A protective coating for an electronic-grade halide preparation apparatus and its preparation method and apparatus

Abstract

This invention provides a protective coating and its preparation method and apparatus for an electronic-grade halide preparation device. The coating is obtained by thermal spraying of nickel-based alloy powder. By mass percentage, the nickel-based alloy powder comprises: 18-25% Cr, 18-20% Mo, 5-8% W, and 1-3% Co, with the balance being Ni and unavoidable impurities. The high Cr content forms a dense Cr2O3 passivation film in situ under corrosive conditions to block media erosion; Mo significantly improves resistance to pitting and crevice corrosion; W synergistically repairs passivation film defects and enhances its stability; and Co further improves the coating's high-temperature corrosion resistance. The synergistic effect of these four components ensures long-term corrosion protection, completely eliminates the precipitation of metallic impurities caused by substrate corrosion, and guarantees the purity of high-purity halides. Furthermore, this coating achieves excellent performance without relying on high-temperature vacuum heat treatment, making it more suitable for surface protection of large components.

Description

Technical Field

[0001] This invention relates to the field of surface engineering technology, and more specifically, to a protective coating for an electronic-grade halide preparation apparatus, as well as a preparation method and apparatus. Background Technology

[0002] Electronic-grade halides such as hydrogen chloride (HCl), hydrogen bromide (HBr), and hydrogen fluoride (HF) are indispensable specialty gas raw materials for key processes such as semiconductor chip etching and microelectronic device cleaning. As integrated circuit manufacturing processes continue to shrink, the purity requirements for gases have increased to 5N (99.999%) and even 6N levels, and even trace amounts of metallic impurities in the medium can cause chip short circuits or render them unusable. In the refining process of electronic-grade halides, the crude raw material needs to undergo deep dehydration and purification processes such as adsorption and distillation. However, due to limitations in current technology, absolutely anhydrous conditions cannot be achieved in production. Trace amounts of moisture combine with gaseous halides to form strong acids (such as hydrobromic acid and hydrofluoric acid), causing severe pitting and intergranular corrosion on the inner walls of equipment such as distillation columns, adsorption columns, and buffer tanks. This corrosion not only threatens the safe operation of equipment but also causes metallic components in the substrate to dissolve into the medium, resulting in irreversible contamination of high-purity products.

[0003] Patent application number 202511188796.2 discloses a double-layer nickel-based protective coating, which consists of a Ni-Cr-Nb bonding layer and a Ni-Cr-Mo-W functional layer. It is suitable for boiler superheaters and reheaters operating under conditions of high temperature above 600℃, synergistic corrosion of chlorine and sulfur flue gas, and high-speed flue gas scouring. The coating contains a variety of alloying elements such as Nb, Ti, B, Si and rare earth elements. In the activated corrosion environment formed by electronic-grade halides encountering water, the above components are prone to slight dissolution, which can contaminate high-purity electronic gases. Patent application number 202310262221.5 discloses a high-temperature hydrochloric acid corrosion resistant coating and its preparation method. The coating is a Ni-Mo based high-temperature alloy coating, with the components by mass fraction as Mo: 28%, Fe: 1.5%, Cr: 0.5%, and the balance being nickel. This scheme adopts a supersonic flame spraying process followed by a vacuum heat treatment process. By controlling the heat treatment parameters, the excessive diffusion of C and Fe from the ductile iron matrix into the coating is suppressed. The optimized coating has excellent corrosion resistance under 60℃ and 15wt% aqueous hydrochloric acid conditions. However, this process requires a dedicated high-temperature vacuum heat treatment furnace, which can only process small samples. Furthermore, this formula cannot generate a stable and continuous passivation film. During long-term service, the coating is prone to micropore formation, which leads to acid penetration into the metal matrix.

