Magnesium alloy structural part and machining method thereof

Abstract

The invention discloses a magnesium alloy structural part and a processing method thereof, and relates to the technical field of magnesium alloy surface treatment.The magnesium alloy structural part comprises a structural part base body and a graphene coating arranged on the surface of the structural part base body, the graphene coating comprises graphene, a binder and a silane coupling agent, the mass ratio of the graphene to the binder to the silane coupling agent is (2-25): (30-50): (0.2-5). According to the technical scheme, the corrosion resistance of the magnesium alloy structural part can be improved, and the quality requirement of the electroplating technology is met.

Description

Technical Field

[0001] This invention relates to the field of magnesium alloy surface treatment technology, and in particular to a magnesium alloy structural component and its processing method. Background Technology

[0002] Magnesium alloys, due to their low density, high specific strength, and high specific stiffness, have seen increasing applications in smart wearable products in recent years to meet the dual demands of high strength and lightweight design. However, magnesium alloys have extremely poor corrosion resistance. Direct electroplating without surface treatment easily leads to uneven plating, missed plating, and insufficient adhesion, making it difficult to meet the quality requirements of the electroplating process. Summary of the Invention

[0003] The main objective of this invention is to propose a magnesium alloy structural component and its processing method, aiming to improve the corrosion resistance of the magnesium alloy structural component and meet the quality requirements of the electroplating process.

[0004] To achieve the above objectives, the present invention proposes a magnesium alloy structural component, the magnesium alloy structural component comprising a structural component substrate and a graphene coating disposed on the surface of the structural component substrate, the graphene coating comprising graphene, a binder and a silane coupling agent; wherein the mass ratio of the graphene, the binder and the silane coupling agent is (2-25):(30-50):(0.2-5).

[0005] In one embodiment, the graphene has 1-5 layers; and / or the graphene has a particle size of 5μm-30μm.

[0006] In one embodiment, the adhesive comprises styrene-butadiene rubber and / or acrylic acid.

[0007] In one embodiment, the thickness of the graphene coating is 1 μm-3 μm.

[0008] In one embodiment, the magnesium alloy structural component further includes an electroplated layer disposed on the surface of the graphene coating facing away from the structural component substrate, and the surface of the electroplated layer facing away from the graphene coating is a multicolored surface.

[0009] This invention also proposes a method for processing magnesium alloy structural parts, comprising the following steps: We provide structural component substrates, graphene powder, binders, silane coupling agents, and deionized water. Graphene slurry is prepared using the graphene powder, the binder, the silane coupling agent, and the deionized water. The structural component substrate is subjected to pretreatment and surface activation treatment in sequence to obtain a surface-activated structural component substrate; A layer of the graphene slurry is coated on the surface of the surface-activated structural substrate, and after drying, a graphene coating is formed.

[0010] In one embodiment, the step of preparing graphene slurry using the graphene powder, the binder, the silane coupling agent, and the deionized water includes: The silane coupling agent and the deionized water are mixed to obtain a first mixture; The graphene powder was added to the first mixture, and after the first stirring and dispersion, a second mixture was obtained. The binder is added to the second mixture, and after a second stirring and dispersion, a graphene slurry is obtained.

[0011] In one embodiment, the initial stirring and dispersion rate is 1000 r / min-5000 r / min, and the stirring time is 1 h-4 h; and / or, The second stirring and dispersion rate is 200 r / min-400 r / min, and the stirring time is 30 min-60 min.

[0012] In one embodiment, the pretreatment includes sandblasting and / or polishing; and / or, The surface activation treatment includes plasma treatment, wherein the plasma treatment time is 5 min-30 min; and / or, The drying process includes: Pre-dry at 40℃-60℃ for 10-20 minutes, then bake at 60℃-250℃ for 20-40 minutes.

[0013] In one embodiment, after the step of coating the surface of the surface-activated magnesium alloy structural component with a layer of the magnesium alloy graphene slurry and drying it to form a graphene coating, the method further includes: A layer of metal material is electroplated onto the surface of the graphene coating to form an electroplated layer; The surface of the electroplated layer is subjected to physical vapor deposition or anodizing treatment to form a multicolored surface.

