Laser cladding metal silicide ceramic coating as well as preparation method and application thereof

Abstract

The invention relates to the technical field of metal material surface modification, in particular to a laser cladding metal silicide ceramic coating and a preparation method and application thereof. According to the preparation method, a double-gradient high-entropy alloy coating design of a transition layer and a functional layer is adopted, Fe-Cr-Ni-Co-Si high-entropy alloy with low Si content and Fe-Cr-Ni-Co-Si high-entropy alloy with high Si content are sequentially prepared on the surface of a steel substrate through a laser cladding technology to serve as the transition layer and the functional layer correspondingly, and then conversion of a eutectic phase to a uniform (Fe-Cr-Ni-Co) 3Si metal silicide phase is achieved through heat treatment. The transition layer can relieve interface stress and prevent the coating from cracking and stripping; the functional layer takes (Fe-Cr-Ni-Co) 3Si as a main phase, has high wear resistance, corrosion resistance and high-temperature stability, and has no cracking risk caused by Ti / Al doping. The prepared coating adapts to the severe working condition of a high-temperature blade of a high-temperature furnace, the service life of the blade can be remarkably prolonged, and the coating has wide industrial application prospects.

Description

Technical Field

[0001] This invention relates to the field of surface modification technology for metal materials, specifically to a laser cladding metal silicide ceramic coating, its preparation method, and its application. Background Technology

[0002] High-temperature (blast furnace gas residual pressure turbine power generation unit) blades are the core components of the high-temperature furnace system. They are used for a long time in high-temperature (usually 400~800℃), dusty, and corrosive furnace gas environments, and face severe friction and wear and media corrosion, which leads to blade surface failure, shortened service life, frequent shutdowns for replacement, affecting production efficiency and increasing operation and maintenance costs.

[0003] High-entropy alloys exhibit excellent corrosion resistance and high-temperature stability due to the synergistic effect of multiple principal components. However, these high-entropy alloys have low hardness (HV≤300) and insufficient wear resistance. Under high-temperature friction conditions, they are prone to adhesive wear and abrasive wear, which cannot meet the long-term wear resistance requirements of high-temperature blades.

[0004] In existing technologies, to improve the wear resistance of Fe-Cr-Ni-Co high-entropy alloys, elements such as Ti and Al are typically used to dope them, forming intermetallic compound reinforcing phases to improve hardness and wear resistance. However, the atomic radii of Ti and Al differ significantly from those of the matrix elements, and the intermetallic compound phases are highly brittle. This makes it difficult to control cracking during coating preparation, severely affecting the coating's bonding strength and service life, thus limiting its widespread application in critical components such as high-temperature blades.

[0005] Metal silicides (such as) High-Si alloys (Fe-Cr-Ni-Co-Si, etc.) possess high hardness (HV≥800), excellent high-temperature wear resistance, and high-temperature oxidation resistance. Furthermore, Si exhibits good atomic radius matching with Fe, Cr, Ni, and Co, making it less prone to significant lattice distortion after doping. However, when directly preparing high-Si content Fe-Cr-Ni-Co-Si high-entropy alloy coatings on steel substrates, the significant difference in thermal expansion coefficients between the coating and the substrate easily leads to large interfacial stresses, causing coating cracking and peeling. Simultaneously, the formation of a eutectic phase during laser cladding of high-Si content coatings is crucial to preventing cracking, as grain boundaries can buffer some stress. Therefore, achieving a strong bond between the coating and the substrate and the formation of a uniform and stable metal silicide phase through reasonable coating design and process control, while avoiding cracking defects, is key to solving the wear and crack resistance problem of high-temperature blades. Summary of the Invention

[0006] To address the technical problems existing in the prior art, the present invention aims to provide a laser-clad metal silicide ceramic coating to solve the aforementioned technical problems. The present invention aims to overcome the shortcomings of insufficient wear resistance and easy cracking during Ti and Al doping reinforcement of existing Fe-Cr-Ni-Co-Si high-entropy alloy coatings, and provides a method for preparing laser-clad metal silicide ceramic coatings and high-temperature blades. Through gradient high-entropy alloy coating design and heat treatment process, a strong bond between the coating and the substrate is achieved, obtaining a crack-free, uniform (Fe-Cr-Ni-Co)3Si phase functional layer that balances high wear resistance, corrosion resistance, high-temperature stability, and crack resistance, making it suitable for the harsh operating conditions of high-temperature blades.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution.

