An electrolytic etching method for dissolving microstructure of an aluminum alloy

Abstract

The present disclosure provides an electrolytic corrosion method for dissolvable aluminum alloy microstructure, and relates to the technical field of metal material microstructure characterization. The method comprises: performing a pretreatment operation of polishing, polishing and cleaning on the dissolvable aluminum alloy; mixing anhydrous ethanol, fluoroboric acid, glycerol and perchloric acid to obtain an electrolyte for electrolytic corrosion; placing the pretreated dissolvable aluminum alloy as an anode and an inert electrode as a cathode in an electrolytic cell containing the electrolyte, and performing an electrolytic corrosion process; after the electrolytic corrosion process, taking out the dissolvable aluminum alloy, cleaning and blowing dry to obtain a dissolvable aluminum alloy that can be used for metallographic microscope observation of microstructure. The present disclosure can improve the corrosion effect of the dissolvable aluminum alloy microstructure.

Description

Technical Field

[0001] This disclosure relates to the field of characterization technology of metallic material microstructure, and more specifically, to an electrolytic corrosion method for dissolving aluminum alloy microstructure. Background Technology

[0002] Soluble aluminum alloys, due to their biodegradability and environmental friendliness, have broad application prospects in oil and gas development, medical devices, and temporary structural components. A key characteristic of these alloys is their spontaneous dissolution in aqueous solutions or water-containing systems, which poses a significant challenge to the corrosion characterization of their metallographic microstructure. Conventional corrosion methods struggle to precisely control the degree of corrosion and fail to clearly reveal microscopic features such as grains, grain boundaries, second phases, and internal defects, severely restricting the optimization of composition, process improvement, and performance research of soluble aluminum alloys.

[0003] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] The purpose of this disclosure is to provide an electrolytic corrosion method for dissolving aluminum alloy microstructures, thereby overcoming, at least to some extent, the problem of poor corrosion effect of dissolving aluminum alloy microstructures.

[0005] According to a first aspect of this disclosure, a method for electrolytic etching of a soluble aluminum alloy microstructure is provided, comprising: pretreatment operations of grinding, polishing and cleaning the soluble aluminum alloy; mixing anhydrous ethanol, fluoroboric acid, glycerol and perchloric acid to obtain an electrolyte for electrolytic etching; placing the pretreated soluble aluminum alloy as the anode and an inert electrode as the cathode in an electrolytic cell containing the electrolyte to perform an electrolytic etching process; after the electrolytic etching process, removing the soluble aluminum alloy, cleaning and drying it to obtain a soluble aluminum alloy that can be used for metallographic microscopy observation of microstructure.

[0006] Optionally, the pretreatment operations of grinding, polishing and cleaning the soluble aluminum alloy include: grinding the soluble aluminum alloy to obtain a first intermediate alloy; mechanically polishing the first intermediate alloy with a diamond polishing agent to obtain a second intermediate alloy; and cleaning the second intermediate alloy with anhydrous ethanol to obtain the treated soluble aluminum alloy.

[0007] Optionally, the soluble aluminum alloy is polished to obtain a first intermediate alloy, including: polishing the soluble aluminum alloy sequentially with sandpaper of 120 grit, 400 grit, 600 grit, 1200 grit, and 2000 grit to obtain the first intermediate alloy.

[0008] Optionally, cleaning the second intermediate alloy with anhydrous ethanol includes: ultrasonic cleaning the second intermediate alloy with anhydrous ethanol; wherein the ultrasonic power is 100~200W and the ultrasonic time is 3~5min.

[0009] Optionally, the electrolyte contains, by volume percentage, 70%–85% anhydrous ethanol, 5%–15% fluoroboric acid, 3%–8% glycerol, and 2%–7% perchloric acid.

[0010] Optionally, the electrolyte contains, by volume percentage, 75%–80% anhydrous ethanol, 8%–12% fluoroboric acid, 4%–6% glycerol, and 3%–5% perchloric acid.

