阅读说明：本技术 树脂-金属复合体和制备方法，以及壳体 (Resin-metal composite body and production method, and case ) 是由 张云侠 宋文广 邓善全 陈梁 于 2019-08-22 设计创作，主要内容包括：本发明公开了树脂-金属复合体和制备方法,以及壳体。该方法包括：将所述金属基体置于碱性电解液中进行阳极氧化处理,所述碱性电解液中氢氧根的浓度为170-210g/L,以便在所述金属基体的至少部分表面形成多孔氧化膜；以及在所述金属基体上具有所述多孔氧化膜的位置处注塑树脂,以形成所述树脂-金属复合体。总的来说,该方法可利用环境友好的试剂对金属基体进行处理,且最终获得的树脂-金属复合体的树脂以及金属之间的结合强度较强。(The invention discloses a resin-metal composite and a preparation method thereof, and a shell. The method comprises the following steps: placing the metal matrix in alkaline electrolyte to carry out anodic oxidation treatment, wherein the concentration of hydroxyl in the alkaline electrolyte is 170-210g/L, so as to form a porous oxide film on at least part of the surface of the metal matrix; and injection molding a resin at a position having the porous oxide film on the metal substrate to form the resin-metal composite. In general, the method can treat the metal matrix with an environment-friendly agent, and the finally obtained resin-metal composite has strong bonding strength between the resin and the metal.)

1. A method of making a resin-metal composite comprising:

providing a metal matrix;

placing the metal matrix in alkaline electrolyte to carry out anodic oxidation treatment, wherein the concentration of hydroxyl in the alkaline electrolyte is 170-210g/L, so as to form a porous oxide film on at least part of the surface of the metal matrix; and

injecting a resin at a position having the porous oxide film on the metal substrate to form the resin-metal composite.

2. The method as claimed in claim 1, wherein the porous oxide film comprises pores with a pore size of 20-300nm, and the thickness of the porous oxide film is 100-500 nm.

3. The method of claim 1 or 2, wherein the alkaline electrolyte comprises a strong base,

the concentration of the sodium hydroxide in the alkaline electrolyte is 400-500g/L,

or the concentration of the potassium hydroxide in the alkaline electrolyte is 560-690 g/L.

4. The method according to claim 3, wherein the voltage of the anode during the anodic oxidation is controlled to be 5-15V.

5. The method as claimed in claim 3, wherein the current density of the anode during the anodic oxidation is controlled to be 0.2-0.8A/dm²。

6. The method according to claim 4 or 5, wherein the anodizing is performed at a temperature of 10 to 40 ℃ for 5 to 30 minutes.

7. The method of claim 1 or 2, further comprising at least one of:

before the anodic oxidation treatment, carrying out oil removal treatment and cleaning treatment on the metal matrix in advance;

and after the anodic oxidation treatment and before resin injection, performing second cleaning treatment and drying treatment on the metal substrate after the anodic oxidation treatment.

8. The method of claim 1, wherein the metal matrix comprises titanium and an alloy of titanium, the porous oxide film is formed at a sidewall of the metal matrix, and the resin injected is located at an end of the metal matrix;

or the metal matrix is provided with a slit penetrating through the metal matrix, the porous oxide film at least covers the side wall of the slit, and the injected resin is filled in the slit;

alternatively, the porous oxide film covers the entire surface of the metal base.

9. A resin-metal composite body characterized in that it is produced by the method according to any one of claims 1 to 8.

10. A housing, characterized in that it comprises the resin-metal composite body according to claim 9.

Technical Field

The invention relates to the field of materials, in particular to a resin-metal composite body and a preparation method thereof, and a shell.

