CN110684954A

CN110684954A - Metal product, preparation method thereof and mobile phone rear shell

Info

Publication number: CN110684954A
Application number: CN201810723594.7A
Authority: CN
Inventors: 刘玉阳; 赵长涛
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2018-07-04
Filing date: 2018-07-04
Publication date: 2020-01-14
Anticipated expiration: 2038-07-04
Also published as: CN110684954B

Abstract

The invention relates to the field of multi-film layer materials, and discloses a metal product, a preparation method thereof and a mobile phone rear shell, wherein the metal product consists of a substrate, a metal layer, a bearing layer and a diamond-like carbon film layer which are sequentially deposited on the surface of the substrate; the base material is aluminum, aluminum alloy, titanium alloy or chromium alloy; the metal layer is a Cr layer, a Ti layer, an Al layer or an Nb layer; the bearing layer is a CrCN layer, a TiCN layer or an AlCN layer. The metal product of the invention can enhance the binding force of the diamond-like carbon film layer and the substrate and can still improve the physical and mechanical properties of the surface of the substrate.

Description

Metal product, preparation method thereof and mobile phone rear shell

Technical Field

The invention relates to the field of multilayer film materials, in particular to a metal product, a preparation method thereof and a mobile phone rear shell.

Background

Diamond-like carbon films (DLC films for short) are amorphous carbon films containing a diamond-like structure. The essential component of DLC films is carbon, and DLC films can be classified into two major groups, hydrogen-containing and hydrogen-free, due to differences in the source of carbon and the method of preparation. DLC film is a metastable long-range disordered amorphous material, the bonding mode among carbon atoms is covalent bond, and a certain number of C-H bonds are also present in the hydrogen-containing DLC film. Since 1996, research on magnetic filtration vacuum arc and deposition of DLC films is perfecting the industrial technology. Such as plasma source deposition, ion beam source deposition, twin medium frequency magnetron sputtering, vacuum cathode arc deposition, pulsed high voltage discharge, and the like. The DLC film differs in composition, structure and properties with different methods of preparation. The diamond-like carbon film as a novel hard film material has a series of excellent properties, such as high hardness, high wear resistance, high thermal conductivity, high resistivity, good optical transparency, chemical inertness and the like, can be widely applied to the fields of machinery, electronics, optics, thermodynamics, acoustics, medicine and the like, and has good application prospects.

The change of appearance is realized by coating film treatment on the surface of the aluminum alloy, but the defects of low wear resistance and hardness exist, and the physical and mechanical properties can be improved by adding a layer dlc (diamond-like film). Diamond-like carbon (DLC) is favored because of its superior properties of high hardness, low friction coefficient, high wear resistance, low thermal expansion coefficient, etc., and has many unique features over diamond films, such as simple deposition conditions at the required deposition temperature, large-area deposition, good film surface quality, etc., which may not be substituted by diamond films in some cases.

CN101374976A discloses an article having a relatively soft support material, a tie layer or tie layer system optionally applied to the support material and a relatively hard decorative layer, characterized in that an intermediate layer is provided between the support material and the decorative layer or between the tie layer or tie layer system and the decorative layer, which contains DLC at least as a main component; wherein, DLC layer; a Cr layer; the transition layer is composed of a mixture of Cr and WC; the covering layer is a W-C H layer, the supporting material is selected from the group consisting of aluminum, brass, magnesium and stainless steel, and the decorative layer is a CrCN layer.

CN101748381A discloses a method for preparing a multi-doped diamond-like carbon (DLC) film, wherein: firstly, removing a grease pollution layer on the surface of a GCr15 bearing by using an ultrasonic cleaning technology; and then depositing a Cr/CrN/CrCN/CrC gradient transition layer by using an anode layer ion source to assist direct-current magnetron sputtering, and finally synthesizing the DLC film simultaneously doped with Cr, Si and F on the Cr/CrN/CrCN/CrC gradient transition layer by using an ion beam deposition and magnetron sputtering technology.

CN103710799A discloses a self-lubricating coating ring, this self-lubricating coating ring includes the ring base member, it has Cr layer, CrN layer, CrCN layer, CrC layer and F-DLC layer to coat in proper order on the ring base member. The self-lubricating coating ring and the preparation process thereof are that a nano coating with a multi-layer composite structure and a self-lubricating function is prepared on the surface of the traditional ring, and the nano coating has high hardness, high adhesive force and corrosion resistance.

