Coating formula based on tungsten carbide

Abstract

The invention relates to the technical field of tungsten carbide coatings, and discloses a coating formula based on tungsten carbide, the coating formula comprises 80-85% of hard particle material, 5-10% of binder, 3-5% of additive and 5-8% of solvent, the hard particle material comprises the following components: WC powder; high-entropy alloy powder; and rare earth element powder. When the coating formula based on tungsten carbide is applied, the bonding strength and toughness of the coating and a matrix can be improved, the service life of the coating is prolonged, the reliability of the coating is improved, the heat conduction performance and the thermal expansion coefficient of the coating are improved, the stripping and falling phenomena are reduced, and the problem that in the prior art, although a tungsten carbide coating is very high in hardness, the coating cannot be damaged easily is solved. The problems of high wear resistance and poor toughness are solved, so that the coating can be applied to complex scenes requiring high wear resistance and high toughness.

Description

Technical Field

[0001] The invention relates to the technical field of tungsten carbide coatings, and in particular to a coating formula based on tungsten carbide. Background Art

[0002] WC (tungsten carbide) hard facing material has become the most widely used hard facing coating material due to its high hardness, excellent wear resistance and corrosion resistance. The most notable feature of WC is its high hardness, which can reach 2100HV, close to that of diamond. The metal tungsten and non-metallic carbon in WC produce a very strong covalent bond, which hinders the slip in the WC crystal and strengthens the WC crystal. However, WC itself has poor toughness and is not suitable for use alone in products with high comprehensive performance requirements. Generally, self-fluxing alloys such as Co (cobalt), Ni (nickel), and Fe (iron) need to be added as a bonding phase to make the high hardness of WC work. Thermal spray alloy powders include nickel-based, iron-based and cobalt-based alloy powders.

[0003] The bonding phase is an important component of WC hard surface material, which plays the role of fixing WC particles, bearing and transmitting various loads. At the same time, it gives the hard surface coating strength, toughness, corrosion resistance, etc. At present, the single principal alloy bonding phase commonly used in WC hard surface coatings, such as Fe, Co, Ni-based alloys, etc., and the WC coating prepared by the single principal alloy bonding phase has the following shortcomings:

[0004] 1. Mechanical properties: Although traditional WC coatings have high hardness, they usually perform poorly in toughness. This is because single or low-complexity metal binders such as Co or Ni may not be able to provide sufficient adhesion while being insufficient to resist high impact or high deformation application environments;

[0005] 2. Corrosion resistance: The corrosion resistance of WC coating mainly depends on the chemical stability of the binder. Traditional binders such as Co and Ni may perform poorly in certain corrosive environments, especially in environments containing strong oxidants or acidic substances;

[0006] 3. High temperature performance: In high temperature applications, traditional WC coatings may suffer from performance degradation due to oxidation or softening of binders such as Co elements;

[0007] 4. Heat treatment and manufacturing complexity: The heat treatment and manufacturing processes of traditional WC coatings can be complex, especially when it comes to precisely controlling composition and phase changes.

[0008] Therefore, it is necessary to design a tungsten carbide-based coating formulation to solve the above problems. Summary of the invention

[0009] The purpose of the present invention is to solve the shortcomings in the prior art and to propose a coating formula based on tungsten carbide.

[0010] In order to achieve the above object, the present invention adopts the following technical solutions:

[0011] A coating formula based on tungsten carbide includes a hard particle material, a binder, an additive and a solvent, wherein the content of the hard particle material is 80% to 85%, the content of the binder is 5% to 10%, the content of the additive is 3% to 5%, and the content of the solvent is 5% to 8%. The hard particle material includes the following components:

[0012] WC powder as the wear-resistant main body: WC powder content is 85% to 88%;

[0013] High entropy alloy powder as a bonding phase: the content of high entropy alloy powder is 8% to 10%;

[0014] Rare earth element powder for modulation: the content of rare earth element powder is 2% to 5%.

