CN115341254A

CN115341254A - Surface treatment method

Info

Publication number: CN115341254A
Application number: CN202110529101.8A
Authority: CN
Inventors: 刘兵
Original assignee: Beijing Xiaomi Mobile Software Co Ltd
Current assignee: Beijing Xiaomi Mobile Software Co Ltd
Priority date: 2021-05-14
Filing date: 2021-05-14
Publication date: 2022-11-15

Abstract

The present disclosure relates to a surface treatment method. The surface treatment method comprises the following steps: obtaining a metal base material; treating the metal substrate to form a porous layer on at least one side of the metal substrate, the porous layer comprising a plurality of micropores; performing a dyeing process on the metal base material to form a colored layer in the plurality of micropores; and carrying out hole sealing treatment in at least two stages aiming at the micropores on the metal substrate so as to form a hole sealing layer and a non-sensitized contact layer which are filled in the micropores, wherein the hole sealing layer covers the coloring layer, and the non-sensitized contact layer covers the hole sealing layer. Through in this disclosure in the micropore form cover the hole sealing layer of dyed layer protect the dyed layer, avoid the decoloration or at the bleeding of hole sealing process in-process, and through forming the non-sensitization contact layer that covers the hole sealing layer, can prevent on the one hand that the material in hole sealing layer from appearing, on the other hand can avoid the user to grip metal product allergy, promotes user experience.

Description

Surface treatment method

Technical Field

The disclosure relates to the technical field of surface treatment, in particular to a surface treatment method.

Background

In order to meet the aesthetic requirements of users on terminal equipment and improve the market competitiveness of the terminal equipment, various manufacturers perform surface treatment on the metal shell of the terminal equipment, and the surface of the treated metal shell can present different colors. In a related art, the processed metal casing may generally include a nickel material layer on the outermost layer, which a user usually contacts directly when holding the terminal device, and nickel is a sensitizing element of a human body, which is easy to cause allergy to the user and is not user-friendly.

Disclosure of Invention

The present disclosure provides a surface treatment method to solve the disadvantages of the related art.

According to a first aspect of embodiments of the present disclosure, there is provided a surface treatment method including:

obtaining a metal base material;

treating the metal substrate to form a porous layer on at least one side of the metal substrate, the porous layer comprising a plurality of micropores;

performing a dyeing process on the metal base material to form a colored layer within the plurality of micropores;

and carrying out hole sealing treatment in at least two stages aiming at the micropores on the metal substrate so as to form a hole sealing layer and a non-sensitized contact layer which are filled in the micropores, wherein the hole sealing layer covers the coloring layer, and the non-sensitized contact layer covers the hole sealing layer.

Optionally, the bonding strength between the hole sealing layer and the inner wall of the micro-hole is greater than that between the non-sensitized contact layer and the inner wall of the micro-hole.

Optionally, the sealing treatment is performed on the micropores on the metal substrate in at least two stages to form a sealing layer and a non-sensitized contact layer filled in the micropores, and the method further includes:

placing the metal substrate in a first closed tank filled with first tank liquor to perform first-stage hole sealing treatment so as to form a hole sealing layer covering the coloring layer;

and placing the metal substrate in a second closed tank filled with second tank liquor to execute second-stage hole sealing treatment so as to deposit a non-sensitized contact layer covering the hole sealing layer in the micropores.

Optionally, the first bath solution comprises a nickel salt solution.

Optionally, the PH of the first bath solution is greater than or equal to 5.5 and less than or equal to 6.

Optionally, the concentration of the nickel salt in the nickel salt solution is greater than or equal to 8 grams per liter and less than or equal to 15 grams per liter.

Optionally, the placing the metal substrate in a first closed tank filled with a first tank solution to perform a first stage sealing treatment to form a sealing layer covering the colored layer includes:

and placing the metal substrate in a first tank liquor to be soaked for a first time length to form the hole sealing layer, wherein the first time length is greater than or equal to 10 minutes.

Optionally, the first time period is greater than or equal to 15 minutes and less than or equal to 20 minutes.

Optionally, the temperature of the first bath solution is greater than or equal to 93 ℃ and less than or equal to 98 ℃.

Optionally, the second bath solution comprises a cerium salt solution and/or a lithium salt solution.

