A friction coating high-temperature resistant high-entropy alloy coating preparation device and method

Abstract

The present invention discloses a friction-coated, high-temperature-resistant high-entropy alloy coating preparation device and method, belonging to the technical field of high-entropy alloy coating preparation. The device comprises a friction coating portion and a feeding portion. The friction coating portion comprises a discharge barrel, a coating head, a motor, a threaded feed rod, a material plasticizing device, and a cooling and protection device. The feeding portion comprises a feeding hopper and a feed pipe, which is connected to the discharge barrel via the feed pipe. The device adopts an integrated design and can prepare high-entropy alloy coatings after preparatory steps such as checking device connection, operating stability, and feeding. The device can prepare single high-entropy alloy coatings, composition-gradient high-entropy alloy coatings, and composite high-entropy alloy coatings.

Description

Technical Field

[0001] The present invention belongs to the technical field of high entropy alloy coating preparation, and in particular relates to a friction-coated high-temperature resistant high entropy alloy coating preparation device and method. Background Art

[0002] With the rapid development of modern industrial technology, various mechanical components are placing higher demands on the high-temperature, corrosion, and wear-resistant properties of protective coatings on their surfaces. New high-temperature-resistant high-entropy alloy coatings are gaining increasing attention. High-entropy alloys are composed of four or more principal elements. Their multi-principal-element structure imparts high entropy, delayed diffusion, lattice distortion, and cocktail effects. The high-entropy effect refers to the alloy's high configurational entropy, which improves its thermal and structural stability. The delayed diffusion effect slows the diffusion rate between atoms, which helps maintain the alloy's microstructure at high temperatures, thereby maintaining its hardness and strength. The lattice distortion effect refers to the lattice distortion caused by multiple principal elements. This distortion can hinder dislocation motion and enhance the material's strength and hardness. The cocktail effect refers to the synergistic effect between multiple principal elements, resulting in a combination of properties, such as oxidation resistance, corrosion resistance, and wear resistance. Therefore, the excellent high-temperature properties of high-entropy alloys make them ideal candidates for the preparation of high-temperature protective coatings.

[0003] Existing high-temperature resistant coating preparation processes usually require heating the coating alloy to a semi-molten or molten state, such as thermal spraying technology, laser cladding, and self-propagating high-temperature synthesis technology. However, there are large differences in the melting point, density, and atomic radius of the multiple principal elements in high-entropy alloys, which leads to defects such as composition segregation, cracks, and holes during the cooling and solidification process after coating preparation, thereby seriously affecting the high-temperature oxidation resistance, corrosion resistance, and wear resistance of the high-entropy alloy coating. In addition, traditional high-temperature coatings usually require post-processing processes such as heat treatment and mechanical polishing after preparation, resulting in problems such as long coating preparation process, high cost, and difficulty in ensuring coating quality. Summary of the Invention

[0004] The present invention aims to overcome the shortcomings of the prior art by providing a friction-coated high-temperature-resistant high-entropy alloy coating preparation device and method. This approach addresses existing defects in the high-temperature-resistant high-entropy alloy coating, such as component segregation, cracks, and holes, as well as long process flows, high costs, and difficulty ensuring coating quality.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A friction-coated high-temperature resistant high-entropy alloy coating preparation device comprises a discharge barrel, wherein a cavity is provided inside the discharge barrel along an axial direction, a coaxial threaded feed rod is provided in the cavity, and a feed thread is provided on the outer wall of the threaded feed rod;

[0007] The upper end of the discharge cylinder is provided with a motor, and the power output end of the motor is connected to the upper end of the threaded feed rod; the side wall of the discharge cylinder is provided with a feeding hopper, and the discharge port of the feeding hopper is connected to the cavity;

[0008] A material plasticizing device and a cooling protection device are provided on the outside of the discharging barrel, the feeding hopper is above the material plasticizing device, and the material plasticizing device is at the upper end of the cooling protection device; a heating resistance wire is provided inside the material plasticizing device, and a medium pipeline is provided in the cooling protection device around the discharging barrel;

[0009] The lower end of the threaded feeding rod is detachably connected to a coating head, and the upper end surface of the coating head is rotatably connected to the lower end of the discharge cylinder;

[0010] A plurality of hollow through holes are provided inside the coating head, the upper ends of the hollow through holes are connected to the cavity, and the lower ends of the hollow through holes are connected to the outside world; a central friction convex head is provided at the center position of the bottom of the coating head, and a plurality of spiral convex heads are provided around the central friction convex head at the bottom of the coating head, and the hollow through hole is provided between the central friction convex head and the spiral convex head, and the spiral convex head is in the shape of an arc, and the bending direction of the arc is opposite to the rotation direction of the coating head; a coaxial annular groove is provided at the bottom of the coating head, and the spiral convex head is in the inner circle of the annular groove.

[0011] A further improvement of the present invention is:

[0012] Preferably, the central friction protrusion is a hemispherical protrusion or a truncated cone-shaped protrusion;

[0013] The bottom end diameter D1 of the central friction protrusion is ≤ D (D is the diameter of the threaded feed rod), and the height is 0.6 times the target thickness of the coating.

