Preparation method for tantalum-containing coating, and recycling and reuse method for tantalum-containing waste generated during preparation of tantalum-containing coating

Abstract

Embodiments of the present specification provide a preparation method for a tantalum-containing coating, and a recycling and reuse method for tantalum-containing waste generated during preparation of the tantalum-containing coating. The preparation method comprises: using tantalum carbide as a raw material, and forming a first tantalum carbide coating on a surface of a coating substrate by a physical vapor deposition method; selecting a first tantalum source and a first carbon source, and forming a second tantalum carbide coating on a surface of the first tantalum carbide coating by a second preparation method; and selecting a second tantalum source and a second carbon source, and forming a third tantalum carbide coating on a surface of the second tantalum carbide coating by a chemical vapor deposition method. The recycling and reuse method comprises: adding pure water to tantalum-containing waste to obtain a mixture; adding an alkaline solution to the mixture to obtain a precipitate; filtering, washing, and drying the precipitate to obtain a target precipitate; grinding the target precipitate to obtain a powder; and introducing a first target gas into a high-temperature treatment apparatus, and reacting the powder under high-temperature conditions for a certain period of time to obtain tantalum pentoxide powder.

Description

Methods for preparing tantalum-containing coatings and methods for recycling tantalum-containing waste generated during the preparation of tantalum-containing coatings. Cross-references

[0001] This application claims priority to Chinese application No. 202411930279.3, filed on December 25, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This specification relates to the field of tantalum-containing coating preparation, and in particular to methods for preparing tantalum-containing coatings and methods for recycling and reusing tantalum-containing waste generated during the preparation of tantalum-containing coatings. Background Technology

[0003] Tantalum carbide coatings are highly favored in the materials processing field due to their high-temperature resistance, oxidation resistance, corrosion resistance, wear resistance, and impact resistance, which can improve tool life and reduce maintenance costs. The performance of tantalum carbide coatings is affected by their thickness; thicker coatings are more wear-resistant and perform better than thinner ones. However, in the preparation of ultra-thick tantalum carbide coatings exceeding 200µm, defects such as cracks and pores are easily generated, resulting in a porous and loose coating that significantly reduces its performance advantages. Increasing the density of ultra-thick tantalum carbide coatings greatly increases the difficulty and complexity of their preparation process. Furthermore, the preparation of tantalum carbide coatings easily generates a large amount of carbon-containing waste, which is highly corrosive. Improper disposal may pollute the environment or harm human health; long-term storage conditions are extremely demanding; and recycling often incurs additional costs.

[0004] Therefore, it is necessary to provide a method for preparing tantalum-containing coatings to reduce the difficulty of preparing ultra-thick tantalum carbide coatings, reduce the defects of the prepared tantalum carbide coatings, and improve the density of the prepared tantalum carbide coatings; and to provide a method for recycling and reusing tantalum-containing waste generated in the preparation of tantalum-containing coatings to achieve safe, convenient, and low-cost recycling and reuse of tantalum-containing waste generated in the preparation of tantalum-containing coatings. Summary of the Invention

[0005] This specification provides one or more embodiments of a method for preparing a tantalum-containing coating. The method includes: using tantalum carbide as a raw material, forming a first tantalum carbide coating on the surface of a coating carrier via a first preparation method, wherein the first preparation method is physical vapor deposition (PVD); selecting a first tantalum source and a first carbon source, forming a second tantalum carbide coating on the surface of the first tantalum carbide coating via a second preparation method; and selecting a second tantalum source and a second carbon source, forming a third tantalum carbide coating on the surface of the second tantalum carbide coating via a third preparation method, wherein the third preparation method is chemical vapor deposition (CVD).

[0006] In some embodiments, the total thickness of the first tantalum carbide coating, the second tantalum carbide coating, and the third tantalum carbide coating is greater than 200 μm.

[0007] 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.

[0008] In some embodiments, the thickness of the first tantalum carbide coating is 0.05 μm to 1 μm, the thickness of the second tantalum carbide coating is 200 μm to 1000 μm, and the thickness of the third tantalum carbide coating is 20 μm to 80 μm.

[0009] In some embodiments, the second preparation method includes one or more of the following: sol-gel method, spraying method, electrophoretic deposition method, solid-phase reaction method, and self-propagating high-temperature synthesis method.

[0010] In some embodiments, the molar ratio of carbon to tantalum in the first tantalum source and the first carbon source is 1:(0.7-1.5).

[0011] In some embodiments, the growth rate of the third tantalum carbide coating is 5 μm / h to 20 μm / h.

[0012] In some embodiments, the first tantalum source includes at least one of tantalum oxide and tantalum pentaisopropoxy, the second tantalum source is tantalum chloride, and the first carbon source and the second carbon source are carbon-containing organic compounds.

[0013] In some embodiments, the coating carrier includes one or more of the following: a crucible for growing silicon carbide, a seed crystal holder, a lifting rod, a crystal growth furnace chamber, and a limiting member.

[0014] 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; and recycling the tantalum-containing waste.

[0015] In some embodiments, recycling tantalum-containing waste includes adding pure water to the tantalum-containing waste to obtain a mixture; adding an alkaline solution to the mixture to obtain a precipitate; filtering, washing, and drying the precipitate to obtain a target precipitate; grinding the target precipitate to obtain a powder; and introducing a first target gas into a high-temperature processing device to react the powder under high-temperature conditions for a certain time to obtain tantalum pentoxide powder.

[0016] In some embodiments, tantalum-containing waste includes tantalum pentachloride, tantalum carbide, tantalum pentoxide, elemental tantalum, and elemental carbon.

[0017] In some embodiments, the mixture includes the product of the reaction of tantalum pentachloride with pure water, tantalum carbide, tantalum pentoxide, elemental tantalum, and elemental carbon.

[0018] In some embodiments, the first target gas includes one or more of air, oxygen, and ozone, the high temperature condition is 600°C to 1100°C, and the time is 3h to 12h.

[0019] In some embodiments, grinding includes grinding the target precipitate after a certain amount has been reached, wherein the certain amount is determined based on the maximum capacity of the high-temperature processing equipment.

[0020] In some embodiments, the particle size of the powder is 100 mesh to 800 mesh.

[0021] In some embodiments, the purity of tantalum pentoxide powder is not less than 99.99%.

[0022] In some embodiments, the method further includes preparing tantalum carbide raw material based on tantalum pentoxide powder.

[0023] This specification provides one or more embodiments of an apparatus for growing silicon carbide. The surface of the apparatus is covered with a tantalum carbide coating prepared by the method of preparing a tantalum coating as described in the embodiments of this specification. The apparatus includes one or more of the following: a crucible, a seed crystal holder, a lifting rod, a crystal growth furnace chamber, and a limiting member.

[0024] This specification provides one or more embodiments of a tantalum carbide coating. The tantalum carbide coating is prepared using the method described in the embodiments of this specification for preparing tantalum-containing coatings.

[0025] This specification provides one or more embodiments of a method for recycling tantalum-containing waste generated during the preparation of tantalum-containing coatings. The method includes adding pure water to the tantalum-containing waste to obtain a mixture; adding an alkaline solution to the mixture to obtain a precipitate; filtering, washing, and drying the precipitate to obtain a target precipitate; grinding the target precipitate to obtain a powder; and introducing a first target gas into a high-temperature processing device to react the powder under high-temperature conditions for a certain time to obtain tantalum pentoxide powder.

[0026] In some embodiments, tantalum-containing waste includes tantalum pentachloride, tantalum carbide, tantalum pentoxide, elemental tantalum, and elemental carbon.

[0027] In some embodiments, the mixture includes the product of the reaction of tantalum pentachloride with pure water, tantalum carbide, tantalum pentoxide, elemental tantalum, and elemental carbon.

[0028] In some embodiments, the first target gas includes one or more of air, oxygen, and ozone, the high temperature condition is 600°C to 1100°C, and the time is 3h to 12h.

[0029] In some embodiments, grinding includes: grinding the target precipitate after a certain amount has been reached, wherein the certain amount is determined based on the maximum capacity of the high-temperature processing equipment.

[0030] In some embodiments, the particle size of the powder is 100 mesh to 800 mesh.

[0031] In some embodiments, the purity of tantalum pentoxide powder is not less than 99.99%.

[0032] In some embodiments, the method further includes preparing a tantalum carbide coating based on tantalum pentoxide powder.

