Metal part, surface treatment method and electronic equipment

Abstract

The invention provides a metal piece. The metal piece comprises a base material; the anodic oxidation layer is located on the surface of the base material, the anodic oxidation layer has a basic color, and the interior of the anodic oxidation layer is of a porous structure; the laminated film is positioned in the hole of the anodic oxide layer; the laminated film comprises first film layers and second film layers which are alternately arranged, the refractive index of the first film layers is lower than that of the second film layers, and the laminated film is suitable for reducing reflection of the anodic oxide layer, so that the color presented by the metal piece and the basic color meet the approximate preset condition. The invention further provides a surface treatment method of the metal part and electronic equipment.

Description

Technical Field

[0001] The present disclosure relates to a metal part, a surface treatment method, and an electronic device. Background Art

[0002] With the development of technology, users have higher and higher requirements for the appearance quality of metal devices.

[0003] To improve the surface quality of metals, taking aluminum alloy as an example, the surface treatment of aluminum alloy in related technologies includes first performing a wire drawing process and then anodizing; or first performing a sandblasting process and then anodizing; and directly anodizing the aluminum alloy sheet.

[0004] However, the surface quality of the above-treated metals is poor and it is difficult to meet the requirements of users for appearance quality. Summary of the Invention

[0005] One aspect of the present disclosure provides a metal part, including: a substrate; an anodic oxidation layer located on the surface of the substrate, the anodic oxidation layer having a base color and a porous structure inside; a stacked film located in the pores of the anodic oxidation layer; the stacked film is an alternately arranged first film layer and second film layer, the refractive index of the first film layer is lower than that of the second film layer, and the stacked film is suitable for reducing the reflection of the anodic oxidation layer so that the color presented by the metal part and the base color meet a preset condition of being close.

[0006] Optionally, the total thickness of the above-mentioned stacked film is lower than the surface roughness of the substrate.

[0007] Optionally, the above-mentioned metal part is an aluminum alloy part.

[0008] Optionally, the above-mentioned base color is black.

[0009] Optionally, the color difference value of the above-mentioned metal part is ≤4.

[0010] Optionally, the surface roughness of the above-mentioned substrate is 0.7 - 0.9 μm.

[0011] Optionally, the total thickness of the above-mentioned stacked film is 460 - 480 nm.

[0012] Optionally, the thickness of the anodic oxidation layer is 12 - 16 μm.

[0013] Optionally, the above-mentioned metal part further includes: a base film located in the pores of the anodic oxidation layer and under the stacked film.

[0014] Optionally, the thickness of the base film is 20 - 40 nm.

[0015] Optionally, the above-mentioned metal part further includes: a protective layer located on the surface of the anodic oxidation layer away from the substrate.

[0016] Optionally, the thickness of the protective layer is 90 to 110 nm.

[0017] Optionally, the first film layer is silicon dioxide and the second film layer is niobium pentoxide.

[0018] Optionally, taking an alternating layer composed of one first film layer and one second film layer as a period, the number of stacking periods of the stacked film is 4.

[0019] Another aspect of the present disclosure provides a surface treatment method for a metal part, including: successively performing anodic oxidation and color adjustment treatment on the substrate of the metal part to obtain a metal part with an anodic oxidation layer on its surface, the anodic oxidation layer having a base color and a porous structure; performing a first coating treatment on the surface of the metal part by magnetron sputtering, alternately depositing a first film layer and a second film layer in the pores of the anodic oxidation layer to obtain a metal part with a stacked film on its surface; performing heat treatment on the surface of the metal part with the stacked film on its surface, and the heat treatment is carried out under the action of a sealing agent to seal the porous structure of the anodic oxidation layer to obtain a surface-treated metal part; the refractive index of the first film layer is lower than that of the second film layer, and the stacked film is suitable for reducing the reflection of the anodic oxidation layer so that the color presented by the metal part and the base color satisfy a close preset condition.

[0020] Optionally, before performing the first coating treatment, it further includes: performing a second coating treatment on the surface of the anodic oxidation layer of the metal part by magnetron sputtering, and depositing a base film in the pores of the anodic oxidation layer of the metal part.

[0021] Optionally, the material of the base film is a metal oxide, and the thickness of the base film is 20 to 40 nm.

