CN110359045B

CN110359045B - Aluminum alloy member with plating layer and surface treatment method

Info

Publication number: CN110359045B
Application number: CN201810254771.1A
Authority: CN
Inventors: 朱旭; 蔡明�; 李龙雨; 姜文杰
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2018-03-26
Filing date: 2018-03-26
Publication date: 2021-02-12
Anticipated expiration: 2038-03-26
Also published as: CN110359045A; WO2019184781A1

Abstract

The present embodiment provides an aluminum alloy member with a plated layer and a surface treatment method, the aluminum alloy member with a plated layer including an aluminum alloy base material, an alloy plating layer, a first PVD layer, and a second PVD layer, the alloy plating layer and the first PVD layer forming a coherent interface or a semi-coherent interface therebetween; the alloy electroplated layer is arranged between the aluminum alloy base material and the first PVD layer; the first PVD layer is disposed between the aluminum alloy substrate and the second PVD layer. The aluminum alloy component that has the coating that this embodiment provided, it has the alloy plating layer to electroplate on the aluminum alloy base material, there is first PVD layer on the plating layer, there is the second PVD layer on the first PVD layer, first PVD layer is the transition layer, the second PVD layer is the colour layer, interface between alloy plating layer and the transition layer is coherent interface or half coherent interface, this aluminum alloy component rete that has the coating is high, wear-resisting and anti-scratch performance is good, high bright outward appearance effect is pleasing to the eye, simple process, low in production cost.

Description

Aluminum alloy member with plating layer and surface treatment method

Technical Field

The present embodiments relate to the field of surface treatment, and more particularly, to an aluminum alloy member having a plated layer and a surface treatment method.

Background

With the application and popularization of glass and ceramic materials in the field of consumer electronics, the current metal materials for appearance also tend to adopt a high-brightness and transparent-appearance surface effect to form an integral (One Piece) effect with the glass or ceramic materials, so that the precision of the whole machine is improved. Most of the current metal materials for consumer electronics are aluminum alloy and stainless steel. Stainless steel has at least two times higher hardness compared to aluminum alloy, and has long Cycle Time (CT) for Numerical Control (CNC) machining of stainless steel, and large tool wear, which results in high CNC machining price and insufficient productivity of stainless steel. Therefore, the mainstream material of the current metal material for consumer electronics is aluminum alloy.

Currently, the surface treatment scheme for forming a high-brightness appearance on the aluminum alloy is anodic oxidation, and the high-brightness treatment can be performed before anodic oxidation (or after anodic oxidation, or before and after anodic oxidation). The surface treatment scheme has the following problems: (1) the glossiness can not reach the effect of Physical Vapor Deposition (PVD) treatment of stainless steel, can not avoid obvious shading, and is limited by the problems of different colors of the anode, pockmarks, material grains and the like of aluminum alloy, and the highlight effect is only applied to dark color series. (2) The anodic oxide film is thin, low in hardness, poor in toughness and poor in scratch resistance, and the problem of paint falling is easily caused. High defect rates occur with the anodized version to produce a bright appearance.

Disclosure of Invention

The embodiment provides an aluminum alloy member with a coating and a surface treatment method, which can improve the film bonding force, enhance the wear resistance and scratch resistance, have a beautiful high-brightness appearance effect, are simple in process and are low in production cost.

In one aspect, an aluminum alloy component with a plating layer is provided, comprising an aluminum alloy base material, an alloy plating layer, a first Physical Vapor Deposition (PVD) layer and a second PVD layer, wherein a coherent interface or a semi-coherent interface is formed between the alloy plating layer and the first PVD layer; the alloy electroplated layer is arranged between the aluminum alloy base material and the first PVD layer; the first PVD layer is disposed between the aluminum alloy substrate and the second PVD layer.

The aluminum alloy component with the coating that this aspect provided has the alloy plating layer on the aluminum alloy substrate, has first PVD layer on the plating layer, has the second PVD layer on the first PVD layer, and the interface between alloy plating layer and the first PVD layer is coherent interface or half coherent interface, and this aluminum alloy component rete with the coating has the high binding power, and wear-resisting and anti-scratch performance is good, and high bright outward appearance effect is pleasing to the eye, simple process, low in production cost.

In this aspect, the first PVD layer may be considered a PVD transition layer; the second PVD layer may be considered a PVD color layer.

The first PVD layer in this aspect may be a composition gradient transition layer.

In one possible implementation of this aspect, a coherent or semi-coherent interface is formed between the first PVD layer and the second PVD layer. The coherent or semi-coherent interface may ensure a high bonding force between the layers, and therefore in this possible implementation, it is desirable to maintain the coherent or semi-coherent interface between the first PVD layer and the second PVD layer.

In one possible implementation of this aspect, the first PVD layer includes a first metal element that is the same as or has the same lattice type as a largest mass percentage of metal elements in the alloy electroplated layer. The first metal element of the first PVD layer in this possible implementation manner may generally form a coherent interface or a semi-coherent interface between the alloy electroplated layer and the first PVD layer, which may improve the bonding force of the prepared aluminum alloy member film with the plated layer.

In one possible implementation manner of this aspect, the first PVD layer may further include a second metal element, and the second metal element is the same as or has the same lattice type as the base metal element in the second PVD layer. The second metal element of the first PVD layer in this possible implementation manner may generally form a coherent interface or a semi-coherent interface between the first PVD layer and the second PVD layer, which may improve the bonding force of the prepared film layer of the aluminum alloy member with the plating layer.

In a possible implementation manner of this aspect, the first PVD layer sequentially includes a first sub-transition layer, a second sub-transition layer, and a third sub-transition layer from the alloy electroplated layer to the second PVD layer, where the first sub-transition layer includes the first metal element as a component, the second sub-transition layer includes the first metal element and the second metal element as a component, and the third sub-transition layer includes the second metal element as a component. In the possible implementation manner, the three sub-transition layers of the first PVD layer enable the prepared alloy electroplated layer to have good bonding force with the second PVD layer.

In one possible implementation of this aspect, the alloy plating layer has a composition of a binary alloy or a ternary alloy.

In one possible implementation of this aspect, the binary alloy includes a CuSn alloy, a NiP alloy, a CuZn alloy, a FeZn alloy, a ZnNi alloy, a ZnTi alloy, or a SnCe alloy, and the ternary alloy includes a CuSnZn alloy, a SnCoZn alloy, a SnNiZn alloy, or a SnNiCo alloy. The binary alloy or the ternary alloy in the possible implementation mode has high glossiness, has good bonding performance with an aluminum alloy base material, does not need other plating layer priming and surface brightening, and has excellent wear resistance.

In one possible implementation of this aspect, the alloy plating layer has a thickness greater than or equal to 0.5 microns and less than or equal to 50 microns.

In one possible implementation of this aspect, the total thickness of the first PVD layer and the second PVD layer is greater than or equal to 0.5 microns and less than or equal to 7 microns.

In one possible implementation manner of this aspect, the aluminum alloy substrate is a profile aluminum alloy substrate or a die-cast aluminum alloy substrate. In the possible realization mode, the section aluminum alloy base material or the die-casting aluminum alloy base material can be coated.

In one possible implementation of this aspect, the aluminum alloy member with a plating layer is an exterior piece of the terminal device.

In one possible implementation of this aspect, the composition of the second PVD layer is a nitride, carbide, oxide, nitrocarbide, oxycarbide, or oxynitride of the base metal element.

In another aspect, a surface treatment method is provided, including: preparing an alloy electroplated layer on the surface of the aluminum alloy base material by an electroplating method; preparing a first PVD layer on the alloy electroplated layer by a Physical Vapor Deposition (PVD) method; and preparing a second PVD layer on the first PVD layer by a PVD method to obtain the aluminum alloy component with a plated layer, wherein a coherent interface or a semi-coherent interface is formed between the alloy electroplated layer and the first PVD layer.