[0008] According to a first aspect of the present invention, a laser-clad metal silicide ceramic coating is provided, comprising a transition layer and a functional layer; Both the transition layer and the functional layer are Fe-Cr-Ni-Co-Si high-entropy alloy coatings (the transition layer is a low-Si content Fe-Cr-Ni-Co-Si high-entropy alloy, and the functional layer is a high-Si content Fe-Cr-Ni-Co-Si high-entropy alloy). In the transition layer, the atomic percentage of Si is 5-10%; In the functional layer, the atomic percentage of Si is 23%-27%.

[0009] The transition layer and the functional layer form a gradient structure.

[0010] In some implementations, the atomic percentage of Si is 5-8%.

[0011] One side of the transition layer is connected to the substrate surface, and the other side of the transition layer away from the substrate is connected to the functional layer.

[0012] The transition layer contains a small amount of metal silicides and Fe-Cr-Ni-Co-Si solid solution phases, and is free from cracking defects. The transition layer is used to relieve interfacial stress and achieve metallurgical bonding with the substrate and functional layers, thus avoiding cracking.

[0013] The phase of the functional layer is a uniform (Fe-Cr-Ni-Co)3Si metal silicide phase, free from cracking defects. In some embodiments, the atomic percentage of Si in the functional layer is 25%.

[0014] In some embodiments, in the transition layer, the atomic percentage of Si is 5-10%, with the remainder being Fe, Cr, Ni, and Co, and the atomic ratio of Fe, Cr, Ni, and Co is 1:1:1:1; in the functional layer, the atomic percentage of Si is 23%-27%, with the remainder being Fe, Cr, Ni, and Co, and the atomic ratio of Fe, Cr, Ni, and Co is 1:1:1:1.

[0015] In some embodiments, the atomic percentage of Si in the transition layer is 5-8%.

[0016] In some embodiments, the thickness of the transition layer is 0.3~0.8 mm; the thickness of the functional layer is 1.0~2.0 mm.

[0017] The functional layer of the laser-clad metal silicide ceramic coating provided by this invention has a hardness ≥ HV600 and a wear rate ≤ 5 × 10⁻⁶ at high temperatures of 400~800℃. It exhibits superior corrosion resistance compared to undoped Si Fe-Cr-Ni-Co high-entropy alloy coatings. According to a second aspect of the present invention, a method for preparing a laser-clad metal silicide ceramic coating is provided, comprising the following steps: High-entropy alloy powders required for the transition layer and functional layer are prepared separately. The transition layer is prepared on the substrate surface by laser cladding (the transition layer with a thickness of 0.3~0.8 mm is formed after cladding, the transition layer forms a metallurgical bond with the substrate, a small amount of metal silicide is generated inside, and there is no cracking). Then, the functional layer is prepared on the surface of the transition layer by laser cladding (the functional layer containing (Fe-Cr-Ni-Co)3Si grains and grain boundary eutectic phases and without cracking, with a thickness of 1.0~2.0 mm) to obtain the clad substrate. The clad substrate is heated for heat treatment (to transform the eutectic phase in the functional layer into the (Fe-Cr-Ni-Co)3Si phase), and then cooled to room temperature in the furnace to obtain the laser-clad metal silicide ceramic coating.

[0018] In some embodiments, the substrate undergoes pretreatment before laser cladding. This pretreatment includes grinding, degreasing, derusting, cleaning, and drying. Grinding, degreasing, and derusting aim to remove surface oxide scale, oil, and impurities. Cleaning and drying can be performed using anhydrous ethanol.

[0019] In some embodiments, the high-entropy alloy powders required for preparing the transition layer and functional layer respectively include: Add Si powder to Fe-Cr-Ni-Co quaternary alloy powder to obtain a first mixed powder. Control the atomic percentage of Si in the first mixed powder to be 5-10%. Ball mill the powder to obtain the high-entropy alloy powder required for the transition layer. Si powder is added to Fe-Cr-Ni-Co quaternary alloy powder to obtain a second mixed powder. The atomic percentage of Si in the second mixed powder is controlled to be 23%-27%. The powder is then ball-milled to obtain the high-entropy alloy powder required for the functional layer.

[0020] In some embodiments, Si powder is added to Fe-Cr-Ni-Co quaternary alloy powder to obtain a first mixed powder, and the atomic percentage of Si in the first mixed powder is controlled to be 5-8%.

