High-entropy alloy metal ceramic composite coating resistant to high-temperature abrasion

Abstract

The invention relates to the technical field of metal ceramic composite coatings, and provides a high-temperature-wear-resistant high-entropy alloy metal ceramic composite coating which is prepared through the following steps that Y / Hf-Ni CoCrAl Fe series high-entropy alloy and ceramic particles are mixed in proportion to form a prefabricated coating; a grinding machine is used for grinding the prefabricated coating; the surface of the base body is subjected to sand blasting decontamination and nitriding treatment; a nickel-based alloy is smeared on the base body; the prefabricated coating is bonded to a base body through an organic bonding agent; laser cladding equipment is adopted for carrying out cladding treatment on the base body; grinding and polishing post-treatment procedures are carried out on the clad composite coating, and performance testing is carried out, so that the performance of the coating is evaluated; nitrogen atoms permeate into the surface layer of a base material and react with base material atoms to generate nitride, so that the hardness of the surface is enhanced, the hardness and wear resistance of the coating are further improved through the laser cladding technology of the nickel-based alloy and the reinforced-phase tungsten carbide, and the bonding strength is greatly improved while the toughness of the composite coating is kept.

Description

Technical Field

[0001] The invention relates to the technical field of metal ceramic composite coatings, in particular to a high-entropy alloy metal ceramic composite coating resistant to high temperature wear. Background Art

[0002] As a high-performance coating material, metal-ceramic composite coating has attracted widespread attention due to its unique composite properties. This coating combines the high hardness, high melting point and high thermal stability of the ceramic phase with the high strength, high toughness and high plasticity of the metal bonding phase, thus showing great potential in a variety of application scenarios, especially in friction and wear environments that need to withstand corrosion and high temperature conditions.

[0003] However, in the existing metal-ceramic composite coating preparation technology, a common problem is the addition of tungsten carbide (WC). Tungsten carbide is a material with extremely high hardness and is often used to enhance the wear resistance of the coating. However, when the tungsten carbide content is too high, it will cause the toughness of the coating to be significantly reduced. This is because the tungsten carbide particles have a high hardness and relatively weak bonding with the metal bonding phase, which easily forms stress concentration points in the coating. When the coating is subjected to external forces, these stress concentration points are prone to cause cracks, which in turn cause brittle cracking of the coating as a whole. This causes the coating to undergo brittle fracture when subjected to a small external force, seriously affecting the overall performance and service life of the coating.

[0004] Therefore, how to maintain the high hardness of the metal-ceramic composite coating while improving its toughness and avoiding brittle cracking has become a technical problem that needs to be solved urgently. In order to solve this problem, researchers are exploring new preparation processes and coating materials, hoping to improve its toughness by optimizing the coating structure and composition while maintaining the strengthening effect of tungsten carbide. Summary of the invention

[0005] The present invention provides a high-entropy alloy metal-ceramic composite coating resistant to high temperature wear, wherein nitrogen atoms penetrate into the surface layer of a base material and react with the base material atoms to form nitrides, thereby enhancing the hardness of the surface, and further improves the hardness and wear resistance of the coating by laser cladding technology of a nickel-based alloy and a reinforcing phase tungsten carbide, thereby solving the problems existing in the background technology.

[0006] The technical solution of the present invention is as follows:

[0007] A high-entropy alloy metal-ceramic composite coating resistant to high temperature wear, comprising a Y / Hf-NiCoCrAlFe series high-entropy alloy and ceramic particles, and further comprising the following steps:

[0008] S1, mixing Y / Hf-NiCoCrAlFe series high entropy alloy and ceramic particles in a ratio of 2:1 to form a prefabricated coating;

[0009] S2. Grind the prefabricated coating with a grinder. The grinding process can remove impurities and bubbles in the coating material, improve the purity and density of the coating, and improve the particle shape and distribution of the coating material, making it more suitable for subsequent coating processes. Grind until the average particle size of the powder is 1 to 10 μm.

