Wear-resistant anti-oxidation coating as well as preparation method and application thereof

Abstract

The invention provides a wear-resistant anti-oxidation coating and a preparation method and application thereof.The preparation method of the wear-resistant anti-oxidation coating comprises the following steps that S1, aluminum powder, silicon powder, aluminum oxide powder, titanium powder, zirconium powder, hafnium powder and vanadium powder are mixed, and a metal mixture is obtained; s2, the metal mixture is adopted to embed a matrix, sintering treatment is carried out under the inert atmosphere, and an initial coating is formed on the surface of the matrix; and S3, nitriding treatment is conducted on the initial coating formed on the base body, and the wear-resisting and oxidation-resisting coating is formed on the base body. The wear-resistant anti-oxidation coating disclosed by the invention has very high hardness and very good wear resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of material surface coatings, and in particular relates to a wear-resistant and oxidation-resistant coating and a preparation method and application thereof. Background Art

[0002] The boiler tube in the generator set is an important part of the boiler, and its performance and quality directly affect the safe and economical operation of the generator set. The boiler tube is in a high temperature environment for a long time. The high temperature will accelerate the oxidation reaction of the metal material and form oxide scale. The oxide scale will not only increase the thermal resistance and reduce the heat transfer efficiency, but also may peel off due to thermal expansion and contraction, blocking the pipeline or corroding other parts. Therefore, a coating is usually applied on the inner wall of the boiler tube to improve the oxidation resistance of the boiler tube.

[0003] Among them, the aluminum silicon coating can form a continuous, uniform and dense aluminum oxide and silicon oxide protective film on the surface under high temperature oxidation environment, which enables the coating to maintain its shape and performance at high temperature. However, the wear resistance of this coating is insufficient. Boiler tubes operate under high temperature and high pressure environment and are easily eroded by particles such as coal ash and flue gas, resulting in coating wear. If the wear resistance of the coating is insufficient, it will be difficult to resist such erosion, thus shortening the service life of the coating. Summary of the invention

[0004] In order to solve the above problems of the prior art, the present invention provides a wear-resistant and anti-oxidation coating and a preparation method and application thereof. The method of the present invention can improve the hardness and wear resistance of the coating.

[0005] The present invention is achieved through the following technical solutions: A method for preparing a wear-resistant and oxidation-resistant coating comprises the following steps: S1, mixing aluminum powder, silicon powder, alumina powder, titanium powder, zirconium powder, hafnium powder and vanadium powder to obtain a metal mixture; S2, embedding a substrate with the metal mixture, and performing a sintering treatment in an inert atmosphere to form an initial coating on the surface of the substrate; S3, performing nitriding treatment on the initial coating formed on the substrate to form a wear-resistant and oxidation-resistant coating on the substrate.

[0006] Preferably, in terms of mass fractions, the metal mixture in S1 includes: 65-80 parts of aluminum powder, 5-15 parts of silicon powder, 10-20 parts of alumina powder, 2-10 parts of titanium powder, 3-8 parts of zirconium powder, 1-5 parts of hafnium powder, and 5-10 parts of vanadium powder.

[0007] Preferably, S1 specifically includes: Aluminum powder, silicon powder, alumina powder, titanium powder, zirconium powder, hafnium powder and vanadium powder are taken, stirred and mixed, ball-milled and dried in sequence to obtain a metal mixture.

[0008] Preferably, in S2, the sintering temperature is 900-1100° C., and the sintering time is 30-90 min.

[0009] Preferably, in S2, the inert atmosphere is an argon atmosphere.

[0010] Preferably, in S3, the nitriding treatment is performed by gas nitriding.

[0011] Preferably, S3 is specifically: placing the substrate formed with the initial coating in a nitriding device, introducing ammonia into the nitriding device, and when the air in the nitriding device is emptied, continuing to introduce ammonia and heating to 470~500℃ for 2~4 hours, and then heating to 530~550℃ for 2~4 hours to obtain a wear-resistant and antioxidant coating.

[0012] Preferably, the flow rate of ammonia is 1-1.5 L / min.

[0013] The present invention also provides a wear-resistant and oxidation-resistant coating obtained by the preparation method as described above.

