A plastic-coated metal member

Abstract

The utility model discloses a kind of plastic-coated metal components, including metal base and plastic layer, by forming micropore on the surface of metal base, and setting lateral expansion part bifurcated horizontally below micropore, plastic layer can be fully infiltrated into micropore and lateral expansion part in injection molding process, form multilayer, multiple point mechanical locking structure, so the overall reliability of the plastic-coated metal component is strong.Secondly, the ratio of the opening diameter of micropore on the surface of metal base and the maximum diameter of hole inner main cavity section is 0.35~0.8, so that micropore presents "reverse buckle" geometric shape, plastic is firmly clamped in hole cavity after solidification, realize longitudinal and lateral composite locking, so as to significantly enhance the tensile resistance, peel resistance and impact resistance between metal base and plastic layer.Meanwhile, the size, hole depth and hole proportion of micropore are limited in suitable range, so that plastic can be smoothly filled in each micropore in injection molding process without affecting the structural strength of metal base, realize the reasonable balance between high bonding force and strength.

Description

Technical Field

[0001] This utility model relates to the field of metal-plastic composite technology, specifically a plastic-coated metal component. Background Technology

[0002] Plastic-coated metal components are widely used in the automotive, electronics, electrical appliances, medical devices, and consumer goods industries. Their typical structure involves coating a metal substrate with a layer of plastic to combine the strength of metal with the insulation, cushioning, and aesthetic functions of plastic. Current plastic coating methods primarily rely on adhesive bonding or roughening the metal surface through sandblasting or mechanical etching to create a certain roughness, followed by injection molding to bond the plastic layer to the metal substrate. However, these surface roughness-dependent bonding methods are mostly physical adhesions with limited bond strength. When the component is subjected to tensile forces, bending forces, or thermal expansion and contraction stresses during use, the plastic layer is prone to cracking, peeling, or detachment, affecting the overall reliability of the component.

[0003] To improve bonding strength, some existing technologies attempt to create through-holes or grooves on the metal surface, allowing the plastic to penetrate and cure during molding. However, these structures are often large in size, easily weakening the strength of the metal substrate, and are difficult to achieve high-density distribution at the microscale, resulting in unsatisfactory bonding effects. Furthermore, existing technologies also generate micropores on the metal surface. These micropore structures are mostly simple cylindrical or conical holes, lacking effective interlocking or anchoring designs, leaving the plastic layer at risk of loosening and peeling under long-term stress. Therefore, it is necessary to provide a plastic-coated metal component that can achieve a stable mechanical interlock while balancing the strength of the metal substrate and the reliability of the plastic layer bonding. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model provides a plastic-coated metal component, which effectively improves the problem of low bonding strength between plastic and metal in some traditional plastic-coated metal components. A plastic-coated metal component includes a metal substrate and a plastic layer. The metal substrate has a plurality of micropores extending inward from its surface. The plastic layer covers the surface of the metal substrate and penetrates into the micropores to form a mechanical interlocking connection with the metal substrate. The micropores extend inward from the surface of the metal substrate, and the ratio d0 / dmax of the opening diameter d0 of the micropore to the maximum diameter dmax of the main cavity section within the micropore is 0.35 to 0.8. Each micropore has at least one laterally branched lateral extension below its main cavity section, and the minimum diameter of the lateral extension is 1 / 3 to 1 times the opening diameter of the micropore. The opening diameter of the micropore is 20 to 300 μm, the pore depth is 20 to 200 μm, and the proportion of micropores on the surface of the metal substrate is 30% to 90%.

[0005] Preferably, the metal matrix is ​​a titanium alloy metal workpiece, which includes titanium and its alloy metal workpieces, titanium-copper composite metal workpieces with copper shielding, titanium-steel composite metal workpieces with steel shielding, and titanium-aluminum composite metal workpieces after anodizing.

[0006] Preferably, the plastic layer is a resin plastic layer or a thermoplastic elastomer plastic layer.

[0007] Preferably, the opening diameter of the micropore is 20-150 μm, the pore depth is 5-15 μm, and the proportion of the micropores on the surface of the metal workpiece is 30-50%.

[0008] Preferably, the number of lateral extensions of the micropores is 2 to 16.

[0009] Preferably, the lateral extensions are evenly distributed circumferentially around the axis of the main cavity section inside the hole.

[0010] Preferably, the lateral extension extends radially.

