Chromium oxide-based coating and method for its production and use

Abstract

This invention discloses a chromium oxide-based coating, its preparation method, and its application. The preparation method of the chromium oxide-based coating of this invention includes the following steps: 1) dispersing ceramic particles and / or metal particles, chromium oxide particles, and a binder in water, wherein the particle size of the ceramic and metal particles is smaller than that of the chromium oxide particles, followed by spray drying to obtain composite particles; 2) thermally spraying the composite particles onto the surface of a substrate to obtain the chromium oxide-based coating. The chromium oxide-based coating of this invention possesses both high hardness and excellent toughness, exhibiting superior resistance to friction and wear, and can be used as a wear-resistant coating for the surface of metal parts, making it suitable for large-scale industrial applications.

Description

Technical Field

[0001] This invention relates to the field of thermal spraying technology, specifically to a chromium oxide-based coating, its preparation method, and its application. Background Technology

[0002] Friction and wear are among the main factors leading to the failure of various metal components in mechanical equipment across industries such as metallurgy, aerospace, machinery, petrochemicals, mining, and agricultural machinery. Therefore, reducing friction and wear on metal components plays a crucial role in the safety, reliability, and economic efficiency of mechanical equipment. Ceramic materials possess characteristics such as high hardness, high mechanical strength, good friction and wear resistance, and good chemical stability. Applying ceramic coatings to the surface of metal components using surface engineering techniques can significantly improve their wear resistance. Chromium oxide ceramics, with their advantages of high hardness, ease of processing, low coefficient of friction, high temperature resistance, wear resistance, and corrosion resistance, are suitable as surface wear-resistant coatings for mechanical components operating under special conditions.

[0003] Hardness is a key reference indicator for evaluating the wear resistance of wear-resistant coatings. The hardness of wear-resistant components must exceed the hardness of the abrasive or at least reach 80% of its hardness; otherwise, their wear resistance will inevitably be insufficient. Currently, the Vickers hardness of chromium oxide coatings prepared by plasma spraying is approximately 1100 HV. 0.3 ~1300HV 0.3 The Vickers hardness of the chromium oxide coating prepared by supersonic flame spraying is 1000 HV. 0.3 ~1200HV 0.3 Furthermore, the Vickers hardness of chromium oxide-based coatings prepared by other methods (e.g., composite chromium oxide coatings with added alumina or titanium oxide) is generally lower than 1300 HV. 0.3 .

[0004] Toughness is a key performance indicator for evaluating the resistance of wear-resistant parts to fracture and plays a positive role in mitigating micro-fatigue spalling caused by pure wear. However, chromium oxide ceramic coatings are characterized by high brittleness and high porosity. In particular, their high brittleness leads to low fracture toughness, which reduces the friction and wear resistance of chromium oxide coatings. Currently, the crack resistance of chromium oxide-based ceramic coatings is mainly improved to some extent by mixing alumina or titanium oxide with metal powders (two or more powders are directly mixed and then sprayed to obtain a two-phase or multi-phase material coating, where different types of materials usually exist in the coating in their own independent block form), but this leads to a decrease in the hardness of the coating.

[0005] The microstructure and structure of a coating are important factors affecting its hardness and fracture toughness. By designing and controlling the microstructure of the sprayed powder material, it is possible to obtain chromium oxide-based ceramic coatings with high hardness and excellent toughness, which is of great significance for improving the friction and wear resistance of wear-resistant parts.

[0006] Therefore, it is of great significance to develop a chromium oxide-based coating that combines high hardness, excellent toughness, and superior resistance to friction and wear. Summary of the Invention

[0007] The purpose of this invention is to provide a chromium oxide-based coating, its preparation method, and its application.

[0008] The technical solution adopted in this invention is:

[0009] A method for preparing a chromium oxide-based coating includes the following steps:

[0010] 1) Ceramic particles and / or metal particles, chromium oxide particles and binder are dispersed in water, with the particle size of ceramic particles and metal particles being smaller than that of chromium oxide particles, and then spray-dried to obtain composite particles.

[0011] 2) The composite particles are thermally sprayed onto the substrate surface to obtain a chromium oxide-based coating.

[0012] Preferably, the mass ratio of ceramic particles and / or metal particles and chromium oxide particles in step 1) is 1:5 to 25.