[0004] Therefore, there is an urgent need for a protective coating for electronic-grade halide preparation devices that is simple in composition, requires no high-temperature vacuum heat treatment, and has long-lasting corrosion resistance. Summary of the Invention

[0005] In view of this, the present invention aims to provide a protective coating for an electronic-grade halide preparation device and its preparation method, so as to solve the problems of existing corrosion-resistant coatings having complex composition, requiring high-temperature vacuum heat treatment, and having poor long-term corrosion resistance.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0007] This invention provides a protective coating for an electronic-grade halide preparation device, wherein the coating is obtained by thermal spraying of nickel-based alloy powder; the nickel-based alloy powder comprises, by mass percentage: Cr 18-25%, Mo 18-20%, W 5-8%, Co 1-3%, with the balance being Ni and unavoidable impurities.

[0008] This invention utilizes a rational ratio of four elements: Cr, Mo, W, and Co. A high Cr content allows for the formation of a dense Cr2O3 passivation film under dilute HBr conditions, effectively blocking erosion. Mo enhances the coating's resistance to pitting and crevice corrosion. W works synergistically with Mo to repair passivation film defects and strengthen its stability. Co improves the coating's high-temperature corrosion resistance. The components work together to achieve long-term corrosion protection, preventing the substrate from corroding and precipitating metallic impurities that contaminate high-purity halides, and eliminating the need for high-temperature vacuum heat treatment.

[0009] Furthermore, by mass percentage, the nickel-based alloy powder consists of the following components: Cr 20-25%, Mo 18-19.5%, W 5-8%, Co 1-2.5%, with the balance being Ni and unavoidable impurities.

[0010] Furthermore, the impurities in the nickel-based alloy powder are C and O; by mass percentage, O ≤ 0.035% and C ≤ 0.02%.

[0011] This application limits the upper limit of C and O impurity content to prevent impurities from forming carbide and oxide inclusions that could create corrosion channels, reduce internal defects in the coating, effectively reduce the risk of corrosive media penetration, and improve the long-term corrosion resistance stability of the coating.

[0012] Furthermore, the nickel-based alloy powder is prepared by mechanically mixing elemental metal powders of nickel, chromium, molybdenum, tungsten, and cobalt.

[0013] This invention uses mechanical mixing of various elemental metal powders to produce powder, eliminating the alloy smelting process. The preparation process is simple and flexible, making it more suitable for small-batch, low-cost production.

[0014] Furthermore, the nickel-based alloy powder is obtained by melting raw materials containing nickel, chromium, molybdenum, tungsten and cobalt together to form an alloy melt, which is then atomized and sieved.

[0015] This invention involves melting metal raw materials and then atomizing them into powder. The powder has a uniform composition without segregation, making it more suitable for large-scale mass production.

[0016] Furthermore, the particle size of the nickel-based alloy powder is 15–100 μm.

[0017] This invention controls the powder particle size within the range of 15 to 100 μm, which avoids both excessively small particle size leading to high-temperature oxidation of the powder and excessively large particle size leading to poor powder melting. At the same time, it can be adapted to various spraying processes, resulting in a coating surface with fewer voids.

[0018] In this invention, the particle size of the nickel-based alloy powder is preferably 15-60 μm.

[0019] The present invention preferably uses powder particles with a particle size of 15 to 60 μm. Such powder melts more fully during the spraying process, has a lower degree of oxidation, and has a lower porosity and further improved density after deposition and molding, thereby significantly enhancing the coating's resistance to erosion and corrosion.

[0020] Furthermore, the thickness of the coating is 0.15 to 1.5 mm.

[0021] This design prevents the coating from being damaged and perforated by the erosion and wear of catalyst particles if it is too thin, while avoiding excessive residual stress caused by excessive coating thickness, which can lead to cracking and failure. It effectively blocks corrosive media from penetrating the substrate and prevents the substrate from dissolving metal impurities that contaminate electronic-grade halide products.

[0022] In this invention, the thickness of the coating is preferably 0.15 to 1 mm.

[0023] This invention also provides a method for preparing a protective coating for an electronic-grade halide preparation device, used to prepare the coating described in the above technical solution, specifically including the following steps:

[0024] S1. Preparation of nickel-based alloy powder

[0025] Nickel-based alloy powder was prepared according to the specified ratio, wherein the particle size of the nickel-based alloy powder was 15–100 μm;

[0026] S2, Substrate Pretreatment

[0027] The surface of the substrate is cleaned and roughened.

