PRODUCTION OF A COATING WITH HIGH-TEMPERATURE CORROSION RESISTANCE AND WEAR RESISTANCE

Description

2 CONTENT OF THE PRESENT INVENTION The objective of the present invention is to provide a method for producing a coating with high-temperature corrosion resistance and wear resistance in order to solve the aforementioned problems in the prior art. To achieve the aforementioned objective, the present invention offers the following five solutions. Technical Solution of the Present Invention: A coating with high-temperature corrosion resistance and wear resistance is provided, wherein the coating with high-temperature corrosion resistance and wear resistance is a NiCrAlY-TiC composite coating consisting of a NiCrAlY alloy phase and a dispersed TiC ceramic reinforcing phase. Preferably, the thickness of the coating with high-temperature corrosion resistance and wear resistance is 0.2–1 mm.Technical Solution II of the present invention: A method for producing the aforementioned coating with high-temperature corrosion resistance and wear resistance is provided, comprising the following steps: mixing a NiCrAlY alloy powder with a TiC ceramic powder to obtain a composite powder; and bonding the composite powder to a substrate by means of high-speed laser cladding under an inert atmosphere to form a coating on the surface of the substrate and thus obtain the coating with high-temperature corrosion resistance and wear resistance. The present invention utilizes high-speed laser cladding technology for the production of coatings. High-speed laser cladding offers advantages such as a small heat-affected zone and a low dilution rate.It reduces the impact on the substrate material and simultaneously ensures the purity and performance of a coating layer, thereby allowing the properties of the coatings to be optimally utilized. Preferably, the mass of the TiC ceramic powder is 0.2–2% of the total mass of the NiCrAlY alloy powder and the TiC ceramic powder. Preferably, the mass of the TiC ceramic powder is 0.5–1% of the total mass of the NiCrAlY alloy powder and the TiC ceramic powder. Preferably, the chemical composition of the NiCrAlY alloy powder in mass percent is: Cr 15–25%, Al 5–15%, Y 0.1–1%, and the remainder is Ni35 and unavoidable impurities. BE2025 / 7052 3 Preferably, the atmosphere comprises a nitrogen atmosphere or an argon atmosphere. Preferably, parameters of high-speed laser cladding include: a laser power of 2000–6000W, a scan speed of 2000–6000mm / min, a spot diameter of 1–3mm, a powder feed rate of 510–40g / min and a scan distance of 0.5–0.7mm.Preferably, the parameters of high-speed laser cladding include: a laser power of 5000–5500 W, a scan speed of 3000 mm / min, a spot diameter of 3 mm, a powder feed rate of 30 g / min, and a scan distance of 0.6 mm. 10 The present invention discloses the following technical effects. (1) Coating properties: the NiCrAlY-TiC composite coating consists of a NiCrAlY alloy phase and a dispersed TiC ceramic reinforcement phase, the NiCrAlY alloy phase offering excellent high-temperature oxidation resistance and corrosion resistance, while the TiC-15 ceramic reinforcement phase significantly improves the hardness and wear resistance of the coating. The combination of these two phases achieves a complementary and synergistic performance increase. (2) Coating quality: the rapid cooling during high-speed laser cladding significantly refines the coating structure, reduces the composition segregation and suppresses the precipitation of brittle phases.This effectively prevents the formation of cracks and achieves a dense and defect-free coating. (3) Adhesion strength: the coating and the substrate are fully metallurgically bonded, and the adhesion strength is significantly higher than with thermally sprayed coatings, effectively preventing flaking under thermal cycling. (4) Low heat input: the characteristics of high-speed processing result in low heat input and a narrow heat-affected zone, which greatly reduces deformation and performance impairment of the substrate, making it suitable for the repair and strengthening of precision components. (5) High efficiency and flexibility: the process offers high preparation efficiency, allowing for flexible coating thickness and composition. It is well suited for the surface treatment of components with complex geometries. BE2025 / 7052 4 DESCRIPTION OF THE DRAWING Fig.Figure 1 shows a schematic diagram of the microstructure (a) and a particle size distribution diagram (b) of the NiCrAlY powder used in embodiment 1; Figure 2 shows the weight gain curves of stainless steel 304 and NiCrAlY-0.5%TiC from embodiment 1 after 360 hours of corrosion in a NaCl:Na₂SO₄ molten salt solution (50 wt.%:50 wt.