Method and device for preparing heterogeneous nanostructure by deformation-assisted jet electro-deposition

Abstract

The application provides a method for preparing heterogeneous nanostructures by deformation-assisted jet electro-deposition, comprising the following steps: (1) building a deformation-assisted jet electro-deposition environment; (2) connecting a power supply to spray the electroplating liquid from a spraying head, so that ion reduction occurs in the area impacted by the jet on the surface of a cathode plate, and a deposition layer is formed; (3) controlling the movement of a three-dimensional moving platform, so that a plastic deformation module contacts the cathode plate, and then the plastic deformation module applies a preset loading force to the deposition layer, so that plastic deformation occurs in the deposition layer; (4) repeatedly performing steps 2-3, the plastic deformation module follows the movement path of the spraying head, and layer-by-layer deposition and deformation of the heterogeneous nanostructures are performed until the preparation of the heterogeneous nanostructures is completed. By introducing strong plastic deformation assistance in the process of jet electro-deposition, the application can prepare bulk heterogeneous nanostructures, and the regulation of the structures of various components has greater freedom. The application also simultaneously provides a device for implementing the method.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of heterogeneous nano-material preparation, and particularly relates to a method and device for preparing heterogeneous nano-structure by deformation-assisted jet electrodeposition. BACKGROUND

[0002] Heterogeneous nano-structure is a general term for a new type of material developed with modern preparation technology and structure design. This type of material has multi-scale nano-domain structure, thereby showing excellent comprehensive mechanical properties that homogeneous materials cannot obtain, and is an effective solution to make up for the plasticity loss of nano-metal materials and realize comprehensive performance optimization. For example, gradient nano-structure can make nano-crystalline copper maintain high strength while having excellent plastic deformation capacity; introducing nano-domain structure into pure nickel makes the strength of pure nickel reach 24 times that of coarse-grained nickel, and the uniform elongation rate is as high as 30%. Under the trend of rapid development of nano-materials, new heterogeneous structures such as bimodal structure, multi-level twin structure, sandwich structure, dual / multi-phase structure, and reverse gradient nano-structure have been discovered and proposed. With the increasing application demand of heterogeneous nano-materials, how to realize the preparation of large-size heterogeneous nano-materials, the unification of various heterogeneous structures, and the superposition between various heterogeneous elements is a challenging problem.

[0003] At present, the preparation methods of heterogeneous nano-structure materials include plastic deformation plus (or not) heat treatment. This method has prepared most of the gradient structures and multi-element cross-scale structures. Its main limitation is that the regulation range of heterogeneous nano-structure components is limited, such as the gradient in gradient structure and the component distribution and morphology in multi-element structure. Another type is various physical or chemical deposition methods such as direct current electrodeposition, pulse electrodeposition, jet electrodeposition, and magnetron sputtering. This type of method can prepare nano-twin structure, lamellar structure, and gradient structure. However, this type of method more or less faces the phenomena of sharp discharge, grain preferential growth, and stress cracking, and it is difficult to control the structure. Therefore, except for a few cases, the samples prepared by this type of method are usually thin films.

[0004] In the process of electrodeposition of nano-metal, the bottom layer is equiaxed crystal. With the gradual increase of the deposition layer, part of the grains obtain a faster growth rate under the action of preferential growth, and occupy the growth space of other grains, forming columnar crystals. Columnar crystals usually have the same crystal face family (such as {111} crystal face family for deposited copper), and growth stress occurs between the grains, which promotes the initiation of cracks, thereby limiting the overall thickness of the deposition layer.

[0005] The Chinese invention patent with the patent publication number CN113445077A discloses a preparation method of a grain size multi-peak distribution heterogeneous nano-structure Cu. The process is to use layered nano-structure Cu as a template to first electrodeposit through a combination of electrodeposition and heat treatment, and then place it in a tube furnace for heating, holding and cooling to obtain the grain size multi-peak distribution heterogeneous nano-structure Cu. This method is suitable for preparing a strengthening coating on the surface of a metal material, but is limited by grain preferred growth and interlayer residual stress, and the sample size (in the thickness direction) is limited; in addition, this method cannot realize the regulation of the nanocrystalline microstructure in the same deposition layer, and the size, distribution and proportion of the grains cannot be effectively controlled in the same deposition layer.