[0028] S3, Coating Forming

[0029] The nickel-based alloy powder is fed into a heat source to melt or partially melt using a thermal spraying process, and then sprayed at high speed onto the surface of the pretreated substrate to form an initial protective coating of a predetermined thickness.

[0030] Furthermore, in step S3, an initial protective coating is prepared using plasma spraying, supersonic flame spraying, or laser cladding processes;

[0031] The parameters for the plasma spraying process are: spraying power 30kW~35kW, powder feed rate 30g / min~40g / min; the parameters for the supersonic flame spraying process are: kerosene flow rate 25L / h~30L / h, oxygen flow rate 50m³ / h. 3 / h~60m 3 / h; The parameters of the laser cladding process are: laser power 3.0kW~5.0kW, scanning rate 1000mm / s~1500mm / s.

[0032] In this invention, when plasma spraying and supersonic flame spraying are used, step S3 preferably further includes:

[0033] S4, Sealing treatment

[0034] The surface of the initial protective coating is sealed with a sealing agent to improve its corrosion resistance.

[0035] In this invention, step S3 or S4 preferably further includes:

[0036] S5, Precision machining

[0037] The coating surface is processed by grinding and polishing to achieve the preset required dimensions and surface condition.

[0038] It should be noted that pore sealing is a post-treatment process in which a pore-sealing agent penetrates into the micropores of the coating and cures, filling and sealing the pores. This method can seal the interconnected pores of the coating, preventing corrosive media such as HBr from penetrating into the substrate and corroding it, while also preventing metal ions from dissolving and contaminating electronic-grade halides, thus improving the overall corrosion resistance of the coating. Plasma spraying and supersonic flame spraying rely on the stacking of molten particles to form the coating, resulting in interconnected pores within the coating. Corrosive media can easily penetrate into the substrate through these pores, thus requiring pore sealing. In particular, the finishing grinding process of plasma spraying can expose new pores, necessitating secondary pore sealing. Laser cladding, on the other hand, achieves a metallurgical bond between the coating and the substrate, resulting in a dense coating without interconnected pores. Corrosive media cannot penetrate inwards, and the coating's structure alone is sufficient to isolate it, eliminating the need for pore sealing.

[0039] In this invention, the sealing agent is preferably an organosilicon precursor, model DM4000.

[0040] In this invention, in step S2, chemical cleaning is preferably used to remove oil stains from the substrate surface; sandblasting is preferably used to remove impurities and roughen the surface, removing rust, oxide scale and dirt, while creating a micro-rough surface to improve the interfacial bonding strength.

[0041] It should be noted that the present invention does not impose any special limitations on the material of the substrate, and various metal substrates can be used to prepare the coating; in actual industrial production applications, iron-based alloy steels such as Q245R and 304L are preferred as the substrate.

[0042] The present invention also provides an electronic-grade halide preparation apparatus, comprising at least one of a tower body, a tank body, a flange, and a blind flange; the inner wall surfaces of the tower body, the tank body, the flange, and the blind flange are all provided with the coating described in the above technical solution.

[0043] Compared with existing technologies, the protective coating for electronic-grade halide preparation apparatus and its preparation method described in this invention have the following advantages:

[0044] This invention utilizes a synergistic corrosion-resistant system formed by the rational proportioning of Cr, Mo, W, and Co elements. This system can prepare protective coatings on the surfaces of conventional, inexpensive iron-based substrates such as Q245R and 304L, significantly reducing equipment costs compared to using Hastelloy as the sole material. The resulting coating exhibits superior resistance to hydrobromide corrosion compared to Hastelloy C276, effectively preventing the leaching of metallic impurities from the substrate and ensuring the purity of electronic-grade halide products. It is compatible with various electronic-grade halide preparation equipment components, such as tanks and flanges, and offers a long overall protective lifespan. Attached Figure Description