CN101365824A discloses a substrate coated with a multilayer structure comprising a tetrahedral carbon coating, in particular the invention relates to a metal substrate (11) at least partially coated with a multilayer structure. The multilayer structure comprises an intermediate layer (14) deposited on said substrate (11) and a tetrahedral carbon layer (16) deposited on said intermediate layer. The intermediate layer comprises at least one amorphous carbon layer having a young's modulus lower than 200GPa and the tetrahedral carbon layer having a young's modulus higher than 200GPa the shaped carbon layer may comprise an amorphous hydrogenated carbon (a-C: H) layer or a Diamond Like Nanocomposite (DLN) layer in order to further enhance the adhesion of the tetrahedral carbon layer to the metal substrate and/or the layered structure to the metal substrate, an additional adhesion promoting layer may be deposited on the metal substrate before the intermediate layer is deposited. The adhesion promoting layer comprises more than one layer, such as Ti or Cr layers. Alternatively, the adhesion promoting layer may comprise one or more layers selected from TiN, CrN, TiC, Cr2C3, TiON, TiCN and CrCN.

CN101081557A discloses a metal carbide/diamond-like nano multilayer film material and a preparation method thereof, wherein the metal carbide/diamond-like nano multilayer film material sequentially comprises a base material 1, a transition layer I and a nano multilayer film layer II, the transition layer I comprises a metal layer 2, a metal nitride layer 3 and a metal carbonitride layer 4, and the nano multilayer film layer II comprises an alternating metal carbide layer 5 and a diamond-like layer 6. The transition layer according to the invention comprises an adhesion-acting metal layer Me, a hardness-gradient transition-acting metal nitride layer MeN and a metal carbonitride layer MeCN. The deposited metal layer adopts Cr, Ti, Zr and the like because of good bonding force with materials such as steel, titanium alloy, hard alloy and the like; the metal nitride layers TiN, CrN, ZrN and the like and the metal carbonitride layers TiCN, CrCN, ZrCN and the like are deposited, so that the hardness gradient transition is established between the base material and the MeC/DLC multilayer film, the internal stress of the film layer is reduced, and the film/base binding force and the toughness of the film layer are improved.

However, the aluminum alloy surface in the above patent is plated with a film, which has poor film carrying capacity and large internal stress, and the poor film-substrate interface bonding force is prone to failure such as fracture and peeling under high load.

Therefore, in order to solve the problems of poor film bearing capacity, large internal stress and easy failure behaviors such as fracture and peeling under high load caused by poor film-substrate interface bonding force in the prior art when the film coating is carried out on the surface of the aluminum alloy, the research and development of the film coating (diamond-like carbon film) on the surface of the aluminum alloy are of great significance.

Disclosure of Invention

The invention aims to solve the problems that the film carrying capacity is poor, the internal stress is larger, the film-substrate interface binding force is poor, and failure behaviors such as fracture stripping and the like are easy to occur under high load in the prior art when the film is coated on the surface of the aluminum alloy, and provides a metal product, a preparation method thereof and a mobile phone rear shell.

In order to achieve the above object, a first aspect of the present invention provides a metal article, wherein the metal article is composed of a substrate, and a metal layer, a carrying layer and a diamond-like thin film layer sequentially deposited on a surface of the substrate;

wherein the base material is any one of aluminum, aluminum alloy, titanium alloy and chromium alloy;

wherein the metal layer is any one of a Cr layer, a Ti layer, an Al layer and an Nb layer;

wherein, the bearing layer is any one of a CrCN layer, a TiCN layer and an AlCN layer.

The invention provides a preparation method of the metal product, which sequentially comprises the following steps:

(1) bombarding and cleaning the base material by adopting an ion source;

(2) depositing a metal plating layer on the surface of the substrate by adopting magnetron sputtering;

(3) depositing a bearing layer on the surface of the metal layer by adopting magnetron sputtering;

(4) and depositing a diamond-like carbon film layer on the surface of the bearing layer by adopting magnetron sputtering.

The third aspect of the present invention provides a mobile phone back shell, wherein the mobile phone back shell is made of the metal product or the preparation method.