[0010] S3, sandblasting and decontamination of the substrate surface of the bottom layer and nitriding treatment;

[0011] S4, applying nickel-based alloy on the substrate;

[0012] S5, bonding the prefabricated coating to the substrate using an organic binder;

[0013] S6. Use laser cladding equipment to clad the substrate. Laser cladding technology can achieve metallurgical bonding between the coating and the substrate, improve the bonding strength and toughness of the coating, and at the same time, by precisely controlling the laser parameters, the microstructure and performance of the coating can be optimized;

[0014] S7. The clad composite coating is subjected to post-processing steps of grinding and polishing, and performance tests such as hardness test and wear resistance test are performed to evaluate the performance of the coating.

[0015] As a technical solution of the present invention, the ceramic particles in S1 are composed of 20-43% tungsten carbide, 20-35% silicon dioxide, 16-30% titanium powder, 5-10% graphite powder and 3-6% quartz.

[0016] As a technical solution of the present invention, S2 needs to be ground for 8 to 10 hours, then an organic binder is added and grinding is continued for 1 to 2 hours.

[0017] As a technical solution of the present invention, in S3, nitridation treatment is performed by electrolytic plasma to penetrate nitrogen atoms into the surface layer of the base material and react with the atoms of the base material to form nitride, thereby enhancing the hardness of the surface.

[0018] As a technical solution of the present invention, the substrate in S3 is made of Q235 steel. The nickel-based alloy has extremely high wettability to the steel substrate and can form a deep metallurgical bond during the cladding process. This close bond helps to improve the bonding strength of the coating and thereby enhance the toughness of the coating.

[0019] As a technical solution of the present invention, the nickel-based alloy in S4 is composed of 40-57% nickel, 20-35% chromium, 8-30% molybdenum and 5%-10% niobium.

[0020] As a technical solution of the present invention, the thickness of the pre-coating in S5 is 70-100 μm.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention allows nitrogen atoms to penetrate into the surface layer of the base material and react with the base material atoms to form nitrides, thereby enhancing the hardness of the surface. The nickel-based alloy has a stable crystal structure, which enables it to maintain stable performance under extreme environments. This stability helps the coating to remain intact when subjected to stress and is not prone to breakage or peeling, thereby improving the toughness of the coating and making it less prone to brittle cracking. The nickel-based alloy has extremely high wettability to the steel substrate and can form a deep metallurgical bond during the cladding process. This close bond helps to improve the bonding strength of the coating, thereby enhancing the toughness of the coating. The nickel-based alloy and the reinforcing phase tungsten carbide are further improved through laser cladding technology to further improve the hardness and wear resistance of the coating, so that the composite coating maintains toughness while greatly improving the bonding strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a flow chart of the composite coating preparation method of the present invention. DETAILED DESCRIPTION

[0024] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0025] Embodiment 1

[0026] S1. Y / Hf-NiCoCrAlFe series high entropy alloy and ceramic particles are mixed in a ratio of 2:1 to form a prefabricated coating, wherein the ceramic particles are composed of 43% tungsten carbide, 25% silicon dioxide, 16% titanium powder, 10% graphite powder and 6% quartz;

[0027] S2, grinding the prefabricated coating with a grinder for 8 to 10 hours, adding an organic binder, and continuing to grind for 1 to 2 hours until the average particle size of the powder is 1 to 10 μm;

[0028] S3, sandblasting and decontamination of the substrate surface of the bottom layer and nitriding treatment;

[0029] S4. applying a nickel-based alloy on the substrate, wherein the nickel-based alloy consists of 57% nickel, 23% chromium, 10% molybdenum and 10% niobium;

[0030] S5, using an organic binder to bond the pre-coating to the substrate, and the thickness of the pre-coating is 100 μm;

[0031] S6. Using laser cladding equipment to perform cladding treatment on the substrate;

[0032] S7. The clad composite coating is subjected to post-processing steps of grinding and polishing, and performance testing is performed.