[0011] Optionally, anhydrous ethanol, fluoroboric acid, glycerol, and perchloric acid are mixed to obtain an electrolyte for electrolytic corrosion, including: mixing anhydrous ethanol and glycerol to obtain an intermediate solution; and adding fluoroboric acid and perchloric acid while stirring the intermediate solution for 5 to 10 minutes to obtain an electrolyte for electrolytic corrosion.

[0012] Optionally, the inert electrode is a platinum electrode, and the electrode spacing between the anode and the cathode is 5~15mm.

[0013] Optionally, during the electrolytic corrosion process, the voltage of the DC power supply is 10~50V, the current is 1~5A, the temperature of the electrolytic corrosion is 25~30℃, and the time of the electrolytic corrosion is 10~60s.

[0014] Optionally, the electrolyte is kept stirred at a constant speed during the electrolytic corrosion process.

[0015] Optionally, after the electrolytic corrosion process, the soluble aluminum alloy is removed, cleaned, and dried, including: after the electrolytic corrosion process, the soluble aluminum alloy is removed, and the surface of the soluble aluminum alloy is rinsed with anhydrous ethanol 3 to 5 times; the rinsed soluble aluminum alloy is dried by cold air drying for 10 to 20 seconds.

[0016] In the exemplary embodiments of this disclosure, on the one hand, spontaneous dissolution of the alloy can be effectively avoided. Specifically, anhydrous ethanol is used as the main solvent in the electrolyte, which contains no water, fundamentally eliminating the possibility of spontaneous dissolution of the soluble aluminum alloy with water. This solves the core problems of easy sample dissolution and uncontrolled corrosion in traditional aqueous corrosion systems, ensuring that the corrosion process occurs only under electrolysis, achieving precise and controllable corrosion. On the other hand, the corrosion effect is excellent and highly controllable. Specifically, fluoroboric acid in the electrolyte, as the main corrosion component, can gently and selectively erode the grain boundaries and second phase of the soluble aluminum alloy. Perchloric acid assists in enhancing the corrosion effect, and glycerol can adjust the electrolyte viscosity, slow down the corrosion rate, avoid excessive corrosion, and improve corrosion uniformity. In addition, the electrolytic corrosion process can ensure the clear presentation of the microstructure characteristics of the soluble aluminum alloy, such as grains, grain boundaries, second phase, and internal defects, with good consistency in corrosion effect among different batches of samples. Furthermore, the solution disclosed in this disclosure is highly safe and environmentally friendly. Specifically, the electrolyte used in this disclosure avoids the large-scale use of highly corrosive reagents such as hydrofluoric acid and nitric acid, reducing safety hazards during operation. The electrolyte components are all easily treatable and low-polluting substances; the waste liquid can be discharged after simple neutralization, meeting the requirements of green and environmentally friendly development. Compared with traditional strong acid corrosion systems, it significantly reduces environmental pollution and harm to operators. Furthermore, the scheme disclosed in this disclosure is simple to operate and highly efficient. Specifically, the pretreatment, electrolyte preparation, electrolytic corrosion, and post-treatment steps in this disclosure are simple and easy to perform, requiring no complex equipment or professional operating skills. The electrolytic corrosion time is short (10~60s), and the efficiency is high, meeting the needs of batch characterization of the microstructure of soluble aluminum alloys. It is suitable for routine detection in industrial production and laboratory research. In addition, the method of this disclosure is applicable to various soluble aluminum alloys that spontaneously dissolve in aqueous solutions, including Al-Mg, Al-Sn, and Al-Ga alloys, and is not limited by alloy composition and microstructure, having broad application prospects and effectively supporting the optimization of composition, process improvement, and performance research of soluble aluminum alloys.

[0017] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0019] Figure 1The flowchart illustrates an electrolytic corrosion method for dissolvable aluminum alloy microstructures according to an embodiment of the present disclosure.

