Metal substrate, structural member and electronic equipment

Abstract

The utility model relates to a metal base material, a structural part and electronic equipment, and relates to the technical field of metal surface treatment. The metal base material comprises a bonding layer formed on the surface of the metal base material, and the bonding layer comprises nanoscale pores; the pores comprise nano-scale micropores, and at least part of the nano-scale micropores are communicated with one another. According to the metal base material disclosed by the invention, the binding force between the metal base material and other substrate materials can be improved by forming the binding layer comprising the nano-scale pores on the surface of the metal base material.

Description

Technical Field

[0001] The present disclosure relates to the technical field of metal surface treatment, and particularly to a metal substrate, a structural member and an electronic device. Background Art

[0002] Due to the advantages of high strength, low resistance, fast heat dissipation, etc., metal materials are often used as composite materials with substrate materials such as plastics and are widely used in parts of automobiles, household appliances, and electronic products. However, due to the large difference in surface properties between metals and substrates such as plastics, the bonding force between metals and other substrate materials is poor, which greatly limits their applications in fields such as smart wearables and mobile phone casings. Summary of the Invention

[0003] To overcome the problems existing in the related art, the present disclosure provides a metal substrate and its preparation method, a structural member and its preparation method, and an electronic device.

[0004] According to the first aspect of the embodiments of the present disclosure, a metal substrate is provided. The metal substrate includes a bonding layer formed on the surface of the metal substrate, and the bonding layer includes nano-scale pores; the pores include nano-scale micropores, and at least some of the nano-scale micropores are connected to each other.

[0005] In some embodiments of the present disclosure, the ratio of the depth of the nano-scale micropores to the thickness of the bonding layer is greater than or equal to 12.75%.

[0006] In some embodiments of the present disclosure, the ratio of the depth of the nano-scale micropores to the thickness of the bonding layer is 20.05 - 56.24%.

[0007] In some embodiments of the present disclosure, the ratio of the pore diameter of the nano-scale micropores to the thickness of the bonding layer is 1.32 - 23.54%.

[0008] In some embodiments of the present disclosure, the cross-section of the bonding layer has a honeycomb structure, and the longitudinal section of the bonding layer has a fence-like structure.

[0009] In some embodiments of the present disclosure, the pore diameter of the nano-scale micropores is 20 - 200 nm, and the pore depth of the nano-scale micropores is 100 - 400 nm.

[0010] In some embodiments of the present disclosure, the metal substrate is a metal substrate including copper, aluminum, magnesium, iron, zinc, titanium or an alloy of copper, aluminum, magnesium, iron, zinc, titanium.

[0011] According to the second aspect of the embodiments of the present disclosure, a structural member is provided, including the above-mentioned metal substrate and a plastic layer, and the plastic layer is combined with the metal substrate through the bonding layer.

[0012] In some embodiments of the present disclosure, the surface of the plastic layer adjacent to the metal substrate is fitted with the bonding layer of the metal substrate.

[0013] In some embodiments of the present disclosure, the plastic layer comprises one or more of polyphenylene sulfide, polyphthalamide, and polyamide.

[0014] In some embodiments of the present disclosure, the plastic layer is a plastic layer comprising a composite material containing polyphenylene sulfide, polyphthalamide, and / or polyamide.

[0015] In some embodiments of the present disclosure, the plastic layer is a plastic layer comprising a composite material containing polyphenylene sulfide, polyphthalamide, and / or polyamide and glass fiber with a mass percentage content of 5-50%.

[0016] According to a fourth aspect of the embodiments of the present disclosure, there is provided an electronic device, comprising: a processor, an antenna module, and a housing, at least part of the housing comprising the structural member described above, the processor being communicatively connected to the antenna module, and the processor and the antenna module being at least partially defined within an accommodation space formed by surrounding of the structural member.

[0017] In some embodiments of the present disclosure, the antenna module is coupled to the metal substrate in the structural member.

[0018] The technical solutions provided by the embodiments of the present disclosure may include the following beneficial effects:

[0019] By forming a bonding layer including nano-scale pores on the surface of the metal substrate of the present disclosure, the bonding force between the metal substrate and other substrate materials can be improved.

[0020] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present disclosure and, together with the specification, are used to explain the principles of the present disclosure.

[0022] Figure 1 is a schematic flow chart of a method for preparing a metal substrate shown according to an exemplary embodiment;

[0023] Figure 2 is a schematic layer structure diagram of a metal substrate shown according to an exemplary embodiment;

[0024] Figure 3 is a schematic cross-sectional view of the micropores and through-holes structures in the bonding layer shown according to an exemplary embodiment;

[0025] Figure 4is a scanning electron microscope image of a cross-section of a bonding layer shown according to an exemplary embodiment;

[0026] Figure 5 is a scanning electron microscope image of a longitudinal section of a bonding layer shown according to an exemplary embodiment;

[0027] Figure 6 is a schematic diagram of the layer structure of a structural member shown according to an exemplary embodiment;

[0028] Figure 7 is a scanning electron microscope image of a cross-section of a bonding layer shown according to Comparative Example 1.

[0029] The meanings of the symbols in the figure are as follows:

[0030] 1. Metal substrate; 11. Bonding layer; 111. Micropores; 112. Through-holes; 2. Plastic layer. Detailed Description of the Invention

[0031] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0032] To solve the technical problem of poor bonding strength between metal and substrate materials such as plastics, the present disclosure provides a method for preparing a metal substrate. The method includes placing a metal substrate in an electrolyte and performing a primary anodization treatment under preset conditions to form a bonding layer with nanoscale pores on the surface of the metal substrate, and the pores include nanoscale micropores. The communication between at least some of the nanoscale micropores can improve the bonding strength between the metal substrate and other substrate materials, thereby improving the mechanical properties of the composite material formed by the metal and other substrate materials.