[0015] As a preferred technical solution of the present invention, the high entropy alloy powder is AlCoCrFeNiMn. Calculated based on the total weight of AlCoCrFeNiMn itself as 100%, the content of Co is 50% to 60%, the content of Cr is 25% to 30%, the content of Al is 5% to 8%, the content of Fe is 5% to 8%, the content of Mn is 2% to 5%, and the balance is Ni.

[0016] As a preferred technical solution of the present invention, the rare earth element powder includes Y and Ti. Taking the total weight of the rare earth element powder as 100%, the content of Y is 30% to 50%, and the content of Ti is 50% to 70%.

[0017] As a preferred technical solution of the present invention, the component of the adhesive is epoxy resin, the component of the additive is antioxidant or anti-ultraviolet agent, and the solvent is ethanol.

[0018] As a preferred technical solution of the present invention, AlCoCrFeNiMn powder is prepared by gas atomization method, and the preparation process includes the following steps:

[0019] S1, pouring AlCoCrFeNiMn powder raw materials into a crucible according to proportion, and melting the AlCoCrFeNiMn raw materials by induction heating to obtain AlCoCrFeNiMn alloy liquid;

[0020] S2, the AlCoCrFeNiMn alloy liquid is crushed by a tightly coupled atomization method to form alloy powder, the atomization medium is argon gas, and the atomization pressure is 3MPa~4MPa.

[0021] As a preferred technical solution of the present invention, the production process of the coating formulation based on tungsten carbide includes:

[0022] SS1, mixing: adding the hard particle material, binder, additive and solvent into a stirring device according to a proportion, stirring at a speed of 100 r / min to 200 r / min, and mixing for 40 min to 60 min to obtain a mixed material;

[0023] SS2, drying: the mixed material is placed in a centrifugal spray dryer, the inlet air temperature of the spray drying is 150°C to 180°C, the outlet air temperature is 90°C to 140°C, the medium is nitrogen, the rotation frequency is 40Hz to 50Hz, the atomizing disk speed is 8000r / min to 10000r / min, the feed amount is 200mL / min to 400mL / min, and agglomerated particles are obtained after atomization drying;

[0024] SS3, debinding and sintering: The agglomerated particles are treated by debinding and sintering process to obtain a solidified material.

[0025] SS4, ball milling: add the solidified material into the ball mill for 6h to 8h, and obtain the spray powder after ball milling. The particle size of the spray powder is 8μm to 12μm.

[0026] As a preferred technical solution of the present invention, the degreasing stage in the degreasing sintering process is divided into:

[0027] SS301, heating stage: put the agglomerated particles in a hot degreasing furnace and heat them gradually to 200℃~400℃;

[0028] SS302, insulation stage: the agglomerated particles are kept at a temperature of 200°C to 400°C for 5h to 7h.

[0029] As a preferred technical solution of the present invention, the sintering stage in the debinding sintering process is divided into:

[0030] SS311, heating stage: using a high-temperature sintering furnace with precise temperature control and atmosphere control functions, slowly heat the degreased agglomerated particles to the sintering temperature, the sintering temperature is 1100°C to 1500°C, the sintering time is 5h to 7h, and product 1 is obtained;

[0031] SS312, cooling stage: slowly cool the product to room temperature to finally obtain a solidified material.

[0032] As a preferred technical solution of the present invention, the spraying powder prepared by the process comprises the following steps during spraying:

[0033] SSS1, before spraying, the spray powder is dried in a drying oven for 30min to 60min, and the drying temperature is maintained at 90℃ to 120℃;

[0034] SSS2, sandblasting, cleaning and drying of the substrate to be sprayed;

[0035] SSS3, adopts supersonic flame spraying process for spraying, the flame spray speed is greater than 3000m / s, the compressed air is dry, oil-free and clean, the pressure of compressed air is 0.2Mpa~0.4Mpa, during spraying, the temperature of the substrate does not exceed 100℃, the interlayer temperature does not exceed 150℃, and the thickness of each coating is not more than 10μm.