[0020] Figure 2 A schematic diagram of the metallographic structure of the soluble aluminum alloy obtained in Embodiment 1 of this disclosure is shown. Detailed Implementation

[0021] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this disclosure more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a full understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced with one or more of these specific details omitted, or other methods, processes, steps, etc., can be employed. In other instances, well-known technical solutions are not shown or described in detail to avoid obscuring various aspects of this disclosure.

[0022] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. The flowcharts shown in the drawings are merely exemplary illustrations and do not necessarily include all steps. For example, some steps may be broken down, while others may be combined or partially combined; therefore, the actual order of execution may change depending on the actual situation. Additionally, all terms such as "first," "second," etc., used below are for distinction purposes only and should not be construed as limiting the content of this disclosure.

[0023] The corrosion of soluble aluminum alloy microstructures can be achieved using chemical etching methods, such as the hydrofluoric acid-nitric acid system. However, this method has the following drawbacks: First, both hydrofluoric acid and nitric acid are highly acidic and corrosive, and soluble aluminum alloys themselves are highly chemically reactive, making them prone to over-corrosion, which destroys the microstructure and makes it impossible to accurately observe the true microstructure. Second, the hydrofluoric acid-nitric acid system inevitably contains water, and soluble aluminum alloys will spontaneously dissolve with the water in the system, which not only further exacerbates the uncontrolled corrosion but also produces a large number of reaction products that adhere to the sample surface, interfering with the observation of the microstructure. Third, the corrosion rate of chemical etching is difficult to control precisely, and the corrosion effect of different batches of samples is inconsistent, which cannot meet the needs of batch characterization. Fourth, the use of strong acidic reagents poses safety hazards, and the waste liquid is difficult to treat, which is not in line with the development trend of green environmental protection.

[0024] Electrolytic corrosion, as a more controllable corrosion technique, uses an external electric field to regulate the corrosion process and has been applied to the microstructure characterization of materials such as common aluminum alloys and stainless steel. However, a dedicated electrolytic corrosion method for soluble aluminum alloys does not yet exist. Due to the special solubility characteristics of soluble aluminum alloys, the aqueous electrolytes used in conventional electrolytic corrosion will cause the sample to spontaneously dissolve, failing to achieve effective corrosion. On the other hand, single-component non-aqueous electrolytes are difficult to balance corrosion rate and microstructure clarity, failing to meet the requirements for accurate characterization of the microstructure of soluble aluminum alloys.

[0025] To solve or at least alleviate the above problems, this disclosure provides an electrolytic corrosion method that is adaptable to soluble aluminum alloys, has controllable corrosion, is free from spontaneous dissolution interference, and is environmentally friendly and safe.

[0026] Figure 1 A flowchart illustrating the electrolytic corrosion method for dissolving aluminum alloy microstructures according to embodiments of the present disclosure is shown schematically. (Reference) Figure 1 The electrolytic corrosion method for dissolving aluminum alloy microstructures according to the present disclosure may include the following steps: S12. Pretreatment operations for grinding, polishing and cleaning of soluble aluminum alloys.

[0027] In an exemplary embodiment of this disclosure, the soluble aluminum alloy can first be polished to remove surface oxide layers, scratches, etc., to obtain a first intermediate alloy. Specifically, the soluble aluminum alloy can be polished sequentially using 120-grit, 400-grit, 600-grit, 1200-grit, and 2000-grit sandpaper to obtain the first intermediate alloy.

[0028] It should be noted that you can clean it with anhydrous ethanol after each polishing.

[0029] Next, the first intermediate alloy can be mechanically polished using a diamond polishing compound to obtain the second intermediate alloy. After polishing, the alloy surface is free of obvious scratches and defects.

[0030] Then, the second intermediate alloy can be cleaned with anhydrous ethanol to obtain a soluble aluminum alloy after processing. Specifically, the second intermediate alloy can be ultrasonically cleaned with anhydrous ethanol; the ultrasonic power is 100~200W, and the ultrasonic time is 3~5 minutes. This ensures that moisture and impurities on the surface of the alloy sample are completely removed, avoiding the spontaneous dissolution of the alloy sample due to residual moisture.