[0033] In an exemplary embodiment, as Figure 1 shown, the present disclosure provides a method for preparing a metal substrate, including:

[0034] S110. Place a metal substrate in an electrolyte and perform a primary anodization treatment under preset conditions to form a bonding layer on the surface of the metal substrate, obtaining a metal substrate; the pores include nanoscale micropores, and at least some of the nanoscale micropores communicate with each other.

[0035] In this embodiment, by the method of anodization, nanoscale pores can be formed on the surface of the metal substrate to improve the bonding strength between the metal substrate and other substrate materials.

[0036] When the materials of the metal substrates are different, the formulation of the electrolyte can be adjusted adaptively. Among them, when the metal substrate is powder metallurgy titanium alloy (MiM-TC4), due to the presence of micropores, metal carbonitrides and other impurities inside MiM-TC4, these defects make it difficult for MiM-TC4 to form an interconnected microporous structure through traditional metal surface treatment methods, making it difficult to achieve plastic-metal integration molding for such materials. The main reason is that when performing metal surface treatment on MiM-TC4, if the method of forming a titanium alloy conversion film is adopted, only a gully structure can be formed on the surface of the titanium alloy substrate. This gully structure can be used as the carrier on the surface of a general thin film coating and has a certain bonding force. However, the bonding force between this conversion film and other substrate materials is poor, and it is difficult to meet the strength requirements for forming an integrated structure with engineering plastics. In addition, due to the nature of MiM-TC4 itself, it cannot generate a nanoscale porous bonding layer during anodic oxidation like aluminum alloy, its surface activity is very poor, and since the surface chemical properties of titanium metal are extremely active, the formed oxidative bonding layer is not firmly bonded to the titanium metal substrate. Therefore, during nano-injection molding, there is basically no bonding force between titanium and plastic, and they are easily debonded and separated.

[0037] In order to solve the above technical problems, in an exemplary embodiment, the present disclosure provides an electrolyte, which includes the following raw materials: 1-20 mL / L of hydrofluoric acid or acid salt of hydrofluoric acid, 200-400 g / L of inorganic acid, 100-200 mL / L of surfactant, and the balance is water.

[0038] The electrolyte of this embodiment can overcome the problem that MiM-TC4 is difficult to be treated by anodic oxidation through the cooperation of hydrofluoric acid or acid salt of hydrofluoric acid with inorganic acid and surfactant, so that interconnected micropores can be formed on the MiM-TC4 substrate. Thus, the bonding force between titanium alloy and plastic can be improved while reducing production costs.

[0039] It should be noted that the electrolyte of this embodiment is not limited to metal substrates made of powder metallurgy titanium alloy, and is also applicable to metals such as copper, aluminum, magnesium, iron, zinc, or alloys of copper, aluminum, magnesium, iron, zinc, etc. that are suitable for forming an oxide film layer by anodic oxidation method. For different materials of metal substrates, the ratios of hydrofluoric acid or acid salt of hydrofluoric acid to inorganic acid and surfactant can be adjusted adaptively to form nanoscale pores on different metal substrates.

[0040] Exemplarily, the electrolyte includes the following raw materials: 1 mL / L of hydrofluoric acid, 200 g / L of inorganic acid, 100 mL / L of surfactant, and the balance is water.

[0041] Exemplarily, the electrolyte comprises the following raw materials: 10 mL / L of hydrofluoric acid salt, 300 g / L of inorganic acid, 150 mL / L of surfactant, and the balance is water.

[0042] Exemplarily, the electrolyte comprises the following raw materials: 20 mL / L of hydrofluoric acid salt, 400 g / L of inorganic acid, 200 mL / L of surfactant, and the balance is water.

[0043] In an exemplary embodiment, the acid salt of hydrofluoric acid comprises a composition of one or more of sodium hydrogen fluoride, potassium hydrogen fluoride, and ammonium hydrogen fluoride.

[0044] In this embodiment, in order to improve the safety of operation, the acid salt of hydrofluoric acid can be used as the raw material of the electrolyte. The acid salt of hydrofluoric acid can be sodium hydrogen fluoride, potassium hydrogen fluoride, or ammonium hydrogen fluoride.

[0045] Exemplarily, the electrolyte comprises the following raw materials: 1-20 mL / L of ammonium hydrogen fluoride, 200-400 g / L of inorganic acid, 100-200 mL / L of surfactant, and the balance is water. Since sodium hydrogen fluoride and potassium hydrogen fluoride contain metal ions sodium ions and potassium ions respectively, when sodium hydrogen fluoride or potassium hydrogen fluoride is used as the raw material of the electrolyte, after pores are formed on the surface of the metal substrate, sodium ions or potassium ions are likely to remain in the pores, affecting the subsequent bonding of the metal substrate with other substrate materials. Therefore, ammonium hydrogen fluoride can be used as the raw material of the electrolyte, which is beneficial to forming nano-scale pores without impurity residues on the surface of the metal substrate.

[0046] In an exemplary embodiment, the inorganic acid comprises a composition of one or more of sulfuric acid, phosphoric acid, nitric acid, oxalic acid, and chromic acid.

[0047] In this embodiment, the inorganic acid can be only sulfuric acid, or a composition of sulfuric acid and phosphoric acid. Exemplarily, the inorganic acid comprises 100 g / L of sulfuric acid and 150 g / L of phosphoric acid.