[0022] Another aspect of the present disclosure provides an electronic device, including a housing, at least part of the housing is formed by a metal part, and the metal part includes: a substrate; an anodic oxidation layer located on the surface of the substrate, the anodic oxidation layer having a base color and a porous structure inside; a stacked film located in the pores of the anodic oxidation layer; the stacked film is an alternately arranged first film layer and second film layer, the refractive index of the first film layer is lower than that of the second film layer, and the stacked film is suitable for reducing the reflection of the anodic oxidation layer so that the color presented by the metal part and the base color satisfy a close preset condition. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] To more fully understand the present disclosure and its advantages, reference will now be made to the following description in conjunction with the accompanying drawings, where:

[0024] Figure 1 Shows a schematic structural diagram of a metal part according to an embodiment of the present disclosure;

[0025] Figure 2Shows the schematic diagram of antireflection of the laminated film according to an embodiment of the present disclosure;

[0026] Figure 3 Shows the flowchart of the surface treatment method of the metal part according to an embodiment of the present disclosure;

[0027] Figure 4 Shows the physical diagram of the aluminum alloy part after surface treatment in Embodiment 1 of the present disclosure;

[0028] Figure 5 Shows the physical diagram of the aluminum alloy part after surface treatment in Comparative Example 1 of the present disclosure;

[0029] Figure 6 Shows the physical diagrams of the aluminum alloy parts after surface treatment in Embodiment 1 and Comparative Example 3 of the present disclosure.

[0030] In the said drawings, the reference numerals are as follows:

[0031] 1 - Anodic oxidation layer;

[0032] 2 - Laminated film;

[0033] 3 - Protective layer;

[0034] 4 - Base film. Detailed implementation manners

[0035] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present disclosure.

[0036] The terms used herein are merely for describing specific embodiments and are not intended to limit the present disclosure. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0037] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0038] In the related art, methods such as the combination of sandblasting and anodizing, the combination of polishing and spraying matte paint, and micro-arc oxidation can be used to improve the surface properties and appearance of metal parts. After anodizing, the surface substance reflects light, making the basic color of the metal part appear white. Spraying matte paint makes the color of the metal part appear white due to refraction, while micro-arc oxidation makes the basic color of the metal part appear poorly. The above situations all affect the surface quality of the metal part.

[0039] In the process of implementing the present disclosure, it is found that the diffuse reflection of the rough surface can be combined with the deposition of a stacked film in the pores of the anodic oxidation layer to reduce the reflection of light, thereby improving the surface quality of the metal part.

[0040] In view of this, one aspect of the present disclosure provides a metal part. Figure 1 The structural schematic diagram of the metal part according to an embodiment of the present disclosure is shown. As Figure 1 shown, the metal part includes: a substrate (not shown in the figure), an anodic oxidation layer 1, and a stacked film 2.

[0041] The substrate, as the main body part of the metal part, is composed of a metal material and provides a basic support for the subsequent surface treatment layer. The anodic oxidation layer 1 is located on the surface of the substrate and is formed on the substrate surface through an anodizing process. The anodic oxidation layer 1 has a basic color, for example, it can be color-matched after the conventional anodizing process to form the desired color. Due to the influence of the formation process, the anodic oxidation layer 1 has a porous structure inside, for example, micron-level or nano-level pores can be uniformly or non-uniformly distributed, providing a structural basis for the subsequent filling of the stacked film.

[0042] The stacked film 2 can be deposited in the pores of the anodic oxidation layer 1 by physical or chemical deposition methods. The stacked film 2 is composed of two film layers with different refractive indices stacked alternately, and the refractive index of the first film layer is lower than that of the second film layer. Through the alternating arrangement of the two film layers, the formed stacked film 2 has an optical interference structure, and multiple reflections and refractions occur at the interfaces inside the pores of the anodic oxidation layer 1. Figure 2 The anti-reflection principle diagram of the stacked film according to an embodiment of the present disclosure is shown. As Figure 2 shown, through the setting of the stacked film 2, it helps to reduce the reflection of the anodic oxidation layer 1, making the reflection optical path of the reflected light change at different interfaces inside the pores, so that the reflected lights cancel each other out, thereby achieving the reduction of the light reflectance and the increase of the transmittance, and further making the color presented by the metal part satisfy a close preset condition with the basic color.

[0043] It can be understood that the close preset condition can be that the color difference between the presented color and the basic color ≤ 10. The color difference can be understood as a numerical index that quantifies the visual difference between the presented color and the basic color.

[0044] According to an embodiment of the present disclosure, by depositing the laminated film 2 in the pores of the anodic oxidation layer 1, an optical interference structure formed by the different refractive indices of the two film layers in the laminated film 2 causes the optical path difference of the reflected light at different interfaces at the pores to change. As a result, the reflected light cancels each other out, reducing the reflection of light and increasing the transmission of light, making the color presented by the metal part closer to the base color under the antireflection and transmission enhancement effects of the laminated film 2.

