A metal piece and a method for manufacturing the same

Abstract

This application relates to a metal component comprising a metal substrate and a hydrophobic layer located on at least a portion of the surface of the metal substrate. The hydrophobic layer is primarily composed of zirconium oxide and has a coral-like structure and / or a mesh-like structure. The hydrophobic layer in this metal component exhibits excellent adhesion to the metal substrate and possesses excellent hydrophobicity. Furthermore, the hydrophobic layer is predominantly composed of zirconium oxide, is white in color, and serves a surface decorative function.

Description

Technical Field

[0001] This application relates to the field of metal surface treatment technology, specifically to a metal part and its preparation method. Background Technology

[0002] With the improvement of consumption level, consumers not only pay attention to the quality of electronic products, but also to the texture, feel and anti-fingerprint effect of their appearance surface. The surface decoration of electronic products with superhydrophobic film is worth studying. Summary of the Invention

[0003] The purpose of this application is to overcome the problems existing in the prior art and provide a metal part and its preparation method. The hydrophobic layer of the metal part not only has excellent superhydrophobicity, but also has zirconium oxide as the main component, is white in color, and has surface decoration properties.

[0004] A first aspect of this application is to provide a metal part comprising a metal substrate and a hydrophobic layer located on at least a portion of the surface of the metal substrate, the main component of the hydrophobic layer containing zirconium oxide, and the hydrophobic layer having a coral-like structure and / or a mesh structure.

[0005] Preferably, the hydrophobic layer contains at least 50 wt% zirconium oxide.

[0006] Preferably, the hydrophobic layer contains an organic compound containing fluorine (F).

[0007] Preferably, the thickness of the hydrophobic layer is 5-30µm.

[0008] Preferably, the water droplet angle of the hydrophobic layer is greater than 150 degrees.

[0009] Preferably, a coating layer is formed on the surface of the hydrophobic layer away from the metal substrate.

[0010] Preferably, the metal substrate includes at least one of aluminum, aluminum alloy, magnesium, and magnesium alloy substrate.

[0011] A second aspect of this application is to provide a method for preparing the aforementioned metal part, comprising the following steps:

[0012] The metal substrate is placed in an electrolyte for micro-arc oxidation;

[0013] The electrolyte comprises zirconium salt, organic acid, fluoride and hydrogen peroxide, and the pH of the electrolyte is less than 6.5.

[0014] The voltage for the micro-arc oxidation is 300-640V.

[0015] Preferably, the process further includes organic modification of the metal substrate after micro-arc oxidation.

[0016] Preferably, the organic modification treatment includes: immersing the micro-arc oxidized metal substrate in AF anti-fingerprint solution for modification.

[0017] Preferably, the frequency of the micro-arc oxidation is 200-3000Hz, and the duration of the micro-arc oxidation is 5-120min.

[0018] Preferably, the temperature of the electrolyte is controlled at 10-30℃.

[0019] Preferably, the electrolyte comprises the following components by weight:

[0020] 2-40 g / L zirconium salt, 0.5-10 g / L organic acid, 0.5-5 g / L fluoride, 0.1-10 g / L hydrogen peroxide.

[0021] Preferably, the zirconium salt includes at least one of zirconium acetate, zirconium carbonate, and potassium fluorozirconate.

[0022] Preferably, the organic acid includes at least one of oxalic acid, citric acid, and tartaric acid.

[0023] Preferably, the fluoride includes at least one of sodium fluoride, potassium fluoride, and hydrofluoric acid.

[0024] Preferably, the electrolyte further includes a pH adjuster.

[0025] Preferably, the metal substrate is subjected to degreasing, acid etching, and neutralization treatment before the micro-arc oxidation is performed.

[0026] The metal part provided in this application contains a hydrophobic layer with a coral-like structure and / or a mesh structure, which can reduce the contact between liquid and surface, improve the hydrophobicity of the hydrophobic layer, and the hydrophobic layer has a good bonding force with the metal substrate; in addition, the hydrophobic layer is mainly composed of zirconium oxide, is white in color, and has surface decoration properties. Attached Figure Description

[0027] Figure 1 This is an electron microscope image of the hydrophobic layer of the metal part provided in Embodiment 1 of this application;

[0028] Figure 2 This is an electron microscope image of the hydrophobic layer of the metal part provided in Comparative Example 1 of this application. Detailed Implementation

[0029] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0030] This application provides a metal part, including a metal substrate and a hydrophobic layer located on at least a portion of the surface of the metal substrate, wherein the main component of the hydrophobic layer contains zirconium oxide, and the hydrophobic layer has a coral-like structure and / or a mesh structure.

