WO2023236728A1 - Wear-resistant blade, and preparation method therefor and use thereof - Google Patents

Abstract

The present invention provides a wear-resistant blade for a turbodrill, and a preparation method therefor and the use thereof, and relates to the technical field of deep geological drilling. The wear-resistant blade specifically comprises a blade substrate 1, an Al_xCoCrFeNi high-entropy alloy coating 2, which has a multi-layer structure and is located on the surface of the substrate, and a regulating layer 3, which is arranged between any two adjacent layers of the Al_xCoCrFeNi high-entropy alloy coatings, wherein x ranges from 0 to 2. In the present invention, a gradient coating is prepared by sequentially preparing an Al_xCoCrFeNi high-entropy alloy coating by means of increasing the atomic percentage of Al, and then alternatively compounding same with an Ni-P/Al₂O₃ regulating layer, such that the binding capacity of the high-entropy alloy coating to the blade substrate is enhanced; and by subjecting the high-entropy alloy coating to a vacuum heat treatment, the structure compactness and hardness of the coating and the binding force between the coatings are improved, and thus the comprehensive wear resistance of a blade of a turbodrill is greatly improved. The wear-resistant blade provided in the solution of the present invention has good mechanical strength and wear resistance, can be used as an operating blade for a turbodrill, and is applicable for various harsh working conditions of drilling.

Description

Wear-resistant blade and preparation method and application thereof Technical field

The invention belongs to the technical field of deep geological drilling, and specifically relates to a wear-resistant blade and its preparation method and application.

Background technique

The turbine is the power core of the turbine drilling tool, and the turbine blades, as the core components of the turbine drilling tool, play the role of energy conversion in the turbine system. For the turbine blades, which are key components of turbine drilling tools, cast steel materials are often used, and there are problems such as easy surface deformation and low strength. During the geological drilling process, turbine blades will inevitably undergo wear and tear from high-pressure drilling fluids, rock debris, etc., resulting in wear and failure, which will reduce the overall drilling efficiency.

One of the current ways to solve this problem is to use high-performance alloys or electrolytic machining to improve the wear resistance of turbine blades under harsh working conditions. However, this method is not only expensive but also has a mediocre performance improvement effect. Therefore, it is necessary to develop new methods to protect turbine blades and improve the wear resistance of the blade surface, thereby extending the service life of turbine blades and improving drilling efficiency.

Contents of the invention

The purpose of the present invention is _to provide a wear-resistant blade, which is prepared by alternately _{compounding Al} The technical solution of layer vacuum heat treatment can effectively enhance the comprehensive wear resistance of turbine drilling tool blades, thereby improving drilling efficiency, saving drilling costs, and improving economic benefits.

In order to achieve the above object, the present invention provides a wear-resistant blade, which includes a blade substrate 1, an _Al Adjustment _{layer 3 is provided between the Al x CoCrFeNi} high entropy alloy coatings; the atomic percentage of Al in each layer of the Al The range is 0~2.

In a preferred embodiment, the Al _x CoCrFeNi high-entropy alloy coating with a multi-layer structure is at least two layers;

From the blade substrate to the blade surface direction, any two adjacent layers of the Al _x CoCrFeNi high-entropy alloy The Al atomic percentage between coatings increases sequentially with a gradient of not less than 5%.

In a preferred embodiment, the adjustment layer is brush-plated Ni-P/Al ₂ O ₃ coating; the Ni-P/Al ₂ O ₃ coating includes nano-alumina; the nano-alumina particles Diameter is 20~30nm;

In a preferred embodiment, the total thickness of the Al _x CoCrFeNi high-entropy alloy coating with a multi-layer structure and the adjustment layer is 600 to 800 μm.

Another object of the present invention is to provide a method for preparing a wear-resistant blade by preparing multiple layers of Al _x CoCrFeNi high-entropy alloy coatings on the surface of the blade substrate to enhance the wear resistance of _the blade. An adjustment layer is set between the CoCrFeNi high-entropy alloy coatings to regulate surface roughness and bonding strength. Vacuum heat treatment of the high-entropy alloy coating can eliminate the residual stress inside the coating, reduce the void ratio, and create a better composite adjustment layer.

In order to achieve the above objectives, the present invention provides a method for preparing wear-resistant blades, which specifically includes the following steps:

S1 pre-treats the blade substrate;

S2 uses thermal spraying to prepare a layer of Al _x CoCrFeNi high-entropy alloy coating with high-entropy alloy powder;

S3 performs vacuum heat treatment on the high-entropy alloy coating obtained in step S2;

S4 prepare an adjustment layer on the surface of the high-entropy alloy coating treated in step S3;

S5 sequentially cycles on the surface of the adjustment layer obtained in step S4: thermal spraying the high-entropy alloy coating using the method of step S2, vacuum heat treatment of the high-entropy alloy coating using the method of step S3, and preparing the adjustment layer using the method of step S4; wherein, The number of cycles of step S2 and step S3 is m times, and the number of cycles of step S4 is m-1 times; 2≤m≤4;

S6 grinds and polishes the outermost Al _x CoCrFeNi high-entropy alloy coating after vacuum heat treatment to obtain a wear-resistant blade with multiple layers of high-entropy alloy coating.

In a preferred embodiment, in step S1, the pretreatment includes grinding, surface cleaning and roughening.