[0045] In addition, through the sealing treatment of the anodic oxidation layer 1, the surface of the anodic oxidation layer 1 away from the substrate has high corrosion resistance and wear resistance, and the surface is flat and smooth, which is beneficial to obtaining better surface quality.

[0046] In some embodiments of the present disclosure, the absolute value of the difference between the refractive index of the first film layer and the refractive index of the second film layer is greater than or equal to 0.5. Based on the relatively large absolute value of the refractive index difference, the laminated film 2 composed of the above film layers can better exert the interference effect of light, thereby achieving a better antireflection and transmission enhancement effect, and making the metal part have better surface quality.

[0047] In some embodiments of the present disclosure, the metal part can be any workpiece, and those skilled in the art can select a suitable metal part according to actual needs. Exemplarily, the metal part can be a workpiece obtained by processes such as turning, grinding, polishing, and sandblasting. The surface of the metal part can have a certain roughness. The roughness R a can be understood as the degree of unevenness on the surface of the metal part below the millimeter scale.

[0048] In some embodiments of the present disclosure, the metal part is an aluminum alloy part. Taking the aluminum alloy part as an example, it is immersed in an acidic electrolyte as the anode, and a porous alumina layer (anodic oxidation layer 1) is obtained by applying a voltage. The formation of the porous structure provides space for the subsequent deposition of the laminated film 2. The total thickness of the laminated film 2 can be lower than the roughness of the substrate surface to prevent the laminated film 2 from overflowing outside the pores of the anodic oxidation layer 1, thereby further changing the optical path difference of the reflected light to achieve the antireflection and transmission enhancement effect on light.

[0049] In some embodiments of the present disclosure, the roughness R of the substrate surface a is 0.7 - 0.9 μm. When the roughness is too large, too much mutual cancellation of light occurs, resulting in a certain color deviation between the color presentation effect of the metal part and the base color; when the roughness is too small, more light is reflected, making the color presented by the metal part appear white and the color rendering is poor. When the roughness of the substrate surface is within the above range, the diffuse reflection effect on light is better, enabling the metal part to better restore the base color.

[0050] Exemplarily, the roughness R of the substrate surface aIt can be 0.7μm, 0.75μm, 0.8μm, 0.85μm or 0.9μm, or a range formed between any two of these values.

[0051] Optionally, the surface roughness R of the substrate a can be 0.8μm. At this time, the diffuse reflection effect of light is better, and the color presented by the metal part can better restore the color of the base color.

[0052] In some embodiments of the present disclosure, the total thickness of the laminated film 2 is less than 0.9μm. When the total thickness of the laminated film 2 is too thick, the laminated film may overflow the holes, resulting in a weak effect of reducing light reflection, and color deviation may occur, causing the color presented by the metal part to be distorted.

[0053] Exemplarily, the total thickness of the laminated film 2 can be, for example, 0.2μm, 0.4μm, 0.6μm, 0.8μm, etc., or a range formed between any two of these values.

[0054] Optionally, the total thickness of the laminated film 2 is greater than 0.2μm and less than 0.9μm to present a better anti-reflection and light-transmission increasing effect for light; when the total thickness of the laminated film is too thin, the number of laminated cycles of the laminated film deposited in the holes is small, and it is difficult to form an anti-reflection and light-transmission increasing effect for light, resulting in the color presented by the metal part being white, with a large difference from the base color.

[0055] In some embodiments of the present disclosure, the base color is black. It can be understood that the color difference at this time is L, which can be understood as lightness, and its value range is 0 to 100. The lower the value of the color difference L, the closer it is to black. For example, when the color difference L is 0, it represents absolute black. When considering the color presentation effect, sometimes two parameters a and b are also considered. Among them, a represents the offset of the color in the red-green direction, and b represents the offset of the color in the yellow-blue direction. The color difference L of the metal part is ≤4. It can be understood that when the value of L is close to 0, it means that the presentation effect of the metal part for black is very close to the base color of the anodic oxide layer 1.

[0056] Exemplarily, the color difference L of the metal part can be, for example, 0.5, 1, 1.5, 2, 2.5, 3, 3.2, 3.5, 3.6 or 4, etc., or a range formed between any two of these values.

[0057] In some embodiments of the present disclosure, the total thickness of the laminated film 2 is 460 - 480nm; adjusting the thickness of the laminated film 2 within the above range helps to provide better stability, provides space for subsequent heat treatment to seal the porous structure of the anodic oxide layer 1, and at the same time takes into account a better anti-reflection and light-transmission increasing effect, making the color presented by the metal part closer to the base color.

[0058] Exemplarily, the total thickness of the laminated film 2 can be, for example, 460 nm, 470 nm, or 480 nm, or a range formed between any two of these values.