[0033] In some embodiments, the preparation of tantalum carbide coating based on tantalum pentoxide powder includes mixing tantalum pentoxide powder with a carbonaceous reducing agent to obtain a mixture to be treated; introducing a second target gas into a high-temperature treatment device and reacting the mixture to be treated at a certain temperature for a certain time to obtain tantalum carbide powder, wherein the second target gas includes one or more of hydrogen and inert gases; and preparing tantalum carbide coating by physical vapor deposition using tantalum carbide powder as raw material.

[0034] In some embodiments, the preparation of tantalum carbide coating based on tantalum pentoxide powder includes preparing tantalum carbide coating by means of tantalum pentoxide powder and carbon source as raw materials, and the target means includes one or more of the following: sol-gel method, spraying method, electrophoretic deposition method, solid-state reaction method, and self-propagating high-temperature synthesis method.

[0035] In some embodiments, the preparation of tantalum carbide coating based on tantalum pentoxide powder includes reacting tantalum pentoxide powder with chlorine gas to generate tantalum pentachloride; and preparing tantalum carbide coating by chemical vapor deposition using tantalum pentachloride and a carbon source as raw materials.

[0036] This specification provides one or more embodiments of an apparatus for growing silicon carbide. The surface of the apparatus is covered with a tantalum carbide coating prepared by a method for recycling tantalum-containing waste generated during the preparation of tantalum-containing coatings as described in the embodiments of this specification. The apparatus includes one or more of the following: a crucible, a seed crystal holder, a lifting rod, a crystal growth furnace chamber, and a limiting component. Attached Figure Description

[0037] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein:

[0038] Figure 1 is a flowchart of an exemplary method for preparing a tantalum-containing coating according to some embodiments of this specification;

[0039] Figure 2 is a schematic diagram of an exemplary tantalum-coated structure according to some embodiments of this specification;

[0040] Figure 3 is a schematic diagram of an exemplary apparatus for growing silicon carbide according to some embodiments of this specification;

[0041] Figure 4 is a flowchart of an exemplary method for preparing a tantalum-containing coating according to other embodiments of this specification;

[0042] Figure 5A is an X-ray diffraction (XRD) pattern of tantalum pentoxide powder according to some embodiments of this specification;

[0043] Figure 5B is the element list corresponding to Figure 5A;

[0044] Figure 5C is the pattern list corresponding to Figure 5A;

[0045] Figure 6 is a flowchart of an exemplary method for recycling tantalum-containing waste generated during the preparation of tantalum-containing coatings according to some embodiments of this specification. Detailed Implementation

[0046] To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0047] It should be understood that the terms “system,” “device,” “unit,” and / or “module” used herein are one way to distinguish different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0048] As indicated in this specification and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0049] Flowcharts are used in this specification to illustrate the operations performed by the system according to embodiments of this specification. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, the steps can be processed in reverse order or simultaneously. Furthermore, other operations can be added to these processes, or one or more steps can be removed from them.

[0050] Figure 1 is a flowchart of an exemplary method for preparing a tantalum-containing coating according to some embodiments of this specification. As shown in Figure 1, process 100 includes the following steps.

[0051] Step 110: Using tantalum carbide as raw material, a first tantalum carbide coating is generated on the surface of the coating carrier through a first preparation method.

[0052] Tantalum carbide (TaC) possesses high melting point (3880℃, one of the highest melting points among known compounds), high hardness (Mohs hardness 9, close to diamond), excellent thermal and chemical stability (stable in strong acid, strong alkali, and strong oxidizing environments), and good electrical and thermal conductivity due to its strong chemical bonding 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 form a first tantalum carbide coating on the surface of a coating carrier through a first preparation method. Compared to bulk solids, tantalum carbide powder has a larger specific surface area, which is beneficial for vaporization and deposition, resulting in a more uniform coating, increased process stability, and improved coating density.

[0053] The first preparation method refers to a method capable of preparing a first tantalum carbide coating. In some embodiments, the first preparation method is physical vapor deposition (PVD). Physical vapor deposition refers to a method that uses physical methods to vaporize a material source (solid or liquid) into gaseous molecules and deposit them on the surface of a substrate to form a coating. For example, tantalum carbide raw material can be vaporized into molecules by evaporation, sublimation, or sputtering, and deposited on the substrate surface to form a tantalum carbide coating. Commonly used physical vapor deposition methods include vacuum evaporation, magnetron sputtering, and arc ion plating / deposition. In some embodiments, tantalum carbide powder ground to a certain particle size can be heated to the sublimation temperature, causing the tantalum carbide to transform from a solid phase to a gaseous phase. The gaseous tantalum carbide is then 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 requirements of the first preparation method.

[0054] The physical vapor deposition method has a simple preparation process, and the resulting tantalum carbide coating has few impurities and voids, high density, and strong adhesion to the coating carrier. This ensures that the first tantalum carbide coating is firmly bonded to the surface of the coating carrier, reducing the risk of tantalum carbide coating peeling off during use.

[0055] Figure 2 is a schematic diagram of an exemplary tantalum-coated structure according to some embodiments of this specification. The coating carrier refers to the object to which the coating is applied. For example, the coating carrier 210 in Figure 2. By applying a coating, the function or performance of the coating carrier can be increased. For example, a coating carrier coated with tantalum carbide will have improved high-temperature resistance, corrosion resistance, oxidation resistance, wear resistance, thermal conductivity, and impact resistance. The coating carrier can be a metal, non-metal, or other material.

[0056] In some embodiments, the coating carrier includes equipment or components for growing silicon carbide. For example, FIG3 is a schematic diagram of an exemplary equipment for growing silicon carbide according to some embodiments of this specification. As shown in FIG3, the equipment for growing silicon carbide may include a crucible 310, a seed crystal holder 320, a lifting rod 330, a furnace chamber 340, etc. The crucible 310 is a component for placing the melt required for silicon carbide crystal growth. When the melt in the crucible 310 is in full contact with the silicon carbide seed crystal, the melt can be adsorbed onto 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 side of the seed crystal holder 320 in contact with the melt may be provided with a seed crystal bonding surface, on which the silicon carbide seed crystal can be bonded and contact the melt in the crucible to form a silicon carbide crystal. The lifting rod 330 is a component for providing support and motion control. The lifting rod 330 is typically located above the crucible containing the molten material, and its lower end is connected to the seed crystal holder 320. By controlling the rotation and lifting motion of the lifting rod, silicon carbide crystal growth is achieved. The furnace chamber 340 is a component that provides the space for silicon carbide crystal growth, and it can accommodate multiple components required for crystal growth (such as the crucible 310, seed crystal holder 320, and lifting rod 330).

[0057] Equipment used for growing silicon carbide may also include limiting elements (not shown in Figure 3). Limiting elements are devices used to restrict 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, safe operation of the equipment is ensured.

[0058] In some embodiments, the coating carrier includes one or more of the following: a crucible, a seed crystal holder, a lifting rod, a crystal growth furnace chamber, and a limiting component used for growing silicon carbide. As a key material in the semiconductor field, silicon carbide has a melting point as high as 2700°C, which places extremely high demands on its crystal growth equipment and results in significant wear and tear. By coating the surfaces of crucibles, seed crystal holders, lifting rods, crystal growth furnace chambers, and limiting components used for silicon carbide growth with a tantalum carbide coating, the high-temperature resistance, chemical stability, wear resistance, and corrosion resistance of these components can be increased, effectively extending their service life and reducing wear and tear costs.

[0059] The first tantalum carbide coating refers to the first layer of tantalum carbide coating on the surface of the coating carrier. For example, the first tantalum carbide coating 220 in Figure 2. The first tantalum carbide coating generated by the first preparation method is equivalent to a dense guiding layer. It has a strong bonding force with the coating carrier and can also guide the subsequent crystallization of the second tantalum carbide coating, improve the density and flatness of the crystallization of the second tantalum carbide coating, as well as the bonding force with the first tantalum carbide coating, reduce the risk of tantalum carbide coating peeling off during use, and reduce the difficulty of sealing the pores of the second tantalum carbide coating by the third preparation method.

[0060] 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 using a second preparation method.

[0061] The second preparation method refers to a method capable of preparing a second tantalum carbide coating. In some embodiments, the second preparation method may include one or more of the following: sol-gel method, spraying method, electrophoretic deposition method, solid-state reaction method, and self-propagating high-temperature synthesis method.

[0062] The sol-gel method refers to a method in which a metal organic or inorganic compound is solidified through a solution, sol, and gel process, and then subjected to heat treatment 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 through a chemical pathway, which is then converted into a solid through a sol-gel process, and finally carbonized by high-temperature sintering to obtain a second tantalum carbide coating.

[0063] Spraying refers to a method of forming a coating by spraying a liquid compound onto a substrate surface using a high-speed airflow. For example, a spraying liquid is prepared by mixing a first carbon source, a first tantalum source, and an organic solvent, and a second tantalum carbide coating is formed on the surface of a first tantalum carbide coating by spraying or brushing.

