A metal coating structure for plastic surface and its preparation method

Abstract

This application belongs to the field of plastic surface treatment technology. Embodiments of this application provide a metal coating structure for a plastic surface and its preparation method. The metal coating structure consists of, starting from the plastic surface, a PVD-plated base metal layer, a PVD-plated intermediate metal layer, a PVD-plated underlay metal layer, and an electroplated surface metal layer. The thickness of the electroplated surface metal layer is greater than the thickness of the PVD-plated underlay metal layer, and the PVD-plated underlay metal and the electroplated surface metal are the same metal. This application first utilizes the characteristics of PVD plating—fast deposition speed, low operating temperature, and minimal deformation of the plastic substrate—to deposit the first few metal layers onto the plastic substrate. Then, it utilizes the relatively simple electroplating process and the ability to avoid wasting precious metal materials with good conductor properties to achieve the surface metal layer plating. This increases the production capacity of waveguide antennas while effectively reducing the cost of waveguide antenna metallization processes, enabling mass production.

Description

Technical Field

[0001] This application relates to the field of plastic surface treatment technology, and in particular to a metal coating structure for plastic surfaces and a method for preparing the same. Background Technology

[0002] With the rapid development of the 5G era, millimeter-wave front-end communication systems play a pivotal role in the development of wireless networks.

[0003] Because millimeter-wave front-end communication requires a large operating bandwidth and suffers from significant atmospheric path loss, antennas used for communication transmission must possess high bandwidth, high efficiency, and high gain. Currently, large-scale array arrangements are commonly used to achieve low profile and high gain for millimeter-wave antennas. In terms of millimeter-wave antenna fabrication methods, existing technologies for producing large antenna arrays in the 20-140 GHz band still primarily employ metal substrate fabrication processes. This is because waveguide antennas based on metal substrates offer advantages such as low loss and wide bandwidth, avoiding losses caused by dielectric materials.

[0004] Because metal substrates are heavy—for example, when using metal substrates to produce dielectric substrates, and a waveguide antenna typically consists of multiple layers of dielectric substrates—the total weight of the metal dielectric substrate increases exponentially. Secondly, the processing technology for dielectric substrates based on metal substrates is long, complex, costly, and unsuitable for mass production. For these reasons, plastic materials are currently mostly used as the substrate for waveguide antennas. By metallizing the surface of the plastic, waveguide antenna assemblies can be obtained.

[0005] However, in the manufacturing process of waveguide antenna units, the metallization of the plastic surface accounts for the highest cost. Within the metal plating layer, the highest cost component is comprised of precious metals with good conductivity, such as silver, which can account for 60% to 80% of the total assembly cost. If silver plating is performed using only physical vacuum deposition (PVD), it is difficult to obtain a thick coating; furthermore, the metal diffusion in the PVD chamber causes significant material waste, resulting in very low utilization of the precious metal silver and a sharp increase in cost. Therefore, achieving lightweight waveguide antennas and low-cost, mass-producible waveguide antenna metallization processes are urgent technical problems that need to be solved. Summary of the Invention

[0006] This application provides a method for fabricating a metal coating structure on a plastic surface, which can improve the production capacity of waveguide antennas and reduce the cost of the waveguide antenna metallization process.

[0007] According to a first aspect of the embodiments of this application, a metal coating structure is provided on a plastic surface, wherein the plastic is used as a substrate for forming a waveguide antenna, and the metal coating structure consists of, starting from the plastic surface, a PVD-plated bottom metal layer, a PVD-plated intermediate metal layer, a PVD-plated base metal layer, and an electroplated surface metal layer; the thickness of the electroplated surface metal layer is greater than the thickness of the PVD-plated base metal layer, and the PVD-plated base metal and the electroplated surface metal are the same metal.

[0008] In one feasible implementation, the thickness of the PVD-plated bottom metal layer is 0.1 μm to 0.3 μm, the thickness of the PVD-plated intermediate metal layer is 1 μm to 3 μm, the thickness of the PVD-plated base metal layer is 0.1 μm to 0.3 μm, and the thickness of the electroplated surface metal layer is 1 μm to 5 μm.

[0009] In one feasible implementation, the metal coating structure further includes a PVD color layer, which is located outside the electroplated surface metal layer.

[0010] The thickness of the PVD color coating is 0.05μm to 0.1μm.