[0059] In some embodiments of the present disclosure, the thickness of the anodic oxidation layer 1 is 12 - 16 μm. Such a setting helps to form a dense barrier layer (0.1 μm) and a suitable porous structure layer. The barrier layer can block the erosion of water vapor, chloride ions, etc. in the environmental medium on the aluminum alloy substrate. Moreover, the anodic oxidation layer 1 with the above thickness can significantly improve the wear resistance of the metal part surface. At the same time, the above thickness is beneficial to providing a better hole loading capacity, which helps to accommodate the deposition of multiple layers of laminated films subsequently, and avoids performance unevenness or film layer rupture caused by too thin film layers.

[0060] Exemplarily, the thickness of the anodic oxidation layer 1 can be, for example, 12 μm, 13 μm, 14 μm, 15 μm, or 16 μm, or a range formed between any two of these values.

[0061] In some embodiments of the present disclosure, the metal part further includes: a base film 4, which is located in the holes of the anodic oxidation layer 1 and under the laminated film 2. The base film 4 is suitable for improving the adhesion between the laminated film 2 and the anodic oxidation layer 1, thereby improving the stability of the laminated film 2 and providing a stable guarantee for the color display of the metal part.

[0062] In some embodiments of the present disclosure, the material of the base film 4 is a metal oxide, for example, it can be alumina. The thickness of the base film 4 is 20 - 40 nm. Such a setting can enable the laminated film 2 to adhere more stably in the holes of the anodic oxidation layer 1.

[0063] In some embodiments of the present disclosure, the metal part further includes: a protective layer 3. The protective layer 3 is located on the surface of the anodic oxidation layer 1 away from the substrate. The protective layer 3 can be formed, for example, by fluoropolymer spraying, which further improves the surface quality of the metal part, such as improving smoothness and anti-fingerprint effect. It can be understood that when the basic color of the metal part is black, due to the high color saturation, under the action of the protective layer 3, the color change caused by touching can be further reduced, and the surface texture of the metal part can be improved.

[0064] In some embodiments of the present disclosure, the thickness of the protective layer 3 is 90 - 110 nm, for example, it can be 90 nm, 100 nm, 110 nm, or a range formed between any two of these values.

[0065] In some embodiments of the present disclosure, the first film layer is silicon dioxide, and the second film layer is niobium pentoxide. The refractive index of the first film layer is relatively low, about 1.45, and the refractive index of the second film layer is relatively high, about 2.3. The large refractive index difference between the two enables the interference effect on light to be better exerted in the stacked film 2. The high-refractive-index niobium pentoxide and the low-refractive-index silicon dioxide film layers are alternately arranged, causing the optical path difference of the reflected light at the interfaces of different film layers in the holes to change, and the reflected lights cancel each other out, thereby reducing the reflection effect of light and increasing the transmission effect of light.

[0066] It should be noted that during the screening process of the stacked film 2, it is found that not all film layer structures with alternately arranged high and low refractive indices can exhibit a small color difference. For example, when using some other high-refractive-index thin films to form an alternating structure with silicon dioxide, the cancellation effect of the light reflection effect is not obvious, resulting in a large color difference, and it is thus difficult to achieve a high-saturation black presentation effect.

[0067] In some embodiments of the present disclosure, taking an alternating layer composed of one layer of the first film layer and one layer of the second film layer as a period, the number of stacked periods of the stacked film 2 can be 4. When the number of periods of the stacked film 2 is too small, the anti-reflection and light-transmission-increasing effects are not obvious, resulting in a poor presentation effect of the base color; when the number of stacked film periods is too large, the stacked film is too thick, with poor stability, and color deviation occurs. When observing the metal part from different angles, it has different colors, making the surface presentation effect unstable.

[0068] Another aspect of the present disclosure provides a surface treatment method for a metal part. Figure 3 The flowchart of the surface treatment method for the metal part according to the embodiments of the present disclosure is shown, as Figure 3 shown, and this surface treatment method includes operations S301 to S303.

[0069] In operation S301, the base material of the metal part is successively subjected to anodic oxidation and color adjustment treatment to obtain a metal part with an anodic oxide layer 1 on the surface. The anodic oxide layer 1 has a base color and a porous structure.

[0070] In this embodiment, a porous anodic oxide layer 1 is formed on the surface of the aluminum alloy base material by anodic oxidation. The method of anodic oxidation is the same as the foregoing and will not be elaborated here. The color adjustment treatment can be, for example, by chemical staining or electrolytic coloring to endow the anodic oxide layer 1 with a base color (such as a color with a relatively high saturation like black). The presentation of the base color comes from dyes adsorbed in the holes. Among them, the porous structure serves as a nanoscale template for the subsequent deposition of the stacked film 2, and the base color provides the background color for the subsequent optical interference.