[0014] The magnesium alloy structural component provided by this invention includes a structural component substrate and a graphene coating disposed on the surface of the structural component substrate. The graphene coating includes graphene, a binder, and a silane coupling agent. Graphene possesses excellent chemical inertness, a dense two-dimensional sheet structure, and extremely low electron / ion permeability, effectively blocking the diffusion of water molecules, oxygen, and corrosive ions into the magnesium alloy substrate, forming a physical barrier. The binder provides the film-forming properties and mechanical strength of the graphene coating, firmly fixing the graphene sheets to the surface of the magnesium alloy substrate. Simultaneously, it fills the pores between the graphene sheets, further enhancing the density and shielding effect of the coating. One end of the silane coupling agent chemically bonds to the hydroxyl groups on the magnesium alloy surface, while the other end is compatible with the functional groups on the binder or graphene surface, significantly improving the interfacial bonding force between the graphene coating and the structural component substrate. Meanwhile, a graphene coating composed of graphene, binder, and silane coupling agent in appropriate mass ratio is applied to the surface of the structural component substrate. This not only enhances the corrosion resistance of magnesium alloy structural components through the physical barrier of the graphene sheet structure and the chemical passivation of the silane coupling agent, but also provides a pretreatment layer with high chemical stability, strong interfacial bonding, and uniform surface for subsequent electroplating. This effectively solves the problems of uneven film layer, incomplete plating, and poor adhesion that exist in the existing direct electroplating of magnesium alloys, and meets the quality requirements of the electroplating process. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0016] Figure 1 This is a cross-sectional structural diagram of an embodiment of the magnesium alloy structural component provided by the present invention.

[0017] Explanation of icon numbers: 100. Magnesium alloy structural components; 1. Structural component substrate; 2. Graphene coating; 3. Electroplating layer; 31. Multicolored surface.

[0018] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0021] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0022] Magnesium alloys, due to their low density, high specific strength, and high specific stiffness, have seen increasing applications in smart wearable products in recent years to meet the dual demands of high strength and lightweight design. However, magnesium alloys have extremely poor corrosion resistance. Direct electroplating without surface treatment easily leads to uneven plating, missed plating, and insufficient adhesion, making it difficult to meet the quality requirements of the electroplating process.

[0023] To address the aforementioned technical problems, this invention proposes a magnesium alloy structural component, aiming to improve the corrosion resistance of the magnesium alloy structural component and meet the quality requirements of the electroplating process.

[0024] Please see Figure 1 In one embodiment of the present invention, the magnesium alloy structural component 100 includes a structural component substrate 1 and a graphene coating 2 disposed on the surface of the structural component substrate 1. The graphene coating 2 includes graphene, a binder and a silane coupling agent; wherein the mass ratio of graphene, binder and silane coupling agent is (2-25):(30-50):(0.2-5).

[0025] The structural component base 1 is made of magnesium alloy, and its specific structure can be the shell of a smart wearable product, which is not limited here. The structural component base 1 can be a magnesium alloy die-cast part or a rolled part.

[0026] Graphene possesses excellent chemical inertness, a dense two-dimensional sheet structure, and extremely low electron / ion permeability, which can effectively block the diffusion of water molecules, oxygen, and corrosive ions into the magnesium alloy matrix, forming a physical barrier. At the same time, the high conductivity of graphene can also improve the uniformity of current distribution in the subsequent electroplating process, which helps to obtain a denser and stronger electroplated layer.

[0027] The binder provides the film-forming properties and mechanical strength of the graphene coating 2, firmly fixing the graphene sheets to the surface of the magnesium alloy substrate and preventing the graphene coating from falling off during subsequent electroplating. At the same time, it fills the pores between the graphene sheets, further enhancing the density and shielding effect of the graphene coating 2.

[0028] One end of the silane coupling agent chemically bonds with the hydroxyl groups on the magnesium alloy surface, while the other end is compatible with the functional groups on the surface of the binder or graphene, significantly improving the interfacial bonding force between the graphene coating 2 and the substrate 1 of the structural component; at the same time, it can also improve the dispersibility of graphene in the binder, avoid agglomeration, and ensure the uniformity of the graphene coating 2.