[0011] In one feasible implementation, the PVD-plated underlayer metal is titanium or chromium; the PVD-plated intermediate metal is copper or nickel; and the PVD-plated base metal and the electroplated surface metal are silver.

[0012] The plastic material is at least one of polyphenylene sulfide, polyetherimide, and polyetheretherketone.

[0013] According to a second aspect of the present application, a method for preparing a metal-plated structure on a plastic surface is provided, for preparing the metal-plated structure on a plastic surface as described in the above embodiments; the preparation method includes:

[0014] Provide a plastic substrate;

[0015] The plastic substrate is subjected to physical vapor deposition metallization to sequentially form a PVD-plated base metal layer, a PVD-plated intermediate metal layer, and a PVD-plated underlay metal layer on the surface of the plastic substrate, thereby obtaining a coated substrate.

[0016] Electroplating is performed on the coating substrate to form an electroplated surface metal layer on the exposed surface of the coating substrate.

[0017] The thickness of the electroplated surface metal layer is greater than the thickness of the PVD-plated base metal layer, and the PVD-plated base metal and the electroplated surface metal are the same metal.

[0018] In one feasible implementation, the preparation method further includes:

[0019] Physical vapor deposition metallization is performed on the substrate on which the electroplated surface metal layer is formed to form a PVD color layer on the surface of the electroplated surface metal layer.

[0020] The thickness of the PVD color coating layer is 0.05μm to 0.1μm.

[0021] In one feasible implementation, the thickness of the PVD-plated bottom metal layer is 0.1 μm to 0.3 μm, the thickness of the PVD-plated intermediate metal layer is 1 μm to 3 μm, the thickness of the PVD-plated base metal layer is 0.1 μm to 0.3 μm, and the thickness of the electroplated surface metal layer is 1 μm to 5 μm.

[0022] And / or, the material of the PVD-coated color layer is pure zirconium metal or pure titanium metal;

[0023] And / or, the plastic substrate is made of at least one of polyphenylene sulfide, polyetherimide, and polyetheretherketone.

[0024] In one feasible implementation, the physical vapor deposition metallization process includes vacuum sputtering.

[0025] The step of performing physical vapor deposition metallization on the plastic substrate includes:

[0026] A titanium or chromium metal layer is first deposited on the plastic substrate using the vacuum sputtering method, which serves as the bottom metal layer for the PVD plating.

[0027] Another copper or nickel metal layer is deposited as the intermediate metal layer for the PVD plating.

[0028] Finally, a silver metal layer is deposited as the base metal layer for the PVD plating.

[0029] In one feasible implementation, the step of electroplating the coating substrate includes:

[0030] Multiple electrolyte tanks are provided, and multiple plating substrates are simultaneously introduced into the electrolyte tanks to deposit a silver metal layer on the plating substrates as the electroplated surface metal layer;

[0031] The plating solution in the electrolyte tank includes cationic, anionic, or nonionic surfactants.

[0032] In one feasible implementation, prior to the step of physical vapor deposition metallization of the plastic substrate, the following steps are included:

[0033] The surface of the plastic substrate is ultrasonically cleaned to remove oil stains, and then the plastic substrate is dried.

[0034] This application provides a plastic surface metal coating structure and its preparation method. First, a bottom metal layer, an intermediate metal layer, and a base metal layer are sequentially deposited on a plastic substrate using PVD deposition. Then, a surface metal layer of the same material as the base metal layer and with good conductivity is achieved through electroplating. PVD deposition leverages its advantages of fast deposition speed, low operating temperature, and minimal risk of deformation of the plastic substrate to deposit the first few metal layers onto the substrate. Electroplating, with its relatively simple process and ability to avoid wasting precious metal materials with good conductive properties, is then used to deposit the surface metal layer. This improves waveguide antenna production capacity while effectively reducing the cost of waveguide antenna metallization processes, enabling mass production. Attached Figure Description

[0035] Figure 1 This is one of the overall structural schematic diagrams of the metal coating structure on the plastic surface provided in the embodiments of this application;

[0036] Figure 2 This is the second overall structural schematic diagram of the metal coating structure on the plastic surface provided in the embodiments of this application;

[0037] Figure 3 This is one of the schematic flowcharts of the method for preparing a metal coating structure on a plastic surface provided in the embodiments of this application;

[0038] Figure 4 This is the second schematic diagram of the process for preparing a metal coating structure on a plastic surface provided in the embodiments of this application.