[0048] In an exemplary embodiment, the surfactant comprises a composition of one or more of tartaric acid, acetic acid, citric acid, and hydrogen peroxide.

[0049] In this embodiment, the surfactant can be tartaric acid, or a mixture of tartaric acid and hydrogen peroxide. Exemplarily, the surfactant is 50 mL / L of tartaric acid and 50 mL / L of hydrogen peroxide.

[0050] In an exemplary embodiment, the preset conditions include: maintaining at a voltage of 10-22.5 V for 5-40 min.

[0051] In this embodiment, by adjusting the voltage and time of anodic oxidation, the size of the pores can be adjusted.

[0052] Exemplarily, the preset conditions include: maintaining at a voltage of 10V for 5 minutes.

[0053] Exemplarily, the preset conditions include: maintaining at a voltage of 16V for 20 minutes.

[0054] Exemplarily, the preset conditions include: maintaining at a voltage of 18V for 25 minutes.

[0055] Exemplarily, the preset conditions include: maintaining at a voltage of 20V for 40 minutes.

[0056] Exemplarily, the preset conditions include: maintaining at a voltage of 22.5V for 40 minutes.

[0057] In one exemplary embodiment, before placing the metal substrate in the electrolyte, the preparation method further includes: preprocessing the metal substrate, and the preprocessing includes: degreasing, acid etching, and activation.

[0058] In this embodiment, in order to ensure the bonding strength between the bonding layer and the metal substrate, before placing the metal substrate in the electrolyte, the metal substrate can also be degreased, acid etched, and activated. Among them, degreasing is to remove oil and the like on the surface of the metal substrate. Acid etching is to remove the oxide scale and contaminants on the surface layer of the metal substrate to obtain a uniform surface. Activation is to remove the oxide film layer generated on the surface of the metal substrate in the previous process while delaying the occurrence of secondary oxidation to improve the bonding strength between the bonding layer obtained by anodic oxidation treatment and the metal substrate.

[0059] It can be understood that in order to avoid the influence of the previous process on the subsequent process, a cleaning process can be added between each process. For example, a cleaning operation can be added between acid etching and activation. An ash removal process can also be added between acid etching and activation to remove a layer of floating ash remaining on the metal surface.

[0060] Among them, degreasing, acid etching, and activation can adopt the methods in the prior art, and corresponding degreasing, acid etching, and activation methods are selected according to the different metal materials. For example, soak the titanium alloy in acetone for 30 minutes to degrease the titanium alloy, and wash the surface of the titanium alloy with clean water. Then soak the degreased titanium alloy in concentrated hydrochloric acid (37%) for 5 minutes for acid etching, and wash the surface of the titanium alloy with clean water. Then place the titanium alloy after ash removal in the activation solution (including 70g / L of sulfuric acid and 10g / L of sodium fluoride), soak it at a temperature of 25°C for 90s, and wash the surface of the titanium alloy with clean water.

[0061] In one exemplary embodiment, the present disclosure provides a metal substrate, such as Figure 2 and Figure 3As shown, the metal substrate 1 includes a bonding layer 11 formed on the surface of the metal substrate 1. The bonding layer 11 includes nano-scale pores; the pores include nano-scale micropores 111, and at least some of the nano-scale micropores 111 communicate with each other. In Figure 2 an example, the bonding layer 11 formed on the metal substrate 1 is shown. In Figure 2 an example, the bonding layer 11 and other parts of the metal substrate 1 are schematically distinguished by a dotted line. It should be noted that in an actual product, the boundary between the bonding layer 11 and other parts of the metal substrate 1 is not necessarily obvious. For example, the characteristics of the bonding layer 11 may gradually weaken to form the metal substrate 1 including the bonding layer 11.

[0062] In this embodiment, the bonding layer 11 can be formed on the surface of the metal substrate by physical methods, chemical corrosion, electro-chemical reaction, etc. At least some of the nano-scale micropores 111 communicate with each other, so that the strong adsorption characteristics formed by the surface energy of the bonding layer 11 can form a bond with other substrate materials (such as plastics) through non-metallic or organic functional groups generated by chemical or physical filling, thereby improving the bonding force between the metal substrate 1 and other substrate materials.

[0063] Among them, at least some of the nano-scale micropores 111 communicate with each other. For example, two adjacent nano-scale micropores 111 may communicate with each other. For example, a through hole 112 may be formed between two adjacent nano-scale micropores 111, or three or more nano-scale micropores 111 may communicate with each other. For example, among three or more nano-scale micropores 111, a through hole 112 is formed between two adjacent nano-scale micropores 111 to form the communication between some of the nano-scale micropores in the pores. It can also be that all the nano-scale micropores 111 communicate with each other. For example, a through hole 112 is formed between any two adjacent nano-scale micropores 111 to form that all the micropores 111 in the entire pores communicate with each other. The nano-scale micropores 111 in the bonding layer 11 penetrate each other partially or completely, so that the bonding layer 11 of the metal substrate 1 obtained has a good bonding force with other substrate materials. For example, when the metal and plastic are integrally formed by the nano-injection molding process, through the mutually penetrating nano-scale micropore structure, it is beneficial to exhaust air during injection molding and also facilitates the mutual penetration and biting of plastics between the micropores to avoid the separation between the metal substrate 1 and the plastic, thereby improving the mechanical properties of the metal-plastic material.

[0064] In an exemplary embodiment, the ratio of the depth of the nano-scale micropores to the thickness of the bonding layer 11 is 20.05%-56.24%.