[0031] After the above pretreatment operations, the soluble aluminum alloy can be dried and kept for later use.

[0032] S14. Mix anhydrous ethanol, fluoroboric acid, glycerol, and perchloric acid to obtain the electrolyte for electrolytic corrosion.

[0033] The electrolyte contains, by volume percentage, 70%–85% anhydrous ethanol, 5%–15% fluoroboric acid, 3%–8% glycerol, and 2%–7% perchloric acid. Alternatively, it may contain 75%–80% anhydrous ethanol, 8%–12% fluoroboric acid, 4%–6% glycerol, and 3%–5% perchloric acid.

[0034] For the preparation of the electrolyte, firstly, anhydrous ethanol and glycerol are mixed to obtain an intermediate solution. Next, while stirring the intermediate solution for 5-10 minutes, fluoroboric acid and perchloric acid are added to obtain the electrolyte for electrolytic corrosion. The fluoroboric acid and perchloric acid are added slowly while stirring for 5-10 minutes to ensure uniform mixing and prevent stratification and precipitation.

[0035] It should be noted that there is no order restriction between S12 and S14 in this disclosure, that is, there is no restriction on the order in which the preparation of electrolyte and the alloy pretreatment are performed.

[0036] S16. Using a pretreated soluble aluminum alloy as the anode and an inert electrode as the cathode, an electrolytic corrosion process is performed in an electrolytic cell containing an electrolyte.

[0037] According to some embodiments of this disclosure, the inert electrode can be a platinum electrode, which has high chemical stability and does not participate in the reaction during electrolysis, thus avoiding interference with the electrolyte and corrosion effect.

[0038] The electrode spacing between the anode and cathode is controlled to be 5-15 mm. Understandably, the anode and cathode are connected to the positive and negative terminals of a DC power supply, respectively. The electrolyte is placed in the electrolytic cell, ensuring that the anode and cathode are completely submerged. Furthermore, the electrolytic cell can be made of corrosion-resistant materials, such as a polytetrafluoroethylene (PTFE) electrolytic cell.

[0039] During the electrolytic corrosion process, the DC power supply voltage is 10~50V, the current is 1~5A, the electrolytic corrosion temperature is 25~30℃, and the electrolytic corrosion time is 10~60s. Furthermore, the electrolyte is kept under constant stirring during the electrolytic corrosion process to ensure uniform corrosion.

[0040] In this embodiment, the electrolytic corrosion temperature is set to 25~30℃. This temperature range can balance corrosion rate and corrosion uniformity, avoiding excessively high temperature which would cause the electrolyte to evaporate too quickly and the corrosion rate to become out of control, and also avoiding excessively low temperature which would cause the corrosion rate to be too slow and the structure to be unclear.

[0041] S18. After the electrolytic corrosion process, the soluble aluminum alloy is removed, cleaned and dried to obtain a soluble aluminum alloy that can be used for metallographic microscopy observation of microstructures.

[0042] After the electrolytic corrosion process, the soluble aluminum alloy is removed. Then, the surface of the soluble aluminum alloy can be rinsed 3-5 times with anhydrous ethanol to remove residual electrolyte and corrosion products. Next, the rinsed soluble aluminum alloy can be dried with cold air for 10-20 seconds. Rapid drying prevents the residual anhydrous ethanol on the alloy surface from absorbing moisture from the air, thus preventing spontaneous dissolution of the sample and avoiding secondary adhesion of corrosion products.

[0043] The exemplary solutions of this disclosure will be described below with reference to embodiments and comparative examples.

[0044] Example 1

[0045] Microstructural electrolytic corrosion was performed on Al-Mg soluble aluminum alloys (e.g., Mg content 5wt%).