[0039] Explanation of reference numerals in the attached figures:

[0040] 100. Plastic; 200. PVD-plated base metal layer; 300. PVD-plated intermediate metal layer; 400. PVD-plated base metal layer; 500. Electroplated surface metal layer; 600. PVD-plated color layer. Detailed Implementation

[0041] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of this application.

[0042] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0043] In the manufacturing process of waveguide antenna units, surface metallization of the plastic is required. This surface metallization accounts for the highest cost of the entire waveguide antenna manufacturing process. Among the metal coatings, the highest cost is comprised of precious metals with good conductivity, such as silver, which can account for 60% to 80% of the total cost. However, if silver is plated using only physical vacuum deposition (PVD) technology, it is difficult to obtain a thick coating. Furthermore, the material waste caused by metal diffusion in the PVD chamber is significant, resulting in very low utilization of the precious metal silver and a sharp increase in cost.

[0044] To address the aforementioned problems, this application provides a metal coating structure for a plastic surface and a method for preparing the same. To facilitate understanding of the technical solutions in this application, some concepts involved in this application will first be explained below.

[0045] Metallization of plastic surfaces refers to the process of applying one or more layers of metal to the surface of plastic using physical or chemical methods, giving the surface certain metallic properties, such as electrical conductivity, magnetism, and thermal conductivity. Metallized plastics have a metallic appearance, high hardness, and are lightweight; they also possess high toughness, high heat resistance, and high corrosion resistance.

[0046] Coating processes generally include Physical Vapor Deposition (PVD) and electroplating. PVD can be further divided into vacuum evaporation and magnetron sputtering. Vacuum evaporation involves heating the coating material in a vacuum environment, causing it to evaporate in a very short time and deposit onto the plastic surface to form a coating. Magnetron sputtering uses high-energy ions to bombard a target, causing the atoms on the target surface to gain sufficient energy to detach from the substrate and fly out in a corresponding sputtering direction, depositing onto the plastic surface. Electroplating, on the other hand, is an electrochemical process in which the plastic substrate is immersed in a solution of metal salts as the cathode, and a metal plate, such as a silver plate, as the anode. After connecting to a DC power supply, the desired coating is deposited on the plastic substrate.

[0047] However, both PVD plating and electroplating have their advantages and disadvantages. For example, the metallic texture of PVD plating cannot compare with that of electroplating; electroplating colors are relatively limited, generally only a few such as bright silver, matte silver, black chrome, antique red, and antique nickel, while PVD plating can achieve a range of colors; electroplating requires a higher product structure and special plating mounting positions, while PVD plating does not; electroplating can be reworked and re-plated, but PVD plating cannot, resulting in high waste rates for PVD plating.

[0048] More specifically, PVD plating is limited by the capacity of the equipment cavity. For example, as the thickness of the outer silver layer increases from 0.1μm to 2μm, the plating time of the workpiece in the cavity increases from 1 hour to 4 hours. This occupies too much time on the PVD production line, resulting in a sharp drop in capacity. Moreover, the space in the PVD equipment cavity is limited, and the amount that can be loaded each time is also limited, which further restricts the capacity.

[0049] Figure 1 This is a schematic diagram of the overall structure of the metal coating on the surface of the plastic 100 provided in the embodiments of this application.

[0050] Reference Figure 1 As shown, this application embodiment provides a metal coating structure on the surface of a plastic 100. The plastic 100 is used to form the substrate of a waveguide antenna. The metal coating structure consists of a PVD-plated bottom metal layer 200, a PVD-plated intermediate metal layer 300, a PVD-plated base metal layer 400, and an electroplated surface metal layer 500, starting from the surface of the plastic 100. The thickness of the electroplated surface metal layer 500 is greater than the thickness of the PVD-plated base metal layer 400, and the PVD-plated base metal and the electroplated surface metal are the same metal.