According to the surface treatment method, the alloy electroplated layer is electroplated on the aluminum alloy base material, PVD is carried out on the electroplated layer to obtain the first PVD layer, PVD is carried out on the transition layer to obtain the second PVD layer, the interface between the alloy electroplated layer and the first PVD layer is a coherent interface or a semi-coherent interface, the prepared aluminum alloy component with the electroplated layer is high in film bonding force, good in wear resistance and scratch resistance, attractive in highlight appearance effect, simple in process and low in production cost.

In one possible implementation of this aspect, a coherent or semi-coherent interface is formed between the first PVD layer and the second PVD layer.

In one possible implementation of this aspect, the first PVD layer includes a first metal element that is the same as or has the same lattice type as a largest mass percentage of metal elements in the alloy electroplated layer.

In one possible implementation manner of this aspect, the first PVD layer further includes a second metal element, and the second metal element is the same as or has the same lattice type as the base metal element in the second PVD layer.

In one possible implementation manner of this aspect, the preparing the first PVD layer on the alloy electroplated layer by a PVD method includes: preparing a first sub-transition layer on the alloy electroplated layer by a PVD method, wherein the composition of the first sub-transition layer is the first metal element; preparing a second sub-transition layer on the first sub-transition layer by a PVD method, wherein the composition of the second sub-transition layer is the first metal element and the second metal element; and preparing a third sub-transition layer on the second sub-transition layer by a PVD method, wherein the composition of the third sub-transition layer is the second metal element, and the first sub-transition layer, the second sub-transition layer and the third sub-transition layer form the first PVD layer.

In one possible implementation manner of this aspect, the method further includes: and carrying out at least one of finish milling and polishing on the original aluminum alloy material to obtain the aluminum alloy base material to be electroplated. The treatment in the possible implementation mode is consistent with the pretreatment of the existing anode oxidation scheme, and the thickness of the aluminum alloy base material can be reduced through at least one of finish milling, polishing and the like, and a smoother and smoother surface can be obtained, so that the surface of the aluminum alloy base material can be conveniently electroplated.

In one possible implementation manner of this aspect, the method further includes: and carrying out alkaline etching on the original aluminum alloy material to obtain the aluminum alloy base material to be electroplated.

In one possible implementation of this aspect, the original aluminum alloy material is a defective product resulting from anodization. The original aluminum alloy material in this possible implementation may be a defective product produced by anodization to remove the anodized layer. The existing anode oxidation scheme may cause high defect rate due to uneven crystal grains or structures of the original aluminum alloy material. The surface treatment method of possible realization mode for the defective product can obviously reduce the production cost of manufacturers.

In one possible implementation of this aspect, the electroplating method includes at least one of a pretreatment of acid washing, alkali washing, inorganic salt soaking, and zinc precipitation. In this possible implementation, the pretreatment can improve the plating adhesion and stability of the electroplated layer.

In one possible implementation manner of this aspect, before the preparing the first PVD layer on the alloy electroplated layer by the PVD method, the method further includes: and polishing the aluminum alloy component with the alloy electroplated layer. In this possible implementation, to the condition that the aluminum alloy substrate is die-cast aluminum alloy substrate, can carry out polishing treatment to the aluminum alloy component that has the alloy plating layer and obtain smooth plane to carry out subsequent PVD and handle, perhaps if introduced orange line in the electroplating process, also can polish before carrying out PVD and eliminate orange line.

In one possible implementation manner of this aspect, before the preparing the first PVD layer on the alloy electroplated layer by the PVD method, the method further includes: the aluminum alloy member having the alloy plating layer is subjected to at least one of physical cleaning and chemical cleaning. The physical cleaning and the chemical cleaning are carried out on the aluminum alloy component with the alloy electroplated layer in the possible realization mode, and the plating binding force and the stability of the electroplated layer can be improved.

There are some possible implementation manners in this aspect, which may be consistent with the possible implementation manners in the previous aspect, and the obtained beneficial effects are also consistent with the possible implementation manners in the previous aspect, and are not described in detail herein.

Drawings

Fig. 1 is a schematic view of a mobile phone member to which the surface treatment method of the present embodiment is applied.

Fig. 2 is a schematic flowchart of a surface treatment method according to an embodiment of the present embodiment.

FIG. 3 is a schematic view of an aluminum alloy member with a plating layer according to an embodiment of the present embodiment.

Fig. 4 is a schematic view of an aluminum alloy member having a plating layer according to another embodiment of the present embodiment.

Detailed Description

The technical solution in the present embodiment will be described below with reference to the accompanying drawings.

First, several concepts related to the present embodiment will be described.

Electroplating (Electroplating) is a process of plating a thin layer of other metals or alloys on the surface of some metals by using the principle of electrolysis, and is a process of attaching a metal film on the surface of a metal or other material product by using the action of electrolysis, thereby playing roles of preventing metal oxidation (such as generating rust), improving wear resistance, conductivity, light reflection, corrosion resistance (such as generating copper sulfate and the like), enhancing the appearance and the like. The types of the electroplated coating include a single-layer metal electroplated coating, a binary alloy electroplated coating, a ternary alloy electroplated coating and the like.

Physical Vapor Deposition (PVD) is a technique of vaporizing the surface of a material source (solid or liquid) into gaseous atoms, molecules or partially ionized into ions by a Physical method under vacuum, and depositing a thin film with a specific function on the surface of a substrate by a low-pressure gas (or plasma) process. The main PVD methods include vacuum evaporation, sputter coating, arc plasma coating, ion coating, molecular beam epitaxy, and the like.

The composition gradient transition layer is a composition gradient transition layer formed by selecting two (or more) materials with different compositions and changing the compositions of the two (or more) materials in a gradient manner.

The coherent interface means that atoms on the two-phase interface are completely matched in a one-to-one correspondence manner, namely the atoms on the interface are simultaneously positioned on nodes of two-phase lattices and are shared by two adjacent crystals.

The semi-coherent interface means that the distance between two adjacent crystal grain surfaces on two interfaces has a large difference, atoms on the interfaces are not completely in one-to-one correspondence, some crystal surfaces have a corresponding relation, and other crystal surfaces have no corresponding relation.

The composition gradient transition layer, the coherent interface and the semi-coherent interface will be described in detail below with reference to specific examples of this embodiment.

In addition to the anode oxidation scheme for forming a high-brightness appearance on the surface of the aluminum alloy, the existing scheme is to perform PVD on the surface of the aluminum alloy directly. Namely, PVD is directly performed on the surface of the profile aluminum alloy base material or the die-cast aluminum alloy base material to obtain an effect similar to PVD performed on the surface of stainless steel. This solution has the following problems: (1) the aluminum alloy belongs to active metal, a nanoscale aluminum oxide layer is very easily formed on the surface (even if pretreatment is carried out, the nanoscale aluminum oxide layer cannot be avoided), the aluminum oxide layer is easily combined with the PVD layer to form the weak point of a coating, the problems of bulging, falling-off and the like of the PVD layer are caused, and the problem of poor appearance is solved. (2) The aluminum alloy base material is softer, and after the PVD is directly carried out, the reliability of the film layer is poor, and the problem of scratching or paint falling is easily caused.