[0065] In this embodiment, the ratio of the depth of the nano-scale micropores to the thickness of the bonding layer 11 is 20.05-56.24%, and the metal substrate has a relatively high bonding force with other substrate materials.

[0066] Exemplarily, the ratio of the depth of the nanoscale micropores to the thickness of the bonding layer 11 is 20.05%, 28.54%, 36.43%, 43.58%, 56.24%.

[0067] In one exemplary embodiment, the ratio of the pore diameter of the nanoscale micropores to the thickness of the bonding layer 11 is 1.32 - 23.54%.

[0068] In this embodiment, by controlling the ratio of the depth of the nanoscale micropores to the thickness of the bonding layer 11 and the ratio of the pore diameter of the nanoscale micropores to the thickness of the bonding layer 11, the bonding force between the metal substrate and other substrate materials can be further improved.

[0069] Exemplarily, the ratio of the pore diameter of the nanoscale micropores to the thickness of the bonding layer 11 is 1.32%, 7.43%, 14.56%, 23.54%.

[0070] In one exemplary embodiment, the cross-section of the bonding layer 11 has a honeycomb structure, and the longitudinal section of the bonding layer 11 has a fence-like structure.

[0071] In this embodiment, as Figure 4 shown, the cross-section of the bonding layer 11 has a honeycomb structure, and this cross-section can be a regularly arranged honeycomb structure or an irregularly arranged honeycomb structure. Figure 4 The honeycomb structure illustrated in is a regular honeycomb structure. As Figure 5 shown, the longitudinal section of the bonding layer 11 has a fence-like structure, where label 1 is the metal substrate and label 11 is the bonding layer, and the bonding layer 11 is formed on the surface of the metal substrate 1. This longitudinal section can be a regularly arranged fence-like structure or an irregularly arranged fence-like structure. Figure 5 What is illustrated is an irregularly arranged fence-like structure.

[0072] In one exemplary embodiment, the pore diameter of the nanoscale micropores 111 is 20 - 200 nm, and the pore depth of the nanoscale micropores 111 is 100 - 400 nm.

[0073] When the pore diameter of the nanoscale micropores 111 is too small, moisture, air, etc. retained in the micropores due to moisture absorption and other reasons are difficult to discharge from the micropores, and it is difficult for other substrate materials to enter the nanoscale micropores 111, which will affect the bonding force between the metal substrate 1 and other substrate materials; when the pore diameter of the nanoscale micropores 111 is too large, other substrate materials are easily detached from the nanoscale micropores, resulting in a decrease in the biting force between the metal material and other substrate materials.

[0074] In some exemplary embodiments, the pore diameter 111 of the nanoscale micropores may also be 60 - 100 nm, and the pore depth of the nanoscale micropores 111 may also be 200 - 300 nm. Exemplarily, the pore diameter of the nanoscale micropores 111 is 60 nm, 80 nm, 100 nm, and the pore depth of the nanoscale micropores 111 is 200 nm, 250 nm, 300 nm.

[0075] In one exemplary embodiment, the metal substrate 1 includes copper, aluminum, magnesium, iron, zinc, titanium, or an alloy of copper, aluminum, magnesium, iron, zinc, and titanium.

[0076] In this embodiment, according to the different materials of the metal substrate 1, different metal surface treatment methods can be adopted to form the bonding layer 11 on the surface of the metal substrate 1. For example, the nanoscale pores can be formed by nano-injection molding. Among them, when the metal substrate 1 is a titanium alloy, profile titanium alloy TC4 and powder metallurgy titanium alloy can be used. Profile titanium alloy is generally made by forging and computerized numerical control (CNC) and other methods, and it has the advantages of high specific strength, high corrosion resistance, and light weight. Powder metallurgy titanium alloy is a titanium alloy material made by metal powder injection molding (MiM). Compared with profile titanium alloy, MiM-TC4 has the advantage of low processing cost, which can greatly reduce the production cost.

[0077] In one exemplary embodiment, the present disclosure provides a structural member, such as Figure 6 shown, including a metal substrate 1 and a plastic layer 2, and the plastic layer 2 is combined with the metal substrate 1 through the bonding layer 11. In Figure 6 it, the bonding layer 11 formed on the metal substrate 1 and the plastic layer 2 combined with the bonding layer 11 are exemplarily shown. In Figure 6 it, the bonding layer 11 is schematically distinguished from other parts of the metal substrate 1 by a dashed line, and the bonding layer 11 and the plastic layer 2 are schematically distinguished by a dashed line. It should be noted that the attached Figure 6This is only a schematic diagram showing the relative positional relationship between the metal substrate 1 and the plastic layer 2, and does not limit the connection method between the bonding layer 11 and the plastic layer 2 or the shape of the bonding surface between the bonding layer 11 and the plastic layer 2. In an actual product, the boundary between the bonding layer 11 and the other parts of the metal substrate 1 is not necessarily obvious. For example, the characteristics of the bonding layer 11 can gradually weaken to form the metal substrate 1 including the bonding layer 11. The boundary between the bonding layer 11 and the plastic layer 2 can be zigzag or straight. For example, the plastic layer 2 can enter the pores of the bonding layer 11 to form an interlocking bonding surface; the plastic layer 2 can also be only on the surface of the bonding layer 11 without entering the pores of the bonding layer 11. In this embodiment, the bonding layer 11 on the surface of the metal substrate 1 can improve the bonding force between the metal substrate 1 and the plastic layer 2.

[0078] In an exemplary embodiment, the surface of the plastic layer 2 close to the metal substrate 1 is fitted with the bonding layer 11 of the metal substrate 1.