[0029] This invention employs a graphene coating 2 composed of graphene, binder, and silane coupling agent in appropriate mass ratios, which is applied to the surface of the structural component substrate 1. This coating not only enhances the corrosion resistance of the magnesium alloy structural component through the combined effect of the physical barrier of the graphene sheet structure and the chemical passivation of the silane coupling agent, but also provides a pretreatment layer with high chemical stability, strong interfacial bonding, and uniform surface for subsequent electroplating. This effectively solves the problems of uneven film layer, incomplete plating, and poor adhesion that exist in existing direct electroplating of magnesium alloys, thus meeting the quality requirements of the electroplating process.

[0030] When the magnesium alloy structural component 100 of the present invention is applied to smart wearable products, it can meet the comprehensive requirements of smart wearable products for lightweight, high strength and high-quality appearance.

[0031] In graphene coating 2, the mass ratio of graphene, binder and silane coupling agent is (2-25):(30-50):(0.2-5), for example, the mass ratios are 2:30:0.2, 2:50:0.2, 2:50:5, 2:30:5, 25:30:0.2, 2:50:0.2, 25:50:5, 25:30:5 and the range between any two endpoints.

[0032] Limiting the graphene content within the aforementioned range achieves a good physical barrier effect, improving the corrosion resistance of magnesium alloy structural components. It also facilitates the subsequent formation of a denser, more tightly bonded electroplated layer. If the graphene content is too low, the physical shielding effect is insufficient; if the graphene content is too high, it can lead to agglomeration, coating embrittlement, or increased porosity, thereby affecting corrosion resistance and the quality of subsequent electroplating.

[0033] Limiting the binder content within the aforementioned range ensures that the graphene coating exhibits good film-forming properties, flexibility, and adhesion. If the binder content is too low, the film strength will be insufficient, making it prone to cracking; if the binder content is too high, it will dilute the shielding effect of the graphene. Limiting the content of silane coupling agent within the above-mentioned range can effectively improve the dispersibility of graphene, enhance the chemical bonding between the graphene coating and the substrate of the structural component, and improve interfacial stability. If the content of silane coupling agent is too high, it will lead to self-condensation side reactions, affecting the uniformity of the graphene coating 2.

[0034] This invention, by rationally controlling the mass ratio of each component in the graphene coating 2, enables the graphene coating 2 to possess both high corrosion resistance, strong interfacial bonding force, and electroplating compatibility, effectively solving the problem of poor corrosion resistance of magnesium alloys.

[0035] In an optional embodiment of the present invention, the number of graphene layers is 1-5, for example, 1, 2, 3, 4, or 5 layers.

[0036] Single-layer or few-layer graphene has a relatively dense two-dimensional structure, which can effectively block the penetration of corrosive media and significantly improve corrosion resistance, while also exhibiting good flexibility. If the number of graphene layers is too large, the interlayer van der Waals forces are weak, making it prone to slippage, porosity, or microcracks, affecting the barrier effect and increasing the brittleness of the graphene coating.

[0037] In an optional embodiment of the present invention, the graphene particle size is 5μm-30μm, for example, the particle size is 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, or any range between two endpoints.

[0038] Selecting graphene within the aforementioned particle size range not only results in a large coverage area and more continuous layer overlap, forming a more complete physical barrier with high blocking effect, but also good dispersion performance.

[0039] In an alternative embodiment of the invention, the adhesive comprises styrene-butadiene rubber and / or acrylic acid.

[0040] Styrene-butadiene rubber is used as a binder, resulting in good film flexibility and impact resistance; acrylic acid is used as a binder, which has good compatibility with silane coupling agents and is environmentally friendly.

[0041] In an optional embodiment of the present invention, the thickness of the graphene coating is 1μm-3μm, for example, the thickness of the graphene coating is 1μm, 2μm, 3μm and any range between two endpoints.

[0042] Limiting the thickness of the graphene coating to the above range can effectively improve corrosion resistance and provide a smooth, stable, and highly adhesive interface for subsequent electroplating.