[0045] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0046] Figure 1 The SEM image of the cross-section of the coating prepared in Example 4;

[0047] Figure 2 The SEM image of the cross-section of the coating prepared in Example 5;

[0048] Figure 3 These are comparative photographs of the HBr immersion solutions of Example 5 and Comparative Example 1 after 360h and 122h corrosion tests. Detailed Implementation

[0049] The present invention will be further described below with reference to specific embodiments. First, it should be noted that the data in the following experimental examples were obtained by the inventors through numerous experiments. Due to space limitations, only a portion of these data is shown in the specification, and those skilled in the art can understand and implement the present invention based on this data. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the contents of this invention, those skilled in the art can make various modifications or alterations to the invention, and these modifications or alterations also fall within the scope of protection of this application.

[0050] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0051] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0052] High-purity specialty corrosive gases such as electronic-grade hydrogen bromide, hydrogen chloride, and hydrogen fluoride are indispensable basic materials for core processes in semiconductor manufacturing, microelectronics cleaning, and etching. Their purity standards are extremely high (typically ≥99.999%, some reaching 99.9999%), and the control of metallic impurities and particulate matter is extremely stringent. Currently, the industrial preparation of these gases requires deep purification through synthesis, adsorption, distillation, filtration, and filling. However, in actual production, if trace amounts of moisture (ppm level) remain in the system, it can not only induce severe intergranular corrosion in 316L stainless steel, causing serious metallic impurity contamination, but also lead to leakage of toxic materials due to equipment corrosion and perforation, posing significant safety and environmental risks.

[0053] This embodiment provides a protective coating for an electronic-grade halide preparation device. The coating is formed by thermal spraying of nickel-based alloy powder. By mass percentage, the composition of the nickel-based alloy powder includes: Cr 18-25%, Mo 18-20%, W 5-8%, Co 1-3%, with the balance being Ni and unavoidable impurities.

[0054] This embodiment also provides a method for preparing a protective coating for an electronic-grade halide preparation device, used to prepare the coating described in the above technical solution, specifically including the following steps:

[0055] S1. Preparation of nickel-based alloy powder

[0056] Nickel-based alloy powder was prepared according to the specified ratio, wherein the particle size of the nickel-based alloy powder was 15 μm to 100 μm;

[0057] S2, Substrate Pretreatment

[0058] The surface of the substrate is cleaned and roughened.

[0059] S3, Coating Forming

[0060] The nickel-based alloy powder is fed into a heat source to melt or partially melt using a thermal spraying process, and then sprayed at high speed onto the surface of the pretreated substrate to form an initial protective coating of a predetermined thickness.

[0061] The nickel-based alloy described in this embodiment uses a precise blend of four alloying elements—Cr, Mo, W, and Co—to synergistically construct a stable, corrosion-resistant passivation system suitable for high-temperature corrosion conditions involving trace amounts of electronic-grade hydrogen halides in water. The mechanisms of action of each element are as follows:

[0062] Chromium (Cr): High Cr content in the coating can continuously generate a dense and stable Cr2O3 passivation film on the coating surface in the hydrogen halide corrosion environment, which isolates corrosive media such as HBr and HCl from contact with the base alloy, blocks the media from eroding inward from the source, and improves the overall resistance to uniform corrosion.

[0063] Molybdenum (Mo): Mo can significantly optimize the alloy's resistance to localized corrosion, greatly improve the coating's resistance to pitting and crevice corrosion in water-containing HBr media, and prevent the medium from causing perforation corrosion at microscopic defects in the coating.

[0064] Tungsten (W): W and Mo form a synergistic effect, preferentially enriching and repairing the passivation film in the pores and defect sites of the Cr2O3 passivation film, enhancing the structural integrity and stability of the passivation film, and further inhibiting the initiation of local corrosion.

[0065] Cobalt (Co): Improves the high-temperature structural stability of alloys, enhances the corrosion resistance of coatings under long-term high-temperature operation conditions of equipment, and prevents passivation film failure and peeling in high-temperature environments.