[0006] The Chinese invention patent with the patent publication number CN112877750A discloses a device and a preparation method for a multi-functional field assisted jet flow electrodeposition nano-composite layer. In this method, a nano-composite deposition layer is prepared by using jet flow electrodeposition technology under the combined multi-functional field of electricity-magnetism-ultrasound. This method aims to solve the problems of nano-particle agglomeration, poor uniformity and consistency of the film layer, and the like, but the regulation of the size, distribution and proportion of the microstructure (including twin crystals, lamellas and grains) in the deposition layer is poor or not concerned. Moreover, the deposition layer is limited in the thickness direction due to the grain preferred growth and interlayer residual stress, and the application direction is limited to metal surface repair and strengthening, and cannot be used to prepare bulk heterogeneous nano-structure materials. SUMMARY

[0007] The present application provides a deformation assisted jet flow electrodeposition method for preparing heterogeneous nano-structure, which introduces strong plastic deformation assistance in the jet flow electrodeposition process to prepare bulk heterogeneous nano-structure, and the regulation of each component structure in the heterogeneous nano-structure has greater freedom. The present application also provides a device for implementing the method.

[0008] The present application is achieved by the following technical solutions:

[0009] A deformation assisted jet flow electrodeposition method for preparing heterogeneous nano-structure, comprising the following steps:

[0010] Step one: build a deformation assisted jet flow electrodeposition environment, specifically including:

[0011] The plastic deformation module, the spraying head and the cathode table are all installed on the three-dimensional moving platform, so that the cathode table can move up and down along the Z-axis direction, the plastic deformation module and the spraying head can move along the X-axis direction and the Y-axis direction, and the plastic deformation module and the spraying head are arranged above the cathode table; the cathode table is clamped and fixed with a cathode plate, and the cathode plate is connected with the cathode of the power supply; the spraying head comprises a spraying head shell and at least one nozzle pipe, the nozzle pipe is provided with an anode wire, and the anode wire is connected with the anode of the power supply; the electroplating liquid can be sent to the spraying head at a set flow rate through an electroplating liquid circulating unit;

[0012] Step two: turn on the power supply to spray the electroplating liquid from the spraying head, so that the heterogeneous nanostructure ion reduction occurs in the area of the jet impact on the surface of the cathode plate, and a deposition layer is formed;

[0013] Step three: control the three-dimensional moving platform to move, so that the cathode plate is in contact with the plastic deformation module, and then the plastic deformation module is used to apply a preset loading force to the deposition layer, so that the deposition layer is plastically deformed;

[0014] Step four: repeatedly perform steps two to three to perform layer-by-layer deposition of the heterogeneous nanostructure, and the plastic deformation module follows the movement path of the spraying head to plastically deform each deposition layer until the preparation of the heterogeneous nanostructure is completed.

[0015] The application also provides a device for preparing a heterogeneous nanostructure by deformation-assisted jet electrodeposition, which comprises a control module, a jet electrodeposition module and a plastic deformation module.

[0016] The control module comprises a three-dimensional moving platform and an industrial computer connected with the three-dimensional moving platform, the industrial computer is used to convert modeling graphic data into motion control data and output the motion control data to the three-dimensional moving platform, so as to control the three-dimensional motion of the three-dimensional moving platform in the X / Y / Z direction;

[0017] The jet electrodeposition module comprises a power supply, a spraying head, a cathode table and an electroplating liquid circulating unit; the electroplating liquid circulating unit is used to send the electroplating liquid to the spraying head at a set flow rate; the spraying head and the cathode table are both installed on the three-dimensional moving platform, the cathode table can move up and down along the Z-axis direction, the spraying head can move along the X-axis direction and the Y-axis direction, and the spraying head is arranged above the cathode table; the cathode table is clamped and fixed with a cathode plate, and the cathode plate is connected with the cathode of the power supply; the spraying head comprises a spraying head shell and at least one nozzle pipe, the nozzle pipe is provided with an anode wire, and the anode wire is connected with the anode of the power supply;

[0018] The plastic deformation module is used to apply an acting force to the deposition layer after jet deposition, so that the deposition layer is plastically deformed; the plastic deformation module is integrated with the spraying head or is independently arranged.