[0036] The present invention has the following beneficial effects:

[0037] 1. Improve the mechanical properties of the coating: AlCoCrFeNiMn high entropy alloy has excellent mechanical properties and thermal stability. Its addition can improve the toughness of the coating, increase the service life and reliability of the coating, and improve the bonding strength between the coating and the substrate. Therefore, its addition can improve the bonding performance between the coating and the substrate, reduce peeling and shedding phenomena, and improve the reliability and stability of the coating;

[0038] 2. Improve the high temperature resistance and cavitation resistance of the coating: The addition of AlCoCrFeNiMn high entropy alloy and Y and Ti elements can enhance the oxidation resistance and cavitation resistance of the coating, making the coating more suitable for working in harsh environments. Secondly, it can improve the thermal conductivity and thermal expansion coefficient of the coating, making the coating more suitable for application in high temperature working environments;

[0039] 3. Optimize microstructure and organizational morphology: The composite coating formed by AlCoCrFeNiMn high entropy alloy and WC has a uniform microstructure and dense organizational morphology, which is beneficial to improve the mechanical properties and chemical stability of the coating. The addition of Y and Ti elements can improve the processing properties of the coating, making it easier to spray, form and process, thereby improving production efficiency and process controllability. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The present invention provides a flow chart for preparing the tungsten carbide coating formula. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0042] A coating formula based on tungsten carbide includes a hard particle material, a binder, an additive and a solvent, wherein the content of the hard particle material is 80% to 85%, the content of the binder is 5% to 10%, the content of the additive is 3% to 5%, and the content of the solvent is 5% to 8%. The hard particle material includes the following components:

[0043] WC powder as the wear-resistant main body: WC powder content is 85% to 88%;

[0044] High entropy alloy powder as a bonding phase: the content of high entropy alloy powder is 8% to 10%, the high entropy alloy powder is AlCoCrFeNiMn, and based on the total weight of AlCoCrFeNiMn itself being 100%, the content of Co is 50% to 60%, the content of Cr is 25% to 30%, the content of Al is 5% to 8%, the content of Fe is 5% to 8%, the content of Mn is 2% to 5%, and the balance is Ni;

[0045] Rare earth element powder for modulation: the rare earth element powder content is 2% to 5%, the rare earth element powder includes Y and Ti, and based on the total weight of the rare earth element powder itself being 100%, the Y content is 30% to 50%, and the Ti content is 50% to 70%.

[0046] The component of the binder is epoxy resin, the component of the additive is antioxidant or anti-ultraviolet agent, the anti-ultraviolet agent is diphenol, in the process of making coating powder, ultraviolet radiation may degrade the resin matrix in the coating, adding anti-ultraviolet agent helps to protect the overall performance of the coating and prevent it from failing due to light aging, and the solvent is ethanol.

[0047] AlCoCrFeNiMn high entropy alloys have slow diffusion effect, high entropy effect and cocktail effect. The slow diffusion effect is due to the presence of multiple elements. The differences in atomic size, electronic structure and chemical properties between elements lead to a decrease in the diffusion coefficient. This slow diffusion effect means that at high temperatures, the mutual diffusion rate between alloy elements slows down, which helps to improve the creep resistance and stability of the alloy in high temperature environments. The high entropy effect means that when the alloy contains multiple main elements, due to the significant increase in configuration entropy, the alloy tends to form a simple solid solution phase rather than a complex metastable phase or compound. Configuration entropy is a thermodynamic concept that refers to the number of possible microscopic states in a system. At low temperatures, high configuration entropy helps stabilize simple solid solution structures, thereby enhancing the thermal stability of the alloy. The cocktail effect refers to the composite effect produced by the joint action of multiple elements in high entropy alloys. These effects often exceed the simple superposition of a single element and are the result of the interaction and synergy of multiple elements to enhance the overall performance of the material. Since AlCoCrFeNiMn high entropy alloys are composed of multiple atomic sizes and different elements, this complexity helps reduce lattice distortion and structural defects. This balanced chemical composition and structure can effectively inhibit the propagation of cracks. Based on the above effects, the toughness and thermal stability of the WC coating with the addition of AlCoCrFeNiMn powder will be improved.