%) at 650°C; and Figure 3 shows the weight gain curves of In625 and NiCrAlY-1%TiC from embodiment 2 after 360 hours of corrosion in a NaCl:Na₂SO₄-10 molten salt solution (50 wt.%:50 wt.%) at 650°C. DETAILED DESCRIPTION The present invention provides a coating with high-temperature corrosion resistance and wear resistance, and the coating with high-temperature corrosion resistance and wear resistance is a NiCrAlY-TiC composite coating, consisting of a NiCrAlY alloy phase and a dispersed TiC ceramic reinforcing phase. According to the invention, the thickness of the coating with high-temperature corrosion resistance and wear resistance is 0.2–1 mm.The coating with high-temperature corrosion resistance and wear resistance of the present invention can be applied in multiple layers as required. The present invention also provides a method for producing the aforementioned coating with high-temperature corrosion resistance and wear resistance, comprising the following steps: mixing a NiCrAlY alloy powder with a TiC ceramic powder to obtain a composite powder; and bonding the composite powder to a substrate by means of high-speed laser cladding under an inert atmosphere to form a coating on the surface of the substrate and thus obtain the coating with high-temperature corrosion resistance and wear resistance. The present invention utilizes high-speed laser cladding technology for producing coatings. High-speed laser cladding offers advantages such as a small heat-affected zone and a low dilution rate.It reduces the impact on the substrate material and simultaneously ensures the purity and performance of a coating layer, thereby enabling optimal use of the coating properties. According to the invention, the manufacturing steps of the coating with high-temperature corrosion resistance and wear resistance comprise the following: Substrate pretreatment: the substrate surface is ground and sandblasted and then ultrasonically cleaned with acetone or alcohol to remove scale and oil contamination and to increase the surface roughness. Powder preparation: Spherically gas-atomized NiCrAlY powder and TiC powder are selected and uniformly mixed in a powder mixer according to the specified ratio. 10. High-speed laser cladding: The mixed powder is introduced into a high-speed laser cladding device. A high-power semiconductor laser or fiber laser is used under an inert atmosphere.Through precise control of parameters such as laser power and scan speed, the powder and the extremely thin layer on the substrate surface are instantly melted and rapidly cooled. This creates a coating with high-temperature corrosion resistance and wear resistance (NiCrAlY-TiC composite coating). According to the invention, the mass of the TiC ceramic powder is 0.2–2% of the total mass of the NiCrAlY alloy powder and the TiC ceramic powder. According to the invention, the mass of the TiC ceramic powder is 0.5–1% of the total mass of the NiCrAlY alloy powder and the TiC ceramic powder. According to the invention, the chemical composition of the NiCrAlY alloy powder in mass percent comprises: Cr 15–25%, Al 5–15%, Y 0.1–1%, and the remainder is Ni and unavoidable impurities. According to the invention, your atmosphere comprises a nitrogen atmosphere or an argon atmosphere.According to the invention, the parameters of high-speed laser cladding include: a laser power of 2000–6000 W, a scan speed of 2000–6000 mm / min, a spot diameter of 1–3 mm, a powder feed rate of 10–40 g / min, and a scan distance of 0.5–0.7 mm. According to the invention, the parameters of high-speed laser cladding include: a laser power of 5000–5500 W, a scan speed of 3000 mm / min, a spot diameter of 3 mm, a powder feed rate of 30 g / min, and a scan distance of 0.6 mm. The present invention utilizes high-speed 35 laser cladding technology to achieve a high-performance metallurgical bond and synergistic reinforcement between NiCrAlY alloy and TiC ceramic at the micro level. This results in a composite coating system with excellent high-temperature corrosion resistance and exceptional wear resistance. The specific implementation comprises the following: First, the NiCrAlY alloy phase forms the substrate of the coating.In this process, chromium selectively oxidizes the coating surface at high temperatures, forming a dense and firmly adhering Cr₂O₃ protective film. This film effectively blocks the inward diffusion of oxygen ions and the outward diffusion of metal ions, thus forming a robust barrier against high-temperature oxidation. At the same time, the incorporation of aluminum enables the formation of a more stable Al₂O₃ film under harsher conditions or at locations where the Cr₂O₃ film is damaged, thereby achieving double oxidation protection. Trace amounts of yttrium (Y) (a rare-earth element) perform an "anchoring" function by adhering to the oxide grain boundaries and significantly improving the adhesion of the oxide film. This prevents delamination. prevented by stresses during the heat cycle processes. The synergistic effect of these three elements forms the basis for the coating's resistance to high-temperature corrosion.Furthermore, the nano- or micrometer-sized TiC ceramic particles introduced by the TiC ceramic phase are uniformly dispersed in the NiCrAlY alloy 20 as a reinforcing second phase during a high-speed laser cladding process. These TiC particles, with their high hardness and high melting point, play two key roles when the coating is subjected to friction and wear: First, they act as load-bearing elements and bear the majority of the load at the contact point between the workpiece and the coating, thereby protecting the relatively softer alloy substrate from direct plow wear. Second, they inhibit plastic deformation 25 by acting as anchor points, thus preventing the movement of dislocations within the alloy substrate. This improves the macroscopic hardness of the coating. and significantly improves their resistance to plastic deformation, thus considerably reducing adhesion and abrasive wear.Finally, high-speed laser cladding achieves the following effects: 30 First, refinement of the microstructure, whereby the rapid solidification significantly refines the grain structure and precipitation phases of the alloy and improves the strength and toughness of the coating. Second, suppression of detrimental phases, since the extremely rapid cooling rate inhibits the precipitation of brittle intermetallic compounds such as Cr-rich σ-phases, thereby preventing embrittlement of the coating 35 and reducing the tendency to crack. Third, creation of ideal interfaces, the high energy density generated by the laser ensures a limited interfacial reaction between TiC particles and the alloy melt and forms a metallurgical interface with high strength and stability.This ensures that the load is effectively transferred from the substrate to the reinforcing phase, thereby fully exploiting the reinforcing effect of TiC and simultaneously preventing particle detachment5 due to insufficient interfacial adhesion. The present invention achieves a coating material with excellent high-temperature corrosion resistance and wear resistance by synergistically combining three factors: the intrinsic oxidation resistance of the NiCrAlY alloy, the dispersion strengthening effect of the TiC ceramic phase and the ideal microstructure and10 the toughness-enhancing interfaces generated by the high-speed laser cladding technology. Various embodiments of the present invention are described in detail, which are not to be regarded as limitations of the present invention, but rather as more detailed descriptions of certain aspects, features and embodiments of the present invention.It is to be understood that the terms described in the present invention serve only to describe specific embodiments and are not used to limit the present invention. Furthermore, the value ranges specified in the present invention are to be understood as the specific disclosure of each intermediate value between the upper and lower limits of this range. Each smaller range between each specified value or range of statements and each other specified value or intermediate value within the range is also contained in the present invention. The upper and lower limits of these smaller ranges can be included or excluded from the range independently of each other. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as they are generally understood by experts in the field of the present invention.While the present invention describes only preferred methods and materials, any method and material similar or equivalent to those described herein may also be used in carrying out or testing the present invention. Documents mentioned in this description are incorporated by reference to disclose and describe methods and / or materials that refer to the aforementioned documents. In the event of a conflict with any documents incorporated herein, the contents of this specification shall prevail. BE2025 / 7052 8 Various modifications and variations can be made to the specific embodiment of the present invention without departing from the scope or spirit of the present disclosure, which is obvious to persons skilled in the art. Other embodiments obtained from the description of the present invention are also obvious to persons skilled in the art. The 5 descriptions and embodiments of the present invention are only examples.As used herein, “including”, “comprise”, “exhibit”, “contain”, and the like are all open-ended terms, i.e., meaning “including” but not “limited to”. It should be noted that all aspects of the present invention not described here in detail represent common practices within the field and are not of central importance to the invention. Unless otherwise stated, all raw materials used in the following embodiments are commercially available products. The origin of these commercially available products has no influence on the technical effect of the present invention. The chemical composition of the commercially available gas-atomized NiCrAlY master alloy powder used is, in mass percent: Cr 15–25%, Al 5–15%, Y 0.1–1%, the remainder consisting of Ni and unavoidable impurities. 