Process method for improving hardness of 2A11 aluminum alloy hard anodized film layer

Abstract

The invention discloses a process method for improving the hardness of a 2A11 aluminum alloy hard anodized film layer. The process method comprises the following steps: (1) pretreatment; selecting a test bar made of a 2A11 material, cleaning the test bar by adopting an organic solvent, and carrying out alkali etching to remove an oxidation film on the surface; (2) washing; washing with water for at least 2 minutes, checking the continuity of a water film, ensuring that the water film is not broken for at least 30 seconds, and ensuring that the surface state of the test bar meets the quality requirement before anodizing; (3) hard anodizing; putting the test bar subjected to water washing treatment into a sulfuric acid solution, and carrying out anodizing treatment; (4) washing; washing for at least 2 minutes, removing the sulfuric acid solution on the surface of the test bar, and not carrying out sealing treatment; (5) detecting; the color of the film layer of the test bar is tea green to yellowish brown, the color is uniform and consistent, and the thickness of the film layer is 32-40 [mu] m. By means of the technological method, the hardness of the hard anodized film layer of the 2A11 aluminum alloy difficult to oxidize can be improved to be larger than or equal to HV302.

Description

Technical Field

[0001] The present invention relates to the technical field of surface treatment, and more specifically, to a process method for improving the hardness of the hard anodic oxidation film of 2A11 aluminum alloy. Background Art

[0002] 2A11 aluminum alloy is a typical alloy in hard aluminum and is widely used. In order to improve its friction and wear performance, a hard anodizing treatment method in a sulfuric acid solution is adopted to obtain an oxide film layer with a hardness higher than that of the substrate. Since 2A11 aluminum alloy has a relatively high copper content, the precipitation phase formed during the heat treatment is difficult to form a film, so the hardness of the film layer after hard anodizing is relatively low, generally only about HV260 - HV270.

[0003] In order to meet the performance requirements of the product, without changing the sulfuric acid concentration, it is necessary to further improve the hardness of the hard anodic oxidation film of 2A11 aluminum alloy. Summary of the Invention

[0004] In view of this, the present invention provides a process method for improving the hardness of the hard anodic oxidation film of 2A11 aluminum alloy.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A process method for improving the hardness of the hard anodic oxidation film of 2A11 aluminum alloy, comprising the following steps:

[0007] (1) Pretreatment

[0008] Select a test bar of 2A11 material and clean the test bar with an organic solvent, followed by alkali etching to remove the oxide film on the surface;

[0009] (2) Water washing

[0010] Wash with water for at least 2 min, and check the continuity of the water film to ensure that the water film does not break for at least 30 s, so as to ensure that the surface state of the test bar meets the quality requirements before anodizing;

[0011] (3) Hard anodizing

[0012] Put the test bar after water washing treatment into a sulfuric acid solution for anodizing treatment;

[0013] (4) Water washing

[0014] Wash with water for at least 2 min to remove the sulfuric acid solution on the surface of the test bar, and do not perform sealing treatment;

[0015] (5) Detection

[0016] The color of the film layer of the test bar is tea green to yellowish brown, the color is uniform, and the film layer thickness is 32 μm - 40 μm.

[0017] Preferably, the test bar described in step (1) has a specification of Φ25mm×100mm.

[0018] Preferably, the organic solvent described in step (1) is acetone; the base is sodium hydroxide.

[0019] Preferably, the concentration of the sulfuric acid solution described in step (3) is 290 - 310 g / L.

[0020] Preferably, the parameters of the anodizing treatment described in step (3) are: temperature 1.0 - 2.0 °C, current density 3 A / dm 2 , rising to the rated current intensity within 20 min, the termination voltage is 45 ± 3 V, and the oxidation time is 52 ± 2 min.

[0021] Through the above technical solution, it can be seen that compared with the prior art, the process method of the present invention can increase the hardness of the hard anodized film layer of 2A11 aluminum alloy, which is difficult to oxidize, to ≥ HV302. Detailed implementation mode

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0023] Embodiment 1

[0024] This embodiment provides a process method for increasing the hardness of the hard anodized film layer of 2A11 aluminum alloy, including the following steps:

[0025] (1) Pretreatment

[0026] Prepare a test bar of 2A11 material (specification: Φ25mm×100mm), the surface of the test bar is flat, smooth, without spots, scratches and rust, clean the test bar with acetone, and perform alkali etching to remove the surface oxide film.

[0027] (2) Water washing

[0028] Wash with water for at least 2 min, check the continuity of the water film, ensure that the water film does not break for at least 30 s, and ensure that the surface state of the test bar meets the quality requirements before anodizing.