[0064] Electrophoretic deposition is a method that uses an external electric field to deposit charged nanoparticles or ions from a dispersion onto a substrate to form a coating. For example, a suspension is prepared by mixing a first carbon source, a first tantalum source, and an organic solvent. The suspension is placed in an electrophoretic deposition apparatus, and an external electric field causes charged carbon ions and tantalum ions to move toward the electrode and react to deposit on the surface of a first tantalum carbide coating to form a second tantalum carbide coating.

[0065] Solid-state reaction refers to the process in which a chemical reaction occurs between solids to generate a new solid product. For example, a first solid carbon source and a first solid tantalum source (such as carbon powder and tantalum pentoxide powder) are uniformly coated on the surface of a first tantalum carbide coating and sintered to form a second tantalum carbide coating through a solid-state reaction.

[0066] Self-propagating high-temperature synthesis refers to a method in which materials with sufficiently high heat of generation transform reactants into products through the self-propagation of combustion waves after ignition. For example, a first carbon source and a first tantalum source are thoroughly mixed and pressed into shape (i.e., material) on the surface of a first tantalum carbide coating. The material is ignited by an external heat source, initiating a chemical reaction. The heat of generation causes the temperature of adjacent materials to rise rapidly and continues to initiate new chemical reactions until all materials have completely reacted to form a second tantalum carbide coating.

[0067] Compared to the first and third preparation methods, the second preparation method, which uses one or more of the following: sol-gel method, spraying method, electrophoretic deposition method, solid-state reaction method, and self-propagating high-temperature synthesis method, can rapidly, cost-effectively, and with high conversion rates produce a thicker second tantalum carbide coating. Understandably, while the second preparation method can efficiently produce a thicker second tantalum carbide coating, it generally results in a porous and less dense structure. This application uses a first tantalum carbide coating prepared by the first preparation method to guide the second tantalum carbide coating, and a third tantalum carbide coating prepared by the third preparation method to seal the voids in the second tantalum carbide coating. This reduces defects such as pores and cracks in the second tantalum carbide coating, improves its density, and thus produces an ultra-thick and dense tantalum carbide coating.

[0068] Traditional methods for obtaining ultra-thick (total thickness greater than 200 μm) and dense tantalum carbide coatings, using sol-gel methods, spraying, electrophoretic deposition, solid-state reaction, or self-propagating high-temperature synthesis, place extremely high demands on the formulation of deposition raw materials, deposition processes, and coating heat treatment, making coating preparation extremely difficult. In contrast, the method proposed in this application significantly reduces the process requirements for preparing ultra-thick (total thickness greater than 200 μm) and dense tantalum carbide coatings, lowers the preparation difficulty, and is more feasible.

[0069] Understandably, tantalum carbide is a carbide of tantalum, and its formation requires a tantalum source providing tantalum and a carbon source providing carbon. The first tantalum source refers to the tantalum-containing raw material used to form the second tantalum carbide coating. The first carbon source refers to the carbon-containing raw material used to form the second tantalum carbide coating. In some embodiments, the first tantalum source may include at least one of tantalum oxide and tantalum isopropoxy. For example, the first tantalum source may be tantalum pentoxide, tantalum pentaisopropoxy, etc. In some embodiments, the first carbon source may be a carbon-containing organic compound. For example, the first carbon source may be polyvinyl alcohol, graphite, hydrocarbon compounds, etc.

[0070] 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 as closely as possible to the second preparation method. For example, when the second preparation method is a sol-gel method, the first tantalum source can be tantalum isopropoxy, and the first carbon source can be polyvinyl alcohol. As another example, when the second preparation method is a solid-state reaction method, the first tantalum source can be tantalum oxide, and the first carbon source can be carbon black, etc.

[0071] By selecting at least one of tantalum oxide and tantalum isopropoxy as the first tantalum source and a carbon-containing organic compound as the first carbon source, it can be adapted to the second preparation method to obtain a second tantalum carbide coating.

[0072] In some embodiments, the molar ratio of carbon to tantalum in the first tantalum source and the first carbon source is 1:(0.7-1.5). Preferably, the molar ratio of carbon to tantalum in the first tantalum source and the first carbon source can also be 1:1. It is understood that the carbon-tantalum ratio in the tantalum carbide molecular formula is 1:1, and when preparing the tantalum carbide coating, the molar ratio of carbon to tantalum in the first tantalum source and the first carbon source should also be approximately 1:1 for optimal results. If the proportion of tantalum is too high, the first tantalum source will not react completely, and the carbon in the first tantalum carbide coating will also react during the preparation process, resulting in the loss of the first tantalum carbide coating. If the proportion of carbon is too high, the first carbon source will not react completely, and excessive carbon embedding in the generated second tantalum carbide coating will cause defects, resulting in a porous second tantalum carbide coating, increasing the internal stress of the second tantalum carbide coating, and making it prone to cracking under 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 proportions of carbon and tantalum can be made approximately the same, ensuring complete reaction of the first tantalum source and the first carbon source, resulting in a high-quality second tantalum carbide coating. Furthermore, in the formulations of the embodiments in this specification, only the molar ratio of carbon to tantalum needs to meet the requirements; the concentration is not critical, thus reducing the complexity of the raw material formulation process.

[0073] In some embodiments, a certain mass of a first carbon source, a first tantalum source, and an organic solvent (such as ethanol) can be mixed to prepare a spraying liquid. At a certain temperature, the spraying liquid is uniformly sprayed onto the surface of the first tantalum carbide coating away from the coating carrier using a spraying device. The coating is then placed in a high-temperature treatment device (i.e., a device capable of treating materials under high-temperature conditions, such as a vacuum furnace or muffle furnace), and an inert gas is introduced into the high-temperature treatment device to sinter and obtain a second tantalum carbide coating. The specific mass and temperature can be set based on experience or the requirements of the second preparation method.

[0074] The second tantalum carbide coating refers to the second layer of tantalum carbide coating on the surface of the coating carrier. For example, the second tantalum carbide coating 230 in Figure 2. The second tantalum carbide coating generated by the second preparation method is thicker than the other layers, but the structural defects are relatively larger, requiring the assistance of other layers to improve it.

[0075] 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 through a third preparation method.

[0076] The second tantalum source refers to the tantalum-containing raw material used to generate the third tantalum carbide coating. The second carbon source refers to the carbon-containing raw material used to generate the third tantalum carbide coating. In some embodiments, the second tantalum source can be tantalum chloride. For example, the second tantalum source can be tantalum pentachloride. In some embodiments, the second carbon source can be a carbon-containing organic compound. For example, the second carbon source can be polyvinyl alcohol, graphite, hydrocarbon compounds, etc. By selecting tantalum pentachloride as the second tantalum source and a carbon-containing organic compound as the second carbon source, it can be adapted to the third preparation method to obtain the third tantalum carbide coating.

[0077] The third preparation method refers to a method capable of preparing a third tantalum carbide coating. In some embodiments, the third preparation method is chemical vapor deposition (CVD). Chemical vapor deposition refers to a method that uses one or more gaseous compounds or elements containing the elements required for the coating to chemically react on a substrate surface and deposit to form a coating. For example, chemical vapor deposition can be achieved by chemically reacting a second tantalum source gas and a second carbon source gas at high temperature and then depositing the mixture.

[0078] In some embodiments, an inert gas can be introduced into a high-temperature processing apparatus, and a coating carrier with a first tantalum carbide coating and a second tantalum carbide coating can be placed inside. The second carbon source and the second tantalum source are then vaporized and reacted with an auxiliary gas (such as hydrogen, nitrogen, etc.) in the high-temperature processing apparatus to deposit a third tantalum carbide coating on the surface of the second tantalum carbide coating at a certain growth rate. The growth rate refers to a parameter representing the thickness increase of the tantalum carbide coating per unit time. A certain growth rate can be set based on experience or the requirements of the third preparation method.

[0079] A third tantalum carbide coating, prepared by chemical vapor deposition (CVD), is deposited and grown on the surface of a second tantalum carbide coating. During deposition, it seals the pores of the second tantalum carbide coating, making it denser. Furthermore, CVD is a simple process, and the resulting third tantalum carbide coating has few impurities and voids, high density, and strong adhesion to the second tantalum carbide coating. This allows the third tantalum carbide coating to seal the voids of the second tantalum carbide coating while also bonding firmly to it.