Optionally, the second bath solution further comprises ammonium persulfate and/or potassium permanganate.

Optionally, the concentration of the ammonium persulfate is less than or equal to 2.5 grams per liter;

the concentration of the potassium permanganate is more than or equal to 0.2 gram per liter and less than or equal to 5 grams per liter.

Optionally, the second bath solution comprises a solution of cerium sulfate tetrahydrate.

Optionally, the concentration of the cerium sulfate tetrahydrate is greater than or equal to 5 grams per liter, less than or equal to 50 grams per liter.

Optionally, the temperature of the second bath solution is greater than or equal to 80 ℃ and less than or equal to 98 ℃.

Optionally, the step of placing the metal substrate in a second closed tank filled with a second tank solution to perform a second-stage hole sealing treatment so as to deposit a non-sensitized contact layer covering the hole sealing layer in the micropores includes:

and placing the metal substrate in a second closed tank filled with a second tank solution to be soaked for a second time to form the non-sensitized contact layer, wherein the second time is more than or equal to 8 minutes.

Optionally, the second time period is greater than or equal to 8 minutes and less than or equal to 10 minutes.

Optionally, the thickness of the hole sealing layer is greater than or equal to 6 microns.

Optionally, the thickness of the non-sensitizing contact layer is greater than or equal to 3 microns.

Optionally, the treating the metal substrate to form a porous layer on at least one side of the metal substrate comprises:

and carrying out anodic oxidation treatment on the metal substrate by using an acid electrolyte to form a porous layer and a barrier layer on the surface of the metal substrate, wherein the barrier layer is positioned between the porous layer and the metal substrate.

Optionally, the electrolyte at least comprises one or more of the following components: oxalic acid, sulfuric acid, phosphoric acid, and chromic acid.

Optionally, the diameter of the micropores is greater than or equal to 10 nanometers.

Optionally, the metal substrate comprises an aluminum alloy substrate, an aluminum substrate, a magnesium alloy substrate, or a titanium alloy substrate.

The technical scheme provided by the embodiment of the disclosure can have the following beneficial effects:

known by the above-mentioned embodiment, through the surface treatment technology that provides in this disclosure, can form the hole sealing layer that covers the dyed layer in the micropore of porous layer, utilize the combination of hole sealing layer and micropore inner wall to protect the coloring layer, avoid the decoloration or at hole sealing process in-process flowing color, and through the non-sensitization contact layer that forms the cover hole sealing layer, can prevent that the material in hole sealing layer from appearing on the one hand, and on the other hand can avoid the user to hold metal product allergy, promotes user experience.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and together with the description, serve to explain the principles of the disclosure.

FIG. 1 is a flow chart illustrating a method of surface treatment according to an exemplary embodiment.

FIG. 2 is a flow chart illustrating another method of surface treatment according to an exemplary embodiment.

FIG. 3 is a schematic cross-sectional view of a metal article shown according to an exemplary embodiment.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used in this disclosure and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

It is to be understood that although the terms first, second, third, etc. may be used herein to describe various information, such information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present disclosure. The word "if," as used herein, may be interpreted as "at … …" or "at … …" or "in response to a determination," depending on the context.

The present disclosure provides a surface treatment method as described in fig. 1, which can be applied to a metal product, for example: the metal product can be applied to terminal equipment, such as: the metal product can be a metal frame, a shell, a buckle or a magnetic suction interface and the like. Specifically, the surface treatment method may include the steps of:

in step 101, a metal substrate is obtained.

In this embodiment, the metal substrate may include an aluminum substrate or an aluminum alloy substrate, which is advantageous for achieving weight reduction of the metal product for the terminal equipment configuring the metal product. The metal substrate may be obtained by machining a raw material, for example, the metal substrate may be obtained by one or more of CNC machining, polishing, sand blasting, and wire drawing, and the machined metal substrate may be subsequently cleaned with pure water and then dried for subsequent treatment. The metal substrate is only exemplified to include an aluminum substrate or an aluminum alloy substrate, and in other embodiments, the metal substrate may further include a magnesium alloy substrate or a titanium alloy substrate or other metal substrates, which is not limited by the disclosure.

In step 102, a metal substrate is treated to form a porous layer on at least one side of the metal substrate, the porous layer comprising a plurality of micropores.

