Iron-aluminum alloy coating, preparation method thereof and alloy structure

Abstract

The invention provides an iron-aluminum alloy coating, a preparation method thereof and an alloy structure, and the iron-aluminum alloy coating comprises the following components in percentage by mass: 58-72% of FeAl, 12-18% of Ni, 6-12% of Cr, 2-8% of Ti, 1-5% of Si, 1-5% of NH4Cl, 0.1-0.3% of rare earth element and the balance of Al. A compact oxide or intermetallic compound film layer can be formed, and corrosion of a metal base material is effectively prevented. On the basis, the reasonable iron-aluminum alloy is adopted, so that the brittleness of the coating is prevented from being too high, the coating keeps certain toughness, and the wear resistance of the coating is further enhanced. The interface structure between the coating and the matrix can be optimized, the binding force between the coating and the matrix is enhanced, the coating is prevented from peeling or cracking in the using process, and the service life of the coating is prolonged. The aluminum alloy coating can be applied to thermal power plant boilers, the overall performance of the boilers is effectively improved, and the service life is effectively prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of alloy coating manufacturing, and specifically relates to an iron-aluminum alloy coating and a preparation method thereof, and an alloy structure. Background Art

[0002] At present, the inner wall and the surface of the boiler or some of the pipelines involved in the thermal power plant are prone to oxidation, wear and erosion in high temperature environments, especially when they are washed by flue gas, coal ash and flames. Such oxidation, wear and erosion will destroy the structure of the boiler or pipeline wall, or make the boiler or pipeline wall thinner. The wear amount of the boiler or some of the pipelines involved in the thermal power plant may be affected by many factors. Due to the oxidation, corrosion or wear of the inner wall of the boiler and the surface of the pipeline, serious accidents such as leakage and burst may occur.

[0003] As an improvement, in order to improve the oxidation resistance and corrosion resistance of the inner wall and pipeline of the boiler, a coating is generally applied on the surface of the inner wall and pipeline of the boiler. In this way, the service life of the inner wall and pipeline of the boiler can be improved to a certain extent, and the safety factor can be improved. For example, the iron-aluminum alloy currently used is the main raw material, combined with other raw materials to form an aluminide coating. This type of aluminide coating can form an oxide layer on the inner wall and pipeline surface of the boiler, which can effectively isolate the corrosion of the substrate by the external environment, enhance the corrosion resistance of the boiler wall to a certain extent, and thus extend the service life of the boiler. And the aluminide coating has good bonding strength with the boiler wall, which helps the coating to remain stable during the operation of the boiler, and is not easy to peel off or crack, thereby ensuring the long-term effectiveness of the coating. However, in order to improve the oxidation resistance and corrosion resistance of this type of aluminide coating, too much iron-aluminum alloy may be added. In this way, the excessive iron-aluminum alloy content may cause the coating to be too hard, thereby increasing the brittleness of the coating, making it easier to crack or peel off when it is impacted or vibrated, and this type of aluminide coating mainly considers the optimization of oxidation resistance and corrosion resistance, and the wear resistance needs to be further improved. Summary of the invention

[0004] The purpose of the present invention is to provide an iron-aluminum alloy coating and a preparation method and alloy structure thereof, so as to solve the problems in the current prior art that such aluminide coatings are highly brittle, easily crack or peel off when subjected to impact or vibration, and the wear resistance needs to be further improved.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] The invention provides an iron-aluminum alloy coating, which comprises, by mass percentage, FeAl: 58-72%, Ni: 12-18%, Cr: 6-12%, Ti: 2-8%, Si: 1-5, NH 4Cl: 1-5%, rare earth elements: 0.1-0.3%, and the rest is Al.

[0007] In some embodiments, the iron-aluminum alloy coating comprises: FeAl: 58-68%, Ni: 12-18%, Cr: 6-12, Ti: 2-8%, Si: 1-5, NH 4 Cl: 1-5%, rare earth elements: 0.1-0.3%, and the rest is Al.