20 Embodiment 1 (1) Commercially available rolled stainless steel 304L is used as the substrate material.Commercially available, gas-atomized NiCrAlY master alloy powder and TiC ceramic powder serve as raw materials for the coatings by high-speed laser cladding (HSLC). The microstructure and particle size distribution of the commercially available, gas-atomized NiCrAlY master alloy powder are shown in Fig. 1. Fig. 1 shows the microstructure (a) and particle size distribution (b) of the NiCrAlY powder used in embodiment 1. (2) The pretreatment before HSL comprises: grinding and sandblasting of the surface of the stainless steel substrate 304L, followed by ultrasonic cleaning with acetone or alcohol to remove scale and oil contaminants and to increase surface roughness; vacuum drying of NiCrAlY alloy powder at 120°C for 4 hours to remove adsorbed moisture; addition of TiC ceramic powder (0.5% of the total mass of NiCrAlY alloy powder and TiC ceramic powder) to the NiCrAlY-35 alloy powder and mixing by ball mills.BE2025 / 7052 9 (3) The mixed powder is fed into the high-speed laser cladding device. Under an argon atmosphere, a high-power semiconductor laser or fiber laser is used, with the power setting precisely controlled to 5000 W, a scan speed of 3000 mm / min, a spot diameter of 3 mm, a powder feed rate of 30 g / min, and a scan distance of 0.6 mm. The 5 composite powder is conveyed to the cladding head, where the high-power laser beam simultaneously melts it with the thin layer on the substrate surface and causes it to solidify more rapidly to form the coating (NiCrAlY-0.5% TiC). Fig. 2 shows the weight gain curves of stainless steel 304 and NiCrAlY-0.5%TiC from embodiment 1 after 360 hours of corrosion in a NaCl:Na₂SO₄ molten salt solution 10 (50 wt.%:50 wt.%) at 650°C. The test results show a wear rate of 0.375 × 10⁻³ mm³ N⁻¹ m⁻¹ for stainless steel 304L and 0.038 × 10⁻³ mm³ N⁻¹ m⁻¹ for NiCrAlY-0.5%TiC after 360 hours of corrosion in a 50 wt.% NaCl + 50 wt.% NaCl solution.-%K₂SO₄ molten salt solution at 650°C shows a corrosion weight increase of 4.56 mg / cm², while the latter shows 0.22 mg / cm² (as shown in Fig. 2). Embodiment 2 (1) Commercially available rolled In625 is used as the substrate material. Commercially available gas-atomized NiCrAlY master alloy powder and TiC ceramic powder serve as raw materials for the coatings by high-speed laser cladding (HSLC). The microstructure and particle size distribution of the commercially available gas-atomized NiCrAlY master alloy powder are shown in Fig. 1. (2) The pretreatment before HSC includes: grinding and sandblasting of the In625-25 substrate surface, followed by ultrasonic cleaning with acetone or alcohol to remove scale and oil impurities and to increase surface roughness; vacuum drying of NiCrAlY alloy powder at 120°C for 4 hours to remove adsorbed moisture.Addition of TiC ceramic powder (1% of the total mass of NiCrAlY alloy powder and TiC ceramic powder) to the NiCrAlY alloy powder and 30 mixing agents in ball mills. (3) The mixed powder is fed into the high-speed laser cladding device. Under an argon atmosphere, a high-power semiconductor or fiber laser is used, with the power setting precisely regulated to 5500 W, a scan speed of 3000 mm / min, a spot diameter of 3 mm, a powder feed rate of 30 g / min, and a scan distance of 0.6 mm. The BE2025 / 7052 10 composite powder is conveyed to the cladding head, where the high-power laser beam simultaneously melts the thin layer on the substrate surface and causes it to solidify more rapidly to form the coating (NiCrAlY-1%TiC). Fig. 3 shows the weight gain curves of In625 and NiCrAlY-1%TiC from embodiment 2 after 360 hours of corrosion in a NaCl:Na₂SO₄ melting salt solution 5 (50 wt.%: 50 wt.%) at 650°C.The test results show a wear rate of 0.052 × 10⁻³ mm³ N⁻¹ m⁻¹ for In625 and 0.031 × 10⁻³ mm³ N⁻¹ m⁻¹ for NiCrAlY-0.5% TiC. After 360 hours of corrosion in a 50 wt% NaCl + 50 wt% K₂SO₄ molten salt solution at 650°C, the former shows a corrosion weight increase of 2.18 mg / cm², while the latter shows 0.43 mg / cm² (as in the above).

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