The existing proposal is to carry out PVD after the conventional electroplating on the surface of the aluminum alloy base material. Conventional electroplating generally includes two of the following: (1) single-layer unit electroplating: electroplating single-layer unit Ni or Cr. (2) Multilayer unit electroplating: the electroplating elements are unit film layers of Cu, Ni, Cr and the like, and at least two layers are electroplated by matching the unit film layers. For single layer cell plating, the plating performance is limited by the performance deficiencies of the cell and the film properties of the cell. For example, in the nickel layer, the mismatching degree of the Ni element and the surface of the aluminum alloy is high, the stress of the film layer is large, the nickel plating yield is low, the yield loss of the rear-section material causes high cost, and the Ni layer has the problem of nickel release, causes skin diseases and is not suitable for electronic consumer products. And for example, the chromium layer can be specifically divided into decorative chromium and hard chromium, the decorative chromium film layer is thin (only about 1 um), the wear resistance and scratch resistance of the PVD layer are poor, the hard chromium has environmental protection hidden dangers, the surface of the hard chromium has microcracks, the appearance glossiness is insufficient, the performance of the PVD layer is affected, and the scratch or paint dropping problem is easy to occur. For multi-layer unit electroplating, the multi-layer electroplating increases the amount of bath solution, prolongs the processing time, has low efficiency and high cost, and has high difficulty (large tolerance) in controlling the thickness of the film layer. The more film layers, the greater the regulatory risk.

The embodiment provides an aluminum alloy member with a plating layer and a surface treatment method, wherein a PVD layer with high bonding force and excellent performance is formed on the surface of an aluminum alloy base material, and a high-brightness appearance effect which is the same as or better than that of the PVD layer plated on the surface of a stainless steel base material is obtained.

The surface treatment method of the embodiment can be applied to the appearance piece of the terminal equipment. In other words, the aluminum alloy member with a plated layer of the present embodiment can be used as an exterior member of a terminal device. It should be understood that the terminal equipment of the present embodiment may be a mobile terminal, such as a mobile phone (e.g., "cellular" phone) and a computer with mobile characteristics, such as a portable, pocket, hand-held or car-mounted mobile device, and the present embodiment is not limited thereto. Specifically, the terminal device may be a mobile phone, a notebook computer, a tablet computer, smart glasses, or a smart bracelet, etc. The appearance piece of the terminal device may include a metal rear cover, a metal middle frame, and a metal card holder of the mobile phone, a metal rear cover, a metal middle frame, and a metal card holder of the tablet computer, an appearance piece of the smart phone, and the like, which is not limited in this embodiment.

Fig. 1 is a schematic view of a mobile phone member to which the surface treatment method of the present embodiment is applied. In the smart phone 10 shown in fig. 1, the smart phone 10 includes a phone bezel 110 and a phone back cover 120.

Fig. 2 is a schematic flow chart of a surface treatment method 200 according to an embodiment of the present embodiment. As shown in fig. 2, the method 200 may include the following steps.

S210, preparing an alloy electroplated layer on the surface of the aluminum alloy base material by an electroplating method.

And S220, preparing a first PVD layer on the alloy electroplated layer by a Physical Vapor Deposition (PVD) method.

And S230, preparing a second PVD layer on the first PVD layer through a PVD method to obtain the aluminum alloy component with the plated layer, wherein a coherent interface or a semi-coherent interface is formed between the alloy plated layer and the first PVD layer.

According to the surface treatment method, the alloy electroplated layer is electroplated on the aluminum alloy base material, the PVD is carried out on the electroplated layer to obtain the first PVD layer, the PVD is carried out on the transition layer to obtain the second PVD layer, the interface between the alloy electroplated layer and the first PVD layer is a coherent interface or a semi-coherent interface, the prepared aluminum alloy component with the electroplated layer is high in film bonding force, good in wear resistance and scratch resistance, attractive in highlight appearance effect, simple in process and low in production cost.

It is to be understood that in various embodiments, the first PVD layer may be considered a PVD transition layer; the second PVD layer may be considered a PVD color layer.

It is also understood that in various embodiments, the first PVD layer may be a compositional gradient transition layer.

The coherent or semi-coherent interface may ensure a high bonding force between the layers, and thus in various embodiments, it is desirable to form a coherent or semi-coherent interface between the alloy electroplated layer and the first PVD layer.

It should be understood that in the step S210 of this embodiment, a single-layer alloy plating layer may be electroplated, and a multi-layer alloy plating layer may also be electroplated. The electroplated layer can be a unit metal electroplated layer, a unit alloy electroplated layer or a multi-component alloy electroplated layer. Hereinafter, a single-layer multi-alloy plating layer is mainly used as an example for the plating. Herein, if the plating layer has more than one metal element but the metal elements other than the main metal element are less contained, it may be referred to as a unit alloy plating layer. The unit alloy plating layer and the multi-alloy plating layer will be described in detail below.

Similarly, in some embodiments, it may also be desirable to form a coherent or semi-coherent interface between the first PVD layer and the second PVD layer.

Wherein the first PVD layer comprises a first metal element, and the first metal element is the same as or has the same lattice type with the metal element with the largest mass percentage in the alloy electroplated layer. Further, the first metal element may have a different lattice type from that of the metal element having the largest mass percentage in the alloy plating layer, but the first metal element may have a similar lattice constant to that of the metal element having the largest mass percentage in the alloy plating layer. The first metal element meeting the conditions can generally form a coherent interface or a semi-coherent interface between the alloy electroplated layer and the first PVD layer, so that the film bonding force of the prepared aluminum alloy member with the electroplated layer can be improved.

Optionally, the first PVD layer may further include a second metal element, and the second metal element is the same as or has the same lattice type as the base metal element in the second PVD layer. The second metal element meeting the above conditions can generally form a coherent interface or a semi-coherent interface between the first PVD layer and the second PVD layer, which can improve the bonding force of the prepared aluminum alloy member film layer with the plating layer.

The aluminum alloy substrate of the present embodiment may be a profile aluminum alloy substrate, for example, a profile aluminum alloy substrate obtained by stamping or a profile aluminum alloy substrate obtained by CNC processing. Specifically, the profile aluminum alloy substrate can include, but is not limited to, a 5, 6, 7 series aluminum alloy substrate made by stamping, forging, melting, extruding, rolling, calendering, and the like. The aluminum alloy base material of the present embodiment may be a die-cast aluminum alloy base material. The die-cast aluminum alloy substrate may include, but is not limited to, aluminum alloy substrates made by a die-casting process, gravity casting, semi-solid casting, or the like. The surface treatment method of the present embodiment may be applied to a substrate made of a material other than aluminum alloy, but the present embodiment is not limited thereto.

Optionally, as an embodiment, before S210, the method 200 may further include a step of shaping the aluminum alloy substrate, by combining one or more of the above processes, to obtain the aluminum alloy substrate to be treated.

Optionally, as an embodiment, before S210, the method 200 may further include pretreating the aluminum alloy base material. For example, the original aluminum alloy material may be subjected to at least one of finish milling and polishing to obtain an aluminum alloy base material to be plated. The treatment is consistent with the pretreatment of the prior anode oxidation scheme, and the thickness of the aluminum alloy base material can be reduced through at least one of finish milling, polishing and the like, and a smoother and smoother surface can be obtained, so that the surface of the aluminum alloy base material can be conveniently electroplated.

For another example, the original aluminum alloy material may be subjected to alkali etching to obtain an aluminum alloy base material to be plated. The alkaline etching can be performed in the following two cases. In one case, the original aluminum alloy material is a defective product produced by anodizing to remove the anodized layer. The existing anode oxidation scheme may cause high defect rate due to uneven crystal grains or structures of the original aluminum alloy material. The surface treatment method of the embodiment can obviously reduce the production cost of manufacturers. In another case, the thickness of the film layer generated by the subsequent electroplating and PVD process is thicker, so that the metal layer of the original aluminum alloy material is uniformly corroded by 10-15 microns.