[0029] (3) Hard anodizing

[0030] The concentration of the sulfuric acid solution is 290 g / L, the temperature is 1.0 °C, and the current density is 3 A / dm 2, It rises to the rated current intensity within 20 min, the termination voltage is 45 ± 3 V, and the oxidation time is 52 ± 2 min.

[0031] (4) Water washing

[0032] Wash with deionized water for at least 2 min to remove the sulfuric acid solution on the surface of the test bar. No sealing treatment is carried out.

[0033] (5) Detection

[0034] The color of the film layer of the test bar is from tea green to tawny, the color is uniform, and the film layer thickness is 35 μm.

[0035] Example 2

[0036] This example provides a process method for improving the hardness of the hard anodic oxidation film layer of 2A11 aluminum alloy, including the following steps:

[0037] (1) Pretreatment

[0038] Prepare a test bar of 2A11 material (specification: Φ25mm × 100mm). The surface of the test bar is flat, smooth, without spots, scratches and rust. Clean the test bar with acetone and carry out alkali etching to remove the surface oxide film.

[0039] (2) Water washing

[0040] Wash with water for at least 2 min, check the continuity of the water film, ensure that the water film does not break for at least 30 s, and ensure that the surface state of the test bar meets the quality requirements before anodization.

[0041] (3) Hard anodization

[0042] The concentration of the sulfuric acid solution is about 310 g / L, the temperature is 2 °C, and the current density is 3 A / dm 2 , It rises to the rated current intensity within 20 min, the termination voltage is 45 ± 3 V, and the oxidation time is 52 ± 2 min.

[0043] (4) Water washing

[0044] Wash with deionized water for at least 2 min to remove the sulfuric acid solution on the surface of the test bar. No sealing treatment is carried out.

[0045] (5) Detection

[0046] After the test bar is anodized, the color of the film layer is from tea green to tawny, the color is uniform, and the film layer thickness is 33 μm.

[0047] Example 3

[0048] This example provides a process method for improving the hardness of the hard anodic oxidation film layer of 2A11 aluminum alloy, including the following steps:

[0049] (1) Pretreatment

[0050] Prepare test bars of 2A11 material (specification: Φ25mm×100mm). The surfaces of the test bars are flat, smooth, free of spots, scratches and rust. Clean the test bars with acetone and perform alkaline etching to remove the oxide film on the surface.

[0051] (2) Water washing

[0052] Wash with water for at least 2 min, check the continuity of the water film, ensure that the water film does not break for at least 30 s, and ensure that the surface state of the test bars meets the quality requirements before anodizing.

[0053] (3) Hard anodizing

[0054] The concentration of the sulfuric acid solution is about 300 g / L, the temperature is 1.5 °C, and the current density is 3 A / dm 2 , rise to the rated current intensity within 20 min, the termination voltage is 45 ± 3 V, and the oxidation time is 52 ± 2 min.

[0055] (4) Water washing

[0056] Wash with deionized water for at least 2 min to remove the sulfuric acid solution on the surface of the test bars. Do not perform sealing treatment.

[0057] (5) Detection

[0058] After the test bars are anodized, the color of the film layer is tea green to tawny brown, the color is uniform, and the film layer thickness is 40 μm.

[0059] Example 4

[0060] This example provides a process method for improving the hardness of the hard anodized film layer of 2A11 aluminum alloy, including the following steps:

[0061] (1) Pretreatment

[0062] Prepare test bars of 2A11 material (specification: Φ25mm×100mm). The surfaces of the test bars are flat, smooth, free of spots, scratches and rust. Clean the test bars with acetone and perform alkaline etching to remove the oxide film on the surface.

[0063] (2) Water washing

[0064] Wash with water for at least 2 min, check the continuity of the water film, ensure that the water film does not break for at least 30 s, and ensure that the surface state of the test bars meets the quality requirements before anodizing.

[0065] (3) Hard anodizing

[0066] The concentration of the sulfuric acid solution is about 300 g / L, the temperature is 1.8 °C, and the current density is 3 A / dm 2, It rises to the rated current intensity within 20 min, the termination voltage is 45 ± 3 V, and the oxidation time is 52 ± 2 min.

[0067] (4) Water washing

[0068] Wash with deionized water for at least 2 min to remove the sulfuric acid solution on the surface of the test bar. No sealing treatment is carried out.

[0069] (5) Detection

[0070] After the test bar is anodized, the color of the film layer is from tea green to tawny, the color is uniform, and the film layer thickness is 36 μm.