Background

Metal and alloy plates are widely used for preparing shells of electronic equipment and the like due to good mechanical strength, corrosion resistance, fatigue resistance and heat dissipation performance. In metal and alloy plates, titanium and titanium alloy have wide application prospect in the fields of shell and inner member materials of electronic products (such as mobile phones, notebook computers, flat panels and the like) due to the advantages of light weight, high specific strength and the like, and the thermal stability and corrosion resistance far superior to those of aluminum alloy. For example, titanium and titanium alloys can achieve higher gloss after polishing than aluminum alloys, achieve gloss close to that of stainless steel, and have density lower than that of stainless steel and light weight. To solve the problem of shielding the signal by a housing made of metal (such as the aforementioned titanium and titanium alloy), it is usually necessary to open a slot in the metal housing and fill the slot with a non-conductive material to form an antenna slot. For example, metal and plastic are currently used in combination with integrated sheet materials to form the housing. For example, the metal substrate may be surface treated and then injection molded to form a plastic antenna seam.

However, the current resin-metal composites and methods of preparation, as well as housings, remain to be improved.

Disclosure of Invention

The present invention is based on the discovery and recognition by the inventors of the following facts and problems:

as described above, in order to prevent the all-metal case from shielding the signal, the case is generally formed of a resin-metal composite. To enhance the bond between the injection molded plastic and the metal substrate, the metal surface is typically first treated prior to injection molding. The surface treatment process for titanium and titanium alloy mainly comprises two types of treatment under acidic environment and treatment under alkaline environment. The acidity mainly uses hydrofluoric acid, hydrochloric acid and the like as main solutions to corrode the titanium alloy, so that holes are formed on the surface of the titanium alloy, and the plastic can enter the holes to enhance the binding force during molding, or a porous film is formed on the surface of the titanium alloy and the titanium alloy in an electrochemical mode by using the hydrofluoric acid as the main solution, so that the binding force between the titanium alloy and the plastic is enhanced. Although the method can improve the bonding strength of titanium and titanium alloy, the used solution often needs to be added with organic additives or halogen ions, so that the method has the disadvantages of great environmental pollution, high sewage treatment cost and unsuitability for large-scale production. In addition, hydrofluoric acid is too corrosive, has great harm to human bodies and is not beneficial to industrial production. Alkaline environment treatment is an electrochemical treatment mainly using an alkaline solution or the like as a main solution, and can alleviate the problem of environmental pollution, but the bonding strength of the composite formed by the conventional alkaline method is not large. Therefore, if an environmentally friendly and reliable preparation method with reliable bonding strength can be provided, the technical problems can be greatly alleviated or even solved.

In view of the above, in one aspect of the present invention, a method of preparing a resin-metal composite is provided. The method comprises the following steps: providing a metal matrix; placing the metal matrix in alkaline electrolyte to carry out anodic oxidation treatment, wherein the concentration of hydroxyl in the alkaline electrolyte is 170-210g/L, so as to form a porous oxide film on at least part of the surface of the metal matrix; and injection molding a resin at a position having the porous oxide film on the metal substrate to form the resin-metal composite. In general, the method can treat the metal matrix with an environment-friendly agent, and the finally obtained resin-metal composite has strong bonding strength between the resin and the metal.

In another aspect of the invention, the invention features a resin-metal composite. The resin-metal composite is obtained by the method described above. Thus, the resin-metal composite has all the features and advantages of the composite obtained by the method described above, and will not be described herein again. In general, the composite has at least one of the advantages of low production cost, environmental friendliness, strong bonding strength and the like.