[0014] The present invention also provides application of the wear-resistant and oxidation-resistant coating in boiler tubes of thermal power units.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The preparation method of the wear-resistant and oxidation-resistant coating of the present invention is to form an initial coating composed of aluminum, silicon, aluminum oxide, titanium, zirconium, hafnium and vanadium on the surface of the substrate by embedding a metal mixture and sintering at high temperature. When in service, aluminum and silicon will undergo oxidation reaction with oxygen to generate SiO2 protective film and Al2O3 protective film. These protective films can effectively prevent oxygen from further contacting the metal substrate inside the coating, so that the coating has oxidation resistance. In the subsequent nitriding process, the nitrogen infiltrated into the initial coating can react with the metal in the initial coating, especially titanium, zirconium, hafnium and vanadium to form metal nitride, thereby greatly improving the hardness and wear resistance of the coating. In addition, silicon can also react with nitrogen to form silicon nitride (Si3N4). Si3N4 has good oxidation resistance and can effectively block the penetration of oxygen, thereby protecting the substrate material from oxidation corrosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1The microhardness distribution (along the coating depth direction) from the wear-resistant and oxidation-resistant coating to the Super304H substrate on the Super304H sample in Example 1 of the present invention; Figure 2 This is a comparison diagram of the hardness change curve of the wear-resistant and oxidation-resistant coating in Example 1 of the present invention after one year of service in a furnace; Figure 3 is the wear amount of the wear-resistant and oxidation-resistant coating in Example 1 of the present invention and the initial coating in Comparative Example 1; Figure 4 It is the friction coefficient of the wear-resistant and oxidation-resistant coating in Example 1 of the present invention and the initial coating in Comparative Example 1. DETAILED DESCRIPTION

[0018] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0019] It should be noted that the process equipment or devices not specifically specified in the following embodiments are all conventional equipment or devices in the art.

[0020] It should be noted that the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the present invention without substantially changing the technical content.

[0021] The method for preparing the wear-resistant and oxidation-resistant coating of the present invention comprises the following steps: S1, mixing aluminum powder, silicon powder, alumina powder, titanium powder, zirconium powder, hafnium powder and vanadium powder to obtain a metal mixture; S2, embedding a substrate with the metal mixture, and performing a sintering treatment in an inert atmosphere to form an initial coating on the surface of the substrate; S3, performing nitriding treatment on the initial coating formed on the substrate to form a wear-resistant and oxidation-resistant coating on the substrate.

[0022] Calculated by weight, the metal mixture of the present invention includes: 65-80 parts of aluminum powder, 5-15 parts of silicon powder, 10-20 parts of aluminum oxide powder, 2-10 parts of titanium powder, 3-8 parts of zirconium powder, 1-5 parts of hafnium powder, and 5-10 parts of vanadium powder.

[0023] In the preparation method of the wear-resistant and oxidation-resistant coating of the present invention, the substrate is first embedded with a metal mixture and sintered at high temperature, so that the metal elements form an initial coating composed of aluminum, silicon, aluminum oxide, titanium, zirconium, hafnium, and vanadium on the surface of the substrate. When in service, aluminum and silicon will undergo oxidation reaction with oxygen to generate SiO2 protective film and Al2O3 protective film. These protective films can effectively prevent oxygen from further contacting the metal substrate inside the coating, so that the coating has oxidation resistance. In the subsequent nitriding process, the nitrogen infiltrated into the initial coating can react with the metal in the initial coating, especially titanium, zirconium, hafnium, and vanadium to form metal nitrides, thereby greatly improving the hardness and wear resistance of the coating. In addition, silicon can also react with nitrogen to form silicon nitride (Si3N4), which has good oxidation resistance and can effectively block the penetration of oxygen, thereby protecting the substrate material from oxidation corrosion.

[0024] In a specific embodiment of the present invention, S1 specifically includes: Aluminum powder, silicon powder, alumina powder, titanium powder, zirconium powder, hafnium powder and vanadium powder are sequentially stirred and mixed, ball-milled and mixed, and dried to obtain a metal mixture.

[0025] In some specific embodiments of the present invention, the sintering temperature in S2 is 900-1100° C., the sintering time is 30-90 min, and the inert atmosphere used is argon atmosphere.