[0033] Embodiment 2

[0034] S1, mixing Y / Hf-NiCoCrAl Fe series high entropy alloy and ceramic particles in a ratio of 2:1 to form a prefabricated coating, wherein the ceramic particles are composed of 20% tungsten carbide, 35% silicon dioxide, 29% titanium powder, 10% graphite powder and 6% quartz;

[0035] S2, grinding the prefabricated coating with a grinder for 8 to 10 hours, adding an organic binder, and continuing to grind for 1 to 2 hours until the average particle size of the powder is 1 to 10 μm;

[0036] S3, sandblasting and decontamination of the substrate surface of the bottom layer and nitriding treatment;

[0037] S4. Applying a nickel-based alloy on the substrate, wherein the nickel-based alloy consists of 40% nickel, 30% chromium, 20% molybdenum and 10% niobium;

[0038] S5, using an organic binder to bond the pre-coating to the substrate, and the thickness of the pre-coating is 70 μm;

[0039] S6. Using laser cladding equipment to perform cladding treatment on the substrate;

[0040] S7. The clad composite coating is subjected to post-processing steps of grinding and polishing, and performance testing is performed.

[0041] Embodiment 3

[0042] S1, mixing Y / Hf-NiCoCrAl Fe series high entropy alloy and ceramic particles in a ratio of 2:1 to form a prefabricated coating, wherein the ceramic particles are composed of 30% tungsten carbide, 28% silicon dioxide, 26% titanium powder, 10% graphite powder and 6% quartz;

[0043] S2, grinding the prefabricated coating with a grinder for 8 to 10 hours, adding an organic binder, and continuing to grind for 1 to 2 hours until the average particle size of the powder is 1 to 10 μm;

[0044] S3, sandblasting and decontamination of the substrate surface of the bottom layer and nitriding treatment;

[0045] S4. applying a nickel-based alloy on the substrate, wherein the nickel-based alloy consists of 50% nickel, 20% chromium, 23% molybdenum and 7% niobium;

[0046] S5, using an organic binder to bond the pre-coating to the substrate, wherein the thickness of the pre-coating is 88 μm;

[0047] S6. Using laser cladding equipment to perform cladding treatment on the substrate;

[0048] S7. The clad composite coating is subjected to post-processing steps of grinding and polishing, and performance testing is performed.

[0049] Comparative Example 1

[0050] This comparative example provides a high-entropy alloy metal-ceramic composite coating that is resistant to high-temperature wear, and the details are shown in Example 1, except that the substrate is not subjected to nitriding treatment.

[0051] Comparative Example 2

[0052] This comparative example provides a high-entropy alloy metal-ceramic composite coating that is resistant to high-temperature wear, and the details are shown in Example 1, except that the nickel-based alloy is not applied on the substrate.

[0053] Performance Testing

[0054] Tensile test method:

[0055] 1. Install the specimen in the fixture of the tensile testing machine, ensuring that the specimen and the fixture are well aligned and that the fixture does not damage the coating;

[0056] 2. Start the tensile testing machine and stretch the specimen at a constant speed;

[0057] 3. Record the tensile force and displacement data during the stretching process until the coating is damaged;

[0058] 4. Evaluate the bonding strength, elastic modulus and other parameters of the coating based on the tensile test data;

[0059] Thermal shock performance test:

[0060] Keep the sample in a high-temperature furnace for 15 minutes, then quench it directly in cold water, take out the sample from the water, wipe it clean, place the sample on a plate with a thin layer of fine alumina powder, roll it back and forth several times or hold the sample in your hand and rub it on the alumina powder several times, check whether it is cracked (if cracked, there will be a white crack on the surface), and record it in detail, put the sample without cracks into the furnace, heat it to the next specified temperature (each time at an interval of 20°C), and repeat the test until all the samples are cracked.

