An electrochemical etching method of a metal composite

Abstract

This application provides an electrochemical etching method for a metal composite, comprising a first metal part and a second metal part interconnected. The electrochemical etching method includes: anodizing the metal composite to form a first oxide film on the surface of the first metal part and a second oxide film on the surface of the second metal part; placing the anodized metal composite in a sealing solution to seal the first oxide film; placing the metal composite with the first oxide film sealed in an etching solution and applying ultrasonic waves, using the metal composite as the anode, to perform electrochemical etching to remove the second oxide film and form micropores on the surface of the second metal part; wherein the etching solution comprises: water, a water-miscible organic solvent, an acid, and a soluble chloride. The method provided in this application solves the problems of complex pretreatment, difficulty in corrosion, and difficulty in protecting aluminum alloys in micropore etching of metal composites.

Description

Technical Field

[0001] This application belongs to the field of electrochemical etching technology, and particularly relates to an electrochemical etching method for metal composites. Background Technology

[0002] Titanium alloys ensure high product strength. Titanium-aluminum composites use titanium alloy on the outer surface to guarantee high strength, and aluminum alloy on the inner surface to reduce machining costs. The composite material as a whole reduces weight and facilitates metal recycling. The use of titanium-aluminum composites for electronic product casings is a growing trend. In electronic product applications, to meet drop test requirements and waterproof performance, a tight bond between the metal and plastic is necessary; therefore, microporous etching is required on the titanium-aluminum composite material.

[0003] However, when performing micro-hole etching on titanium-aluminum composite materials, due to the significant differences in the physicochemical properties and potential of the two metals, the titanium side often fails to form a hole while the aluminum side has already been corroded. Therefore, there is an urgent need for an etching method that can form a hole on the titanium side of titanium-aluminum composite materials. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide an electrochemical etching method for metal composites, which can effectively form micropores on the titanium alloy surface of titanium-aluminum composites.

[0005] This application provides an electrochemical etching method for a metal composite, the metal composite comprising a first metal part and a second metal part connected to each other, the electrochemical etching method comprising:

[0006] The metal composite is subjected to anodizing treatment to form a first oxide film on the surface of the first metal part and a second oxide film on the surface of the second metal part;

[0007] The anodized metal composite is placed in a sealing solution for sealing treatment to seal the first oxide film.

[0008] The metal composite, after being sealed with the first oxide film, is placed in an etching solution, and ultrasonic waves are applied. Using the metal composite as the anode, electrochemical etching is performed to remove the second oxide film and form micropores on the surface of the second metal component.

[0009] The etching solution comprises:

[0010] Water, water-miscible organic solvents, acids, and soluble chlorides.

[0011] Furthermore, the water-miscible organic solvent is selected from polyols.

[0012] Furthermore, the material of the first metal part is selected from at least one of aluminum and aluminum alloys;

[0013] The material of the second metal part is selected from at least one of titanium, titanium alloy and stainless steel.

[0014] Furthermore, the voltage range for the anodizing treatment is 6V to 15V; the reagent for the anodizing treatment includes sulfuric acid.

[0015] Furthermore, the thickness of the first oxide film ranges from 3 μm to 12 μm; the thickness of the second oxide film ranges from 0.5 μm to 2 μm.

[0016] Furthermore, the sealing solution includes nickel acetate.

[0017] Furthermore, the voltage range of the electrochemical etching is 30V to 70V; the current density range of the electrochemical etching is 1A / dm³. 2 ~5A / dm 2 The electrochemical etching time range is 10 min to 30 min.

[0018] Furthermore, in the step of applying ultrasound, the frequency range of the ultrasound is 40kHz to 120kHz; and the time range of applying the ultrasound is 10min to 30min.

[0019] Furthermore, the step of applying ultrasound includes:

[0020] An ultrasonic wave is applied to the metal composite with a first power and processed for a first preset time.

[0021] An ultrasonic wave is applied at a second power to the metal composite material that has been treated with the first power ultrasonic wave, and the treatment lasts for a second preset time.