[0043] Refer again Figure 1 In an optional embodiment of the present invention, the magnesium alloy structure 100 further includes an electroplated layer 3, which is disposed on the surface of the graphene coating 2 facing away from the structural substrate 1, and the surface of the electroplated layer 3 facing away from the graphene coating 2 is a multicolored surface 31.

[0044] The electroplated layer 3 provides a foundation for conductive continuity and metallic texture. Simultaneously, as the platform supporting the multi-colored surface 31, the smoothness, density, and purity of the electroplated layer 3 directly affect the color effect. The metallic material of the electroplated layer 3 includes, but is not limited to, at least one of nickel, zinc, copper, aluminum, and cadmium.

[0045] Optionally, the thickness of the electroplated layer 3 is 2μm-10μm, such as 2μm, 5μm, 8μm, or any range between two endpoints.

[0046] The multicolored surface 31 can be constructed with optical interference color rendering, surface micro-nano structures or selective oxide films on the surface of the electroplated layer 3 facing away from the graphene coating 2 by physical or electrochemical means, thereby presenting rich colors.

[0047] The present invention also proposes a processing method for magnesium alloy structural component 100, which is used to process magnesium alloy structural component 100.

[0048] In one embodiment of the present invention, the processing method includes the following steps: (1) Provide structural component matrix, graphene powder, binder, silane coupling agent and deionized water; (2) Graphene slurry was prepared using graphene powder, binder, silane coupling agent and deionized water; (3) The structural component substrate is pretreated and surface activated in sequence to obtain a surface activated structural component substrate; (4) A layer of graphene slurry is coated on the surface of the surface-activated structural component substrate, and a graphene coating is formed after drying.

[0049] The structural component substrate is made of magnesium alloy, and the specific structure can be the shell of a smart wearable product. The structural component substrate can be a magnesium alloy die-casting or rolled part. The binder uses at least one of styrene-butadiene rubber latex and acrylic latex. The silane coupling agent uses at least one of amino silane coupling agents, epoxy silane coupling agents, and methacryloyloxy silane coupling agents. Optionally, the silane coupling agent is at least one of γ-aminopropyltriethoxysilane (KH-550), γ-glycidoxypropyltrimethoxysilane (KH-560), and γ-methacryloyloxypropyltrimethoxysilane (KH-570).

[0050] When preparing graphene slurry, the raw materials include 2-25 parts graphene powder, 30-50 parts binder, 0.2-5 parts silane coupling agent, and 20-80 parts deionized water by mass.

[0051] The physical parameters of graphene and the thickness of the graphene coating can be referred to in the above embodiments, and will not be repeated here.

[0052] The processing method for magnesium alloy structural parts of this invention is simple to operate and relatively low in cost. By pre-treating and surface-activating the substrate of the structural part and coating it with a layer of graphene slurry, a graphene coating is formed after drying. The graphene coating not only improves the corrosion resistance of the magnesium alloy structural parts, but also provides a pre-treatment layer with high chemical stability, strong interfacial bonding, and uniform surface for subsequent electroplating. This effectively solves the problems of uneven film layer, incomplete plating, and poor adhesion that exist in the existing direct electroplating of magnesium alloys, and meets the quality requirements of the electroplating process.

[0053] It should be noted that graphene powder, due to its strong van der Waals forces and tendency to agglomerate, requires high-speed shearing to achieve uniform dispersion. Meanwhile, the binder, styrene-butadiene rubber and / or acrylic emulsion, is an aqueous polymer micelle system, sensitive to high shear. The excessive shear force from high-speed stirring can easily lead to demulsification, making the system unstable; therefore, only slow stirring is possible. Based on this, to balance sufficient graphene dispersion with emulsion system stability, this invention involves the distributed mixing of the raw materials during the preparation of the graphene slurry.

[0054] In some embodiments of the present invention, step (2) specifically includes the following steps: (21) Mix the silane coupling agent and deionized water to obtain the first mixture; (22) Add graphene powder to the first mixture, and after the first stirring and dispersion, obtain the second mixture; (23) Add binder to the second mixture, and after stirring and dispersing for the second time, obtain graphene slurry.

