Aluminum alloy etching solution and preparation method and etching process thereof
By using an aluminum alloy etching solution containing hydrochloric acid, nitric acid, zinc acetate, and glycerin, the problem of poor environmental performance in aluminum alloy etching processes has been solved, achieving high-efficiency etching, low cost, and low wastewater discharge, while also ensuring strong coating adhesion.
Patent Information
- Application Number
- CN202510950569.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-10
- Publication Date
- 2025-11-14
AI Technical Summary
Existing aluminum alloy etching processes suffer from poor environmental performance, high costs, large wastewater discharges, and long process flows, making it difficult to meet environmental protection requirements.
An aluminum alloy etching solution containing 10%–20% hydrochloric acid, 0.7%–5% nitric acid, 0.5%–2% zinc acetate, and 1%–3% glycerol is used in the etching process. This process results in a shorter etching time, eliminates the need for a ash removal step, reduces costs, and minimizes wastewater discharge.
It achieves the surface roughness requirements of aluminum alloy workpieces in a very short time, reduces etching process costs, reduces wastewater discharge, improves environmental friendliness, and provides strong coating adhesion.
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Abstract
Description
Technical Field
[0001] This application relates to the field of metal surface treatment technology, and in particular to an aluminum alloy etching solution and its preparation method and etching process. Background Technology
[0002] Aluminum workpieces need to meet certain surface roughness requirements to pass coating adhesion requirements. Currently, the common methods for achieving surface roughness in aluminum alloys are sandblasting and chemical etching. These two processes are used differently depending on the working conditions.
[0003] Traditional chemical etching requires two or three alternating acid-base etching processes to achieve the desired roughness, consuming large quantities of chemicals and causing significant environmental pollution. Some companies have abandoned chemical etching due to their inability to meet environmental emission standards. Therefore, developing a highly efficient, environmentally friendly, and low-cost chemical etching process for aluminum alloys is a pressing technical challenge that the industry needs to address. Summary of the Invention
[0004] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes an aluminum alloy etching solution with high etching efficiency, which can achieve the required roughness of aluminum alloy workpieces in a very short time, and can eliminate the need for dust removal, shorten the etching process flow, reduce etching process costs, greatly reduce wastewater discharge, and improve the environmental friendliness of the process.
[0005] This application also proposes a method for preparing an aluminum alloy etching solution. The obtained aluminum alloy etching solution does not contain toxic, harmful, or recalcitrant chemicals. When applied to the etching process, it has a high etching capacity, can make aluminum alloy workpieces reach the required roughness in a very short time, and can eliminate the need for dust removal, shorten the etching process flow, reduce the etching process cost, greatly reduce wastewater discharge, and improve the environmental friendliness of the process.
[0006] This application also proposes an etching process based on aluminum alloy etching solution, which has high etching efficiency, can make aluminum alloy workpieces reach the required roughness in a very short time, and can eliminate the need for dust removal, shorten the etching process flow, reduce the etching process cost, greatly reduce wastewater discharge, and improve the environmental friendliness of the process.
[0007] The aluminum alloy etching solution according to the first aspect of this application comprises the following raw materials in weight percentages: 10% to 20% hydrochloric acid, 0.7% to 5% nitric acid, 0.5% to 2% zinc acetate, 1% to 3% glycerol, and the balance being water.
[0008] The aluminum alloy etching solution described in the embodiments of this application has at least the following beneficial effects: The aluminum alloy etching solution described in the embodiments of this application does not contain toxic, harmful, or difficult-to-degrade chemicals. When applied to the etching process, it has a high etching capacity, can make the aluminum alloy workpiece reach the required roughness in a very short time, and can eliminate the need for dust removal, shorten the etching process flow, reduce the etching process cost, greatly reduce wastewater discharge, and improve the environmental friendliness of the process.
[0009] According to the aluminum alloy etching solution described in the first aspect of this application, the hydrochloric acid has a mass concentration of 36%.
[0010] According to the aluminum alloy etching solution described in the first aspect of this application, the mass concentration of the nitric acid is 68%.
[0011] The method for preparing the aluminum alloy etching solution according to the second aspect of this application includes: adding hydrochloric acid and nitric acid in water at a specified mass percentage, stirring until uniform, then adding zinc acetate and glycerin in a specified mass percentage to the solution, mixing until uniform, and the resulting agent is the aluminum alloy etching solution.
