Method for preparing beryllium metal thin strip based on melt-spinning process

Abstract

The invention discloses a method for preparing a beryllium metal thin strip based on a melt-spinning process, and belongs to the technical field of metal thin strip preparation. The method for preparing the beryllium metal thin strip based on the melt-spinning technology comprises the steps that firstly, micro-nano texturing is conducted on the surface of a copper rotary roller in melt-spinning equipment; a composite coating is deposited on the surface of the micro-nano textured copper rotating roller, and surface modification of the copper rotating roller is completed; and then the beryllium metal thin strip is prepared according to a conventional melt-spinning method metal thin strip process. The thickness of the prepared beryllium metal thin strip is 30-40 [mu] m. According to the method, surface modification is carried out on the copper rotary roller of the melt-spinning equipment, so that the technical problem of adhesion of beryllium metal melt is effectively solved, and the high-quality micron-sized beryllium metal thin strip can be obtained. The invention provides a brand new beryllium metal thin strip preparation process which is simple to operate and can be popularized and applied on a large scale.

Description

Technical Field

[0001] This invention belongs to the field of metal strip preparation technology, specifically relating to a method for preparing beryllium metal strips based on a strip spinning process. Background Technology

[0002] Beryllium metal is widely used in the aerospace field due to its unique physical and chemical properties, mainly benefiting from its low density, high stiffness, good thermal stability, and excellent mechanical properties. Beryllium metal strips are used to manufacture structural components for aircraft and spacecraft, such as wing spars, satellite components, and mirrors for space telescopes.

[0003] Rolling technology is a commonly used method in the production of thin metal strips, offering advantages such as high production efficiency and high material utilization. Rolling technology enables continuous production, is highly efficient, and is suitable for large-scale production. It can achieve good surface finishes, reducing the need for subsequent processing. Material loss during rolling is minimal, resulting in high material utilization. However, rolling equipment typically requires significant investment, especially for precision rolling equipment. The rolling process demands high operational skills, requiring precise control of parameters such as rolling speed, temperature, and tension. For certain hard or brittle materials, such as beryllium, traditional rolling techniques may be difficult to apply directly. Moreover, in the rolling of ultra-thin strips, the mechanical properties of the material may undergo abnormal changes due to size effects, affecting product quality. While rolling technology is an efficient method for producing thin metal strips, it also has some limitations. For example, beryllium metal strips prepared using rolling technology are generally thicker than 0.6 mm, which cannot meet the thickness requirements of micron-sized beryllium metal strips.

[0004] Strip spinning is an advanced metal strip fabrication technology with numerous advantages, demonstrating significant strengths in practical applications. It utilizes high-speed centrifugal force to spin molten metal into thin strips, enabling the rapid production of large-area strips and significantly improving production efficiency. Compared to traditional casting and rolling processes, strip spinning eliminates multiple steps, achieving rapid solidification and shaping. The inert gas environment effectively prevents interference from oxygen and other impurities, resulting in extremely high purity metal strips. This is particularly important for applications requiring high-purity materials, such as semiconductors and aerospace. The rapid cooling and solidification of the metal strip during spinning effectively inhibits grain growth and the formation of harmful phases, resulting in fine-grained, high-quality metal strips. These strips typically exhibit excellent properties such as high strength, high conductivity, and high corrosion resistance. Furthermore, strip spinning offers high flexibility, suitable for preparing strips of various metals, including high-melting-point metals, refractory metals, and alloys. The process reduces energy consumption and waste generation, making it energy-efficient and environmentally friendly, aligning with green production principles. Vacuum spinning furnaces conduct the spinning process in a vacuum environment, reducing the possibility of oxidation and contamination.

[0005] In the melt spinning process, molten metal is sprayed at high speed onto the surface of a spinning roller for rapid cooling and shaping. Copper spinning rollers are widely used due to their high thermal conductivity; however, when preparing beryllium metal strips, the surface of the copper spinning roller is prone to wetting and adhesion with the molten beryllium metal, which can cause the following problems:

[0006] (1) Thin strips are difficult to peel off, resulting in tearing or uneven thickness;

[0007] (2) Residual melt accumulates on the roller surface, reducing the quality of subsequent belt spinning;

[0008] (3) Frequent shutdowns for cleaning reduce production efficiency.