[0051] Understandably, PVD plating is chosen for its fast deposition rate, low operating temperature, and low risk of deformation of the plastic 100 substrate. It also offers greater flexibility in material selection. Therefore, PVD plating is used for depositing the base metal layer, intermediate metal layer, and undercoat metal layer on the plastic 100 surface. This can be compared to electroplating in terms of material selection. As a non-conductor, plastic 100 requires a conductive layer before electroplating. Forming this conductive layer involves several steps, including roughening, neutralization, sensitization, activation, and chemical plating, making it much more complex than metal electroplating and prone to problems during production. Furthermore, not all plastic 100 is suitable for electroplating. Currently, ABS (Acrylonitrile Butadiene Styrene) is the most commonly used material for plastic 100 electroplating, followed by PP (Polypropylene). Currently, only ABS, polycarbonate (PC), polypropylene (PP), polysulfone (PSF), nylon (PA), and polystyrene (PS) can be electroplated with metal layers. While there are successful electroplating methods for PC, PSF, and PTFE (Polytetrafluoroethylene), they are more difficult. Some plastics (Plastic 100) have very poor adhesion to metal layers, rendering them impractical; others have significant differences in physical properties, such as the coefficient of thermal expansion, with metal plating. Because waveguide antenna manufacturing involves high-temperature reflow soldering, the high-temperature environment makes it difficult to guarantee performance. From the above analysis, it is clear that electroplating metal layers onto Plastic 100 substrates is highly limiting and cumbersome.

[0052] The plastic 100 and its surface metal coating structure in this embodiment are used as waveguide antenna components. A key characteristic of waveguide antennas is that microwaves propagate along the surface of the waveguide and in the surrounding space, largely independent of the waveguide's material. Therefore, the waveguide can be made from inexpensive, lightweight, and easily processed materials (such as plastic 100), and only a coating beneficial to radio wave transmission needs to be applied to the surface. Both gold and silver have excellent electrical conductivity, which not only improves conductive contact impedance but also enhances signal transmission. Since gold is more expensive, the coating of the waveguide antenna is primarily silver. As a precious metal, the thickness of the silver coating directly affects the cost of the waveguide antenna product.

[0053] The PVD-plated base metal and the electroplated surface metal are the same metal; in one example, both are silver. The thickness of the PVD-plated base metal layer 400 is 0.1 μm to 0.3 μm, and the thickness of the electroplated surface metal layer 500 is 1 μm to 5 μm. It is understandable that the PVD-plated base metal layer 400 and the electroplated surface metal layer 500, as coatings on the surface of the plastic 100, are thicker than the bottom and middle metal layers. If PVD plating were used alone, it would not only increase the time and reduce production capacity but also result in a significant waste of silver, which is detrimental to cost control. Therefore, in this embodiment, the advantage of the fast deposition rate of PVD plating is first utilized to perform a silver base plating on the outer side of the middle metal layer. The thickness of this silver plating layer is much smaller than the required silver plating thickness for the waveguide antenna. The thickness of the silver plating in this area can be 0.1μm, 0.15μm, 0.2μm, 0.25μm, or 0.3μm. The specific thickness can be set according to the model of the PVD equipment used, and no specific limit is made here.

[0054] Furthermore, PVD has inherent drawbacks, namely, long silver plating time, difficulty in obtaining thick coatings, and significant silver material waste due to metal diffusion in PVD equipment. Therefore, after depositing a base silver layer via PVD, electroplating is used to prepare the surface metal layer. Electroplating is simpler, with less demanding equipment and environment compared to PVD plating. Moreover, electroplating avoids silver material waste, saving costs. In this embodiment, electroplating is only used when preparing a thicker silver layer on the plastic 100 surface, thus avoiding electroplating processes such as hydrophilic treatment, roughening, neutralization, palladium water treatment, and desizing, greatly reducing the generation of highly polluting exhaust gases and wastewater. The thickness of the silver plating can be 1μm, 2μm, 3μm, 4μm, 5μm, etc., and the specific thickness is not limited here.

[0055] The reason for preparing the thin silver undercoat and thick silver topcoat separately also includes preventing a displacement reaction between silver and the intermediate metal layer during electroplating, which would affect the adhesion of the plating. Specifically, the standard electrode potential of silver (at 25°C, relative to the standard hydrogen electrode, Ag / Ag+) is +0.799V. Therefore, silver plating is a cathodic plating on most metal substrates, and appropriate measures must be taken to prevent the formation of displacement plating layers when electroplating on these materials. Because silver has a very positive electrode potential, except for a very few metals with a more positive potential such as gold and platinum, most other metals such as copper, aluminum, iron, nickel, and tin (intermediate metal layer) will undergo a displacement reaction during silver plating due to silver's positive potential, causing problems with the adhesion of the plating layer. To prevent this displacement plating process that affects the adhesion of the plating layer, pre-plating is generally used before the formal silver plating. This type of pre-plating solution requires a high cyanide content and a very low silver ion concentration. Combined with charging during the plating process, this results in a thin silver layer being pre-plated, thus preventing the displacement plating process. If the traditional pre-plating method is used, a specific concentration of cyanide and anion solutions must be prepared and contained in a solution tank, requiring considerable space and involving a cumbersome preparation process.