In yet another aspect of the present invention, a housing is presented. The housing includes the resin-metal composite described above. The shell thus has all the features and advantages of the complex described above, which are not described in detail here. Generally, the shell has at least one of the advantages of low production cost, environment-friendly preparation process, long service life and the like.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 shows a schematic flow diagram of a method of making a resin-metal composite body according to one embodiment of the invention;

FIG. 2 shows a schematic flow diagram of a method of making a resin-metal composite body according to another embodiment of the invention;

FIG. 3 shows a scanning electron microscope photograph of an anodized metal substrate according to an embodiment of the invention;

fig. 4 shows a schematic structural view of a resin-metal composite body according to an embodiment of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In one aspect of the invention, a method of making a resin-metal composite is presented. Specifically, the present invention forms a porous oxide film composed of pores with a pore diameter of 20 to 300nm on the surface of a substrate by a single anodic oxidation treatment by controlling the concentration of hydroxyl in an alkaline electrolyte and the conditions of the anodic oxidation treatment. After the metal matrix with the structure is subjected to injection molding in the mold, the metal matrix and the plastic can achieve high bonding strength which can reach more than 30MPa, and further a complex structure can be formed on the metal matrix through injection molding, and various materials (such as PPS, PBT, PA and the like) can form a resin-metal complex with the metal matrix through injection molding. In general, the method has at least one of the advantages of simple process conditions, strong operability, no environmental pollution in the treatment process and the like.

The steps of the method are described in detail below with reference to specific examples of the present application. Referring to fig. 1, the method may include:

s100: providing a metal matrix

According to an embodiment of the invention, in this step, a metal matrix is first provided. According to the embodiment of the present invention, the specific type of the metal base is not particularly limited as long as an anodized film made of a metal oxide can be formed by the process treatment of alkaline anodization described in the present invention. For example, titanium and alloys of titanium are possible. The specific shape of the metal base is not particularly limited, and may be, for example, a flat plate, a plate having a curved surface, or a tubular material.

To further improve the efficiency of the subsequent processing, prior to performing the subsequent processing, for example, prior to performing the anodic oxidation processing, referring to fig. 2, the method may further include:

s10: subjecting the metal substrate to degreasing treatment and first cleaning treatment

According to an embodiment of the present invention, in this step, the degreasing treatment and the first cleaning treatment may be sequentially performed on the metal base. Specifically, the metal substrate may be degreased in a cleaning solution to remove oil stains on the surface of the metal substrate. And finally, performing flowing water washing treatment to remove the residual cleaning solution on the surface of the metal matrix.

According to some embodiments of the present application, before the oil removing treatment, the metal substrate may be first subjected to treatments including, but not limited to, physical grinding, polishing, and the like to remove hard impurities and relatively protruding bumps on the surface of the metal substrate, and then subsequent oil removing treatment and cleaning treatment may be utilized to remove polishing solution, polishing powder, oil removing agent, and the like remaining in the previous steps of polishing, grinding, and oil removing treatment, so as to make the surface of the metal substrate have a clean and flat surface, thereby on one hand, the efficiency of subsequent anodic oxidation treatment may be improved, and on the other hand, it may also be prevented that corrosion rates at different positions are different due to uneven or insufficient cleaning of the surface of the metal substrate, and further the subsequent combination with the resin material is affected.

S200: putting the metal matrix into alkaline electrolyte for anodic oxidation treatment

According to an embodiment of the invention, in this step, the metal substrate is subjected to an anodic oxidation treatment. Specifically, in this step, an alkaline electrolyte is used, the metal base is used as an anode, and an anodic oxidation treatment is performed in the alkaline electrolyte having a relatively low voltage and a relatively high concentration, so that a porous oxide film is formed on at least a part of the surface of the metal base. The porous oxide film can improve the binding force between the injection molding numerical value and the metal matrix in the subsequent step, thereby obtaining the resin-metal complex with higher binding strength.

Specifically, the porous oxide film formed in this step may include pores having a pore diameter of 20 to 300nm, and the pores having a pore diameter in the above range may be stacked and nested with each other to form the porous oxide film. The thickness of the porous oxide film may be 100-500 nm. Therefore, the porous oxide film can be utilized to form a complex structure film layer on the surface of the metal matrix, and the inventor finds that the structure is beneficial to improving the binding force between subsequently formed injection molding resin and the metal matrix through a large amount of experiments: the porous oxide film has a proper pore size range, most resin materials can be easily filled in pores of the porous oxide film in the injection molding process, the actual bonding area between the resin materials and the metal matrix is not obviously improved due to the fact that the filling efficiency is reduced due to too small pore size, or the resin materials are easy to fall off and peel off from the metal matrix in the subsequent use process due to too large pore size. In addition, the porous oxide film formed by the small holes with the pore diameter range of 20-300 nanometers can form a more complex porous nested structure, and the pore diameter is suitable for the resin to be fully filled into the porous film in the injection molding process, so that the reliable connection between the resin and the metal matrix can be ensured.