[0013] Preferably, the amount of binder used in step 1) is 8% to 12% of the total weight of ceramic particles and / or metal particles and chromium oxide particles.

[0014] Preferably, the amount of water used in step 1) is 1 to 1.5 times the total weight of the ceramic particles and / or metal particles and chromium oxide particles.

[0015] Preferably, the particle size of the ceramic particles in step 1) is 0.1 μm to 5 μm.

[0016] Preferably, the ceramic particles in step 1) are at least one of alumina ceramic particles, titanium dioxide ceramic particles, zirconia ceramic particles, and yttrium oxide-stabilized zirconia ceramic particles.

[0017] Preferably, the ceramic particles in step 1) are spherical or near-spherical in shape.

[0018] Preferably, the purity of the ceramic particles in step 1) is greater than 99%.

[0019] Preferably, the particle size of the metal particles in step 1) is 0.1 μm to 10 μm.

[0020] Preferably, the metal particles in step 1) are composed of at least one of nickel, aluminum, cobalt, and titanium.

[0021] Preferably, the metal particles in step 1) are spherical or near-spherical in shape.

[0022] Preferably, the purity of the metal particles in step 1) is greater than 99%.

[0023] Preferably, the particle size of the chromium oxide particles in step 1) is 10 μm to 50 μm.

[0024] Preferably, the purity of the chromium oxide particles in step 1) is greater than 99%.

[0025] Preferably, the mass ratio of ceramic particles and / or metal particles to chromium oxide particles in the composite particles in step 1) is 1:5 to 100.

[0026] Preferably, the adhesive in step 1) is at least one of polyvinyl alcohol, polysilazane, and polyacrylic acid.

[0027] Preferably, in step 1), the particles obtained by spray drying are also subjected to heat treatment.

[0028] Preferably, the heat treatment is carried out at a temperature of 900℃ to 1200℃.

[0029] Preferably, the particle size of the composite particles in step 1) is 30μm to 120μm.

[0030] Preferably, the thermal spraying method in step 2) is one of atmospheric plasma spraying, supersonic flame spraying, or supersonic cold spraying.

[0031] Preferably, the substrate in step 2) is one of carbon steel, stainless steel, or titanium alloy.

[0032] A chromium oxide-based coating, which is prepared by the above-described method.

[0033] Preferably, the thickness of the chromium oxide-based coating is 200 μm to 300 μm.

[0034] A metal component having the above-mentioned chromium oxide-based coating on its surface.

[0035] The beneficial effects of the present invention are: the chromium oxide-based coating of the present invention has both high hardness and excellent toughness, exhibiting excellent friction and wear resistance, and can be used as a wear-resistant coating on the surface of metal parts, making it suitable for large-scale industrial applications.

[0036] Specifically:

[0037] This invention designs the composition and proportion of powder materials and the microstructure of the coating. A composite ceramic coating with fully integrated additive phase and chromium oxide material is obtained through thermal spraying. The fine-particle phase material in the chromium oxide-based coating is uniformly distributed inside the coating and is mutually integrated with the chromium oxide component in the coating. The composite ceramic coating has low porosity and good interface bonding with the substrate. In terms of mechanical properties, the coating has high hardness and excellent toughness, exhibiting excellent friction and wear resistance. Attached Figure Description

[0038] Figure 1 This is a SEM image of the chromium oxide-based coating in Example 1.

[0039] Figure 2 The image shows the EDS spectrum of the chromium oxide-based coating in Example 1.

[0040] Figure 3 The image shows the Vickers hardness test results of the cross section and surface of the chromium oxide-based coating in Example 1.

[0041] Figure 4 The image shows a SEM image of the chromium oxide-based coating in Example 1 after being subjected to an indentation load of 20 N.

[0042] Figure 5 This is a SEM image of the surface of the chromium oxide-based coating in Example 1 after it has been rubbed.

[0043] Figure 6 The image shows the Vickers hardness test results of the cross section and surface of the chromium oxide-based coating in Example 2.

[0044] Figure 7 The image shows a SEM image of the chromium oxide-based coating in Example 2 after being subjected to an indentation load of 20 N.

[0045] Figure 8 This is a SEM image of the chromium oxide-based coating surface after it has been abraded in Example 2.

[0046] Figure 9 The image shows the Vickers hardness test results of the cross section and surface of the chromium oxide-based coating in Example 3.