[0011] Preferably, the end of the lateral extension away from the main cavity section inside the hole is hook-shaped or barbed.

[0012] Preferably, the angle between the lateral extension and the axis of the main cavity section inside the hole is 30° to 90°.

[0013] Preferably, the inner wall of the lateral extension is provided with a plurality of coral-shaped slits extending outward.

[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a plastic-coated metal component comprising a metal substrate and a plastic layer. By forming micropores on the surface of the metal substrate and providing laterally branched extensions below the micropores, the plastic layer can fully penetrate the micropores and lateral extensions during injection molding, forming a multi-layered, multi-point mechanical locking structure. Therefore, the overall reliability of this plastic-coated metal component is high. Furthermore, the ratio of the opening diameter of the micropores on the metal substrate surface to the maximum diameter of the main cavity within the pore is 0.35~0.8, giving the micropores a "reverse interlocking" geometric shape. After curing, the plastic is firmly embedded inside the cavity, achieving a composite locking mechanism both longitudinally and laterally. This significantly enhances the pull-out resistance, peel resistance, and impact resistance between the metal substrate and the plastic layer. Meanwhile, the size, depth, and proportion of micropores are limited to a suitable range, allowing the plastic to smoothly fill each micropore during injection molding without affecting the structural strength of the metal matrix. This achieves a reasonable balance between high bonding strength and metal matrix strength, effectively increasing the effective contact area between the metal matrix and the plastic layer, optimizing stress distribution, reducing local stress concentration, and significantly improving the reliability, durability, and overall structural stability of the plastic-coated metal component during long-term use. Therefore, this plastic-coated metal component can maintain excellent bonding performance under complex mechanical loads and thermal stress conditions. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the cross-sectional structure of the plastic-coated metal component of this utility model; in: 10-Micropores, 20-Metal substrate, 30-Plastic layer, 11-Opening, 12-Main cavity segment, 13-Lateral extension, 14-Hook-shaped, 15-Gap. Detailed Implementation

[0016] The embodiments described below are merely some embodiments of this utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

[0017] See Figure 1This embodiment provides a plastic-coated metal component, comprising a metal substrate 20 and a plastic layer 30. The metal substrate 20 has a plurality of micropores 10 extending inward from its surface. The plastic layer 30 covers the surface of the metal substrate 20 and penetrates into the micropores 10 to form a mechanical interlocking connection with the metal substrate 20. The micropores 10 extend inward from the surface of the metal substrate 20, and the ratio d0 / dmax of the diameter d0 of the opening 11 of the micropore 10 to the maximum diameter dmax of the main cavity section 12 within the micropore 10 is... The diameter is 0.35~0.8. The micropore 10 has at least one laterally branched lateral extension 13 below its main cavity section 12. The minimum diameter of the lateral extension 13 is 1 / 3 to 1 times the diameter of the opening 11 of the micropore 10. The diameter of the opening 11 of the micropore 10 is 20~300μm, the depth is 20~200μm, and the proportion of the micropore 10 on the surface of the metal substrate 20 is 30%~90%.

[0018] Preferably, the metal substrate is a titanium alloy metal workpiece, which includes titanium and its alloy metal workpieces, titanium-copper composite metal workpieces with copper shielding, titanium-steel composite metal workpieces with steel shielding, and anodized titanium-aluminum composite metal workpieces. The surface of the titanium alloy metal workpiece is chemically etched to form a microporous structure 10 that facilitates plastic penetration and mechanical interlocking, thereby further enhancing the adhesion and interfacial bonding strength between the plastic layer 30 and the metal substrate 20.

[0019] Preferably, the plastic layer 30 is a resin plastic layer 30 or a thermoplastic elastomer plastic layer 30. During injection molding, the plastic layer 30 can fully penetrate the micropores 10 and their lateral extensions 13, and form a stable mechanical interlocking structure after cooling and curing. The plastic layer 30 has good flexibility and impact resistance, effectively absorbing external loads and vibrations, while providing insulation, corrosion resistance, and aesthetic effects, thereby significantly improving the bonding strength between the metal substrate 20 and the plastic layer 30 and the overall durability of the coated component.

