0077] S5. Tantalum pentachloride (i.e., the second tantalum source), ethylene (i.e., the second carbon source), hydrogen, and nitrogen (i.e., the auxiliary gas) are reacted by chemical vapor deposition and deposited on the surface of the second tantalum carbide coating at a growth rate of 5um / h to 20um / h to obtain a third tantalum carbide coating with a thickness of 20-80um. On this basis, S2-S5 can be repeated to achieve thickness superposition (thickness superposition of the second tantalum carbide coating and the third tantalum carbide coating) until the required total thickness of the tantalum carbide coating is achieved.

[0078] In some embodiments, the method for preparing the tantalum carbide coating may further include recycling tantalum-containing waste generated during the preparation of the first tantalum carbide coating, the second tantalum carbide coating, and the third tantalum carbide coating; preparing tantalum carbide raw materials based on the tantalum-containing waste to achieve the recycling of tantalum elements during the preparation of the tantalum carbide coating. For more information on achieving recycling, please refer to Figure 4 and its related description.

[0079] Figure 4 is an exemplary flow chart of a method for preparing a tantalum carbide coating according to other embodiments of this specification. Figure 4 As shown, process 400 includes the following steps.

[0080] Step 410: Using tantalum carbide as a raw material, a first tantalum carbide coating is formed on the surface of a coating carrier by a first preparation method.

[0081] Step 420: Select a first tantalum source and a first carbon source, and generate a second tantalum carbide coating on the surface of the first tantalum carbide coating by a second preparation method.

[0082] Step 430: Select a second tantalum source and a second carbon source, and generate a third tantalum carbide coating on the surface of the second tantalum carbide coating by a third preparation method.

[0083] For more information about steps 410 to 430, see Figure 1 The relevant descriptions of steps 110 to 130 are not repeated here.

[0084] Step 440, recovering tantalum-containing waste generated during the preparation of the first tantalum carbide coating, the second tantalum carbide coating, and the third tantalum carbide coating.

[0085] Tantalum-containing waste refers to waste containing tantalum elements generated during the preparation of tantalum carbide coatings. In some embodiments, tantalum-containing waste may include tantalum pentachloride, tantalum carbide, tantalum pentoxide, tantalum element and carbon element. Tantalum pentachloride may be derived from a second tantalum source. Tantalum carbide, tantalum pentoxide, tantalum element and carbon element may be derived from byproducts generated in the preparation of a third tantalum carbide coating by chemical vapor deposition, impurities in raw materials, etc. In some embodiments, the waste materials remaining after the tantalum carbide coating is generated may be directly collected to achieve the recovery of tantalum-containing waste.

[0086] Step 450, preparing tantalum carbide raw materials based on tantalum-containing waste, so as to realize the recycling of tantalum elements in the process of preparing tantalum carbide coating.

[0087] In some embodiments, the product of the reaction between tantalum-containing waste and water is oxidized by high-temperature treatment and then reduced to tantalum carbide, thereby achieving the recycling of tantalum elements in the preparation process of tantalum carbide coating.

[0088] In some embodiments of the present specification, by recycling the tantalum-containing waste generated during the preparation of the first tantalum carbide coating, the second tantalum carbide coating and the third tantalum carbide coating; preparing tantalum carbide raw materials based on the tantalum-containing waste, and realizing the recycling of tantalum elements in the preparation of tantalum carbide coatings, tantalum-containing waste can be safely, conveniently and at low cost to solve the storage and treatment problems of toxic tantalum-containing waste, and at the same time realize the recycling of tantalum elements.

[0089] One or more embodiments of the present specification provide a tantalum carbide coating. The tantalum carbide coating is prepared by the preparation method of the tantalum carbide coating described in the embodiments of the present specification.

[0090] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of this specification. Although not explicitly stated here, those skilled in the art may make various modifications, improvements and corrections to this specification. Such modifications, improvements and corrections are suggested in this specification, so such modifications, improvements and corrections still belong to the spirit and scope of the exemplary embodiments of this specification.

[0091] At the same time, this specification uses specific words to describe the embodiments of this specification. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of this specification. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of this specification can be appropriately combined.