According to an embodiment of the present invention, the metal substrate is titanium or a titanium alloy, and in this step, the metal substrate may be used as an anode to perform an anodic oxidation treatment in an alkaline solution. The anodic oxidation treatment can be carried out at a voltage of 5-15V or at a voltage of 0.2-0.8A/dm²At a current density of (a). As will be appreciated by those skilled in the art, the anodization process is a process in which a metal substrate is used as an anode of an electrolytic cell and is subjected to an oxidation reaction in an alkaline electrolyte. The anodization process may be controlled by controlling the voltage applied to the anode (i.e., the metal substrate) or, when selectedUnder the premise of the inert cathode, the current density of the anode in the anodic oxidation process can be controlled according to the specific composition and size of the inert cathode (such as a Pt or Au electrode). Therefore, the anodization process may satisfy both the voltage and current density conditions, or one of the voltage and current density conditions. Thus, pores (with a pore diameter of 20-300nm) with a proper pore diameter range can be formed on the surface of the metal substrate, and the pores are nested with each other to form a porous oxide film with a thickness of 100-500 nm. The porous oxide film can improve the binding force between resin formed by subsequent injection molding treatment and a metal matrix. Specifically, the prepared alkaline electrolyte may be a solution of a strong base, and may include, for example, an alkaline solution mainly containing potassium hydroxide or sodium hydroxide. According to some embodiments of the present application, the concentration of hydroxide in the alkaline electrolyte may be 170-210 g/L. For example, it may be 180g/L, 185g/L, 190g/L, 195g/L, 200g/L, etc. In order to ensure that the electrolyte can maintain a stable pH during the anodization process, a buffer component, such as, but not limited to, a buffer agent such as EDTA, can be added to the alkaline electrolyte as appropriate. When the inorganic base in the alkaline electrolyte is sodium hydroxide, the concentration of the sodium hydroxide can be 400-500 g/L. For example, the concentration can be 410-480g/L, such as 410g/L, 420g/L, 430g/L, 440g/L, 450g/L, 460g/L, etc. When the inorganic base in the alkaline electrolyte is potassium hydroxide, the concentration of potassium hydroxide can be 560-690g/L, such as 580-660g/L, e.g., 590g/L, 600g/L, 610g/L, 620g/L, 630g/L, 650g/L, etc. In order to further improve the efficiency of the anodic oxidation treatment, the alkaline electrolyte may also be subjected to a heating treatment in this step. For example, the solution temperature of the alkaline electrolyte may be set to 10 to 40 ℃. Under such conditions, the time for the anodic oxidation may be 5 to 30min, whereby the porous oxide film can be formed relatively easily.

The alkaline electrolyte adopted by the invention does not contain inorganic reagents which are harmful to the environment, for example, the alkaline electrolyte does not contain reagents (such as hydrofluoric acid) containing halogen ions, and does not contain substances which have larger toxicity to human bodies or can generate larger toxicity to human bodies, so that on one hand, a preparation method which is more friendly to the environment can be provided, on the other hand, reagents with overlarge toxic and side effects can be prevented from being introduced in the preparation process, and the risk of safety accidents of workers in the production process is reduced.