[0014] Preferably, the hollow through holes are equally divided around the circumference of the central friction convex head, and the diameter D2 of the circumscribed circle of the lower end outlet of the hollow through holes is greater than 2 times the diameter D1 of the bottom end of the central friction convex head;

[0015] The spiral convex head is arranged in equal parts around the circumference of the central friction convex head, and the spiral convex head is composed of a long arc side, a short straight side, a short arc side and a short straight side connected end to end; the vertices of the short straight side on the near-center side of the spiral convex head are distributed on a circle with a diameter D3 coaxial with the central friction convex head, and D3 is greater than 3D1; the vertices of the short straight side on the far-center side of the spiral convex head are distributed on a circle with a diameter D4 coaxial with the central friction convex head, and D4 is greater than 6D1; the extension line of the short arc side is tangent to the outlet edge of the lower end of the hollow through hole;

[0016] The long arc side and the short arc side of the spiral convex head have an radian of 1.5D2, the short straight side is perpendicular to the long arc side and the short arc side, the length of the short straight side is 0.5D1, and the height of the spiral convex head is 0.6 times the target thickness of the coating layer.

[0017] Preferably, an upwardly protruding connecting boss is provided at the center of the coating head, and the connecting boss is detachably connected to the lower end of the threaded feeding rod;

[0018] An upwardly protruding annular boss is circumferentially provided on the edge of the upper end surface of the coating head, and the annular boss is connected to the bottom of the discharge barrel through a double bearing.

[0019] Preferably, the material plasticizing device includes a shell, the shell is arranged on the cooling protection device, the heating resistance wire is arranged between the shell and the threaded feeding rod, each heating motor group is arranged vertically, all the heating resistance wires are arranged at equal intervals around the circumference of the discharge barrel, and each heating resistance wire is provided with a terminal head at the end;

[0020] The heating resistors are divided into three sections, arranged vertically from top to bottom: heating resistor 1, heating resistor 2, and heating resistor 3. Temperature sensor 1 is located at the upper end of heating resistor 1. Temperature sensor 2 is located vertically between heating resistors 1 and 2. Temperature sensor 3 is located vertically between heating resistors 2 and 3. Temperature sensor 4 is located vertically at the lower end of heating resistor 3. The temperature signals collected by the temperature sensors are transmitted back to the central control unit, which uses a PID control algorithm to adjust the heat output of each heating resistor. This multi-stage feedback temperature control system allows for more precise control of the heating process, ensuring temperature uniformity across the entire heating area and preventing overheating and energy waste.

[0021] The heating resistance wire has a broken line structure, a wave structure or a serpentine structure.

[0022] Preferably, the calculation formula for the number of heating resistance wires to be set is: f=3πd⁄4, where f is the number of heating resistance wires to be set, and d is the outer diameter of the discharge barrel.

[0023] Preferably, the cavity in the discharge barrel is divided into an upper cavity and a lower cavity. The inner diameter of the upper cavity is a fixed value, and the inner diameter of the lower cavity gradually decreases from top to bottom. The calculation formula of the inner diameter of the lower cavity is:

[0024] d2= (1)

[0025] —The angle between the gradient slope and the axis is in the optimal range of 5-25°, and the calculation formula is: ;

[0026] —The friction coefficient between the plasticized material and the inner wall of the discharge barrel is affected by the plasticized material system, the material of the inner wall of the discharge barrel and the temperature;

[0027] d1—the fixed diameter of the upper cavity of the discharge barrel, in mm;

[0028] —Total height of the inner wall of the variable diameter discharge barrel, in mm.

[0029] Preferably, the threaded feeding rod is arranged in the upper part of the cavity, and the outer wall is provided with a feeding thread.

[0030] Preferably, the hollow through holes are equally divided around the center of the coating head, and the transverse radius of the hollow through holes gradually decreases.

[0031] A method for preparing a high-temperature resistant high-entropy alloy coating by friction coating based on the above device comprises the following steps:

[0032] Step 1, connect the coating head and the discharge barrel;

[0033] Step 2: Move the coating head to the initial position of the workpiece and set the rotation speed, forward speed and forward route of the threaded feed rod;

[0034] Step 3: Add the coating raw material to the feeding hopper, and start the motor, material plasticizing device, and cooling protection device in sequence; the coating raw material moves downward in the cavity of the discharge barrel under the action of the threaded feed rod, and is discharged from the hollow through-hole of the coating head, and is evenly stirred by the central friction convex head and the spiral convex head. While stirring, the coating raw material is coated on the surface of the workpiece;