In a preferred embodiment, in step S2, the specific operating steps of thermal spraying are: using Supersonic flame spray technology uses hydrogen as fuel, oxygen as combustion-supporting gas, and nitrogen as powder-feeding carrier gas;

The hydrogen flow rate is 400～800slpm; the oxygen flow rate is 100～300slpm; the nitrogen flow rate is 20～40slpm; the spraying distance is 200～300mm;

The spraying angle is 60°~90°; the powder feeding rate is 10~50g/min.

In a preferred embodiment, in step S3, the specific steps of the vacuum heat treatment are:

S31 pre-treatment: air tightness inspection and sample cleaning of vacuum heat treatment equipment;

S32 Vacuuming: Place the sample into the vacuum heat treatment equipment, seal and evacuate;

S33 heating stage: turn on the circulating water in the furnace body to keep the furnace wall at room temperature; when the vacuum degree is less than 2×10 ^-4 Pa, adjust the preset temperature to 50°C, turn on the heating switch, and then increase it sequentially in units of 50°C Preset temperature until the temperature in the furnace rises to 400~600℃;

S34 heat preservation stage: the heat preservation stage lasts 2 to 4 hours;

S35 cooling stage: Turn off the vacuum heat treatment equipment and wait until the sample cools to room temperature before proceeding with subsequent operations.

In a preferred embodiment, in step S4, the specific steps for preparing the adjustment layer are: Ni-P/Al ₂ O ₃ coating prepared by brush plating. During the brush plating process, the net voltage is 12~ 16V; brush plating base layer voltage is 14~18V; brush plating Ni-P/Al ₂ O ₃ adjustment layer preparation process conditions are positive connection, voltage 6~10V, time 2~4 hours.

Another object of the present invention is to provide the application of the above-mentioned wear-resistant blade or the wear-resistant blade prepared by any of the above-mentioned methods. The wear-resistant blades provided by the solution of the present invention have excellent mechanical strength and wear resistance, and can be widely used in turbine drilling tools as device blades.

In a preferred embodiment, the wear-resistant blades serve as turbine drill blades.

Compared with the existing technology, the technical solution of the present invention has the following advantages:

1. When the blades of turbine drilling tools are drilled in deep areas, wear and failure will inevitably occur. One way to solve this problem now is to use high-performance alloys or electrolytic machining to improve the performance of turbine blades in harsh processes. Wear resistance under normal conditions, but using this method is not only expensive but also has a mediocre performance improvement effect. Compared with the existing technology, the present invention adopts the method _of sequentially increasing the _Al atomic percentage to prepare _Al The bonding ability between the coating and the blade matrix; through vacuum heat treatment of the high-entropy alloy coating, the structural density, hardness and bonding force between coatings are improved, thereby greatly enhancing the comprehensive wear resistance of the turbine drilling tool blades.

2. Multi-layer Al _x CoCrFeNi high-entropy alloy coatings with different Al atomic percentages increase in order from low to high from the blade base to the blade surface. The coatings close to the blade base have higher Al atomic percentages. _The low Al It has a larger atomic radius and is a BCC phase forming element. As the Al content increases, the high-entropy alloy coating gradually transforms from the FCC phase to the BCC phase. The hardness of the BCC phase is higher than that of the FCC phase, so the outer coating is The Al _x CoCrFeNi high-entropy alloy coating with a higher Al atomic percentage makes the coating have higher hardness and wear resistance, which can greatly reduce the wear of the blade under actual working conditions. Therefore, multi-layer Al _x CoCrFeNi high-entropy alloy coatings with different Al atomic percentages can be used to protect turbine drilling tool blades and effectively extend the service life of the blades.

3. The use of supersonic flame spraying technology has high controllability, and can repeatedly spray the turbine blades, making it easy to implement large-scale industrial production applications, thereby improving drilling efficiency, saving drilling costs, and improving economic benefits. Supersonic flame spraying technology will cause the coating to have pores (2% to 4%) and high surface roughness (15 to 25 μm). Since the application of the present invention is a multi-layer coating structure prepared in batches, if it is directly applied on Spraying a layer with a lower Al atomic ratio on the surface and a layer with a higher Al atomic ratio will cause problems such as low density and poor bonding strength due to excessive roughness. Therefore, brush plating after spraying Ni-P can fill the pores of the coating, reduce surface roughness, and enhance the bonding between coatings. The addition of Al ₂ O ₃ is beneficial to improving the density and uniformity of the Ni-P coating structure and promoting crystal nucleation.

4. Vacuum heat treatment can eliminate the residual stress inside the spray coating and reduce the porosity; but when the coating is too thick, only one vacuum heat treatment will cause the internal stress of the coating to be unable to be fully released, resulting in cracks or coating peeling. Therefore Each time a high-entropy alloy coating is prepared, a vacuum heat treatment is performed. Treatment can effectively eliminate coating residual stress, reduce porosity, and enhance the toughness of the overall coating. In addition, vacuum heat treatment at a certain temperature (400-600°C) will promote the formation of the BCC phase, and the BCC phase often has higher hardness. Therefore, the hardness and wear resistance of the high-entropy alloy coating will also be improved. When the vacuum heat treatment temperature is lower than 400°C, the structure and mechanical properties of the high-entropy alloy coating do not change significantly, and have little effect on the toughness and wear resistance of the coating. When the temperature exceeds 600°C, the high-entropy alloy coating will undergo deformation. The transition from the BCC phase to the FCC phase, the hardness value of the FCC phase is lower than that of the BCC phase, resulting in a decrease in the hardness and wear resistance of the coating.