[0020] Preferably, the opening diameter 11 of the micropore 10 is 20-150 μm, the pore depth is 5-15 μm, and the proportion of micropores 10 on the surface of the metal workpiece is 30-50%. By limiting the size and distribution of the micropores 10 within the above-mentioned preferred range, it can be ensured that the plastic melt smoothly penetrates and fully fills the metal during injection molding, while forming a stable mechanical locking structure. Within this range, the micropores 10 can provide sufficient anchor volume without significantly weakening the matrix strength of the metal workpiece due to excessively large pore diameter or high pore density, thus achieving a reasonable balance between strength and bonding force. Further, with an opening diameter of 150 μm, a pore depth of 15 μm, and a pore proportion of 40% as the optimal implementation method, experiments show that it can form an efficient "reverse interlocking" effect at the junction of the metal matrix 20 and the plastic layer 30, significantly improving the resistance to pull-out, peeling, and impact, while ensuring the structural stability of the metal workpiece body.

[0021] More preferably, the ratio d0 / dmax of the opening 11 diameter d0 of the micropore 10 to the maximum diameter dmax of the main cavity section 12 inside the micropore 10 is 0.6~0.8. By controlling d0 / dmax within this range, a relatively small entrance can be formed on the surface of the micropore 10, while a larger cavity volume can be formed inside the hole. This allows the molten plastic to have a locking and expanding effect after entering during the injection molding process. This structure not only increases the interfacial contact area between the metal substrate 20 and the plastic layer 30, but also ensures that the plastic is firmly embedded inside the cavity after cooling and shrinking, effectively preventing it from falling off. At the same time, due to the size difference between the opening 11 and the main cavity section 12, the plastic is not easily pulled out as a whole when subjected to external force, thereby significantly improving the pull-out resistance and peel resistance. Furthermore, the optimal embodiment is that the ratio of the diameter d0 of the opening 11 of the micropore 10 to the maximum diameter dmax of the main cavity section 12 inside the micropore 10 is d0 / dmax of 0.8. Experiments show that when d0 / dmax is 0.8, the plastic melt can smoothly enter the cavity during injection molding. After entering the main cavity section 12 through the opening 11, the plastic melt can quickly diffuse and flow into the lateral expansion part 13, forming a locking and expanding effect inside the hole. After the plastic cools and solidifies, it is firmly embedded in the main cavity section 12, which is not only restricted in the longitudinal direction, but also subjected to multiple points of force in the transverse direction, significantly enhancing the pull-out resistance and peel resistance.

[0022] More preferably, the minimum diameter of the lateral extension 13 is 0.7 times the diameter of the opening 11 of the micropore 10. This size range ensures that the molten plastic is smoothly injected into the lateral extension 13 while forming a stable lateral mechanical locking structure. By setting the minimum diameter of the lateral extension 13 to 0.7 times the opening 11 of the micropore 10, the plastic can be firmly embedded in the lateral extension 13 after cooling and solidification, achieving a composite locking effect in both the longitudinal and lateral directions. This significantly improves the pull-out resistance, peel resistance, and impact resistance between the metal substrate 20 and the plastic layer 30. At the same time, this size is not too large, which would weaken the structural strength of the metal substrate 20 around the micropore 10, nor is it too small, which would lead to incomplete injection filling, resulting in voids or insufficient plastic volume inside the lateral extension 13. This ensures a reasonable balance between high bonding strength and the strength of the metal substrate 20 while ensuring smooth injection molding. Experimental results show that when the minimum diameter of the lateral extension 13 is 0.7 times the diameter of the opening 11 of the micropore 10, the best plastic filling effect and the optimal interface bonding strength can be obtained during injection molding.

[0023] It should also be noted that the end of the lateral extension 13 away from the main cavity section 12 inside the hole is designed as a hook 14 or a barb, forming a shape similar to an "anchor" or "octopus claw". This structure can generate a two-way mechanical interlocking force in both the longitudinal and transverse directions after the plastic cools and solidifies. Furthermore, the lateral extension 13 is distributed in a stepped or layered manner along the depth direction of the micropore 10. That is to say, the lateral extension 13 is not completely on the same horizontal plane, which makes the plastic form multi-layered and multi-point support in the hole, achieving a composite locking effect. It not only restricts the plastic from coming out longitudinally, but also forms a stable anchoring point in the transverse direction of the cavity, thereby significantly improving the resistance to pull-out, peeling and impact resistance.