[0035] Step 4: After the coating head reaches the end position, the material plasticizing device (10), the cooling protection device and the motor are turned off in sequence.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention discloses a friction-coated, high-temperature-resistant high-entropy alloy coating preparation device. The device comprises a friction coating portion and a feeding portion. The friction coating portion comprises a discharge barrel, a coating head, a motor, a threaded feed rod, a material plasticizing device, and a cooling and protection device. The feeding portion comprises a feeding hopper and a feed pipe, which are connected to the discharge barrel via the feed pipe. The device utilizes an integrated design and can prepare high-entropy alloy coatings after undergoing preparatory steps such as device connection inspection, operational stability inspection, and material feeding. The device can prepare single high-entropy alloy coatings, composition-gradient high-entropy alloy coatings, and composite high-entropy alloy coatings. The device feeds raw materials into the discharge barrel via the feeding device, and a threaded feed rod inside the discharge barrel transports the raw materials downward and provides downward extrusion pressure. The downwardly transported raw materials sequentially pass through the material plasticizing device to complete the plasticization of the material body. The material plasticizing device precisely controls the material plasticization state through a multi-stage feedback control temperature system. The cooling protection device allows the passage of various cooling media, such as liquid and gas, to prevent the plasticizing unit from heating and damaging the lower coating head. The discharge barrel is divided into a fixed inner diameter section and a gradient inner diameter section. The fixed inner diameter section facilitates downward feed of the material by the feed screw, while the gradient inner diameter section evenly distributes the pressure of the plasticized material during downward extrusion and controls the flow rate and direction of the plasticized material. Furthermore, the uniform pressure distribution and low material flow rate within the gradient inner diameter hole help reduce wear on the inner wall of the discharge barrel, extending its service life. A stable volume of plasticized material enters the lower coating head through the gradient inner diameter discharge barrel and is extruded through the hollow through-hole of the coating head under the downward pressure of the feed screw. The extruded plasticized material is then coated by friction with the coating head. This friction coating section allows the high-entropy alloy coating to be applied in a semi-solid phase. The process temperature, below the melting point, eliminates the problem of composition segregation, cracks, and pores in the high-entropy alloy coating. The friction coating section features a spiral protrusion on the end face of the coating head. This spiral protrusion rotates and rubs against the coating, causing it to undergo intense plastic deformation. This further refines, densifies, and homogenizes the coating structure, achieving excellent surface quality. The coating prepared using this method exhibits a smooth surface, dense structure, uniform composition, and excellent performance. Furthermore, the device comprises an automated system consisting of a feeding section and a friction coating section, enabling integrated fabrication from feeding to coating preparation. This device has a simple structure and a high degree of automation, reducing labor and material costs during material preparation, particularly avoiding the high pollution and time-consuming nature of traditional preparation techniques.

[0038] The present invention also discloses a method for preparing a friction-coated high-temperature resistant high-entropy alloy coating, which first feeds the material through a feeding device, controls the parameters of a heating device and a cooling protection device, obtains a semi-solid coating pre-deposition body by heating through a plasticizing device and a cooling protection device of the material preparation main body, and friction-coates the pre-deposition body in the feeding cylinder, thereby realizing coating preparation. In the present invention, the high-entropy alloy coating refines, densifies, and homogenizes the surface coating structure through friction coating, which can improve the high-temperature oxidation resistance, corrosion resistance, and wear resistance of the coating. The device is simple to operate and has a short process flow. By adjusting the type, speed, and sequence of feeding powder, the preparation of a single alloy coating, a composition gradient coating, and a composite coating can be realized. The coating prepared by this method has a smooth surface, a dense structure, a uniform composition, and excellent performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic structural diagram of a friction-coated high-temperature-resistant high-entropy alloy coating preparation device according to the present invention;

[0040] Figure 2 This is a cross-sectional view of the inner wall of the fixed diameter discharge barrel of the present invention;

[0041] Figure 3 This is a cross-sectional view of the inner wall of the variable diameter discharge barrel of the present invention;

[0042] Figure 4 Schematic diagram of the material delivery conduit of the present invention;

[0043] Figure 5 This is a schematic diagram of the threaded feed rod of the present invention;

[0044] Figure 6 It is a schematic diagram of the wedge thread of the present invention;

[0045] Figure 7 This is a schematic diagram of the multi-stage feedback temperature control structure of the plasticizing device of the present invention.

[0046] Figure 8 1 is a schematic diagram of a coating head of the present invention;

[0047] Figure 9 2 is a schematic diagram of the coating head of the present invention;

[0048] Figure 10 It is a schematic diagram of a spiral convex head of the present invention.

[0049] Among them, 1-feeding hopper; 1-1 feeding splash guard; 2-first valve; 3-L-type feeding pipe; 3-1-L-type feeding pipe short pipe; 3-2-L-type feeding pipe long pipe; 4-feeding port; 5-motor; 6-fixed casing; 7-discharging barrel; 7-1-discharging barrel outer wall; 7-2-fixed diameter discharging barrel inner wall; 7-3 variable diameter discharging barrel inner wall; 7-4-upper part of the cavity; 7-5-lower part of the cavity; 8-threaded feeding rod; 9-feeding thread; 9-1-wedge-shaped thread flat top; 9-2-wedge-shaped thread bevel; 10-material plasticizing device; 10-1-connecting head; 10-2-heating resistance wire; 10-21-heating resistance wire one; 10-22-heating resistance wire two; 10-23-heating resistance wire three; 10-3-outer Shell; 10-4-temperature sensor; 10-41-temperature sensor one; 10-42-temperature sensor two; 10-43-temperature sensor three; 10-44-temperature sensor four; 10-5-main control terminal; 11-cooling protection device; 11-1-medium pipeline; 11-2-medium transmission pipeline; 12-second valve; 13-coating head; 13-1-connecting boss; 13-2-annular boss; 13-3-annular groove; 13-4-spiral boss; 13-41-long arc edge; 13-42-short arc edge; 13-43-short straight edge; 13-5-hemispherical boss; 13-6-circular discharge hole; 13-7-truncated cone boss; 13-8-elliptical discharge port; 13-9-hollow through hole. DETAILED DESCRIPTION