[0031] Specifically, the hydrophobic layer has a coral-like structure and / or a mesh-like structure formed by multiple interconnected synaptic structures, which can reduce the contact between the liquid and the surface, improve the hydrophobicity of the layer, and since the hydrophobic layer is grown in situ on the metal substrate, it has a good bonding force with the metal substrate. In addition, the main component of the hydrophobic layer is zirconium oxide, which is white in color, giving the hydrophobic layer a white appearance. Therefore, the hydrophobic layer of this application can both improve the hydrophobicity of the metal part and enhance the surface decoration effect of the metal part.

[0032] In some embodiments, the hydrophobic layer contains at least 50 wt% zirconium oxide. Preferably, the hydrophobic layer contains at least 70 wt% zirconium oxide, further improving the appearance of the metal part.

[0033] In some embodiments, the hydrophobic layer contains an organic compound containing phosphorus (F), which can further improve the hydrophobicity of the hydrophobic layer. The F-containing organic compound may be one or more of trifluoromethyl vinyl ether, hexadecylfluoroheptane, tridecafluorohexylethyltrimethoxysilane, trifluoropropylmethylpolysiloxane, and trifluoropropylmethyldimethoxysilane.

[0034] In some embodiments, the thickness of the hydrophobic layer is 5-30µm. If the hydrophobic layer is too thin, the salt spray performance of the membrane is poor; if the hydrophobic layer is too thick, the surface of the membrane is too rough, resulting in poor feel and appearance.

[0035] In some embodiments, the hydrophobic layer has a droplet angle greater than 150 degrees and exhibits superhydrophobicity.

[0036] In some embodiments, a coating layer is formed on the surface of the hydrophobic layer away from the metal substrate. The coating layer may be a smooth or frosted optical film layer, further enhancing the exterior decorative effect of the metal part.

[0037] In some embodiments, the metal substrate includes at least one selected from aluminum, aluminum alloy, magnesium, and magnesium alloy substrates. The metal substrate can be selected according to actual needs.

[0038] A second aspect of this application is to provide a method for preparing the aforementioned metal part, comprising the following steps:

[0039] The metal substrate is placed in an electrolyte for micro-arc oxidation;

[0040] The electrolyte comprises zirconium salt, organic acid, fluoride and hydrogen peroxide, and the pH of the electrolyte is less than 6.5.

[0041] The voltage for the micro-arc oxidation is 300-640V.

[0042] In the preparation method provided in this application, the pH of the electrolyte is less than 6.5, and a voltage of 300-640V is used to perform micro-arc oxidation on the metal substrate. Under the above conditions, the zirconium ions in the electrolyte system form electronegative complexes with acid radicals and fluoride ions, forming an oxide film during oxidation. This oxide film has a high breakdown voltage and high energy during oxidation, causing the oxide film to form molten oxide. The molten oxide is "sprayed" outward, then cools and solidifies to form a synaptic structure, ultimately forming a hydrophobic layer with uniform thickness on the surface of the metal part, consisting of a coral-like structure and / or a network structure formed by multiple interconnected synaptic structures. Zirconium ions in the solution combine with hydroxide ions on the surface of the oxide film to form zirconium hydroxide, and further lose water during the breakdown melting process to form zirconium oxide. Therefore, the main component of the hydrophobic layer is zirconium oxide, which is white, giving the hydrophobic layer a white appearance. Thus, the hydrophobic layer of this application can both improve the hydrophobicity of the metal part and enhance its surface decorative effect.

[0043] In some embodiments, to further improve the hydrophobicity of the metal part, the micro-arc oxidized metal substrate is further subjected to organic modification treatment. Specifically, the organic modification treatment includes: immersing the micro-arc oxidized metal substrate in AF anti-fingerprint solution (a composition of active silane groups and fluorine-modified organic groups) for modification. For example, AF anti-fingerprint solution can be at least one of Dongxing J04003, Dongxing J0800, Zhongfu LK06, or Boshi BOS05. The hydrophobic layer has a coral-like structure and / or a network structure formed by multiple interconnected synaptic structures, which can reduce the contact between the liquid and the surface; organic modification can reduce the surface energy of the hydrophobic layer, thereby achieving a superhydrophobic effect.