5. The preparation method of the present invention is simple and reasonable, can effectively improve the mechanical properties of the blade, control the processing cost, and is easy to produce and prepare. The prepared wear-resistant blades have a wide range of applications and can be used as working blades for turbine drilling tools and are suitable for various harsh working conditions. Its excellent wear resistance can significantly reduce operating costs and reduce blade loss and replacement.

Description of the drawings

These and/or other aspects and advantages of the present invention will become clearer and easier to understand from the following detailed description of embodiments of the present invention in conjunction with the accompanying drawings, in which:

Figure 1 is a schematic cross-sectional structural diagram of a wear-resistant blade provided by the present invention;

Figure 2 shows the microhardness of the wear-resistant blade provided in Embodiment 1 of the present invention;

Figure 3 shows the wear rate of the wear-resistant blade provided in Embodiment 1 of the present invention.

Explanation of main reference signs: 1-blade substrate, 2-Al _x CoCrFeNi high-entropy alloy coating, 3-adjusting layer.

Detailed ways

In order to enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below in conjunction with the drawings and specific embodiments. However, it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

Embodiments of the present invention provide a wear-resistant blade to solve the problems in the prior art that the blades are easy to wear and have poor mechanical strength.

The technical solution in the present invention is to solve the above problems, and the general idea is as follows:

1 , the purpose of the present invention is to provide a wear-resistant blade, which includes a blade substrate 1, an Al _x CoCrFeNi high-entropy alloy coating 2 with a multi-layer structure located on the surface of the substrate, and two adjacent layers in any The adjustment layer ₃ is provided between the Al _x CoCrFeNi high-entropy alloy coatings; the atomic percentage content of Al in each layer of the Al The range of x is 0~2. If the value of x is too large, the brittleness of the high-entropy alloy coating increases and the toughness decreases, so x is set in the range of 0-2.

In a preferred embodiment, the blade substrate can be made of a substrate material well known to those skilled in the art. For example, 35CrMo steel can be used as the blade substrate.

In a preferred embodiment, the atomic percentage of Al in the first high-entropy alloy coating connected to the blade substrate can be 0% or any value less than 33%, as long as the first The atomic percentage of Al in the first layer of high-entropy alloy coating and the subsequent high-entropy alloy coating can be increased sequentially; more preferably, the atomic percentage of Al in the first layer of high-entropy alloy coating connected to the blade substrate is The atomic percentage contents are 0%, 3% or 6% respectively; the corresponding atomic percentage contents of CoCrFeNi are 100%, 97% or 94% respectively.

In a preferred embodiment, the atomic percentage of Al in the high-entropy alloy coating on the outermost surface of the wear-resistant blade is not higher than 33%.

In a preferred embodiment, the Al _x CoCrFeNi high-entropy alloy coating with a multi-layer structure is at least two layers.

In a preferred embodiment, the thickness of each Al _x CoCrFeNi high-entropy alloy coating is 200 to 300 μm.

In a preferred embodiment, the porosity of each layer of the Al _x CoCrFeNi high-entropy alloy coating is 2% to 4%, and the surface roughness is 15 to 25 μm.

In a preferred embodiment, from the blade base to the blade surface, the Al atomic percentage between any two adjacent layers of the Al _x CoCrFeNi high-entropy alloy coatings increases sequentially with a gradient of not less than 5%. If the gradient is set to less than 5%, the hardness and wear resistance of the material will not be significantly improved.

In a preferred embodiment, the adjustment layer is an electric brush plating Ni-P/Al ₂ O ₃ coating; the composition of the Ni-P/Al ₂ O ₃ coating includes an electric brush plating solution and nano-oxide Aluminum; among them, the components of the brush plating solution Including NiSO ₄ .7H ₂ O 20～40g/L, Na ₂ SO ₄ 2～4g/L, NaH ₂ PO ₂ .H ₂ O 6～8g/L, CH ₃ COOH 1.8～2.8g/L, C ₆ H ₈ O ₇ 4.0~5.0g/L, sodium dodecylbenzene sulfonate 0.05~0.10g/L and thiourea 0.02~0.04g/L; the particle size of the nano-alumina is 20~30nm, and the concentration is 10~ 40g/L.

In a preferred embodiment, the thickness of the adjustment layer does not exceed the roughness of each Al _x CoCrFeNi high-entropy alloy coating, that is, the thickness of the adjustment layer is 15 to 25 μm. The purpose of the adjustment layer is first to reduce the surface roughness of the coating, and secondly to make the surface of the coating smoother and the roughness value more uniform. If the thickness of the adjustment layer is too thick, the high-entropy alloy coating will be completely covered. If the surface roughness of the brush plating layer is too low, the bonding strength will decrease during subsequent spraying. Therefore, the thickness of the adjustment layer is set to 15 to 25 μm.

In a preferred embodiment, the total thickness of the Al _x CoCrFeNi high-entropy alloy coating with a multi-layer structure and the adjustment layer is 600 to 800 μm. If the total thickness is less than 600 μm, it is difficult to meet the multi-layer structure. If the total thickness is greater than 800 μm, the residual stress will be too large and the bonding force between coatings will be reduced.