[0050] The present invention is described in further detail below with reference to the accompanying drawings:

[0051] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "horizontal", "inner", "outer" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention; the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; in addition, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be a communication between the internal parts of two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0052] See also Figure 1The present invention discloses a friction-coated high-temperature-resistant high-entropy alloy coating preparation device, which includes a feeding part and a coating part, and the feeding part is arranged on the coating part. The feeding part includes a feeding hopper 1 and an L-shaped feeding pipe 3. The main structure of the feeding hopper 1 is in an inverted cone shape. The upper edge of the feeding hopper 1 is provided with a feeding splash-proof edge 1-1. The lower end of the feeding hopper is connected to the L-shaped feeding pipe 3, and the L-shaped feeding pipe 3 is provided with a first valve 2. The coating part includes a discharge barrel 7, a threaded feeding rod 8, a material plasticizing device 10, a cooling protection device 11 and a coating head 13. The upper end of the discharge barrel 7 is connected to the fixed housing 6, and the outer side of the discharge barrel 7 at the lower part of the fixed housing 6 is provided with a feed port 4, and the feed port 4 is connected to the lower end of the L-shaped feeding pipe 3; the outer side of the discharge barrel 7 is sequentially provided with a material plasticizing device 10 and a cooling protection device 11; the feed port 4 is above the material plasticizing device 10, and the material plasticizing device 10 is at the upper end of the cooling protection device 11. A threaded feeding rod 8 is coaxially arranged inside the discharge barrel 7 , the upper end of the threaded feeding rod 8 is connected to a coaxial motor 5 , the motor 5 is arranged in a fixed housing 6 , and the lower end of the threaded feeding rod 8 is threadedly connected to a coating head 13 .

[0053] As a preferred solution, the feed port 4 is connected to the L-shaped feed pipe 3 in a split manner. The L-shaped feed pipe 3 is an integrated complex-shaped pipe, including an L-shaped feed pipe short pipe 3-1 and an L-shaped feed pipe long pipe 3-2. The L-shaped feed pipe short pipe 3-1 is vertically arranged, and the angle between the L-shaped feed pipe short pipe 3-1 and the L-shaped feed pipe long pipe 3-2 is 100-150°. The end of the L-shaped feed pipe short pipe 3-1 is connected to the first valve 2, and the end of the L-shaped feed pipe long pipe 3-2 is connected to the feed port 4.

[0054] As a preferred embodiment, the discharge barrel 7 is a variable inner diameter barrel. A cavity is provided along the length of the discharge barrel 7-1 for accommodating the threaded feed rod 8 and feed thread 9. The diameter of the outer wall 7-1 of the discharge barrel is fixed, and the cavity is divided into an upper cavity 7-4 and a lower cavity 7-5. The upper cavity 7-4 extends from the upper end of the discharge barrel 7 to the horizontal level of the bottom end of the material plasticizing device 10, and has a fixed inner diameter of d1. The cavity from the horizontal level of the material plasticizing device 10 to the bottom of the discharge barrel 7 is the lower cavity 7-5, and the inner diameter of the lower cavity 7-5 gradually decreases from top to bottom, with a variable diameter of d2. The gradient variable inner diameter section can evenly distribute the pressure of the plasticized material during downward extrusion and control the flow rate and direction of the plasticized material. In addition, the uniformly distributed pressure and low material flow rate within the gradient variable inner diameter hole help reduce wear on the inner wall of the discharge barrel, extending its service life. Therefore, the angle θ between the inclined surface of the inner wall of the lower cavity 7-5 and the axis should satisfy the following relationship. The gradient change of the inner diameter can ensure the smooth flow of the material and avoid excessive pressure and wear of the discharge barrel.

[0055]

[0056]

[0057] Simplified to get

[0058]

[0059] m—mass of plasticized material, unit: g;

[0060] —The friction coefficient between the plasticized material and the inner wall of the discharge barrel is affected by the plasticized material system, the material of the inner wall of the discharge barrel and the temperature;

[0061] —The angle between the gradient slope and the axis is recommended to be in the optimal range of 5-25°;

[0062] The calculation formula for the variable diameter d2 of the discharge barrel is:

[0063] d2= (1)

[0064] d1—fixed diameter of the upper cavity 7-4 of the discharge barrel, unit: mm;

[0065] —Total height of the inner wall 7-3 of the variable diameter discharge barrel, in mm.

[0066] The fixed diameter discharge barrel inner wall 7-2 facilitates the material transmission by the feeding screw, and the variable diameter discharge barrel inner wall 7-3 can slow down the material flow rate, which is beneficial to improving the flow state of the material and filling the pores to obtain a dense and uniform plasticized material body; the evenly distributed plasticized material pressure and low plasticized material flow rate help reduce the wear of the inner wall of the discharge barrel and extend its service life.