[0056] In some embodiments, the PVD-plated underlayer metal is titanium or chromium, and the thickness of the PVD-plated underlayer metal layer 200 is 0.1 μm to 0.3 μm. It is understood that titanium and chromium have high strength and corrosion resistance. Directly PVD-plating them onto the outer surface of the plastic 100 can significantly improve the strength, hardness, and wear resistance of the workpiece, and also enable the hardened surface layer to achieve high stability, facilitating the subsequent PVD plating of the intermediate metal layer. Specifically, the thickness of the PVD-plated metal layer can be 0.1 μm, 0.15 μm, 0.2 μm, 0.25 μm, or 0.3 μm; the specific thickness is not limited here.

[0057] In some embodiments, the PVD-plated intermediate metal is copper or nickel, and the thickness of the PVD-plated intermediate metal layer 300 is 1 μm to 3 μm. It is understood that the PVD intermediate metal layer can be made of nickel, which, being beneath the silver layer, provides high-temperature resistance. Specifically, the thickness of the PVD-plated intermediate metal layer 300 can be 1 μm, 1.5 μm, or 3 μm; the specific thickness is not limited here.

[0058] The aforementioned titanium or chromium layers, or copper or nickel layers, are all achieved using PVD plating, which avoids the problems of high water consumption and significant pollution associated with electroplating. Furthermore, it saves costs. Specifically, traditional electroplating processes for copper, nickel, etc., require hydrophilic treatment, roughening, neutralization, palladium water treatment, and desizing, among other steps. Since electroplating is a highly polluting industry, it consumes a large amount of water, incurs higher wastewater treatment costs, and involves a variety of added chemicals, which is detrimental to the utilization and protection of water resources and the environment. Moreover, the presence of chemical nickel layers, single or multiple nickel layers, and hexavalent chromium layers in this structure not only poses risks of nickel allergy, but hexavalent chromium is also highly toxic and carcinogenic, and wastewater treatment costs are high.

[0059] Figure 2 This is the second overall structural schematic diagram of the metal coating structure on the plastic surface provided in the embodiments of this application.

[0060] Reference Figure 2 As shown, in some embodiments, the metal coating structure further includes a PVD color layer 600, which is located outside the electroplated surface metal layer 500; the thickness of the PVD color layer 600 is 0.05μm to 0.1μm.

[0061] Understandably, electroplating processes limit the variety of colors available for workpieces, resulting in a relatively monotonous color palette. Commonly used colors include matte silver, gray silver, gunmetal, gold, black chrome, and semi-gloss chrome. To achieve greater color diversity, PVD plating is employed, enabling the deposition of a wide range of colors, including shimmering silver, magic blue, crackle finish, and waterdrop silver. Specifically, the thickness of the PVD plating color layer 600 can be 0.05μm, 0.07μm, 0.09μm, 0.1μm, etc., without further limitation.

[0062] Here are some common PVD coating color configurations: Chromium + Methane: light and dark black; Chromium + Nitrogen: light black; Chromium + Nitrogen + Methane: silver-gray; Chromium + Oxygen: light yellow, purple, green. Alternatively, Titanium + Oxygen: seven-color optical film; Titanium + Methane: light and dark black; Titanium + Nitrogen: imitation gold, brass; purple, red; Titanium + Nitrogen + Methane: imitation rose gold, black-green, vintage yellow, brown, purple. When the oxygen content reaches a certain level, the color of the film changes with the film thickness. Taking titanium oxide as an example, the following table shows:

[0063] Titanium oxide film thickness 0.400μm 0.43μm 0.47μm 0.53μm 0.58μm color Purple light blue blue green yellow

[0064] In some embodiments, the material of plastic 100 is at least one of polyphenylene sulfide, polyetherimide, and polyetheretherketone.

[0065] Understandably, the options include polyphenylene sulfide (PPS), polyetherimide (PEI), and poly(ether-ether-ketone) PEEK. Since Plastic 100 must withstand reflow soldering at 220℃, the choice is limited to PPS, PEI, and PEEK, which have high heat distortion temperatures. Furthermore, the poor adhesion between PPS / PEI and electroplated chromium / titanium makes substrate electroplating extremely difficult; and the significant difference in physical properties between PPS / PEI and the metal plating, such as their coefficients of thermal expansion, makes it difficult to ensure plating stability in high-temperature environments.