Another object of the present invention is to provide a method for preparing wear-resistant blades, which specifically includes the following steps:

S1 pre-treats the blade substrate;

S2 uses thermal spraying to prepare a layer of Al _x CoCrFeNi high-entropy alloy coating with high-entropy alloy powder;

S3 performs vacuum heat treatment on the high-entropy alloy coating obtained in step S2;

S4 prepare an adjustment layer on the surface of the high-entropy alloy coating treated in step S3;

S5 sequentially cycles on the surface of the adjustment layer obtained in step S4: thermal spraying the high-entropy alloy coating using the method of step S2, vacuum heat treatment of the high-entropy alloy coating using the method of step S3, and preparing the adjustment layer using the method of step S4; wherein, The number of cycles of step S2 and step S3 is m times, and the number of cycles of step S4 is m-1 times; 2≤m≤4;

S6 grinds and polishes the outermost Al _x CoCrFeNi high-entropy alloy coating after vacuum heat treatment to obtain a wear-resistant blade with multiple layers of high-entropy alloy coating.

In a preferred embodiment, in step S1, the pretreatment includes grinding, surface cleaning and roughening. More preferably, the polishing treatment is carried out by sand grinding for 5-10 minutes, with the purpose of making the roughness of the coating surface relatively uniform to prepare for the next step of sand blasting; the surface cleaning is performed with absolute ethanol. Cleaning agent is used for cleaning in an ultrasonic cleaner for 5-10 minutes. The purpose is to remove oxidation, oil and rust; the roughening treatment is sandblasting; the sandblasting and roughening uses emery; the particle size of the emery is 400-800 μm; blasting The sand pressure is 0.1~0.3MPa; the sandblasting time is 20~40s; the sandblasting distance is 20~40mm. The purpose is to make the blade substrate have a certain roughness (5~10μm) and enhance the bonding strength between the coating and the substrate.

In a preferred embodiment, in step S2, the specific operating steps of the thermal spraying are: using supersonic flame spraying technology, using hydrogen as fuel, oxygen as combustion-supporting gas, and nitrogen as powder-feeding carrier gas; the hydrogen flow rate is 400~ 800slpm; oxygen flow rate is 100～300slpm; nitrogen flow rate is 20～40slpm; spraying distance is 200～300mm; spraying angle is 60°～90°; powder feeding rate is 10～50g/min. In this step, if the powder feed rate is too low, the coating deposition rate will be slow, which will increase production costs; if the powder feed rate is too high, it will easily cause the spray nozzle to clog and damage the spray equipment.

In a preferred embodiment, in step S2, the preparation method of the high-entropy alloy powder is a vacuum atomization method; specifically, it includes the following steps: using vacuum melting and high-pressure gas atomization powdering technology, pure aluminum with different atomic ratios is Pure metal ingots of pure cobalt, pure chromium, pure iron and pure nickel are put into the crucible of the smelting chamber for smelting. Before starting smelting, the smelting chamber and atomization chamber are evacuated respectively. Heating temperature to 1400-1500℃ (the melting point of the high-entropy alloy changes slightly depending on the Al content) to completely melt the metal ingot. Then the molten metal in the crucible is poured into the tundish. The molten metal flows out from the nozzle under the tundish and is impacted by high-speed high-purity argon gas to form small droplets. The metal droplets are cooled in the cooling chamber to form solid particles and are Collect into powder collection tank. The high-speed, high-purity argon gas pressure is 6-8MPa, and the leak diameter is φ4-6mm. The protective gas and atomized medium gas used in the pulverizing process are both high-purity argon (purity 99.99%). The particle size of the prepared high-entropy alloy raw material powder is 15-45 μm.

In a preferred embodiment, in step S3, the specific steps of the vacuum heat treatment are:

S31 pre-treatment: Carry out air tightness inspection and sample cleaning of the vacuum heat treatment equipment; sample cleaning involves ultrasonicizing the blades sprayed with high-entropy alloy coating with alcohol for 5-10 minutes;

S32 Vacuuming: Place the sample into the vacuum heat treatment equipment, seal and evacuate to the vacuum level in the furnace Less than 2×10 ^-4 Pa;

S33 heating stage: turn on the circulating water in the furnace body to keep the furnace wall at room temperature; when the vacuum degree is less than 2×10 ^-4 Pa, adjust the preset temperature to 50°C, turn on the heating switch, and then increase it sequentially in units of 50°C Preset temperature until the temperature in the furnace rises to 400~600℃;

S34 heat preservation stage: the heat preservation stage lasts 2 to 4 hours;

S35 cooling stage: Turn off the vacuum heat treatment equipment and wait until the sample cools to room temperature before proceeding with subsequent operations.

In a preferred embodiment, in step S4, the specific steps for preparing the adjustment layer are: Ni-P/Al ₂ O ₃ coating prepared by brush plating. During the brush plating process, the net voltage is 12~ 16V; brush plating base layer voltage is 14~18V; brush plating Ni-P/Al ₂ O ₃ adjustment layer preparation process conditions are positive connection, voltage 6~10V, time 2~4 hours.

In a preferred embodiment, after each step S2 is processed, the prepared Al _x CoCrFeNi high-entropy alloy coating has a porosity of 2% to 4% and a surface roughness of 15 to 25 μm; After step S2, step S3 and step S4, the surface roughness of the adjustment layer on the surface of the Al _x CoCrFeNi high-entropy alloy coating is 5 to 10 μm. It can be seen that the surface roughness decreases after adding the adjustment layer. And this roughness value is beneficial to the subsequent processing of thermal spraying high-entropy alloy coating.