[0019] The present application has the following advantages:

[0020] (1) The existing deposition method prepares a heterogeneous nanostructure sample basically as a thin film, which is used as a reinforced plating layer. On the basis of the existing jet flow electrodeposition method, a synchronous or independent plastic deformation module (such as rolling, impact, torsion, etc.) is added. If the plastic deformation module is a roller, rolling deformation can be realized. If it is a micro punch, high-frequency impact on the local area can be realized. If it is a plane torsion head, the deposited layer can be twisted and rolled. The superposition of plastic deformation during jet flow deposition can cause the grains in the deposited layer to deform, refine and turn, thereby destroying the preferred growth of the grains, eliminating the columnar crystals and the source of the growth residual stress. At the same time, plastic deformation is also a commonly used residual stress release mechanism, and the grains release the growth residual stress through plastic deformation. Each movement of the spraying head will leave a very thin deposited layer on the moving path, and the plastic deformation module following the spraying head will deform this layer of deposited layer. When the spraying head moves repeatedly along the set path, a new deposited layer without deformation is generated, which is then processed by the plastic deformation module. Through such layer-by-layer plastic deformation, the residual stress in the deposited layer can be effectively released, thereby solving the problems of preferred growth of grains, cracking, etc.

[0021] (2) The existing deposition method can only adjust the parameters to form different deposited layers, and the structure of the same deposited layer cannot be controlled. The present application can realize the structure adjustment of the same deposited layer by adjusting the plastic deformation module. The present application can engrave the designed coarse crystal morphology, distribution and proportion on the roller. During deposition, the rolling roller rolls the deposited layer to form fine grains, while the deposited layer in the hollow part grows without deformation, forming coarse grains, thereby realizing the controllable and adjustable morphology, distribution and proportion of coarse grains, and obtaining a heterogeneous nanostructure with coarse grains embedded in a fine grain matrix. Similarly, during deposition, the impact module is selected to impact and deform at the preset position to obtain fine grains, while the remaining deposited layer grows without being affected, thereby obtaining a heterogeneous nanostructure with fine grains embedded in coarse grains.

[0022] (3) The existing deposition method can only control the grain size. By adjusting the loading force, strain rate and other parameters of the plastic deformation module, the present application can obtain a solid phase transition in the deposited metal, realize the mixing of multiple nanostructures, and expand the range of heterogeneous nanostructures. For example, pure nickel can form a nano-twin structure through twinning under high strain rate impact deformation, and stainless steel can undergo martensitic phase transition under impact or torsion.

[0023] (4) The existing deposition method can usually only use one kind of metal. By improving the spraying head, the present application can alternately spray different plating liquids to realize the alternate or co-deposition of different metals. Solid-phase microparticles such as nanodiamonds and aluminum oxide particles can also be mixed in the spraying liquid to co-deposit with pure metals and form a composite metal structure. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 Schematic diagram of a device for preparing heterogeneous nanostructure by deformation-assisted jet electrodeposition;

[0025] Figure 2 Schematic diagram of a plastic deformation module structure;

[0026] Figure 3 Partial sectional view of a plastic deformation module;

[0027] Figure 4 Structure diagram of a ceramic engraving roller;

[0028] Figure 5 Structure diagram of a plastic deformation module as a plane torsion head;

[0029] Figure 6 Structure diagram of a plastic deformation module as an impact punch;

[0030] Figure 7 Sample diagram of a single metal copper heterogeneous nanostructure; wherein a is a preparation sample; b is a laser three-dimensional topography scanning structure of a sample surface; c is a sample cross-sectional SEM observation microstructure diagram; DETAILED DESCRIPTION

[0031] The present application will be further described in detail below in conjunction with the drawings and specific embodiments.

[0032] As shown in the drawings, Figures 1-6 The present application provides a device for preparing heterogeneous nanostructure by deformation-assisted jet electrodeposition, which comprises a control module, a jet electrodeposition module and a plastic deformation module.

[0033] The control module comprises a three-dimensional moving platform 5, and an industrial computer 11 connected thereto, wherein the industrial computer 11 is used to convert modeling graphic data into motion control data and output to the three-dimensional moving platform 5 to control the three-dimensional motion of the three-dimensional moving platform 5 in X / Y / Z directions.

[0034] The jet electrodeposition module comprises a power supply, a spraying head 2, a cathode table 6 and an electroplating liquid circulating unit.

[0035] The spraying head 2 and the cathode table 6 are both installed on the three-dimensional moving platform 5, the cathode table 6 can move up and down along the Z-axis direction, the spraying head 2 can move along the X-axis direction and the Y-axis direction, and the spraying head 2 is arranged above the cathode table 6.