[0022] Ultrasonic waves of a third power are applied to the metal composite material after it has been treated with ultrasonic waves of the second power, and the treatment lasts for a third preset time; wherein,

[0023] The first power is greater than the second power, and the second power is greater than the third power.

[0024] Furthermore, the pore size of the micropores ranges from 20 μm to 200 μm.

[0025] This application focuses on the preparation of microporous structures in titanium-aluminum die-casting composite materials. An organic system containing corrosive components is used as the electrolyte, and high-voltage, low-current electrochemical etching is performed in a solution environment with ultrasonic waves of a certain frequency. This process does not damage the aluminum alloy part of the titanium-aluminum composite material and can form a microporous structure in the titanium alloy part of the titanium-aluminum composite material that can be injection molded.

[0026] Furthermore, in this application, anodic oxidation is performed at low voltage. The oxide film thickness formed on the titanium alloy portion of the titanium-aluminum composite material is less than that on the aluminum alloy portion, making it more susceptible to corrosion. The titanium alloy portion can only form an oxide film of less than 2 μm. As the reaction proceeds, while the oxide film on the aluminum alloy portion grows normally, the oxide film on the titanium alloy portion remains in a state of equilibrium between dissolution and growth. The thickness of the oxide film on the titanium alloy portion does not increase, but with further dissolution and growth, the oxide film on the titanium alloy portion has more defects and is more easily corroded. Additionally, the use of nickel acetate during the sealing process allows for the co-precipitation of nickel hydroxide and aluminum hydroxide, accelerating the sealing process. When the aluminum alloy portion of the titanium-aluminum composite material is completely sealed, the titanium alloy portion is not completely sealed, allowing the etching solution to more easily penetrate the oxide film formed on the titanium alloy portion. After the aluminum alloy portion is completely sealed, its insulation is better, and the current concentrates on the titanium alloy side, accelerating the corrosion of the titanium alloy. Therefore, the method provided in this application allows for the sealing of the aluminum alloy portion while the titanium alloy portion is not completely sealed, forming micropores on the titanium alloy surface during subsequent electrochemical etching.

[0027] The electrochemical etching method for metal composites provided in this application solves the problem that titanium alloys are difficult to etch micropores in the micropore etching of titanium-aluminum composite materials in the prior art, and can be extended to various titanium alloy products or new titanium-aluminum composite material products. Attached Figure Description

[0028] Figure 1 This is a flowchart of the electrochemical etching method in an embodiment of this application;

[0029] Figure 2 This is a 100x optical microscope image of the product prepared by the specific method in the embodiments of this application;

[0030] Figure 3 This is a 200x optical microscope image of the product prepared by the specific method in the embodiments of this application;

[0031] Figure 4 An optical microscope image of the product obtained in Comparative Example 1 of this application;

[0032] Figure 5 An optical microscope image of the product obtained in Embodiment 2 of this application;

[0033] Figure 6 An optical microscope image of the product obtained in Comparative Example 2 of this application;

[0034] Figure 7 An optical microscope image of the product obtained in Embodiment 5 of this application;

[0035] Figure 8 An optical microscope image of the product obtained in Comparative Example 6 of this application;

[0036] Figure 9 An optical microscope image of the product obtained in Embodiment 8 of this application;

[0037] Figure 10 An optical microscope image of the product obtained in Embodiment 7 of this application;

[0038] Figure 11 An optical microscope image of the product obtained in Comparative Example 9 of this application;

[0039] Figure 12 An optical microscope image of the product obtained in Embodiment 10 of this application;

[0040] Figure 13 An optical microscope image of the product obtained in Embodiment 11 of this application;

[0041] Figure 14 This is an optical microscope image of the product obtained in Embodiment 13 of this application. Detailed Implementation

[0042] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0043] like Figure 1 As shown, in some embodiments, this application provides an electrochemical etching method for a metal composite, the metal composite including a first metal part and a second metal part connected to each other, the electrochemical etching method including the following steps:

[0044] S1: The metal composite is anodized to form a first oxide film on the surface of the first metal part and a second oxide film on the surface of the second metal part;

[0045] Thus, an oxide film can be formed on both the surface of the first metal part and the surface of the second metal part. In some embodiments, step S1 is performed followed by step S2, which is described below:

[0046] S2: The anodized metal composite is placed in a sealing solution for sealing treatment to seal the first oxide film;

[0047] Thus, by sealing the pores, the properties of the first oxide film can be made more stable, and the first oxide film can better protect the first metal in the first metal part from corrosion. In some embodiments, step S2 is performed before step S3, and step S3 is described below:

[0048] S3: The metal composite after the first oxide film is sealed is placed in the etching solution, and ultrasonic waves are applied. Electrochemical etching is performed with the metal composite as the anode to remove the second oxide film and form micropores on the surface of the second metal part. The etching solution includes water, water-miscible organic solvent, acid and soluble chloride.

[0049] Thus, the first metal part is protected from the corrosion of the etching solution by the first oxide film after sealing, while the second oxide film on the surface of the second metal part is easily corroded by the etching solution because it is not sealed. Combined with ultrasonic treatment, the second oxide film is removed, so that the metal surface of the second metal part comes into contact with the etching solution to form micropores on the surface of the second metal part.

[0050] In some embodiments, the material of the first metal component may be selected from at least one of aluminum and aluminum alloys, and may further be an aluminum alloy, such as a 6-series aluminum alloy, specifically a 6013 aluminum alloy.

[0051] In some embodiments, the material of the second metal component may be selected from at least one of titanium, titanium alloy and stainless steel, and may further be a titanium alloy, such as TC4 titanium alloy.

[0052] In some embodiments, the temperature range for the anodic oxidation treatment can be 10°C to 30°C, more specifically 15°C to 25°C, and even more specifically 20°C; the voltage range can be 6V to 15V, more specifically 8V to 12V, and even more specifically 10V; the treatment time range can be 45min to 90min, more specifically 50min to 80min, and even more specifically 60min to 70min; the reagent may include sulfuric acid; the concentration range of the reagent can be 180g / L to 220g / L, more specifically 190g / L to 210g / L, and even more specifically 200g / L. This application allows for the acquisition of oxide films of different thicknesses by adjusting the process parameters during the anodic oxidation treatment.

[0053] In some embodiments, the thickness of the first oxide film can range from 3 μm to 12 μm, further from 5 μm to 10 μm, and even further from 6 μm to 8 μm.

[0054] In some embodiments, the thickness of the second oxide film can range from 0.5 μm to 2 μm, and more specifically from 1 μm to 1.5 μm.

[0055] In some embodiments, the metal composite can be a titanium-aluminum composite material, wherein the first metal part is composed of titanium alloy material and the second metal part is composed of aluminum alloy material. In this application, anodizing is performed under low voltage. The oxide film thickness formed by the titanium alloy portion in the titanium-aluminum composite material is less than that formed by the aluminum alloy portion, making it more susceptible to corrosion. The titanium alloy portion can only form an oxide film of less than 2 μm. As the reaction proceeds, while the oxide film formed by the aluminum alloy portion grows normally, the oxide film formed by the titanium alloy portion is constantly in a state of dissolution and growth equilibrium. The thickness of the oxide film formed by the titanium alloy portion does not increase, but with the progress of dissolution and growth, the oxide film formed by the titanium alloy portion has more defects and is more susceptible to corrosion.

[0056] In some embodiments, the sealing solution may include nickel acetate, and more particularly, a nickel acetate solution. In some embodiments, the concentration range of the sealing solution may be 5 g / L to 15 g / L, more particularly 8 g / L to 12 g / L, and even more particularly 10 g / L.