[0066] After the above elements are properly proportioned, the coating passivation film is dense and long-lasting, which can effectively prevent halide corrosive media from penetrating the coating and eroding the Q245R and 304L substrates, and avoid the substrate corrosion leaching out metal impurities to contaminate high-purity electronic-grade halide products; at the same time, the coating is resistant to high temperature and media erosion, and can replace expensive Hastelloy integral parts, significantly reducing equipment production costs.

[0067] It should be noted that in this embodiment, C and O are unavoidable impurities in the preparation process, and the impurity content is controlled to be C≤0.02wt% and O≤0.035wt%. The sealing agent used in this invention is an organosilicon precursor, model DM4000, which can be purchased directly from the market and will not be described in detail later.

[0068] Example 1

[0069] This embodiment provides a method for preparing a protective coating for an electronic-grade halide preparation device. The method employs an atmospheric plasma spraying process to apply the coating to the flange interface surface of the DN250 adsorbent unloading pipe at the bottom (or side) of the adsorption tower, specifically including the following steps:

[0070] S1. Preparation of nickel-based alloy powder

[0071] According to the mass ratio shown in Table 1 below, weigh out elemental metal powders of Ni, Cr, Mo, W and Co with a particle size of 40-70 μm, place the powders in a V-type mixer and mix them thoroughly to obtain nickel-based alloy powder for later use.

[0072] Table 1. Chemical composition of the nickel-based alloy powders described in Examples 1-3

[0073] Element Ni Cr Mo W Co O C Content (wt%) margin 18～25 18～20 5～8 1～3 ≤0.035% ≤0.02%

[0074] S2, Substrate Pretreatment

[0075] First, the flange is machined, and machining allowance is reserved for the inner and outer diameters of the flange sealing surface according to the target coating thickness. Then, the area to be coated is cleaned with alcohol and acetone to remove oil and wipe it clean, and the surface is strictly checked for defects such as sand holes and pits that may affect the coating quality. Finally, the area to be coated is sandblasted and roughened with 24-mesh brown corundum, and the sandblasting pressure is controlled at 0.6-0.8MPa, and the sandblasting distance is kept within the range of 150±50mm.

[0076] S3, Coating Forming:

[0077] The mechanically mixed nickel-based alloy powder is loaded into a powder feeding cylinder and deposited on the pretreated flange surface using an atmospheric plasma spraying process. The process parameters for this stage are set as follows: spraying power 32kW, main air flow rate 50L / min, powder feed rate 35g / min, spraying distance 130mm, and multiple spraying passes are used to achieve a rough coating thickness of 0.4mm.

[0078] S4. Sealing treatment:

[0079] Immediately after spraying, an organosilicon precursor is used to seal the surface of the rough coating to initially close the micropores inside the coating.

[0080] S5. Finishing process:

[0081] After the coating has cooled, the surface of the coating is treated by a combination of grinding and polishing to precisely control the final coating thickness to 0.30 mm and make the surface roughness meet the design requirement of Ra0.4 μm.

[0082] S6. Secondary sealing treatment:

[0083] The coated surface, after fine machining, undergoes a second sealing process to completely eliminate the tiny pores exposed by machining, ensuring the ultimate density and corrosion resistance of the coating surface.

[0084] This flange was assembled into an electronic-grade hydrogen bromide industrial production line and put into continuous operation. It was in long-term contact with high-purity HBr corrosive media containing trace amounts of water. After 3600 hours of continuous operation, it was disassembled and inspected. The coating on the inner wall of the flange was intact and without corrosion or damage. The halide products produced had no problem with excessive metal impurities. The corrosion rate of the coating was only 20 / 1 of that of 304 stainless steel. The expected service life is more than 10 years.

[0085] Example 2

[0086] This embodiment provides a method for preparing a protective coating for an electronic-grade halide preparation device. The method employs a supersonic flame spraying process to apply the coating to the inner wall of a buffer tank with dimensions Φ1400×1600mm, and specifically includes the following steps:

[0087] S1. Preparation of nickel-based alloy powder

[0088] According to the mass ratio shown in Table 1, nickel-based alloy powder with a particle size of 15-45 μm was prepared by using a process of co-melting raw materials, gas atomization and sieving.