[0080] In some embodiments, the growth rate of the third tantalum carbide coating can be 5 μm / h to 20 μm / h. It is understood that if the growth rate of the third tantalum carbide coating is too slow (e.g., below 5 μm / h), the third tantalum carbide coating may only penetrate the pores of the second tantalum carbide coating during deposition, but cannot seal the pores; if the growth rate of the third tantalum carbide coating is too fast (e.g., above 20 μm / h), the sealing depth of the pores in the second tantalum carbide coating during deposition may be insufficient. By setting the growth rate of the third tantalum carbide coating to 5 μm / h to 20 μm / h, the sealing effect on the pores of the second tantalum carbide coating during deposition can be better, thereby improving the structural defects of the second tantalum carbide coating.

[0081] The third tantalum carbide coating refers to the third layer of tantalum carbide coating on the surface of the coating carrier. For example, the third tantalum carbide coating 240 in Figure 2. The third tantalum carbide coating generated by the third preparation method is deposited and grown on the surface of the second tantalum carbide coating. During deposition, it can block the pores on the surface of the second tantalum carbide coating, making the second tantalum carbide coating more dense.

[0082] In some embodiments, the total thickness of the first, second, and third tantalum carbide coatings is greater than 200 μm. It is understood that the purpose of preparing the tantalum carbide coating is to protect the coating carrier. Under the same conditions, the thicker the tantalum carbide coating, the higher the number of chemical reactions it can withstand, such as oxidation and pyrolysis. By preparing a tantalum carbide coating with a total thickness greater than 200 μm, the number of chemical reactions the tantalum carbide coating can withstand can be increased, effectively reducing adverse effects such as cracking caused by wear, extending service life, and enhancing the protective effect. In some embodiments, the thickness of the first, second, and third tantalum carbide coatings can be from 200 μm to 1000 μm. While maintaining a relatively large thickness, excessive thickness is avoided to prevent a decrease in the adhesion between the tantalum carbide coating and the coating carrier, which could lead to peeling and cracking of the coating.

[0083] In some embodiments, the thickness of the second tantalum carbide coating can 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 can be greater than the sum of the thicknesses of the first and third tantalum carbide coatings. It is understood that preparing ultra-thick tantalum carbide coatings (thickness greater than 200 μm) using the first and third preparation methods requires high process conditions and costs, and the growth rate is slow, making it difficult to achieve the required thickness. The second preparation method, however, can efficiently and cost-effectively prepare ultra-thick tantalum carbide coatings (thickness greater than 200 μm). Therefore, the thickness of the second tantalum carbide coating is set to be the thickest, greater than the thickness of the first tantalum carbide coating, the thickness of the third tantalum carbide coating, and their sum.

[0084] In some embodiments, the thickness of the first tantalum carbide coating is 0.05 μm to 1 μm. If the thickness of the first tantalum carbide coating is too low (e.g., below 0.05 μm), it is difficult to guide the second tantalum carbide coating; if the thickness of the first tantalum carbide coating is too high (e.g., above 1 μm), the growth process of the first tantalum carbide coating is slow and time-consuming due to the growth rate of the first preparation method. Preferably, the thickness of the first tantalum carbide coating can be 0.05 μm to 0.3 μm.

[0085] In some embodiments, the thickness of the second tantalum carbide coating is 200µm to 1000µm. Since the thickness is mainly provided by the second tantalum carbide coating, if the thickness of the second tantalum carbide coating is too low (e.g., below 200µm), the total thickness may not meet the standard (not reaching the ultra-thickness), affecting the overall quality of the tantalum carbide coating; if the thickness of the second tantalum carbide coating is too high (e.g., above 1000µm), the adhesion of the second tantalum carbide coating is reduced, resulting in unnecessary process waste.

[0086] In some embodiments, the thickness of the third tantalum carbide coating is 20 μm to 80 μm. The thickness of the third tantalum carbide coating depends on the aforementioned growth rate and the required sealing time, in order to achieve the best sealing effect on the second tantalum carbide coating.

[0087] In some embodiments of this specification, by setting the thickness of the first tantalum carbide coating to 0.05µm to 1µm, the thickness of the second tantalum carbide coating to 200µm to 1000µm, and the thickness of the third tantalum carbide coating to 20µm to 80µm, 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 sealing effect of the third tantalum carbide coating) can be achieved, thereby generating a dense and relatively thick tantalum carbide coating.

[0088] In some embodiments of this specification, a first tantalum carbide coating is formed on the surface of a coating carrier using tantalum carbide as a raw material through a first preparation method (physical vapor deposition); a second tantalum carbide coating is formed on the surface of the first tantalum carbide coating using a second preparation method (sol-gel method, spraying method, electrophoretic deposition method, solid-state reaction method, and / or self-propagating high-temperature synthesis method) by selecting a first tantalum source and a first carbon source; and a third tantalum carbide coating is formed on the surface of the second tantalum carbide coating using a third preparation method (chemical vapor deposition method) by selecting a second tantalum source and a second carbon source. This method combines the advantages of physical vapor deposition, traditional coating preparation methods (sol-gel method, spraying method, electrophoretic deposition method, solid-state reaction method, or self-propagating high-temperature synthesis method) and chemical vapor deposition to prepare an ultra-thick (total thickness greater than 200 μm) and dense tantalum carbide coating with a PVD guiding layer + ultra-thick intermediate layer + CVD sealing layer structure.

[0089] Traditional methods for obtaining ultra-thick (total thickness greater than 200 μm) and dense tantalum carbide coatings using sol-gel methods, spraying methods, electrophoretic deposition methods, solid-state reaction methods, or self-propagating high-temperature synthesis methods place extremely high demands on the formulation of deposition raw materials, deposition processes, and coating heat treatment processes, making coating preparation extremely difficult. In contrast, the solution proposed in this application guides the second tantalum carbide coating with a first tantalum carbide coating obtained by a first preparation method, and then seals the voids in the second tantalum carbide coating with a third tantalum carbide coating obtained by a third preparation method. This reduces defects such as pores and cracks in the second tantalum carbide coating, improves its density, and thus prepares an ultra-thick (total thickness greater than 200 μm) and dense tantalum carbide coating. This significantly reduces the process requirements for preparing ultra-thick and dense tantalum carbide coatings, lowers the preparation difficulty, and is more feasible.

[0090] An exemplary method 1 for preparing a tantalum-containing coating may include the following steps (S11 corresponds to step 110 above, S12 to S15 correspond to step 120 above, and S16 corresponds to step 130 above):

[0091] S11. Use grinding equipment (such as a ball mill) to obtain fully ground and dried tantalum carbide powder (particle size set according to requirements or experience), and deposit the tantalum carbide powder on the surface of a graphite disk (i.e., coating carrier) using 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.

[0092] S12. Disperse pentaisopropoxytantalum (i.e., the first tantalum source) and polyvinyl alcohol (i.e., the first carbon source) in isopropanol (i.e., organic solvent), add nitric acid and ammonia water to mix, and prepare a sol containing the first carbon source and the first tantalum source, wherein the molar ratio of tantalum element in pentaisopropoxytantalum to carbon element in polyvinyl alcohol is 1:1.

[0093] S13. The sol is coated onto the surface of the first tantalum carbide coating with a single spin coating thickness using a spin coating method. After drying in a drying device (such as an oven), the coating and drying are repeated a certain number of times to obtain the second tantalum carbide coating to be treated. The drying device temperature is 80℃~150℃, the drying time is 1h~5h, the certain number of times is 6 to 10 times, and the single spin coating thickness is 34um~60um. It is understandable that if the single spin coating thickness is too thin (such as less than 34um), it is necessary to repeat the process many times to achieve the thickness requirement of the second tantalum carbide coating, which increases the complexity of the process. If the single spin coating thickness is too thick (such as more than 60um), the process stability is low and it is easy to lead to an increase in defects.

[0094] S14. Inert gas is introduced into a high-temperature treatment device, and a graphite disk with the second tantalum carbide coating to be treated is placed into the high-temperature treatment device (such as a vacuum furnace). The first sintering is carried out at a first sintering temperature to obtain a pretreated second tantalum carbide coating. The first sintering temperature is 300℃~600℃, the heating rate to reach the first sintering temperature is 0.5℃ / min~5℃ / min, the sintering time of the first sintering is 1h~6h, and the cooling rate after the first sintering is 20℃ / min~100℃ / min.