In one embodiment, the metal substrate may be anodized using an acidic electrolyte solution to form a barrier layer and a porous layer on the surface of the metal substrate, the barrier layer being located between the porous layer and the metal substrate, and the density of the barrier layer being greater than the density of the porous layer to block a colored layer subsequently deposited within the pores of the porous layer. The electrolyte of the anodic oxidation treatment may be an acid electrolyte, for example, the acid electrolyte may include one or more acids of oxalic acid, sulfuric acid, chromic acid, and phosphoric acid. For example, the acid electrolyte may include a sulfuric acid solution, wherein a concentration of sulfuric acid in the sulfuric acid solution may be greater than or equal to 150g/L (grams per liter) and less than or equal to 220g/L (grams per liter), a concentration of aluminum protons may be greater than or equal to 5mg/L (milligrams per liter) and less than or equal to 15mg/L (milligrams per liter), an oxidation voltage may be 12.5V (volts), a temperature of the anodizing electrolyte may be greater than or equal to 10 ℃ and less than or equal to 14 ℃, and an oxidation time period may be 30-60 minutes. By treating the surface of the metal substrate with the acid electrolyte, an oxidation layer including a barrier layer and a porous layer can be formed, and the wear resistance and hardness of a subsequent metal product can be improved by the oxidation layer. Of course, the example of forming the porous layer by performing the anodic oxidation treatment on the metal substrate is only given here, and in other embodiments, the porous layer may be formed by other processes, for example, the porous layer may be formed by performing an etching process or an etching process on the metal substrate, and the porous layer may be directly formed on the surface of the metal substrate, which is not limited in the present disclosure.

In step 103, a dyeing process is performed on the metal base material to form a colored layer within the plurality of micropores.

In this embodiment, in order to realize color display of a metal product, a coloring layer may be formed by performing a dyeing process on the metal base material on which the porous layer is formed, and the coloring layer may be deposited in each of the micropores. In one embodiment, the metal simple substance or the metal oxide particles can be deposited at the bottom of the micropores through an electrolytic coloring process, the metal product can present different colors due to the light scattering effect, and the number of the deposited particles can be adjusted by adjusting the coloring time and the applied voltage of the electrolytic coloring process, so that the purpose of adjusting the color depth is achieved. In another embodiment, the coloring may be performed by a dyeing process, and specifically, the metal substrate on which the porous layer is formed may be placed in a solution containing a dye, and the micropores of the porous layer form a colored layer by adsorbing the dye.

In step 104, at least two stages of sealing treatment are performed on the micropores on the metal substrate to form a sealing layer and a non-sensitizing contact layer filled in the micropores, wherein the sealing layer covers the colored layer, and the non-sensitizing contact layer covers the sealing layer.

In this embodiment, carry out the hole sealing of a plurality of stages to the micropore on the metal substrate and handle, can form the different hole sealing layer of material and non-sensitized contact layer in the micropore, utilize the combination of hole sealing layer and micropore inner wall to protect the chromatograph, avoid the decoloration or at hole sealing process in-process flowing color, and through the non-sensitized contact layer that forms the cover hole sealing layer in the micropore, can prevent hole sealing layer's hole sealing material on the one hand and precipitate, on the other hand can avoid the user to hold metal product allergy, promotion user experience. The bonding strength of the hole sealing layer and the inner wall of the micropore is larger than that of the non-sensitized contact layer and the inner wall of the micropore, so that compared with the scheme of adopting a nickel-free hole sealing process in the related technology, the protection of a color layer can be enhanced, and particularly, the bleeding can be reduced in the hole sealing process.

For the sealing treatment process of at least two stages in the above embodiment, the following will take two-stage sealing treatment for micropores as an example.

The metal substrate with the dyeing layer formed thereon can be placed in a first closed tank filled with a first tank solution to perform a first-stage hole sealing treatment, so as to deposit a hole sealing layer covering the dyeing layer in the micropores. And then placing the metal substrate with the hole sealing layer in a second closed tank filled with second tank liquor to perform second-stage hole sealing treatment so as to deposit a non-sensitized contact layer covering the hole sealing layer in the micropores, thereby obtaining the metal product.