[0071] In operation S302, the surface of the metal part is subjected to a first coating treatment by magnetron sputtering, and the first film layer and the second film layer are alternately deposited in the pores of the anodic oxidation layer 1 to obtain a metal part with a laminated film 2 on its surface.

[0072] In this embodiment, by depositing two film layers with different refractive indices, most of the reflected light is selectively cancelled out through the optical interference effect between the different refractive indices, making the color closer to the base color, thereby avoiding the whitening phenomenon caused by the high reflectivity of the metal itself. The number of cycles of film layer alternation can be, for example, between 3 and 7. Too many may cause pore blockage, and too few may make it difficult to form an effect of cancelling out the reflected light.

[0073] In operation S303, the surface of the metal part with the laminated film 2 on its surface is heat-treated. The heat treatment is carried out under the action of a sealing agent to seal the porous structure of the anodic oxidation layer 1, obtaining the surface-treated metal part.

[0074] In this embodiment, the heat treatment is carried out in the presence of a sealing agent. The sealing agent can be, for example, a nickel salt or a silicate. Taking the nickel salt as an example, nickel hydroxide is hydrolyzed to block the pores, and the heat treatment promotes the formation of a stable chemical bond (such as silicon-oxygen-aluminum) between the laminated film 2 and the anodic oxidation layer 1. Heat treatment sealing helps prevent moisture or oxygen in the environmental medium from invading the pores, resulting in corrosion or peeling of the laminated film 2, and also improves the hardness and wear resistance of the surface of the anodic oxidation layer 1, enhancing the smoothness; at the same time, it also improves the optical stability, enabling the metal part to stably present a high-saturation base color.

[0075] According to the embodiments of the present disclosure, the refractive index of the first film layer is lower than that of the second film layer, and the laminated film 2 is suitable for reducing the reflection of the anodic oxidation layer 1 so that the color presented by the metal part meets a preset condition close to the base color. The preset condition here is the same as the foregoing content and will not be elaborated herein. Through the above surface treatment operations, the present disclosure improves the color presentation effect on the surface of the metal part, making the presented color closer to the base color and increasing the saturation of the presented color. And due to the sealing treatment, the surface of the metal part has good durability, and still presents a good color performance after repeated friction. It helps to be subsequently applied to technical fields such as mobile phone casings, automotive decorations, or instrument casings.

[0076] It can be understood that the parameters such as the roughness of the substrate surface, the material and thickness of the laminated film 2, the base color, the color difference value of the metal part, the anodic oxidation layer 1, the protective layer 3, etc. are the same as the foregoing and will not be elaborated one by one herein.

[0077] In some embodiments of the present disclosure, before anodization, the metal part can be sandblasted as needed to adjust the surface roughness of the metal part substrate to be between 0.7 and 0.9 μm, thereby improving the diffuse reflection effect of light. The diffuse reflection makes the light evenly disperse in all directions, greatly reducing the intensity of direct reflection, and thus reducing the brightness of the substrate surface. It interacts with the optical interference of the subsequent formed laminated film 2, so that when the light passes through the laminated film 2, the propagation direction changes, so that the light that might have been reflected out is redirected and dispersed, thereby reducing the reflectivity, improving the transmittance, and further improving the color rendering effect of the base color. The sandblasting treatment can use zircon sand, etc., and is not particularly limited herein.

[0078] In some embodiments of the present disclosure, the anodization method can be carried out, for example, in a conventional manner by successively passing through degreasing, alkali etching, neutralization, polishing, etc. Since it is not the focus of the present disclosure, it will not be described in detail herein.

[0079] In some embodiments of the present disclosure, the first coating treatment can be carried out, for example, by magnetron sputtering to deposit the first film layer and the second film layer in sequence. Coating parameters: the power of magnetron sputtering is 160 - 240 W, the working gas pressure is 0.1 - 0.9 Pa, the working gas is argon, the reaction gas is oxygen, and the temperature of the substrate is 150 °C.

[0080] In some embodiments of the present disclosure, the heat treatment temperature is 93 - 100 °C, and the heat treatment time is 20 - 40 min.

[0081] In some embodiments of the present disclosure, before operation S302, it further includes: performing a second coating treatment on the surface of the anodized layer 1 of the metal part by magnetron sputtering to deposit the base film 4 in the pores of the anodized layer 1 of the metal part. Forming the base film 4 helps to improve the adhesion between the overall laminated film 2 and the anodized layer 1, improve the stability of the laminated film 2, and further improve the stability of the color presented on the surface.