[0095] S15. The graphite disk with the pretreated second tantalum carbide coating is placed in a high-temperature treatment device and subjected to a second sintering at a second sintering temperature to obtain a second tantalum carbide coating with a thickness of 204um-600um. The second sintering temperature is higher than the first sintering temperature, ranging from 1000℃ to 1500℃. The heating rate to achieve the second sintering temperature is 1℃ / min to 10℃ / min. The sintering time for the second sintering is 3h to 5h. The cooling rate after the second sintering is 20℃ / min to 100℃ / min. It can be understood that the first sintering is to make the sol of the second tantalum carbide coating more tightly bonded to the first tantalum carbide coating, and the second sintering is to enable the second tantalum carbide coating to undergo a phase transformation.

[0096] S16. 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 5 μm / h to 20 μm / h to obtain a third tantalum carbide coating with a thickness of 20-80 μm.

[0097] An exemplary method 2 for preparing a tantalum-containing coating may include the following steps (S21 corresponds to step 110 above, S22 to S24 correspond to step 120 above, and S25 corresponds to step 130 above):

[0098] S21. Use grinding equipment (such as a ball mill) to obtain fully ground and dried tantalum carbide powder (particle size set according to requirements or experience), and deposit the tantalum carbide powder on the surface of a graphite disk (i.e., coating carrier) using 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.

[0099] S22. Tantalum pentoxide (i.e., the second tantalum source), tantalum pentaisopropoxy (i.e., the second tantalum source), and polyvinyl alcohol (i.e., the second carbon source) are dispersed in ethanol to obtain a spraying liquid. The molar ratio of tantalum element in tantalum pentoxide and tantalum pentaisopropoxy to 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 is understood that tantalum pentoxide has good melt fluidity and acts as a solvent at high temperatures, increasing the fluidity of the formulation system and making the prepared tantalum carbide coating more dense.

[0100] S23. The graphite disk with the first tantalum carbide coating is placed on a heating device (such as a constant temperature heating plate) and heated. The spraying liquid prepared in S2 is uniformly sprayed onto the surface of the first tantalum carbide coating using a spraying device (such as an ultrasonic nozzle) to obtain the second tantalum carbide coating to be treated. The heating temperature of the heating device is 80℃-120℃, the single layer spraying thickness is 5um, and the total spraying thickness is 200um.

[0101] S24. Inert gas is introduced into a high-temperature treatment device (such as a vacuum furnace), and a graphite disk with the second tantalum carbide coating to be treated is placed into the high-temperature treatment device to sinter and obtain a second tantalum carbide coating with a thickness of 200 μm. The sintering temperature is 1300℃~2100℃, the heating rate to reach the sintering temperature is 1℃ / min~10℃ / min, the sintering time is 3h~8h, and the cooling rate after sintering is about 20℃ / min-100℃ / min.

[0102] S25. 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 5 μm / h to 20 μm / h to obtain a third tantalum carbide coating with a thickness of 20-80 μm. Based on this, S22-S25 can be repeated to achieve thickness stacking (the thickness of the second tantalum carbide coating and the third tantalum carbide coating are stacked) until the desired total thickness of the tantalum carbide coating is achieved.

[0103] In some embodiments, the method for preparing a tantalum-containing coating may further include 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; and recycling the tantalum-containing waste. For more details on achieving recycling, please refer to Figure 4 and its related description.

[0104] Figure 4 is an exemplary flowchart of a method for preparing a tantalum-containing coating according to other embodiments of this specification. As shown in Figure 4, process 400 includes the following steps.

[0105] Step 410: Using tantalum carbide as raw material, a first tantalum carbide coating is generated on the surface of the coating carrier through the first preparation method.

[0106] Step 420: Select the first tantalum source and the first carbon source, and generate the second tantalum carbide coating on the surface of the first tantalum carbide coating through the second preparation method.

[0107] 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 through a third preparation method.

[0108] For more details on steps 410-430, please refer to the relevant descriptions of steps 110-130 in Figure 1, which will not be repeated here.

[0109] Step 440: Recover tantalum-containing waste generated during the preparation of the first tantalum carbide coating, the second tantalum carbide coating, and the third tantalum carbide coating.

[0110] Tantalum-containing waste refers to waste containing tantalum element generated during the preparation of tantalum carbide coatings. More information on tantalum-containing waste can be found in the following description. In some embodiments, the waste materials remaining after the formation of the tantalum carbide coating can be directly collected, achieving the recycling of tantalum-containing waste.

[0111] Step 450: Recycle and reuse tantalum-containing waste.

[0112] 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 realizing the recycling and reuse of tantalum-containing waste.

[0113] In some embodiments of this specification, tantalum-containing waste generated during the preparation of the first, second, and third tantalum carbide coatings is recycled; tantalum carbide raw materials are prepared based on the tantalum-containing waste, realizing the recycling of tantalum elements during the preparation of tantalum-containing coatings. This method can safely, conveniently, and at low cost treat tantalum-containing waste, solve the problem of storing and treating toxic tantalum-containing waste, and simultaneously achieve the recycling of tantalum elements.

[0114] In some embodiments, recycling tantalum-containing waste may include the following steps S1-S5.

[0115] S1. Add pure water to tantalum-containing waste to obtain a mixture.

[0116] In some embodiments, tantalum-containing waste may include tantalum pentachloride, tantalum carbide, tantalum pentoxide, elemental tantalum, and elemental carbon. This tantalum-containing waste may originate from the tantalum source used in the preparation of the first, second, and third tantalum carbide coatings, byproducts generated, or impurities in the raw materials. For example, tantalum pentachloride may originate from the second tantalum source. Tantalum carbide, tantalum pentoxide, elemental tantalum, and elemental carbon may originate from byproducts generated during the preparation of the third tantalum carbide coating by chemical vapor deposition, or impurities contained in the raw materials. The tantalum chloride, tantalum carbide, and elemental tantalum in the tantalum-containing waste can be converted to tantalum pentoxide through subsequent chemical reactions, while the elemental carbon is converted to carbon dioxide gas at high temperatures, without other impurities, thus yielding high-purity tantalum pentoxide. Further details regarding the purity of tantalum pentoxide can be found in the following description.

[0117] Understandably, tantalum pentachloride is a strongly acidic chloride with unstable chemical properties. It decomposes in moist air or water to produce hydrogen chloride, and can also decompose or react with other substances (alcohols, amines, strong alkalis, etc.) under light or high temperatures. It is highly corrosive and can cause serious harm to the eyes, skin, and mucous membranes, classifying it as a Class II hazardous chemical. Therefore, tantalum-containing waste must be stored in sealed, water-proof, light-proof, and alkali-proof containers, which is difficult and costly. Through recycling, tantalum-containing waste can be converted into high-purity and harmless tantalum pentoxide, which can then be used as a raw material for preparing tantalum carbide coatings, achieving circular utilization.

[0118] In some embodiments, tantalum-containing waste may be in powder form to increase the specific surface area of ​​the material, thereby increasing the contact area of ​​the reactants in subsequent reactions and allowing the reaction to proceed fully.

[0119] In some embodiments, tantalum-containing waste can be added to pure water in small amounts, multiple times, and slowly (to allow the reaction to proceed fully). After stirring evenly, it can be allowed to stand for a certain period of time to allow the substances in the tantalum-containing waste that can react with water to react fully with the water, thus obtaining a mixture. In some embodiments, the certain period of time can be 0.5 h to 3 h. It is understood that the reaction between tantalum pentachloride in the tantalum-containing waste and pure water requires time. By allowing it to stand for 0.5 h to 3 h, the reaction can be made complete, increasing the yield and improving the purity of the final product.

[0120] Understandably, some substances in tantalum-containing waste can react with water to generate new products, while others cannot. Therefore, the resulting mixture may include substances in the tantalum-containing waste that cannot react with water, new products generated from substances in the tantalum-containing waste that can react with water, and liquids (solutions composed of water and other soluble substances, etc.).

[0121] When tantalum-containing waste includes tantalum pentachloride, tantalum carbide, tantalum pentoxide, elemental tantalum, and elemental carbon, only tantalum pentachloride can react with pure water under normal temperature and pressure to produce tantalum hydroxide and hydrogen chloride; the remaining substances cannot react with water. The resulting mixture can include the products of the reaction between tantalum pentachloride and pure water (i.e., tantalum hydroxide and hydrogen chloride), tantalum carbide, tantalum pentoxide, elemental tantalum, and elemental carbon.

[0122] In some embodiments, the mixture may be acidic. Understandably, when tantalum pentachloride in tantalum-containing waste reacts with pure water, it produces hydrogen chloride (i.e., hydrochloric acid), making the mixture acidic overall.

[0123] As mentioned earlier, tantalum pentachloride is an unstable and easily decomposed hazardous chemical, making the storage of tantalum-containing waste difficult and costly. By adding pure water to tantalum-containing waste, tantalum pentachloride can be fully reacted. Among the products generated, tantalum hydroxide is stable and not easily decomposed, and hydrochloric acid can be used for subsequent neutralization. Ultimately, the tantalum pentachloride in tantalum-containing waste is rendered harmless, thereby reducing storage difficulty and cost.