[0067] See also Figure 1 and Figure 2 The material plasticizing device 10 includes a shell 10-3, which is arranged on the cooling protection device 11. The shell 10-3 is composed of an outer arc surface, an upper annular surface and a lower annular surface, and is sealed at the top and bottom and on the outside. The shell body material is composed of ceramic fiber, refractory bricks, vermiculite, mineral wool multi-layer insulation layer and a stainless steel shell, which has good thermal insulation performance to ensure rapid heating and avoid energy dissipation; the heating resistance wire 10-2 is arranged between the shell 10-3 and the discharge barrel 7, and a plurality of heating resistance wires 10-2 are arranged around the discharge barrel 7. The length direction of the heating resistance wire 10-2 is parallel to the axial direction of the discharge barrel 7, and is arranged at equal intervals along the outer wall of the discharge barrel 7. The upper end of each heating resistance wire 10 is provided with a terminal 10-1, which is used to connect to an external power supply.

[0068] The heating resistors are divided into three sections, vertically arranged from top to bottom: heating resistor 10-21, heating resistor 2 10-22, and heating resistor 3 10-23. A temperature sensor 10-41 is located at the upper end of heating resistor 10-21. A temperature sensor 10-42 is located vertically between heating resistor 10-21 and heating resistor 2 10-22. A temperature sensor 10-43 is located vertically between heating resistor 2 10-22 and heating resistor 3 10-23. A temperature sensor 4 10-44 is located vertically at the lower end of heating resistor 3 10-23. The temperature signal collected by temperature sensor 10-4 is transmitted back to the main control terminal 10-5, which uses a PID control algorithm to adjust the heat output of each heating resistor 10-2. This multi-stage feedback temperature control system allows for more precise control of the heating process, ensuring temperature uniformity across the entire heating area and preventing overheating and energy waste.

[0069] As a preferred solution, each heating resistance wire 2 has a broken line structure, a wavy structure or a serpentine structure, which extends the stroke length of the heating resistance wire 2 in the space, so that the heating resistance wire 2 can not only fully heat the side wall of the discharge barrel 7, but also fully heat the air in the space, reducing the heat dissipation of the heating resistance wire 2.

[0070] As a preferred solution, the number f of the heating resistance wires 10-2 can be changed according to the diameter d of the discharge barrel 7, and the relationship is: f=3πd⁄4, the temperature of the material plasticizing device 10 can be set, and the heating temperature T r The calculation formula is:

[0071] (2)

[0072] k-empirical coefficient, take 0.5-0.7;

[0073] a-principal element number of high entropy alloy;

[0074] c i — represents the atomic percentage of the 𝑖th component in the alloy system;

[0075] (T m ) i — represents the melting point of the 𝑖th element in the alloy system.

[0076] See also Figure 1 and Figure 3 The cooling protection device 11 includes a medium transmission pipeline 11-2, a medium pipeline 11-1 and a second valve 12. The medium pipeline 11-1 is threadedly wrapped around the outer wall of the discharge barrel 7 and connected to the medium transmission pipeline 11-2. The second valve 12 is set on the medium transmission pipeline 11-2.

[0077] The cooling protection device 11 includes a medium pipeline 11-1 wrapped around the outer wall of the discharge barrel 7. The vertical cross-section of the medium pipeline 11-1 is semicircular with a cross-sectional radius of r. A medium transmission pipeline 11-2 is integrally connected to each end of the medium pipeline 11-1. The two medium transmission pipelines 11-2 are respectively arranged on the upper and lower end surfaces of the cooling protection device 11. The two medium transmission pipelines 11-2 are arranged horizontally, with their axes oriented horizontally. The angle between the two medium transmission pipelines 11-2 is 180°, that is, they are arranged on either side of the discharge barrel 7. Each end of the medium transmission pipeline 11-2 is connected to an external medium input port and a medium output port. A second valve 12 is provided at the outer end of each medium transmission pipeline 11-2. The cooling protection device 11 can be fed with different constant temperature media such as liquid and gas, and the cooling rate can be controlled by changing the medium type and flow rate. The purpose of the cooling protection device 11 is to prevent heat generated by the plasticizing device from damaging the lower coating head. In addition, the medium should be selected to ensure that the plasticized state of the material allows for uniform coating.

[0078] As a preferred solution, the end of each medium transmission pipeline 11 - 2 protrudes from the plane of its end surface to facilitate communication with an external medium pipeline.

[0079] It should be noted that, one of the two medium transmission pipelines 11 - 2 is an input pipeline and the other is an output pipeline, and the specific one can be adjusted according to the actual needs of the application.

[0080] Unlike traditional alloy materials, high-entropy alloys have multiple main elements, and the atomic diameters, diffusion capabilities, interactions between elements and melting points of each element vary greatly, which easily leads to segregation and defects. A multi-stage plasticizing device 10 with a feedback control temperature system is required to ensure the uniformity of the plasticized material. A uniform and dense plasticized material body is obtained through the combined action of the plasticized material's own gravity and the extrusion of the feeding screw 9 in the inner wall of the variable-diameter discharge barrel 7-3 stage.

[0081] See also Figure 1 and Figure 5 The threaded feed rod 8 is located inside the discharge barrel 7 and extends along its length. It is coaxial with the discharge barrel 7. Its upper end is connected to the power output of the motor 5, and its lower end is connected to the coating head 13. Feed threads 9 are located outside the feed rod 8. Their upper end is one pitch h higher than the feed port 4, and their lower end is flush with the bottom of the material plasticizing device 10. The threaded feed rod 8 has a rotational speed of 0-2000 rpm and an axial top pressure of 0-100 kN.