In a preferred embodiment, the grinding and polishing process can be performed by any device and method known to those skilled in the art. A more preferred grinding and polishing method is: using metallographic sandpaper to perform 200, 400, 800, 1200, Polish with 1500 and 2000 mesh, and use velvet polishing cloth and diamond polishing fluid for polishing.

Another object of the present invention is to provide the application of the above-mentioned wear-resistant blade or the wear-resistant blade prepared by any of the above-mentioned methods. The wear-resistant blades provided by the solution of the present invention have excellent mechanical strength and wear resistance, and can be widely used in turbine drilling tools as device blades.

The specific structures _of the following embodiments are the same. The wear-resistant blades include a blade base and a multi-layer Al _x CoCrFeNi high-entropy alloy coating located on the surface of the base; each layer of the Al The atomic percentage of Al in the coating gradually increases, and the range of x is 0 to 2; there is a device between any two layers of the _Al It not only ensures the wear resistance of turbine blades by increasing the percentage of Al atoms, but also significantly improves the bonding strength between the Al _x CoCrFeNi high-entropy coating and the blade matrix through the CoCrFeNi-based high-entropy alloy coating. A Ni-P/Al ₂ O ₃ adjustment layer is used to reduce surface roughness and improve bonding strength, and layer-by-layer vacuum heat treatment is used to fully release the internal stress of the coating, better improve the overall performance of the coating, and greatly enhance the turbine drilling tool blades. comprehensive wear resistance.

The technical solutions of the present application are described in detail below through specific examples:

Unless otherwise specified, the technical means used in the present invention are conventional means well known to those skilled in the art. The various raw materials, reagents, instruments and equipment used in the present invention can be purchased in the market or can be prepared by existing methods. get. The room temperature mentioned in the present invention is 25°C.

Example 1

The atomic percentage content of Al in the first layer of high-entropy alloy coating from the blade substrate to the surface direction is 0%; the atomic percentage content of CoCrFeNi is 100%.

The thickness of each Al _x CoCrFeNi high-entropy alloy coating is approximately 300 μm.

_The multi-layer structure of _the Al

The percentage of Al atoms between the two layers of Al _x CoCrFeNi high-entropy alloy coatings increases sequentially with a gradient of 20%;

There is an adjustment layer between the two layers of Al _x CoCrFeNi high-entropy alloy coatings for regulating surface roughness and bonding strength;

The adjustment layer is brush-plated Ni-P/Al ₂ O ₃ coating;

The components of the Ni-P/Al ₂ O ₃ adjustment layer include: brush plating solution and nano-alumina; the components of the brush plating solution are NiSO ₄ .7H ₂ O 20g/L, Na ₂ SO ₄ 2g/L , NaH ₂ PO ₂ .H ₂ O 6g/L, CH ₃ COOH 1.8g/L, C ₆ H ₈ O ₇ 4.0g/L, sodium dodecylbenzene sulfonate 0.05g/L, thiourea 0.02g/ L; the particle size of the nano-alumina is 20-30nm, and the concentration is 10g/L;

For the wear-resistant blade, the total thickness of the Al _x CoCrFeNi high-entropy alloy coating and the adjustment layer is approximately 600 μm.

The wear-resistant blade preparation method includes the following steps:

(1) Pretreat the blade substrate;

(2) A layer of Al _x CoCrFeNi high-entropy alloy coating is thermally sprayed on the blade surface obtained in the previous step;

(3) Perform vacuum heat treatment on the high-entropy alloy coating obtained in the previous step;

(4) Prepare an adjustment layer on the surface of the high-entropy alloy coating obtained in the previous step;

(5) Repeat steps (2) and (3) in sequence;

(6) The outermost Al _x CoCrFeNi high-entropy alloy coating is ground and polished to meet the accuracy requirements, that is, a two-layer high-entropy alloy coating is obtained on the blade base surface.

In the wear-resistant blade and its preparation method, the pretreatment includes surface grinding, surface cleaning and roughening. The grinding treatment is carried out by sand grinding; the surface cleaning includes deoxidation, oil removal, rust removal, and cleaning with absolute ethanol in an ultrasonic cleaner; the roughening treatment is sand blasting; the sand blasting and roughening adopts emery; emery The particle size is 400μm; the sandblasting pressure is 0.1MPa; the sandblasting time is 20s; the sandblasting distance is 20mm.

In the wear-resistant blade and its preparation method, thermal spraying adopts supersonic flame spraying technology, using hydrogen as fuel, oxygen as combustion-supporting gas, and nitrogen as powder-feeding carrier gas; the hydrogen flow rate is 400slpm; the oxygen flow rate is 100slpm; The nitrogen flow rate is 20slpm; the spraying distance is 200mm; the spraying angle is 60°; the powder feeding rate is 10g/min.

In the wear-resistant blade and its preparation method, each layer of high-entropy alloy coating is subjected to a separate vacuum heat treatment after preparation. Includes the following steps:

(1) Pretreatment: Air tightness inspection and sample cleaning of vacuum heat treatment equipment;

(2) Vacuuming: Place the sample into the vacuum heat treatment equipment, seal and evacuate until the vacuum degree in the furnace is less than 2×10 ^-4 Pa;

(3) Heating stage: Turn on the circulating water in the furnace body to keep the furnace wall at room temperature; after the vacuum degree meets the requirements, use the step heating method to effectively prevent the coating from cracking and reducing the density caused by the coating heating rate being too fast. First, Set the preset temperature to 50℃, turn on the heating switch, and then use 50℃ as the unit. Bits increase the preset temperature in sequence until the temperature in the furnace rises to 400°C;

(4) Heat preservation stage: The heat preservation stage lasts for 2 hours;

(5) Cooling stage: Close the vacuum heat treatment equipment to ensure that the furnace circulating water is always running and cools with the furnace.