[0024] Preferably, the number of lateral extensions 13 in the micropore 10 is 2 to 16. More preferably, it is 3 to 8. By setting a reasonable number of lateral extensions 13, multiple independent lateral anchoring points can be formed inside each micropore 10, thereby providing more filling area and support structure for the plastic melt during injection molding. The lateral extensions 13 are evenly distributed circumferentially along the axis of the main cavity section 12 inside the hole and extend radially, so that the plastic melt can flow evenly into each lateral extension 13 during injection molding, ensuring that the melt inside the hole is fully filled without voids or defects. At the same time, the evenly distributed lateral extensions 13 can achieve balanced distribution of interface forces. When external forces act on the metal-plastic interface, local stress concentration can be avoided, thereby reducing the risk of interface failure and improving structural durability.

[0025] Preferably, the angle between the lateral extension 13 and the axis of the main cavity section 12 within the hole is 30° to 90°. This effectively adjusts the flow direction and locking effect of the plastic during injection molding. When the angle is small (close to 30°), the lateral extension 13 is closer to the axis of the main cavity section 12, allowing the plastic to flow smoothly along the main cavity section 12 during injection molding, while simultaneously creating a longitudinal restraint effect, enhancing the longitudinal locking force of the plastic within the hole. When the angle is large (close to 90°), the lateral extension 13 is almost perpendicular to the axis of the main cavity section 12, allowing the plastic to form obvious lateral anchoring points after curing, achieving a multi-point lateral restraint effect, thereby significantly improving peel resistance and pull-out resistance.

[0026] Preferably, the inner wall of the lateral extension 13 is provided with a plurality of coral-shaped slits 15 extending outward. The coral-shaped slits 15 serve as a third-level reinforcement structure outside the main cavity section 12 of the micropore 10 and the lateral extension 13. During injection molding, the molten plastic material can penetrate into the coral-shaped slits 15 through the lateral extension 13, filling the slits 15 and forming a multi-point locking structure in both the longitudinal and transverse directions during the cooling and solidification process. The coral-shaped slits 15 not only restrict the plastic in the main cavity section 12 and the lateral extension 13, but also form additional anchoring points inside the coral-shaped slits 15, thereby significantly improving the resistance to pull-out, peeling, and impact. In addition, the presence of the coral-shaped slits 15 further increases the contact area at the interface between the metal substrate 20 and the plastic layer 30, achieving uniform stress distribution and reducing the impact of local stress concentration on the metal substrate 20. While ensuring smooth injection molding, the coral-shaped gap 15 can provide a multi-layered, multi-point composite locking effect, taking into account the bonding strength, durability and overall structural stability of the metal component, and significantly improving the long-term reliability and service life of the plastic-coated metal component.

[0027] Therefore, by reasonably controlling the number, diameter, and distribution of the lateral extensions 13, this embodiment can maximize the locking effect while ensuring smooth melt filling during injection molding, and at the same time avoid excessive weakening of the strength of the metal workpiece matrix. The uniformly arranged lateral extensions 13 not only increase the contact area of ​​the metal-plastic interface, but also uniformly distribute stress on the interface, thereby further improving the long-term durability and reliability of the joint. Through this multi-point, multi-layer, and longitudinally and laterally combined locking structure design, the metal workpiece and plastic workpiece interlocking structure of this utility model can achieve high bonding force, high durability, and good impact resistance, while taking into account the overall stability and structural strength of the metal matrix 20.

[0028] Preferably, the micropores 10 described in this application comprise multiple micropores 10 of different depths. It should be noted that the deeper micropores 10 provide a larger longitudinal locking volume, enhancing the main locking force, while the shallower micropores 10 form surface anchoring points, improving the tightness of the interface adhesion. The complementary arrangement of micropores 10 of different depths ensures a uniform distribution of force at the interface, creating a multi-point locking effect both longitudinally and laterally, similar to a deep base combined with a surface snap-fit ​​structure, significantly improving pull-out resistance, peel resistance, and impact resistance. Simultaneously, because the micropores 10 employ two different depths, the strength of the metal workpiece substrate is not weakened, achieving an optimal balance between bonding force and structural strength, thereby greatly improving the reliability and long-term durability of the joint.

[0029] Preferably, the cross-sectional profile of the opening 11 of the micropore 10 is approximately circular, elliptical, or polygonal.