[0036] The cathode plate is fixed on the cathode table 6 and connected to the cathode of the power supply. The sputtering head 2 includes a sputtering head shell 20 and at least one nozzle pipe, in which an anode wire 1 is arranged, and the anode wire 1 is connected to the anode of the power supply. When two or more nozzle pipes are used, different metal species can be alternately grown or simultaneously grown.

[0037] The electroplating solution circulating unit includes two circulating pumps 9, a stock solution tank 10, a latex tube 7, an electroplating solution tank and a waste solution tank 8. The electroplating solution is contained in the stock solution tank 10, and the circulating pump 9 is used to draw the electroplating solution from the stock solution tank 10 at a set flow rate, and then the electroplating solution is sent to the sputtering head 2 through the latex tube 7. The electroplating solution is ejected from the sputtering head 2, and after contacting the cathode plate, the electroplating solution falls into the electroplating solution tank, and is then pumped by another circulating pump 9 to the waste solution tank 8. The electroplating solution in the waste solution tank 8 can be used as the electroplating stock solution after being re-dispensed.

[0038] The power supply forms a current loop through the anode wire 1 and the cathode plate, and applies current and voltage to the electroplating solution, so as to generate an electrodeposited layer in the contact area of the jet flow and the cathode plate. By controlling the current, voltage, distance between the anode wire 1 and the cathode plate and other parameters, the deposition rate can be controlled.

[0039] The plastic deformation module is used to apply a force to the deposited layer after the jet flow deposition, so that the deposited layer is plastically deformed. The plastic deformation module can be integrated with the sputtering head 2, or can be independently arranged.

[0040] The plastic deformation module includes an execution unit, a clamping unit and a driving unit. The clamping unit is used to install the execution unit, and the driving unit is used to control the movement of the execution unit. The execution unit can be in various forms such as a rolling mill 4 (as shown in Figure 2 ), a plane torsion head 16 (as shown in Figure 5 ) and an impact punch 17 (as shown in Figure 6 ).

[0041] In this embodiment, the plastic deformation module is integrated with the sputtering head 2, and moves with the sputtering head 2. The execution unit is taken as an example of the rolling mill 4 to describe the structure of the plastic deformation module in detail. The surface of the rolling mill 4 is provided with a pre-set hollow pattern 18. When rolling, the deposited layer in the hollow part is not controlled by pressure and grows freely, so that coarse grains are formed. Therefore, the size distribution of the grains in the deposited layer can be accurately controlled by changing the hollow pattern.

[0042] Figure 2 ​As shown, the clamping unit comprises a movable plate 19 and a spring 13, the movable plate 19 is provided with two left and right horizontal line limiting columns 3 in the horizontal direction and two vertical limiting columns 12 in the vertical direction, the spraying head shell 20 is provided with a rectangular cavity with an open lower end, two symmetrical sliding grooves are arranged on the left and right side walls of the rectangular cavity, two through holes are arranged on the upper end face, the movable plate 19 is slidably installed in the rectangular cavity, the two horizontal line limiting columns 3 extend into the two left and right symmetrical sliding grooves, and the two vertical limiting columns 12 extend into the two through holes of the upper end face. The upper end of the spring 13 abuts against the upper end face of the rectangular cavity, and the lower end of the spring 13 abuts against the movable plate 19. The roller 4 is horizontally installed below the movable plate 19 through a rotating shaft.

[0043] In the initial state, the roller 4 is not in contact with the cathode plate, and the spring 13 is in a free state. In work, the cathode table 6 is in contact with the roller 4, and when the Z-axis is adjusted to move the cathode table 6 upward, the cathode table 6 pushes the roller 4 to move upward, so as to compress the spring 13. The reaction force of the spring 13 forms the loading force of the plastic deformation module, and the size of the loading force can be obtained by converting the length of the vertical limiting column 12 extending out of the spraying head shell 20 and the elastic coefficient of the spring 13.

[0044] Similarly, for the plastic deformation module in the form of impact or torsion, the deformation loading force can be controlled by adjusting the position of the cathode table 6 up and down.

[0045] Based on the above-mentioned device for preparing heterogeneous nanostructure by deformation-assisted jet electro-deposition, the application further provides a method for preparing heterogeneous nanostructure by deformation-assisted jet electro-deposition. Figures 2-3 The plastic deformation module shown in the figure is taken as an example to illustrate the method in detail.