[0008] In some embodiments, the rare earth element includes Ce, and in the iron-aluminum alloy coating, Ce is 0.1-0.3% by mass.

[0009] Furthermore, the iron-aluminum alloy coating includes: FeAl: 62%, Ni: 14%, Cr: 10%, Ti: 4%, Si: 2%, NH 4 Cl: 3%, rare earth elements: 0.2%, and the rest is Al.

[0010] In some embodiments, the iron-aluminum alloy coating has a Fe—Al phase, a Ni—Al phase, and a Cr—Al phase.

[0011] The present invention also provides a method for preparing an iron-aluminum alloy coating, comprising the following steps:

[0012] S1. Weigh each component according to the mass percentage, and mechanically mix the components to obtain a mixed powder;

[0013] S2, pre-treating the substrate surface;

[0014] S3, placing the pretreated substrate in a sintering container, and laying a penetrant in the sintering container; using the mixed powder to embed the substrate to form a container to be sintered;

[0015] S4. Place the container to be sintered in a high-temperature furnace for sintering, and form an iron-aluminum alloy coating on the surface of the substrate after cooling.

[0016] In some embodiments, in S2, the pretreatment of the substrate surface includes: cleaning, grinding, degreasing, and drying.

[0017] In some embodiments, in S3, the infiltrant includes a filler, an activator, boron powder or silicon powder.

[0018] In some embodiments, in S4, the sintering parameters are controlled as follows: the temperature is controlled to be 980-1150° C., and the time is controlled to be 20-40 min.

[0019] The present invention also provides an alloy structure, comprising an alloy structure substrate and the iron-aluminum alloy coating coated on the alloy structure substrate.

[0020] Compared with the prior art, the iron-aluminum alloy coating and its preparation method and alloy structure of the present invention have at least the following beneficial effects:

[0021] The invention provides an iron-aluminum alloy coating, which comprises, by mass percentage, FeAl: 58-72%, Ni: 12-18%, Cr: 6-12%, Ti: 2-8%, Si: 1-5, NH 4 Cl: 1-5%, rare earth elements: 0.1-0.3%, and the rest is Al. Based on the above, the present invention can ensure the corrosion resistance of the coating by adopting elements such as Ni, Cr, and Ti. In particular, in harsh environments such as humidity, high temperature, and high salt, a dense oxide or intermetallic compound film can be formed to effectively prevent corrosion of the metal substrate. On this basis, the present invention can avoid the excessive brittleness of the coating by adopting a reasonable content of iron-aluminum alloy, so that it maintains a certain toughness. Since the iron-aluminum alloy has good hardness and wear resistance, and the FeAl, Ni, Cr and other elements in the coating can further enhance the wear resistance of the coating, so that the coating can maintain stability for a long time when subjected to friction and wear. In addition, the use of NH4Cl and rare earth elements in the coating of the present invention can optimize the interface structure between the coating and the substrate, enhance the bonding force between the coating and the substrate, help prevent the coating from peeling off or cracking during use, and increase the service life of the coating. The iron-aluminum alloy coating of the present invention can be applied to the surface of the boiler wall or pipeline wall of a thermal power plant. After coating, it can effectively improve the mechanical properties and service life of the boiler as a whole, and has better practical significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings in the specification are used to provide further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0023] Figure 1 It is a schematic diagram of the organizational morphology of the iron-aluminum alloy coating prepared in Example 1 of the iron-aluminum alloy coating and its preparation method and alloy structure of the present invention;

[0024] Figure 2 It is a comparative schematic diagram of an iron-aluminum alloy coating and a preparation method thereof, and a wear resistance test of the iron-aluminum alloy coating in an alloy structure of the present invention;

[0025] Figure 3 The present invention is a schematic diagram of the comparison of the surface morphology of an iron-aluminum alloy coating and a preparation method thereof, and an alloy structure of the iron-aluminum alloy coating of the present invention before and after the coating friction test in a wear resistance test. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0027] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0028] Herein, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0029] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0030] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0031] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0032] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0033] How to ensure that the iron-aluminum alloy coating has better oxidation resistance and corrosion resistance, avoid the high brittleness of the coating, and effectively improve the wear resistance of the coating.