[0030] The micropores 10 formed by the inward extension of the surface of the metal substrate 20 can be formed through the following steps: S1: Pre-treat the metal substrate 20 to form an etched part; S2: The etched part is used as the anode and the graphite plate is used as the cathode. The part is placed in a microporous etching solution for electrolytic etching to form a metal substrate microporous component with an "octopus-shaped" or "anchor-shaped" microporous structure on the surface. The micropore etching solution comprises, by weight, 10-15 parts organic acid, 5-10 parts pH stabilizer, 10-20 parts dispersant, 9-40 parts etchant, 3-5 parts anisotropic modifier, and 50-80 parts solvent. During the energization process, the anisotropic modifier is adsorbed on the inner surface of the micropores, improving the lateral and longitudinal etching rates. As the pore depth increases, the lateral etching rate continuously increases, causing the micropores to exhibit an "octopus-like" or "anchor-like" structure.

[0031] Step S2 includes the following steps: S2.1: The etched part is used as the anode and the graphite plate is used as the cathode. The part is placed in a microporous etching solution with an etchant and anisotropic modifier mass ratio of at least 8:1 for electrolytic etching to form a microporous component of the initial metal substrate. In this step, when the etchant and anisotropic modifier mass ratio is greater than 8:1, the lateral etching rate of the etching solution on the surface of the metal substrate is greater than the longitudinal etching rate. S2.2: The original metal substrate microporous component is used as the anode and the graphite plate is used as the cathode. Then, it is placed in a microporous etching solution with an etchant and anisotropic modifier mass ratio of up to 3:1 for electrolytic etching. In this step, when the etchant and anisotropic modifier mass ratio is less than 3:1, the etching solution, based on the micropores in the previous step, firstly has a longitudinal etching rate greater than a transverse etching rate. After a period of time, the transverse etching rate will be greater than the longitudinal etching rate, and finally a metal substrate microporous component with an "octopus-shaped" or "anchor-shaped" microporous structure on the surface is formed.

[0032] To achieve a more ideal microporous structure, the electrolytic etching method in steps S2.1 and S2.2 is to first perform high-current constant current electrolysis, followed by low-current constant current electrolysis.

[0033] The electrolytic etching method in step S2.1 involves first performing constant current electrolysis with a high current density of 2.5-50 A / dm² for 10-50 seconds, followed by constant current electrolysis with a low current density of 1-10 A / dm² for 120-300 seconds. The high current density is 2.5-5 times that of the low current density.

[0034] The electrolytic etching method in step S2.2 involves first performing constant current electrolysis with a high current density of 1.5-50 A / dm² for 10-50 s, followed by constant current electrolysis with a low current density of 1-12.5 A / dm² for 300-1200 s. Furthermore, the high current density is 1.5-4 times that of the low current density.

[0035] In this distributed etching method, the high current in the first etching step is used to penetrate the surface of the metal substrate, serving as a selection point and increasing the hole ratio. The low current is used to increase the hole diameter. The high current in the second etching step is used to penetrate the selected point at the bottom of the hole etched in the first step for further etching, while the low current is used to increase the hole depth and achieve the final "octopus tentacles" or "anchor claw" shaped structure.

[0036] The organic acid in the microporous etching solution is one or more selected from ethylenediaminetetraacetic acid, salicylic acid, sulfosalicylic acid, citric acid, malic acid, tartaric acid, nitrilotriacetic acid, glycine, cystine, gluconic acid, lactic acid, and acetic acid. The organic acid can provide a suitable acidic environment, promoting the dissolution of titanium into titanium ions and improving etching efficiency, while avoiding excessive corrosion of the titanium alloy that could cause "corner burning."

[0037] The pH stabilizer is one or more of the following: potassium acetate, sodium acetate, ammonium acetate, propionic acid, ammonium propionate, ammonia, boric acid, borax, benzoic acid, sodium benzoate, sodium lactate, and potassium lactate. The pH stabilizer can buffer the pH of the metal surface, protecting the integrity of the etched substrate.

[0038] The dispersant is one or more of polyacrylic acid, polymaleic acid, sodium dodecylbenzenesulfonate, alkylphenol polyoxyethylene ether, polyacrylate, and sodium methylene bisnaphthalenesulfonate. The dispersant primarily disperses and adheres to titanium oxide particles within the micropores of the titanium alloy, preventing these particles from clogging the micropores and thus hindering the etching solution from further penetrating and etching the micropores.