It should be understood that several of the above-listed pretreatments are optional steps, and that no pretreatment, or one or more pretreatments, may actually be performed as desired.

Alternatively, as an example, the plating method in S210 may include at least one of a pre-treatment of an acid washing treatment, a caustic washing treatment, an inorganic salt soaking treatment, and a zinc precipitation treatment. The pretreatment can improve the coating binding force and stability of the electroplated coating.

Specifically, at least one of physical cleaning and chemical cleaning (for example, acid cleaning, alkali cleaning, and inorganic salt soaking) may be performed on the original aluminum alloy material to remove the physical adsorption and chemical adsorption stains on the surface of the original aluminum alloy material, so as to obtain a clean surface of the aluminum alloy substrate, thereby facilitating electroplating on the surface of the aluminum alloy substrate.

In addition, the original aluminum alloy material can be subjected to zinc precipitation treatment. The zinc deposition treatment belongs to the conventional pretreatment operation of electroplating and is used for isolating the aluminum alloy substrate and the electroplating solution and preventing the aluminum alloy substrate and the electroplating solution from generating chemical reaction. It is understood that the zinc deposition treatment of the pre-plating treatment will produce a zinc deposited layer having a thickness of no more than 100 nm. The zinc layer is not easy to detect, the number of electroplating layers is not counted, and the electroplating layer of the embodiment is only one.

Alternatively, as an example, the alloy plating layer obtained by plating in the surface treatment method 200 of the present embodiment may have a composition of a binary alloy or a ternary alloy. It is understood that in various embodiments, the multi-component alloy may be defined in terms of composition content. The content of main metal elements of the binary alloy, namely the metal elements with the largest mass percentage is not higher than 99.5 percent. Specifically, for example, if the content of the main metal element in the plating layer is more than 99.7%, the plating layer is a unit alloy; if the content of the main metal element of the coating is 99.5 percent and the content of the other metal element is 0.5 percent, the coating is a binary alloy. In the ternary alloy of each example, the content of the first main element, i.e., the largest metal element by mass percentage, is not higher than 99.5%, the content of the second main element, i.e., the second largest metal element by mass percentage, may be less than 0.5%, and the content of the smallest metal element by mass percentage is not lower than 0.1%.

The alloy electroplated layer of the embodiment can avoid elements such as Cr and the like which have environmental protection or health hidden troubles as much as possible. For example, the binary alloy of the alloy plating layer of the present embodiment may include CuSn alloy, NiP alloy, CuZn alloy, FeZn alloy, ZnNi alloy, ZnTi alloy, SnCe alloy, or the like, and the ternary alloy includes CuSnZn alloy, SnCoZn alloy, SnNiZn alloy, SnNiCo alloy, or the like. The binary alloy or the ternary alloy has high glossiness, has good bonding performance with an aluminum alloy base material, does not need other plating layer priming and surface brightening, and has excellent wear resistance. In the present embodiment, the thickness of the alloy plating layer is generally greater than or equal to 0.5 micrometers and less than or equal to 50 micrometers.

It should be understood that in the present embodiment, the composition of the alloy plating layer may be a quaternary alloy or a higher alloy. The alloy plating layer may contain other metal elements than Cu, Sn, Zn, Ni, P, Fe, Ti, Ce, Co, etc., and these metal elements may form a multi-alloy plating layer in an appropriate ratio. The thickness of the alloy plating layer can be adjusted according to actual needs, for example, the thickness is greater than 30 micrometers, which is not limited in this embodiment.

Optionally, as an embodiment, before the step S220 of preparing the first PVD layer on the alloy plating layer by a PVD method, the method 200 may further include: and polishing the aluminum alloy component with the alloy electroplated layer. Specifically, in the case where the aluminum alloy base material is a die-cast aluminum alloy base material, the aluminum alloy member having the alloy plating layer may be subjected to a PVD treatment after being subjected to a polishing treatment. This is because pores are easily generated in the die-cast aluminum alloy base material, and these pores cause uneven thickness of the alloy plating layer formed during plating, so that the aluminum alloy member having the alloy plating layer can be subjected to polishing treatment to obtain a flat surface, thereby facilitating subsequent PVD treatment. If the alloy plating layer obtained after the plating is thick, the aluminum alloy member having the alloy plating layer may also be subjected to a polishing treatment to reduce the thickness of the alloy plating layer. In addition, if orange peel is introduced during the electroplating process, the orange peel can be removed by polishing before PVD.

Alternatively, in the plating process of S210 of the present embodiment, the plating solution may be stirred to enhance the thickness uniformity of the plated layer. The stirring of the plating solution is particularly suitable for the case where the area of the aluminum alloy substrate to be plated is large.

Optionally, as an embodiment, after S210, before preparing the first PVD layer on the alloy plating layer by the PVD method in S220, the method 200 may further include: the aluminum alloy member having the alloy plating layer is subjected to at least one of physical cleaning and chemical cleaning. The introduction of this step can remove the contamination of the surface of the aluminum alloy member due to physical adsorption and chemical adsorption caused by electroplating.

Alternatively, as an embodiment, the step S220 of preparing the first PVD layer on the alloy plating layer by a PVD method may include: preparing a first sub-transition layer on the alloy electroplated layer by a PVD method, wherein the component of the first sub-transition layer is a first metal element; preparing a second sub-transition layer on the first sub-transition layer by a PVD method, wherein the components of the second sub-transition layer are a first metal element and a second metal element; and preparing a third sub-transition layer on the second sub-transition layer by a PVD method, wherein the composition of the third sub-transition layer is a second metal element, and the first sub-transition layer, the second sub-transition layer and the third sub-transition layer form a first PVD layer.

Specifically, the steps S220 and S230 in the method 200 of the present embodiment are both PVD processing steps. The step S220 of preparing the first PVD layer is to improve the bonding force between the electroplated layer and the color layer. The PVD element, namely the first metal element, selected from the first sub-transition layer of the first PVD layer is the same as or has the same lattice type with the metal element with the largest mass percentage in the alloy electroplated layer, so that the first sub-transition layer and the alloy electroplated layer have good bonding force. A second metal element can be added in the PVD element of the second sub-transition layer of the first PVD layer besides the first metal element, and the first metal element enables the first sub-transition layer and the second sub-transition layer to have good bonding force; the second metal element is used for transition, so that a good bonding force is formed between the second sub-transition layer and the third sub-transition layer of the first PVD layer. The PVD element of the third sub-transition layer is a second metal element, and the second metal element is the same as or has the same lattice type as the basic metal element in the second PVD layer, so that the third sub-transition layer and the second PVD layer have good bonding force. Through the three sub-transition layers, good binding force between the electroplated layer and the color layer can be guaranteed.

It should be understood that the ratio of the first metal element and the second metal element in the second sub-transition layer may be any ratio, and this embodiment is not limited thereto.

It should also be understood that in this embodiment, the first PVD layer may not include the first sub-transition layer, the second sub-transition layer, and the third sub-transition layer. For example, the first PVD layer is only one layer, and has a composition of the first metal element and the second metal element. Or the first PVD layer comprises two layers, wherein one layer close to the alloy electroplated layer is composed of the first metal element and the second metal element, and the other layer close to the second PVD layer is composed of the second metal element. Or the first PVD layer comprises two layers, wherein the composition of one layer close to the alloy electroplated layer is the first metal element, and the composition of the other layer close to the second PVD layer is the first metal element and the second metal element. This embodiment is not limited to this.

Alternatively, as an embodiment, the composition of the second PVD layer may be a nitride, a carbide, an oxide, a nitrocarbide, an oxycarbide, an oxynitride, or the like of the base metal element, which is not listed in the embodiment.