[0057] In some embodiments, nickel acetate is used during the sealing process to achieve co-precipitation of nickel hydroxide and aluminum hydroxide, which accelerates the sealing process. When the aluminum alloy part of the metal composite is completely sealed, the titanium alloy part is not completely sealed, and the etching solution can more easily enter the oxide film formed on the titanium alloy part. After the aluminum alloy part is completely sealed, the insulation is better, and the current is concentrated on the titanium alloy side, which accelerates the corrosion of the titanium alloy.

[0058] In some embodiments, the temperature range for the sealing process can be 90°C to 100°C, further 93°C to 97°C, and even further 95°C; the time range can be 15 min to 25 min, and even further 20 min.

[0059] In some embodiments, the process may further include:

[0060] The metal composite parts are degreased, alkali-etched, and have their black coating removed.

[0061] This application does not impose any special restrictions on the degreasing reagent; any degreasing reagent well-known in the art can be used and is commercially available. The concentration range of the degreasing reagent can be 50 g / L to 60 g / L, more specifically 53 g / L to 57 g / L, and even more specifically 55 g / L. In some embodiments, the degreasing temperature range can be 50°C to 60°C, more specifically 53°C to 57°C, and even more specifically 55°C. The degreasing time range can be 2 to 4 minutes, more specifically 3 minutes.

[0062] In some embodiments, grease and dirt on the surface of metal composite parts can be removed by degreasing.

[0063] In some embodiments, the reagent used for alkaline etching may be a sodium hydroxide solution. The concentration range of the sodium hydroxide solution may be 40 g / L to 60 g / L, more specifically 45 g / L to 55 g / L, and even more specifically 50 g / L.

[0064] In some embodiments, the temperature range for alkaline biting can be 45°C to 55°C, further can be 48°C to 52°C, and even further can be 50°C. The time range for alkaline biting can be 20s to 40s, further can be 25s to 35s, and even further can be 30s.

[0065] In some embodiments, the oxide film on the surface of metal composites, especially the oxide film on the aluminum alloy portion of titanium-aluminum composites, can be removed by alkaline etching.

[0066] In some embodiments, the reagent used for the black film stripping treatment can be a nitric acid solution. The concentration of the nitric acid solution can range from 20 g / L to 40 g / L, more specifically from 25 g / L to 35 g / L, and even more specifically from 30 g / L. The black film stripping treatment can be carried out at room temperature, more specifically from 20°C to 30°C, and even more specifically from 25°C. The time range for the black film stripping treatment can range from 0.5 min to 1.5 min, and even more specifically from 1 min.

[0067] In some embodiments, reaction deposits caused by alkaline etching on the surface of metal composites, especially reaction deposits on the aluminum alloy portion of titanium-aluminum composites, can be removed by peeling off the black film.

[0068] In some embodiments, the water may be pure water.

[0069] In some embodiments, the water-miscible organic solvent may be selected from polyols, and may further be ethylene glycol, propylene glycol, glycerol or butanediol, etc.

[0070] In some embodiments, the acid may be sulfuric acid.

[0071] In some embodiments, the soluble chloride may be potassium chloride or sodium chloride.

[0072] In some embodiments, the mass ratio of water, a water-miscible organic solvent, an acid, and a soluble chloride may be (15–25):(50–70):(10–20):(3–7), further may be (18–22):(55–65):(13–17):(4–6), and even further may be 20:60:15:5.

[0073] In some embodiments, during the step of applying ultrasound, the frequency range of the ultrasound can be 40kHz to 120kHz, and more specifically 80kHz to 100kHz. The duration of ultrasound application can be 10min to 30min, more specifically 15min to 25min, and even more specifically 20min. This application can use different ultrasound frequencies to obtain micropores of different sizes, and for nanoscale pores, MHz-level ultrasound can also be used.

[0074] In some embodiments, the step of applying ultrasound may include:

[0075] An ultrasonic wave is applied to a metal composite component at a first power for a first preset time.

[0076] Ultrasonic waves are applied at a second power to the metal composite material that has been treated with ultrasonic waves at a first power, and the treatment lasts for a second preset time.