[0082] In some embodiments of the present disclosure, the material of the base film 4 is a metal oxide, such as alumina. The thickness of the base film 4 is 20 - 40 nm. Such a setting can enable the laminated film 2 to adhere more stably in the pores of the anodized layer 1.

[0083] Exemplarily, the thickness of the base film 4 can be, for example, 20 nm, 30 nm, 40 nm, etc., or a range composed of any two of the above values.

[0084] Another aspect of the present disclosure provides an electronic device, including a housing, at least a part of the housing is formed by a metal member, and the metal member includes: a substrate, an anodic oxidation layer 1, and a laminated film 2. The anodic oxidation layer 1 is located on the surface of the substrate, the anodic oxidation layer 1 has a base color, and the interior of the anodic oxidation layer 1 has a porous structure; the laminated film 2 is located in the pores of the anodic oxidation layer 1; the laminated film 2 is an alternating arrangement of a first film layer and a second film layer, the refractive index of the first film layer is lower than that of the second film layer, and the laminated film 2 is adapted to reduce the reflection of the anodic oxidation layer 1, so that the color presented by the metal member and the base color meet a preset condition of being close.

[0085] In some embodiments of the present disclosure, a component of the housing is formed by the aforementioned metal member.

[0086] In some embodiments of the present disclosure, the total thickness of the laminated film 2 is lower than the surface roughness of the substrate; the metal member is an aluminum alloy member.

[0087] In some embodiments of the present disclosure, the base color is black; the color difference value of the metal member is ≤4.

[0088] In some embodiments of the present disclosure, the surface roughness of the substrate is 0.7~0.9μm.

[0089] In some embodiments of the present disclosure, the total thickness of the laminated film 2 is 460~480nm; the thickness of the anodic oxidation layer 1 is 12~16μm.

[0090] In some embodiments of the present disclosure, the metal member further includes: a base film 4, located in the pores of the anodic oxidation layer 1 and below the laminated film 2.

[0091] In some embodiments of the present disclosure, the thickness of the base film is 20~40nm.

[0092] In some embodiments of the present disclosure, the metal member further includes: a protective layer 3, located on the surface of the anodic oxidation layer 1 away from the substrate.

[0093] In some embodiments of the present disclosure, the thickness of the protective layer 3 is 90~110nm.

[0094] In some embodiments of the present disclosure, the first film layer is silicon dioxide, and the second film layer is niobium pentoxide.

[0095] In some embodiments of the present disclosure, taking an alternating layer composed of one layer of the first film layer and one layer of the second film layer as a period, the number of stacking periods of the laminated film 2 is 4.

[0096] In some embodiments of the present disclosure, the housing of the electronic device may be entirely a metal part or partially a metal part, and those skilled in the art can set the housing of the electronic device according to actual needs. In addition, the housing of the electronic device may be entirely treated by a surface treatment method and have a surface with high color saturation, or may be partially treated by a surface treatment method and have a surface with high color saturation. Those skilled in the art can perform surface treatment on the housing of the electronic device according to actual needs to make the corresponding surface have a surface with high saturation color. Exemplarily, for a housing with a surface having a high saturation color after surface treatment, it may have a high saturation color surface as a whole or locally, such as the side wall of the housing, the position of the trademark, etc. For a housing with a locally high saturation color surface, the locally high saturation color surface area and other areas may have the same paint film or different paint films.

[0097] Hereinafter, examples and comparative examples are given to illustrate the embodiments of the present application more specifically. It should be noted that the specific examples below are only for illustration and do not limit the present disclosure.

[0098] Example 1

[0099] This example provides a surface treatment method, including the following steps:

[0100] (1) Use zircon sand (ZrSiO4) with an abrasive grain size of 170#, the corresponding screen aperture is about 90 μm, the pressure is 2.1 kg / cm², and the linear speed is 22 Hz to perform sandblasting on the aluminum alloy part, and the surface roughness of the obtained aluminum alloy part is 0.8 μm.

[0101] (2) At room temperature, immerse the aluminum alloy part in sulfuric acid with a molar concentration of 18 - 22% for anodic oxidation, where the current density is 1 - 2 A / dm², the voltage is a DC voltage of 12 - 18 V, and the oxidation time is 30 min to obtain an anodic oxidation film with a thickness of 12 - 16 μm, and use a black dye to dye the anodic oxidation film.

[0102] (3) Use magnetron sputtering to alternately deposit a silicon dioxide film and a niobium pentoxide film. The coating parameters are a radio frequency power of 200 W, a working gas pressure of 0.5 Pa, the working gas used is argon, the reaction gas is oxygen, the temperature of the anodic oxidation film is 150 °C, and the distance between the silicon target or niobium target is about 60 mm to prepare a laminated film. After repeating the preparation for 4 cycles, a 470 nm thick laminated film is obtained, and stop magnetron sputtering.