[0048] Furthermore, the Ti powder selected is nano-metal titanium powder, which can improve the air tightness of the coating. Ti is a light but high-strength metal, which is often used in alloys to improve strength, hardness and corrosion resistance. The stability of Ti itself enables the coating to maintain its performance for a longer time and reduce material damage caused by chemical erosion, which is closely related to the chemical inertness and antioxidant properties of Ti. In the coating, Ti can form a compact Ti oxide layer, which can effectively protect the substrate material from corrosion and oxidation, improve the coating's resistance to chemical corrosion and oxidation, and improve the coating's cavitation resistance. More importantly, the introduction of Ti can improve the adhesion of the coating to the substrate, and the distribution of Ti powder in the coating can provide a better mechanical anchoring effect, which enhances the bonding strength between the coating and the substrate, which is related to the inherent properties of Ti. The chemical affinity and mechanical properties of the coating are related to its own, which can extend the service life of the coating; Y is also a rare earth element. It is mainly used in alloys to improve thermal stability and high-temperature oxidation resistance. In the coating, Y has a high melting point and good oxidation resistance. After adding Y element, the oxidation resistance and thermal stability of the coating can be improved. In addition, Y can inhibit the growth of grain boundaries and grain growth in tungsten carbide coatings, which helps to maintain a finer grain structure, thereby improving the toughness of the coating. The fine grain structure can make the coating deform and absorb energy more evenly when subjected to stress, reducing the risk of brittle fracture, improving the material's crack resistance, and reducing crack generation at high temperatures. Based on the performance of these elements, after adding these rare earth element powders, the toughness of the WC coating and the bonding strength between the coating and the substrate are improved.

[0049] AlCoCrFeNiMn powder is prepared by gas atomization. Gas atomization is a method of directly breaking liquid metal or alloy into fine droplets under the action of external force and quickly condensing to obtain powder. Compared with mechanical pulverization, gas atomization is a simpler and more economical powder production method. The preparation process includes the following steps:

[0050] S1, pouring AlCoCrFeNiMn powder raw materials into a crucible according to proportion, and melting the AlCoCrFeNiMn raw materials by induction heating to obtain AlCoCrFeNiMn alloy liquid;

[0051] S2, and then the AlCoCrFeNiMn alloy liquid is crushed by a close-coupled atomization method to form alloy powder. The atomization medium is argon gas, and the atomization pressure is 3MPa~4MPa. The close-coupled atomization method for powder preparation has the advantages of higher powder quality and uniformity, higher production efficiency, lower energy consumption, better operating stability and wider applicability. It is an advanced technology widely used in the field of powder preparation.

[0052] Reference Figure 1 , the production process of this formula includes:

[0053] SS1, mixing: adding the hard particle material, binder, additive and solvent into a stirring device according to a proportion, stirring at a speed of 100 r / min to 200 r / min, and mixing for 40 min to 60 min to obtain a mixed material;

[0054] SS2, drying: putting the mixed material into a centrifugal spray dryer. Specifically, the centrifugal spray drying system is a commonly used spray drying equipment, which is used to spray the liquid material into fine particles through the interaction of high-speed rotating centrifugal force and hot air flow, thereby realizing the process of converting the liquid material into dry solid particles. Its main structure includes a feeding system, a spray dryer, a hot air system, a separation system and a control system. The centrifugal spray drying system has a fast drying speed, which can greatly shorten the production cycle, and has higher energy utilization and lower exhaust gas emissions, which is conducive to energy conservation and emission reduction. The inlet temperature of the spray drying is 150℃~180℃, the outlet temperature is 90℃~140℃, the medium is nitrogen, the rotation frequency is 40Hz~50Hz, the atomizing disk speed is 8000r / min~10000r / min, the feed amount is 200mL / min~400mL / min, and agglomerated particles are obtained after atomization drying;