[0034] Based on this, the present invention provides an iron-aluminum alloy coating, which comprises, by mass percentage, FeAl: 58-72%, Ni: 12-18%, Cr: 6-12, Ti: 2-8%, Si: 1-5, NH 4 Cl: 1-5%, rare earth elements: 0.1-0.3%, and the rest is Al.

[0035] The iron-aluminum alloy coating of the present invention adopts an iron-aluminum alloy with a reasonable ratio. Based on the excellent high-temperature oxidation resistance and high hardness of the iron-aluminum alloy, the iron-aluminum alloy provides a main skeleton and strength for the coating of the present invention, ensures the stability and wear resistance of the coating in a high-temperature environment, and significantly improves the high-temperature resistance of the coating, increases the hardness and wear resistance of the coating, and prolongs the service life of the coating, so that the coating improves the overall performance of the substrate after being applied to the substrate.

[0036] In some embodiments, the present invention further optimizes the content of FeAl, so as to further avoid the problem of high brittleness of the coating while ensuring that the iron-aluminum alloy coating has better oxidation resistance and corrosion resistance, and can effectively improve the wear resistance of the coating. The details are as follows:

[0037] Preferably, the iron-aluminum alloy coating comprises: FeAl: 58-68%, Ni: 12-18%, Cr: 6-12%, Ti: 2-8%, Si: 1-5, NH 4 Cl: 1-5%, rare earth elements: 0.1-0.3%, and the rest is Al.

[0038] Further preferably, the iron-aluminum alloy coating comprises: FeAl: 62%, Ni: 14%, Cr: 10%, Ti: 4%, Si: 2%, NH 4 Cl: 3%, rare earth elements: 0.2%, and the rest is Al.

[0039] Furthermore, the iron-aluminum alloy coating includes: FeAl: 62%, Ni: 14%, Cr: 10%, Ti: 4%, Si: 2%, NH 4 Cl: 3%, rare earth elements: 0.2%, and the rest is Al.

[0040] The iron-aluminum alloy coating of the present invention, based on the iron-aluminum alloy, cooperates with the characteristics of other elements, and optimizes the coating performance through combination and proportioning. Specifically, the present invention can significantly improve the corrosion resistance of the coating by using nickel in a certain content. If the substrate is used in an acidic and alkaline environment, the coating of the present invention can improve the corrosion resistance of the substrate, and nickel can enhance the bonding force between the coating and the substrate, improve the adhesion of the coating, and to a certain extent avoid the problem of the coating falling off after being vibrated.

[0041] The present invention can further improve the hardness and wear resistance of the coating by adopting reasonable chromium, enhance the oxidation resistance of the coating, and extend the service life of the coating. The Ti element can improve the thermal stability and mechanical properties of the coating, improve the surface quality of the coating, enhance the thermal stability of the coating, keep the performance stable in a high temperature environment, improve the surface quality of the coating, and improve the appearance and performance of the coating.

[0042] The present invention enhances the hardness and wear resistance of the coating by adding a certain amount of silicon, and simultaneously improves the oxidation resistance and corrosion resistance of the coating, so as to enhance the durability of the coating and extend the service life of the coating.

[0043] The present invention can promote the chemical reaction between elements in the process of coating formation, optimize the coating structure, and improve the coating performance by using NH4Cl and a trace amount of rare earth element Ce. The chemical reaction in the process of coating formation is promoted to make the coating structure more uniform and dense. The bonding force between the coating and the substrate is improved, and the adhesion of the coating is enhanced.

[0044] The iron-aluminum alloy coating of the present invention has Fe-Al phase, Ni-Al phase and Cr-Al phase. 3 Al-based alloys can form dense Al 2 O 3 Oxide film, so it has certain anti-oxidation properties. Fe-Al phase may exist in various forms, such as FeAl, Fe3Al, etc. Ni-Al phase may exist in the form of NiAl, Ni3Al, etc. These phases can form a dense oxide film at high temperature to prevent further oxidation of the substrate and play an anti-oxidation role. Cr-Al phase may include CrAl, Cr2Al3, etc., which can enhance the mechanical properties and chemical stability of the coating.