Wherein, first tank liquor can include nickel salt solution, use nickel salt solution as the nickel acetate solution for example, place the metal substrate who forms the dyed layer after will colouring in the first closed tank that is equipped with nickel acetate solution, carry out first stage hole sealing and handle, through this first stage hole sealing handle can be in the compound layer of the nickel of micropore deposit cover dyed layer, utilize the stronger characteristics of the compound layer of nickel and the bonding nature of micropore inner wall, can avoid the compound layer of nickel to drop, realize the protection to the chromatograph, can promote the corrosion resistance of metal product after the shaping simultaneously. The nickel salt solution is only exemplified to include nickel acetate, and in other embodiments, the nickel salt solution may further include nickel acetate or nickel chromate, etc., which are not limited by the present disclosure.

In the first-stage hole sealing treatment process, the pH value of the first tank liquor can be greater than or equal to 5.5 and less than or equal to 6, and frost or pitting can be avoided after hole sealing in the pH value range, so that the hole sealing quality can be ensured, and the hole sealing agent has good corrosion resistance and wear resistance. The concentration of nickel salt in the nickel salt solution may be greater than or equal to 8g/L (gram per liter) and less than or equal to 15g/L (gram per liter), for example, when the nickel salt solution includes a nickel acetate solution, the concentration of nickel salt, that is, the concentration of nickel acetate in the nickel salt solution is greater than or equal to 8g/L (gram per liter) and less than or equal to 15g/L (gram per liter), so as to ensure the concentration of nickel ions in the nickel salt solution and ensure the sealing quality. Further, the temperature of the first bath solution may be greater than or equal to 93 ℃ and less than or equal to 98 ℃, at which the corrosion resistance of the nickel compound layer formed is strong. The first-stage hole sealing process can be to place the metal substrate in a first tank liquor to be soaked for a first time length, wherein the first time length can be more than or equal to ten minutes, preferably the first time length can be less than or equal to thirty minutes, the thickness of the formed hole sealing layer can be adjusted by controlling the first time length, and the thickness of the hole sealing layer in the micropores can be effectively controlled within the time length range, so that certain space can be reserved in the micropores for the subsequent deposition of the non-sensitized contact layer. Preferably, the first time period may be greater than or equal to fifteen minutes and less than or equal to twenty minutes, so as to form a hole sealing layer with a thickness greater than or equal to 6 micrometers in the micropores, and preferably, the thickness of the hole sealing layer may also be less than or equal to 8 micrometers, so that the hole sealing layer can give room for depositing a non-sensitized contact layer while having certain corrosion resistance and bonding strength in the time period.

The second bath can include at least one of a cerium salt solution and a lithium salt solution, for example, the second bath can include a cerium sulfate tetrahydrate solution, and the metal substrate with the sealed layer formed thereon can be placed in the cerium sulfate tetrahydrate solution for soaking for a second period of time to form a non-sensitized contact layer. The second period of time may be greater than or equal to eight minutes, and preferably, the second period of time may be less than or equal to thirty minutes. The concentration of the tetrahydrate cerium sulfate in the tetrahydrate cerium sulfate solution is less than or equal to 2.5g/L, a non-sensitized contact layer covering a seal hole layer can be deposited in the micropores, the non-sensitized contact layer forms the appearance surface of a metal product, and when the metal product is configured to a terminal device, the non-sensitized contact layer can form a part of the outer surface of the terminal device, so that user allergy can be avoided, and user experience is improved. Of course, in the embodiments of the present disclosure, only the second bath solution includes at least one of the cerium salt solution and the lithium salt solution to form the non-sensitizing contact layer is taken as an example for explanation, and in other embodiments, the second bath solution may further include compound solutions of salts of other non-sensitizing materials, which is not limited by the present disclosure.

Wherein, the temperature of the second bath solution can be more than or equal to 80 ℃ and less than or equal to 98 ℃ so as to form a non-sensitized contact layer with better corrosion resistance at the temperature. Preferably, the soaking time of the metal substrate in the second bath solution can be greater than or equal to eight minutes and less than or equal to ten minutes, and the thickness of the deposited non-sensitized contact layer can be adjusted by adjusting the soaking time to keep the thickness within a reasonable thickness range. For example, the thickness of the non-sensitized contact layer can be greater than or equal to 3 micrometers, the preferable thickness of the non-sensitized contact layer can be less than or equal to 4 micrometers, the situation that the bonding strength between the non-sensitized contact layer and the inner wall of the micropore is too weak due to too thin non-sensitized contact layer to cause falling off is avoided, and the situation that the non-sensitized contact layer protrudes out of the micropore due to too thick non-sensitized contact layer to influence the appearance and the touch is also avoided.