[0055] SS3, debinding and sintering: agglomerated particles are treated by debinding and sintering process to obtain solidified materials. The debinding stage in the debinding and sintering process is divided into: SS301, heating stage: agglomerated particles are placed in a hot debinding furnace, the furnace is kept in an inert atmosphere such as nitrogen or hydrogen, and gradient heating is performed to 200℃~400℃ to soften and decompose the organic binder; SS302, heat preservation stage: the agglomerated particles are kept at a temperature of 200℃~400℃ for 5h~7h, and the heat preservation treatment can ensure that the organic binder is fully decomposed. The sintering stages in the debinding and sintering process are divided into: SS311, heating stage: using a high-temperature sintering furnace with precise temperature control and atmosphere control functions, whose structure includes a furnace body, heating elements, temperature control system, atmosphere control system, sample support and carrier, safety system, and data recording and traceability system, the debinded agglomerated particles are slowly heated to the sintering temperature, the sintering temperature is 1100℃~1500℃, the sintering time is 5h~7h, and product one is obtained; SS311, cooling stage: product one is slowly cooled to room temperature to avoid rapid cooling causing material cracking or excessive internal stress, and finally a solidified material is obtained.

[0056] SS4, ball milling: add the solidified material into the ball mill for 6h to 8h, obtain the spray powder after ball milling, screen and grade the powder after ball milling, and the particle size of the spray powder is 8μm to 12μm.

[0057] The spraying powder prepared by the process comprises the following steps during spraying:

[0058] SSS1, before spraying, the spray powder is dried in a drying oven for 30min to 60min, and the drying temperature is maintained at 90℃ to 120℃;

[0059] SSS2, the substrate to be sprayed is sandblasted, cleaned and dried. Specifically, alcohol or acetone is used to thoroughly clean or wipe the surface of the parts. If there is oil in the weld, it needs to be heated and baked, and blown clean with compressed air. Brown corundum is used to repeatedly sandblast the substrate surface. The sand particle size is not greater than 20 mesh, the sandblasting distance is 200mm~400mm, the sandblasting angle is 60°~75°, and the sandblasting material shall not be reused more than twice. The surface roughness after sandblasting should reach Sa2~Sa2.5. After sandblasting, use dry, oil-free compressed air to blow the surface of the workpiece clean. The interval time between sandblasting and spraying shall not exceed 2 hours, otherwise it needs to be sandblasted again;

[0060] SSS3, adopts supersonic flame spraying process for spraying, the flame spraying speed is greater than 3000m / s, the compressed air is dry, oil-free and clean, the compressed air pressure is 0.2Mpa~0.4Mpa, during spraying, the temperature of the substrate does not exceed 120℃, the interlayer temperature does not exceed 150℃, the thickness of each coating is not more than 10μm, powder feeding method: vertical powder feeding, powder feeding amount: 100g / min, argon pressure: 0.6MPa / min~0.8MPa / min, argon flow: 6L / min~8L / min , kerosene pressure: 1.5MPa / h~1.6MPa / h, kerosene flow: 0.4L / min~0.5L / min, oxygen pressure: 1.5MPa / h~1.7MPa / h, oxygen flow: 900L / min~920L / min, spraying current: 500A-520A, spraying voltage: 70V~72V, spraying distance: 320mm~350mm, spray gun moving speed: 280mm / s~300mm / s, the spraying process should be continuous spraying, and the interruption time should not exceed 2 hours;