[0055] The initial stirring and dispersion rate is 1000 r / min to 5000 r / min, for example, the rate is 1000 r / min, 2000 r / min, 3000 r / min, 4000 r / min, 5000 r / min, or any interval between two endpoints; the stirring time is 1 h to 4 h, for example, the stirring time is 1 h, 2 h, 3 h, 4 h, or any interval between two endpoints.

[0056] Graphene is treated under the above-mentioned high-speed shearing to obtain a stable, non-agglomerated, and uniformly dispersed graphene pre-dispersion. At the same time, a silane coupling agent is used to modify the surface of the graphene hydrophobically, thereby improving its compatibility with subsequent organic emulsions.

[0057] Optionally, the second stirring and dispersion rate is 200 r / min to 400 r / min, for example, a range of 200 r / min, 300 r / min, 400 r / min, or any two endpoints; the stirring time is 30 min to 60 min, for example, a range of 30 min, 40 min, 50 min, 60 min, or any two endpoints.

[0058] By using the above-mentioned low-speed stirring to mix the graphene pre-dispersion liquid with the binder, a graphene slurry with uniform dispersion, complete emulsion structure, and stable system can be obtained.

[0059] It should be noted that in some optional embodiments, defoamer and / or dispersant are also added to the second mixture to obtain a uniformly dispersed, stable, and bubble-free graphene slurry. The amount of defoamer and dispersant is not limited here and can be determined according to actual operation.

[0060] In some embodiments of the present invention, pretreatment includes sandblasting and / or polishing.

[0061] The purpose of sandblasting is to clean the surface of the structural component substrate, remove mold release agents, oxide scale, oil stains, and loose surface layers formed during casting / rolling; increase surface roughness to improve the mechanical bonding adhesion of subsequent graphene coatings; and activate the surface to facilitate the formation of Si-O-Mg bonds between the subsequent silane coupling agent and the metal surface.

[0062] Polishing serves to obtain a high-gloss surface, which is beneficial to improve the appearance quality; reduce surface defects and eliminate micro-unevennesses such as die-casting porosity, flow marks, and rolling scratches; reduce specific surface area, reduce the amount of subsequent graphene coating, and improve film thickness uniformity.

[0063] In some embodiments of the present invention, the surface activation treatment includes plasma treatment, wherein the plasma treatment time is 5 min to 30 min, for example, the time is 5 min, 10 min, 20 min, 30 min, or an interval between any two endpoints.

[0064] The purpose of plasma treatment is to further clean and chemically modify the surface, so that polar groups such as -OH and -COOH are generated on the surface in oxygen or air plasma, which is beneficial to enhance the bonding force between the graphene coating and the substrate of the structural component; and it can also increase the surface energy, which is beneficial to improve the wetting and spreading properties of the graphene coating.

[0065] By controlling the processing time within the aforementioned range, the surface of the structural component substrate can be effectively activated, significantly improving the surface cleanliness and reactivity, and providing a deposition interface with high adhesion and high uniformity for the graphene coating. If the processing time is less than 5 minutes, insufficient polar groups will be generated, affecting the adhesion between the graphene coating and the structural component substrate; if the processing time is greater than 30 minutes, the surface hydroxyl groups will be saturated, resulting in excessive etching and damage to the surface of the structural component substrate.

[0066] In some embodiments of the present invention, step (4) of drying includes: Pre-dry at 40℃-60℃ (e.g., 40℃, 50℃, 60℃ and any range between two endpoints) for 10min-20min (e.g., 10min, 15min, 20min and any range between two endpoints), then bake at 60℃-250℃ (e.g., 60℃, 100℃, 150℃, 200℃, 250℃ and any range between two endpoints) for 20min-40min (e.g., 20min, 30min, 40min and any range between two endpoints).

[0067] In this invention, the graphene coating is first pre-dried at a low temperature and then dried at a high temperature. The low-temperature pre-drying is to allow the solvent in the graphene coating to evaporate slowly, avoiding rapid drying of the surface of the graphene coating, which would prevent the solvent inside from being discharged in time and causing defects such as cracks and bubbles. The high-temperature drying further dries and solidifies the organic components in the graphene coating, improves the density of the graphene coating, and enhances the bonding force between the graphene coating and the substrate of the structural component.