According to an embodiment of the present invention, referring to fig. 2, after the anodizing treatment and before the resin is injection-molded, the method may further include:

s20: performing a second cleaning process and a drying process on the anodized metal substrate

According to the embodiment of the present invention, in this step, the metal substrate on which the porous oxide film is formed through the anodic oxidation treatment is subjected to the second cleaning treatment and the baking treatment. Similarly, the second cleaning process may be performed with deionized water for removing the porous oxide film and the alkaline electrolyte remaining on the surface of the metal substrate. For example, the second washing treatment may be a water washing treatment. Subsequently, the metal substrate subjected to the third cleaning process may be subjected to a baking process, for example, may be baked at 60 ℃, and more specifically, the metal substrate may be placed in an oven to be baked.

It should be noted that, in the present invention, the first cleaning process, the second cleaning process, and the like are only for distinguishing between a plurality of cleaning process operations, and cannot be understood as distinguishing between the importance of the two cleaning processes and the specific operations. The first cleaning process and the second cleaning process may be performed in the same or different manner, as long as impurities or residual reagents remaining on the surface of the metal substrate in the previous process step can be cleaned. For example, both cleaning processes may be performed using deionized water.

S300: injection molding a resin at a position having the porous oxide film on the metal substrate

According to an embodiment of the present invention, a resin is injection-molded at a position having a porous oxide film on a metal substrate in this step to form the resin-metal composite. According to the embodiment of the present invention, the specific chemical composition of the resin material used for injection molding in this step is not particularly limited, and PPS, PBT, PA, etc. may be used for injection molding.

Specifically, for example, a plastic part having a certain shape can be formed by injection molding a plastic material (resin) at a specific position of a metal base using an injection mold, thereby obtaining a resin-metal composite.

According to an embodiment of the present invention, the position at which the injection molding is performed in this step is a position at which a porous oxide film is formed on the metal substrate. Therefore, the bonding force between the plastic part and the metal substrate can be improved by utilizing the porous structure of the porous oxide film. Specifically, the metal base may be a bar-shaped base, the porous oxide film may be formed at a sidewall of the metal base, and the injection-molded resin may be located at an end of the metal base. The formed resin-metal composite may have a structure as shown in fig. 4. Alternatively, the metal base may have a slit formed therethrough, the porous oxide film may cover at least a side wall of the slit, and the slit may be filled with an injection-molded resin. Thus, the resin-metal composite can be used as a shell of an electronic device, and the resin filled in the slit is used as an antenna slot of the shell, so that the metal shell is prevented from shielding communication signals. According to some embodiments of the present invention, the porous oxide film may cover the entire surface of the metal substrate, and the injection-molded resin may cover the entire surface of the metal substrate. For example, according to some embodiments of the present invention, the composite body formed by the above method may be a flat plate, a plate having a curved surface, or a tubular composite body.

In general, a method of preparing a resin-metal composite body according to an embodiment of the present invention has at least one of the following advantages:

1. alkaline liquid (such as sodium hydroxide, potassium hydroxide and the like) is used as a main body solution for anodic oxidation, and the components are nontoxic and environment-friendly.

2. The concentration of the alkali solution for anodic oxidation and the electrolysis condition are controlled, a porous oxide film structure with moderate aperture and thickness can be obtained, the bonding strength of the resin and the metal matrix can reach more than 30MPa, the bonding is stable, and the environmental test result is better.

3. The resin and the metal matrix have high bonding strength, can be used for forming complex structures, has a plurality of plastic choices, is suitable for various models of titanium and titanium alloy, and has wide application.

In yet another aspect of the present invention, a resin-metal composite is provided. The resin-metal composite comprises a metal substrate and an injection molding part, wherein at least part of the surface of the metal substrate is provided with a porous oxide film, the porous oxide film comprises small holes with the hole diameter of 20-300nm, and the thickness of the porous oxide film can be 100-500 nm. The injection part is formed of resin, and the injection part is located where the metal substrate has a porous oxide film. Therefore, the injection part can be filled into the porous oxide film, and the bonding force between the injection part and the metal substrate can be improved by utilizing the porous oxide film. The porous oxide film can enhance the combination between the injection molding part and the metal matrix, and the combination strength of the resin and the metal matrix can reach more than 30 MPa.