[0077] Ultrasonic waves are applied at a third power to the metal composite material that has undergone ultrasonic treatment at a second power, and the treatment lasts for a third preset time; wherein,

[0078] The first power is greater than the second power, and the second power is greater than the third power.

[0079] In some embodiments, the frequency range of the ultrasonic waves applied with the first power can be 110kHz to 130kHz, further 115kHz to 125kHz, and even further 120kHz; the first preset time range can be 3min to 7min, further 4min to 6min, and even further 5min.

[0080] In some embodiments, the frequency range of the ultrasonic waves applied with the second power can be 70kHz to 90kHz, further 75kHz to 85kHz, and even further 90kHz; the second preset time range can be 3min to 7min, further 4min to 6min, and even further 5min.

[0081] In some embodiments, the frequency range of the ultrasonic waves applied with the third power can be 30kHz to 50kHz, further 35kHz to 45kHz, and even further 40kHz; the third preset time range can be 8min to 12min, and further 10min.

[0082] In some embodiments, the cathode used for electrochemical etching may be made of graphite or stainless steel.

[0083] In some embodiments, the voltage range for electrochemical etching can be 30V to 70V, more specifically 40V to 60V, and even more specifically 50V; the current density range can be 1A / dm². 2 ~5A / dm2 Further, it can be 2-4 A / dm 2 Furthermore, it can be 3A / dm 2 The time range can be 10 min to 30 min, further 15 min to 25 min, and even further 20 min; the temperature range can be 50℃ to 75℃, further 55℃ to 70℃, and even further 60℃ to 65℃. In some embodiments, the micropore diameter can be obtained by adjusting the voltage during the electrochemical etching process.

[0084] In some embodiments, electrochemical etching can be performed in an ultrasonic tank; the ultrasonic tank can be made of glass, stainless steel or titanium alloy.

[0085] In some embodiments, micropores are formed on the surface of the second metal part of the metal composite, namely the titanium alloy portion. The micropores are spike-like, meaning the pore walls have sharp structures that radially grow into the titanium alloy. This design increases the bonding force between the material and the titanium alloy portion when the material is subsequently formed into the micropores. Simultaneously, the diameter of the micropore opening near the surface of the titanium alloy portion is larger than the inner diameter, and the opening is funnel-shaped, making it easier for the material to enter the micropore and preventing the micropore from not being fully filled. It should be noted that the opening and interior of the micropore may be irregular shapes; therefore, the aforementioned opening diameter refers to the longest distance between any two points on the periphery of the opening. An imaginary plane parallel to the opening is defined, and the inner diameter refers to the longest distance between any two points on the boundary line between this imaginary plane and the inner wall of the hole. The pore diameter range can be 20μm to 200μm, further 50μm to 150μm, further 80μm to 120μm, and even further 100μm.

[0086] In some embodiments, the electrochemical etching process may further include:

[0087] The electrochemically etched metal composite parts are washed, dried, and injection molded.

[0088] In some embodiments, the water washing may be ultrasonic water washing; the ultrasonic frequency range during the water washing process may be 30kHz to 50kHz, further may be 35kHz to 45kHz, and even further may be 40kHz; the water washing temperature may be room temperature, further may be 20℃ to 30℃, and even further may be 25℃; the water washing time range may be 0.5min to 1.5min, and even further may be 1min.

[0089] In some embodiments, the drying method may be oven drying; the drying temperature range may be 60°C to 80°C, further may be 65°C to 75°C, and even further may be 70°C; the time range may be 5 min to 15 min, and further may be 10 min.

[0090] This application does not impose any special restrictions on the injection molding method. Any injection molding method well known to those skilled in the art can be used according to actual needs. Low-flow, high-strength polyurethane plastics can be used for injection molding.

[0091] The method provided in this application uses an organic system containing corrosive components as an electrolyte to perform high-voltage, low-current electrochemical etching in a solution environment with ultrasonic waves of a certain frequency. This method does not damage the aluminum alloy portion of the titanium-aluminum composite material and can form a micron-pore structure in the titanium alloy portion of the titanium-aluminum composite material that can be injection molded.