[0061] After spraying, the parts are tested for bonding strength, microhardness and yield toughness. It is worth mentioning that bonding strength is one of the important indicators for evaluating the quality of thermal spray coatings, which refers to the bonding force between the coating and the substrate. The determination standards for bonding strength are currently divided into two types: national standards and civil aviation industry standards. The present invention adopts the national standard GB / T8642-2002 "Determination of tensile bonding strength of thermal spraying" for determination. The specific process is as follows: a carbon steel sample with the same material as the part is selected, bonded with E7 glue or FM1000, and a tester conforming to GB / T 16825 and any type of tensile testing machine that can meet the static loading conditions, record the force value during stretching, and calculate the bonding strength; the toughness of the coating usually refers to the ability of the coating to resist crack propagation, which is an important performance indicator for measuring the performance of the coating under mechanical stress and impact. A coating with high toughness can better absorb energy and resist the formation and diffusion of cracks, thereby improving the overall durability and reliability of the coating. The present invention adopts the Chinese standard GB / T10419-2002 "Determination of impact toughness of tungsten carbide steel bonded cemented carbide". Specifically, the impact absorption energy (Ak) represents the energy absorbed by the sample when it is broken under the impact test force once, and the impact toughness (ak) represents the impact absorption energy per unit cross-sectional area of ​​the sample at the fracture point under impact. The standard conforming to GB / T The impact energy of 3808 is 30J pendulum impact tester. In the test, the sample is fixed on the support of the tester, and then the hammer is used to hit the sample at a standardized speed and energy. The measurement result is the energy absorbed by the sample before it breaks during the impact. The microhardness of the coating refers to the ability of the coating material to resist local deformation at a microscopic scale, which mainly reflects the mechanical strength and wear resistance of the coating. The Chinese standard GB / T 8640-1988 "Rockwell Hardness Test Method for Metal Thermal Spray Coating Surface" is adopted to measure the microhardness of 6 points on the surface of the sample coating at random and calculate the average value.

[0062] According to the above-mentioned coating performance detection steps, a ZG0Cr13Ni4Mo martensitic stainless steel cuboid is selected as the spraying substrate, with a size of 20cm×10cm×3cm and a coating thickness of about 0.4mm. Under the same spraying conditions, the data comparison between WC-Ni and WC-AlCoCrFeNiMn in microhardness, bonding strength and impact absorption energy is listed. It should be pointed out that in order to reduce the error of the measurement data, three samples A1, A2, and A3 are selected in WC-Ni, collectively referred to as sample A, and the content of WC in sample A is 86%, and the content of Ni is 14%. In WC-AlCoCrFeNiMn, three samples B1, B2, and B3 are selected, collectively referred to as sample B, and the content of WC in sample B is 86%, and the content of AlCoCrFeNiMn is 14%:

[0063]

[0064] Table 1

[0065] According to Table 1, the average microhardness of sample A is 1587HV0.3, the average bonding strength is about 71.7MPa, and the average impact energy is about 1.23J; the average microhardness of sample B is about 1583HV0.3, the average bonding strength is about 77.6MPa, and the average impact energy is about 1.55J. Based on the above data, the microhardness of sample B coating is slightly lower than that of sample A, and the difference between the two values ​​is not large, but the bonding strength of sample B is about 8.3% higher than that of sample A, and the impact energy of sample B is about 26% higher than that of sample A. It can be seen that compared with the single principal alloy as a bond in the prior art, AlCoCrFeNiMn has an improvement effect on the impact toughness of the coating and the bonding strength between the coating and the substrate when the hardness of the coating changes less;

[0066] In the prior art, although WC coating has high hardness and strong wear resistance, it is usually brittle, especially in thicker or complex-shaped coatings, and is prone to cracks and fractures. This is because a single or low-complexity metal binder such as Co or Ni may not be sufficient to resist high impact or high deformation application environments while providing sufficient bonding force. The addition of AlCoCrFeNiMn can improve the overall toughness and fracture resistance of the coating through its inherent multi-element uniform distribution characteristics. By crack deflection, bridging and improving plastic deformation ability, when the crack encounters a phase boundary of different hardness or modulus during propagation, its propagation path will change. High entropy alloys help absorb impact energy and slow crack propagation. This increased toughness is particularly important for applications under dynamic load or impact load conditions.