[0026] In a specific embodiment of the present invention, the nitriding treatment adopts a gas nitriding method, and of course, salt bath nitriding and ion nitriding can also be selected according to actual needs.

[0027] During the gas nitriding process, the uniformity of the nitriding temperature and atmosphere is good, which is conducive to obtaining a uniform nitriding layer. This is of great significance for improving the overall performance and service life of the workpiece.

[0028] Specifically, the nitriding process of the present invention is: The substrate with the initial coating is placed in a nitriding device, and ammonia is introduced into the nitriding device at a rate of 1-1.5 L / min. When the air in the nitriding device is exhausted, ammonia is continued to be introduced and the temperature is raised to 470-500 °C for 2-4 h, and then raised to 530-550 °C for 2-4 h to obtain the final wear-resistant and oxidation-resistant coating.

[0029] The present invention adopts a two-stage nitriding process, which can reduce the deformation of the workpiece to a certain extent by controlling the temperature and ammonia decomposition rate during the nitriding process. This is particularly important for parts that need to maintain high-precision size and shape.

[0030] Example 1 The method for preparing the wear-resistant and oxidation-resistant coating of the present invention comprises the following steps: (1) Weigh the raw materials: 70 parts of aluminum powder, 10 parts of silicon powder, 10 parts of alumina powder, 5 parts of titanium powder, 5 parts of zirconium powder, 3 parts of hafnium powder, and 8 parts of vanadium powder; (2) The weighed raw materials are stirred and mixed for 12 hours, then ball-milled for 6 hours, and dried at 80° C. for 12 hours to obtain a metal mixture for use; (3) Rinse the surface of the austenitic steel Super304H sample with a high-pressure water gun and then clean it with alcohol; (4) The Super304H sample was embedded with the above metal mixture, heated to 1000°C and sintered for 15 min in an argon atmosphere, and then cooled to room temperature to form an initial coating on the surface of the Super304H sample; (5) The Super304H sample with the initial coating was placed in a nitriding device, and ammonia was introduced into the nitriding device at a rate of 1 L / min. After the air in the nitriding device was exhausted, ammonia was continued to be introduced and the temperature was raised to 500 °C and kept for 3 h, and then raised to 530 °C and kept for 3 h to obtain the final wear-resistant and oxidation-resistant coating.

[0031] Example 2 The method for preparing the wear-resistant and oxidation-resistant coating of the present invention comprises the following steps: (1) Weigh the raw materials: 65 parts of aluminum powder, 5 parts of silicon powder, 20 parts of alumina powder, 8 parts of titanium powder, 3 parts of zirconium powder, 3 parts of hafnium powder, and 5 parts of vanadium powder; (2) The weighed raw materials are stirred and mixed for 12 hours, then ball-milled for 6 hours, and dried at 80° C. for 12 hours to obtain a metal mixture for use; (3) Rinse the surface of the austenitic steel Super304H sample with a high-pressure water gun and then clean it with alcohol; (4) The Super304H sample was embedded with the above metal mixture, heated to 1000°C and sintered for 60 min in an argon atmosphere, and then cooled to room temperature to form an initial coating on the surface of the Super304H sample; (5) The Super304H sample with the initial coating was placed in a nitriding device, and ammonia was introduced into the nitriding device at a rate of 1 L / min. After the air in the nitriding device was exhausted, ammonia was continued to be introduced and the temperature was raised to 500 °C and kept for 3 h, and then raised to 530 °C and kept for 3 h to obtain the final wear-resistant and oxidation-resistant coating.

[0032] Example 3 The method for preparing the wear-resistant and oxidation-resistant coating of the present invention comprises the following steps: (1) Weigh the raw materials: 80 parts of aluminum powder, 10 parts of silicon powder, 10 parts of alumina powder, 5 parts of titanium powder, 8 parts of zirconium powder, 1 part of hafnium powder, and 5 parts of vanadium powder; (2) The weighed raw materials are stirred and mixed for 12 hours, then ball-milled for 6 hours, and dried at 80° C. for 12 hours to obtain a metal mixture for use; (3) Rinse the surface of the austenitic steel Super304H sample with a high-pressure water gun and then clean it with alcohol; (4) The Super304H sample was embedded with the above metal mixture, heated to 1000°C and sintered for 15 min in an argon atmosphere, and then cooled to room temperature to form an initial coating on the surface of the Super304H sample; (5) The Super304H sample with the initial coating was placed in a nitriding device, and ammonia was introduced into the nitriding device at a rate of 1 L / min. After the air in the nitriding device was exhausted, ammonia was continued to be introduced and the temperature was raised to 500 °C and kept for 3 h, and then raised to 530 °C and kept for 3 h to obtain the final wear-resistant and oxidation-resistant coating.