[0079] In this embodiment, the plastic layer 2 can enter the pores of the bonding layer 11 of the metal substrate 1 and thus be fitted with the bonding layer 11 to improve the bonding force between the metal substrate 1 and the plastic layer 2.

[0080] In an exemplary embodiment, the plastic layer 2 includes one or both of polyphenylene sulfide and polyphthalamide, and / or a composite material containing polyphenylene sulfide and / or polyphthalamide.

[0081] In this embodiment, the plastic layer 2 can be polyphenylene sulfide (PPS), polyphthalamide (PPA), and / or polyamide (PA). The above materials have the advantages of high mechanical strength, good chemical resistance, and good thermal stability; it can also be a composite material containing PPS, PPA, and PA. For example, PPS or PPA is reinforced and toughened by inorganic fibers, inorganic fillers, etc.

[0082] In an exemplary embodiment, the composite material containing polyphenylene sulfide, polyphthalamide, and / or polyamide further includes glass fiber, and the mass percentage content of the glass fiber is 5-50%. In some exemplary embodiments, the mass percentage content of the glass fiber can also be 20-30%.

[0083] In this embodiment, glass fiber (GF) can enhance PPS, PPA, and PA to improve the mechanical strength of the plastic layer 2. When the content of glass fiber is relatively high, its enhancement effect on PPS, PPA, or PA is better. However, due to the relatively large fiber diameter of glass fiber, when the content of glass fiber is too high (for example, exceeding 50%), it will be difficult for the PPS / GF, PPA / GF, or PA / GF composite material to completely enter the pores of the bonding layer 11, resulting in a decrease in the bonding strength of the bonding layer 11 between it and the metal substrate 1.

[0084] Exemplarily, in the PPS composite material, PPA composite material, or PA composite material, the mass percentage content of glass fiber is 5%, 20%, 30%, 40%, or 50%.

[0085] In an exemplary embodiment, the residual glue amount of the thrust on the bonding surface between the metal substrate 1 and the plastic layer 2 is 80 - 100%.

[0086] In this embodiment, when a thrust test is performed on the structural member, the residual glue amount of the thrust on the bonding surface between the metal substrate 1 and the plastic layer 2 is 80 - 100%, indicating that when the structural member is subjected to a shear force, 80 - 100% of the plastic layer 2 can still remain on the surface of the metal substrate 1, indicating that there is a good bonding force between the plastic layer 2 and the metal substrate 1.

[0087] In an exemplary embodiment, the fracture strength of the structural member is greater than 550N.

[0088] In this embodiment, when a thrust test is performed on the structural member, the fracture strength of the structural member is greater than 550N, indicating that the peel strength between the metal substrate 1 and the plastic layer 2 is much greater than 550N. Before the plastic layer 2 breaks, the plastic layer 2 has not separated from the metal substrate 1, thus indicating that there is an excellent bonding strength between the metal substrate 1 and the plastic layer 2.

[0089] In an exemplary embodiment, the airtightness leakage value of the housing substrate is -20 - 100Pa.

[0090] Different products have different requirements for the waterproof level. Since the molecules of air are smaller than those of water molecules, airtightness detection is generally used. For example, smart wearable watches generally require a waterproof level of 5 - 10ATM. 5ATM means that the waterproof pressure level of the product is 5 atmospheres, that is, 50 meters waterproof. The airtightness leakage value of the housing substrate in this embodiment is -20 - 100Pa, which can meet the waterproof level requirements of 5ATM.

[0091] In an exemplary embodiment, the present disclosure provides a method for manufacturing a structural member, and the structural member is made by a nano-injection molding process.

[0092] In this embodiment, the structural member can be made by nano-injection molding process. Nano-injection molding refers to Nano Molding Technology (NMT), which is a process of combining metal and plastic with nanotechnology. That is, after the metal surface is nano-treated to form a bonding layer with nano-scale pores, the plastic is directly injection-molded on the metal surface, so that the metal and the plastic can be integrally formed. The nano-injection molding process adopted in this embodiment can adopt the methods in the prior art and will not be specifically limited herein.

[0093] In an exemplary embodiment, the present disclosure provides an electronic device, including: a processor, an antenna module, and a housing. At least part of the housing includes the above-mentioned structural member. The processor is communicatively connected to the antenna module, and the processor and the antenna module are at least partially defined within a receiving space formed by the surrounding of the structural member.

[0094] In this embodiment, the electronic device is, for example, a mobile phone, a laptop computer, a tablet computer, a wearable device, etc. Among them, the structural member forms the housing. The housing can be integrally formed or composed of multiple parts. In this case, at least one part of the multiple parts is the structural member.

[0095] When the structural member is used for the housing of the electronic device, an antenna break point for accommodating the antenna module is provided on the structural member. Since the bonding layer 11 is provided on the surface of the metal substrate 1 in the structural member, strong bonding between the two heterogeneous materials of the metal substrate 1 and the plastic layer 2 can be achieved. When an antenna break point is provided on the structural member, the metal substrate 1 and the plastic layer 2 can still maintain a high bonding strength.

[0096] In an exemplary embodiment, the antenna module is coupled to the metal substrate 1 in the structural member.

[0097] Among them, the antenna module and the metal substrate 1 in the structural member can be directly connected or coupled with a gap.

[0098] In order to more clearly explain the technical solution of the present disclosure, specific embodiments of the preparation method of the structural member are listed in the present disclosure. The beneficial effects of selecting the above ranges of the contents of each component and the process parameters will be illustrated by specific experimental data through specific embodiments. It should be noted that the raw material components, contents, and process parameters of the embodiments of the present disclosure do not limit the protection scope of the present disclosure.