[0067] In the prior art, there is a certain difference in the thermal expansion coefficients of WC and Ni, which may lead to an increase in the thermal stress between the coating and the substrate under cyclic heat load conditions, thereby affecting the bonding stability of the coating. The thermal expansion coefficient of the AlCoCrFeNiMn high-entropy alloy can be optimized through alloy design to better match the substrate material, thereby possibly improving the thermal compatibility between the coating and the substrate and reducing the stress and debonding problems caused by thermal expansion mismatch. In addition, the AlCoCrFeNiMn multi-principal alloy has good wettability with WC and can form a strong bonding interface.

[0068] According to the above spraying performance testing steps, a ZG0Cr13Ni4Mo martensitic stainless steel cuboid was selected as the spraying substrate, with a size of 20cm×10cm×3cm and a coating thickness of about 0.4mm. Under the same spraying conditions, three samples were selected, collectively referred to as sample C, wherein the content of WC in sample C1 was 86%, the content of AlCoCrFeNiMn was 10%, and the total content of Y and Ti was 4%; the content of WC in sample C2 was 86%, the content of AlCoCrFeNiMn was 12%, and the total content of Y and Ti was 2%; the content of WC in sample C3 was 86%, the content of AlCoCrFeNiMn was 8%, and the total content of Y and Ti was 6%. The following is a table of microhardness, bonding strength and impact absorption of sample B and sample C:

[0069]

[0070] Table 2

[0071] It can be concluded from Table 2 that the microhardness of samples C1, C2 and C3 are slightly lower than that of samples A1 and B1, and the microhardness of these samples is not much different. Secondly, for the bonding strength, taking sample C1 as an example, the bonding strength of samples C1 and B1 is greater than the measured value at the time of glue breaking, that is, the specific bonding strength values ​​of samples C1 and B1 are difficult to compare, but the bonding strength of samples C1 and B1 is greater than that of sample A1, and the impact energy of sample B1 is 28.5% higher than that of sample A1, and the impact energy of sample C1 is 31.7% higher than that of sample A1. Based on the data, the impact toughness of the coating with Y and Ti rare earth element powder added will be better than the impact toughness of the coating without the rare earth element. In summary, compared with the single main alloy as a bonding agent in the prior art, AlCoCrFeNiMn, Y and Ti have an improvement effect on the bonding strength and impact toughness between the coating and the substrate, and the performance will also be different due to the different contents of AlCoCrFeNiMn, Y and Ti in the coating;

[0072] The addition of Y and Ti elements can improve the bonding strength between the coating and the substrate. These elements can promote the diffusion reaction between the coating material and the substrate material, form a tighter interface bonding, reduce defects and cracks on the interface, thereby improving the bonding strength. Secondly, it can improve the toughness of the coating. These elements can promote the grain refinement and grain boundary strengthening of the coating, so that the coating has better plastic deformation ability and crack propagation resistance, thereby improving the overall toughness of the coating.

[0073] Based on Table 1 and Table 2 and combined with the properties of AlCoCrFeNiMn and Y and Ti elements, it can be concluded that adding AlCoCrFeNiMn and Y and Ti elements to WC can enhance the oxidation resistance and cavitation resistance of the coating, making the coating more suitable for working in harsh environments, improving the toughness of the coating, increasing the service life and reliability of the coating, improving the thermal conductivity and thermal expansion coefficient of the coating, improving the bonding performance between the coating and the substrate, reducing peeling and shedding phenomena, and improving the reliability and stability of the coating, so that the formulation can be used in scenarios requiring both high wear resistance and high toughness.

[0074] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A coating formulation based on tungsten carbide, characterized in that: The invention comprises hard particle material, binder, additive and solvent, wherein the content of hard particle material is 80% to 85%, the content of binder is 5% to 10%, the content of additive is 3% to 5%, the content of solvent is 5% to 8%, and the hard particle material comprises the following components: WC powder as the wear-resistant main body: WC powder content is 85% to 88%; High entropy alloy powder as a bonding phase: the content of high entropy alloy powder is 8% to 10%; Rare earth element powder for modulation: the content of rare earth element powder is 2% to 5%.