[0124] S2. Add an alkaline solution to the mixture to obtain a precipitate.

[0125] In some embodiments, an alkaline solution may be slowly added dropwise to the mixture while stirring until the mixture becomes neutral (pH 7), thus obtaining a precipitate.

[0126] In some embodiments, the alkaline solution may include sodium hydroxide solution, potassium hydroxide solution, ammonia water, etc. It is understood that tantalum hydroxide, the product of the reaction between tantalum pentachloride and pure water in tantalum-containing waste, is an alkaline precipitate. However, the presence of another product, hydrogen chloride, creates an acidic environment in the mixture, which inhibits the precipitation of tantalum hydroxide. Adding an alkaline solution can adjust the acidity or alkalinity of the mixture, transforming it into a neutral environment and improving the precipitation effect of tantalum hydroxide.

[0127] Precipitates are insoluble solid substances that precipitate from a solution. In some embodiments, precipitates may include tantalum hydroxide, tantalum carbide, tantalum pentoxide, elemental tantalum, or elemental carbon.

[0128] S3. Filter, wash and dry the precipitate to obtain the target precipitate.

[0129] In some embodiments, a filtration device (such as a vacuum filter, membrane filter, etc.) can be used to filter the precipitate in the mixture, wash it with water, and then dry it to obtain the target precipitate. It is understood that by filtering and washing the precipitate, the precipitate in the mixture can be separated from the mother liquor, and soluble impurities adsorbed by the precipitate and residual mother liquor (i.e., liquid in the mixture) in the precipitate can be removed, thereby obtaining a relatively pure target precipitate. In some embodiments, the filtration and washing steps can be repeated 2 to 7 times to make the washing more thorough and the precipitate purer.

[0130] In some embodiments, the drying temperature can be 80°C to 120°C.

[0131] S4. Grind the target precipitate to obtain powder.

[0132] In some embodiments, the target precipitate can be ground using a grinding device (such as an ultrafine grinder) to obtain a powder. It is understood that grinding increases the specific surface area of ​​the target precipitate, thereby increasing its contact area with oxygen in the subsequent oxidation reaction and ensuring a more complete oxidation process.

[0133] In some embodiments, the target precipitate may be ground after a certain amount has been reached. In some embodiments, the certain amount may be determined based on the maximum capacity of the high-temperature treatment equipment for the subsequent redox reaction. For example, the certain amount may be equivalent to the maximum capacity of the high-temperature treatment equipment.

[0134] Understandably, the target reactant needs to be put into high-temperature treatment equipment for oxidation reaction. By determining a certain amount based on the maximum capacity of the high-temperature treatment equipment, and grinding the target precipitate after a certain amount has been reached, the capacity utilization rate of the high-temperature treatment equipment can be maximized, avoiding the waste of additional production resources (such as power resources, labor resources, etc.).

[0135] In some embodiments, the particle size of the powder can be 100 mesh to 800 mesh. The particle size can also be 200 mesh to 700 mesh. The particle size can also be 300 mesh to 500 mesh. It is understood that if the particle size of the powder is too coarse (e.g., less than 100 mesh), the contact area with oxygen during subsequent oxidation reactions will be too small, resulting in incomplete oxidation and affecting the yield and purity of the product. If the particle size of the powder is too fine (e.g., greater than 800 mesh), it constitutes over-processing, easily causing unnecessary waste of production resources and slowing down the grinding process. By setting the particle size of the powder to 100 mesh to 800 mesh, the powder can fully react in subsequent oxidation reactions, obtaining high-quality oxidation products while avoiding unnecessary waste of production resources.

[0136] S5. In a high-temperature processing device, the first target gas is introduced, and the powder is reacted under high-temperature conditions for a certain time to obtain tantalum pentoxide powder.

[0137] The first target gas refers to a gas capable of participating in the oxidation reaction. For example, the first target gas can be a gas containing oxygen. In some embodiments, the first target gas may include one or more of air, oxygen, and ozone. By setting the first target gas to the above-mentioned gases, sufficient oxygen content can be provided to ensure the smooth progress of the oxidation reaction.

[0138] In some embodiments, the high-temperature condition (i.e., the reaction temperature) can be 600℃ to 1100℃, and the certain time (i.e., the reaction time) can be 3h to 12h. It is understood that powders exhibit relatively stable chemical properties at room temperature and require a certain reaction time at high temperature to achieve a complete oxidation reaction. If the reaction temperature is too low or the reaction time is too short (e.g., below 600℃ or less than 3h), the oxidation reaction may be incomplete, affecting the purity and yield of the product (i.e., tantalum pentoxide). If the reaction temperature is too high or the reaction time is too long (e.g., above 1100℃ or more than 12h), excessive production resources will be consumed, increasing production costs and reducing production efficiency. By setting the high-temperature condition to 600℃ to 1100℃ and the certain time to 3h to 12h, the oxidation reaction can proceed smoothly while simultaneously achieving the most complete oxidation process, the lowest possible production cost, and the highest possible production efficiency.

[0139] In some embodiments, the reaction temperature and reaction time can be related to the particle size of the powder. It is understood that, generally, the higher the reaction temperature, the longer the reaction time, and the finer the powder particle size, the more complete the oxidation reaction. To ensure the oxidation reaction proceeds fully, if the powder particle size is coarser, a higher reaction temperature and a longer reaction time can be set accordingly; if the powder particle size is finer, a lower reaction temperature and a shorter reaction time can be set accordingly. In some embodiments, by dynamically adjusting the reaction temperature, reaction time, and powder particle size, the highest possible product quality, the highest possible production efficiency, and the lowest possible production cost can be achieved.

[0140] In some embodiments, the powder of the ground target precipitate can be placed in a high-temperature treatment furnace, heated to 600℃~1100℃, and treated in a gaseous atmosphere such as air and oxygen for 3h~12h to obtain tantalum pentoxide powder. The carbon elemental powder in the powder can react with oxygen to generate gases such as carbon dioxide; the tantalum hydroxide powder, tantalum carbide powder, and tantalum elemental powder in the powder can react with oxygen to generate tantalum pentoxide powder.

[0141] In some embodiments, the purity of tantalum pentoxide powder may be not less than 99.99%. Preferably, the purity of tantalum pentoxide powder may be not less than 99.999%. It is understood that non-tantalum compounds (e.g., elemental carbon) contained in tantalum-containing waste have been removed as much as possible in the aforementioned steps, and no new impurities are introduced during the entire recycling and reuse process of tantalum-containing waste. Furthermore, the tantalum compounds have undergone sufficient oxidation reaction. Therefore, the purity of the generated tantalum pentoxide powder is also guaranteed.

[0142] Figure 5A is an X-ray diffraction (XRD) pattern of tantalum pentoxide powder according to some embodiments of this specification. As shown in Figure 5A, characteristic peaks of the (110), (002), and (211) crystal planes of tantalum pentoxide appear at 2θ of 28.2°, 37.8°, and 50.8°, respectively, indicating that the sample (i.e., the obtained tantalum pentoxide powder) contains tantalum pentoxide.

[0143] Figure 5B is the element list corresponding to Figure 5A, showing the elements found in the sample (i.e., the obtained tantalum pentoxide powder) and their proportions. Understandably, the relative atomic mass of oxygen is approximately 16, the relative atomic mass of tantalum is approximately 180.9, and the molecular weight of tantalum pentoxide is approximately 441.89. As shown in Figure 5B, the proportion of oxygen is 18.1%, and the proportion of tantalum is 81.9%, which is roughly the same as the relative atomic mass proportions of oxygen and tantalum atoms in the molecular weight of tantalum pentoxide. This indicates that the sample (i.e., the obtained tantalum pentoxide powder) is almost entirely composed of tantalum pentoxide, indicating a high purity.

[0144] Figure 5C is the pattern list corresponding to Figure 5A, presenting the elements found in the sample (i.e., the obtained tantalum pentoxide powder) and their proportions in the form of a pie chart. Refer to Figure 5B for specific interpretation methods, which will not be repeated here.

[0145] As shown in Figures 5A-5C, the final powder is composed of tantalum pentoxide with high purity, which can be used in the subsequent preparation of tantalum carbide coating.