[0082] As a preferred solution, see Figure 5 and Figure 6The threaded feed rod 8 has a diameter of D (1.5D = d1). The feed thread 9 has a wedge-shaped thread with a trapezoidal cross-section, including an outer wedge-shaped flat top 9-1. The two sides of the wedge-shaped flat top 9-1 are integrally connected to the ends of the wedge-shaped bevel 9-2. The other end of the wedge-shaped bevel 9-2 is integrally connected to the outer side of the threaded feed rod 8. The wedge surface has a slope γ of 30°, the thread rotates clockwise, the thread pitch h is 0.5-1.5D, and the feed thread 9 has a diameter of 2D.

[0083] See also Figure 1 and Figure 8 The bottom of the threaded feed rod 8 is connected to the coating head 13. The coating head 13 is provided with a vertical hollow through-hole 13-9 around its central axis. The hollow through-hole 13-9 passes through the upper and lower end surfaces of the coating head 13 and is used for extruding the plasticized material. During the extrusion, a dense and smooth coating is applied through the rotational friction of the bottom of the coating head 13. The central part of the coating head 13 is provided with an upwardly protruding connecting boss 13-1. The connecting boss 13-1 is coaxial with the threaded feed rod 8. The connection method between the connecting boss 13-1 and the threaded feed rod 8 includes but is not limited to a threaded connection 13-1, a key connection and a pin connection. As a preferred solution, the side wall of the connecting boss 13-1 is provided with a threaded structure, which can be inserted into the threaded feed rod 3 from the bottom for easy disassembly, so that the coating head 13 can be threadedly connected to the bottom of the threaded feed rod 8 to achieve power transmission. An upwardly protruding annular boss 13-2 is provided around the circumference of the upper end surface of the coating head 13. The annular boss 13-2 is connected to the bottom of the discharge barrel 7 through a double bearing, thereby ensuring the airtightness of the lower end of the discharge barrel and preventing the plasticized material from overflowing.

[0084] As a preferred solution, the longitudinal cross-section of each hollow through hole 13-9 is trapezoidal, and the transverse radius of the hollow through hole 13-9 gradually decreases from top to bottom to facilitate the extrusion of the plasticized material.

[0085] As a preferred solution, the hole shape of each hollow through hole 13-9 includes but is not limited to a circular discharge hole 13-6 and an elliptical discharge hole 13-8. The size and number of the discharge holes can be customized according to the discharge volume required by actual working conditions.

[0086] In some embodiments of the present invention, an annular groove 13-3 with the same center is provided on the lower end surface of the coating head 13. The inner diameter of the annular groove 13-3 is 3 / 5d3 (d3 is the coating head diameter, unit: mm), the outer diameter range is 7 / 10-9 / 10d3, and the groove depth is 2 mm. The inner diameter of the annular groove 13-3 should be larger than the circumscribed diameter of the spiral protrusion 13-4, and the outer diameter range should be smaller than the coating head 13 diameter. The depth and width are selected with the goal of changing the material flow state and forming an excellent coating surface quality. The function of the annular groove 13-3 is to transform the flow state of the plasticized material extruded along the circumferential direction of the coating head 13 into a downward flow. The change in the material flow state can eliminate defects in the coating thickness direction and increase the bonding strength between the coating and the coated workpiece.

[0087] A central friction protrusion is provided at the center of the lower end surface of coating head 13. Its shapes include, but are not limited to, a hemispherical protrusion 13-5 and a truncated cone-shaped protrusion 13-7. The diameter of the end surface of hemispherical protrusion 13-5 where it contacts coating head 13 is D1, and its height is 0.6 times the required coating thickness. The diameter of truncated cone-shaped protrusion 13-7 where it contacts coating head 13 is D1, and its outermost end surface has a diameter of 0.6D1 and a height of 0.6 times the required coating thickness. The central friction protrusion densifies and evens out the coating at the center of coating head 13, preventing accumulation of material extruded from the discharge port in the center of the coating.

[0088] See also Figure 10 The spiral convex head 13-4 is equally divided around the circumference of the central friction convex head 13-5, and the spiral convex head is composed of a long arc side 13-41, a short arc side 13-42 and two short straight sides 13-43; the vertices of the short straight sides 13-43 on the near-center side of the spiral convex head 13-4 are distributed on the circumference of the circle with the same center diameter D3 as the central friction convex head 13-5, and D3 should be greater than 3D1; the vertices of the short straight sides 13-43 on the far-center side of the spiral convex head 13-4 are distributed on the circumference of the circle with the same center diameter D3 as the central friction convex head 13-5, and D3 should be greater than 3D1; The head 13-5 is concentrically located on a circle with a diameter D4, where D4 should be greater than 6D1. The extended line of the short arc edge 13-42 is inscribed within the lower outlet edge of the hollow through-hole 13-9. The long arc segments 13-41 and the short arc segments 13-42 of the spiral convex head each have an arc angle of 1.5D2. The short straight edge 13-43 is perpendicular to the long arc segments 13-41 and the short arc segments 13-42, and the length of the short straight edge 13-43 is 0.5D1. The height of the spiral convex head 13-4 is 0.6 times the target coating thickness. The arc of the spiral convex head 13-4 is curved in the opposite direction to the rotation direction of the coating head 13. This opposite arc direction facilitates the rapid flow of the material in the circumferential direction, preventing clogging of the discharge port 13-6, and promotes the densification and uniformity of the coating material. The spiral convex head changes the material flow direction and accelerates the flow of extruded material at the discharge port, thereby preventing clogging.