[0066] Using PVD to deposit metal layers effectively solves the aforementioned problems because PVD lines have their own plasma cleaning process, and PVD can be used to deposit metal layers on almost all plastic substrates.

[0067] This application also provides a method for preparing a metal coating structure on the surface of plastic 100, such as... Figure 3 and Figure 4 As shown, this preparation method is mainly used to prepare the metal coating structure on the surface of plastic 100 in the above embodiments. The preparation method may include:

[0068] Step S101: Provide a plastic substrate;

[0069] It is understood that the preparation process of the plastic 100 substrate can be understood based on relevant technologies, and will not be elaborated here. The plastic 100 substrate provided here is a molded part.

[0070] Step S102: Physical vapor deposition metallization is performed on the plastic 100 substrate to sequentially form a PVD-plated bottom metal layer 200, a PVD-plated intermediate metal layer 300 and a PVD-plated base metal layer 400 on the surface of the plastic 100 substrate, and a coated substrate is obtained.

[0071] Understandably, due to the fast deposition rate and low operating temperature of PVD plating, which minimizes deformation of the plastic 100 substrate and offers great flexibility in material selection, the PVD plating process is used for depositing the bottom metal layer, intermediate metal layer, and base metal layer on the surface of the plastic 100. The plating of the waveguide antenna is mainly silver plating. Silver has excellent conductivity, which not only improves the conductive contact impedance but also enhances signal transmission. In this embodiment, the advantage of the fast deposition rate of PVD plating is first utilized to perform silver plating as a base layer on the outside of the intermediate metal layer. The thickness of the silver plating layer at this location is much smaller than the required silver plating thickness for the waveguide antenna.

[0072] Step S103: Electroplating is performed on the coating substrate to form an electroplated surface metal layer 500 on the exposed surface of the coating substrate; wherein the thickness of the electroplated surface metal layer 500 is greater than the thickness of the PVD-plated base metal layer 400, and the PVD-plated base metal and the electroplated surface metal are the same metal.

[0073] Understandably, PVD has inherent drawbacks, namely, long silver plating time, difficulty in obtaining thick coatings, and significant silver material waste due to metal diffusion in PVD equipment. Therefore, after depositing a base silver layer using PVD, electroplating is used to prepare the surface metal layer. This is advantageous because electroplating is a simpler process, requiring less stringent equipment and environment compared to PVD plating. Furthermore, electroplating avoids silver material waste, saving costs. In this embodiment, electroplating is only used when preparing a thicker silver layer on the plastic 100 surface, thus avoiding the hydrophilic, roughening, neutralization, palladium water, and desizing electroplating processes, significantly reducing the generation of highly polluting exhaust gases and wastewater.

[0074] In some embodiments, the preparation method may include: step S104, performing physical vapor deposition metallization on the plating substrate on which the electroplated surface metal layer 500 is formed, so as to form a PVD color layer 600 on the surface of the electroplated surface metal layer 500; wherein the thickness of the PVD color layer 600 is 0.05 μm to 0.1 μm.

[0075] PVD plating allows for a variety of workpiece appearance colors. In one example, the PVD plating color layer 600 is made of pure zirconium or pure titanium. Zirconium, used for decoration, enhances the workpiece's color and significantly improves its strength, hardness, and wear resistance, while also providing high chemical stability to the material surface. The specific color types and thicknesses of the PVD plating color layer 600 are explained in the above embodiments and will not be repeated here.

[0076] In some embodiments, the thickness of the PVD-plated bottom metal layer 200 is 0.1 μm to 0.3 μm, the thickness of the PVD-plated intermediate metal layer 300 is 1 μm to 3 μm, the thickness of the PVD-plated base metal layer 400 is 0.1 μm to 0.3 μm, and the thickness of the electroplated surface metal layer 500 is 1 μm to 5 μm. The specific thicknesses of the PVD-plated bottom metal layer 200, PVD-plated intermediate metal layer 300, PVD-plated base metal layer 400, and electroplated surface metal layer 500 can be determined with reference to the above embodiments, but the specific thickness needs to be set according to the actual manufacturing process, and no specific limitations are imposed here.

[0077] In some embodiments, the material of the plastic 100 substrate is at least one of polyphenylene sulfide, polyetherimide, and polyetheretherketone. The selection of the plastic 100 substrate can be made with reference to the above embodiments so that the plastic 100 substrate has high temperature resistance, which will not be repeated here.