Alternatively, as an embodiment, the second metal element, i.e., the base metal element of the second PVD layer, may be Ti, Cr, Au, Ag, or the like, which is not listed in this embodiment.

Optionally, in this embodiment, the total thickness of the first PVD layer and the second PVD layer is typically greater than or equal to 0.5 microns and less than or equal to 7 microns. The thickness of the PVD film can also be adjusted according to actual needs, for example, thicker than 7 microns or thinner than 0.5 micron, which is not limited in this embodiment.

FIG. 3 is a schematic view of an aluminum alloy member 300 having a plating layer according to an embodiment of the present embodiment. As shown in fig. 3, aluminum alloy component 300 can include aluminum alloy substrate 310, alloy electroplated layer 320, first PVD layer 330, and second PVD layer 340, with a coherent or semi-coherent interface formed between alloy electroplated layer 320 and first PVD layer 330. An alloy electroplated layer 320 is disposed between the aluminum alloy substrate 310 and the first PVD layer 330; the first PVD layer 330 is disposed between the aluminum alloy substrate 310 and the second PVD layer 330.

Optionally, a coherent or semi-coherent interface is also desired between first PVD layer 330 and second PVD layer 340.

Optionally, first PVD layer 330 may include a first metal element that is the same as or has the same lattice type as the largest mass percentage of metal elements in alloy electroplated layer 320. Further, the first metal element may have a different lattice type from that of the metal element having the largest mass percentage in the alloy plating layer, but the first metal element may have a similar lattice constant to that of the metal element having the largest mass percentage in the alloy plating layer.

Optionally, the first PVD layer 330 may further include a second metal element, and the second metal element may be the same as or have the same lattice type as the base metal element in the second PVD layer 340. Further, the second metal element may have a different lattice type from the base metal element in the second PVD layer, but the second metal element may have a similar lattice constant to the base metal element in the second PVD layer.

Fig. 4 is a schematic view of an aluminum alloy member 300 having a plating layer according to another embodiment of the present embodiment. Alternatively, as an example, as shown in fig. 4, in the direction from the alloy electroplated layer 320 to the second PVD layer 340, the first PVD layer 330 may sequentially include a first sub-transition layer 332, a second sub-transition layer 334, and a third sub-transition layer 336, the composition of the first sub-transition layer 332 may be a first metal element, the composition of the second sub-transition layer 334 may be a first metal element and a second metal element, and the composition of the third sub-transition layer 336 may be a second metal element.

Alternatively, as one embodiment, the composition of alloy plating layer 320 may be a binary alloy or a ternary alloy.

Alternatively, as an embodiment, the binary alloy may include CuSn alloy, NiP alloy, CuZn alloy, FeZn alloy, ZnNi alloy, ZnTi alloy, or SnCe alloy, and the ternary alloy includes CuSnZn alloy, SnCoZn alloy, SnNiZn alloy, or SnNiCo alloy.

Alternatively, as one embodiment, the thickness of the alloy plating layer may be greater than or equal to 0.5 micrometers and less than or equal to 50 micrometers.

Optionally, as an embodiment, a total thickness of the first PVD layer and the second PVD layer may be greater than or equal to 0.5 microns and less than or equal to 7 microns.

The surface treatment method of the present embodiment and the aluminum alloy member having a plated layer produced by the method will be described below with reference to several specific examples.

Example 1:

the embodiment is used for manufacturing the rear cover of the mobile phone, and specifically comprises the following steps.

The method comprises the following steps: the 5252 aluminum alloy section formed by rolling after rolling is selected as an original aluminum alloy material, and the mobile phone rear cover is obtained by stamping, CNC, injection molding and other modes and is used as an aluminum alloy base material.

Step two: polishing the appearance surface of the rear cover of the 5252 aluminum alloy mobile phone.

Step three: and (3) carrying out physical cleaning and chemical cleaning on the rear cover of the 5252 section aluminum alloy mobile phone to remove the dirt physically and chemically adsorbed on the surface.

Step four: the rear cover of the 5252 aluminum alloy mobile phone is electroplated with a single-layer Cu-Sn-Zn ternary alloy electroplated layer, the thickness of the single-layer Cu-Sn-Zn ternary alloy electroplated layer is typically 15 microns, and the Cu-Sn-Zn ternary alloy electroplated layer is stirred during electroplating to enhance the uniformity of the electroplating thickness due to the fact that the area of the rear cover of the mobile phone is large and the thickness of the Cu-Sn-Zn ternary alloy electroplated layer is possibly uneven. The mass percentages of Cu, Sn and Zn are respectively Cu60%, Sn30% and Zn 10%.

Step five: and placing the electroplated 5252 aluminum alloy mobile phone rear cover into a PVD furnace.

Step six: and starting the Cu target, and carrying out PVD (physical vapor deposition) deposition on the Cu-Sn-Zn ternary alloy electroplated layer to form a Cu layer with the thickness of 200nm to form a first sub-transition layer (the first metal element is Cu). And starting the Ti target again, and depositing Cu and Ti for 300 seconds to form a second sub-transition layer (the second metal element is Ti). And then closing the Cu target, and depositing only Ti to form a third sub-transition layer.

Step seven: and starting nitrogen while keeping the Ti target started, and depositing a TiN color layer, namely the second PVD layer.

The aluminum alloy member with a plating layer obtained in the present embodiment may include: 5252 aluminum alloy base material of the profile, Cu 60-Sn 30-Zn 10% electroplated layer, Cu film layer (first sub-transition layer), CuTi film layer (second sub-transition layer), Ti film layer (third sub-transition layer) and TiN film layer (second PVD layer).

In this example, the composition of the first PVD layer is changed from Cu to CuTi and then to Ti from the alloy electroplated layer to the second PVD layer, which can be considered as a composition gradient transition.

In this embodiment, the first sub-transition layer (Cu film layer) in the first PVD layer may be coherent with the alloy electroplated layer (Cu 60% -Sn 30% -Zn 10% electroplated layer), that is, atoms at the interface of the first sub-transition layer and the alloy electroplated layer are simultaneously located on the nodes of two-phase crystal lattices, and the formed interface is a coherent interface. The third sub-transition layer (Ti film) in the first PVD layer may be coherent with the second PVD layer (TiN film), that is, atoms on the interface between the third sub-transition layer and the second PVD layer are simultaneously located on the nodes of the two-phase crystal lattice, and the formed interface is a coherent interface.

This embodiment makes a light golden PVD effect on the cell phone back cover of calendering aluminum alloy substrate, can obtain the effect similar to performing PVD on stainless steel. The appearance effect and the performance of the mobile phone rear cover are the same as those of the steel-aluminum composite plate rear cover adopted in the market at present, and the mobile phone rear cover is light in weight. In the embodiment, the inert Cu-Sn-Zn ternary alloy electroplated layer is electroplated and then PVD is carried out, so that the industrial problem that the high-activity aluminum alloy cannot be subjected to PVD directly can be solved, and the electroplated layer has high bonding force, high corrosion resistance and scratch resistance and attractive appearance effect. Further, the embodiment is not limited to the strength, chemical composition, microstructure, and the like of the aluminum alloy base material.

Example 2:

The method comprises the following steps: a6063 aluminum alloy section which is extruded and formed is selected as an original aluminum alloy material, and a mobile phone rear cover is obtained as an aluminum alloy base material by forging, CNC, heat treatment (namely T treatment), injection molding and other modes.

Step two: and polishing the appearance surface of the back cover of the 6063 aluminum alloy mobile phone.

Step three: and (3) carrying out physical cleaning and chemical cleaning on the back cover of the 6063 aluminum alloy mobile phone so as to remove the dirt physically and chemically adsorbed on the surface.