By adopting the technical scheme, the metal product can enhance the binding force of the diamond-like carbon film layer and the base material and still improve the physical and mechanical properties of the surface of the base material.

Drawings

FIG. 1 is a photomicrograph of a metal article made according to example 6 of the present invention;

FIG. 2 is a photomicrograph of a metal article made in example 2 of the present invention;

FIG. 3 is a photomicrograph of a metal article made by example 3 of the present invention;

FIG. 4 is a photomicrograph of a metal article made by example 4 of the present invention;

FIG. 5 is a schematic diagram of the amplitude P1-P6 points of the device during the vibro-friction test;

FIG. 6 is a schematic representation of the micro Vickers hardness tester testing indentation diagonal lengths L1 and L2 at multiples of 400X-500X.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The invention provides a metal product, wherein the metal product consists of a substrate, a metal layer, a bearing layer and a diamond-like carbon film layer which are sequentially deposited on the surface of the substrate;

According to the present invention, preferably, the base material is an aluminum alloy; the metal layer is a Cr layer; the bearing layer is a CrCN layer.

According to the invention, the bearing layer and the metal layer are added before the diamond-like thin film layer is plated, the effect is obviously better than that of a single-layer diamond-like thin film layer, because the single-layer diamond-like thin film layer has poor bearing capacity and large internal stress, the problem of failure behaviors such as fracture and peeling and the like easily occurs when the film-substrate interface binding force is poor under high load, and the bearing layer and the metal layer are added before the diamond-like thin film layer is plated, so that the defects can be overcome.

According to the invention, the metal layer has a transition effect, and the metal layer can play a role of good bonding force with a substrate material, so the thickness is not suitable to be too thick, and the inventor of the invention finds that: when the thickness of the metal layer is 5-30nm, the effect is good; preferably, when the thickness of the metal layer is 12-24nm, the effect is better; more preferably, the metal layer has a thickness of 15 to 20nm, which is most effective.

According to the invention, the bearing layer is used for establishing hardness gradient transition between the base material and the diamond-like carbon film layer, reducing the internal stress of the film layer, and improving the bonding force between the bearing layer and the diamond-like carbon film layer and the toughness of the film layer, so that the thickness is not too thick, and the inventor of the invention finds that: when the thickness of the bearing layer is 20-80nm, the effect is good; preferably, when the thickness of the bearing layer is 30-60nm, the effect is better; more preferably, the support layer has a thickness of 35-40nm, which is most effective.

According to the invention, the thickness of the diamond-like carbon film layer is controlled, so that the bonding force between the diamond-like carbon film layer and the substrate can be enhanced, and the physical and mechanical properties of the surface of the substrate can be still improved; the inventors of the present invention found that: when the thickness of the diamond-like carbon film layer is 100-160nm, the effect is good; preferably, the diamond-like carbon film layer has a thickness of 120-150nm, so that the effect is better; more preferably, the diamond-like thin film layer has the best effect when the thickness is 130-140 nm.

According to the present invention, the inventors of the present invention have unexpectedly found that: the metal layer, the bearing layer and the diamond-like carbon film layer are sequentially deposited on the surface of the base material, and the film layers are mutually synergistic, so that the binding force of the diamond-like carbon film layer and the base material can be enhanced, and the physical and mechanical properties of the surface of the base material can still be improved.

According to the present invention, the inventors of the present invention found that: the distribution of the Cr content in the bearing layer can be achieved by varying the sputtering power of a metal target (e.g., Cr target) and a graphite target (e.g., carbon target) and varying the content of nitrogen.

According to the invention, the content of the metal Cr in the bearing layer is non-uniformly distributed.

Also, the inventors of the present invention have unexpectedly found that: the content of the metal Cr in the surface layer of the bearing layer in contact with the metal layer is high, and when the content of the metal Cr in the surface layer of the bearing layer in contact with the diamond-like carbon film layer is low, the bonding force between the diamond-like carbon film layer and the base material can be enhanced, and the physical and mechanical properties of the surface of the base material can still be improved.

Preferably, the content of the metal Cr in the surface layer of the bearing layer in contact with the metal layer is A₁Metal in the surface layer of the bearing layer contacting with the diamond-like carbon film layerThe content of Cr is A₂Said A is₁Than the A₂The height is 15-45%.