[0068] In some embodiments of the present invention, after step (4), the following steps are also included: (5) Electroplating a layer of metal material onto the surface of the graphene coating to form an electroplated layer; (6) Physical vapor deposition or anodizing treatment is performed on the surface of the electroplated layer to form a colorful surface.

[0069] Specifically, the metal materials include, but are not limited to, at least one of nickel, zinc, copper, cadmium, and aluminum. The electroplating operation parameters and the thickness of the electroplated layer are not limited here and are determined according to the actual operation.

[0070] When the metal material of the electroplated layer is at least one of nickel, zinc, copper, and cadmium, a multicolored surface can be obtained by treating the surface of the electroplated layer through physical vapor deposition; when the metal material of the electroplated layer is aluminum, a multicolored surface can be obtained by anodizing the surface of the electroplated layer. The specific operating parameters for physical vapor deposition and anodizing are not limited here and will be determined based on actual operation.

[0071] Example The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0072] Example 1 (1) Preparation of graphene slurry: 1g of silane coupling agent KH-550 was mixed with 40g of deionized water and hydrolyzed for 30min. Then, 15g of graphene powder was added and dispersed evenly. Finally, 35g of styrene-butadiene rubber emulsion was slowly added and stirred evenly to prepare water-based graphene slurry.

[0073] (2) Processing of magnesium alloy structural parts: The rolled structural parts substrate is subjected to sandblasting, polishing and plasma activation treatment for 10 min in sequence to obtain surface activated structural parts substrate; then a 1.5 μm thick graphene slurry is sprayed on the surface of the surface activated structural parts substrate, pre-drying at 50℃ for 15 min and drying at 120℃ for 30 min to form a graphene coating.

[0074] The adhesion of the graphene coating was tested using the cross-cut adhesion test according to standard ISO2409 / ASTM D3359. The adhesion grade of the graphene coating was measured to be 5B, indicating high adhesion and strong bonding between the graphene coating and the substrate of the structural component. Further analysis using the four-probe method revealed that the resistivity of the graphene coating was 5.4 × 10⁻⁶. -6 Ω.m. Furthermore, subsequent electroplating operations can achieve a uniform electroplated layer, meeting the quality requirements of the electroplating process.

[0075] Example 2 (1) Preparation of graphene slurry: 2g of silane coupling agent KH-550 was mixed with 60g of deionized water and hydrolyzed for 40min. Then, 20g of graphene powder was added and dispersed evenly. Finally, 45g of styrene-butadiene rubber emulsion was slowly added and stirred evenly to prepare water-based graphene slurry.

[0076] (2) Processing of magnesium alloy structural parts: The rolled structural parts substrate is subjected to sandblasting, polishing and plasma activation treatment for 20 min in sequence to obtain surface activated structural parts substrate; then a 2 μm thick graphene slurry is sprayed on the surface of the surface activated structural parts substrate, pre-drying at 60℃ for 12 min and drying at 250℃ for 35 min to form a graphene coating.

[0077] The adhesion of the graphene coating was tested using the cross-cut adhesion test according to standard ISO2409 / ASTM D3359. The adhesion grade of the graphene coating was measured to be 5B, indicating high adhesion and strong bonding between the graphene coating and the substrate of the structural component. Further analysis using the four-probe method revealed that the resistivity of the graphene coating was 5.6 × 10⁻⁶. -6 Ω.m. Furthermore, subsequent electroplating operations can achieve a uniform electroplated layer, meeting the quality requirements of the electroplating process.

[0078] Example 3 (1) Preparation of graphene slurry: 4g of silane coupling agent KH-550 was mixed with 80g of deionized water and hydrolyzed for 50min. Then, 25g of graphene powder was added and dispersed evenly. Finally, 50g of styrene-butadiene rubber emulsion was slowly added and stirred evenly to prepare water-based graphene slurry.