In this embodiment, in order to improve the corrosion resistance of the non-sensitized contact layer, the second bath solution may include a cerium salt, ammonium persulfate and potassium permanganate, and the conversion of trivalent cerium ions to tetravalent cerium ions may be promoted by the ammonium persulfate and the potassium permanganate, so as to precipitate a cerium compound layer with better corrosion resistance in the micropores 31, and the cerium compound layer may include a bonding layer of cerium hydroxide and cerium dioxide, so as to improve the corrosion resistance of the non-sensitized contact layer 6. Wherein the concentration of ammonium persulfate in the second bath solution is less than or equal to 2.5g/L; the concentration of the potassium permanganate can be more than or equal to 0.2g/L and less than or equal to 5g/L, the thickness of the deposited cerium compound layer can be adjusted by controlling the concentrations of the ammonium persulfate and the potassium permanganate to be controlled within a reasonable range, and the cerium compound layer is the non-sensitized contact layer 6. In other embodiments, the nonsensitizing contact layer 6 may also include a cerium hydroxide layer or a cerium oxide layer. The second bath solution is only exemplified to include a cerium salt, ammonium persulfate and potassium permanganate, and in other embodiments, the second bath solution may also include a cerium salt and ammonium persulfate, or a cerium salt and potassium permanganate, which is not limited by the present disclosure. In still other embodiments, the solution may be a mixed solution of a compound of a metal salt of other non-sensitizing material and at least one of ammonium persulfate and potassium permanganate. In other embodiments, the nonsensitizing contact layer 6 may include a lithium compound layer or a bonding layer of a cerium compound and a lithium compound by adjusting the second bath solution, which is not limited by the present disclosure.

The second bath solution is only exemplified to include a cerium salt solution, an ammonium persulfate solution and a potassium permanganate solution, and in other embodiments, the second bath solution may also include a cerium salt solution and an ammonium persulfate solution, or a cerium salt solution and a potassium permanganate solution, which is not limited by the present disclosure. In still other embodiments, the solution may be a mixed solution of a compound solution of a salt of another non-sensitizing material and at least one of an ammonium persulfate solution and a potassium permanganate solution.

Known by the implementation, through the surface treatment technology that provides in this disclosure, can form the hole sealing layer that covers the dyed layer in the micropore of porous layer, utilize the combination of hole sealing layer and micropore inner wall to protect the painted layer, avoid the decoloration or at hole sealing process in-process flowing color, and through the non-sensitization contact layer who forms the cover hole sealing layer, can prevent on the one hand that the material in hole sealing layer from appearing, on the other hand can avoid the user to hold metal product allergy, promotes user experience.

To elaborate on the technical solution of the present disclosure, as shown in fig. 2, the surface treatment method may include:

in step 201, a metal substrate is obtained.

In step 202, the metal substrate is dried after the pure water cleaning.

In this embodiment, the metal base material is cleaned by pure water, so that the surface of the metal base material can be cleaned, which is beneficial to oxidizing the metal base material in the subsequent process. After cleaning, the metal substrate can be dried, so that the influence of residual water stain on the subsequent process is avoided.

In step 203, the metal substrate is oxidized in an acidic electrolyte to form a barrier layer and a porous layer, the barrier layer being located between the metal substrate and the porous layer.

In this example, a continuous, non-porous barrier layer may be formed on the surface due to the rapid rise in voltage at the beginning of oxidation of the metal substrate by the acid electrolyte; subsequently, as the electrochemical reaction proceeds and the voltage is slowly changed, a porous layer may be formed on the barrier layer, and the porous layer may include micropores having a diameter greater than or equal to 10 nm, preferably, a diameter less than or equal to 80 nm, which is favorable for the subsequent deposition of the dye.

In step 204, pure water cleans the metal substrate on which the porous layer is formed.