[0092] In addition, unless explicitly stated in the claims, the order of the processing elements and sequences described in this specification, the use of alphanumeric characters, or the use of other names are not intended to limit the order of the processes and methods of this specification. Although the above disclosure discusses some invention embodiments that are currently considered useful through various examples, it should be understood that such details are only for illustrative purposes, and the attached claims are not limited to the disclosed embodiments. On the contrary, the claims are intended to cover all modifications and equivalent combinations that are consistent with the essence and scope of the embodiments of this specification. For example, although the system components described above can be implemented by hardware devices, they can also be implemented only by software solutions, such as installing the described system on an existing server or mobile device.

[0093] Similarly, it should be noted that in order to simplify the description disclosed in this specification and thus help understand one or more embodiments of the invention, in the above description of the embodiments of this specification, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the subject matter of this specification are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0094] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of this specification are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0095] Each patent, patent application, patent application publication, and other materials, such as articles, books, specifications, publications, documents, etc., cited in this specification are hereby incorporated by reference in their entirety. Except for application history documents that are inconsistent with or conflicting with the contents of this specification, documents that limit the broadest scope of the claims of this specification (currently or later attached to this specification) are also excluded. It should be noted that if the descriptions, definitions, and / or use of terms in the materials attached to this specification are inconsistent or conflicting with the contents described in this specification, the descriptions, definitions, and / or use of terms in this specification shall prevail.

[0096] Finally, it should be understood that the embodiments described in this specification are only used to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, as an example and not a limitation, alternative configurations of the embodiments of this specification may be considered consistent with the teachings of this specification. Accordingly, the embodiments of this specification are not limited to the embodiments explicitly introduced and described in this specification.

Claims

1. A method for preparing a tantalum carbide coating, characterized in that: The method comprises: Using tantalum carbide as a raw material, a first tantalum carbide coating is formed on the surface of a coating carrier by a first preparation method, wherein the first preparation method is a physical vapor deposition (PVD) method; Selecting a first tantalum source and a first carbon source, and forming a second tantalum carbide coating on the surface of the first tantalum carbide coating by a second preparation method; A second tantalum source and a second carbon source are selected to form a third tantalum carbide coating on the surface of the second tantalum carbide coating through a third preparation method, wherein the third preparation method is a chemical vapor deposition (CVD) method.

2. The method according to claim 1, characterized in that The total thickness of the first tantalum carbide coating, the second tantalum carbide coating and the third tantalum carbide coating is greater than 200 um.

3. The method according to claim 2, characterized in that The thickness of the second tantalum carbide coating is greater than the thickness of the first tantalum carbide coating or the thickness of the third tantalum carbide coating, and the thickness of the second tantalum carbide coating is greater than the sum of the thicknesses of the first tantalum carbide coating and the third tantalum carbide coating.

4. The method according to claim 3, characterized in that The thickness of the first tantalum carbide coating is 0.05um-1um, the thickness of the second tantalum carbide coating is 200um-1000um, and the thickness of the third tantalum carbide coating is 20um-80um.

5. The method according to claim 1, characterized in that The second preparation method includes one or more of a sol-gel method, a spraying method, an electrophoretic deposition method, a solid phase reaction method, and a self-propagating high temperature synthesis method.

6. The method according to claim 5, characterized in that The molar ratio of carbon element to tantalum element in the first tantalum source and the first carbon source is 1:(0.7-1.5).

7. The method according to claim 1, characterized in that The growth rate of the third tantalum carbide coating is 5um / h to 20um / h.

8. The method according to claim 1, characterized in that The first tantalum source includes at least one of tantalum oxide and tantalum isopropoxide, the second tantalum source is tantalum chloride, and the first carbon source and the second carbon source are carbon-containing organic matter.

9. The method according to claim 1, characterized in that: The coating carrier includes one or more of a crucible, a seed crystal holder, a lifting rod, a crystal growth furnace chamber, and a limiting member for growing silicon carbide.

10. The method according to claim 1, characterized in that The method further comprises: Recycling tantalum-containing waste generated during the preparation of the first tantalum carbide coating, the second tantalum carbide coating, and the third tantalum carbide coating; and The tantalum carbide raw material is prepared based on the tantalum-containing waste to achieve the recycling of tantalum elements in the preparation process of tantalum carbide coating.

11. A tantalum carbide coating, characterized in that: The method according to any one of claims 1 to 10 is used to prepare the present invention.

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