[0009] Existing technologies improve adhesion by optimizing process parameters (such as roller speed and spraying pressure) or applying temporary release agents, but the former has limited effect and the latter is prone to contaminating the melt and requires continuous application. Summary of the Invention

[0010] To address the aforementioned problems encountered in preparing beryllium metal strips using the strip spinning technique, this invention provides a method for preparing beryllium metal strips based on the strip spinning process. By modifying the surface of the copper rotating rollers in the strip spinning equipment, not only is the problem of beryllium metal melt adhesion effectively solved, but the quality of the beryllium metal strip is also improved.

[0011] To achieve the above objectives, the present invention provides the following technical solution:

[0012] One of the technical solutions of this invention is to provide a method for preparing beryllium metal strips based on a strip spinning process, comprising the following steps:

[0013] First, the surface of the copper spinning roller in the strip spinning equipment is micro-nano textured; then, a composite coating is deposited on the micro-nano textured copper spinning roller surface to complete the surface modification of the copper spinning roller; then, beryllium metal strip is prepared according to the conventional strip spinning method for metal strips, and the thickness of the beryllium metal strip is 30~40μm.

[0014] The micro-nano structure parameters of the micro-nano texturing are: pit diameter 2~5μm, depth 5~10μm, pit spacing 5~10μm;

[0015] The composite coating comprises a transition layer, a functional layer, and a surface finishing layer bonded together in sequence, wherein the transition layer is in contact with the copper rotary roller;

[0016] The transition layer includes a titanium or chromium metal layer;

[0017] The functional layer includes a diamond-like carbon layer (DLC) or a silicon-doped diamond-like carbon layer (Si-DLC) with a hardness ≥2000HV;

[0018] The surface modification layer is a self-assembled monolayer of perfluoropolyether (PFPE).

[0019] In this invention, during the surface modification of copper rotary rollers, the stepped pits of the micro-nano structure trap air, forming an air cushion layer that reduces the actual contact area between the melt and the copper substrate, thereby lowering the adhesion force. A transition layer is deposited on the formed micro-nano structure to enhance the adhesion of the functional layer. The high-hardness functional layer is chemically inert, and together with the self-assembled perfluoropolyether monolayer on its surface, it synergistically inhibits the wetting of the beryllium metal melt.

[0020] This invention significantly improves the anti-sticking reliability of copper rollers by using multi-scale design of surface microengineering and nano-coatings, while ensuring the thermal conductivity of the copper rollers.

[0021] Preferably, the aspect ratio (depth / diameter) of the recess is ≤0.5.

[0022] The aspect ratio of the indentation helps to better prevent capillary penetration of molten beryllium metal.

[0023] Optionally, the micro-nano textured micro-nano structures are prepared by chemical etching, specifically using a mixed acid solution (H2O:HCl:HF = 15:4:1, volume ratio) for etching. The sample is placed in the mixed acid solution for etching for 15 minutes to obtain the stepped micro-nano structures.

[0024] Preferably, the thickness of the titanium or chromium metal layer is 50~200nm.

[0025] Preferably, the thickness of the diamond-like carbon layer is 0.5~1μm; the thickness of the silicon-doped diamond-like carbon layer is 0.5~1μm.

[0026] Preferably, the silicon content in the silicon-doped diamond-like carbon layer is 5-15 at.%.

[0027] Preferably, the thickness of the perfluoropolyether self-assembled monolayer is 1~10 nm.

[0028] Optionally, the transition layer is prepared by magnetron sputtering.

[0029] Optionally, the functional layer is prepared by plasma-enhanced chemical vapor deposition (PECVD).

[0030] Optionally, the perfluoropolyether self-assembled monolayer is prepared by an impregnation method, wherein the impregnation solution is a hydrofluoroether (HFE) solution of perfluoropolyether with a concentration of 0.1~1wt.%, and the perfluoropolyether self-assembled monolayer is obtained by curing at 150°C for 30 min after impregnation.

[0031] Preferably, the temperature of the beryllium metal melt in the belt spinning method is 1300~1800℃, and the rotation speed of the copper spinning roller is 1000~4000rpm.

[0032] The preferred process parameters of this invention are obtained based on Bayesian framework optimization.

[0033] The optimal operating temperature for the equipment is set to T. opt and stirring speed of N opt .

[0034] The specific steps are as follows:

[0035] (1) Parameter range setting: Based on the characteristics of the reactants and the safety limits of the equipment, set the temperature optimization range [T]. min ,T max ] and speed optimization range [N min , N max ].