[0044] In some embodiments, the frequency of the micro-arc oxidation is 200-3000 Hz, and the duration of the micro-arc oxidation is 5-120 min. To further control the uniformity of the hydrophobic layer thickness, preferably, the frequency of the micro-arc oxidation is 500-2400 Hz, and the duration of the micro-arc oxidation is 20-80 min.

[0045] In some embodiments, the temperature of the electrolyte is controlled at 10-30°C, which is conducive to the formation of a hydrophobic layer.

[0046] In some embodiments, the electrolyte comprises the following components by weight: 2-40 g / L zirconium salt, 0.5-10 g / L organic acid, 0.5-5 g / L fluoride, and 0.1-10 g / L hydrogen peroxide.

[0047] Specifically, the zirconium salt includes at least one of zirconium acetate, zirconium carbonate, and potassium fluorozirconate; the organic acid includes at least one of oxalic acid, citric acid, and tartaric acid; and the fluoride includes at least one of sodium fluoride, potassium fluoride, and hydrofluoric acid.

[0048] In some embodiments, the electrolyte further includes a pH adjuster. The pH adjuster may be at least one selected from acetic acid, sodium acetate, boric acid, and sodium borate.

[0049] In some embodiments, the metal substrate is degreased, acid-etched, and neutralized before the micro-arc oxidation process. This pretreatment improves the smoothness and cleanliness of the metal substrate surface, which is beneficial for subsequent micro-arc oxidation operations.

[0050] The present application will be described in detail below through embodiments, but the present application is not limited to the following embodiments.

[0051] Example 1

[0052] This embodiment illustrates the metal part and its preparation method disclosed in this application, including the following steps:

[0053] Pretreatment: The aluminum alloy is treated with processes such as degreasing, acid etching, and neutralization.

[0054] Micro-arc oxidation: The pretreated aluminum alloy is immersed in an electrolyte for oxidation. The electrical parameters are: voltage 320V, frequency 1200HZ, and oxidation time 40min. The electrolyte contains: 4g / L potassium fluorozirconate, 0.5g / L oxalic acid, 1g / L potassium fluoride, and 0.1g / L hydrogen peroxide, and the pH is adjusted to 4.5 with acetic acid. The oxidation temperature is 20℃.

[0055] Organic modification: The micro-arc oxidized aluminum alloy was immersed in AF anti-fingerprint liquid (Dongxing J04003) for 3 minutes to finally obtain metal part S1.

[0056] Example 2

[0057] This embodiment illustrates the metal part and its preparation method disclosed in this application, including the following steps:

[0058] Pretreatment: The aluminum alloy is treated with processes such as degreasing, acid etching, and neutralization.

[0059] Micro-arc oxidation: The pretreated aluminum alloy is immersed in an electrolyte for oxidation. The electrical parameters are: voltage 480V, frequency 200HZ, and oxidation time 40min. The electrolyte contains: 8g / L potassium fluorozirconate, 1g / L oxalic acid, 2g / L potassium fluoride, and 0.1g / L hydrogen peroxide, and the pH is adjusted to 4.5 with acetic acid. The oxidation temperature is 20℃.

[0060] Organic modification: The micro-arc oxidized aluminum alloy was immersed in AF anti-fingerprint liquid (Dongxing J04003) for 3 minutes to obtain the metal part S2.

[0061] Example 3

[0062] This embodiment illustrates the metal part and its preparation method disclosed in this application, including the following steps:

[0063] Pretreatment: The aluminum alloy is treated with processes such as degreasing, acid etching, and neutralization.

[0064] Micro-arc oxidation: The pretreated aluminum alloy is immersed in an electrolyte for oxidation. The electrical parameters are: voltage 620V, frequency 2500HZ, and oxidation time 40min. The electrolyte contains: 20g / L potassium fluorozirconate, 5g / L oxalic acid, 2g / L potassium fluoride, and 2g / L hydrogen peroxide, and the pH is adjusted to 3.2 with acetic acid. The oxidation temperature is 20℃.

[0065] Organic modification: The micro-arc oxidized aluminum alloy was immersed in AF anti-fingerprint liquid (Dongxing J04003) for 3 minutes to finally obtain metal part S3.

[0066] Example 4

[0067] This embodiment illustrates the metal part and its preparation method disclosed in this application, including the following steps:

[0068] Pretreatment: The aluminum alloy is treated with processes such as degreasing, acid etching, and neutralization.