[0146] In some embodiments, tantalum carbide raw materials can be prepared based on tantalum pentoxide powder. For example, a carbonaceous reducing agent is added to tantalum pentoxide powder, and a reduction reaction occurs under high temperature conditions to obtain tantalum carbide raw materials. In some embodiments, the obtained tantalum carbide raw materials can be applied to the aforementioned steps 410-450 to achieve the recycling and reuse of tantalum-containing waste. By preparing tantalum carbide raw materials based on tantalum pentoxide powder, tantalum pentoxide powder can be reprocessed into raw materials for the production of tantalum carbide coatings, realizing a closed loop in the entire recycling and reuse process.

[0147] By adding pure water to tantalum-containing waste, a mixture is obtained; an alkaline solution is added to the mixture to obtain a precipitate; the precipitate is filtered, washed, and dried to obtain the target precipitate; the target precipitate is ground into powder; in a high-temperature treatment device, a first target gas is introduced, and the powder is reacted under high-temperature conditions for a certain period of time to obtain tantalum pentoxide powder. On the one hand, this method can achieve the harmless treatment of tantalum-containing waste, transforming the stringent storage conditions (strict sealing, water avoidance, alkali avoidance, light avoidance, etc.) of tantalum-containing waste into simple and conventional storage conditions (dry storage is sufficient), reducing storage difficulty and costs. On the other hand, it transforms tantalum-containing waste with no or even negative value (such as incurring additional costs when handed over to waste disposal companies) into high-value-added tantalum pentoxide, realizing the recycling and reuse of tantalum element. By developing the utilization value of tantalum-containing waste, the overall production cost is reduced.

[0148] This specification provides one or more embodiments of an apparatus for growing silicon carbide. The surface of the apparatus is coated with a tantalum carbide coating prepared by the method for preparing a tantalum-containing coating as described in the embodiments of this specification. The apparatus includes one or more of the following: a crucible, a seed crystal holder, a lifting rod, a crystal growth furnace chamber, and a limiting component. Further details regarding the apparatus for growing silicon carbide can be found in Figure 1 and its related description.

[0149] This specification provides one or more embodiments of a tantalum carbide coating. The tantalum carbide coating is prepared using the tantalum-containing coating preparation method described in the embodiments of this specification.

[0150] Figure 6 is a flowchart of an exemplary method for recycling tantalum-containing waste generated during the preparation of tantalum-containing coatings according to some embodiments of this specification. As shown in Figure 6, process 600 includes the following steps.

[0151] Step 610: Add pure water to the tantalum-containing waste to obtain a mixture. In some embodiments, the tantalum-containing waste may include tantalum pentachloride, tantalum carbide, tantalum pentoxide, elemental tantalum, and elemental carbon. In some embodiments, the mixture may include the product of the reaction of tantalum pentachloride with pure water, tantalum carbide, tantalum pentoxide, elemental tantalum, and elemental carbon. For more details on step 610, please refer to the relevant description of step S1 in Figure 4.

[0152] Step 620: Add an alkaline solution to the mixture to obtain a precipitate. For more details on step 620, please refer to the relevant description of step S2 in Figure 4.

[0153] Step 630: Filter, wash, and dry the precipitate to obtain the target precipitate. For more details on step 630, please refer to the relevant description of step S3 in Figure 4.

[0154] Step 640: Grind the target precipitate to obtain powder. In some embodiments, this grinding may include grinding the target precipitate after a certain amount has been reached, where the certain amount is determined based on the maximum capacity of the high-temperature processing equipment. In some embodiments, the particle size of the powder may be 100 mesh to 800 mesh. For more details on step 640, please refer to the relevant description of step S4 in Figure 4.

[0155] Step 650: In a high-temperature processing device, a first target gas is introduced, and the powder is reacted under high-temperature conditions for a certain period of time to obtain tantalum pentoxide powder. In some embodiments, the first target gas may include one or more of air, oxygen, and ozone; the high-temperature conditions may be 600℃ to 1100℃; and the certain time may be 3h to 12h. In some embodiments, the purity of the tantalum pentoxide powder may be not less than 99.99%. For more details on step 650, please refer to the relevant description of step S5 in Figure 4.

[0156] Step 660: Prepare a tantalum carbide coating based on tantalum pentoxide powder.

[0157] In some embodiments, preparing a tantalum carbide coating based on tantalum pentoxide powder may include the following steps.

[0158] S101. Mix tantalum pentoxide powder with a carbonaceous reducing agent to obtain a mixture to be treated.

[0159] Carbonaceous reducing agents refer to reducing agents containing carbon. Examples include carbon black and carbon oxides. Mixtures to be treated refer to mixtures that require reduction treatment. Examples include mixtures of tantalum pentoxide powder and carbon black.

[0160] S102. In a high-temperature processing device, a second target gas is introduced, and the mixture to be processed is reacted at a certain temperature for a certain time to obtain tantalum carbide powder.

[0161] The second target gas refers to a gas capable of preventing oxidation reactions. In some embodiments, the second target gas may include one or more of hydrogen and inert gases. It is understood that introducing the second target gas allows air to escape from the high-temperature processing equipment, preventing the generated tantalum carbide powder from contacting oxygen in the air under high-temperature conditions and re-oxidizing into tantalum pentoxide powder; furthermore, when the second target gas is hydrogen, it possesses strong reducing properties, which facilitates the reduction reaction. A specific temperature and time can be set based on experience or requirements.

[0162] S103. A tantalum carbide coating is prepared using tantalum carbide powder as raw material via physical vapor deposition. For more details on step S103, please refer to the description of step 110 in Figure 1.

[0163] By mixing tantalum pentoxide powder with a carbonaceous reducing agent, a mixture to be treated is obtained; in a high-temperature treatment device, a second target gas is introduced, and the mixture to be treated is reacted at a certain temperature for a certain time to obtain tantalum carbide powder; using tantalum carbide powder as raw material, a tantalum carbide coating is prepared by physical vapor deposition, which can further generate the first tantalum carbide coating in the aforementioned step 110, realizing the recycling and reuse of tantalum-containing waste generated in the preparation of tantalum-containing coating.

[0164] In some embodiments, preparing a tantalum carbide coating based on tantalum pentoxide powder may include the following steps:

[0165] S201. Using tantalum pentoxide powder and a carbon source as raw materials, a tantalum carbide coating is prepared by a targeted method. In some embodiments, the targeted method includes one or more of the following: sol-gel method, spraying method, electrophoretic deposition method, solid-state reaction method, and self-propagating high-temperature synthesis method. For more details on step S201, please refer to the relevant description of step 120 in Figure 1.

[0166] By using tantalum pentoxide powder and carbon source as raw materials, a tantalum carbide coating can be prepared in a targeted manner, and the second tantalum carbide coating in step 120 can be further generated, thereby realizing the recycling and reuse of tantalum-containing waste generated in the preparation of the tantalum-containing coating.

[0167] In some embodiments, preparing a tantalum carbide coating based on tantalum pentoxide powder may include the following steps:

[0168] S301. Tantalum pentoxide powder is reacted with chlorine gas to produce tantalum pentachloride.

[0169] S302. Using tantalum pentachloride and a carbon source as raw materials, a tantalum carbide coating is prepared by chemical vapor deposition. For more details on step S302, please refer to the relevant description of step 130 in Figure 1.

[0170] By reacting tantalum pentoxide powder with chlorine gas, tantalum pentachloride is generated; using tantalum pentachloride and carbon source as raw materials, tantalum carbide coating is prepared by chemical vapor deposition, which can further generate the third tantalum carbide coating in step 130 above, realizing the recycling and reuse of tantalum-containing waste generated in the preparation of tantalum-containing coating.

[0171] In some embodiments of this specification, tantalum carbide coatings are prepared based on tantalum pentoxide powder. The tantalum pentoxide powder obtained from tantalum-containing waste can be put into the production process of the aforementioned first tantalum carbide coating, second tantalum carbide coating and third tantalum carbide coating, thereby realizing a closed loop of the entire recycling process.

[0172] In some embodiments of this specification, a mixture is obtained by adding pure water to tantalum-containing waste; an alkaline solution is added to the mixture to obtain a precipitate; the precipitate is filtered, washed, and dried to obtain a target precipitate; the target precipitate is ground to obtain powder; a first target gas is introduced into a high-temperature treatment device, and the powder is reacted under high-temperature conditions for a certain time to obtain tantalum pentoxide powder. This method can safely, conveniently, and cost-effectively recycle and reuse tantalum-containing waste generated during the preparation of tantalum carbide coatings, obtain high-purity tantalum oxide powder, and reuse it in the tantalum carbide coating preparation process, significantly improving the utilization rate of tantalum and reducing the cost of the tantalum carbide coating preparation process.