[0039] The etchant is one or more of sodium chloride, potassium chloride, ammonium chloride, sodium hypochlorite, sodium chlorate, potassium chlorate, sodium chlorite, sodium trichloroacetate, trichloroacetic acid, dichloroacetic acid, and sodium dichloroacetate. The etchant can be a chloride, an oxychloride salt of chloride, or a chlorinated organic acid. This organic acid environment allows the etching solution to induce pitting corrosion in the titanium alloy under electrical conditions, with the corrosion points gradually expanding into micropores and being shaped under controlled conditions.

[0040] The anisotropic modifier is one or more of 2-(aminomethyl)benzoic acid, 4-[1-[(2,4-diamino-6-pteridyl)methyl]-3-butynyl]benzoic acid, 4-(carboxymethyl)-3-nitrobenzoic acid, 2-carbamoyl-3-nitrobenzoic acid, and 2-iodo-3-methoxybenzoic acid. The anisotropic modifier is an alkyl or aminobenzoic acid derivative, which adsorbs onto the inner surface of the micropores during electrolysis, improving the lateral and longitudinal etching rates. As the pore depth increases, the lateral etching rate continuously increases, causing the micropores to exhibit an "octopus-like" or "anchor-like" structure.

[0041] The solvent is one or more selected from water, ethylene glycol, propylene glycol, glycerol, sorbitol, tetrahydrofurfuryl alcohol, ethylene glycol phenyl ether, and ethylene glycol butyl ether. Mixing water with an organic solvent can improve the electric field distribution during the etching process and enhance the hole-forming effect.

[0042] This etching solution shapes the micropores on the surface of the metal substrate. A two-step etching method is preferred. The first step, or first-stage etching solution, by weight, comprises the following raw materials: 10-15 parts organic acid, 5-10 parts pH stabilizer, 10-20 parts dispersant, 24-40 parts etchant, 3-5 parts anisotropic modifier, and 30-80 parts solvent. That is, the mass ratio of the etchant to the anisotropic modifier is at least 8:1. The second step, or second-stage etching solution, by weight, comprises the following raw materials: 10-15 parts organic acid, 5-10 parts pH stabilizer, 10-20 parts dispersant, 9-30 parts etchant, 10-15 parts anisotropic modifier, and 30-80 parts solvent. The mass ratio of the etchant to the anisotropic modifier is at most 3:1.

[0043] The mass ratio of etchant to anisotropic modifier directly controls the micropore morphology during the etching process. In the first-step etching solution, when the mass ratio of etchant to anisotropic modifier is greater than 8:1, the lateral etching rate on the metal substrate surface is greater than the longitudinal etching rate, resulting in a "octopus head" or "anchor bar" shaped micropore structure with a pore size of 20-150 μm, a pore depth of 5-15 μm, and a pore ratio of 30-50%. In the second-step etching solution, when the mass ratio of etchant to anisotropic modifier is less than 3:1, based on the micropores from the first step, the longitudinal etching rate is initially greater than the lateral etching rate. After a period of time, the lateral etching rate then becomes greater than the longitudinal etching rate. After two etching steps, a micropore structure with a pore size of 20-300 μm, a pore depth of 20-200 μm, and a pore ratio of 30-90% can be formed on the metal substrate surface, with the micropores exhibiting "octopus tentacles" or "anchor claw" shapes.

[0044] In the specific etching process, optimal power supply control is preferred to form the best micropore morphology. Specifically, the electrolysis method for each etching stage is as follows: first, high-current constant-current electrolysis, followed by low-current constant-current electrolysis. Specifically, in the first etching stage, a current density of 2.5-50 A / dm² is initially used. 2 High-current constant-current electrolysis is used, with an electrolysis time of 10-50 seconds, followed by a current density of 1-10 A / dm³. 2 A low-current constant-current electrolysis is used, with an electrolysis time of 120-300 seconds. Preferably, the high-current current density in the first etching stage is 2.5-5 times the low-current current density. In the second etching stage, a current density of 1.5-50 A / dm² is initially used. 2 High-current constant-current electrolysis is used, with an electrolysis time of 10-50 seconds, followed by a current density of 1-12.5 A / dm³. 2 The process involves constant current electrolysis with a low current, lasting 300-1200 seconds. Preferably, the high current density in the second etching stage is 1.5-4 times that of the low current density. The high current in the first etching stage is used to penetrate the surface of the metal substrate, serving as a selection point and increasing the hole ratio. The low current is used to increase the hole diameter. The high current in the second etching stage is used to further etch the selected point at the bottom of the hole etched in the first stage, while the low current is used to increase the hole depth and achieve the final "octopus tentacles" or "anchor claw" shaped structure.