In this embodiment, the metal base material on which the oxide film layer is formed may be cleaned by pure water, so as to prevent the acid electrolyte from remaining on the surface of the metal base material and prevent the subsequent dyeing process from being affected.

In step 205, the metal substrate is dyed using a dyeing process to form a colored layer.

In this embodiment, the metal substrate may be placed in a staining solution, the dye may be deposited in the micropores of the porous layer, and different dyes may be configured to allow the metal substrate to exhibit different colors, thereby satisfying the diversified demands of the user population for colors.

In step 206, a hole sealing treatment is performed by a first hole sealing stage treatment process to form a hole sealing layer covering the colored layer on the case to be sealed.

In this embodiment, the sealing layer formed by the first sealing-stage sealing process may be filled in the micropores, and the sealing layer covers the colored layer. The hole sealing layer can comprise a nickel layer or a nickel-based compound, so that the coloring layer can be protected through good bonding property between nickel and the oxide film, and meanwhile, the corrosion resistance of the surface of the metal product is improved. The thickness of the pore sealing layer is greater than or equal to 6 microns, and preferably can be less than or equal to 8 microns.

In step 207, a hole sealing treatment is performed by a second hole sealing stage treatment process to form a non-sensitized contact layer covering the nickel compound layer, and a metal product is obtained.

In this embodiment, a non-sensitized contact layer covering the hole sealing layer can be formed by performing the hole sealing treatment by the second hole sealing stage treatment process, and different non-sensitized contact layers can be formed by using different second bath solutions in the second hole sealing stage treatment process. For example, the second bath may comprise a cerium salt solution and the non-sensitizing contact layer may comprise a layer of a cerium compound, or the second bath may comprise a lithium salt solution and the non-sensitizing contact layer may comprise a layer of a lithium compound, or the second bath may comprise a cerium salt solution and a lithium salt solution and the non-sensitizing contact layer may comprise a bonding layer of a cerium compound and a lithium compound. Of course, the above description only takes the case that the second bath solution includes the cerium salt solution and the lithium salt solution as an example, in other embodiments, the second bath solution may also include other solutions of non-sensitizing materials, and the disclosure does not limit this.

In step 208, the metal article is cleaned and dried.

In this embodiment, the metal product after hole sealing can be cleaned with pure water, and then dried. The metal product can be a shell, a frame, a magnetic suction interface or a buckle and the like.

Based on the above-described embodiment, as shown in fig. 3, the present disclosure also provides a metal article 100, and the metal article 100 may include a metal substrate 1, a barrier layer 2, a porous layer 3, a colored layer 4, a hole-sealing layer 5, and a non-sensitizing contact layer 6. The barrier layer 2 is formed on the surface of the metal substrate 1, the porous layer 3 is formed on the surface of the barrier layer 2, the coloring layer 4 is formed on the surface of the porous layer 3, and the coloring layer 4 is filled in the micropores 31 included in the porous layer 3, so that the coloring layer 4 is used for decorating the color display of the metal product 100, and the aesthetic property of the metal product 100 is improved.

And wherein, since the colored layer 4 is disposed in the micropores 31 of the porous layer 3, in order to avoid discoloration, a sealing process may be performed with respect to the metal base material 1 on which the colored layer 4 is formed, specifically, the metal base material 1 may be placed in a first closed tank containing a first tank liquid to perform a first-stage sealing treatment to deposit the sealing layer 5 covering the colored layer 4 in the micropores 31, and then the metal base material 1 may be placed in a second closed tank containing a second tank liquid to perform a second-stage sealing treatment to deposit the unsensitized contact layer 6 covering the sealing layer 5 in the micropores 31. Based on this, can form the hole sealing layer 5 that covers the chromatograph 4 in the micropore, utilize the combination of hole sealing layer 5 and micropore inner wall to protect to the chromatograph 4, avoid the decoloration or flow in the hole sealing process, and through form the non-sensitization contact layer 6 that covers hole sealing layer 5 in micropore 31, can prevent on the one hand that the hole sealing material of hole sealing layer 5 from appearing, on the other hand can avoid the user to hold metal product 100 allergy, promotes user experience. For other structural parameters of the metal product 100 in this embodiment, reference may be made to the above process embodiments, and details are not repeated here.