[0046] Step 1: Sample Pretreatment. First, the Al-Mg soluble aluminum alloy sample was cut into 10mm × 10mm × 5mm blocks. These blocks were then successively polished with 120-grit, 400-grit, 600-grit, 1200-grit, and 2000-grit sandpaper, with the surface cleaned with anhydrous ethanol after each polishing. Next, the sample was mechanically polished with 1.0μm diamond polishing compound until the surface was smooth and flat. The polished sample was then immersed in anhydrous ethanol and ultrasonically cleaned at 150W for 4 minutes. Afterward, it was allowed to air dry naturally for later use.

[0047] Step 2, electrolyte preparation. Specifically, by volume percentage, take 78% anhydrous ethanol, 10% fluoroboric acid, 5% glycerol, and 7% perchloric acid. First, pour the anhydrous ethanol and glycerol into a beaker and stir for 5 minutes to mix evenly. Then, slowly add the fluoroboric acid and perchloric acid and continue stirring for 8 minutes to obtain a uniform, non-stratified electrolytic corrosion electrolyte.

[0048] Step 3: Setting up the electrolytic corrosion apparatus. Specifically, the pretreated Al-Mg soluble aluminum alloy sample is used as the anode, and a platinum electrode is used as the cathode, connected to the positive and negative terminals of a DC power supply, respectively. The electrolyte is poured into a polytetrafluoroethylene electrolytic cell, completely immersing the anode sample and cathode, with the electrode spacing controlled at 10 mm.

[0049] Step four, electrolytic corrosion operation. Specifically, adjust the DC power supply voltage to 30V, the current to 3A, control the electrolytic corrosion temperature to 28℃, and the electrolytic corrosion time to 30s.

[0050] Step 5, post-processing. Specifically, immediately after the electrolytic corrosion is completed, the sample is removed and rinsed four times with anhydrous ethanol to remove residual electrolyte and corrosion products. Then, it is dried with cold air for 15 seconds to obtain a sample that can be used for metallographic observation.

[0051] Figure 2A schematic diagram of the metallographic structure of the soluble aluminum alloy obtained in Embodiment 1 of this disclosure is shown. (Reference) Figure 2 The sample exhibits a clear microstructure with intact and continuous grain boundaries. The second phase is uniformly distributed within the grains and at the grain boundaries. There is no excessive corrosion, no structural damage, and no products from spontaneous dissolution adhering to the surface. Grain size and micro-defects can be clearly identified, demonstrating excellent corrosion performance.

[0052] Example 2

[0053] Microstructural electrolytic corrosion was performed on Al-Sn soluble aluminum alloys (e.g., Sn content 5wt%).

[0054] Step 1: Sample Pretreatment. First, the Al-Sn soluble aluminum alloy sample was cut into 8mm × 8mm × 4mm blocks. These blocks were then successively polished with 120-grit, 400-grit, 600-grit, 1200-grit, and 2000-grit sandpaper, with the surface cleaned with anhydrous ethanol after each polishing. Next, the sample was mechanically polished with 1.0μm diamond polishing compound until the surface was smooth and flat. The polished sample was then immersed in anhydrous ethanol and ultrasonically cleaned at 120W for 3 minutes. Afterward, it was allowed to air dry naturally for later use.

[0055] Step 2, electrolyte preparation. Specifically, by volume percentage, take 80% anhydrous ethanol, 8% fluoroboric acid, 6% glycerol, and 6% perchloric acid. First, pour the anhydrous ethanol and glycerol into a beaker and stir for 6 minutes to mix evenly. Then, slowly add the fluoroboric acid and perchloric acid and continue stirring for 10 minutes to obtain a uniform, non-stratified electrolytic corrosion electrolyte.

[0056] Step 3: Setting up the electrolytic corrosion apparatus. Specifically, the pretreated Al-Sn soluble aluminum alloy sample is used as the anode, and a platinum electrode is used as the cathode, connected to the positive and negative terminals of a DC power supply, respectively. The electrolyte is poured into a polytetrafluoroethylene electrolytic cell, completely immersing the anode sample and cathode, with the electrode spacing controlled at 8 mm.