According to the wear-resistant blade and its preparation method, the net voltage during the brush plating process is 12V; the voltage of the brush plating base layer is 14V; and the brush plating Ni-P/Al ₂ O ₃ adjustment layer preparation process conditions For positive connection, the voltage is 6V and the time is 2 hours.

Effect example 1

The wear-resistant blades prepared in Example 1 were tested for performance, and the results are as follows:

1. Effect of heat treatment on microhardness of high-entropy alloy coating

A microhardness tester (MICEMET-6030, Buehler, USA) was used to test the micro-Vickers hardness of the wear-resistant blade provided in Example 1. The test load was 200g and the load holding time was 15s; the test results are shown in Figure 2 It shows that the surface Vickers hardness of the high-entropy alloy coating on the outermost layer of the wear-resistant blade obtained in Example 1 of the present invention is 748HV0.2, which is higher than the blade substrate hardness (278HV0.2). A microhardness test was conducted on the outermost high-entropy alloy coating that had not undergone vacuum heat treatment. The microhardness was 532HV0.2. Compared with the outermost coating without vacuum heat treatment, the hardness of the coating is further improved after vacuum heat treatment.

2. Coating friction and wear performance test

The UMT multifunctional wear testing machine (UMT-TriboLab, CETR Company, USA) was used to test the tribological properties, and the linear sliding module was selected as the fixture. In the friction and wear test, a Si3N4 ball with a diameter of 6 mm was used as the counter grinding ball, and the wear mark length was 5 mm. The sliding frequency is 4Hz, the wear time is 20min, and the normal load is 5N respectively.

Wear rate refers to the volume worn under unit load within unit length. It reflects the volume of the coating sample worn during the friction and wear test and the friction process with the grinding ball. The size of the wear rate also reflects the wear performance of the material from the side. The smaller the wear rate, the better the wear resistance of the material, and vice versa.

The test results are shown in Figure 3. The average wear rate of the high-entropy alloy coating with different Al atomic percentages in the multi-layer structure obtained by the embodiment of the present invention is 0.68*10 ^-4 mm ³ ·N ^-1 ·m ^-1 , significantly lower than the wear rate of the blade base (3.55*10 ^-4 mm ³ ·N ^-1 ·m ^-1 ). The outermost high-entropy alloy coating that has not undergone vacuum heat treatment was tested and its wear rate was 1.07*10 ^-4 mm ³ ·N ^-1 ·m ^-1 . Compared with the outermost coating without vacuum heat treatment, the coating wear rate is further improved. It shows that this technical solution can effectively delay the wear and failure of blades and increase the service life of blades under actual working conditions.

Example 2

The atomic percentage of Al in the first layer of high-entropy alloy coating from the blade substrate to the surface is 3%; the atomic percentage of CoCrFeNi is 97%.

The thickness of each Al _x CoCrFeNi high-entropy alloy coating is approximately 250 μm.

_The multi-layer structure of _the Al

The percentage of Al atoms between the three layers of Al _x CoCrFeNi high-entropy alloy coatings increases sequentially with a gradient of 10%;

There are two adjustment layers for regulating surface roughness and bonding strength between the three layers of Al _x CoCrFeNi high-entropy alloy coatings;

The adjustment layer is brush-plated Ni-P/Al ₂ O ₃ coating;

The components of the Ni-P/Al ₂ O ₃ adjustment layer include: brush plating solution and nano-alumina; the components of the brush plating solution are NiSO ₄ .7H ₂ O 30g/L, Na ₂ SO ₄ 3g/L , NaH ₂ PO ₂ .H ₂ O 7g/L, CH ₃ COOH 2.3g/L, C ₆ H ₈ O ₇ 4.5g/L, sodium dodecylbenzene sulfonate 0.07g/L, thiourea 0.03g/ L; the particle size of the nano-alumina is 20-30nm, and the concentration is 25g/L;

For the wear-resistant blade, the total thickness of the Al _x CoCrFeNi high-entropy alloy coating and the adjustment layer is approximately 750 μm.

The wear-resistant blade preparation method includes the following steps:

(1) Pretreat the blade substrate;

(2) A layer of Al _x CoCrFeNi high-entropy alloy coating is thermally sprayed on the blade surface obtained in the previous step;

(3) Perform vacuum heat treatment on the high-entropy alloy coating obtained in the previous step;

(4) Prepare an adjustment layer on the surface of the high-entropy alloy coating obtained in the previous step;

(5) Repeat steps (2), step (3), step (4), step (2) and step (3);

(6) The outermost layer of AlCoCrFeNi high-entropy alloy coating is ground and polished to meet the accuracy requirements, that is, a three-layer structure of high-entropy alloy coating is obtained on the surface of the blade base.

In the wear-resistant blade and its preparation method, the pretreatment includes surface grinding, surface cleaning and roughening. The grinding treatment is carried out by sand grinding; the surface cleaning includes deoxidation, oil removal, rust removal, and cleaning with absolute ethanol in an ultrasonic cleaner; the roughening treatment is sand blasting; the sand blasting and roughening adopts emery; emery The particle size is 600μm; the sandblasting pressure is 0.2MPa; the sandblasting time is 30s; the sandblasting distance is 30mm.