[0036] (2) Optimization target definition: The comprehensive target is to maximize the product yield Y (%) and minimize the energy consumption per unit mass E (kWh / kg). The objective function is defined as F = w1 × Y - w2 × E, where w1 and w2 are preset weighting coefficients. Y is calculated by analysis of an online near-infrared spectrometer, and E is calculated by data from a power meter and a material scale.

[0037] (3) Initialization and modeling: K initial points (Ti, Ni) are randomly selected in the parameter space for experiments, and the corresponding Yi and Ei are recorded. Fi is calculated. A surrogate model based on the objective function F(T, N) of Gaussian process regression (GPR) is constructed using the initial dataset.

[0038] (4) Iterative optimization:

[0039] a. Based on the current GPR model, calculate the Acquisition Function(T, N).

[0040] b. Find candidate points (T) that maximize the acquisition function. candidate , N candidate ).

[0041] c. In (T) candidate , N candidate The equipment is run under these conditions to collect actual Y data. candidate E candidate Calculate F candidate .

[0042] d. Transfer the new data points (T) candidate , N candidate , F candidate Add to dataset.

[0043] e. Update the GPR agent model.

[0044] (5) Termination judgment: Repeat step (4) until either of the following conditions is met: a) the increase of F in m consecutive iterations is less than the threshold δF; b) the preset maximum number of experiments Max is reached. Trials .

[0045] Optimal parameter output and application: The point (T, N) corresponding to the highest F value in historical data when the termination condition is met is determined as the optimal parameter (T). opt , N opt The control system will T opt The set value is sent to the reactor temperature controller, and N opt The set values ​​are sent to the frequency converter of the mixing motor to enable the equipment to operate under optimal conditions.

[0046] Furthermore, online monitoring and re-optimization: During system operation, Y and E are continuously monitored. If their mean values ​​continue to deviate from the expected optimization value by more than the tolerance range Δ for a certain period of time, a new round of optimization processes (3) to (6) will be automatically triggered to adapt to changes in operating conditions.

[0047] The optimization process is executed by an optimization software module deployed on an industrial control computer. This module integrates a Bayesian optimization library and is connected to temperature sensors, speed sensors, power meters, online analyzers, and control actuators via a data acquisition card.

[0048] The beneficial technical effects of the present invention are as follows:

[0049] This invention, through surface modification of the copper rotating rollers in a strip spinning device, not only effectively solves the technical problem of beryllium metal melt adhesion but also enables the production of high-quality micron-sized beryllium metal strips. This invention provides a novel beryllium metal strip preparation process that is simple to operate and can be widely applied. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the preparation of beryllium metal strips using a strip spinning device according to the present invention.

[0051] Figure 2 This is a physical image of the beryllium metal strip prepared in Example 1 of the present invention.

[0052] Figure 3 The images shown are SEM images of the copper roller surface before and after etching with a mixed acid solution in Example 1 of the present invention, where (a) is before etching and (b) is after etching.

[0053] Figure 4 Simulation diagram of the copper roller surface before and after etching with mixed acid solution in Example 1 of this invention to wet metal droplets. Detailed Implementation

[0054] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0055] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0056] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0057] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.

[0058] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0059] Example 1

[0060] Beryllium metal strips were prepared using a strip spinning process.

[0061] (1) Surface modification of copper rotary rollers:

[0062] The surface of the copper rotary roller was polished to Ra≤0.1μm, then ultrasonically cleaned with acetone and dried; etching was performed using a mixed acid solution (H2O:HCl:HF=15:4:1, volume ratio). The sample was etched in a mixed acid solution for 15 min to obtain a copper rotary roller with a periodic stepped pit array on the surface. The parameters were: pit diameter 2~5 μm, pit depth 5~10 μm, pit spacing 5~10 μm; pit aspect ratio (depth / diameter) ≤0.5. A Ti transition layer (average thickness 100 nm) was deposited on the surface of the periodic micro-pit array using magnetron sputtering. Then, a DLC layer (hardness ≥2000 HV, average thickness 1 μm) was deposited on the Ti transition layer using PECVD. Finally, the copper rotary roller with the deposited DLC layer was immersed in a 0.5 wt% PFPE hydrofluoroether solution for 60 min. After removal, it was cured at 150 °C for 30 min to form a PFPE self-assembled monolayer (average thickness 50 nm) on the DLC layer, thus completing the surface modification of the copper rotary roller.