[0012] The method for preparing aluminum alloy etching solution according to the second aspect of the present application has at least the following beneficial effects: the aluminum alloy etching solution obtained by the above preparation method does not contain toxic, harmful and difficult-to-degrade chemicals. When applied to the etching process, it has a high etching capacity, can make aluminum alloy workpieces reach the required roughness in a very short time, and can eliminate the need for ash removal, shorten the etching process flow, reduce the etching process cost, greatly reduce wastewater discharge, and improve the environmental friendliness of the process.
[0013] The etching process based on aluminum alloy etching solution according to the third aspect of this application includes: Degreasing: The aluminum alloy workpiece is cleaned and degreased by immersing it in a strong alkaline degreasing agent; First water wash: The aluminum alloy workpiece is washed with water; Etching; etching the aluminum alloy workpiece by placing it in the aluminum alloy etching solution described in the first aspect of this application; Second water wash: The aluminum alloy workpiece is washed with water; Drying: The aluminum alloy workpiece is dried.
[0014] The etching process based on aluminum alloy etching solution according to the third aspect of the present application has at least the following beneficial effects: by using the aluminum alloy etching solution described in the first aspect of the present application for etching, it has a high etching capacity, can make the aluminum alloy workpiece reach the required roughness in a very short time, and can eliminate the need for dust removal, shorten the etching process flow, reduce the etching process cost, greatly reduce wastewater discharge, and improve the environmental friendliness of the process.
[0015] According to the etching process based on aluminum alloy etching solution described in the third aspect of this application, the degreasing time, first water washing time, second water washing time and etching time of the aluminum alloy workpiece are all 120 seconds.
[0016] According to the etching process based on aluminum alloy etching solution described in the third aspect of this application, the degreasing temperature of the aluminum alloy workpiece is 50-80℃, the water washing temperature of the aluminum alloy workpiece is room temperature, the etching temperature of the aluminum alloy workpiece is 40-60℃, and the drying temperature of the aluminum alloy workpiece is 80-150℃.
[0017] According to the etching process based on aluminum alloy etching solution described in the third aspect of this application, in the first and second water washes of the aluminum alloy workpiece, one or more mixtures of tap water, distilled water, deionized water or ultrapure water are used.
[0018] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Detailed Implementation
[0019] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of 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.
[0020] The first aspect of this application provides an aluminum alloy etching solution comprising the following raw materials in weight percentages: 10%–20% hydrochloric acid, 0.7%–5% nitric acid, 0.5%–2% zinc acetate, 1%–3% glycerol, and the balance being water.
[0021] The aluminum alloy etching solution described in this application embodiment does not contain toxic, harmful, or recalcitrant chemicals. When applied to the etching process, it has a highly efficient etching capability, enabling aluminum alloy workpieces to achieve the required roughness in a very short time. It also eliminates the need for dust removal, shortens the etching process flow, reduces etching costs, significantly reduces wastewater discharge, and improves the environmental friendliness of the process.
[0022] The hydrochloric acid has a mass concentration of 36%, and the nitric acid has a mass concentration of 68%.
[0023] The second aspect of this application provides a method for preparing an aluminum alloy etching solution, comprising: adding hydrochloric acid and nitric acid in water at a specified mass percentage, stirring until homogeneous, then adding zinc acetate and glycerin in a specified mass percentage to the solution, mixing until homogeneous, and the resulting reagent being the aluminum alloy etching solution.
[0024] The aluminum alloy etching solution obtained by the above preparation method does not contain toxic, harmful, or recalcitrant chemicals. When applied to the etching process, it has a high etching capacity, can make aluminum alloy workpieces reach the required roughness in a very short time, and can eliminate the need for dust removal, shorten the etching process, reduce the etching process cost, greatly reduce wastewater discharge, and improve the environmental friendliness of the process.
[0025] A third aspect of this application provides an etching process based on an aluminum alloy etching solution, comprising: Degreasing: The aluminum alloy workpiece is cleaned and degreased by immersing it in a strong alkaline degreasing agent; First wash: Wash the aluminum alloy workpiece with water; Etching; etching an aluminum alloy workpiece by immersing it in the aluminum alloy etching solution described in the first aspect of this application. Second wash: The aluminum alloy workpiece is washed with water; Drying: Drying the aluminum alloy workpiece.