[0045] The present invention also provides a method for preparing an iron-aluminum alloy coating, comprising the following steps:

[0046] S1. Weigh each component according to the mass percentage, and mechanically mix the components to obtain a mixed powder;

[0047] S2, pre-treating the substrate surface;

[0048] S3, placing the pretreated substrate into a sintering container, and laying a penetrant in the sintering container; using the mixed powder to embed the substrate to form a container to be sintered;

[0049] S4. Place the container to be sintered in a high-temperature furnace for sintering, and form an iron-aluminum alloy coating on the surface of the substrate after cooling.

[0050] In some embodiments, in S2, the pretreatment of the substrate surface includes: cleaning, grinding, degreasing, and drying. The present invention performs necessary pretreatments such as cleaning, rust removal, and grinding on the substrate surface to remove oil stains, oxides, and other impurities on the substrate surface, thereby ensuring that the coating can be relatively firmly attached to the substrate surface in subsequent preparation.

[0051] In some embodiments, in S3, the penetrant includes a filler, an activator, boron powder or silicon powder. The present invention prepares a suitable penetrant, such as a filler, an activator, boron powder or silicon powder, etc., according to the characteristics of the coating raw material and the required reaction conditions, which can be used to promote the penetration and reaction of the coating raw material on the substrate surface and promote the formation of the coating on the substrate surface.

[0052] In some embodiments, in S4, the sintering parameters are controlled as follows: the temperature is controlled to be 980-1150°C, and the time is controlled to be 20-40 minutes. The present invention can reasonably control the sintering temperature and time so that during the high temperature treatment process, the coating raw materials can penetrate and react on the substrate surface to form the desired iron-aluminum alloy coating.

[0053] In addition, the present invention also provides an alloy structure, including an alloy substrate and an iron-aluminum alloy coating coated on the alloy substrate. In a specific embodiment, such as in a thermal power plant boiler or pipeline, by using the iron-aluminum alloy coating of the present invention to apply to the thermal power plant boiler, the problem of high brittleness of the coating can be avoided while ensuring that the boiler has better oxidation resistance and corrosion resistance, and the wear resistance of the coating can be effectively improved, which helps to increase the service life of the overall structure.

[0054] The following is a detailed description of an iron-aluminum alloy coating and a preparation method thereof, and an alloy structure of the present invention through specific embodiments:

[0055] Example 1

[0056] Weigh FeAl: 62%, Ni: 14%, Cr: 10%, Ti: 4%, Si: 2%, NH 4 Cl: 3%, rare earth elements: 0.2%, and the rest is Al. The weighed components are placed in a ball mill and mixed by ball milling to obtain a mixed powder;

[0057] Select Super304H as the base of the coating, select the appropriate size of Super304H according to the quality of the mixed powder, clean, polish, degrease the surface of Super304H, and then dry it;

[0058] The above-mentioned Super304H is placed in a sintering container, and aluminum oxide is laid in the sintering container; the mixed powder is used to embed the Super304H, and then the sintering container is placed in a high-temperature furnace for sintering, the temperature is controlled at 1120°C, sintering for 30 minutes, and then naturally cooled to remove surface impurities, and an iron-aluminum alloy coating is formed on the surface of the Super304H. The present invention conducts a wear resistance test on the overall structure obtained in Example 1. Figure 1 As shown, it is a morphology picture of the iron-aluminum alloy coating formed on the surface of Super304H prepared in this embodiment. It can be seen that a uniform and dense iron-aluminum alloy coating is formed on the surface of Super304H.