[0089] The raw materials added to the friction coating high-temperature resistant high-entropy alloy coating preparation device include but are not limited to high-entropy alloy powder, particles, and debris.

[0090] Through the above device, the coating preparation method of the friction coating high temperature resistant high entropy alloy coating preparation device includes the following steps:

[0091] Step 1: Install the coating head 13, then start the motor 5, material plasticizing device 10 and cooling protection device 11 in sequence, and check whether the device is running stably. After checking that the operation is normal, turn off the material plasticizing device 10, cooling protection device 11 and motor 5 in sequence;

[0092] Step 2: Install the workpiece to be coated, program the processing equipment system, set the rotation speed, forward speed, and forward route of the threaded feed rod 8, and further control the processing process by manually controlling the moving handle to move the coating head 13 to the initial processing position, obtain the rough coordinates of the processing start position, and input the precise processing start position into the program through the judgment of the engineer. The end point is determined according to the requirements, and the lower end of the coating head 13 is adjusted to the predetermined position on the surface of the workpiece to be coated, and the height from the plate surface is the predetermined coating thickness;

[0093] Step 3, add the coating raw material to the feeding hopper 1; start the motor 5, the material plasticizing device 10, the cooling protection device 11 and the first valve 2 in sequence, and when the plasticized coating raw material is stably extruded from the lower end of the coating head 13, the coating is applied according to the predetermined speed, forward speed and path; in this process, the motor 5 is started to drive the threaded feeding rod 8 to rotate, and the coating raw material gradually moves downward under the action of the feeding thread on the threaded feeding rod 8. When it moves to the material plasticizing device 10, the coating raw material is evenly heated and has better fluidity. After the coating raw material flows out through the coating head 13, it reaches the surface of the workpiece and is evenly stirred by the central friction convex head and the spiral convex head 13-4 on the surface of the workpiece.

[0094] Step 4: When the coating head 13 reaches the end position, the first valve 2, the material plasticizing device 10, the cooling protection device 11 and the motor 5 are closed in sequence;

[0095] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A friction coating high temperature resistant high entropy alloy coating preparation device, characterized in that, The material discharging cylinder (7) comprises a cavity provided inside the material discharging cylinder (7) along the axial direction, a coaxial threaded feeding rod (8) is provided in the cavity, and a feeding thread (9) is provided on the outer wall of the threaded feeding rod (8); The upper end of the discharge barrel (7) is provided with a motor (5), and the power output end of the motor (5) is connected to the upper end of the threaded feed rod (8); the side wall of the discharge barrel (7) is provided with a feeding hopper (1), and the discharge port of the feeding hopper (1) is connected to the cavity; A material plasticizing device (10) and a cooling protection device (11) are provided on the outside of the discharge barrel (7); the feeding hopper (1) is above the material plasticizing device (10), and the material plasticizing device (10) is at the upper end of the cooling protection device (11); a heating resistance wire (10-2) is provided inside the material plasticizing device (10), and a medium pipeline (11-1) is provided in the cooling protection device (11) around the discharge barrel (7); The lower end of the threaded feeding rod (8) is detachably connected to a coating head (13), and the upper end surface of the coating head (13) is rotatably connected to the lower end of the discharge barrel (7); The coating head (13) is provided with a plurality of hollow through holes (13-9) inside, the upper end of the hollow through hole (13-9) is connected to the cavity, and the lower end of the hollow through hole (13-9) is connected to the outside world; a central friction convex head is provided at the center position of the bottom of the coating head (13), and a plurality of spiral convex heads (13-4) are provided around the central friction convex head at the bottom of the coating head (13), the hollow through hole (13-9) is provided between the central friction convex head and the spiral convex head (13-4), the spiral convex head (13-4) is in the shape of an arc, and the curvature direction of the arc is opposite to the rotation direction of the coating head (13); a coaxial annular groove (13-3) is provided at the bottom of the coating head (13), and the spiral convex head (13-4) is in the inner circle of the annular groove (13-3).

2. The friction coating high temperature resistant high entropy alloy coating preparation device according to claim 1 is characterized in that: The central friction convex head is a hemispherical convex head (13-5) or a truncated cone convex head (13); The bottom end diameter D1 of the central friction protrusion is ≤ D (D is the diameter of the threaded feed rod), and the height is 0.6 times the target thickness of the coating.