[0079] (2) Processing of magnesium alloy structural parts: The rolled structural parts substrate is subjected to sandblasting, polishing and plasma activation treatment for 30 min in sequence to obtain surface activated structural parts substrate; then a 2.5 μm thick graphene slurry is sprayed on the surface of the surface activated structural parts substrate, pre-drying at 50℃ for 20 min and drying at 200℃ for 40 min to form a graphene coating.

[0080] The adhesion of the graphene coating was tested using the cross-cut adhesion test according to standard ISO2409 / ASTM D3359. The adhesion grade of the graphene coating was measured to be 5B, indicating high adhesion and strong bonding between the graphene coating and the substrate of the structural component. Further analysis using the four-probe method revealed that the resistivity of the graphene coating was 5.8 × 10⁻⁶. -6 Ω.m. Furthermore, subsequent electroplating operations can achieve a uniform electroplated layer, meeting the quality requirements of the electroplating process.

[0081] Example 4 (1) Preparation of graphene slurry: 0.5g of silane coupling agent KH-550 was mixed with 30g of deionized water and hydrolyzed for 25min. Then, 5g of graphene powder was added and dispersed evenly. Finally, 50g of styrene-butadiene rubber emulsion was slowly added and stirred evenly to prepare water-based graphene slurry.

[0082] (2) Processing of magnesium alloy structural parts: The rolled structural parts substrate is subjected to sandblasting, polishing and plasma activation treatment for 5 min in sequence to obtain surface activated structural parts substrate; then a 1 μm thick graphene slurry is sprayed on the surface of the surface activated structural parts substrate, pre-drying at 40℃ for 15 min and drying at 80℃ for 30 min to form a graphene coating.

[0083] The adhesion of the graphene coating was tested using the cross-cut adhesion test according to standard ISO2409 / ASTM D3359. The adhesion grade of the graphene coating was measured to be 5B, indicating high adhesion and strong bonding between the graphene coating and the substrate of the structural component. Further analysis using the four-probe method revealed that the resistivity of the graphene coating was 5.2 × 10⁻⁶. -6 Ω.m. Furthermore, subsequent electroplating operations can achieve a uniform electroplated layer, meeting the quality requirements of the electroplating process.

[0084] Comparative Example 1 (1) Preparation of graphene slurry: 1g of silane coupling agent KH-550 was mixed with 40g of deionized water and hydrolyzed for 30min. Then, 1g of graphene powder was added and dispersed evenly. Finally, 35g of styrene-butadiene rubber emulsion was slowly added and stirred evenly to prepare water-based graphene slurry.

[0085] (2) Processing of magnesium alloy structural parts: The rolled structural parts substrate is subjected to sandblasting, polishing and plasma activation treatment for 10 min in sequence to obtain surface activated structural parts substrate; then a 1.5 μm thick graphene slurry is sprayed on the surface of the surface activated structural parts substrate, pre-drying at 50℃ for 15 min and drying at 120℃ for 30 min to form a graphene coating.

[0086] The adhesion of the graphene coating was tested using the cross-cut adhesion test according to standard ISO2409 / ASTM D3359. The adhesion grade of the graphene coating was measured to be 5B, indicating high adhesion and strong bonding between the graphene coating and the substrate of the structural component. Further analysis using the four-probe method revealed that the resistivity of the graphene coating was 3.9 × 10⁻⁶. -1 Ω.m. Meanwhile, during subsequent electroplating operations, the graphene coating has a high resistivity, resulting in uneven current distribution and poor conductivity, leading to incomplete plating and failing to meet the quality requirements of the electroplating process.

[0087] Comparative Example 2 (1) Preparation of graphene slurry: 1g of silane coupling agent KH-550 was mixed with 40g of deionized water and hydrolyzed for 30min. Then, 40g of graphene powder was added and dispersed evenly. Finally, 35g of styrene-butadiene rubber emulsion was slowly added and stirred evenly to prepare water-based graphene slurry.