[0057] Step four, electrolytic corrosion operation. Specifically, adjust the DC power supply voltage to 20V, the current to 2A, control the electrolytic corrosion temperature to 25℃, and the electrolytic corrosion time to 40s.

[0058] Step 5, post-processing. Specifically, immediately after the electrolytic corrosion is completed, the sample is removed and rinsed 5 times with anhydrous ethanol to remove residual electrolyte and corrosion products. Then, it is dried with cold air for 12 seconds to obtain a sample that can be used for metallographic observation.

[0059] Metallographic microscopy results show that the microstructure of the sample prepared in Example 2 is clearly distinguishable, the grain morphology is complete, the grain boundaries are not blurred, the second phase particles are clearly visible, there are no traces of excessive corrosion or spontaneous dissolution, and the corrosion uniformity is good, which can meet the needs of microstructure analysis.

[0060] Example 3

[0061] Microstructural electrolytic corrosion was performed on Al-Ga soluble aluminum alloys (e.g., with a Ga content of 6 wt%).

[0062] Step 1: Sample Pretreatment. First, the Al-Ga soluble aluminum alloy sample was cut into 12mm × 12mm × 6mm blocks. These blocks were then successively polished with 120-grit, 400-grit, 600-grit, 1200-grit, and 2000-grit sandpaper, with the surface cleaned with anhydrous ethanol after each polishing. Next, the sample was mechanically polished with 1.0μm diamond polishing compound until the surface was smooth and flat. The polished sample was then immersed in anhydrous ethanol and ultrasonically cleaned at 180W for 5 minutes. Afterward, it was allowed to air dry naturally for later use.

[0063] Step 2, electrolyte preparation. Specifically, by volume percentage, take 75% anhydrous ethanol, 12% fluoroboric acid, 4% glycerol, and 9% perchloric acid. First, pour the anhydrous ethanol and glycerol into a beaker and stir for 4 minutes to mix evenly. Then, slowly add the fluoroboric acid and perchloric acid and continue stirring for 7 minutes to obtain a uniform, non-stratified electrolytic corrosion electrolyte.

[0064] Step 3: Setting up the electrolytic corrosion apparatus. Specifically, the pretreated Al-Ga soluble aluminum alloy sample is used as the anode, and a platinum electrode is used as the cathode, connected to the positive and negative terminals of a DC power supply, respectively. The electrolyte is poured into a polytetrafluoroethylene electrolytic cell, completely immersing the anode sample and cathode, with the electrode spacing controlled at 12 mm.

[0065] Step four, electrolytic corrosion operation. Specifically, adjust the DC power supply voltage to 40V, the current to 4A, control the electrolytic corrosion temperature to 30℃, and the electrolytic corrosion time to 20s.

[0066] Step 5, post-processing. Specifically, immediately after the electrolytic corrosion is completed, the sample is removed and rinsed three times with anhydrous ethanol to remove residual electrolyte and corrosion products. Then, it is dried with cold air for 18 minutes to obtain a sample that can be used for metallographic observation.

[0067] Metallographic microscopy results showed that the sample prepared in Example 3 had a clear microstructure, distinct grain boundaries, no structural distortion or excessive corrosion, and internal defects were clearly identifiable. The corrosion effect was stable and met the requirements for microstructure characterization.

[0068] Comparative Example 1

[0069] The Al-Mg soluble aluminum alloy sample in Example 1 was etched using a traditional hydrofluoric acid-nitric acid chemical etching method. The specific steps are as follows: Prepare a hydrofluoric acid-nitric acid etching solution (5% hydrofluoric acid, 10% nitric acid, and 85% water). Immerse the pretreated sample in the etching solution and etch for 10 seconds at room temperature. After etching, rinse with anhydrous ethanol and dry with cold air.

[0070] Metallographic microscopy revealed that the sample surface was severely over-corroded, the microstructure was destroyed, the grain boundaries were blurred, the second phase could not be identified, and the sample surface spontaneously dissolved due to water in the etchant, producing a large amount of white corrosion products that adhered to it, making effective microstructure analysis impossible and the corrosion effect extremely poor.