The resin-metal composite may be prepared using the method described above. Thus, the resin-metal composite can have all the features and advantages of the plate obtained by the method described above, and will not be described herein again. For example, the resin-metal composite may have an injection-molded part formed by injection-molding plastic, and a metal base. In some examples of the invention, the structure of the resin-metal composite may be as shown in fig. 4.

It is to be noted that the specific shape of the resin-metal composite body, and the specific shape and position of the injection molded part are not particularly limited as long as the injection molded part is formed at a position on the metal base body on the composite body having the above-mentioned porous oxide film. For example, the metal base may be a bar-shaped base, the porous oxide film may be formed at a sidewall of the metal base, and the injection molded part may be located at an end of the metal base. Alternatively, the metal base may have a slit formed therethrough, and the injection molded part may be filled in the slit. Alternatively, the porous oxide film may cover the entire surface of the metal substrate, and the injection molded part may cover the entire surface of the metal substrate. The composite may be a flat plate, a plate having a curved surface, or a tubular composite.

In yet another aspect of the present invention, a housing is presented. The housing includes the resin-metal composite described above. Thus, the housing may have all of the features and advantages of the previously described sheet material, which are not described in detail herein. For example, the housing may be a housing of an electronic device, wherein the metal base portion of the plate may serve as a base of the housing, and the injection-molded portion may serve as an antenna slot or an antenna seam of the housing, so as to prevent the metal base from shielding communication signals.

The present invention is illustrated below by way of specific examples, which are intended to be illustrative only and not to limit the scope of the present invention in any way, and reagents and materials used therein are commercially available, unless otherwise specified, and conditions or steps thereof are not specifically described.

Example 1

Preparing NaOH aqueous solution with the concentration of 480g/L, using a PP groove to dissolve and stir a large amount of heat, standing for 2 hours, measuring the temperature by a thermometer at 26 ℃ for standby, grinding the surface of a TA1(3 x 12 x 40mm) metal matrix by a grinder, then performing oil removal and water washing, putting the TA1 metal matrix into the prepared NaOH aqueous solution PP groove, performing constant voltage of 8V by a direct current power supply at room temperature (25-35 ℃), and baking after electrifying for 20 minutes. The scanning electron micrograph of the formed porous oxide film is shown in FIG. 3. And then placing the molded product into an injection molding machine for injection molding of PBT plastic, and testing the drawing force on a universal testing machine after molding, wherein the test results are shown in Table 1.

Example 2

Preparing NaOH aqueous solution with the concentration of 480g/L, using a PP groove to dissolve and stir a large amount of heat, standing for 2 hours, measuring the temperature by a thermometer at 26 ℃ for standby, grinding the surface of a TA2(3 multiplied by 12 multiplied by 40mm) metal substrate by a grinding machine, then removing oil and washing, putting the TA2 metal substrate into the prepared NaOH aqueous solution PP groove, keeping the constant voltage of 10V by a direct current power supply at room temperature (25-35 ℃), electrifying for 20 minutes, then baking, putting into an injection molding machine for injection molding of PBT plastic, testing the drawing force on the universal testing machine after molding, and testing results are shown in Table 1.

Embodiment 3

Preparing NaOH aqueous solution with the concentration of 480g/L, dissolving and stirring a large amount of heat by using a PP (polypropylene) tank, standing for 2H, measuring the temperature by using a thermometer at 26 ℃ for standby, grinding the surface of a TC4(3 multiplied by 12 multiplied by 40mm) sample strip by using a grinding machine, then carrying out oil removal and water washing, putting the TC4 sample strip into the prepared NaOH aqueous solution PP tank, keeping the constant voltage of 10V by using a direct-current power supply at room temperature (25-35 ℃), electrifying for 20min, then baking, putting into an injection molding machine for injection molding PBT plastic, testing the drawing force on a universal testing machine after molding, and testing results are shown in Table 1. After the environmental test is synchronously performed, the bonding strength is tested, and the bonding strength is not reduced, see the environmental test part in Table 2.