[0092] Examples and Comparative Examples

[0093] Microporous structures are prepared on a titanium-aluminum composite material, which includes a 6013 aluminum alloy layer and a TC4 titanium alloy layer disposed on the surface of the 6013 aluminum alloy layer, which is a die-cast composite material.

[0094] The process flow for preparing microporous structures is as follows:

[0095] Degreasing - water washing - alkaline etching - black film peeling - pre-anodization - pore sealing - ultrasonic-assisted electrochemical etching of titanium alloy surface - ultrasonic cleaning - drying - injection molding.

[0096] The specific method is as follows:

[0097] Degreasing: R105 degreasing agent (provided by Shenzhen Yongbao Chemical Co., Ltd.) was used to degrease the titanium-aluminum composite material surface for 3 minutes at 55℃ to remove grease and dirt.

[0098] Alkali etching: Use a 50g / L NaOH solution to perform alkaline etching at 50℃ for 30s to remove the natural oxide film on the aluminum alloy surface;

[0099] Black film removal: Use 30g / L nitric acid solution to remove the reaction deposits on the aluminum alloy surface for 1 minute at room temperature.

[0100] Pre-anodization: Anodization is performed using a 200 g / L sulfuric acid solution at 20°C and 8 V for 40 min to form an oxide film;

[0101] Sealing: The oxide film is sealed by treating it with a 10 g / L nickel acetate solution at 95°C for 20 min.

[0102] Ultrasonic electrochemical etching of titanium alloy: Electrochemical etching of titanium alloy is performed using an etching solution under ultrasonic assistance to form micron-sized pores on the surface of the titanium alloy. The etching solution consists of 20 wt% pure water, 15 wt% sulfuric acid, 60 wt% ethylene glycol, and 5 wt% potassium chloride. The anode is a titanium-aluminum composite material, and the cathode is graphite. The ultrasonic frequency is 40 kHz, the etching voltage is 30 V, and the etching time is 20 min. The obtained micropores have a pore size of 20 μm to 80 μm, a pore depth of 20 μm to 30 μm, and a pore density of 30%.

[0103] Ultrasonic water washing: Perform ultrasonic water washing at 40 kHz and room temperature for 1 minute;

[0104] Drying: Dry at 70℃ for 10 minutes;

[0105] Injection molding: Low-flow, high-strength polyurethane plastics are used for injection molding.

[0106] The cross-sectional optical microscope image of the product obtained after injection molding using the above method (taken with Keyence 6000) is shown below. Figure 2 and Figure 3 As shown, Figure 2 For 100x magnification, Figure 3 The image at 200x magnification shows that the titanium alloy side has micropores, while the aluminum alloy side does not.

[0107] The effect of anodizing process on the pore morphology of titanium alloy surface: The anodizing process parameters were adjusted according to the specific methods described above and the table below to obtain Examples 1-3 and Comparative Examples 1-4. The oxide film thickness was measured using a 3D optical profilometer manufactured by Sensofar. The corrosion condition of the aluminum alloy surface was determined by photographing the aluminum alloy surface using a Keyence 6000, and based on different corrosion conditions: 1) When the ratio of the corroded area to the total area is greater than 50%, it is defined as over-corrosion; 2) When the ratio of the corroded area to the total area is less than 50%, but greater than 5%, it is defined as general corrosion; 3) When the ratio of the corroded area to the total area is less than 5%, it is defined as weak corrosion. The pore diameter, pore depth, and pore density of the titanium alloy surface were measured using a Keyence 6000, and the specific test results are as follows:

[0108]

[0109] Figure 4 This is an optical microscope image of the product obtained in Comparative Example 1. Figure 5 This is an optical microscope image of the product obtained in Example 2. Figure 6 The image shows an optical microscope image of the product obtained in Comparative Example 2. It can be seen that the product obtained by the method in Comparative Example 1 has fewer micropores, the product obtained in Example 2 has a moderate number of micropores, and the product obtained in Comparative Example 2 has no micropores on its surface.