Step four: the back cover of the 6063 aluminum alloy mobile phone is subjected to electroless plating of a single-layer Ni-P binary alloy plating layer, the thickness of the single-layer Ni-P binary alloy plating layer is typically 20 microns, and due to the fact that the area of the back cover of the mobile phone is large, the Ni-P binary alloy plating layer may have uneven thickness, and the plating solution is stirred during the plating process to enhance the plating thickness uniformity. The mass percentages of Ni and P are Ni90% and P10%, respectively.

Step five: and (3) carrying out physical cleaning and chemical cleaning on the back cover of the 6063 aluminum alloy mobile phone with the single-layer Ni-P binary alloy electroplated layer to remove the dirt physically adsorbed and chemically adsorbed on the surface in the electroplating process.

Step six: and (4) putting the treated 6063 aluminum alloy mobile phone rear cover into a PVD furnace.

Step seven: and starting the Ti target, and carrying out PVD (physical vapor deposition) deposition on the Ni-P binary alloy coating to form a Ti layer with the thickness of 200nm to form a first sub-transition layer (the first metal element is Ti). And opening the nitrogen again to deposit TiN (second sub-transition layer), and then closing the Ti target and the nitrogen to deposit Au-Ag-Cu (18K gold) to form a third sub-transition layer.

Step eight: and closing the Ag target and the Cu target, keeping the Au target open, and simultaneously opening nitrogen to deposit AuN color layers, namely the second PVD layer.

The aluminum alloy member with a plating layer obtained in the present embodiment may include: the alloy material comprises a 6063 section aluminum alloy base material, Ni90% -P10% of electroplated layer, a Ti film layer (a first sub-transition layer), a TiN film layer (a second sub-transition layer), an Au-Ag-Cu film layer (a third sub-transition layer) and a AuN film layer (a second PVD layer).

In this embodiment, the first sub-transition layer (Ti film layer) in the first PVD layer may be semi-coherent with the alloy plating layer (Ni 90% -P10% plating layer), that is, a part of the crystal planes of the interface between the first sub-transition layer and the alloy plating layer is in a corresponding relationship, and the formed interface is a semi-coherent interface. The third sub-transition layer (Au-Ag-Cu film layer) in the first PVD layer may be coherent with the second PVD layer (AuN film layer), i.e. atoms at the interface of the third sub-transition layer and the second PVD layer are simultaneously located at nodes of two-phase lattice, and the formed interface is coherent interface.

In the embodiment, the PVD color film with higher yield is manufactured on the rear cover of the mobile phone extruded with the aluminum alloy base material. The wear resistance and the scratch resistance of the product can meet the requirements of PVD treatment test on stainless steel. The surface of the extruded section aluminum alloy base material generally has a fine crystal layer about 0.3 mm, and if the original material is forged and pressed, grains severely deformed in subsequent heat treatment grow abnormally, and poor appearance is introduced. If the original material is not forged, the short straight edge is positioned at different layer depths, and the appearance approaches the center, so that the conditions of heterochrosis and fogging are easy to occur. After the surface treatment of the embodiment, the consistency of the mobile phone rear cover is good. Moreover, the Ni-P binary alloy electroplated layer has high glossiness and good bonding performance with a base material, does not need other plating layer priming and surface brightening, and has more excellent wear resistance.

Example 3:

the embodiment is used for manufacturing the frame piece in the mobile phone, and specifically comprises the following steps.

The method comprises the following steps: and selecting the 6013 aluminum alloy section after extrusion forming as an original aluminum alloy material, and obtaining the mobile phone middle frame piece as an aluminum alloy base material by forging, CNC (computerized numerical control), T treatment, injection molding and other modes.

Step two: and carrying out finish milling on the 6013 section bar aluminum alloy mobile phone middle frame piece.

Step three: and (3) carrying out physical cleaning and chemical cleaning on the 6013 section bar aluminum alloy mobile phone middle frame piece to remove the surface physical adsorption and chemical adsorption stains.

Step four: and (3) carrying out alkaline etching on the 6013 section bar aluminum alloy mobile phone middle frame, and corroding the metal layer by 10-15 microns.

Step five: and (3) carrying out single-layer Cu-Sn-Zn ternary alloy electroplated layer electroplating operation on the 6013 section bar aluminum alloy mobile phone middle frame, wherein the thickness of the single-layer Cu-Sn-Zn ternary alloy electroplated layer is typically 15 microns. The mass percentages of Cu, Sn and Zn are respectively Cu50%, Sn30% and Zn 20%.

Step six: and (3) carrying out physical cleaning and chemical cleaning on the 6013 section aluminum alloy mobile phone middle frame with the single-layer Cu-Sn-Zn ternary alloy electroplated layer so as to remove the surface physical adsorption and chemical adsorption dirt in the electroplating process.

Step seven: and putting the treated 6013 section aluminum alloy mobile phone middle frame piece into a PVD furnace.

Step eight: and starting the Cu target, and carrying out PVD (physical vapor deposition) deposition on the Cu-Sn-Zn ternary alloy electroplated layer to form a Cu layer with the thickness of 200nm to form a first sub-transition layer (the first metal element is Cu). And starting the Ti target again, and depositing Cu and Ti for 300 seconds to form a second sub-transition layer (the second metal element is Ti). And then closing the Cu target, and depositing only Ti to form a third sub-transition layer.

Step nine: and starting nitrogen while keeping the Ti target started, and depositing a TiN color layer, namely the second PVD layer.

The aluminum alloy member with a plating layer obtained in the present embodiment may include: 6013 section bar aluminum alloy base material + Cu 50-Sn 30-Zn 20% electroplated layer + Cu film layer (first sub-transition layer) + CuTi film layer (second sub-transition layer) + Ti film layer (third sub-transition layer) + TiN film layer (second PVD layer).

In this embodiment, the first sub-transition layer (Cu film layer) in the first PVD layer may be semi-coherent with the alloy electroplated layer (Cu 50% -Sn 30% -Zn 20% electroplated layer), that is, the first sub-transition layer and a part of the crystal planes of the interface of the alloy electroplated layer are in corresponding relationship, and the formed interface is a semi-coherent interface. The third sub-transition layer (Ti film) in the first PVD layer may be semi-coherent with the second PVD layer (TiN film), that is, a part of crystal planes of the interface between the third sub-transition layer and the second PVD layer are in corresponding relationship, and the formed interface is a semi-coherent interface.

The embodiment has a black PVD effect on the mobile phone middle frame piece made of the aluminum alloy section material, and can obtain an effect similar to PVD on stainless steel. The appearance glossiness of the middle frame of the mobile phone is superior to the aluminum alloy highlight anodic oxidation appearance. The good surface foundation is provided for the 6013 section aluminum alloy base material through electroplating, so that the aluminum alloy not only has the appearance effect of stainless steel, but also has the film performance similar to that of PVD (physical vapor deposition) on the stainless steel. The appearance area of the mobile phone middle frame piece is smaller than that of the mobile phone rear cover, but the mobile phone middle frame piece needs to be matched with glass, a matching transition area is a part which is stressed seriously, a film layer is easy to fall off and scratch, and the high-probability risk is also caused in the highlight anodic oxidation process. The scheme of the embodiment adopts the Cu-Sn-Zn ternary alloy electroplated layer, and the surface of the electroplated layer has high glossiness, good appearance and excellent scratch and abrasion resistance.

Example 4:

The method comprises the following steps: the 6013 aluminum alloy after extrusion forming is selected as an original aluminum alloy material, a mobile phone middle frame piece is obtained by CNC (computerized numerical control), injection molding and other modes, the mobile phone middle frame piece is subjected to anodic oxidation, and a defective product can be generated in the anodic oxidation process.