[0173] This specification provides one or more embodiments of an apparatus for growing silicon carbide. The surface of the apparatus is coated with a tantalum carbide coating prepared by an exemplary recycling method for tantalum-containing waste generated during the preparation of a tantalum-containing coating as described in the embodiments of this specification. The apparatus includes one or more of a crucible, a seed crystal holder, a lifting rod, a crystal growth furnace chamber, and a limiting element. Further details regarding the apparatus for growing silicon carbide can be found in Figure 1 and its related description.

[0174] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification. Although not explicitly stated herein, 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 and therefore remain within the spirit and scope of the exemplary embodiments described herein.

[0175] Furthermore, this specification uses specific terms to describe embodiments thereof. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of this specification. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Moreover, certain features, structures, or characteristics in one or more embodiments of this specification can be appropriately combined.

[0176] Furthermore, unless expressly stated in the claims, the order of processing elements and sequences, the use of numbers and letters, or other names described in this specification are not intended to limit the order of the processes and methods described herein. Although various examples have been discussed in the foregoing disclosure of some embodiments of the invention that are currently considered useful, it should be understood that such details are for illustrative purposes only, and the appended claims are not limited to the disclosed embodiments; rather, the claims are intended to cover all modifications and equivalent combinations that conform to the spirit and scope of the embodiments described herein. For example, while the system components described above can be implemented using hardware devices, they can also be implemented solely using software solutions, such as installing the described system on existing servers or mobile devices.

[0177] Similarly, it should be noted that, in order to simplify the description disclosed herein and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of embodiments in this specification may sometimes combine multiple features into a single embodiment, drawing, or description thereof. However, this method of disclosure does not imply that the subject matter of this specification requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of a single embodiment disclosed above.

[0178] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates 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 be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this specification are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0179] For each patent, patent application, patent application publication, and other material, such as articles, books, specifications, publications, and documents, referenced in this specification, the entire contents of which are incorporated herein by reference. This excludes historical application documents that are inconsistent with or conflict with the content of this specification, as well as documents that limit the broadest scope of the claims in this specification (currently or subsequently appended to this specification). It should be noted that in the event of any inconsistency or conflict between the descriptions, definitions, and / or terminology used in the supplementary materials to this specification and the content of this specification, the descriptions, definitions, and / or terminology used in this specification shall prevail.

[0180] Finally, it should be understood that the embodiments described in this specification are merely illustrative of the principles of the embodiments described herein. Other variations may also fall within the scope of this specification. Therefore, alternative configurations of the embodiments described herein are intended to be illustrative rather than limiting, and should be considered consistent with the teachings of this specification. Accordingly, the embodiments described herein are not limited to those explicitly introduced and described herein.

Claims

1. A method for preparing a tantalum-containing coating, characterized in that, The method includes: Using tantalum carbide as raw material, a first tantalum carbide coating is generated on the surface of a coating carrier through a first preparation method, wherein the first preparation method is physical vapor deposition (PVD). 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 by a second preparation method; 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 by a third preparation method, wherein the third preparation method is chemical vapor deposition (CVD).

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 μm.

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 0.05 μm to 1 μm, the thickness of the second tantalum carbide coating is 200 μm to 1000 μm, and the thickness of the third tantalum carbide coating is 20 μm to 80 μm.

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

6. The method according to claim 5, characterized in that, In the first tantalum source and the first carbon source, the molar ratio of carbon to tantalum 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 5 μm / h to 20 μm / h.

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

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

10. The method according to claim 1, characterized in that, The method further includes: Recover tantalum-containing waste generated during the preparation of the first, second, and third tantalum carbide coatings; and The tantalum-containing waste is recycled and reused.

11. The method according to claim 10, characterized in that, The recycling and reuse of the tantalum-containing waste includes: Pure water was added to the tantalum-containing waste to obtain a mixture; An alkaline solution was added to the mixture to obtain a precipitate; The precipitate is filtered, washed, and dried to obtain the target precipitate; The target precipitate was ground into powder; In a high-temperature processing device, a first target gas is introduced, and the powder is reacted under high-temperature conditions for a certain period of time to obtain tantalum pentoxide powder.

12. The method according to claim 11, characterized in that, The tantalum-containing waste includes tantalum pentachloride, tantalum carbide, tantalum pentoxide, elemental tantalum, and elemental carbon.

13. The method according to claim 12, characterized in that, The mixture includes the product of the reaction of tantalum pentachloride with the pure water, tantalum carbide, tantalum pentoxide, elemental tantalum, and elemental carbon.

14. The method according to claim 13, characterized in that, The first target gas includes one or more of air, oxygen, and ozone, the high temperature condition is 600℃~1100℃, and the certain time is 3h~12h.

15. The method according to claim 13, characterized in that, The grinding includes: After the target precipitate reaches a certain amount, the target precipitate is then ground. The certain amount is determined based on the maximum capacity of the high-temperature treatment equipment.

16. The method according to claim 15, characterized in that, The particle size of the powder is 100 mesh to 800 mesh.

17. The method according to claim 13, characterized in that, The purity of the tantalum pentoxide powder is not less than 99.99%.

18. The method according to claim 17, characterized in that, The method further includes: preparing tantalum carbide raw material based on the tantalum pentoxide powder.

19. An apparatus for growing silicon carbide, characterized in that, The surface of the device is covered with a tantalum carbide coating prepared by any one of the methods of claims 1-18, and the device includes one or more of a crucible, a seed crystal holder, a lifting rod, a crystal growth furnace chamber, and a limiting member.

20. A tantalum carbide coating, characterized in that, It is prepared by any one of claims 1-18.

21. A method for recycling and reusing tantalum-containing waste generated during the preparation of tantalum-containing coatings, characterized in that, The method includes: Pure water was added to the tantalum-containing waste to obtain a mixture; An alkaline solution was added to the mixture to obtain a precipitate; The precipitate is filtered, washed, and dried to obtain the target precipitate; The target precipitate was ground into powder; In a high-temperature processing device, a first target gas is introduced, and the powder is reacted under high-temperature conditions for a certain period of time to obtain tantalum pentoxide powder.

22. The method according to claim 21, characterized in that, The tantalum-containing waste includes tantalum pentachloride, tantalum carbide, tantalum pentoxide, elemental tantalum, and elemental carbon.

23. The method according to claim 22, characterized in that, The mixture includes the product of the reaction of tantalum pentachloride with the pure water, tantalum carbide, tantalum pentoxide, elemental tantalum, and elemental carbon.

24. The method according to claim 23, characterized in that, The first target gas includes one or more of air, oxygen, and ozone, the high temperature condition is 600℃~1100℃, and the certain time is 3h~12h.

25. The method according to claim 23, characterized in that, The grinding includes: After the target precipitate reaches a certain amount, the target precipitate is then ground. The certain amount is determined based on the maximum capacity of the high-temperature treatment equipment.

26. The method according to claim 25, characterized in that, The particle size of the powder is 100 mesh to 800 mesh.

27. The method according to claim 23, characterized in that, The purity of the tantalum pentoxide powder is not less than 99.99%.

28. The method according to claim 27, characterized in that, The method further includes: preparing the tantalum carbide coating based on the tantalum pentoxide powder.

29. The method according to claim 28, characterized in that, The preparation of the tantalum carbide coating based on the tantalum pentoxide powder includes: The tantalum pentoxide powder is mixed with a carbonaceous reducing agent to obtain a mixture to be treated; In the high-temperature processing equipment, a second target gas is introduced, and the mixture to be processed is reacted at a certain temperature for a certain time to obtain tantalum carbide powder. The second target gas includes one or more of hydrogen and inert gases. The tantalum carbide coating was prepared by physical vapor deposition using the tantalum carbide powder as raw material.

30. The method according to claim 28, characterized in that, The preparation of the tantalum carbide coating based on the tantalum pentoxide powder includes: The tantalum carbide coating is prepared using the tantalum pentoxide powder and carbon source as raw materials through a targeted method, which includes one or more of the following: sol-gel method, spraying method, electrophoretic deposition method, solid-state reaction method, and self-propagating high-temperature synthesis method.

31. The method according to claim 28, characterized in that, The preparation of the tantalum carbide coating based on the tantalum pentoxide powder includes: The tantalum pentoxide powder is reacted with chlorine gas to generate tantalum pentachloride; The tantalum carbide coating was prepared by chemical vapor deposition using tantalum pentachloride and a carbon source as raw materials.

32. An apparatus for growing silicon carbide, characterized in that, The surface of the device is covered with the tantalum carbide coating prepared by any one of the methods of claims 21-31, and the device includes one or more of the following: crucible, seed crystal holder, lifting rod, crystal growth furnace chamber, and limiting member.

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