[0033] Example 4 The method for preparing the wear-resistant and oxidation-resistant coating of the present invention comprises the following steps: (1) Weigh the raw materials: 70 parts of aluminum powder, 15 parts of silicon powder, 15 parts of alumina powder, 10 parts of titanium powder, 5 parts of zirconium powder, 5 parts of hafnium powder, and 10 parts of vanadium powder; (2) The weighed raw materials are stirred and mixed for 12 hours, then ball-milled for 6 hours, and dried at 80° C. for 12 hours to obtain a metal mixture for use; (3) Rinse the surface of the austenitic steel Super304H sample with a high-pressure water gun and then clean it with alcohol; (4) The Super304H sample was embedded with the above metal mixture, heated to 1000°C and sintered for 15 min in an argon atmosphere, and then cooled to room temperature to form an initial coating on the surface of the Super304H sample; (5) The Super304H sample with the initial coating was placed in a nitriding device, and ammonia was introduced into the nitriding device at a rate of 1 L / min. After the air in the nitriding device was exhausted, ammonia was continued to be introduced and the temperature was raised to 500 °C and kept for 3 h, and then raised to 530 °C and kept for 3 h to obtain the final wear-resistant and oxidation-resistant coating.

[0034] Example 5 The method for preparing the wear-resistant and oxidation-resistant coating of the present invention comprises the following steps: (1) Weigh the raw materials: 70 parts of aluminum powder, 10 parts of silicon powder, 10 parts of alumina powder, 5 parts of titanium powder, 5 parts of zirconium powder, 3 parts of hafnium powder, and 8 parts of vanadium powder; (2) The weighed raw materials are stirred and mixed for 12 hours, then ball-milled for 6 hours, and dried at 80° C. for 12 hours to obtain a metal mixture for use; (3) Rinse the surface of the austenitic steel Super304H sample with a high-pressure water gun and then clean it with alcohol; (4) The Super304H sample was embedded with the above metal mixture, heated to 900°C and sintered for 90 min in an argon atmosphere, and then cooled to room temperature to form an initial coating on the surface of the Super304H sample; (5) The Super304H sample with the initial coating was placed in a nitriding device, and ammonia was introduced into the nitriding device at a rate of 1 L / min. After the air in the nitriding device was exhausted, ammonia was continued to be introduced and the temperature was raised to 500 °C and kept for 3 h, and then raised to 530 °C and kept for 3 h to obtain the final wear-resistant and oxidation-resistant coating.

[0035] Example 6 The method for preparing the wear-resistant and oxidation-resistant coating of the present invention comprises the following steps: (1) Weigh the raw materials: 70 parts of aluminum powder, 10 parts of silicon powder, 10 parts of alumina powder, 5 parts of titanium powder, 5 parts of zirconium powder, 3 parts of hafnium powder, and 8 parts of vanadium powder; (2) The weighed raw materials are stirred and mixed for 12 hours, then ball-milled for 6 hours, and dried at 80° C. for 12 hours to obtain a metal mixture for use; (3) Rinse the surface of the austenitic steel Super304H sample with a high-pressure water gun and then clean it with alcohol; (4) The Super304H sample was embedded with the above metal mixture, heated to 1100°C and sintered for 30 min in an argon atmosphere, and then cooled to room temperature to form an initial coating on the surface of the Super304H sample; (5) The Super304H sample with the initial coating was placed in a nitriding device, and ammonia was introduced into the nitriding device at a rate of 1 L / min. After the air in the nitriding device was exhausted, ammonia was continued to be introduced and the temperature was raised to 500 °C and kept for 3 h, and then raised to 530 °C and kept for 3 h to obtain the final wear-resistant and oxidation-resistant coating.