[0047] Figure 10 The image shows a SEM image of the chromium oxide-based coating in Example 3 after being subjected to an indentation load of 20 N.

[0048] Figure 11 This is a SEM image of the surface of the chromium oxide-based coating in Example 3 after it has been rubbed.

[0049] Figure 12 The surface profile curve of the chromium oxide-based coating in Example 3 is the radial direction of the annular friction mark after being rubbed.

[0050] Figure 13 The image shows the SEM image of the chromium oxide-based coating in Comparative Example 1 after it has been rubbed.

[0051] Figure 14 The image shows a cross-section of the chromium oxide-based coating in Comparative Example 2 using SEM.

[0052] Figure 15 The polarization curves of the chromium oxide-based coatings in Example 3 and Comparative Example 3 in a 3.5% NaCl solution are shown. Detailed Implementation

[0053] The present invention will be further explained and described below with reference to specific embodiments.

[0054] Example 1:

[0055] A chromium oxide-based coating is prepared by the following method:

[0056] 1) Spherical alumina particles with a particle size of 0.5μm to 5μm (purity greater than 99%), chromium oxide particles with a particle size of 10μm to 30μm (purity greater than 99%), and polyvinyl alcohol (number average molecular weight of 120,000) are stirred and dispersed in water. The mass ratio of spherical alumina particles to chromium oxide particles is 1:20. The amount of polyvinyl alcohol is 10% of the total weight of spherical alumina particles and chromium oxide particles, and the amount of water is 1 times the total weight of spherical alumina particles and chromium oxide particles. Then, spray drying is performed, followed by heat treatment at 1000℃ for 30 minutes, and then passing through a 180-mesh sieve and a 300-mesh sieve to obtain composite particles with a particle size of 50μm to 80μm.

[0057] 2) The carbon steel is sandblasted, ultrasonically cleaned with acetone for 30 minutes, and dried. Then, the composite particles are thermally sprayed onto the carbon steel surface using an atmospheric plasma spraying system. During the spraying process, argon is used as the main gas to form the plasma arc, and hydrogen is used as the auxiliary gas. The pressures of the main gas and the auxiliary gas are controlled at 0.4MPa and 0.25MPa, respectively, and the flow rate of the main gas is controlled at 50L / min. The spraying voltage is controlled by adjusting the flow rate of the auxiliary hydrogen gas, thereby adjusting the spraying power. The plasma spray gun power is controlled at 39kW, the current is controlled at 650A, the voltage is controlled at 60V, the distance between the nozzle and the carbon steel is controlled at 80mm, the spray gun moving speed is maintained at 150mm / s, the powder carrier gas flow rate is controlled at 9L / min, and the powder feeder speed is controlled at 1.5r / min, thus obtaining a chromium oxide-based coating (thickness approximately 300μm).

[0058] Performance testing:

[0059] 1) The scanning electron microscope (SEM) image of the chromium oxide-based coating in this embodiment is shown below. Figure 1(a is the SEM image of the cross section, and b is the SEM image of the surface) as shown.

[0060] Depend on Figure 1 It can be seen that the chromium oxide-based coating has a good interface with carbon steel, there are no cracks or defects near the interface, the coating has few pores with a porosity of less than 2%, and there is no obvious separation between the two materials, spherical alumina particles and chromium oxide particles, in the coating.

[0061] 2) The EDS spectrum of the chromium oxide-based coating in this embodiment is as follows: Figure 2 As shown.

[0062] Depend on Figure 2 It can be seen that the aluminum and chromium elements are evenly distributed inside the chromium oxide-based coating, indicating that the two materials, spherical alumina particles and chromium oxide particles, are fully and evenly fused together.

[0063] 3) The Vickers hardness of the cross-section and surface of the chromium oxide-based coating in this embodiment was tested using a Vickers hardness tester. The test conditions were a 300g indentation load and a holding time of 15s. The test results are as follows: Figure 3 As shown.

[0064] Depend on Figure 3 It can be seen that the Vickers hardness of the chromium oxide-based coating is approximately 1600 HV. 0.3 The coating has high hardness on both the surface and cross-section, and strong resistance to damage and deformation.