Example 4

The other steps are the same as the example 3, except that NaOH aqueous solution is prepared, the concentration of the NaOH aqueous solution is 450g/L, alkaline electrolyte is used, and the anodic oxidation treatment is carried out under the conditions that the direct current power supply has constant voltage of 6V and the electrification is carried out for 20 min. The drawing force was measured on a universal tester after molding, and the test results are shown in table 1.

Example 5

The other steps are the same as the example 3, except that NaOH aqueous solution is prepared, the concentration of the NaOH aqueous solution is 450g/L, alkaline electrolyte is used, and the anodic oxidation treatment is carried out under the conditions that the direct current power supply has constant voltage of 8V and the electrification is carried out for 20 min. The drawing force was measured on a universal tester after molding, and the test results are shown in table 1.

Example 6

The other steps are the same as the example 3, except that NaOH aqueous solution is prepared, the concentration of the NaOH aqueous solution is 450g/L, alkaline electrolyte is used, and the anodic oxidation treatment is carried out under the conditions that the direct current power supply has constant voltage of 10V and the electrification is carried out for 20 min. The drawing force was measured on a universal tester after molding, and the test results are shown in table 1.

Example 7

The other steps are the same as the example 3, except that NaOH aqueous solution is prepared, the concentration of the NaOH aqueous solution is 420g/L, alkaline electrolyte is used, and the anodic oxidation treatment is carried out under the conditions that the direct-current power supply has constant voltage of 6V and the electrification is carried out for 20 min. The drawing force was measured on a universal tester after molding, and the test results are shown in table 1.

Example 8

The other steps are the same as the example 3, except that NaOH aqueous solution is prepared, the concentration of the NaOH aqueous solution is 420g/L, alkaline electrolyte is used, and the anodic oxidation treatment is carried out under the conditions that the direct current power supply has constant voltage of 8V and the electrification is carried out for 20 min. The drawing force was measured on a universal tester after molding, and the test results are shown in table 1.

Example 9

The other steps are the same as the example 3, except that NaOH aqueous solution is prepared, the concentration of the NaOH aqueous solution is 420g/L, alkaline electrolyte is used, and the anodic oxidation treatment is carried out under the conditions that the direct-current power supply has constant voltage of 10V and the electrification is carried out for 20 min. The drawing force was measured on a universal tester after molding, and the test results are shown in table 1.

Example 10

The other steps are the same as example 3, except that a KOH solution with a concentration of 590g/L is prepared as an alkaline electrolyte.

Example 11

The other steps are the same as example 3, except that a KOH solution with a concentration of 660g/L is prepared as an alkaline electrolyte.

Example 12

The other steps were the same as in example 5, except that a KOH solution having a concentration of 660g/L was prepared as an alkaline electrolyte.

Comparative example 1

Preparing a sulfuric acid aqueous solution (I) with the concentration of 100g/L, using a PP tank to dissolve and stir a large amount of heating and standing for 2H, measuring the temperature by a thermometer to be 26 ℃, completely dissolving for later use, preparing a NaOH aqueous solution (II) with the concentration of 200g/L, using the PP tank to dissolve and stir a large amount of heating and standing for 2H, measuring the temperature by a thermometer to be 26 ℃, completely dissolving for later use, grinding the surface of a TC4(3 multiplied by 12 multiplied by 40mm) metal substrate by a grinder, then carrying out oil removal washing, putting a TC4 metal substrate into the prepared sulfuric acid aqueous solution (I), taking a TC4 metal substrate as a cathode, keeping a direct current power supply constant voltage of 20V, washing after being electrified for 10min, putting the TC4 metal substrate into the prepared NaOH aqueous solution (II), taking a TC4 metal substrate as an anode, keeping the direct current power supply constant voltage of 20V, washing and drying after being electrified for 10min, putting into an injection molding PBT plastic, testing the pulling force, the test values are reported in table 1.