[0069] Micro-arc oxidation: The pretreated aluminum alloy is immersed in an electrolyte for oxidation. The electrical parameters are: voltage 380V, frequency 200HZ, and oxidation time 40min. The electrolyte contains: 40g / L potassium fluorozirconate, 8g / L oxalic acid, 2g / L potassium fluoride, and 8g / L hydrogen peroxide, and the pH is adjusted to 2.4 with acetic acid. The oxidation temperature is 20℃.

[0070] Organic modification: The micro-arc oxidized aluminum alloy was immersed in AF anti-fingerprint liquid (Dongxing J04003) for 3 minutes to finally obtain metal part S4.

[0071] Example 5

[0072] This embodiment illustrates the metal part and its preparation method disclosed in this application, including the following steps:

[0073] Pretreatment: The aluminum alloy is treated with processes such as degreasing, acid etching, and neutralization.

[0074] Micro-arc oxidation: The pretreated aluminum alloy is immersed in an electrolyte for oxidation. The electrical parameters are: voltage 480V, frequency 200HZ, and oxidation time 40min. The electrolyte contains: 50g / L potassium fluorozirconate, 8g / L oxalic acid, 2g / L potassium fluoride, and 8g / L hydrogen peroxide, and the pH is adjusted to 4.5 with acetic acid. The oxidation temperature is 20℃.

[0075] Organic modification: The micro-arc oxidized aluminum alloy was immersed in AF anti-fingerprint liquid (Dongxing J04003) for 3 minutes to finally obtain metal part S5.

[0076] Comparative Example 1

[0077] This comparative example includes the following steps:

[0078] Pretreatment: The aluminum alloy is treated with processes such as degreasing, acid etching, and neutralization.

[0079] Micro-arc oxidation: The pretreated aluminum alloy is immersed in an electrolyte for oxidation. The electrical parameters are: voltage 320V, frequency 1200HZ, and oxidation time 40min. The alkaline electrolyte contains: 20g / L sodium hexametaphosphate, 8g / L sodium silicate, 4g / L potassium fluoride, and 1g / L potassium hydroxide. The oxidation temperature is 20℃.

[0080] Organic modification: The micro-arc oxidized aluminum alloy was immersed in AF anti-fingerprint liquid (Dongxing J04003) for 3 minutes to obtain the metal part D1.

[0081] Comparative Example 2

[0082] This comparative example includes the following steps:

[0083] Pretreatment: The aluminum alloy is treated with processes such as degreasing, acid etching, and neutralization.

[0084] Micro-arc oxidation: The pretreated aluminum alloy is immersed in an electrolyte for oxidation. The electrical parameters are: voltage 480V, frequency 200HZ, and oxidation time 40min. The alkaline electrolyte contains: 20g / L sodium hexametaphosphate, 8g / L sodium silicate, 2g / L sodium citrate, and 2g / L potassium fluorozirconate. The oxidation temperature is 20℃.

[0085] Organic modification: The micro-arc oxidized aluminum alloy was immersed in AF anti-fingerprint liquid (Dongxing J04003) for 3 minutes to obtain the metal part D2.

[0086] Comparative Example 3

[0087] The difference between this comparative example and Example 1 is that the voltage for micro-arc oxidation is 250V, while the other parameters and processes are the same as in Example 1, ultimately yielding metal part D3.

[0088] Performance testing

[0089] Appearance: Using a D65 light source, visually inspect the appearance of the metal parts from the same position.

[0090] Roughness: The roughness of the metal parts was tested using a roughness tester (instrument model: Surtronic 25).

[0091] Film thickness: The film thickness of the metal parts was tested using metallographic methods (1. Taking sample cross-sections using an IsoMet5000 precision linear cutter; 2. Mounting the sample using a PHOENIX4000 vacuum mounting machine; 3. Measuring the film thickness using a metallographic microscope AX10 / magerA1M).

[0092] Water droplet angle: The water droplet angle of the metal parts is tested using a water droplet angle tester (instrument model: SDC-200S).

[0093] Salt spray test:

[0094] 1. Salt concentration: 5%, test temperature: 35℃, spray solution pH (35℃): pH 6.5-7.2. Spray pressure: 0.07-0.17 MPa. Spray method: continuous spraying, spray volume: 1.5±0.5 kg / hr (funnel area 80 cm²). 2 ) ;

[0095] 2. Metal sample placement method: Place the sample face up, and after 48 hours, add a coated section to all segments and perform a 2mm X-cutting test. If the sample surface shows no corrosion, discoloration, or film peeling, it is considered OK; otherwise, it is NG.