Step two: and (3) carrying out chemical methods such as alkaline etching and the like on the defective product subjected to anodic oxidation to remove the surface anodic oxidation layer, so as to obtain the 6013 profile aluminum alloy mobile phone middle frame piece to be electroplated.

Step four: the 6013 section bar aluminum alloy mobile phone middle frame piece is electroplated with a single-layer Sn-Co-Zn ternary alloy electroplated layer, the thickness of the single-layer Sn-Co-Zn ternary alloy electroplated layer is typically 15 microns, and electroplating solution can be stirred in the electroplating process to enhance the uniformity of the electroplating thickness. The mass percentages of Sn, Co and Zn are respectively Sn55%, Co25% and Zn 20%.

Step five: and (3) carrying out physical cleaning and chemical cleaning on the 6013 section aluminum alloy mobile phone rear cover with the single-layer Sn-Co-Zn ternary alloy electroplated layer to remove the surface physical adsorption and chemical adsorption dirt in the electroplating process.

Step six: and putting the treated 6013 section aluminum alloy mobile phone middle frame piece into a PVD furnace.

Step seven: and starting the Sn target, and carrying out PVD deposition on the Sn-Co-Zn ternary alloy electroplated layer to form a Sn layer with the thickness of 200nm to form a first sub-transition layer (the first metal element is Sn). And starting the Ti target again, and depositing Sn and Ti for 300 seconds to form a second sub-transition layer (the second metal element is Ti). And then, turning off the Sn target, and depositing only Ti to form a third sub-transition layer.

Step eight: and starting nitrogen while keeping the Ti target started, and depositing a TiN color layer, namely the second PVD layer.

The aluminum alloy member with a plating layer obtained in the present embodiment may include: 6013 section bar aluminum alloy base material + Sn 55-Co 25-Zn 20% electroplated layer + Sn film layer (first sub-transition layer) + SnTi film layer (second sub-transition layer) + Ti film layer (third sub-transition layer) + TiN film layer (second PVD layer).

In this embodiment, the first sub-transition layer (Sn film layer) in the first PVD layer may be semi-coherent with the alloy electroplated layer (Sn 55% -Co 25% -Zn 20%) in a corresponding relationship with a portion of the crystal planes of the interface of the alloy electroplated layer, and the formed interface is a semi-coherent interface. The third sub-transition layer (Ti film) in the first PVD layer may be semi-coherent with the second PVD layer (TiN film), that is, a part of crystal planes of the interface between the third sub-transition layer and the second PVD layer are in corresponding relationship, and the formed interface is a semi-coherent interface.

The mobile phone middle frame piece of the embodiment can achieve the appearance effect of performing PVD on stainless steel. After the verification, the surface brightness of the sample piece can be normally polished without polishing treatment containing machining property after deplating treatment (removing the anodic oxidation layer). The scheme of this embodiment has avoided scrapping because of the unqualified defective products of anodic oxidation that causes of substrate, when improving surface quality, the cost of scrapping that can greatly reduced anodic oxidation harmfully arouses. The Sn-Co-Zn ternary alloy has the wear resistance of hard chromium, and simultaneously has no problems of appearance, corrosion resistance and the like caused by the vertical cracks of the hard chromium.

Example 5:

The method comprises the following steps: ADC12 (No. 12 aluminum material) is selected to be die-cast into an aluminum alloy base material to obtain the rear cover of the mobile phone, and the rear cover is used as the aluminum alloy base material.

Step two: and polishing the appearance surface of the rear cover of the ADC12 die-cast aluminum alloy mobile phone.

Step three: and (3) carrying out electroplating operation on the ADC12 die-cast aluminum alloy mobile phone rear cover by using a single-layer Cu-Sn binary alloy electroplating layer, wherein the thickness of the single-layer Cu-Sn binary alloy electroplating layer is typically 20 microns, and in view of the large area of the mobile phone rear cover, the thickness of the Cu-Sn binary alloy electroplating layer can be uneven, and the electroplating solution is stirred in the electroplating process to enhance the electroplating thickness uniformity. The mass percentages of Cu and Sn are respectively Cu70% and Sn 30%.

Step four: polishing the appearance surface of the ADC12 die-casting aluminum alloy mobile phone rear cover with a single-layer Cu-Sn binary alloy electroplated layer.

Step five: and (3) carrying out physical cleaning and chemical cleaning on the polished ADC12 die-cast aluminum alloy mobile phone rear cover so as to remove the surface physical adsorption and chemical adsorption dirt in the electroplating process.

Step six: and (3) putting the processed ADC12 die-cast aluminum alloy mobile phone rear cover into a PVD furnace.

Step seven: and starting the Cu target, and carrying out PVD (physical vapor deposition) deposition on a Cu-Sn binary alloy electroplated layer to form a Cu layer with the thickness of 200nm to form a first sub-transition layer (the first metal element is Cu). And starting the Cr target again, and depositing Cu and Cr for 300 seconds to form a second sub-transition layer (the second metal element is Cr). And then closing the Cu target, and depositing only Cr to form a third sub-transition layer.

Step eight: and starting the C target while keeping the Cr target started to deposit a CrC color layer, namely a second PVD layer.

The aluminum alloy member with a plating layer obtained in the present embodiment may include: ADC12 die-casting aluminum alloy base material + Cu70% -Sn 30% electroplated layer + Cu film layer (first sub-transition layer) + CuCr film layer (second sub-transition layer) + Cr film layer (third sub-transition layer) + CrC film layer (second PVD layer).

In this embodiment, the first sub-transition layer (Cu film layer) in the first PVD layer may be coherent with the alloy electroplated layer (Cu 70% -Sn 30% electroplated layer), that is, the first sub-transition layer and a part of the crystal plane of the interface of the alloy electroplated layer are in corresponding relationship, and the formed interface is a semi-coherent interface. The third sub-transition layer (Cr film layer) in the first PVD layer may be semi-coherent with the second PVD layer (CrC film layer), that is, a part of crystal planes of the interface between the third sub-transition layer and the second PVD layer are in corresponding relationship, and the formed interface is a semi-coherent interface.

The embodiment performs surface treatment on the mobile phone rear cover of the die-cast aluminum alloy base material, can obtain the effect similar to PVD (physical vapor deposition) on stainless steel, and has the advantages of high plating layer binding force, strong corrosion resistance and scratch resistance, attractive appearance effect, high production efficiency and low production cost.

As described above, only the specific implementation manner of the present embodiment is provided, but the protection scope of the present embodiment is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope disclosed in the present embodiment, and all should be covered within the protection scope of the present embodiment. Therefore, the protection scope of the present embodiment shall be subject to the protection scope of the claims.

Claims

1. A surface treatment method characterized by comprising:

selecting extruded 6063 section aluminum alloy as an original aluminum alloy material, and obtaining the rear cover of the mobile phone as an aluminum alloy base material by using forging, numerical control (CNC) machine tool, heat treatment and injection molding modes;

polishing the appearance surface of the 6063 aluminum alloy mobile phone rear cover;

carrying out physical cleaning and chemical cleaning on the back cover of the 6063 aluminum alloy mobile phone to remove the dirt physically adsorbed and chemically adsorbed on the surface;

carrying out electroless plating on the back cover of the 6063 aluminum alloy mobile phone, wherein the thickness of the single-layer Ni-P binary alloy plating layer is 20 microns, stirring the plating solution in the plating process to enhance the uniformity of the plating thickness, and the mass percentages of Ni and P are Ni90% and P10%, respectively;

carrying out physical cleaning and chemical cleaning on the 6063 section aluminum alloy mobile phone rear cover with the single-layer Ni-P binary alloy electroplated layer so as to remove the dirt physically adsorbed and chemically adsorbed on the surface in the electroplating process;

putting the treated back cover of the 6063 aluminum alloy mobile phone section into a Physical Vapor Deposition (PVD) furnace;

starting a Ti target, carrying out PVD (physical vapor deposition) deposition on the Ni-P binary alloy coating to form a Ti layer with the thickness of 200nm to form a first sub-transition layer, starting nitrogen to deposit TiN (TiN), namely a second sub-transition layer, then closing the Ti target and the nitrogen to deposit Au-Ag-Cu, wherein Au is 18K gold, and forming a third sub-transition layer;

and closing the Ag target and the Cu target, keeping the Au target open, and simultaneously opening nitrogen to deposit AuN color layers, namely the second PVD layer.