[0071] Example 5

[0072] This example provides a process method for improving the hardness of the hard anodized film layer of 2A11 aluminum alloy, including the following steps:

[0073] (1) Pretreatment

[0074] Prepare a test bar of 2A11 material (specification: Φ25mm×100mm). The surface of the test bar is flat, smooth, without spots, scratches and rust. Clean the test bar with acetone and carry out alkali etching to remove the oxide film on the surface.

[0075] (2) Water washing

[0076] Wash with water for at least 2 min, check the continuity of the water film, ensure that the water film does not break for at least 30 s, and ensure that the surface state of the test bar meets the quality requirements before anodization.

[0077] (3) Hard anodization

[0078] The concentration of the sulfuric acid solution is about 305 g / L, the temperature is 1.5 °C, and the current density is 3 A / dm 2 , It rises to the rated current intensity within 20 min, the termination voltage is 45 ± 3 V, and the oxidation time is 52 ± 2 min.

[0079] (4) Water washing

[0080] Wash with deionized water for at least 2 min to remove the sulfuric acid solution on the surface of the test bar. No sealing treatment is carried out.

[0081] (5) Detection

[0082] After the test bar is anodized, the color of the film layer is from tea green to tawny, the color is uniform, and the film layer thickness is 35 μm.

[0083] Example 6

[0084] This example provides a process method for improving the hardness of the hard anodized film layer of 2A11 aluminum alloy, including the following steps:

[0085] (1) Pretreatment

[0086] Prepare test bars of 2A11 material (specification: Φ25mm×100mm). The surfaces of the test bars are flat, smooth, without spots, scratches and rust. Clean the test bars with acetone and perform alkali etching to remove the oxide film on the surface.

[0087] (2) Water washing

[0088] Wash with water for at least 2 min, check the continuity of the water film, ensure that the water film does not break for at least 30 s, and ensure that the surface state of the test bar meets the quality requirements before anodizing.

[0089] (3) Hard anodizing

[0090] The concentration of the sulfuric acid solution is about 300 g / L, the temperature is 1.5 °C, and the current density is 3 A / dm 2 , rise to the rated current intensity within 20 min, the termination voltage is 45 ± 3 V, and the oxidation time is 52 ± 2 min.

[0091] (4) Water washing

[0092] Wash with deionized water for at least 2 min to remove the sulfuric acid solution on the surface of the test bar. Do not perform sealing treatment.

[0093] (5) Detection

[0094] After the test bar is anodized, the color of the film layer is from tea green to tawny, the color is uniform, and the film layer thickness is 32 μm.

[0095] Effect detection

[0096] Use a microhardness tester to detect the hardness of the film layer. The detection results are shown in Table 1:

[0097] Table 1

[0098]

[0099] As can be seen from the above, for 2A11 aluminum alloy, by using the process parameters of the present invention, the hardness of the hard anodized film layer can be increased to ≥HV302, and the appearance of the film layer meets the requirements.

[0100] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and reference can be made to the description in the method part for relevant parts.

[0101] The foregoing description of the disclosed embodiments enables those skilled in the art to practice or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A process method for improving the hardness of the hard anodized film of 2A11 aluminum alloy, characterized in that, It includes the following steps: (1) Pretreatment Select a test bar made of 2A11 material and clean the test bar with an organic solvent, followed by alkali etching to remove the oxide film on the surface; (2) Water washing Wash with water for at least 2 minutes, and check the continuity of the water film to ensure that the water film does not break for at least 30 seconds, ensuring that the surface state of the test bar meets the quality requirements before anodization; (3) Hard anodization Put the test bar after water washing treatment into a sulfuric acid solution for anodization treatment; (4) Water washing Wash with water for at least 2 minutes to remove the sulfuric acid solution on the surface of the test bar, without performing sealing treatment; (5) Detection The color of the film layer of the test bar is tea green to tawny, with uniform color, and the film layer thickness is 32μm - 40μm.

2. The process method for improving the hardness of the hard anodized film of 2A11 aluminum alloy according to claim 1, characterized in that, The specification of the test bar described in step (1) is Φ25mm×100mm.

3. The process method for improving the hardness of the hard anodized film of 2A11 aluminum alloy according to claim 1, characterized in that, The organic solvent described in step (1) is acetone; the alkali is sodium hydroxide.

4. The process method for improving the hardness of the hard anodized film of 2A11 aluminum alloy according to claim 1, characterized in that, The concentration of the sulfuric acid solution described in step (3) is 290 - 310g / L.

5. The process method for improving the hardness of the hard anodized film of 2A11 aluminum alloy according to claim 1, characterized in that, The parameters of the anodizing treatment described in step (3) are as follows: temperature 1.0 - 2.0 °C, current density 3 A / dm 2 , rising to the rated current intensity within 20 min, termination voltage 45 ± 3 V, oxidation time 52 ± 2 min.

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