Comparative example 2

Preparing NaOH aqueous solution with the concentration of 280g/L, using a PP tank to dissolve and stir a large amount of heat, standing for 2H, measuring the temperature by a thermometer at 26 ℃ for standby, grinding the surface of a TC4(3 multiplied by 12 multiplied by 40mm) metal substrate by a grinding machine, then removing oil and washing, putting the TC4 metal substrate into the prepared NaOH aqueous solution PP tank, keeping the direct-current power supply at constant voltage of 10V, powering for 20min, then baking, putting into an injection molding machine for injection molding of PBT plastic, testing the drawing force value on the universal testing machine after molding, and recording the drawing force value in Table 1.

Comparative example 3

Preparing NaOH aqueous solution with the concentration of 600g/L, using a PP tank to dissolve and stir a large amount of heat, standing for 2H, measuring the temperature by a thermometer at 26 ℃ for standby, grinding the surface of a TC4(3 multiplied by 12 multiplied by 40mm) metal substrate by a grinding machine, then removing oil and washing, putting the TC4 metal substrate into the prepared NaOH aqueous solution PP tank, keeping the direct-current power supply at constant voltage of 10V, powering for 20min, then baking, putting into an injection molding machine for injection molding of PBT plastic, testing the drawing force value on the universal testing machine after molding, and recording the drawing force value in Table 1.

Comparative example 4

Preparing NaOH aqueous solution with the concentration of 480g/L, using a PP tank to dissolve and stir a large amount of heat, standing for 2H, measuring the temperature by a thermometer at 26 ℃ for standby, grinding the surface of a TC4(3 multiplied by 12 multiplied by 40mm) metal substrate by a grinding machine, then removing oil and washing, putting the TC4 metal substrate into the prepared NaOH aqueous solution PP tank, keeping the direct-current power supply at a constant voltage of 18V, electrifying for 20min, then baking, putting into an injection molding machine for injection molding of PBT plastic, testing the drawing force value on the universal testing machine after molding, and recording the drawing force value in Table 1.

Comparative example 5

The other parameters are the same as the embodiment 3, except that saturated aqueous solution of sodium carbonate is prepared as alkaline electrolyte, a porous oxide film can not be formed on the surface of the metal matrix after anodic oxidation treatment, and the test tensile force is less than 20MPa after plastic injection.

The test equipment for the drawing test is a universal tester, the tensile speed is 5mm/min, and the unit MPa (acting on the unit area (m)²) Force (N) above). The drawing strength of the example using KOH solution as the alkaline electrolyte was similar to that of the example using sodium hydroxide solution.

TABLE 1

Serial number	Tensile Strength/MPa
		Example 1	31.63
Example 2	33.26
		Embodiment 3	33.84
Example 4	32.25
		Example 5	34.84
Example 6	32.63
		Example 7	31.98
Example 8	32.54
		Example 9	33.13
Embodiment 10	32.05
		Example 11	32.89
Example 12	32.17
		Comparative example 1	28.96
Comparative example 2	28.93
		Comparative example 3	26.76
Comparative example 4	24.01

As is clear from the test results in Table 1, all the examples of the present application have a pull strength of 30MPa or more.

Table 2: environmental testing

As can be seen from the test results in table 2, the environmental tests of the samples obtained in example 3 all passed, and the pull-out strength did not significantly decrease after the reliability test.

In the description of the present invention, the terms "upper", "lower", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of describing the present invention but do not require that the present invention must be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description herein, references to the description of "one embodiment," "another embodiment," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction. In addition, it should be noted that the terms "first" and "second" in this specification are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.