[0026] Etching with the aluminum alloy etching solution described in the first aspect of this application has a high etching capacity, which can make the aluminum alloy workpiece reach the required roughness in a very short time. It can also eliminate the need for dust removal, shorten the etching process, reduce the etching process cost, greatly reduce wastewater discharge, and improve the environmental friendliness of the process.
[0027] The degreasing time, first water rinse time, second water rinse time, and etching time are all 120 seconds.
[0028] The degreasing temperature is 50-80℃, the water washing temperature is room temperature, the etching temperature for aluminum alloy workpieces is 40-60℃, and the drying temperature is 80-150℃.
[0029] In the first and second water washes of aluminum alloy workpieces, one or a mixture of tap water, distilled water, deionized water, or ultrapure water is used.
[0030] The following embodiments are further illustrations of the present invention, but not limitations thereof. Unless otherwise specified, the equipment and reagents used in the present invention are commercially available products conventional in this technical field.
[0031] In this embodiment, the resistance of the ceramic coating to detach from the aluminum alloy substrate was assessed by cutting the coating with a right-angled grid pattern and penetrating to the substrate. This test was conducted according to the method provided in the national standard GB / T 9286-2021 "Cross-cut Test for Paints and Varnishes". The test results are graded as shown in Table 1. Table 1. Grading of Test Results
[0032] Comparative Example 1: After the clean aluminum alloy workpiece is degreased and its roughness is tested, it is sprayed with water-based ceramic coating and oil-based coating. After the coating is cured, the adhesion is tested according to the method provided in the national standard "GB / T 9286-2021 Paints and Varnishes Cross-cut Test".
[0033] Example 1: An aluminum alloy etching solution, characterized in that it comprises the following raw materials in the following mass percentages: 15% hydrochloric acid, 3% nitric acid, 1% zinc acetate, 2% glycerol, and the balance being water. The hydrochloric acid has a mass concentration of 36%, and the nitric acid has a mass concentration of 68%.
[0034] Add hydrochloric acid and nitric acid to water at a specified mass percentage, stir until homogeneous, then add zinc acetate and glycerin at a specified mass percentage to the solution and mix until homogeneous. The resulting reagent is the aluminum alloy etching solution.
[0035] The aluminum alloy workpiece is immersed in the etching process as follows: degreasing—first water rinse—etching—second water rinse—drying. Each process has a dwell time of 120 seconds, the degreasing temperature is 60℃, the water rinse temperature is room temperature, the etching temperature is 50℃, and the drying temperature is 100℃.
[0036] After the roughness of the etched aluminum alloy workpiece is tested, water-based ceramic coating and oil-based coating are sprayed on it. After the coating is cured, the adhesion is tested according to the method provided in the national standard "GB / T 9286-2021 Paints and Varnishes Cross-cut Test".
[0037] The roughness and adhesion test results of the samples obtained in Example 1 and Comparative Example 1 are shown in Table 2. The only difference between Comparative Example 1 and Example 1 is that the aluminum alloy workpiece was not treated with aluminum alloy etching solution.
[0038] Table 2. Roughness and adhesion test results of Example 1 and Comparative Example 1
[0039] According to the test results in Table 2, the aluminum alloy workpiece treated with the aluminum alloy etching solution of Example 1 can achieve a roughness of Ra=2.32μm. The adhesion of both water-based and oil-based coatings reaches level 0, indicating that the coating has a strong bond with the substrate.
[0040] Example 2: The only difference from Example 1 is that, in this example, the aluminum alloy etching solution includes the following raw materials by mass percentage: 10% hydrochloric acid, 0.7% nitric acid, 0.5% zinc acetate, 1% glycerol, and the balance being water.
[0041] Example 3: The only difference from Example 1 is that in this example, the aluminum alloy etching solution includes the following raw materials by mass percentage: 20% hydrochloric acid, 5% nitric acid, 2% zinc acetate, 3% glycerol, and the balance is water.
[0042] The roughness and adhesion test results of the samples obtained in Examples 1 to 3 and Comparative Example 1 are shown in Table 3. The only difference between Comparative Example 1 and Examples 1 to 3 is that the aluminum alloy workpiece was not treated with aluminum alloy etching solution.