[0110] Anodizing forms an insulating oxide film on the surface of the aluminum alloy in the composite material, preventing current shielding of the titanium alloy during electrochemical treatment due to the higher chemical reactivity of aluminum. Therefore, excessively low voltage will result in poor protection of the aluminum alloy, interfering with current distribution and affecting titanium corrosion; conversely, excessively high voltage will cause oxide film to form on the titanium alloy surface as well, negatively impacting etching. Appropriate oxidation conditions must be selected. An insulating oxide layer is formed on the aluminum alloy surface to protect it during subsequent electrochemical etching. During the anodizing process, an oxide layer also forms on the titanium alloy surface. Different acid electrolytes will form different oxide films. Pure sulfuric acid electrolyte can form an oxide film of a certain thickness on the aluminum alloy surface at low pressure, but only a very thin oxide film on the titanium alloy, not hindering etching. Adding organic acids will act as corrosion inhibitors, reducing the film thickness on the aluminum alloy at the same voltage, thus affecting its protection. Simultaneously, the addition of organic acids will cause changes in the surface film of the titanium alloy, altering its morphology and making it more susceptible to surface corrosion.

[0111] The effect of ultrasound on micropore etching of titanium alloy: The ultrasonic process parameters were adjusted according to the table below using the specific methods described above, resulting in Examples 4-6 and Comparative Examples 5-7. The results were obtained by testing using the methods described above.

[0112]

[0113] Figure 7 This is an optical microscope image of the product obtained in Example 5. Figure 8 The image shows an optical microscope image of the product obtained in Comparative Example 6. The addition of ultrasound can improve etching efficiency, effectively increase hole depth, and reduce surface corrosion. The principle is as follows: In the initial etching stage, ultrasound, in conjunction with the etching agent, can effectively activate the titanium alloy surface and form uniform etching sites; during the etching process, ultrasound can effectively and quickly remove the reactants from the titanium alloy surface and rapidly migrate them out of the hole, which is beneficial for increasing hole depth and reducing lateral corrosion.

[0114] The effect of etching voltage on the etching of titanium alloy surfaces: The etching process parameters were adjusted according to the table below using the specific methods described above, resulting in Examples 7-9 and Comparative Examples 8-9. The results were obtained by testing using the methods described above.

[0115]

[0116] Figure 9 An optical microscope image of the product obtained in Example 8. Figure 10 This is an optical microscope image of the product obtained in Example 7. Figure 11The image shows an optical microscope image of the product obtained in Comparative Example 9. The etching voltage has a crucial impact on the formation of pores on the titanium alloy surface. If the voltage is too low, the surface oxide layer of the titanium alloy cannot be broken down under the action of the electric field, and the required microporous structure cannot be formed on the surface of the titanium alloy. If the voltage is too high, the surface corrosion and transverse corrosion of the titanium alloy surface will be greater than the longitudinal corrosion.

[0117] Different ultrasonic frequencies: The ultrasonic frequency parameters were adjusted according to the table below using the specific methods described above, resulting in Examples 10 to 12 and Comparative Example 10; the tests were performed using the methods described above, and the test results are as follows:

[0118]

[0119] Figure 12 An optical microscope image of the product obtained in Example 10. Figure 13 This is an optical microscope image of the product obtained in Example 11. Different frequencies of ultrasound have a greater impact on pore density. Higher frequencies generate more activation sites on the metal surface, resulting in a higher etched pore density. However, as the frequency increases, the etched pore depth decreases.