[0089] S2, Substrate Pretreatment

[0090] First, inspect the inner wall of the buffer tank and grind away surface defects such as welding slag and sand holes; then use alcohol and acetone to clean and degrease the areas to be coated; finally, use 16-40 mesh brown corundum to sandblast and purify the inner wall of the tank, controlling the sandblasting pressure at 0.6-0.8 MPa and maintaining the sandblasting distance within the range of 200±100 mm.

[0091] S3, Coating Forming

[0092] Nickel-based alloy powder prepared by gas atomization was loaded into a powder feeding cylinder and deposited on the pretreated tank surface using a supersonic flame spraying process. The process parameters for this stage were set as follows: kerosene flow rate 28 L / h, oxygen flow rate 55 m³ / h, powder feeding rate 35 g / min, and spraying distance 380 mm. Through multiple spraying passes, the coarse coating thickness reached 0.3 mm.

[0093] S4, Sealing treatment

[0094] Immediately after spraying, an organosilicon precursor is used to seal the surface of the rough coating, thereby sealing the micropores inside the coating.

[0095] The buffer tank was directly put into the electronic-grade halide production line to hold crude hydrogen halide raw materials. It ran continuously at full load for 3600 hours. The coating on the inner wall of the tank showed no pitting or peeling. The content of metallic impurities in the finished gas met the high purity index for electronic grade. The corrosion rate of the coating was only 1 / 25 of that of 304 stainless steel. The expected service life is more than 10 years.

[0096] Example 3

[0097] This embodiment provides a method for preparing a protective coating for an electronic-grade halide preparation device. The method employs a laser cladding process to apply the coating to the media contact surface of a DN400 blind flange, specifically including the following steps:

[0098] S1. Preparation of nickel-based alloy powder

[0099] According to the mass ratio shown in Table 1, nickel-based alloy powder with a particle size of 50-100 μm was prepared by using a process of co-melting raw materials, gas atomization and sieving.

[0100] S2, Substrate Pretreatment

[0101] First, the sealing surface of the blind flange is machined, leaving machining allowance according to the subsequent coating thickness requirements; then, the cladding area is cleaned by wiping with alcohol and acetone to remove oil, and the surface is strictly inspected for defects such as sand holes and pits that may affect the coating quality; finally, the coated area is sandblasted and roughened with 40-50 mesh brown corundum, with the sandblasting pressure controlled at 0.5-0.7 MPa and the sandblasting distance maintained within the range of 150±50 mm.

[0102] S3, Coating Forming

[0103] Nickel-based alloy powder prepared by gas atomization was loaded into a powder feeding cylinder. Using laser cladding, a pure nickel underlayer with a thickness of 200 μm was first prepared on the substrate surface; then a nickel-based alloy protective layer was deposited. The process parameters for this stage were set as follows: laser power 4.0 kW, scanning rate 1200 mm / s, powder feed rate 13 g / min, and cladding overlap rate 45%.

[0104] S4, Fine machining

[0105] After the coating has cooled, the surface of the coating is treated by a combination of grinding and polishing to precisely control the final coating thickness to 0.75 mm and make the surface roughness meet the design requirement of Ra0.4 μm.

[0106] The blind flange was installed at a critical location in the halide distillation pipeline and operated continuously for 3600 hours. The sealing surface coating remained intact and free from corrosion. The produced high-purity halides showed no metal ion leaching contamination. The corrosion rate of the coating was only 18 / 1 that of 304 stainless steel, and its expected service life is more than 10 years.

[0107] Example 4

[0108] This embodiment provides a method for preparing a protective coating for an electronic-grade halide preparation device, specifically including the following steps:

[0109] S1. Preparation of nickel-based alloy powder

[0110] According to the mass ratio of Cr: 20.6%, Mo: 19.2%, W: 7.3%, Co: 2.2%, and the balance being Ni (O≤0.035%, C≤0.02%), nickel-based alloy powder with a particle size of 15-45μm was prepared by using a process of co-melting of raw materials, gas atomization, and sieving.