[0099] Example 1

[0100] A preparation method of a structural member includes the following steps:

[0101] (1) According to the design of the housing structure of the electronic device product, use the MiM method to mold the TC4 powder to obtain a metal substrate.

[0102] (2) After subjecting the metal substrate to degreasing, acid etching, ash removal, and activation treatments respectively, a pretreated metal substrate is obtained.

[0103] (3) The pretreated metal substrate is used as the anode and placed in the electrolyte solution, with stainless steel as the cathode. At a voltage of 10 V, it is maintained for 5 min to form a bonding layer on the surface of the metal substrate, obtaining a metal base material; the bonding layer includes nano-scale pores, and the pores are nano-scale micropores, and through holes are formed between any two adjacent nano-scale micropores; wherein, the electrolyte solution includes the following raw materials: ammonium bifluoride 1.1 mL / L, sulfuric acid 200 g / L, phosphoric acid 200 g / L, hydrogen peroxide 200 mL / L, and the balance is water.

[0104] (4) The metal base material is cleaned with pure water (conductivity of 1.0 ms / cm) and dried; then, the plastic is injection-molded onto the metal base material by nano-injection molding technology to form a plastic layer on the surface of the metal base material where the bonding layer is provided, obtaining a structural member; wherein, the plastic is PPS5%GF, that is, 5 wt% of GF is filled in PPS.

[0105] To more clearly explain and illustrate the technical solutions of the present disclosure, the present disclosure also lists Examples 2-17 of the structural member by changing the electrolyte formula, anodic oxidation conditions, and plastic types. Among them, the formulas and process parameters of Examples 2-9 are shown in Table 1, and the formulas and process parameters of Examples 10-17 are shown in Table 2. It should be noted that in Examples 1-17, except for the different parameters listed in Table 1 and Table 2, other parameters are basically the same.

[0106] Table 1 Process parameters of Examples 1-9

[0107]

[0108] Table 2 Process parameters of Examples 10-17

[0109]

[0110] Comparative Example 1

[0111] A method for preparing a structural member, comprising the following steps:

[0112] (1) According to the design of the housing structure of the electronic device product, the TC4 powder is formed by the MiM method to obtain a metal substrate.

[0113] (2) After subjecting the metal substrate to degreasing, acid etching, ash removal, and activation treatments respectively, a pretreated metal substrate is obtained.

[0114] (3) Place the pretreated metal substrate as the anode into the electrolyte solution, use stainless steel as the cathode, and keep it at a voltage of 18 V for 20 min to form a bonding layer on the surface of the metal substrate, thus obtaining a metal base material; wherein, the electrolyte solution includes the following raw materials: 200 g / L of sulfuric acid, 200 g / L of phosphoric acid, 150 mL / L of hydrogen peroxide, and the balance is water.

[0115] (4) Wash the metal base material with pure water (conductivity is 1.0 ms / cm) and dry it; then use the nano-injection molding process to inject plastic onto the metal base material to form a plastic layer on the surface of the metal base material where the bonding layer is provided, thus obtaining a structural member; wherein, the plastic is PPS20%GF, that is, the PPS is filled with 20 wt% of GF.

[0116] Performance testing

[0117] Prepare structural members as samples according to the methods of Examples 1-17 and Comparative Example 1 respectively, and conduct airtightness testing and thrust fracture performance testing on the above samples; wherein, the number of samples input for each airtightness test is 100. If the gas leakage value of the sample is within -20 to 100 Pa, it is recorded as qualified. If the gas leakage value of the sample is less than -20 Pa or greater than 100 Pa, it is recorded as unqualified, and calculate the airtightness defect rate of the sample. Among them, record the test results of Examples 1-9 in Table 3, and record the test results of Examples 10-17 and Comparative Example 1 in Table 4.

[0118] Table 3 Performance test table of Examples 1-9

[0119]

[0120] Table 4 Performance test table of Examples 10-17 and Comparative Example 1

[0121]

[0122] It can be seen from the data in Table 3 and Table 4 that the structural members prepared by using Examples 1-17 of the present disclosure have good airtightness. Among them, the airtightness defect rate within -20 to 100 Pa is less than 5%, the residual glue amount of thrust is greater than 80%, and the fracture strength is greater than 550 N, which can meet the requirements of the 5 ATM waterproof grade.

[0123] As Figure 7 shown, the bonding layer in Comparative Example 1 is a gully structure, rather than the mutually penetrating microporous structure in the examples. Therefore, the bonding force between the metal base material and the plastic layer is poor. When conducting airtightness testing, it is difficult to reach the 5 ATM waterproof grade. When conducting thrust fracture performance testing, before the plastic layer fractures, the plastic layer and the metal base material have already separated, resulting in the inability to measure the fracture strength of the sample.

[0124] Examples 1-9 are listed in Table 1. In Examples 1-9, the anodizing conditions and the type of plastic remain unchanged, while the components and contents of the electrolyte are different. Combining Table 1 and Table 3, it can be seen that when the component content of the electrolyte changes, the pore structure of the bonding layer formed on the surface of the metal substrate will also change accordingly, thus affecting its bonding strength with the plastic layer and further affecting the airtight performance of the product.

[0125] Among them, when the content of ammonium bifluoride is 1.0 - 5.1 mL / L, the content of sulfuric acid is 200 - 380 g / L, the content of phosphoric acid is 0 - 200 g / L, and the content of the surfactant hydrogen peroxide is 180 - 200 mL / L, the average pore diameter of the pores in the bonding layer formed on the surface of the metal substrate is 20 - 45 nm, and the average pore depth of the pores in the bonding layer is 100 - 150 nm; the airtight failure rate of the structural member formed by the metal substrate and the plastic layer thus obtained is less than 4% at -20 to 100 Pa, the residual glue amount of the thrust is greater than 80%, and the breaking strength is greater than 550 N.