[0063] (2) Preparation of beryllium metal strips using a strip spinning machine:

[0064] Using beryllium metal blocks with a purity of over 99.99% as raw materials, beryllium metal strips are prepared in an argon atmosphere using a high-temperature spinning machine. The temperature of the high-temperature spinning machine is set to 1500℃; the rotation speed of the surface-modified copper spinning roller is set to 2000rpm. By running the equipment, beryllium metal strips can be obtained.

[0065] A schematic diagram of the fabrication of beryllium metal ribbons using a strip spinning device is shown below. Figure 1 .

[0066] A physical image of the beryllium metal strip prepared in Example 1 is shown below. Figure 2 .

[0067] SEM images of the copper roller surface before and after etching with the mixed acid solution in Example 1 are shown below. Figure 3 In this context, (a) represents the image before etching, and (b) represents the image after etching.

[0068] Molecular dynamics simulations were used to simulate the wetting and adhesion properties of molten metal droplets on smooth (before etching) and rough (after etching) surfaces. The simulation results are shown in [Figure number missing]. Figure 4 ( Figure 4 In the diagram, blue represents the state of metal droplets on rough surfaces, and red represents the state of metal droplets on smooth surfaces. Simulation results show that rough structures can reduce adhesion; droplets on rough surfaces are non-wetting and do not adhere easily.

[0069] Comparative Example 1

[0070] Beryllium metal strips were prepared using a strip spinning process.

[0071] Compared with Example 1, the processing steps of the periodic stepped pit array are omitted.

[0072] Comparative Example 2

[0073] Beryllium metal strips were prepared using a strip spinning process.

[0074] Compared with Example 1, the only difference is that the deposition step of the DLC layer is omitted.

[0075] The parameters of the beryllium metal strips prepared in Example 1 and Comparative Examples 1-2 are shown in Table 1.

[0076] Table 1. Parameters of each group of beryllium metal ribbons

[0077]

[0078] As can be seen from Table 1, by first preparing a periodic stepped pit array on a copper spinning roller and then composite a functional layer, the thickness of beryllium metal strip can be significantly reduced, thus improving the production quality of the strip.

[0079] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for producing a beryllium metal thin strip based on a capstoning process, characterized in that, The method comprises the following steps: First, the surface of a copper rotating roller in a spinning device is micro-nano textured; then a composite coating is deposited on the micro-nano textured surface of the copper rotating roller to complete the surface modification of the copper rotating roller; and then a beryllium metal thin strip is prepared according to the conventional process of a metal thin strip prepared by a spinning method, wherein the thickness of the beryllium metal thin strip is 30-40 μm; The micro-nano structure of the micro-nano texture is a periodic step pit array, and the parameters are as follows: pit diameter 2-5 μm, pit depth 5-10 μm, and pit spacing 5-10 μm; The composite coating comprises a transition layer, a functional layer and a surface modification layer which are sequentially combined, wherein the transition layer is in contact with the copper rotating roller; The transition layer comprises a titanium or chromium metal layer; The functional layer comprises a diamond-like carbon layer or a silicon-doped diamond-like carbon layer, and the hardness is greater than or equal to 2000 HV; The surface modification layer is a perfluoropolyether self-assembled monolayer.

2. The method of claim 1, wherein the method is characterized by: The aspect ratio of the pits is less than or equal to 0.

5.

3. The method of claim 1, wherein the method further comprises: The thickness of the titanium or chromium metal layer is 50-200 nm.

4. The method of claim 1, wherein the method is characterized by: The thickness of the diamond-like carbon layer is 0.5-1 μm, and the thickness of the silicon-doped diamond-like carbon layer is 0.5-1 μm.

5. The method of claim 1, wherein the method is characterized by: The content of silicon in the silicon-doped diamond-like carbon layer is 5-15 at.%.

6. The method of claim 1, wherein the method is characterized by: The thickness of the perfluoropolyether self-assembled monolayer is 1-10 nm.

7. The method of claim 1, wherein the method further comprises: The transition layer is prepared by a magnetron sputtering method.

8. The method of claim 1, wherein the method is characterized by: The functional layer is prepared by a plasma-enhanced chemical vapor deposition method.

9. The method of claim 1, wherein the method is characterized by: The perfluoropolyether self-assembled monolayer is prepared by an immersion method.

10. The method of claim 1, wherein the method is characterized by: In the spinning method, the temperature of the beryllium metal melt is 1300-1800 ℃, and the rotating speed of the copper rotating roller is 2000-4000 rpm.

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