[0059] Example 2

[0060] Weigh FeAl: 58%, Ni: 16%, Cr: 10%, Ti: 6%, Si: 2%, NH 4 Cl: 3%, rare earth elements: 0.2%, and the rest is Al. The weighed components are placed in a ball mill and ball-milled to obtain a mixed powder;

[0061] Select Super304H as the base of the coating, select the appropriate size of Super304H according to the quality of the mixed powder, clean, polish, degrease the surface of Super304H, and then dry it;

[0062] The above-mentioned Super304H is placed in a sintering container, and alumina is laid in the sintering container; the Super304H is embedded with mixed powder, and then the sintering container is placed in a high-temperature furnace for sintering, the temperature is controlled at 1050°C, sintering for 30 minutes, and then naturally cooled to remove surface impurities, and an iron-aluminum alloy coating is formed on the surface of the Super304H.

[0063] Example 3

[0064] Weigh FeAl: 72%, Ni: 10%, Cr: 6%, Ti: 2%, Si: 2%, NH 4 Cl: 3%, rare earth elements: 0.2%, and the rest is Al. The weighed components are placed in a ball mill and ball-milled to obtain a mixed powder;

[0065] Select Super304H as the base of the coating, select the appropriate size of Super304H according to the quality of the mixed powder, clean, polish, degrease the surface of Super304H, and then dry it;

[0066] The above-mentioned Super304H is placed in a sintering container, and alumina is laid in the sintering container; the Super304H is embedded with mixed powder, and then the sintering container is placed in a high-temperature furnace for sintering, the temperature is controlled at 1050°C, sintering for 30 minutes, and then naturally cooled to remove surface impurities, and an iron-aluminum alloy coating is formed on the surface of the Super304H.

[0067] Example 4

[0068] Weigh FeAl: 65%, Ni: 12%, Cr: 10%, Ti: 4%, Si: 2%, NH 4 Cl: 2%, rare earth elements: 0.2%, and the rest is Al. The weighed components are placed in a ball mill and mixed by ball milling to obtain a mixed powder;

[0069] Select Super304H as the base of the coating, select the appropriate size of Super304H according to the quality of the mixed powder, clean, polish, degrease the surface of Super304H, and then dry it;

[0070] The above-mentioned Super304H is placed in a sintering container, and alumina is laid in the sintering container; the Super304H is embedded with mixed powder, and then the sintering container is placed in a high-temperature furnace for sintering, the temperature is controlled at 1100°C, sintering for 25 minutes, and then naturally cooled to remove surface impurities, and an iron-aluminum alloy coating is formed on the surface of the Super304H.

[0071] Example 5

[0072] Weigh FeAl: 60%, Ni: 18%, Cr: 12%, Ti: 4%, Si: 2%, NH 4 Cl: 3%, rare earth elements: 0.2%, and the rest is Al. The weighed components are placed in a ball mill and ball-milled to obtain a mixed powder;

[0073] Select Super304H as the base of the coating, select the appropriate size of Super304H according to the quality of the mixed powder, clean, polish, degrease the surface of Super304H, and then dry it;

[0074] The above-mentioned Super304H is placed in a sintering container, and alumina is laid in the sintering container; the Super304H is embedded with mixed powder, and then the sintering container is placed in a high-temperature furnace for sintering, the temperature is controlled at 1150°C, sintering for 20 minutes, and then naturally cooled to remove surface impurities, and an iron-aluminum alloy coating is formed on the surface of the Super304H.

[0075] The wear resistance test of the iron-aluminum alloy coating in Example 1 of the present invention is carried out as follows, and the specific test and data are as follows:

[0076] Following the national standard GB / T12444-2006 "Metallic Material Wear Test Method", the wear resistance of two structures of Super304H without iron-aluminum alloy coating (hereinafter referred to as Super304H) and Super304H with iron-aluminum alloy coating (hereinafter referred to as Super304H coating) was tested. Under the same test conditions, Figure 2 As shown in the figure, the friction and wear of the Super304H coating is reduced by about 39% and the friction coefficient is reduced by about 13%. Figure 3 As shown, it is a schematic diagram of the surface morphology of the Super304H coating (b and d in the figure) and the Super304H base material (a and c in the figure) obtained in Example 1 after the friction test. It can be seen that the surface structure of the Super304H coating is relatively complete and has good wear resistance. Therefore, the alloy structure using the iron-aluminum alloy coating of the present invention has good wear resistance.