[0078] In some embodiments, physical vapor deposition metallization processes include vacuum sputtering. Vacuum sputtering involves argon gas undergoing glow discharge under vacuum conditions filled with argon (Ar) gas. Argon (Ar) atoms are ionized into argon ions (Ar+). Under the influence of an electric field, the argon ions accelerate and bombard a cathode target made of a metal plating material. The target material is sputtered out and deposited onto the surface of the workpiece. More specific process flows can be understood by referring to relevant technologies, and will not be elaborated here.

[0079] Step S102 further includes: step S1021, depositing a titanium metal layer or a chromium metal layer on the plastic 100 substrate using vacuum sputtering as the PVD plating bottom metal layer 200; step S1022, depositing a copper metal layer or a nickel metal layer as the PVD plating intermediate metal layer 300; and step S1023, finally depositing a silver metal layer as the PVD plating base metal layer 400.

[0080] Understandably, titanium and chromium possess high strength and corrosion resistance. Directly deposited onto the outer surface of plastic 100 via PVD significantly improves the workpiece's strength, hardness, and wear resistance. Furthermore, it ensures high stability of the hardened surface layer, facilitating subsequent PVD deposition of the intermediate metal layer. Nickel, positioned beneath the silver layer, provides high-temperature resistance. Leveraging the rapid deposition rate of PVD, a silver undercoat is applied to the outer side of the intermediate metal layer. The thickness of this silver layer is significantly less than that required for the waveguide antenna, thus providing a foundation for the subsequent electroplating of a thicker silver layer.

[0081] Step S103 further includes step S1031, providing multiple electrolyte tanks and simultaneously introducing multiple plating substrates into the electrolyte tanks to deposit a silver metal layer on the plating substrates as the electroplated surface metal layer 500; wherein the plating solution in the electrolyte tanks includes cationic, anionic or nonionic surfactants.

[0082] It is understood that in this embodiment, multiple plating substrates are used as cathodes, and a pure silver plate is used as an anode. These are introduced in parallel into multiple electrolyte baths containing silver nitrate and potassium cyanide, thereby plating a silver layer of a predetermined thickness onto the plating substrate. This not only avoids wasting silver material but also allows for the simultaneous plating of multiple plastic 100-ton substrates, significantly increasing production capacity. Furthermore, cationic, anionic, or nonionic surfactants can be added to the plating solution to improve its performance. If the surface metal layer is an appearance layer, brighteners or semi-bright crystals can be added to the plating solution to improve the glossy appearance of the plating layer.

[0083] Before step S102, the procedure includes step S1011, which involves ultrasonically cleaning the surface of the plastic 100 substrate to remove oil stains, and then drying the plastic 100 substrate. It is understood that pretreatment of the plastic 100 substrate is necessary before PVD plating. Various pretreatment methods are available, including ultrasonic cleaning to remove oil stains from the surface of the plastic 100 substrate, followed by drying before use. However, the pretreatment method is not limited.

[0084] The waveguide antenna fabricated using the method for preparing the metal coating structure on the surface of plastic 100 provided in this embodiment has a bonding strength test of greater than or equal to 5B.

[0085] In this embodiment, a bottom metal layer, an intermediate metal layer, and a base metal layer are sequentially deposited on a plastic 100 substrate using PVD deposition. Then, a surface metal layer, made of the same material as the base metal layer and possessing good conductivity, is deposited using electroplating. This method leverages the advantages of PVD deposition—fast deposition speed, low operating temperature, and minimal risk of deformation of the plastic 100 substrate—to deposit the first few metal layers onto the substrate. Then, the relatively simple electroplating process, which avoids wasting precious metal materials with good conductive properties, is used to deposit the surface metal layer. This increases waveguide antenna production capacity while effectively reducing the cost of waveguide antenna metallization processes, enabling mass production.

[0086] It is readily understood that, based on the several embodiments provided in this application, those skilled in the art can combine, split, or reorganize the embodiments of this application to obtain other embodiments, none of which exceed the protection scope of this application.

[0087] The above detailed embodiments further illustrate the purpose, technical solution, and beneficial effects of the embodiments of this application. It should be understood that the above are merely specific embodiments of the embodiments of this application and are not intended to limit the protection scope of the embodiments of this application. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solutions of the embodiments of this application should be included within the protection scope of the embodiments of this application.