[0126] When the content of ammonium bifluoride is 5.2 - 10.0 mL / L, the content of sulfuric acid is 100 - 150 g / L, the content of phosphoric acid is 100 - 150 g / L, and the content of the surfactant hydrogen peroxide is 100 - 150 mL / L, the average pore diameter of the pores in the bonding layer formed on the surface of the metal substrate is 28 - 50 nm, and the average pore depth of the pores in the bonding layer is 130 - 170 nm; the airtight failure rate of the structural member formed by the metal substrate and the plastic layer thus obtained is less than 3% at -20 to 100 Pa, the residual glue amount of the thrust is greater than 82%, and the breaking strength is greater than 550 N.

[0127] When the content of ammonium bifluoride is 10.1 - 15.2 mL / L, the content of sulfuric acid is 100 - 150 g / L, the content of phosphoric acid is 100 - 200 g / L, and the content of the surfactant hydrogen peroxide is 100 - 150 mL / L, the average pore diameter of the pores in the bonding layer formed on the surface of the metal substrate is 35 - 60 nm, and the average pore depth of the pores in the bonding layer is 130 - 180 nm; the airtight failure rate of the structural member formed by the metal substrate and the plastic layer thus obtained is less than 3% at -20 to 100 Pa, the residual glue amount of the thrust is greater than 82%, and the breaking strength is greater than 550 N.

[0128] When the content of ammonium bifluoride is 15.3 - 20.0 mL / L, the content of sulfuric acid is 100 - 150 g / L, the content of phosphoric acid is 150 - 200 g / L, and the content of surfactant hydrogen peroxide is 100 - 150 mL / L, the average pore diameter of the pores in the bonding layer formed on the surface of the metal substrate is 40 - 70 nm, and the average pore depth of the pores in the bonding layer is 180 - 190 nm; the airtightness failure rate of the structural member formed by the metal substrate and the plastic layer thus obtained is less than 1.3% at -20 to 100 Pa, the residual glue amount of the thrust is greater than 86%, and the breaking strength is greater than 560 N.

[0129] Examples 10 - 13 are listed in Table 2. In Examples 10 - 13, the electrolyte formula and the type of plastic remain unchanged, while the anodic oxidation conditions are different. Combining Table 2 and Table 4, it can be seen that when the anodic oxidation conditions change, the pore structure of the bonding layer formed on the surface of the metal substrate will also change accordingly, thus affecting its bonding force with the plastic layer and further affecting the airtight performance of the product.

[0130] When the anodic oxidation voltage is 10 - 15 V and the treatment time is 5 - 20 min, the average pore diameter of the pores in the bonding layer formed on the surface of the metal substrate is 66 - 76 nm, and the average pore depth of the pores in the bonding layer is 190 - 220 nm; the airtightness failure rate of the structural member formed by the metal substrate and the plastic layer thus obtained is less than 1.3% at -20 to 100 Pa, the residual glue amount of the thrust is greater than 88%, and the breaking strength is greater than 570 N.

[0131] When the anodic oxidation voltage is 16 - 22.5 V and the treatment time is 15 - 40 min, the average pore diameter of the pores in the bonding layer formed on the surface of the metal substrate is 70 - 100 nm, and the average pore depth of the pores in the bonding layer is 200 - 307 nm; the airtightness failure rate of the structural member formed by the metal substrate and the plastic layer thus obtained is 0% at -20 to 100 Pa, the residual glue amount of the thrust is 100%, and the breaking strength is greater than 560 N.

[0132] Examples 14 - 17 are listed in Table 2. In Examples 14 - 17, the electrolyte formula and the anodic oxidation conditions remain unchanged, while the type of plastic is different. Combining Table 2 and Table 4, it can be seen that when the content of glass fiber in the plastic changes, the airtightness of the structural member will change; when the content of glass fiber in the plastic layer is relatively high, there is a floating fiber accumulation between the plastic layer and the bonding layer, which will lead to a decrease in the bonding force between the plastic layer and the bonding layer, thus affecting the airtightness of the structural member.

[0133] When the mass percentage content of glass fiber in the plastic is 5 - 20%, the airtightness failure rate of the structural member formed by the metal substrate and the plastic layer is 0% at -20 to 100 Pa, the residual glue amount of the thrust is 100%, and the breaking strength is greater than 580 N.

[0134] When the mass percentage content of glass fiber in the plastic is 21 - 50%, the airtightness failure rate of the structural member formed by the metal substrate and the plastic layer at -20 to 100 Pa is less than 2.0%, the residual glue amount of the thrust is greater than 88%, and the breaking strength is greater than 650 N.

[0135] It should be noted that in Tables 1 and 2, examples of the electrolyte include embodiments where the hydrofluoric acid salt is ammonium bifluoride, the inorganic acid is sulfuric acid, phosphoric acid, and the surfactant is hydrogen peroxide, but this is not a specific limitation on the hydrofluoric acid salt, inorganic acid, and surfactant. When the hydrofluoric acid salt is potassium bifluoride or sodium bifluoride, the inorganic acid is nitric acid, oxalic acid, or chromic acid, and the surfactant is tartaric acid, acetic acid, citric acid, etc., the performance parameters of the metal substrate and the structural member formed by any value within the range of the above electrolyte component contents can also meet the performance change trends in Tables 3 and 4.