2. A tungsten carbide-based coating formulation according to claim 1, characterized in that: The high entropy alloy powder is AlCoCrFeNiMn. Calculated based on the total weight of AlCoCrFeNiMn itself as 100%, the content of Co is 50% to 60%, the content of Cr is 25% to 30%, the content of Al is 5% to 8%, the content of Fe is 5% to 8%, the content of Mn is 2% to 5%, and the balance is Ni.

3. A coating formulation based on tungsten carbide according to claim 1, characterized in that: The rare earth element powder includes Y and Ti. Taking the total weight of the rare earth element powder as 100%, the content of Y is 30% to 50%, and the content of Ti is 50% to 70%.

4. A tungsten carbide-based coating formulation according to claim 1, characterized in that: The component of the adhesive is epoxy resin, the component of the additive is antioxidant or anti-ultraviolet agent, and the solvent is ethanol.

5. A tungsten carbide-based coating formulation according to claim 2, characterized in that: AlCoCrFeNiMn powder was prepared by gas atomization method. The following steps are involved: S1, pouring AlCoCrFeNiMn powder raw materials into a crucible according to proportion, and melting the AlCoCrFeNiMn raw materials by induction heating to obtain AlCoCrFeNiMn alloy liquid; S2, the AlCoCrFeNiMn alloy liquid is crushed by a tightly coupled atomization method to form alloy powder, the atomization medium is argon gas, and the atomization pressure is 3MPa~4MPa.

6. A process for producing a coating formulation based on tungsten carbide according to any one of claims 1 to 5, characterized in that: The production process includes the following steps: SS1, mixing: adding the hard particle material, binder, additive and solvent into a stirring device according to a proportion, stirring at a speed of 100 r / min to 200 r / min, and mixing for 40 min to 60 min to obtain a mixed material; SS2, drying: the mixed material is placed in a centrifugal spray dryer, the inlet air temperature of the spray drying is 150°C to 180°C, the outlet air temperature is 90°C to 140°C, the medium is nitrogen, the rotation frequency is 40Hz to 50Hz, the atomizing disk speed is 8000r / min to 10000r / min, the feed amount is 200mL / min to 400mL / min, and agglomerated particles are obtained after atomization drying; SS3, debinding and sintering: The agglomerated particles are treated by debinding and sintering process to obtain a solidified material. SS4, ball milling: add the solidified material into the ball mill for 6h to 8h, and obtain the spray powder after ball milling. The particle size of the spray powder is 8μm to 12μm.

7. The production process of the coating formulation based on tungsten carbide according to claim 6, characterized in that: In step SS3, the debinding stage in the debinding sintering process includes the following steps: SS301, heating stage: put the agglomerated particles in a hot degreasing furnace and heat them gradually to 200℃~400℃; SS302, insulation stage: the agglomerated particles are kept at a temperature of 200°C to 400°C for 5h to 7h.

8. The production process of the coating formulation based on tungsten carbide according to claim 6, characterized in that: In step SS3, the sintering stage in the debinding sintering process is divided into: SS311, heating stage: using a high-temperature sintering furnace with precise temperature control and atmosphere control functions, slowly heat the degreased agglomerated particles to the sintering temperature, the sintering temperature is 1100°C to 1500°C, the sintering time is 5h to 7h, and product 1 is obtained; SS312, cooling stage: slowly cool the product to room temperature to finally obtain a solidified material.

9. The spraying process of the coating based on tungsten carbide according to any one of claims 1 to 5, characterized in that: The following steps are involved: SSS1, before spraying, the spray powder is dried in a drying oven for 30min to 60min, and the drying temperature is maintained at 90℃ to 120℃; SSS2, sandblasting, cleaning and drying of the substrate to be sprayed; SSS3, adopts supersonic flame spraying process for spraying, the flame spray speed is greater than 3000m / s, the compressed air is dry, oil-free and clean, the pressure of compressed air is 0.2Mpa~0.4Mpa, during spraying, the temperature of the substrate does not exceed 100℃, the interlayer temperature does not exceed 150℃, and the thickness of each coating is not more than 10μm.

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