Claims

1. A plastic surface metal plated structure, characterized by, The plastic (100) is used to form a base body of a waveguide antenna, and the metal coating structure comprises, in sequence from the surface of the plastic (100), a PVD plated bottom metal layer (200), a PVD plated intermediate metal layer (300), a PVD plated base metal layer (400) and an electroplated surface metal layer (500); the thickness of the electroplated surface metal layer (500) is greater than the thickness of the PVD plated base metal layer (400), and the PVD plated base metal and the electroplated surface metal are the same kind of metal; The thickness of the PVD plated bottom metal layer (200) is 0.1-0.3 μm, the thickness of the PVD plated intermediate metal layer (300) is 1-3 μm, the thickness of the PVD plated base metal layer (400) is 0.1-0.3 μm, and the thickness of the electroplated surface metal layer (500) is 1-5 μm; The PVD plated bottom metal is titanium or chromium, the PVD plated intermediate metal is copper or nickel, and the PVD plated base metal and the electroplated surface metal are silver.

2. The plastic surface metal plated structure according to claim 1, wherein, The metal coating structure further comprises a PVD plated color layer (600) located outside the electroplated surface metal layer (500). The thickness of the PVD plated color layer (600) is 0.05-0.1 μm.

3. The plastic surface metal plated structure of claim 1, wherein, The plastic (100) is made of at least one of polyphenylene sulfide, polyetherimide and polyether ether ketone.

4. A method for preparing a plastic surface metal plated structure, characterized by, The method for preparing the surface metal coating structure of the plastic (100) according to any one of claims 1-3 comprises the following steps: providing a plastic (100) base material; carrying out physical vapor deposition metallization on the plastic (100) base material to form, in sequence, a PVD plated bottom metal layer (200), a PVD plated intermediate metal layer (300) and a PVD plated base metal layer (400) on the surface of the plastic (100) base material, and obtaining a coating base material; carrying out electroplating on the coating base material to form an electroplated surface metal layer (500) on the exposed surface of the coating base material; wherein the thickness of the electroplated surface metal layer (500) is greater than the thickness of the PVD plated base metal layer (400), and the PVD plated base metal and the electroplated surface metal are the same kind of metal.

5. The method of claim 4, wherein the metal plating layer is formed by electroplating. 5 The method further comprises the following steps: carrying out physical vapor deposition metallization on the coating base material with the electroplated surface metal layer (500) to form a PVD plated color layer (600) on the surface of the electroplated surface metal layer (500); wherein the thickness of the PVD plated color layer (600) is 0.05-0.1 μm.

6. The method of claim 5, wherein the method further comprises the step of: The thickness of the PVD plated bottom metal layer (200) is 0.1-0.3 μm, the thickness of the PVD plated intermediate metal layer (300) is 1-3 μm, the thickness of the PVD plated base metal layer (400) is 0.1-0.3 μm, and the thickness of the electroplated surface metal layer (500) is 1-5 μm; ​ and / or, the material of the PVD plated color layer (600) is pure zirconium metal or pure titanium metal; And / or, the material of the plastic (100) substrate is at least one of polyphenylene sulfide, polyetherimide, polyether ether ketone.

7. The method of claim 4, 5 or 6, wherein the method further comprises the step of: The physical vapor deposition metallization process includes a vacuum sputtering method. ​ The step of performing physical vapor deposition metallization on the plastic (100) substrate includes: A layer of titanium metal or chromium metal is first deposited on the plastic (100) substrate by the vacuum sputtering method, as the PVD bottom metal layer (200); Then a layer of copper metal or nickel metal is deposited, as the PVD intermediate metal layer (300); Finally, a layer of silver metal is deposited, as the PVD bottom metal layer (400).

8. The method of claim 4, 5 or 6, wherein the method further comprises the step of: The step of electroplating the plated layer substrate includes: ​ Multiple electrolyte tanks are provided, and multiple plated layer substrates are simultaneously introduced into the electrolyte tanks to deposit a layer of silver metal on the plated layer substrate as the electroplated surface metal layer (500). The plating solution in the electrolyte tank includes cationic, anionic or non-ionic surfactants.

9. The method of claim 4, 5 or 6, wherein the method further comprises the step of: Before the step of performing physical vapor deposition metallization on the plastic (100) substrate, it includes: ​ The surface of the plastic (100) substrate is ultrasonically cleaned to remove oil stains on the surface of the plastic (100) substrate, and the plastic (100) substrate is subjected to a drying treatment.

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