[0046] Embodiment one:

[0047] A method for preparing heterogeneous nanostructure by deformation-assisted jet electro-deposition, comprising the following steps:

[0048] (1) Build a deformation-assisted jet electro-deposition environment:

[0049] A 100*100*1mm nickel cathode plate is placed on the cathode table 6 and fixed with a clamp, and a negative electrode of a direct current power supply is connected. A circular spraying head 2 (with a diameter of 6mm) is fixed 3mm above the cathode plate, a nozzle pipe is arranged in the spraying head 2, an anode wire 1 is embedded in the spraying head 2, and a positive electrode of a direct current power supply is connected. The spraying head 2 is combined with the plastic deformation module, and the spraying head 2 is moved in the XY plane in a circular reciprocating manner by the three-dimensional moving platform 5.

[0050] The plastic deformation module is a roller 4, which is made of alumina ceramic drum with a diameter of 25 mm and a surface roughness of Ra 4.3 μm. The built-in spring 13 is selected with a spring coefficient K of 1 kN / m, and a scale is printed on the upright column of the movable plate 19. The spring applies a load of 1 N for each 1 mm upward lifting of the movable plate 19. The total weight of the movable plate 19, the roller and the spring is 1.2 N.

[0051] The electroplating solution for preparing the heterogeneous nano-structure copper is prepared by mixing 250 e / L of copper sulfate, 5-10 ml / L of concentrated sulfuric acid and deionized water to form a saturated copper sulfate solution.

[0052] (2) Power is turned on, and the electroplating solution is sprayed from the spraying head, and heterogeneous nano-structure ion reduction occurs in the area impacted by the jet flow to form a deposition layer.

[0053] Specifically, the direct current power supply is switched to a constant current mode to ensure that the current remains unchanged when the distance between the anode wire and the cathode plate changes, and the output current is maintained at 0.03 A, and the corresponding current density is 0.106 A / cm2. The output of the circulating pump 9 is adjusted to output the electroplating solution from the nozzle pipe to impact on the nickel cathode plate on the cathode platform, and then collect in the electroplating solution tank and be pumped by the inlet end of the circulating pump 9 to form a circulating flow. After power is turned on, copper ion reduction occurs in the area impacted by the jet flow to form a pure copper deposition layer. The thickness of a single deposition is about 10 nm. As the electroplating progresses, the copper ions are gradually consumed, and the originally saturated salt solution with a pH value of about 6-7 gradually becomes acidic, and the pH value decreases. The pH value of the electroplating solution is measured every 1 hour by a pH tester, and it is found that the pH value decreases to 3-4. Copper hydroxide is added to adjust the pH value to 6-7. Copper sulfate crystals are placed in the electroplating tank to replenish the consumption of copper ions at any time.

[0054] (3) The cathode plate is lifted to contact the roller 4 by controlling the three-dimensional moving platform 5, and then the cathode plate continues to rise to push the roller 4 upward together, driving the movable plate 19 to compress the built-in spring, thereby forming a load. The size of the load needs to be set in advance, for example, the load is set to 5 N at the initial stage of electrodeposition. As the thickness of the deposition layer increases, the load is gradually increased, and the maximum load is 20 N. The moving speed of the roller is set to 10 mm / s, and the reciprocating frequency is 6 times per minute.

[0055] (4) Steps (2)-(3) are repeatedly performed for layer-by-layer deposition and deformation, and the obtained sample after the equipment runs stably for 8 hours is shown in Figure 7 , the length of the deposited sample is 8 cm, the width is 6-8 mm, and the thickness is 150 μm (as shown in Figure 7 a). The microhardness test result is 2.0 GPa, and the sample surface is observed by laser confocal, and the structure is shown in Figure 7As shown in Fig. b, the sample is uniform and dense without obvious defects such as holes and inclusions. The cross section of the deposited sample is observed by scanning electron microscope (SEM) as shown in Fig. c, and it is found that the sample is mainly composed of nanocrystals and nanotwins, which proves the formation of nanostructured copper. Figure 7

[0056] Example 2:

[0057] A method for preparing heterogeneous nanostructure by deformation-assisted jet electro-deposition, comprising the following steps:

[0058] (1) The cathode plate (nickel plate) is fixed on the cathode table 6 after polishing, cleaning and hydrochloric acid activation, and a spraying head with two nozzle tubes is selected. The two nozzle tubes are connected to the respective independent electroplating liquid tanks after circulating pumps. The copper plating liquid formula is: 250 g of copper sulfate crystal is added to 1 L of deionized water to form a saturated copper sulfate solution; the nickel plating liquid formula is: 280 g / L of nickel sulfate, 40 g / L of nickel chloride, 45 g / L of boric acid, 2000.2 ml / L of brightener, and the rest is water.