[0043] Table 3. Roughness and adhesion test results of Examples 1 to 3 and Comparative Example 1
[0044] According to the test results in Table 3, comparing Comparative Example 1 with Examples 1 to 3, it can be seen that the adhesion of Examples 1 to 3 is significantly greater than that of Comparative Example 1. This indicates that using the aluminum alloy etching solution of this application to treat aluminum alloy workpieces can produce a large roughness on the surface of the aluminum alloy workpieces. Furthermore, the adhesion of both water-based and oil-based coatings reaches level 0, indicating that the coating has a strong bond with the substrate.
[0045] Example 4: The only difference from Example 1 is that in this example, the degreasing temperature is 50°C.
[0046] Example 5: The only difference from Example 1 is that in this example, the degreasing temperature is 80°C.
[0047] The roughness and adhesion test results of Examples 1, 4 and 5 are shown in Table 4. The only difference between Examples 4 and 5 and Example 1 is the degreasing temperature.
[0048] Table 4. Roughness and adhesion test results for Examples 1, 4, and 5
[0049] According to the test results in Table 4, comparing Examples 4 and 5 with Example 1, it can be seen that the higher the degreasing temperature, the greater the roughness. Using different degreasing temperatures to treat aluminum alloy workpieces can achieve a good roughness level. Moreover, the adhesion of both water-based and oil-based coatings reaches level 0, indicating that the coating has a strong bond with the substrate.
[0050] Example 6: The only difference from Example 1 is that in this example, the etching temperature is 40°C.
[0051] Example 7: The only difference from Example 1 is that in this example, the etching temperature is 60°C.
[0052] The roughness and adhesion test results of Examples 1, 6 and 7 are shown in Table 5. The only difference between Examples 6 and 7 and Example 1 is the etching temperature.
[0053] Table 5. Roughness and adhesion test results for Examples 1, 6, and 7.
[0054] According to the test results in Table 5, comparing Examples 6 and 7 with Example 1, it can be seen that the higher the etching temperature, the greater the roughness. Using different etching temperatures to process aluminum alloy workpieces can achieve a good roughness level. Moreover, the adhesion of both water-based and oil-based coatings reaches level 0, indicating that the coating has a strong bond with the substrate.
[0055] The embodiments of this application have been described in detail above, but this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.
Claims
1. An aluminum alloy etching solution, characterized in that, It contains the following raw materials in the following weight percentages: 10%–20% hydrochloric acid, 0.7%–5% nitric acid, 0.5%–2% zinc acetate, 1%–3% glycerol, and the balance being water.
2. The aluminum alloy etching solution according to claim 1, characterized in that, The mass concentration of the hydrochloric acid is 36%.
3. The aluminum alloy etching solution according to claim 1, characterized in that, The mass concentration of the nitric acid is 68%.
4. A method for preparing an aluminum alloy etching solution, characterized in that, include: Add hydrochloric acid and nitric acid to water at a specified mass percentage, stir until homogeneous, then add zinc acetate and glycerin at a specified mass percentage to the solution and mix until homogeneous. The resulting reagent is the aluminum alloy etching solution.
5. An etching process based on aluminum alloy etching solution, characterized in that, include: Degreasing: The aluminum alloy workpiece is cleaned and degreased by immersing it in a strong alkaline degreasing agent; First water wash: The aluminum alloy workpiece is washed with water; Etching; The aluminum alloy workpiece is etched in the aluminum alloy etching solution according to any one of claims 1 to 3. Second water wash: The aluminum alloy workpiece is washed with water; Drying: The aluminum alloy workpiece is dried.
6. The etching process according to claim 5, characterized in that, The degreasing time, first water rinse time, second water rinse time, and etching time are all 120 seconds.
7. The etching process according to claim 5, characterized in that, The degreasing temperature is 50-80℃, the water washing temperature is room temperature, the etching temperature is 40-60℃, and the drying temperature of the aluminum alloy workpiece is 80-150℃.
8. The etching process according to claim 5, characterized in that, In the first and second water washes of the aluminum alloy workpiece, one or a mixture of tap water, distilled water, deionized water, or ultrapure water is used.