In the wear-resistant blade and its preparation method, thermal spraying adopts supersonic flame spraying technology, using hydrogen as fuel, oxygen as combustion-supporting gas, and nitrogen as powder-feeding carrier gas; the hydrogen flow rate is 600slpm; the oxygen flow rate is 200slpm; The nitrogen flow rate is 30slpm; the spraying distance is 250mm; the spraying angle is 75°; the powder feeding rate is 30g/min.

In the wear-resistant blade and its preparation method, each layer of high-entropy alloy coating is subjected to a separate vacuum heat treatment after preparation. Includes the following steps:

(1) Pretreatment: Air tightness inspection and sample cleaning of vacuum heat treatment equipment;

(2) Vacuuming: Place the sample into the vacuum heat treatment equipment, seal and evacuate until the vacuum degree in the furnace is less than 2×10 ^-4 Pa;

(3) Heating stage: Turn on the circulating water in the furnace body to keep the furnace wall at room temperature; after the vacuum degree meets the requirements, use the step heating method to effectively prevent the coating from cracking and reducing the density caused by the coating heating rate being too fast. First, Set the preset temperature to 50℃, turn on the heating switch, and then increase the preset temperature in steps of 50℃ until the temperature in the furnace rises to 500℃;

(4) Heat preservation stage: The heat preservation stage lasts for 3 hours;

(5) Cooling stage: Close the vacuum heat treatment equipment to ensure that the furnace circulating water is always running and cools with the furnace.

According to the wear-resistant blade and its preparation method, the net voltage during the brush plating process is 14V; the voltage of the brush plating base layer is 16V; and the brush plating Ni-P/Al ₂ O ₃ adjustment layer preparation process conditions For positive connection, the voltage is 8V and the time is 2.5 hours.

Example 3

The atomic percentage of Al in the first layer of high-entropy alloy coating from the blade substrate to the surface is 6%; the atomic percentage of CoCrFeNi is 94%.

The thickness of each layer of Al _x CoCrFeNi high-entropy alloy coating is approximately 200 μm.

_The multi-layer structure of _the Al

The percentage of Al atoms between the four layers of Al _x CoCrFeNi high-entropy alloy coatings increases sequentially with a gradient of 5%;

There are three adjustment layers for regulating surface roughness and bonding strength between the four layers of Al _x CoCrFeNi high-entropy alloy coatings;

The adjustment layer is brush-plated Ni-P/Al ₂ O ₃ coating;

The components of the Ni-P/Al ₂ O ₃ adjustment layer include: brush plating solution and nano-alumina; the components of the brush plating solution are NiSO ₄ .7H ₂ O 40g/L, Na ₂ SO ₄ 4g/L , NaH ₂ PO ₂ .H ₂ O 8g/L, CH ₃ COOH 2.8g/L, C ₆ H ₈ O ₇ 5.0g/L, sodium dodecylbenzene sulfonate 0.10g/L, thiourea 0.04g/ L; the particle size of the nano-alumina is 20-30nm, and the concentration is 40g/L;

For the wear-resistant blade, the total thickness of the Al _x CoCrFeNi high-entropy alloy coating and the adjustment layer is approximately 800 μm.

The wear-resistant blade preparation method includes the following steps:

(1) Pretreat the blade substrate;

(2) A layer of Al _x CoCrFeNi high-entropy alloy coating is thermally sprayed on the blade surface obtained in the previous step;

(3) Perform vacuum heat treatment on the high-entropy alloy coating obtained in the previous step;

(4) Prepare an adjustment layer on the surface of the high-entropy alloy coating obtained in the previous step;

(5) Repeat steps (2), step (3), step (4), step (2), step (3), step (4), step (2) and step (3);

(6) The outermost AlCoCrFeNi high-entropy alloy coating is ground and polished to meet the accuracy requirements, that is, a four-layer high-entropy alloy coating is obtained on the blade base surface.

In the wear-resistant blade and its preparation method, the pretreatment includes surface grinding, surface cleaning and roughening. The grinding treatment is carried out by sand grinding; the surface cleaning includes deoxidation, oil removal, rust removal, and cleaning with absolute ethanol in an ultrasonic cleaner; the roughening treatment is sand blasting; the sand blasting and roughening adopts emery; emery The particle size is 800μm; the sandblasting pressure is 0.3MPa; the sandblasting time is 40s; the sandblasting distance is 40mm.

In the wear-resistant blade and its preparation method, thermal spraying adopts supersonic flame spraying technology, using hydrogen as fuel, oxygen as combustion-supporting gas, and nitrogen as powder-feeding carrier gas; the hydrogen flow rate is 800slpm; the oxygen flow rate is 300slpm; The nitrogen flow rate is 40slpm; the spraying distance is 300mm; the spraying angle is 90°; the powder feeding rate is 50g/min.

In the wear-resistant blade and its preparation method, each layer of high-entropy alloy coating is subjected to a separate vacuum heat treatment after preparation. Includes the following steps:

(1) Pretreatment: Air tightness inspection and sample cleaning of vacuum heat treatment equipment;

(2) Vacuuming: Place the sample into the vacuum heat treatment equipment, seal and evacuate until the vacuum degree in the furnace is less than 2×10 ^-4 Pa;

(3) Heating stage: Turn on the circulating water in the furnace body to keep the furnace wall at room temperature; after the vacuum degree meets the requirements, use the step heating method to effectively prevent the coating from cracking and reducing the density caused by the coating heating rate being too fast. First, Set the preset temperature to 50℃, turn on the heating switch, and then increase the preset temperature in steps of 50℃ until the temperature in the furnace rises to 600℃;

(4) Heat preservation stage: The heat preservation stage lasts for 4 hours;

(5) Cooling stage: Close the vacuum heat treatment equipment to ensure that the circulating water in the furnace is always running. cool down.