[0136] In order to explore the effects of the electrolyte formula, anodic oxidation conditions, and plastic type on the product performance. The present disclosure adopts a single-factor analysis method. In Examples 1 - 9, Examples 10 - 13, and Examples 14 - 17 in Table 1, other factors are kept unchanged, and only the electrolyte formula, anodic oxidation conditions, or plastic type is changed to detect the performance of the obtained samples. It should be understood that when the electrolyte formula of Example 1 - 9 is adopted, the performance parameters of the metal substrate and the structural member formed by any value within the range of the anodic oxidation conditions of Example 10 - 13 or the range of the plastic type of Example 14 - 17 can also meet the performance change trends in Tables 3 and 4.

[0137] For example, when the content of ammonium bifluoride is 1.0 - 10.0 mL / L, the content of sulfuric acid is 150 - 380 g / L, the content of phosphoric acid is 0 - 200 g / L, the content of the surfactant hydrogen peroxide is 150 - 200 mL / L; the voltage of anodic oxidation is 10 - 15 V, the treatment time is 5 - 20 min; when the mass percentage content of glass fiber in the plastic is 5 - 20%; the average pore diameter of the pores in the bonding layer formed on the surface of the metal substrate is 35 - 55 nm, and the average pore depth of the pores in the bonding layer is 140 - 180 nm; the airtightness failure rate of the structural member formed by the obtained metal substrate and the plastic layer at -20 to 100 Pa is less than 1%, the residual glue amount of the thrust is greater than 90%, and the breaking strength is greater than 580 N.

[0138] When the content of ammonium bifluoride is 10.1 - 20.0 mL / L, the content of sulfuric acid is 100 - 150 g / L, the content of phosphoric acid is 150 - 200 g / L, and the content of the surfactant hydrogen peroxide is 100 - 150 mL / L; when the voltage of anodic oxidation is 16 - 22.5 V and the treatment time is 15 - 40 min; when the mass percentage of glass fiber in the plastic is 21 - 50%; the average pore diameter of the pores in the bonding layer formed on the surface of the metal substrate is 45 - 70 nm, and the average pore depth of the pores in the bonding layer is 180 - 190 nm; the airtightness failure rate of the structural member formed by the metal substrate and the plastic layer thus obtained is less than 1.5% at -20 to 100 Pa, the residual glue amount of the thrust is greater than 88%, and the fracture strength is greater than 620 N.

[0139] In order to further verify the airtightness of the structural member of Example 14 of the present disclosure under harsh conditions, the structural member prepared in Example 8 was used as a test sample. After being processed by CNC, polishing, and Physical Vapor Deposition (PVD) processes respectively, and after being processed under harsh conditions of acid-base sweat immersion, high temperature and cold / hot and cold shock, and drop test respectively, the gas leakage value of the test sample was measured; among them, the number of tests for each sample was 12; the test results were recorded in Table 5.

[0140] Table 5 Gas leakage value of the structural member of Example 14 (unit: Pa)

[0141]

[0142] According to the data in Table 5, it can be seen that for the structural member prepared in Example 14, after being processed by CNC, polishing, and PVD processes respectively, and after being processed under harsh conditions of acid-base sweat immersion, high temperature and cold / hot and cold shock, and drop test respectively, its gas leakage value is within -20 to 100 Pa, indicating that the structural member of Example 14 has good airtightness and can meet the waterproof grade requirement of 5 ATM.

[0143] Those skilled in the art will readily think of other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. The present disclosure is intended to cover any variations, uses, or adaptations of the present disclosure, which follow the general principles of the present disclosure and include the common general knowledge or conventional technical means in the technical field not disclosed in the present disclosure. The specification and examples are only regarded as exemplary, and the true scope and spirit of the present disclosure are pointed out by the claims.

[0144] It should be understood that the present disclosure is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present disclosure is only limited by the appended claims.

Claims

1. A metal substrate, characterized in that, The metal substrate includes a bonding layer formed on the surface of the metal substrate, and the bonding layer includes nano-scale pores; the pores include nano-scale micropores, and at least some of the nano-scale micropores communicate with each other; The ratio of the depth of the nano-scale micropores to the thickness of the bonding layer is greater than or equal to 12.75%.

2. The metal substrate according to claim 1, wherein The ratio of the depth of the nano-scale micropores to the thickness of the bonding layer is 20.05 - 56.24%.

3. The metal substrate according to claim 1, characterized in that, The ratio of the pore diameter of the nano-scale micropores to the thickness of the bonding layer is 1.32 - 23.54%.

4. The metal substrate according to claim 1, wherein The cross-section of the bonding layer has a honeycomb structure, and the longitudinal section of the bonding layer has a fence-like structure.

5. The metal substrate according to claim 1, characterized in that, The pore diameter of the nano-scale micropores is 20 - 200 nm, and the pore depth of the nano-scale micropores is 100 - 400 nm.

6. A structural member, characterized in that, It includes the metal substrate and a plastic layer according to any one of claims 1 - 5, and the plastic layer is combined with the metal substrate through the bonding layer.

7. The structural member according to claim 6, wherein The surface of the plastic layer close to the metal substrate is fitted with the bonding layer of the metal substrate.

8. An electronic device, characterized in that, It includes: A processor, an antenna module, and a housing. At least part of the housing includes a structural member according to any one of claims 6 - 7. The processor is communicatively connected to the antenna module, and the processor and the antenna module are at least partially defined within a receiving space formed by the surrounding of the structural member.

9. The electronic device according to claim 8, wherein The antenna module is coupled to the metal substrate in the structural member.

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