2. A surface treatment method characterized by comprising:

selecting 6013 section aluminum alloy subjected to extrusion forming as an original aluminum alloy material, and obtaining a mobile phone middle frame piece as an aluminum alloy base material by using forging, numerical control (CNC) machine tool, heat treatment and injection molding modes;

finely milling the 6013 aluminum alloy mobile phone middle frame piece;

carrying out physical cleaning and chemical cleaning on the 6013 section bar aluminum alloy mobile phone middle frame piece to remove surface physical adsorption and chemical adsorption dirt;

performing alkaline etching on the 6013 section bar aluminum alloy mobile phone middle frame, and corroding the metal layer by 10-15 microns;

carrying out single-layer Cu-Sn-Zn ternary alloy electroplated layer electroplating operation on the 6013 section bar aluminum alloy mobile phone middle frame piece, wherein the thickness of the single-layer Cu-Sn-Zn ternary alloy electroplated layer is typically 15 micrometers, and the mass percentages of Cu, Sn and Zn are respectively Cu50%, Sn30% and Zn 20%;

carrying out physical cleaning and chemical cleaning on the 6013 section aluminum alloy mobile phone middle frame with the single-layer Cu-Sn-Zn ternary alloy electroplated layer so as to remove surface physical adsorption and chemical adsorption dirt in the electroplating process;

putting the treated 6013 section aluminum alloy mobile phone middle frame piece into a Physical Vapor Deposition (PVD) furnace;

starting a Cu target, carrying out PVD (physical vapor deposition) deposition on a Cu-Sn-Zn ternary alloy electroplated layer to form a Cu layer with the thickness of 200nm to form a first sub-transition layer, starting a Ti target, depositing Cu and Ti for 300 seconds to form a second sub-transition layer, wherein the second metal element is Ti, then closing the Cu target, and only depositing Ti to form a third sub-transition layer;

and starting nitrogen while keeping the Ti target started, and depositing a TiN color layer, namely the second PVD layer.

3. A surface treatment method characterized by comprising:

selecting an extruded 6013 section bar aluminum alloy as an original aluminum alloy material, obtaining a mobile phone middle frame piece by using a numerical control machine tool (CNC) and an injection molding mode, and carrying out anodic oxidation on the mobile phone middle frame piece, wherein a defective product is possibly generated in the anodic oxidation process;

carrying out chemical methods such as alkaline etching and the like on the defective product pair subjected to anodic oxidation to remove a surface anodic oxidation layer, and obtaining the 6013 section bar aluminum alloy mobile phone middle frame piece to be electroplated;

carrying out single-layer Sn-Co-Zn ternary alloy electroplated layer electroplating operation on the 6013 section bar aluminum alloy mobile phone middle frame piece, wherein the thickness of the single-layer Sn-Co-Zn ternary alloy electroplated layer is 15 microns, electroplating solution stirring is carried out in the electroplating process to enhance the electroplating thickness uniformity, and the mass percentages of Sn, Co and Zn are respectively Sn55%, Co25% and Zn 20%;

carrying out physical cleaning and chemical cleaning on the 6013 section aluminum alloy mobile phone rear cover with the single-layer Sn-Co-Zn ternary alloy electroplated layer so as to remove surface physical adsorption and chemical adsorption dirt in the electroplating process;

starting an Sn target, carrying out PVD (physical vapor deposition) deposition on an Sn-Co-Zn ternary alloy electroplated layer to form an Sn layer with the thickness of 200nm to form a first sub-transition layer, starting a Ti target, depositing Sn and Ti for 300 seconds to form a second sub-transition layer, wherein the second metal element is Ti, then closing the Sn target, and only depositing Ti to form a third sub-transition layer;

4. A surface treatment method characterized by comprising:

selecting 5252 section aluminum alloy subjected to rolling and calendaring molding after rolling as an original aluminum alloy material, and obtaining a mobile phone rear cover as an aluminum alloy base material by adopting stamping, CNC (computer numerical control) of a numerical control machine tool and injection molding;

polishing the appearance surface of the rear cover of the 5252 aluminum alloy mobile phone;

carrying out physical cleaning and chemical cleaning on the rear cover of the 5252 section aluminum alloy mobile phone to remove the dirt physically adsorbed and chemically adsorbed on the surface;

carrying out single-layer Cu-Sn-Zn ternary alloy electroplating operation on the rear cover of the 5252 section aluminum alloy mobile phone, wherein the thickness of the single-layer Cu-Sn-Zn ternary alloy electroplating layer is 15 microns, and stirring electroplating solution in the electroplating process to enhance the uniformity of the electroplating thickness, wherein the mass percentages of Cu, Sn and Zn are respectively Cu60%, Sn30% and Zn 10%;

placing the electroplated rear cover of the 5252 aluminum alloy mobile phone into a Physical Vapor Deposition (PVD) furnace;

and starting nitrogen while the Ti target is kept started, and depositing a TiN color layer, namely the second PVD layer.

5. A surface treatment method characterized by comprising:

selecting ADC12 to die-cast an aluminum alloy base material to obtain a rear cover of the mobile phone as the aluminum alloy base material, wherein the ADC12 is a No. 12 aluminum material;

polishing the appearance surface of the rear cover of the ADC12 die-cast aluminum alloy mobile phone;

electroplating a single-layer Cu-Sn binary alloy electroplated layer on the rear cover of the ADC12 die-cast aluminum alloy mobile phone, wherein the thickness of the single-layer Cu-Sn binary alloy electroplated layer is typically 20 microns, electroplating solution is stirred in the electroplating process to enhance the uniformity of the electroplating thickness, and the mass percentages of Cu and Sn are Cu70% and Sn30% respectively;

polishing the appearance surface of the ADC12 die-casting aluminum alloy mobile phone rear cover with the single-layer Cu-Sn binary alloy electroplated layer;

carrying out physical cleaning and chemical cleaning on the polished ADC12 die-cast aluminum alloy mobile phone rear cover to remove the surface physical adsorption and chemical adsorption dirt in the electroplating process;

putting the processed ADC12 die-cast aluminum alloy mobile phone rear cover into a Physical Vapor Deposition (PVD) furnace;

starting a Cu target, carrying out PVD (physical vapor deposition) deposition on a Cu layer with the thickness of 200nm on the Cu-Sn binary alloy electroplated layer to form a first sub-transition layer, wherein a first metal element is Cu, starting a Cr target, depositing Cu and Cr for 300 seconds to form a second sub-transition layer, wherein a second metal element is Cr, then closing the Cu target, and only depositing Cr to form a third sub-transition layer;

and starting the C target while keeping the Cr target started to deposit a CrC color layer, namely a second PVD layer.

6. An aluminium alloy member with a coating, characterized in that the aluminium alloy member with a coating is produced by a surface treatment method according to any one of the preceding claims 1-5.