[0061] Friction and wear testing:

[0062] Use CFT-1 ultra-functional wear tester or UMT-3 friction tester to conduct friction and wear tests;

[0063] The parameters were set as 60 min sliding time, 300 rpm / min rotation speed, 3 mm friction radius and 4 N load;

[0064] Si3N4 ceramic balls were selected for friction testing, and the friction coefficient and wear volume were recorded.

[0065]

[0066]

[0067] From the above table, it can be seen that the maximum external force value that the composite coating of Examples 1-3 can withstand is as high as 901HV, the wear rate is as low as 1.63×10-8mm3 / Nm, and the thermal stability can be repeated 263 times. It has excellent wear resistance and thermal stability as well as high bonding strength. Examples 1-3 enhance the hardness of the surface by infiltrating nitrogen atoms into the surface layer of the base material and reacting with the base material atoms to form nitrides. The nickel-based alloy has a stable crystal structure, which enables it to maintain stable performance in extreme environments. This stability helps the coating to remain intact when subjected to force and is not easy to develop. The nickel-based alloy has extremely high wettability to the steel substrate and can form a deep metallurgical bond during the cladding process. This close bond helps to improve the bonding strength of the coating, thereby enhancing the toughness of the coating. The nickel-based alloy and the reinforcing phase tungsten carbide are further clad by laser cladding technology to further improve the hardness and wear resistance of the coating, thereby greatly improving the bonding strength of the composite coating. It can be seen from Comparative Examples 1 and 2 that the substrate not nitrided or coated with a nickel-based alloy layer has a negative impact on the wear rate and bonding strength.

[0068] The embodiments of the present invention are provided for the purpose of illustration and description. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A high-entropy alloy metal-ceramic composite coating resistant to high temperature wear, comprising a Y / Hf-NiCoCrAlFe series high-entropy alloy and ceramic particles, characterized in that: The following steps are also included: S1, mixing the Y / Hf-NiCoCrAlFe series high entropy alloy and ceramic particles in a ratio of 2:1 to form a prefabricated coating; S2, grinding the prefabricated coating using a grinder until the average particle size of the powder is 1 to 10 μm; S3, sandblasting and decontamination of the substrate surface of the bottom layer and nitriding treatment; S4, applying nickel-based alloy on the substrate; S5, bonding the prefabricated coating to the substrate using an organic binder; S6. Using laser cladding equipment to perform cladding treatment on the substrate surface to form a composite coating on the substrate surface; S7. The clad composite coating is subjected to post-processing steps of grinding and polishing, and performance testing is performed to evaluate the performance of the coating.

2. A high-entropy alloy metal-ceramic composite coating resistant to high temperature wear as claimed in claim 1, characterized in that: The ceramic particles in S1 are composed of 20-43% tungsten carbide, 20-35% silicon dioxide, 16-30% titanium powder, 5-10% graphite powder and 3-6% quartz.

3. A high-entropy alloy metal-ceramic composite coating resistant to high temperature wear as claimed in claim 1, characterized in that: S2 needs to be ground for 8 to 10 hours, then an organic binder is added and grinding is continued for 1 to 2 hours.

4. A high-entropy alloy metal-ceramic composite coating resistant to high temperature wear as claimed in claim 1, characterized in that: In S3, nitriding treatment is performed by electrolytic plasma.

5. A high-entropy alloy metal-ceramic composite coating resistant to high temperature wear as claimed in claim 1, characterized in that: The substrate described in S3 is made of Q235 steel.

6. A high-entropy alloy metal-ceramic composite coating resistant to high temperature wear as claimed in claim 1, characterized in that: The nickel-based alloy described in S4 is composed of 40-57% nickel, 20-35% chromium, 8-30% molybdenum and 5%-10% niobium.

7. A high-entropy alloy metal-ceramic composite coating resistant to high temperature wear as claimed in claim 1, characterized in that: The thickness of the pre-coating layer in S5 is 70-100 μm.

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