[0071] It should be noted that although the steps of the method in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or a step may be broken down into multiple steps.

[0072] Furthermore, the above figures are merely illustrative of the processes included in the method according to exemplary embodiments of this disclosure and are not intended to be limiting. It is readily understood that the processes shown in the above figures do not indicate or limit the temporal order of these processes. Additionally, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0073] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the claims.

[0074] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A method for electrolytic corrosion that can dissolve the microstructure of aluminum alloys, characterized in that, include: Pretreatment operations for grinding, polishing and cleaning of soluble aluminum alloys; Anhydrous ethanol, fluoroboric acid, glycerol, and perchloric acid are mixed to obtain the electrolyte used for electrolytic corrosion. The pretreated soluble aluminum alloy is used as the anode and the inert electrode is used as the cathode. The mixture is placed in an electrolytic cell containing the electrolyte to perform an electrolytic corrosion process. After the electrolytic corrosion process, the soluble aluminum alloy is removed, cleaned, and dried to obtain a soluble aluminum alloy that can be used for metallographic microscopy to observe microstructures.

2. The electrolytic corrosion method according to claim 1, characterized in that, Pre-treatment operations for grinding, polishing, and cleaning of soluble aluminum alloys include: The soluble aluminum alloy is polished to obtain a first intermediate alloy; The first intermediate alloy was mechanically polished using a diamond polishing agent to obtain the second intermediate alloy; The second intermediate alloy was cleaned with anhydrous ethanol to obtain a soluble aluminum alloy after treatment.

3. The electrolytic corrosion method according to claim 2, characterized in that, The soluble aluminum alloy is polished to obtain a first intermediate alloy, comprising: The soluble aluminum alloy was polished sequentially using sandpaper of 120 grit, 400 grit, 600 grit, 1200 grit, and 2000 grit to obtain the first intermediate alloy.

4. The electrolytic corrosion method according to claim 2, characterized in that, Cleaning the second intermediate alloy using anhydrous ethanol includes: The second intermediate alloy was ultrasonically cleaned using anhydrous ethanol. The ultrasonic power is 100~200W and the ultrasonic time is 3~5min.

5. The electrolytic corrosion method according to claim 1, characterized in that, The electrolyte contains, by volume percentage, 70%–85% anhydrous ethanol, 5%–15% fluoroboric acid, 3%–8% glycerol, and 2%–7% perchloric acid.

6. The electrolytic corrosion method according to claim 1 or 5, characterized in that, Anhydrous ethanol, fluoroboric acid, glycerol, and perchloric acid are mixed to obtain the electrolyte used for electrolytic corrosion, comprising: Anhydrous ethanol and glycerol are mixed to obtain an intermediate solution; During the stirring of the intermediate solution for 5-10 minutes, fluoroboric acid and perchloric acid are added to obtain the electrolyte for electrolytic corrosion.

7. The electrolytic corrosion method according to claim 1, characterized in that, The inert electrode is a platinum electrode, and the electrode distance between the anode and the cathode is 5~15mm.

8. The electrolytic corrosion method according to claim 1, characterized in that, During the electrolytic corrosion process, the DC power supply voltage is 10~50V, the current is 1~5A, the electrolytic corrosion temperature is 25~30℃, and the electrolytic corrosion time is 10~60s.

9. The electrolytic corrosion method according to claim 1 or 8, characterized in that, During the electrolytic corrosion process, the electrolyte is kept stirred at a constant speed.

10. The electrolytic corrosion method according to claim 1, characterized in that, After the electrolytic corrosion process, the soluble aluminum alloy is removed, cleaned, and dried, including: After the electrolytic corrosion process, the soluble aluminum alloy is removed and its surface is rinsed 3 to 5 times with anhydrous ethanol. The soluble aluminum alloy after rinsing is dried by blowing cold air for 10-20 seconds.

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