[0065] 4) A Vickers hardness tester was used to apply an indentation load of 20 N to the surface of the chromium oxide-based coating in this embodiment, and then the surface morphology was tested. The obtained SEM image is shown below. Figure 4 As shown.

[0066] Depend on Figure 4 It can be seen that the crack did not propagate even under high concentrated load, indicating that the coating has excellent toughness and the crack is not easy to initiate and propagate.

[0067] 5) The friction performance of the chromium oxide-based coating in this embodiment was evaluated using an MS-T3001 friction and wear tester. The friction method was a ball-and-disc type, with tungsten carbide and silicon nitride balls of diameter Φ4. During the friction test, the grinding balls were fixed, while the sample stage rotated in a circular motion at a speed of 200 r / min for 2 hours. The load was 10 N. Before the friction test, the coating surface was ground and polished to a mirror finish. The mass of the sample was weighed using an electronic analytical balance before and after the friction test. The test results showed that after 2 hours of testing under the above various friction and wear conditions, there was no loss in the mass of the coating. The SEM image of the coating surface after friction is shown below. Figure 5 As shown.

[0068] Depend on Figure 5It can be seen that the chromium oxide-based coating has a relatively dense surface and contains small shell-like pits, but there is no large-scale peeling of the coating, indicating that it has excellent wear resistance.

[0069] Example 2:

[0070] A chromium oxide-based coating is prepared by the following method:

[0071] 1) Spherical Ti particles with a particle size of 1μm to 10μm (purity greater than 99.5%), chromium oxide particles with a particle size of 20μm to 50μm (purity greater than 99.5%), and polyacrylic acid (number average molecular weight of 130,000) were stirred and dispersed in water. The mass ratio of spherical Ti particles to chromium oxide particles was 1:19. The amount of polyacrylic acid was 10% of the total weight of spherical Ti particles and chromium oxide particles, and the amount of water was 1 times the total weight of spherical Ti particles and chromium oxide particles. The mixture was then ball-milled for 4 hours, spray-dried, and then passed through a 180-mesh sieve and a 300-mesh sieve to obtain composite particles with a particle size of 50μm to 80μm.

[0072] 2) The 304 stainless steel was sandblasted, ultrasonically cleaned with ethanol for 30 minutes, and dried. Then, the composite particles were thermally sprayed onto the surface of the 304 stainless steel using a supersonic flame spraying system. During the spraying process, oxygen and propane were used as combustion gases, and the flow rates of oxygen and propane were controlled to be 80 L / min and 20 L / min, respectively. The spraying distance was maintained at 100 mm, the moving speed of the spray gun was 200 mm / s, and the powder feeding speed during the spraying process was 10 g / min, thus obtaining a chromium oxide-based coating (thickness of about 200 μm).

[0073] Performance testing:

[0074] 1) The Vickers hardness of the cross-section and surface of the chromium oxide-based coating in this embodiment was tested using a Vickers hardness tester. The test conditions were an indentation load of 300g and a holding time of 15s. The test results are as follows: Figure 6 As shown.

[0075] Depend on Figure 6 It can be seen that the Vickers hardness of the chromium oxide-based coating is approximately 1700 HV. 0.3 ~1800HV 0.3 It is significantly higher than that of chromium oxide and chromium oxide-based coatings reported in current literature.

[0076] 2) A Vickers hardness tester was used to apply an indentation load of 20 N to the surface of the chromium oxide-based coating in this embodiment, and then the surface morphology was tested. The obtained SEM image is shown below. Figure 7 As shown.

[0077] Depend on Figure 7It can be seen that the chromium oxide-based coating does not crack under high concentrated loads, indicating that the coating has excellent toughness.

[0078] 3) The friction performance of the chromium oxide-based coating in this embodiment was evaluated using an MS-T3001 friction and wear tester. The friction method was a ball-and-disc type, with tungsten carbide and silicon nitride balls of diameter Φ4. During the friction test, the grinding balls were fixed, while the sample stage rotated in a circular motion at a speed of 200 r / min for 2 hours. The load was 10 N. Before the friction test, the coating surface was ground and polished to a mirror finish. The mass of the sample was weighed using an electronic analytical balance before and after the friction test. The test results showed that the coating mass was not lost after 2 hours of testing under the above various friction and wear conditions. The SEM image of the coating surface after friction is shown below. Figure 8 As shown.