[0059] In the initial state, the nozzle tube is placed 2 mm above the cathode plate. The plastic deformation module is a roller 4, and the movement connection mode is the same as above.

[0060] (2) When the device starts to run, the circulating pump connected to the first nozzle tube 14 is opened to output copper electroplating liquid, and the circulating pump connected to the second nozzle tube 15 is closed at the same time. The direct current power supply is in constant current mode, and the power output is kept at 0.05 A. The roller load is set to 5 N, the roller moving speed is 10 mm / s, and the reciprocating frequency is 6 times / min. At this time, a copper deposition layer is formed on the cathode plate, and the micro-roller reciprocates to cause plastic deformation of the copper deposition layer, thereby forming nanocrystals.

[0061] (3) After depositing copper for 5 minutes, the copper circulating pump is closed and the nickel circulating pump is opened. The output current is adjusted to 0.1 A, the speed and frequency of the plastic deformation module are kept unchanged, and the load is increased to 15 N. After continuing to run for 10 minutes, the nickel circulating pump is closed, the copper circulating pump is opened, and the output current and rolling load are adjusted accordingly. After alternating operation for 8 hours according to this mode, the device is turned off. Finally, a heterogeneous nano-composite structure of alternating arrangement of nanocrystalline copper / nanotwin nickel is formed.

[0062] It will be apparent to those skilled in the art that the present application can be varied in a number of ways, and such variations are not considered to be a departure from the scope of the application. All such modifications to persons skilled in the art will be included within the scope of the present claims.​

Claims

1. A method for preparing bulk heterogeneous nanostructures by deformation-assisted jet electrodeposition, characterized in that, Includes the following steps: Step 1: Set up the deformation-assisted jet electrodeposition environment, which includes: The plastic deformation module, the spraying head (2), and the cathode platform (6) are all mounted on the three-dimensional moving platform (5), so that the cathode platform (6) can move up and down along the Z-axis, and the plastic deformation module and the spraying head (2) can move along the X-axis and Y-axis, and the plastic deformation module and the spraying head (2) are positioned above the cathode platform (6); a cathode plate is clamped and fixed on the cathode platform (6), and the cathode plate is connected to the power cathode; the spraying head (2) includes a spraying head housing (20) and at least one nozzle tube, and an anode wire (1) is provided in the nozzle tube, and the anode wire (1) is connected to the power anode; the electroplating solution can be delivered to the spraying head (2) at a set flow rate through the electroplating solution circulation unit; Step 2: Turn on the power to spray the electroplating solution from the spray head (2), so that ion reduction occurs in the area impacted by the jet on the cathode plate surface, forming a deposition layer; the spray head (2) is equipped with two nozzle tubes, and the two nozzle tubes alternately spray two types of electroplating solution or solid microparticles to achieve alternating deposition of dissimilar metals; Step 3: Control the movement of the three-dimensional moving platform (5) so that the plastic deformation module contacts the cathode plate, and then apply a preset loading force to the deposition layer through the plastic deformation module to cause the deposition layer to undergo plastic deformation; Step 4: Repeat steps 2 to 3 to perform the layer-by-layer deposition of heterogeneous nanostructures. The plastic deformation module follows the movement path of the spray head (2) to deform each deposition layer layer by layer until the preparation of heterogeneous nanostructures is completed. The plastic deformation module includes a roller (4), which is integrated with the spraying head (2) via a movable plate (19) and a spring (13). In step three, the cathode plate is controlled to rise by a three-dimensional moving platform (5). When the cathode plate contacts the roller (4), it continues to rise, pushing the roller (4) upward to compress the spring (13) until the loading force of the spring (13) reaches the preset value, and then the upward movement of the cathode plate stops. After that, the roller (4) is controlled to reciprocate on the deposition layer. The surface of the roller (4) is pre-set with hollowed-out patterns. During rolling, the deposited layer in the hollowed-out area is not controlled by pressure and grows freely to form coarse crystals.

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