[0088] (2) Processing of magnesium alloy structural parts: The rolled structural parts substrate is subjected to sandblasting, polishing and plasma activation treatment for 10 min in sequence to obtain surface activated structural parts substrate; then a 1.5 μm thick graphene slurry is sprayed on the surface of the surface activated structural parts substrate, pre-drying at 50℃ for 15 min and drying at 120℃ for 30 min to form a graphene coating.

[0089] The adhesion of the graphene coating was tested using the cross-cut adhesion test according to standard ISO2409 / ASTM D3359. The adhesion grade of the graphene coating was measured to be 2B, indicating poor adhesion, meaning that the graphene coating has a weak bond with the substrate. Further testing using the four-probe method revealed that the resistivity of the graphene coating was 2.5 × 10⁻⁶. -6 Ω.m. Meanwhile, during subsequent electroplating operations, the excessive amount of graphene resulted in uneven agglomeration and dispersion, leading to poor coating adhesion and peeling off of the graphene coating. The substrate of the structural component was also corroded and failed during the electroplating process, failing to meet the quality requirements of the electroplating process.

[0090] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A magnesium alloy structural component, characterized in that, The magnesium alloy structural component includes a structural component substrate and a graphene coating disposed on the surface of the structural component substrate. The graphene coating includes graphene, a binder, and a silane coupling agent; wherein, The mass ratio of the graphene, the binder, and the silane coupling agent is (2-25):(30-50):(0.2-5).

2. The magnesium alloy structural component as described in claim 1, characterized in that, The graphene has 1-5 layers; and / or, The graphene has a particle size of 5μm-30μm.

3. The magnesium alloy structural component as described in claim 1, characterized in that, The adhesive includes styrene-butadiene rubber and / or acrylic acid.

4. The magnesium alloy structural component as described in claim 1, characterized in that, The thickness of the graphene coating is 1μm-3μm.

5. The magnesium alloy structural component as described in any one of claims 1 to 4, characterized in that, The magnesium alloy structural component also includes an electroplated layer, which is disposed on the surface of the graphene coating facing away from the structural component substrate. The surface of the electroplated layer facing away from the graphene coating is a multicolored surface.

6. A method for processing magnesium alloy structural parts, characterized in that, Includes the following steps: We provide structural component substrates, graphene powder, binders, silane coupling agents, and deionized water. Graphene slurry is prepared using the graphene powder, the binder, the silane coupling agent, and the deionized water. The structural component substrate is subjected to pretreatment and surface activation treatment in sequence to obtain a surface-activated structural component substrate; A layer of the graphene slurry is coated on the surface of the surface-activated structural substrate, and after drying, a graphene coating is formed.

7. The processing method for magnesium alloy structural parts as described in claim 6, characterized in that, The steps for preparing graphene slurry using the graphene powder, the binder, the silane coupling agent, and the deionized water include: The silane coupling agent and the deionized water are mixed to obtain a first mixture; The graphene powder was added to the first mixture, and after the first stirring and dispersion, a second mixture was obtained. The binder is added to the second mixture, and after a second stirring and dispersion, a graphene slurry is obtained.

8. The processing method for magnesium alloy structural parts as described in claim 7, characterized in that, The first stirring and dispersion rate is 1000 r / min-5000 r / min, and the stirring time is 1 h-4 h; and / or, The second stirring and dispersion rate is 200 r / min-400 r / min, and the stirring time is 30 min-60 min.

9. The processing method for magnesium alloy structural parts as described in claim 6, characterized in that, The pretreatment includes sandblasting and / or polishing; and / or, The surface activation treatment includes plasma treatment, wherein the plasma treatment time is 5 min-30 min; and / or, The drying process includes: Pre-dry at 40℃-60℃ for 10-20 minutes, then bake at 60℃-250℃ for 20-40 minutes.

10. A method for processing magnesium alloy structural parts as described in any one of claims 6 to 9, characterized in that, After the step of coating the surface of the surface-activated magnesium alloy structural component with a layer of the magnesium alloy graphene slurry and drying it to form a graphene coating, the method further includes: A layer of metal material is electroplated onto the surface of the graphene coating to form an electroplated layer; The surface of the electroplated layer is subjected to physical vapor deposition or anodizing treatment to form a multicolored surface.

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