[0103] (4) Heat-treat the anodized layer after coating. Use a nickel acetate solution with a mass percentage of 12 - 16% for heat treatment at 93 - 100 °C. After 30 minutes of heat treatment, seal the pore structure of the anodized film, and spray a fluoropolymer with a plasma gun to form an anti-fingerprint coating with a thickness of 100 nm, obtaining the surface-treated aluminum alloy part.

[0104] Test the surface-treated aluminum alloy part of Example 1, and the obtained color difference values are approximately L = 3.6, a = 0.3, b = -4.0, and the glossiness is approximately 1.4°. Figure 4 The physical diagram of the surface-treated aluminum alloy part in Example 1 of the present disclosure is shown. As Figure 4 shown, it can be seen that the aluminum alloy part prepared in Example 1 has a deep and pure black color, and the hand feeling is relatively soft and smooth, achieving a visual effect of making it appear thinner.

[0105] Comparative Example 1:

[0106] The surface treatment process of this Comparative Example 1 is generally the same as that of Example 1. The difference is that in step (1), this Comparative Example 1 uses zircon sand (ZrSiO4) with an abrasive grain size of 170#, the corresponding screen aperture is about 90 μm, the pressure is 2.4 kg / cm², and the linear speed is 24 Hz to sandblast the aluminum alloy part, and the surface roughness of the obtained aluminum alloy part is 1.1 - 1.2 μm.

[0107] Test the surface-treated aluminum alloy part of this Comparative Example 1, and the obtained color difference values are approximately L = 14, a = 0.6, b = 1.95.

[0108] Figure 5 The physical diagram of the surface-treated aluminum alloy part in Comparative Example 1 of the present disclosure is shown. As Figure 5 shown, the aluminum alloy part of this Comparative Example 1 shows a whitening effect compared to Example 1, and its black presentation effect is poor.

[0109] Comparative Example 2:

[0110] The surface treatment process of this Comparative Example 2 is generally the same as that of Example 1. The difference is that in step (3), niobium pentoxide is replaced with titanium oxide (the radio frequency power used remains the same), and the number of coating cycles is also 4 groups.

[0111] Test the surface-treated aluminum alloy part of this Comparative Example 2, and the obtained color difference values are approximately L = 11.70, a = 0.58, b = 0.54.

[0112] Comparing the aluminum alloy part of this Comparative Example 2 with Example 1, it can be seen that although titanium oxide and niobium pentoxide both have a relatively high refractive index, it is difficult to achieve the same effect of restoring the base color as niobium pentoxide.

[0113] Example 2:

[0114] The surface treatment process of this Example 2 is generally the same as that of Example 1. The difference is that before step (3), an alumina base film with a thickness of 30 nm was prepared by magnetron sputtering.

[0115] The aluminum alloy parts after surface treatment in this Example 2 were tested, and the color difference value L was about 3.5, indicating that adding the alumina base film on the basis of Example 1 had little effect on the color difference value. At the same time, the bonding strength between the laminated film system and the anodic oxidation layer was improved, making the surface color of the aluminum alloy parts more uniform and stable.

[0116] Comparative Example 3:

[0117] The surface treatment process of this Comparative Example 3 is generally the same as that of Example 1. The difference is that in this Comparative Example 3, the preparation of the laminated film was not carried out, and only the processes of sandblasting, anodic oxidation, dyeing, and sealing hole heat treatment were carried out.

[0118] The aluminum alloy parts after surface treatment in this Comparative Example 3 were tested, and the color difference value L was about 26, and the glossiness was about 6°.

[0119] Figure 6 Practical diagrams of the aluminum alloy parts after surface treatment in Example 1 and Comparative Example 3 of the present disclosure are shown; among them, a is the practical diagram of Example 1; b is the practical diagram of Comparative Example 3. As Figure 6 shown by the comparison between a and b in, it shows that without preparing the laminated film, the reflectivity of light in Comparative Example 3 is relatively high, and thus the phenomenon of turning white appears, and it is difficult to obtain a high-saturation black.

[0120] Comparative Example 4:

[0121] This Comparative Example 4 used conventional grinding and micro-arc oxidation processes for surface treatment. Grinding can be understood as grinding the surface of the aluminum alloy flat. The micro-arc oxidation process includes the following steps:

[0122] (1) Immerse the aluminum alloy parts in a sodium hydroxide alkaline degreaser at a temperature of 60 °C for 5 - 10 min to remove the oil and impurities on the surface, and then wash them several times with water to wash away the ions in the alkaline degreaser.