[0079] Depend on Figure 8 It can be seen that no pitting or microcracks were observed on the surface of the chromium oxide-based coating, indicating that it has excellent friction and wear resistance. At the same time, a lubricating film was observed to form on the coating surface, which can play a role in protecting the coating to a certain extent.

[0080] Example 3:

[0081] A chromium oxide-based coating is prepared by the following method:

[0082] 1) Spherical alumina ceramic particles with a particle size of 0.2μm to 1μm (purity greater than 99.5%), spherical Ti particles with a particle size of 1μm to 10μm (purity greater than 99.5%), chromium oxide particles with a particle size of 20μm to 50μm (purity greater than 99.5%), and polysilazane (number average molecular weight of 150,000) were stirred and dispersed in water. The mass ratio of spherical alumina ceramic particles, spherical Ti particles, and chromium oxide particles was 2:1:17. The amount of polysilazane was 10% of the total weight of spherical alumina ceramic particles, spherical Ti particles, and chromium oxide particles, and the amount of water was 1 times the total weight of spherical alumina ceramic particles, spherical Ti particles, and chromium oxide particles. The mixture was then mixed in a high-speed mixer for 30 minutes, spray dried, and then passed through a 180-mesh sieve and a 300-mesh sieve to obtain composite particles with a particle size of 50μm to 80μm.

[0083] 2) The titanium alloy (Ti-6Al-4V) was sandblasted, ultrasonically cleaned with acetone for 30 minutes, and dried. Then, the composite particles were thermally sprayed onto the surface of the titanium alloy using a cold spraying system. During the spraying process, the nitrogen pressure of the spray gun was set to 3MPa, the distance between the nozzle and the substrate surface was kept at 50mm, the nitrogen flow rate was 25L / min, and the moving speed of the spray gun was 100mm / s, thus obtaining a chromium oxide-based coating (thickness of about 200μm).

[0084] Performance testing:

[0085] 1) The Vickers hardness of the cross-section and surface of the chromium oxide-based coating in this embodiment was tested using a Vickers hardness tester. The test conditions were an indentation load of 300g and a holding time of 15s. The test results are as follows: Figure 9 As shown.

[0086] Depend on Figure 9 It can be seen that the Vickers hardness of the chromium oxide-based coating is approximately 1750 HV. 0.3 This breaks through the current traditional chromium oxide coating's 1200HV limit. 0.3 ~1300HV 0.3 The bottleneck has excellent hardness.

[0087] 2) A Vickers hardness tester was used to apply an indentation load of 20 N to the surface of the chromium oxide-based coating in this embodiment, and then the surface morphology was tested. The obtained SEM image is shown below. Figure 10 As shown.

[0088] Depend on Figure 10 It can be seen that the chromium oxide-based coating is not prone to cracking under high concentrated loads. The excellent microstructure of the coating effectively hinders the initiation and propagation of cracks, indicating that the coating has excellent toughness.

[0089] 3) The friction performance of the chromium oxide-based coating in this embodiment was evaluated using an MS-T3001 friction and wear tester. The friction method was a ball-and-disc type, with tungsten carbide and silicon nitride balls of diameter Φ4. During the friction test, the grinding balls were fixed, and the sample stage rotated in a circular motion at a speed of 200 r / min for 2 hours. The loads were 5 N and 10 N. Before the friction test, the coating surface was ground and polished to a mirror finish. The mass of the sample was weighed using an electronic analytical balance before and after the friction test. The test results showed that after 2 hours of testing under the above various friction and wear conditions, there was no loss in the mass of the coating. The SEM image of the coating surface after friction is shown below. Figure 11 As shown, the surface profile curve measured along the radial direction of the annular friction mark is as follows: Figure 12 As shown.

[0090] Depend on Figure 11 It can be seen that there is a clear circular friction mark, but there is no material loss due to friction, and the coating integrity is relatively high.

[0091] Depend on Figure 12 It can be seen that no grooves appeared after friction, and there was no significant loss of coating volume due to wear on the grinding surface. This indicates that the chromium oxide-based coating has excellent wear resistance, and high-hardness materials such as tungsten carbide and silicon nitride are unlikely to damage the coating surface by friction.

[0092] Comparative Example 1:

[0093] A chromium oxide-based coating is identical to Example 1, except that the "spherical alumina particles with a particle size of 0.5 μm to 5 μm" in step 1) is changed to "spherical alumina particles with a particle size of 5 μm to 10 μm" during preparation.