[0021] In some embodiments, the atomic ratio of Fe, Cr, Ni and Co in the Fe-Cr-Ni-Co quaternary alloy powder is 1:1:1:1, and the particle size of the Fe-Cr-Ni-Co quaternary alloy powder is 53~150μm; the particle size of the Si powder is 50~100μm.

[0022] In some embodiments, the purity of the Si powder is ≥99.5%.

[0023] In some embodiments, the ball milling process is carried out at a rotation speed of 200-300 r / min for 2-4 hours. The ball milling process is performed using a planetary ball mill.

[0024] In some embodiments, the substrate is 2Cr13 stainless steel or 20G boiler steel; In some embodiments, when a transition layer is prepared on the substrate surface by laser cladding, the laser power is 1500~1800W and the laser scanning speed is 600~900mm / min; In some embodiments, when a transition layer is prepared on the substrate surface by laser cladding, the laser power is 1500~1800W and the laser scanning speed is 600~800mm / min; In some embodiments, when a transition layer is prepared on the substrate surface by laser cladding, the laser cladding spot diameter is 4 mm, the powder feed rate is 12 g / min, the protective gas is argon, and the flow rate is 10 L / min.

[0025] In some embodiments, when the functional layer is prepared on the surface of the transition layer by laser cladding, the laser power is 2000~2400W and the laser scanning speed is 600~900mm / min.

[0026] In some embodiments, when the functional layer is prepared on the surface of the transition layer by laser cladding, the laser power is 2000~2400W and the laser scanning speed is 600~800mm / min.

[0027] In some embodiments, when the functional layer is prepared on the surface of the transition layer by laser cladding, the laser cladding spot diameter is 4 mm, the powder feed rate is 25 g / min, the protective gas is argon, and the flow rate is 10 L / min. In some embodiments, the heating rate is 5-10℃ / min, the heat treatment temperature is 850-950℃, and the heat treatment time is 2-4h. After heat treatment, the phase of the functional layer is a uniform (Fe-Cr-Ni-Co)3Si metal silicide phase without obvious cracking defects.

[0028] In some embodiments, the heating rate is 5°C / min.

[0029] According to a third aspect of the present invention, the present invention provides the application of laser-clad metal silicide ceramic coatings in the fabrication of high-temperature furnace blades. When the laser-clad metal silicide ceramic coating is applied to high-temperature furnace blades, the coating is metallurgically bonded to the substrate, the functional layer hardness is ≥HV800, and the wear rate at high temperatures of 400~800℃ is ≤5×10⁻⁶. It exhibits superior corrosion resistance compared to undoped Si Fe-Cr-Ni-Co high-entropy alloy coatings, and is free from cracking defects caused by Ti and Al doping.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The coating provided by the present invention adopts the Fe-Cr-Ni-Co-Si high-entropy alloy system. By replacing the traditional Ti and Al doping with Si doping, the atomic radius matching between Si and the matrix element is good, avoiding the internal stress concentration caused by lattice distortion, and solving the cracking problem of Ti and Al doped coatings from the root. At the same time, the metal silicide phase formed by Si has both high hardness and certain toughness, ensuring the integrity of the coating structure.

[0031] (2) The coating provided by the present invention adopts a gradient design of “low Si transition layer + high Si functional layer”. The low Si content in the transition layer forms a small amount of metal silicide and high entropy alloy solid solution phase coexisting structure, which not only ensures the metallurgical bonding strength with the steel substrate, but also buffers the difference in thermal expansion coefficient between the functional layer and the substrate, significantly reduces the interface stress, and further avoids coating cracking and peeling, thus solving the technical problem of poor bonding between high Si content coating and substrate.

[0032] (3) In the coating provided by the present invention, the functional layer achieves the transformation of the eutectic phase to the uniform (Fe-Cr-Ni-Co)3Si phase by precisely controlling the atomic ratio of (Fe-Cr-Ni-Co) to Si, so that the atomic percentage of Si is 23%-27%, and the eutectic phase is transformed into the uniform (Fe-Cr-Ni-Co)3Si phase by heat treatment. The (Fe-Cr-Ni-Co)3Si metal silicide has high hardness and excellent high temperature wear resistance, which increases the hardness of the coating to HV≥600, significantly improving the wear resistance defects of Fe-Cr-Ni-Co-Si high entropy alloy.