[0123] (2) Immerse the aluminum alloy parts in the micro-arc oxidation electrolyte, which includes sodium silicate, sodium hydroxide, sodium chlorate, phosphate, glycerol, etc. At room temperature, oxidize for 30 min at a current density of 10 - 30 A / dm 2 ².

[0124] The surface-treated aluminum alloy parts of this Comparative Example 4 were tested, and the color difference value L was about 18, and the glossiness was about 1.6°. It shows that the method of the present disclosure has a better color rendering effect compared with conventional processes such as micro-arc oxidation. In addition, the glossiness of the aluminum alloy parts after micro-arc oxidation treatment is darker and the wear resistance is poorer.

[0125] Those skilled in the art can understand that the features recited in the various embodiments and / or claims of the present disclosure can be combined or / and combined in various ways, even if such combinations or combinations are not explicitly recited in the present disclosure. In particular, without departing from the spirit and teachings of the present disclosure, the features recited in the various embodiments and / or claims of the present disclosure can be combined and / or combined in various ways. All such combinations and / or combinations fall within the scope of the present disclosure.

[0126] Although the present disclosure has been shown and described with reference to specific exemplary embodiments thereof, those skilled in the art should understand that various changes in form and detail can be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents. Therefore, the scope of the present disclosure should not be limited to the above embodiments, but should be determined not only by the appended claims but also by the equivalents of the appended claims.

Claims

1. A metal part, comprising: Base material; An anodized layer, located on the surface of the substrate, the anodized layer has a base color, and the interior of the anodized layer has a porous structure; A laminated film is located in the pores of the anodized layer; The laminated film comprises a first film layer and a second film layer which are alternately arranged, wherein the refractive index of the first film layer is lower than that of the second film layer, and the laminated film is suitable for reducing the reflection of the anodized layer so that the color presented by the metal part meets a preset condition close to the basic color.

2. The metal part according to claim 1, wherein the total thickness of the laminated film is lower than the roughness of the substrate surface; The metal part is an aluminum alloy part.

3. The metal part according to claim 2, wherein the basic color is black; and the color difference value of the metal part is ≤4.

4. The metal part according to claim 2, wherein the surface roughness of the substrate is 0.7-0.9 μm; The total thickness of the laminated film is 460-480 nm; The thickness of the anodized layer is 12-16 μm.

5. The metal member according to claim 1, further comprising: A base film is located in the holes of the anodized layer and below the laminated film.

6. The metal piece according to any one of claims 1 to 5, further comprising: The protective layer is located on the surface of the anodized layer away from the substrate, and the thickness of the protective layer is 90-110 nm.

7. The metal part according to any one of claims 1 to 5, wherein the first film layer is silicon dioxide, and the second film layer is niobium pentoxide; One period is composed of an alternating layer consisting of a first film layer and a second film layer, and the number of the stacking periods of the stacked film is 4.

8. A surface treatment method for a metal part, comprising: The substrate of the metal part is subjected to anodizing and coloring treatment in sequence to obtain a metal part having an anodized layer on the surface, wherein the anodized layer has a basic color and a porous structure; Performing a first coating treatment on the surface of the metal part by magnetron sputtering, alternately depositing a first film layer and a second film layer in the holes of the anodized layer, to obtain a metal part having a laminated film on the surface; Heat-treating the surface of the metal part having the laminated film on the surface, wherein the heat-treating is performed under the action of a sealing agent to seal the porous structure of the anodized layer to obtain a surface-treated metal part; The refractive index of the first film layer is lower than that of the second film layer, and the laminated film is suitable for reducing the reflection of the anodized layer so that the color presented by the metal part meets a preset condition close to the basic color.

9. The surface treatment method according to claim 8, before performing the first coating treatment, further comprising: Performing a second coating treatment on the surface of the anodized layer of the metal part by magnetron sputtering to deposit a base film in the holes of the anodized layer of the metal part; The material of the base film is metal oxide, and the thickness of the base film is 20-40 nm.

10. An electronic device, comprising a housing, at least part of which is formed by a metal member, the metal member comprising: Base material; An anodized layer, located on the surface of the substrate, the anodized layer has a base color, and the interior of the anodized layer has a porous structure; A laminated film is located in the pores of the anodized layer; The laminated film comprises a first film layer and a second film layer which are alternately arranged, wherein the refractive index of the first film layer is lower than that of the second film layer, and the laminated film is suitable for reducing the reflection of the anodized layer so that the color presented by the metal part meets a preset condition close to the basic color.

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