[0036] Example 7 The method for preparing the wear-resistant and oxidation-resistant coating of the present invention comprises the following steps: (1) Weigh the raw materials: 70 parts of aluminum powder, 10 parts of silicon powder, 10 parts of alumina powder, 5 parts of titanium powder, 5 parts of zirconium powder, 3 parts of hafnium powder, and 8 parts of vanadium powder; (2) The weighed raw materials are stirred and mixed for 12 hours, then ball-milled for 6 hours, and dried at 80° C. for 12 hours to obtain a metal mixture for use; (3) Rinse the surface of the austenitic steel Super304H sample with a high-pressure water gun and then clean it with alcohol; (4) The Super304H sample was embedded with the above metal mixture, heated to 950°C and sintered for 45 min in an argon atmosphere, and then cooled to room temperature to form an initial coating on the surface of the Super304H sample; (5) The Super304H sample with the initial coating was placed in a nitriding device, and ammonia was introduced into the nitriding device at a rate of 1 L / min. After the air in the nitriding device was exhausted, ammonia was continued to be introduced and the temperature was raised to 500 °C and kept for 3 h, and then raised to 530 °C and kept for 3 h to obtain the final wear-resistant and oxidation-resistant coating.

[0037] Example 8 The method for preparing the wear-resistant and oxidation-resistant coating of the present invention comprises the following steps: (1) Weigh the raw materials: 70 parts of aluminum powder, 10 parts of silicon powder, 10 parts of alumina powder, 5 parts of titanium powder, 5 parts of zirconium powder, 3 parts of hafnium powder, and 8 parts of vanadium powder; (2) The weighed raw materials are stirred and mixed for 12 hours, then ball-milled for 6 hours, and dried at 80° C. for 12 hours to obtain a metal mixture for use; (3) Rinse the surface of the austenitic steel Super304H sample with a high-pressure water gun and then clean it with alcohol; (4) The Super304H sample was embedded with the above metal mixture, heated to 1000°C and sintered for 60 min in an argon atmosphere, and then cooled to room temperature to form an initial coating on the surface of the Super304H sample; (5) The Super304H sample with the initial coating was placed in a nitriding device, and ammonia was introduced into the nitriding device at a rate of 1 L / min. After the air in the nitriding device was exhausted, ammonia was continued to be introduced and the temperature was raised to 470 °C and kept for 4 h, and then raised to 550 °C and kept for 2 h to obtain the final wear-resistant and oxidation-resistant coating.

[0038] Example 9 The method for preparing the wear-resistant and oxidation-resistant coating of the present invention comprises the following steps: (1) Weigh the raw materials: 70 parts of aluminum powder, 10 parts of silicon powder, 10 parts of alumina powder, 5 parts of titanium powder, 5 parts of zirconium powder, 3 parts of hafnium powder, and 8 parts of vanadium powder; (2) The weighed raw materials are stirred and mixed for 12 hours, then ball-milled for 6 hours, and dried at 80° C. for 12 hours to obtain a metal mixture for use; (3) Rinse the surface of the austenitic steel Super304H sample with a high-pressure water gun and then clean it with alcohol; (4) The Super304H sample was embedded with the above metal mixture, heated to 1000°C and sintered for 60 min in an argon atmosphere, and then cooled to room temperature to form an initial coating on the surface of the Super304H sample; (5) The Super304H sample with the initial coating was placed in a nitriding device, and ammonia was introduced into the nitriding device at a rate of 1.5 L / min. After the air in the nitriding device was exhausted, ammonia was continued to be introduced and the temperature was raised to 490°C and kept for 2 h, and then raised to 530°C and kept for 4 h to obtain the final wear-resistant and oxidation-resistant coating.

[0039] Comparative Example 1 The coating preparation method of this comparative example comprises the following steps: (1) Weigh the raw materials: 70 parts of aluminum powder, 10 parts of silicon powder, 10 parts of alumina powder, 5 parts of titanium powder, 5 parts of zirconium powder, 3 parts of hafnium powder, and 8 parts of vanadium powder; (2) The weighed raw materials are stirred and mixed for 12 hours, then ball-milled for 6 hours, and dried at 80° C. for 12 hours to obtain a metal mixture for use; (3) Rinse the surface of the austenitic steel Super304H sample with a high-pressure water gun and then clean it with alcohol; (4) The Super304H sample was embedded with the above metal mixture, heated to 1000°C in an argon atmosphere and sintered for 15 min, then cooled to room temperature to form an initial coating on the surface of the Super304H sample.