According to the wear-resistant blade and its preparation method, the net voltage during the brush plating process is 16V; the voltage of the brush plating base layer is 18V; and the brush plating Ni-P/Al ₂ O ₃ adjustment layer preparation process conditions For positive connection, the voltage is 10V and the time is 3 hours.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and illustration. These descriptions are not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical applications, thereby enabling others skilled in the art to make and utilize various exemplary embodiments of the invention and various different applications. Choice and change. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims (10)

1. A wear-resistant blade, characterized in that the blade includes a blade base 1, an Al _x CoCrFeNi high-entropy alloy coating 2 with a multi-layer structure located on the surface of the base, and the _Al Adjustment layer 3 is provided between _the entropy alloy coatings; the atomic percentage content of Al in each layer of the Al 2; The specific composition of the adjustment layer is Ni-P/Al ₂ O ₃ .
2. The wear-resistant blade according to claim 1, characterized in that:

   The Al _x CoCrFeNi high-entropy alloy coating with a multi-layer structure is at least two layers;

   From the blade substrate to the blade surface direction, the Al atomic percentage content between any two adjacent layers of the Al _x CoCrFeNi high-entropy alloy coatings increases sequentially with a gradient of not less than 5%.
3. The wear-resistant blade of claim 1, wherein the adjustment layer is a brush-plated Ni-P/Al ₂ O ₃ coating; the Ni-P/Al ₂ O ₃ coating includes nano-oxide Aluminum; the particle size of the nano-alumina is 20-30nm.
4. The wear-resistant blade of claim 1, wherein the total thickness of the Al _x CoCrFeNi high-entropy alloy coating with a multi-layer structure and the adjustment layer is 600 to 800 μm.
5. The preparation method of wear-resistant blades as claimed in claim 1, characterized in that it specifically includes the following steps:

   S1 pre-treats the blade substrate;

   S2 uses thermal spraying to prepare a layer of Al _x CoCrFeNi high-entropy alloy coating with high-entropy alloy powder;

   S3 performs vacuum heat treatment on the high-entropy alloy coating obtained in step S2;

   S4 prepare a layer of Ni-P/Al ₂ O ₃ adjustment layer on the surface of the high-entropy alloy coating treated in step S3;

   S5 cycles sequentially on the surface of the conditioning layer obtained in step S4: thermally spraying the high-entropy alloy coating using the method of step S2, vacuum heat treating the high-entropy alloy coating using the method of step S3, and performing vacuum heat treatment on the high-entropy alloy coating using the method of step S4. The adjustment layer is prepared by the method; wherein, the number of cycles of step S2 and step S3 is m times, and the number of cycles of step S4 is m-1 times; 2≤m≤4;

   S6 grinds and polishes the outermost Al _x CoCrFeNi high-entropy alloy coating after vacuum heat treatment to obtain a wear-resistant blade with multiple layers of high-entropy alloy coating.
6. The preparation method of claim 1, wherein in step S1, the pretreatment includes grinding, surface cleaning and roughening.
7. The preparation method according to claim 1, characterized in that in step S2, the specific operating steps of the thermal spraying are: using supersonic flame spraying technology, using hydrogen as fuel, oxygen as combustion-supporting gas, and nitrogen as powder-feeding carrier gas ;

   The hydrogen flow rate is 400～800slpm; the oxygen flow rate is 100～300slpm; the nitrogen flow rate is 20～40slpm; the spraying distance is 200～300mm;

   The spraying angle is 60°~90°; the powder feeding rate is 10~50g/min.
8. The preparation method according to claim 1, characterized in that, in step S3, the specific operating steps of the vacuum heat treatment are:

   S31 pre-treatment: air tightness inspection and sample cleaning of vacuum heat treatment equipment;

   S32 Vacuuming: Place the sample into the vacuum heat treatment equipment, seal and evacuate;

   S33 heating stage: turn on the circulating water in the furnace body to keep the furnace wall at room temperature; when the vacuum degree is less than 2×10 ^-4 Pa, adjust the preset temperature to 50°C, turn on the heating switch, and then increase it sequentially in units of 50°C Preset temperature until the temperature in the furnace rises to 400~600℃;

   S34 heat preservation stage: the heat preservation stage lasts 2 to 4 hours;

   S35 cooling stage: Turn off the vacuum heat treatment equipment and wait until the sample cools to room temperature before proceeding with subsequent operations.
9. The preparation method according to claim 1, characterized in that, in step S4, the specific operation steps of preparing the adjustment layer are: Ni-P/Al ₂ O ₃ coating prepared by brush plating, during the brush plating process The voltage of the electric net is 12~16V; the voltage of the brush plating base layer is 14~18V; the preparation process conditions of the brush plating Ni-P/Al ₂ O ₃ adjustment layer are positive connection, voltage 6~10V, time 2~4 hours.
10. An application of the wear-resistant blade according to any one of claims 1-4 or the wear-resistant blade prepared by the method according to any one of claims 5-9, characterized in that, as a turbine drilling tool blade.