[0033] (4) The coating provided by the present invention retains the excellent corrosion resistance of Fe-Cr-Ni-Co-Si high-entropy alloy. At the same time, the addition of Si enhances the coating’s resistance to high-temperature oxidation, so that the coating can maintain stable performance under complex working conditions of high temperature, corrosion and wear, adapt to the service requirements of high-temperature blades, and extend the service life of blades by 3 to 5 times.

[0034] (5) The preparation process provided by the present invention adopts laser cladding technology, which has the advantages of strong bonding between the coating and the substrate, good molding quality and high efficiency. The heat treatment process is simple and easy to control, and is suitable for industrial mass production. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a microstructure diagram (SEM image) of the transition layer obtained in step 3 of Embodiment 1 of this application. Figure 2 This is the XRD characterization diagram of the functional layer obtained in step 4 of Embodiment 1 of this application; Figure 3 This is a microstructure (SEM) image of the functional layer after heat treatment in step 5 of Embodiment 1 of this application. Figure 4 This is the XRD characterization diagram of the functional layer after heat treatment in step 5 of Embodiment 1 of this application; Figure 5 A photograph of a laser-clad metal silicide ceramic coating on a high-temperature blade, provided in Embodiment 1 of this application. Detailed Implementation

[0037] To better understand the technical solution of the present invention, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1 A method for preparing a laser-clad metal silicide ceramic coating includes the following steps: 1. Substrate pretreatment: 2Cr13 stainless steel was selected as the substrate for high-temperature blades. The substrate surface was sanded with sandpaper, ultrasonically degreased with acetone for 15 minutes, and cleaned with anhydrous ethanol after rust removal. It was then dried for later use.

[0039] 2. Powder preparation: Transition layer powder: Fe-Cr-Ni-Co quaternary alloy powder (atomic ratio 1:1:1:1, particle size 53~150μm) is mixed with Si powder (purity 99.6%, particle size 50~80μm) to form Fe-Cr-Ni-Co-Si high-entropy alloy powder. The atomic fraction of Si is controlled to be 10%. The mixture is ball-milled in a planetary ball mill for 3 hours at a speed of 250 r / min to obtain the transition layer mixed powder. Functional layer powder: Fe-Cr-Ni-Co quaternary alloy powder is mixed with Si powder to form Fe-Cr-Ni-Co-Si high-entropy alloy powder. The atomic ratio of (Fe-Cr-Ni-Co) to Si is controlled at 3:1 (the atomic fraction of Si is 25%). The powder is mixed evenly with the same ball milling parameters to obtain functional layer mixed powder. 3. Laser cladding of the transition layer: Laser power 1800W, scanning speed 600mm / min, spot diameter 4mm, powder feed rate 15g / min, argon flow rate 10L / min, forming a 0.5mm thick transition layer after cladding. (Example:...) Figure 1 As shown in the figure, SEM characterization revealed that the transition layer was metallurgically bonded to the substrate, with a small amount of (Fe-Cr-Ni-Co)3Si metal silicides present inside, and no cracking was observed.

[0040] 4. Functional layer laser cladding: Laser power 2400W, scanning speed 600mm / min, spot diameter 4mm, powder feed rate 25g / min, argon flow rate 10L / min, preheated to 300℃, forming a 1.5mm thick functional layer after cladding. (Example: ...) Figure 2 As shown, XRD characterization revealed that the functional layer contains (Fe-Cr-Ni-Co)3Si grains and Fe-Cr-Ni-Co-Si eutectic phase, with no obvious cracking defects.

[0041] 5. Heat treatment: The heating rate is 5℃ / min, the temperature is raised to 900℃, held for 3 hours, and then cooled to room temperature in the furnace to obtain the laser clad metal silicide ceramic coating. Figure 3 This is a microstructure (SEM) image of the functional layer after heat treatment in step 5 of Embodiment 1 of this application, as shown below. Figure 3 As shown in the figure, SEM characterization revealed that the heat-treated functional layer (Fe-Cr-Ni-Co) 3Si grains were dense and closely arranged, with incomplete elimination of grain boundaries and no cracking. Figure 4 As shown, XRD characterization after heat treatment revealed that the Fe-Cr-Ni-Co-Si eutectic phase was transformed into the (Fe-Cr-Ni-Co)3Si phase. Figure 5 This is a photograph of a laser-clad metal silicide ceramic coating on a high-temperature blade, as provided in Embodiment 1 of this application. Figure 5 As shown, the blade cladding layer has a good appearance, no cracks, and is qualified.