[0040] The present invention complies with the national standard GB / T 4340-2009 "Vickers Hardness Test for Metallic Materials" and tests the change trend of the microhardness from the wear-resistant and oxidation-resistant coating on the Super304H sample in Example 1 to the Super304H substrate area. The results are as follows Figure 1 shown.

[0041] from Figure 1 It can be seen that as the coating depth increases, the hardness gradually decreases. This is because during the nitriding process, nitrogen first enters the coating surface and gradually diffuses deeper. The deeper the depth, the less nitrogen there is, that is, the nitrogen concentration is distributed in a gradient. As the depth increases, the nitrogen concentration decreases, and the metal-nitride formed is also less, so the hardness decreases accordingly.

[0042] like Figure 2As shown, the hardness change curve of the coating in Example 1 after one year of service is compared. It can be seen that the annual degradation rate of the coating hardness of the Super304H sample in Example 1 after one year of service is less than 5%, indicating that the coating prepared by the present invention has good stability.

[0043] Following the national standard GB / T 12444-2006 "Metallic Material Wear Test Method", the wear resistance of the wear-resistant and anti-oxidation coating on the Super304H sample in Example 1 and the initial coating in Comparative Example 1 were tested. Figure 3 and Figure 4 As shown, compared with comparative example 1, under the same test conditions, the wear loss of the coating in example 1 was reduced by about 26%, and the friction coefficient was reduced by about 16%. This shows that the nitriding treatment greatly improves the wear resistance of the coating.

Claims

1. A method for preparing a wear-resistant and oxidation-resistant coating, characterized in that: The following steps are involved: S1, mixing aluminum powder, silicon powder, alumina powder, titanium powder, zirconium powder, hafnium powder and vanadium powder to obtain a metal mixture; S2, embedding a substrate with the metal mixture, and performing a sintering treatment in an inert atmosphere to form an initial coating on the surface of the substrate; S3, performing nitriding treatment on the initial coating formed on the substrate to form a wear-resistant and oxidation-resistant coating on the substrate.

2. The method for preparing the wear-resistant and oxidation-resistant coating according to claim 1, characterized in that: In terms of mass percentage, the metal mixture in S1 includes: 65-80 parts of aluminum powder, 5-15 parts of silicon powder, 10-20 parts of aluminum oxide powder, 2-10 parts of titanium powder, 3-8 parts of zirconium powder, 1-5 parts of hafnium powder, and 5-10 parts of vanadium powder.

3. The method for preparing the wear-resistant and oxidation-resistant coating according to claim 1, characterized in that: S1 specifically includes: Aluminum powder, silicon powder, alumina powder, titanium powder, zirconium powder, hafnium powder and vanadium powder are taken, stirred and mixed, ball-milled and dried in sequence to obtain a metal mixture.

4. The method for preparing the wear-resistant and oxidation-resistant coating according to claim 1, characterized in that: In S2, the sintering temperature is 900~1100℃, and the sintering time is 30~90min.

5. The method for preparing the wear-resistant and oxidation-resistant coating according to claim 1, characterized in that: In S2, the inert atmosphere is an argon atmosphere.

6. The method for preparing the wear-resistant and oxidation-resistant coating according to claim 1, characterized in that: In S3, the nitriding treatment is performed by gas nitriding.

7. The method for preparing the wear-resistant and oxidation-resistant coating according to claim 1, characterized in that: S3 is specifically as follows: placing the substrate with the initial coating in a nitriding device, introducing ammonia into the nitriding device, and after the air in the nitriding device is exhausted, continuing to introduce ammonia and heating the device to 470-500 °C for 2-4 h, and then heating the device to 530-550 °C for 2-4 h to obtain a wear-resistant and oxidation-resistant coating.

8. The method for preparing the wear-resistant and oxidation-resistant coating according to claim 1, characterized in that: The flow rate of ammonia is 1~1.5 L / min.

9. A wear-resistant and oxidation-resistant coating obtained by the preparation method according to any one of claims 1 to 7.

10. Use of the wear-resistant and oxidation-resistant coating according to claim 8 in boiler tubes of thermal power units.

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