[0111] S2, Substrate Pretreatment

[0112] 304L stainless steel is used as the base material. After checking for defects on the surface of the base material, it is polished.

[0113] S3, Coating Forming

[0114] Nickel-based alloy powder prepared by gas atomization was loaded into a powder feeding cylinder and deposited on the pretreated substrate surface using a supersonic flame spraying process. The process parameters for this stage were set as follows: kerosene flow rate 29 L / h, oxygen flow rate 53 m³ / h. 3 With a powder feed rate of 34g / min and a spraying distance of 400mm, the coarse coating thickness reaches 0.26-0.28mm through multiple spraying passes.

[0115] S4, Sealing treatment

[0116] Immediately after spraying, an organosilicon precursor was used to seal the surface of the rough coating, thereby sealing the micropores inside the coating and obtaining a substrate sample with a protective coating, which was designated as sample 1.

[0117] Metallographic specimens were prepared from sample 1 and scanned electron microscope images were taken. The results are as follows: Figure 1 As shown. From Figure 1 It can be seen that the coating has a uniform and dense structure with few pores, and the interface between the coating and the substrate is intact.

[0118] Sample 1 was placed in a boiling HBr solution with a mass fraction of 0.5% for a 360-hour accelerated corrosion test. Compared with the actual industrial environment, the acceleration ratio was 150 to 200 times. After the test, the coating was intact and had no corrosion defects. The immersion solution did not change color and there was no precipitation or dissolution of metal ions.

[0119] Example 5

[0120] This embodiment provides a method for preparing a protective coating for an electronic-grade halide preparation device, specifically including the following steps:

[0121] S1. Preparation of nickel-based alloy powder

[0122] According to the mass ratio of Cr: 24.8%, Mo: 18.1%, W: 5.2%, Co: 1.0%, and the balance being Ni (O≤0.035%, C≤0.02%), Ni, Cr, Mo, W, and Co elemental metal powders with a particle size of 40-70 μm were weighed and placed in a V-type mixer for thorough and uniform mixing to obtain nickel-based alloy powder for later use.

[0123] S2, Substrate Pretreatment

[0124] 304L stainless steel is used as the base material. After checking for defects on the surface of the base material, it is polished.

[0125] S3, Coating Forming:

[0126] Mechanically mixed nickel-based alloy powder is loaded into a powder feeding cylinder and deposited onto the pretreated substrate surface using an atmospheric plasma spraying process. The process parameters for this stage are set as follows: spraying power 35kW, main air flow rate 50L / min, powder feed rate 38g / min, and spraying distance 120mm. Through multiple spraying passes, the coarse coating thickness reaches 0.32-0.33mm.

[0127] S4. Sealing treatment:

[0128] Immediately after spraying, an organosilicon precursor was used to seal the surface of the rough coating to initially seal the micropores inside the coating, thus obtaining a substrate sample with a protective coating, denoted as Sample 2.

[0129] Sample 2 was taken to prepare a metallographic specimen and scanned electron microscope images were taken. The results are as follows: Figure 2 As shown. From Figure 2 It can be seen that the coating has a uniform and dense structure with few pores, and the interface between the coating and the substrate is intact.

[0130] Sample 2 was placed in a boiling HBr solution with a mass fraction of 0.5% for a 360-hour accelerated corrosion test. After the test, the coating was intact and had no corrosion defects. The immersion solution did not change color and there was no precipitation or dissolution of metal ions.

[0131] Comparative Example 1

[0132] The same preparation method as in Example 5 was used, except that in step S1, nickel-based alloy powder was prepared according to the mass ratio of Cr: 17.8%, Mo: 16.9%, W: 4.2%, Co: 0.9%, with the balance being Ni (O≤0.035%, C≤0.02%), to obtain sample 3.

[0133] Sample 3 was placed in a boiling HBr solution with a mass fraction of 0.5% for a 360-hour accelerated corrosion test. After 122 hours, the coating corroded and the solution changed color.