[0042] Performance testing The coating prepared in Example 1 was subjected to the following performance tests, and the performance tests of the coatings in the other examples were also conducted in accordance with Example 1. Specifically, the hardness test was performed according to GB / T4340.1-2024; the high-temperature abrasion resistance test was performed according to GB / T 43853-2024; and the corrosion resistance test was performed according to ISO 8407:2018.

[0043] Hardness: Using a Vickers hardness tester, with a load of 500g and a holding time of 15s, the average hardness of the functional layer is >HV600, which is much higher than HV280 of the Fe-Cr-Ni-Co high-entropy alloy without Si doping. High-temperature wear resistance: A ball-and-disc friction and wear test was conducted at 500℃ with a load of 50N, a sliding speed of 0.5m / s, and a wear time of 1h. The coating wear rate was 9.23×10⁻⁶. It is only 1 / 5 of that of the undoped Si high-entropy alloy coating; Corrosion resistance: It exhibits good corrosion resistance at 500℃, which is superior to that of undoped Si high-entropy alloy coating (the preparation method of this coating can be referred to the transition layer preparation in Example 1, the only difference being that only Fe-Cr-Ni-Co quaternary alloy powder is used for preparation, with an atomic ratio of 25%:25%:25%:25%, without adding Si powder), and has excellent corrosion resistance. Example 2 This embodiment is basically the same as Embodiment 1, except that: the atomic fraction of Si in the transition layer is 5%, the atomic ratio of (Fe-Cr-Ni-Co) to Si in the functional layer is 3:1 (the atomic percentage of Si is 25%), the heat treatment temperature is 900℃, the holding time is 4 hours, and the coating is cooled in the furnace to obtain the laser-clad metal silicide ceramic coating. Test results show that the functional layer coating has a strength > HV600, and the wear rate at 500℃ is 1.9 × 10⁻⁶. It has good corrosion resistance and meets the requirements for high-temperature blades.

[0044] Example 3 This embodiment is basically the same as Embodiment 1, except that: the atomic fraction of Si in the transition layer is 7%, the atomic ratio of (Fe-Cr-Ni-Co) to Si in the functional layer is 3:1 (the atomic percentage of Si is 25%), the heat treatment temperature is 900℃, the holding time is 4 hours, and the coating is cooled in the furnace to obtain the laser-clad metal silicide ceramic coating. Test results show that the functional layer coating has a strength > HV600, and the wear rate at 500℃ is 2.3 × 10⁻⁶. It has good corrosion resistance and meets the requirements for high-temperature blades.

[0045] Example 4 This embodiment is basically the same as Embodiment 1, except that: the atomic fraction of Si in the transition layer is 10%, the atomic ratio of (Fe-Cr-Ni-Co) to Si in the functional layer is 3:1 (the atomic percentage of Si is 25%), the heat treatment temperature is 900℃, the holding time is 4 hours, and the coating is cooled in the furnace to obtain the laser-clad metal silicide ceramic coating. Test results show that the coating functional layer has a strength > HV600, and the wear rate at 500℃ is 1.9 × 10⁻⁶. It has good corrosion resistance and meets the requirements for high-temperature blades.

[0046] Example 5 This embodiment is basically the same as Embodiment 1, except that the atomic percentage of Si in the transition layer is 10%, the atomic percentage of Si in the functional layer is 23%, the heat treatment temperature is 900℃, the holding time is 4 hours, and the material is cooled in the furnace to obtain the laser-clad metal silicide ceramic coating. Test results show that the coating functional layer has a strength > HV550, and the wear rate at 500℃ is 5.4 × 10⁻⁶. It has good corrosion resistance and meets the requirements for high-temperature blades.

[0047] Example 6 This embodiment is basically the same as Embodiment 1, except that: the atomic fraction of Si in the transition layer is 10%, the atomic ratio of the functional layer (Fe-Cr-Ni-Co) to Si is 3:1 (the atomic percentage of Si is 25%), the heat treatment temperature is 850℃, the holding time is 4 hours, and it is cooled in the furnace. Test results show that the coating functional layer has a strength > HV600, and the wear rate at 500℃ is 1.5 × 10⁻⁶. It has good corrosion resistance and meets the requirements for high-temperature blades.