Based on the metal product 100, the present disclosure also provides a terminal device (not shown), the terminal device may include the metal product 100, the metal product 100 may serve as an external casing or a frame of the terminal device, and the non-sensitized contact layer 6 of the metal product 100 may form a part of an external surface of the terminal device, so as to prevent user allergy and improve user experience. The terminal device may include a mobile phone terminal or other wearable devices, such as a watch, a bracelet, a cervical massager, and the like.

Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice in the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

It will be understood that the present disclosure is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A surface treatment method, characterized by comprising:

obtaining a metal base material;

and carrying out at least two stages of hole sealing treatment on the micropores on the metal substrate to form a hole sealing layer and a non-sensitized contact layer which are filled in the micropores, wherein the hole sealing layer covers the coloring layer, and the non-sensitized contact layer covers the hole sealing layer.

2. The surface treatment method according to claim 1, wherein the bonding strength of the pore-sealing layer to the inner walls of the micropores is greater than the bonding strength of the non-sensitizing contact layer to the inner walls of the micropores.

3. The surface treatment method according to claim 1, wherein the sealing treatment is performed for the micropores on the metal substrate in at least two stages to form a sealing layer and a non-sensitizing contact layer filled in the micropores, further comprising:

placing the metal substrate in a first closed groove filled with first groove liquid to perform first-stage hole sealing treatment so as to form a hole sealing layer covering the coloring layer;

4. A surface treatment method according to claim 3, characterized in that said first bath comprises a nickel salt solution.

5. The surface treatment method according to claim 3 or 4, wherein the pH of the first bath is 5.5 or more and 6 or less.

6. The surface treatment method according to claim 4, wherein the concentration of the nickel salt in the nickel salt solution is 8g or more per liter and 15g or less per liter.

7. The surface treatment method according to claim 3, wherein the placing the metal substrate in a first closed tank containing a first bath solution to perform a first-stage sealing treatment to form a sealing layer covering the colored layer comprises:

8. The surface treatment method according to claim 7, wherein the first period is greater than or equal to 15 minutes and less than or equal to 20 minutes.

9. The surface treatment method according to claim 3, wherein the temperature of the first bath solution is greater than or equal to 93 degrees Celsius and less than or equal to 98 degrees Celsius.

10. A surface treatment process according to claim 3, characterized in that said second bath comprises a solution of cerium salt and/or a solution of lithium salt.

11. The surface treatment method according to claim 10, wherein the second bath solution further comprises ammonium persulfate and/or potassium permanganate.

12. The surface treatment method according to claim 11, wherein the concentration of the ammonium persulfate is less than or equal to 2.5 grams per liter;

13. A surface treatment method according to claim 3, wherein said second bath solution comprises a solution of cerium sulfate tetrahydrate.

14. A surface treatment method according to claim 13, wherein the concentration of said cerium sulfate tetrahydrate is 5g or more per liter, 50g or less per liter.

15. The surface treatment method according to claim 3, wherein the temperature of the second bath solution is 80 degrees Celsius or higher and 98 degrees Celsius or lower.

16. The surface treatment method according to claim 3, wherein the placing of the metal substrate in a second closed bath containing a second bath solution to perform a second-stage sealing treatment for depositing a non-sensitizing contact layer covering the sealing layer in the micropores comprises:

17. The surface treatment method according to claim 16, wherein the second period of time is greater than or equal to 8 minutes and less than or equal to 10 minutes.

18. The surface treatment method according to claim 1, wherein the thickness of the pore-sealing layer is greater than or equal to 6 μm.

19. The surface treatment method according to claim 1, wherein the nonsensitizing contact layer has a thickness of 3 μm or more.

20. The surface treatment method according to claim 1, wherein the treating the metal substrate to form a porous layer on at least one side of the metal substrate comprises:

21. A surface treatment method according to claim 20, wherein the electrolyte comprises at least any one or more of:

oxalic acid, sulfuric acid, phosphoric acid, and chromic acid.

22. A surface treatment method according to claim 1, wherein the diameter of the micropores is 10 nm or more.

23. The surface treatment method according to claim 1, wherein the metal substrate comprises an aluminum alloy substrate, an aluminum substrate, a magnesium alloy substrate, or a titanium alloy substrate.