[0077] In summary, the present invention provides an iron-aluminum alloy coating and a preparation method and alloy structure thereof. Based on the excellent high-temperature oxidation resistance of the iron-aluminum alloy itself, a dense oxide film can be formed under a high-temperature environment to effectively prevent further oxidation of the substrate. The present invention significantly improves the hardness and wear resistance of the coating through a reasonable composition ratio, and the iron-aluminum alloy cooperates with Cr, Ti and Si, so that it can resist external wear and extend its service life. In addition, the present invention significantly improves the corrosion resistance of the coating by adopting a reasonable Ni element, so that it can maintain stable performance in acidic and alkaline environments. The iron-aluminum alloy coating of the present invention has good bonding force with the substrate, and is not easy to fall off when subjected to external forces such as vibration. The preparation method provided by the present invention includes the steps of mechanical mixing, pretreatment, embedding sintering, etc. The preparation method is simple to operate and has wide applicability. The iron-aluminum alloy coating of the present invention can be widely used in various occasions that require high-temperature oxidation resistance, corrosion resistance and wear resistance, such as boilers and pipelines in thermal power plants, and can effectively improve the overall performance and service life of boilers and pipelines in thermal power plants.

[0078] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as shown in the specification and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. An iron-aluminum alloy coating, characterized in that: In terms of mass percentage, the iron-aluminum alloy coating comprises: FeAl: 58-72%, Ni: 12-18%, Cr: 6-12, Ti: 2-8%, Si: 1-5, NH4Cl: 1-5%, rare earth elements: 0.1-0.3%, and the rest is Al.

2. The iron-aluminum alloy coating according to claim 1, characterized in that: The iron-aluminum alloy coating comprises: FeAl: 58-68%, Ni: 12-18%, Cr: 6-12, Ti: 2-8%, Si: 1-5, NH4Cl: 1-5%, rare earth elements: 0.1-0.3%, and the rest is Al.

3. The iron-aluminum alloy coating according to claim 1, characterized in that: The rare earth elements include Ce. In terms of mass percentage, in the iron-aluminum alloy coating, Ce is 0.1-0.3%.

4. The iron-aluminum alloy coating according to claim 3, characterized in that: The iron-aluminum alloy coating comprises: FeAl: 62%, Ni: 14%, Cr: 10%, Ti: 4%, Si: 2%, NH4Cl: 3%, rare earth elements: 0.2%, and the rest is Al.

5. The iron-aluminum alloy coating according to claim 1, characterized in that: The iron-aluminum alloy coating layer has a Fe-Al phase, a Ni-Al phase and a Cr-Al phase.

6. The method for preparing the iron-aluminum alloy coating according to any one of claims 1 to 5, characterized in that: The steps include: S1. Weigh each component according to the mass percentage, and mechanically mix the components to obtain a mixed powder; S2, pre-treating the substrate surface; S3, placing the pretreated substrate in a sintering container, and laying a penetrant in the sintering container; using the mixed powder to embed the substrate to form a container to be sintered; S4. Place the container to be sintered in a high-temperature furnace for sintering, and form an iron-aluminum alloy coating on the surface of the substrate after cooling.

7. The method for preparing an iron-aluminum alloy coating according to claim 6, characterized in that: In S2, the pretreatment of the substrate surface includes: cleaning, grinding, degreasing, and drying.

8. The method for preparing an iron-aluminum alloy coating according to claim 6, characterized in that: In S3, the infiltrant includes a filler, an activator, boron powder or silicon powder.

9. The method for preparing an iron-aluminum alloy coating according to claim 6, characterized in that: In the step S4, the sintering parameters are controlled as follows: the temperature is controlled at 980-1150° C., and the sintering time is controlled at 20-40 min.

10. An alloy structure, characterized in that: The invention comprises an alloy structural substrate and an iron-aluminum alloy coating as claimed in any one of claims 1 to 5 coated on the alloy structural substrate.

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