[0048] Example 7 This embodiment is basically the same as Embodiment 1, except that: the atomic fraction of Si in the transition layer is 10%, the atomic ratio of the functional layer (Fe-Cr-Ni-Co) to Si is 3:1 (the atomic percentage of Si is 25%), the heat treatment temperature is 870℃, the holding time is 4 hours, and it is cooled in the furnace. Test results show that the coating functional layer has a strength > HV600, and the wear rate at 500℃ is 1.4 × 10⁻⁶. It has good corrosion resistance and meets the requirements for high-temperature blades.

[0049] Examples 8-18 were carried out with reference to Example 1 and were basically the same as Example 1, except that the parameters during laser cladding were changed, as shown in Table 1 below.

[0050] Table 1 As shown in Table 1, the transition layer has a low content of metal-ceramic phase, so the coating can be manufactured with a low laser power. However, if the laser scanning speed is increased, the transition layer may develop poor bonding, cracks, or holes. The functional layer has a high content of metal-ceramic phase, so the laser power needs to be increased while the speed is reduced to increase the heat input and keep the workpiece at a certain temperature in order to manufacture a crack-free coating.

[0051] The above descriptions are merely some embodiments of the present invention. Those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A laser-clad metal silicide ceramic coating, characterized in that, Includes a transition layer and a functional layer; Both the transition layer and the functional layer are Fe-Cr-Ni-Co-Si high-entropy alloy coatings; In the transition layer, the atomic percentage of Si is 5-10%; In the functional layer, the atomic percentage of Si is 23%-27%.

2. The laser-clad metal silicide ceramic coating according to claim 1, characterized in that, In the transition layer, the atomic percentage of Si is 5-10%, with the remainder being Fe, Cr, Ni, and Co, and the atomic ratio of Fe, Cr, Ni, and Co is 1:1:1:1; in the functional layer, the atomic percentage of Si is 23%-27%, with the remainder being Fe, Cr, Ni, and Co, and the atomic ratio of Fe, Cr, Ni, and Co is 1:1:1:

1.

3. The laser-clad metal silicide ceramic coating according to claim 1, characterized in that, The thickness of the transition layer is 0.3~0.8mm; the thickness of the functional layer is 1.0~2.0mm.

4. A method for preparing a laser-clad metal silicide ceramic coating according to any one of claims 1-3, characterized in that, Includes the following steps: High-entropy alloy powders required for the transition layer and functional layer are prepared separately. The transition layer is prepared on the surface of the substrate by laser cladding, and then the functional layer is prepared on the surface of the transition layer by laser cladding to obtain the clad substrate. The clad substrate is then heated for heat treatment to obtain the laser-clad metal silicide ceramic coating.

5. The preparation method according to claim 4, characterized in that, The high-entropy alloy powders required for preparing the transition layer and functional layer respectively include: Add Si powder to Fe-Cr-Ni-Co quaternary alloy powder to obtain a first mixed powder. Control the atomic percentage of Si in the first mixed powder to be 5-10%. Ball mill the powder to obtain the high-entropy alloy powder required for the transition layer. Si powder is added to Fe-Cr-Ni-Co quaternary alloy powder to obtain a second mixed powder. The atomic percentage of Si in the second mixed powder is controlled to be 23%-27%. The powder is then ball-milled to obtain the high-entropy alloy powder required for the functional layer.

6. The preparation method according to claim 5, characterized in that, The Fe-Cr-Ni-Co quaternary alloy powder has an atomic ratio of Fe, Cr, Ni and Co of 1:1:1:1, and the particle size of the Fe-Cr-Ni-Co quaternary alloy powder is 53~150μm; the particle size of the Si powder is 50~100μm.

7. The preparation method according to claim 5, characterized in that, The ball milling process is carried out at a rotation speed of 200-300 r / min and for a duration of 2-4 h.

8. The preparation method according to claim 4, characterized in that, The substrate is 2Cr13 stainless steel or 20G boiler steel; when the transition layer is prepared on the substrate surface by laser cladding, the laser power is 1500~1800W and the laser scanning speed is 600~900mm / min; when the functional layer is prepared on the surface of the transition layer by laser cladding, the laser power is 2000~2400W and the laser scanning speed is 600~900mm / min.

9. The preparation method according to claim 4, characterized in that, The heating rate is 5-10℃ / min, the heat treatment temperature is 850-950℃, and the heat treatment time is 2-4h.

10. The application of the laser cladding metal silicide ceramic coating according to any one of claims 1-3 in the preparation of high-temperature furnace blades.

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