3. The friction coating high temperature resistant high entropy alloy coating preparation device according to claim 1, characterized in that: The hollow through holes (13-9) are equally divided around the circumference of the central friction convex head (13-5), and the diameter D2 of the circumscribed circle of the lower end outlet of the hollow through holes (13-9) is greater than twice the diameter D1 of the bottom end of the central friction convex head (13-5); The spiral convex head (13-4) is equally divided around the circumference of the central friction convex head (13-5), and the spiral convex head (13-4) is composed of a long arc side (13-41), a short straight side (13-43), a short arc side (13-42), and a short straight side (13-43) connected end to end; the vertices of the short straight side (13-43) on the near-center side of the spiral convex head (13-4) are distributed on a circumference with a diameter D3 co-centered with the central friction convex head (13-5), and D3 is greater than 3D1; the vertices of the short straight side (13-43) on the far-center side of the spiral convex head (13-4) are distributed on a circumference with a diameter D4 co-centered with the central friction convex head (13-5), and D4 is greater than 6D1; the extension line of the short arc side (13-42) is tangent to the outlet edge of the lower end of the hollow through hole (13-9); The long arc side (13-41) and the short arc side (13-42) of the spiral convex head have an arc angle of 1.5D2, the short straight side (13-43) is perpendicular to the long arc side (13-41) and the short arc side (13-42), the length of the short straight side (13-43) is 0.5D1, and the height of the spiral convex head (13-4) is 0.6 times the target thickness of the coating layer.

4. The friction coating high temperature resistant high entropy alloy coating preparation device according to claim 1, characterized in that: An upwardly protruding connection boss (13) is provided at the center of the coating head (13), and the connection boss (13) and the lower end of the threaded feed rod (8) are detachably connected; An upwardly protruding annular boss (13-2) is provided around the circumference of the upper end surface edge of the coating head (13), and the annular boss (13-2) is connected to the bottom of the discharge barrel (7) via a double bearing.

5. The friction coating high temperature resistant high entropy alloy coating preparation device according to claim 1, characterized in that: The material plasticizing device (10) includes a housing (10-3), the housing (10-3) is arranged on the cooling protection device (11), and a plurality of rows of heating resistance wires (10-2) are arranged between the housing (10-3) and the threaded feeding rod (8), each row of heating resistance wires (10-2) is arranged vertically, and all the heating resistance wires (10-2) are arranged at equal intervals around the circumference of the discharge barrel (7), and a terminal head (10-1) is provided at the end of each row of heating resistance wires (10); Each row of heating resistance wires (10) is divided into three parts, which are arranged vertically from top to bottom: heating resistance wire one (10-21), heating resistance wire two (10-22) and heating resistance wire three (10-23); a temperature sensor one (10-41) is provided at the vertical upper end of heating resistance wire one (10-21); a temperature sensor two (10-42) is provided vertically between heating resistance wire one (10-21) and heating resistance wire two (10-22); a temperature sensor three (10-43) is provided vertically between heating resistance wire two (10-22) and heating resistance wire three (10-23); and a temperature sensor four (10-44) is provided at the vertical lower end of heating resistance wire three (10-23); all temperature sensors are connected to a main control terminal (10-5); The heating resistance wire (2) has a broken line structure, a wave structure or a serpentine structure.

6. The friction coating high temperature resistant high entropy alloy coating preparation device according to claim 5, characterized in that: The calculation formula for the number of heating resistance wires (2) is: f=3πd⁄4, wherein f is the number of heating resistance wires (2) and d is the outer diameter of the discharge barrel (7).

7. The friction coating high temperature resistant high entropy alloy coating preparation device according to claim 1, characterized in that: The cavity in the discharge barrel (7) is divided into an upper cavity (7-4) and a lower cavity (7-5). The inner diameter of the upper cavity (7-5) is a fixed value, and the inner diameter of the lower cavity (7-5) gradually decreases from top to bottom. The calculation formula of the inner diameter of the lower cavity (7-5) is: d2= （1） —The angle between the gradient slope and the axis is in the optimal range of 5-25°, and the calculation formula is: ; —The friction coefficient between the plasticized material and the inner wall of the discharge barrel is affected by the plasticized material system, the material of the inner wall of the discharge barrel and the temperature; d1—the fixed diameter of the upper cavity (7-4) of the discharge barrel, in mm; —Total height of the inner wall (7-3) of the variable diameter discharge barrel, in mm.

8. The friction coating high temperature resistant high entropy alloy coating preparation device according to claim 7, characterized in that: The threaded material feeding rod (8) is arranged in the upper cavity (7-5), and a material feeding thread (9) is provided on the outer wall.

9. The friction coating high temperature resistant high entropy alloy coating preparation device according to claim 1, characterized in that: The hollow through holes (13-9) are equally divided around the center of the coating head (13), and the transverse radius of the hollow through holes (13-9) gradually decreases.

10. A method for preparing a high-temperature resistant high-entropy alloy coating by friction coating based on the device according to claim 1, characterized in that: The following steps are involved: Step 1, connecting the coating head (13) and the discharge barrel (7); Step 2, moving the coating head (13) to the initial position of the workpiece, and setting the rotation speed, forward speed and forward route of the threaded feed rod (8); Step 3, adding the coating raw material to the feeding hopper (1), and starting the motor (5), the material plasticizing device (10) and the cooling protection device (11) in sequence; the coating raw material moves downward in the cavity of the discharge barrel (7) under the action of the threaded feeding rod (8), is discharged from the hollow through hole (13-9) of the coating head (13), and is evenly stirred by the central friction convex head and the spiral convex head (13-4). While stirring, the coating raw material is coated on the surface of the workpiece; Step 4: After the coating head (13) reaches the end position, the material plasticizing device (10), the cooling protection device (11) and the motor (5) are turned off in sequence.

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