According to the invention, A is₁The content of metal Cr in the surface layer of the bearing layer with the thickness of 10-40nm, which is in contact with the metal layer, is shown in the specification₂The content of metal Cr in the surface layer of the bearing layer with the thickness of 10-40nm, which is in contact with the diamond-like carbon film layer.

According to the invention, the effect is best when the content of the metal Cr in the surface layer of the bearing layer with the thickness of 10-40nm in contact with the metal layer is 45-60%, and the content of the metal Cr in the surface layer of the bearing layer with the thickness of 10-40nm in contact with the diamond-like carbon film layer is 15-30%.

According to the invention, the roughness Ra of the metal product can be 0.25-0.35 μm, the friction coefficient can be 0.08-0.13, and the Vickers hardness can be 1800-; preferably, the roughness Ra of the metal product is 0.25-0.33 μm, the friction coefficient is 0.08-0.11, and the Vickers hardness is 1900-; more preferably, the metal product has a roughness Ra of 0.25-0.3 μm, a friction coefficient of 0.08-0.09, and a Vickers hardness of 2000-2100hv 0.05. In the present invention, the Vickers hardness "hv 0.05" refers to the hardness measured using a force of 0.05kg, for example, the Vickers hardness of 2000-2100hv0.05 refers to the hardness measured using a force of 0.05kg of 2000-2100.

According to the invention, the metal product is subjected to a vibration friction test, and no obvious scratch or slight scratch is found, which indicates that the metal product has excellent wear resistance.

A second aspect of the invention provides a method of making a metal article, wherein the method comprises the steps of, in order:

(1) bombarding and cleaning the base material by adopting an ion source;

In the present invention, specifically, the method for preparing the metal product comprises the following steps:

(1) cleaning a substrate by ion source bombardment: placing the substrate on a clamp, vacuumizing, filling argon into a machine table, opening a rotating frame, and opening an ion source after the gas is stable;

(2) optionally depositing a metal layer by magnetron sputtering: continuously supplying argon, starting a sputtering power supply of the metal target material, and depositing a metal coating on the surface of the substrate;

(3) optional magnetron sputtering deposition of a bearing layer: introducing nitrogen and turning on a sputtering power supply of the graphite target, and depositing a bearing layer on the surface of the metal layer;

(4) magnetron sputtering deposition of a diamond-like carbon film layer: and stopping introducing nitrogen, adjusting the ambient pressure of argon, closing a sputtering power supply of the metal target material, and depositing a diamond-like carbon film layer on the surface of the bearing layer.

According to the invention, the conditions of the steps in the method comprise:

wherein, in the step (1), the degree of vacuum is 1X 10^-3To 10X 10^-3Pa, the flow rate of the argon gas is 700-800sccm, the rotating speed of the rotating frame is 10-15rpm, the ion source is 8-9kW, the temperature is 70-110 ℃, and the time is 10-20 min;

wherein, in the step (2), the flow rate of the argon gas is 700-800sccm, the magnetic control power of the metal target is 5-8kW, the sputtering pressure is 0.1-0.3Pa, and the time is 5-50 min;

wherein, in the step (3), the flow rate of the argon gas is 600-700sccm, the flow rate of the nitrogen gas is 100-200sccm, the magnetron power of the metal target is 4-8kW, the sputtering pressure of the metal target is 0.1-0.3Pa, the magnetron power of the graphite target is 5-7kW, the sputtering pressure of the graphite target is 0.1-0.3Pa, and the time is 5-50 min;

in the step (4), the flow rate of the argon gas is 700-800sccm, the magnetron power of the graphite target is 5-7kW, the sputtering pressure is 0.1-0.3Pa, and the time is 5-50 min.

In the steps (2) and (3), the flow rate of the nitrogen is injected from low to high, the sputtering pressure of the metal target is sputtered from low to high, and the sputtering pressure of the graphite target is sputtered from low to high; preferably, the flow rate of the nitrogen gas is increased by 50-100sccm within 5-15min, the sputtering pressure of the metal target is increased by 0.05-0.1Pa within 5-15min, and the sputtering pressure of the graphite target is increased by 0.05-0.1Pa within 5-15 min.