[0045] The plastic-coated metal component provided by this utility model includes a metal substrate 20 and a plastic layer 30. By forming micropores 10 on the surface of the metal substrate 20 and providing laterally branched extensions 13 below the micropores 10, the plastic layer 30 can fully penetrate into the micropores 10 and the lateral extensions 13 during injection molding, forming a multi-layered, multi-point mechanical locking structure. Therefore, the overall reliability of the plastic-coated metal component is high. Secondly, the ratio of the opening diameter 11 of the micropores 10 on the surface of the metal substrate 20 to the maximum diameter of the main cavity section 12 inside the hole is 0.35~0.8, so that the micropores 10 have a "reverse interlocking" geometric shape. After the plastic is cured, it is firmly embedded in the cavity, realizing a composite locking in the longitudinal and transverse directions, thereby significantly enhancing the anti-pull-out, anti-peeling, and impact resistance between the metal substrate 20 and the plastic layer 30. Meanwhile, the size, depth, and proportion of the micropores 10 are limited within a suitable range, allowing the plastic to smoothly fill each micropore 10 during injection molding without affecting the structural strength of the metal substrate 20. This achieves a reasonable balance between high bonding strength and the strength of the metal substrate 20, effectively increasing the effective contact area between the metal substrate 20 and the plastic layer 30, optimizing stress distribution, reducing local stress concentration, and significantly improving the reliability, durability, and overall structural stability of the plastic-coated metal component during long-term use. Therefore, this plastic-coated metal component can maintain excellent bonding performance under complex mechanical loads and thermal stress conditions.

[0046] The above-disclosed embodiments are merely some preferred embodiments of the present utility model, and should not be construed as limiting the scope of the present utility model. Therefore, any equivalent changes made in accordance with the scope of the present utility model patent application shall still fall within the scope of the present utility model.

Claims

1. A plastic-coated metal component, characterized in that: It includes: A metal substrate, the surface of which is provided with a plurality of micropores extending inward from the surface of the metal substrate; A plastic layer is coated on the surface of the metal substrate and penetrates into the micropores to form a mechanical interlocking connection with the metal substrate; wherein, The micropores extend inward from the surface of the metal substrate, and the ratio d0 / dmax of the opening diameter d0 of the micropore to the maximum diameter dmax of the main cavity section inside the micropore is 0.35~0.

8. The micropores have at least one laterally branched extension below their main cavity section, and the minimum diameter of the lateral extension is 1 / 3 to 1 times the opening diameter of the micropore. The opening diameter of the micropores is 20~300μm, the depth is 20~200μm, and the proportion of micropores on the surface of the metal substrate is 30%~90%.

2. The plastic-coated metal component as described in claim 1, characterized in that, The metal substrate is a titanium alloy metal workpiece, which includes titanium and its alloy metal workpieces, titanium-copper composite metal workpieces with copper shielding, titanium-steel composite metal workpieces with steel shielding, and titanium-aluminum composite metal workpieces after anodizing.

3. The plastic-coated metal component as described in claim 1, characterized in that, The plastic layer is a resin plastic layer or a thermoplastic elastomer plastic layer.

4. The plastic-coated metal component as described in claim 1, characterized in that, The micropores have an opening diameter of 20-150 μm, a pore depth of 5-15 μm, and the proportion of micropores on the surface of the metal workpiece is 30-50%.

5. The plastic-coated metal component as described in claim 1, characterized in that, The number of lateral extensions of the micropores is 2 to 16.

6. The plastic-coated metal component as described in claim 1, characterized in that, The lateral extensions are evenly distributed circumferentially around the axis of the main cavity section inside the hole.

7. The plastic-coated metal component as described in claim 1, characterized in that, The lateral extensions extend radially.

8. The plastic-coated metal component as described in claim 1, characterized in that, The end of the lateral extension that is away from the main cavity section inside the hole is hook-shaped or barbed.

9. The plastic-coated metal component as described in claim 1, characterized in that, The angle between the lateral extension and the axis of the main cavity section inside the hole is 30° to 90°.

10. The plastic-coated metal component as described in claim 1, characterized in that, The inner wall of the lateral extension is provided with multiple coral-shaped slits extending outward.

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