[0134] Comparative Example 2

[0135] The same preparation method as in Example 5 was used, except that in step S1, nickel-based alloy powder was prepared according to the mass ratio of Cr: 22.1%, Mo: 15.4%, W: 3.2%, Co: 0.5%, with the balance being Ni (O≤0.035%, C≤0.02%), to obtain sample 4.

[0136] Sample 4 was placed in a boiling HBr solution with a mass fraction of 0.5% for a 360-hour accelerated corrosion test. After 98 hours, the coating corroded and the solution changed color.

[0137] Comparative Example 3

[0138] The same preparation method as in Example 4 was used, except that in step S1, nickel-based alloy powder was prepared according to the mass ratio of Cr: 20.0%, Mo: 18.3%, W: 3.3%, Co: 0.7%, with the balance being Ni (O≤0.035%, C≤0.02%), and sample 5 was obtained.

[0139] Sample 5 was placed in a boiling HBr solution with a mass fraction of 0.5% for a 360-hour accelerated corrosion test. After 73 hours, the coating corroded and the solution changed color.

[0140] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A protective coating for an electronic-grade halide preparation apparatus, characterized in that, The coating is obtained by thermal spraying of nickel-based alloy powder; by mass percentage, the composition of the nickel-based alloy powder includes: Cr 18-25%, Mo 18-20%, W 5-8%, Co 1-3%, with the balance being Ni and unavoidable impurities.

2. The coating according to claim 1, characterized in that, The nickel-based alloy powder, by mass percentage, consists of the following components: Cr 20-25%, Mo 18-19.5%, W 5-8%, Co 1-2.5%, with the balance being Ni and unavoidable impurities.

3. The coating according to claim 1 or 2, characterized in that, The impurities in the nickel-based alloy powder are C and O; by mass percentage, O ≤ 0.035% and C ≤ 0.02%.

4. The coating according to claim 1, characterized in that, The nickel-based alloy powder is prepared by mechanically mixing elemental metal powders of nickel, chromium, molybdenum, tungsten, and cobalt.

5. The coating according to claim 1, characterized in that, The nickel-based alloy powder is obtained by melting raw materials containing nickel, chromium, molybdenum, tungsten and cobalt together to form an alloy melt, which is then atomized and sieved.

6. The coating according to claim 1, characterized in that, The particle size of the nickel-based alloy powder is 15–100 μm.

7. The coating according to claim 1, characterized in that, The thickness of the coating is 0.15 to 1.5 mm.

8. A method for preparing a protective coating for an electronic-grade halide preparation apparatus, characterized in that, The method for preparing the coating according to any one of claims 1 to 7 specifically includes the following steps: S1. Preparation of nickel-based alloy powder Nickel-based alloy powder was prepared according to the specified ratio, wherein the particle size of the nickel-based alloy powder was 15–100 μm; S2, Substrate Pretreatment The surface of the substrate is cleaned and roughened. S3, Coating Forming The nickel-based alloy powder is fed into a heat source to melt or partially melt using a thermal spraying process, and then sprayed at high speed onto the surface of the pretreated substrate to form an initial protective coating of a predetermined thickness.

9. The preparation method according to claim 8, characterized in that, In step S3, an initial protective coating is prepared using plasma spraying, supersonic flame spraying, or laser cladding processes; The parameters for the plasma spraying process are: spraying power 30kW~35kW, powder feed rate 30g / min~40g / min; the parameters for the supersonic flame spraying process are: kerosene flow rate 25L / h~30L / h, oxygen flow rate 50m³ / h. 3 / h~60m 3 / h; The parameters of the laser cladding process are: laser power 3.0kW~5.0kW, scanning rate 1000mm / s~1500mm / s.

10. An apparatus for preparing electronic-grade halides, characterized in that, It includes at least one of a tower body, a tank body, a flange, and a blind flange; the inner wall surfaces of the tower body, the tank body, the flange, and the blind flange are all provided with the coating described in any one of claims 1 to 7.

Images