[0096] Boiling test:

[0097] 1. Constant temperature water bath, temperature / time: 80℃±2℃, 30min;

[0098] 2. Soak the metal test piece in a constant temperature water bath for 30 minutes, then wipe off the moisture with a cloth, and then place it at room temperature for 4 hours.

[0099] 3. Draw a checkerboard pattern on the test piece at 2mm intervals, then attach a tape and pull it vertically with strong force once. If the sample surface shows no corrosion or discoloration, and the film layer does not peel off, it is considered OK; otherwise, it is NG.

[0100] SEM test

[0101] The surface microstructure of the metal samples from Example 1 and Comparative Example 1 was characterized using a scanning electron microscope (model: LYRA3 XMH). The resulting electron microscope images with a scale bar of 10 μm are shown below. Figure 1 and Figure 2 As shown. In Embodiment 1 of this application, the surface of the hydrophobic layer of the metal part has tiny, coral-like microscopic protrusions, while in Comparative Example 1, the surface of the film layer has pores similar to those of a volcanic eruption, and the structure of this application cannot be obtained.

[0102] Table 1

[0103]

[0104] As can be seen from the embodiments and comparative examples, the metal parts provided in this application have excellent hydrophobicity, with a water droplet angle greater than 150 degrees, and good adhesion between the film layer and the metal substrate, resulting in a good appearance. The water droplet angles of the metal parts in the comparative examples are all less than 150 degrees, indicating poor hydrophobicity.

[0105] The preferred embodiments of this application have been described in detail above. However, this application is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, and these simple modifications all fall within the protection scope of this application.

[0106] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this application will not describe the various possible combinations separately.

[0107] Furthermore, various different implementations of this application can be combined in any way, as long as they do not violate the spirit of this application, they should also be regarded as the content disclosed in this application.

Claims

1. A metal part, characterized in that, The invention includes a metal substrate and a hydrophobic layer located on at least a portion of the surface of the metal substrate, wherein the main component of the hydrophobic layer contains zirconium oxide, and the hydrophobic layer has a coral-like structure and / or a mesh structure. The metal substrate includes at least one of aluminum, aluminum alloy, magnesium, and magnesium alloy substrate; The method for preparing the metal part includes the following steps: The metal substrate is placed in an electrolyte for micro-arc oxidation; The electrolyte comprises zirconium salt, organic acid, fluoride and hydrogen peroxide, and the pH of the electrolyte is less than 6.

5. The voltage for the micro-arc oxidation is 300-640V.

2. The metal part according to claim 1, characterized in that, The hydrophobic layer contains at least 50 wt% zirconium oxide.

3. The metal part according to claim 1, characterized in that, The thickness of the hydrophobic layer is 5-30µm.

4. The metal part according to claim 1, characterized in that, The water droplet angle of the hydrophobic layer is greater than 150 degrees.

5. The metal part according to claim 1, characterized in that, The hydrophobic layer has a coating layer formed on the surface away from the metal substrate.

6. The metal part according to claim 1, characterized in that, The method for preparing the metal part further includes organic modification of the metal substrate after micro-arc oxidation; the hydrophobic layer contains an organic compound containing fluorine (F).

7. The metal part according to claim 6, characterized in that, The organic modification process includes: immersing the micro-arc oxidized metal substrate in AF anti-fingerprint solution for modification.

8. The metal part according to claim 1, characterized in that, The frequency of the micro-arc oxidation is 200-3000Hz, and the duration of the micro-arc oxidation is 5-120min.

9. The metal part according to claim 1, characterized in that, The temperature of the electrolyte is controlled between 10-30℃.

10. The metal part according to claim 1, characterized in that, The electrolyte comprises the following components by weight: 2-40 g / L zirconium salt, 0.5-10 g / L organic acid, 0.5-5 g / L fluoride, 0.1-10 g / L hydrogen peroxide.

11. The metal part according to claim 1, characterized in that, The zirconium salt includes at least one of zirconium acetate, zirconium carbonate, and potassium fluorozirconate.

12. The metal part according to claim 1, characterized in that, The organic acid includes at least one of oxalic acid, citric acid, and tartaric acid.

13. The metal part according to claim 1, characterized in that, The fluoride includes at least one of sodium fluoride, potassium fluoride, and hydrofluoric acid.

14. The metal part according to claim 1, characterized in that, The electrolyte also includes a pH adjuster.

15. The metal part according to claim 1, characterized in that, Before performing the micro-arc oxidation, the metal substrate is subjected to degreasing, acid etching, and neutralization treatment.

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