[0094] Performance testing:

[0095] The SEM image of the chromium oxide-based coating surface in this comparative example after being rubbed is shown below. Figure 13 (The testing process is the same as in Example 3).

[0096] Depend on Figure 13 It can be seen that the large-area peeling of the chromium oxide-based coating indicates that increasing the particle size of alumina particles will reduce the uniformity and adhesion of the coating, resulting in a decrease in the hardness and wear resistance of the coating.

[0097] Comparative Example 2:

[0098] A chromium oxide-based coating is identical to Example 1, except that the "chromium oxide particles with a particle size of 10 μm to 30 μm" in step 1) is changed to "chromium oxide particles with a particle size of 1 μm to 10 μm" during preparation.

[0099] Performance testing:

[0100] The SEM image of the cross-section of the chromium oxide-based coating in this comparative example is shown below. Figure 14 As shown.

[0101] Depend on Figure 14 It can be seen that there are many pores in the chromium oxide-based coating and poor compactness. This indicates that reducing the particle size of chromium oxide particles is beneficial to improving the compactness and mechanical properties of the coating. However, too small a particle size will lead to uneven distribution of chromium oxide in the coating and affect the overall performance of the coating.

[0102] Comparative Example 3:

[0103] A chromium oxide-based coating is identical to that in Example 3, except that the mass ratio of spherical alumina particles, spherical Ti particles, and chromium oxide particles in step 1) is adjusted from "2:1:17" to "2:1:7".

[0104] Performance testing:

[0105] The polarization curves of the chromium oxide-based coating in Example 3 and the chromium oxide-based coating in this comparative example in a 3.5% NaCl solution are as follows: Figure 15 As shown.

[0106] Depend on Figure 15 It can be seen that the self-corrosion potential of the chromium oxide-based coating in this comparative example is -0.53V, and the self-corrosion current is 1.27 × 10⁻⁶.-6 A / cm 2 In contrast, the chromium oxide-based coating in Comparative Example 3 had a self-corrosion potential of -0.57V and a self-corrosion current of 8.02 × 10⁻⁶. -6 A / cm 2 The chromium oxide-based coating in Comparative Example 3 exhibited poor corrosion resistance, indicating that increasing the proportion of spherical alumina particles and spherical Ti particles, as well as decreasing the proportion of chromium oxide particles, would lead to an increase in the coating's hardness. However, an excessively high proportion of ceramic and metal particles would affect the coating's corrosion resistance.

[0107] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a chromium oxide-based coating, characterized in that, Includes the following steps: 1) Ceramic particles and / or metal particles, chromium oxide particles and binder are dispersed in water, with the particle size of ceramic particles and metal particles being smaller than that of chromium oxide particles, and then spray dried to obtain composite particles; 2) The composite particles are thermally sprayed onto the substrate surface to obtain a chromium oxide-based coating. Step 1) The ceramic particles are at least one of alumina ceramic particles, titanium dioxide ceramic particles, zirconia ceramic particles, and yttrium oxide-stabilized zirconia ceramic particles; Step 1) The particle size of the ceramic particles is 0.5μm to 5μm; Step 1) The metal particles are spherical Ti particles; Step 1) The particle size of the metal particles is 0.1 μm to 10 μm; Step 1) The particle size of the chromium oxide particles is 10 μm to 30 μm; Step 1) The mass ratio of the ceramic particles and / or metal particles and chromium oxide particles is 1:5 to 25.

2. The preparation method according to claim 1, characterized in that: Step 1) The particle size of the composite particles is 30μm to 120μm.

3. The preparation method according to claim 1, characterized in that: Step 2) The thermal spraying method is one of atmospheric plasma spraying, supersonic flame spraying, or supersonic cold spraying.

4. The preparation method according to claim 1 or 3, characterized in that: Step 2) The substrate is one of carbon steel, stainless steel, or titanium alloy.

5. A chromium oxide-based coating, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 4.

6. The chromium oxide-based coating according to claim 5, characterized in that: The thickness of the chromium oxide-based coating is 200 μm to 300 μm.

7. A metal component, characterized in that, The surface is covered with the chromium oxide-based coating as described in claim 5 or 6.

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