[0120] Ultrasonic combined effect: The ultrasonic method was adjusted according to the table below based on the specific methods described above, resulting in Example 13; the detection was performed according to the above methods, and the detection results are as follows:

[0121]

[0122] Figure 14 This is an optical microscope image of the product obtained in Example 13. By changing the ultrasonic frequency during the etching process, a high-density, deep-pore structure is formed on the surface of the titanium alloy. The principle is as follows: in the early stage of etching, the material surface is activated by high-frequency ultrasound to form a high-density reaction base point; then the frequency is gradually reduced, so that the reactants are easy to peel off and migrate from the material surface, allowing the pitting corrosion reaction to continue and increasing the depth of the pores.

[0123] This application focuses on the preparation of microporous structures in titanium-aluminum die-casting composite materials. An organic system containing corrosive components is used as the electrolyte, and high-voltage, low-current electrochemical etching is performed in a solution environment with ultrasonic waves of a certain frequency. This process does not damage the aluminum alloy part of the titanium-aluminum composite material and can form a microporous structure in the titanium alloy part of the titanium-aluminum composite material that can be injection molded.

[0124] While this application has been described and illustrated with reference to specific embodiments thereof, such description and illustration are not intended to limit the application. Those skilled in the art will readily understand that various changes may be made to suit particular circumstances, materials, compositions, substances, methods, or processes to the objectives, spirit, and scope of this application without departing from the true spirit and scope of the application as defined by the appended claims. All such modifications are intended to be within the scope of the appended claims. Although the methods disclosed herein have been described with reference to specific operations performed in a particular order, it should be understood that these operations may be combined, subdivided, or reordered to form equivalent methods without departing from the teachings of this application. Therefore, unless specifically indicated herein, the order and grouping of operations are not limitations of this application.

Claims

1. An electrochemical etching method for a metal composite, the metal composite comprising a first metal part and a second metal part connected to each other, the electrochemical etching method comprising: The metal composite is subjected to anodizing treatment to form a first oxide film on the surface of the first metal part and a second oxide film on the surface of the second metal part; The anodized metal composite is placed in a sealing solution for sealing treatment to seal the first oxide film. The metal composite, after being sealed with the first oxide film, is placed in an etching solution, and ultrasonic waves are applied. Using the metal composite as the anode, electrochemical etching is performed to remove the second oxide film and form micropores on the surface of the second metal component. The etching solution comprises: Water, a water-miscible organic solvent, an acid, and a soluble chloride, wherein the soluble chloride is potassium chloride or sodium chloride; The material of the first metal part is selected from at least one of aluminum and aluminum alloys; The material of the second metal component is selected from at least one of titanium and titanium alloys; The thickness of the first oxide film ranges from 3 μm to 12 μm; the thickness of the second oxide film ranges from 0.5 μm to 2 μm; and the voltage range of the electrochemical etching is 30 V to 70 V.

2. The electrochemical etching method according to claim 1, wherein, The water-miscible organic solvent is selected from polyols.

3. The electrochemical etching method of claim 1, wherein, The voltage range for the anodizing treatment is 6V to 15V; the reagent for the anodizing treatment includes sulfuric acid.

4. The electrochemical etching method of claim 1, wherein, The sealing solution includes nickel acetate.

5. The electrochemical etching method of claim 1, wherein, The current density range of the electrochemical etching is 1 A / dm. 2 ~5A / dm 2 The electrochemical etching time range is 10 min to 30 min.

6. The electrochemical etching method of claim 1, wherein, In the step of applying ultrasound, the frequency range of the ultrasound is 40kHz to 120kHz; and the time range of applying the ultrasound is 10min to 30min.

7. The electrochemical etching method of claim 1, wherein, The step of applying ultrasound includes: An ultrasonic wave is applied to the metal composite with a first power and processed for a first preset time. An ultrasonic wave is applied at a second power to the metal composite material that has been treated with the first power ultrasonic wave, and the treatment lasts for a second preset time. Ultrasonic waves are applied at a third power to the metal composite material that has been treated with ultrasonic waves at the second power, and the treatment lasts for a third preset time; wherein, The first power is greater than the second power, and the second power is greater than the third power.

8. The electrochemical etching method of claim 1, wherein, The pore size of the micropores ranges from 20μm to 200μm.

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