According to the present invention, it is preferred that the conditions of the steps in the method include:

wherein, in the step (1), the degree of vacuum is 1X 10^-3To 10X 10^-3Pa, the flow rate of the argon gas is 750-800sccm, the rotating speed of the rotating frame is 10-13rpm, the ion source is 8.5-9kW, the temperature is 70-110 ℃, and the time is 12-15 min;

wherein, in the step (2), the flow rate of the argon gas is 700-800sccm, the magnetic control power of the metal target is 6-8kW, the sputtering pressure is 0.1-0.2Pa, and the time is 5-50 min;

wherein, in the step (3), the flow rate of the argon gas is 600-700sccm, the flow rate of the nitrogen gas is 100-150sccm, the magnetron power of the metal target is 4-8kW, the sputtering pressure of the metal target is 0.1-0.2Pa, the magnetron power of the graphite target is 6-7kW, the sputtering pressure of the graphite target is 0.1-0.3Pa, and the time is 5-50 min;

in the step (4), the flow rate of the argon gas is 700-800sccm, the magnetron power of the graphite target is 6-7kW, the sputtering pressure is 0.1-0.2Pa, and the time is 5-50 min.

More preferably, in the steps (2) and (3), the flow rate of the nitrogen is injected from low to high, the sputtering pressure of the metal target is sputtered from low to high, and the sputtering pressure of the graphite target is sputtered from low to high; most preferably, the flow rate of the nitrogen gas is increased by 75-100sccm within 10-15min, the sputtering pressure of the metal target is increased by 0.05-0.1Pa within 10-15min, and the sputtering pressure of the graphite target is increased by 0.05-0.1Pa within 10-15 min.

In the present invention, the distribution of the Cr content in the bearing layer can be achieved by changing the sputtering power of a metal target (e.g., Cr target) and a graphite target (e.g., carbon target) and changing the content of nitrogen gas; and the prepared metal product can enhance the binding force between the diamond-like carbon film layer and the substrate, and can still improve the physical and mechanical properties of the surface of the substrate.

In the present invention, in the step (1), the ion source may be any one of an anode layer ion source, a kaffman ion source, a hall ion source, a radio frequency inductively coupled ion source, and an electron cyclotron resonance ion source.

The present invention will be described in detail below by way of examples.

In the following examples and comparative examples:

(1) roughness measurement

Roughness testing was performed according to GB/T2423 using a roughness meter purchased from hopson model TAYLOR HOBSON25, wherein the sample length: 0.80mm, the roughness of the surface of the metal article is tested.

(2) Vibration friction test

According to GB/T2423, a vibration friction test is carried out by adopting vibration friction purchased from Rosler with the model number of R180/530 TE-30;

wherein, the equipment frequency: 50 +/-0.5 HZ; device amplitude points P1 to P6, amplitude mean: 1.65. + -. 0.1mm (as shown in FIG. 5).

The vibration friction test comprises the following steps:

(a) a total of about 15L of 3 parts of RKF 10K (yellow cone) and 1 part of RKK15P (green pyramid) were prepared and charged into a grinding tank of a vibration friction device (ROSLER);

(b) pipette FC12010ml, and add water to 500ml into the grind tank;

(c) adding 0.5L of water into the grinding groove; during the test, 0.5L of water, FC12010ml, was added every 30min

(d) And (3) mounting the sample on a complete machine, and testing the sample in a vibration friction testing device for 2 hours.

(3) Photomicrograph

Is used for characterizing the surface scratching condition of the metal product. Among them, in the present invention, a microscope of type of a trinocular metallurgical microscope 54x available from Shanghai optical instruments was used.

(4) Coefficient of friction test

According to GB10006-88, a friction coefficient test is carried out by adopting a model (MXD-02) of a self-blue light machine; wherein, the load is 200g +/-20g (the weight of the original load solid, the polyurethane artificial leather below the solid and the balance paper); paper type of the balance: paramin (middle), No.: 1-4560-02.

(5) Vickers hardness test

Equipment: selecting a diamond regular rectangular pyramid pressure head by a micro Vickers hardness tester, keeping the pressure for 10s when the pressure F is 0.05kgf, and testing the metal surface;

(a) before the test, the appearance is checked to be abnormal, no color change, bubbles, cracks, falling off and the like exist, and the surface is wiped clean by using dust-free cloth;

(b) placing the sample on a Vickers hardness tester stage, adjusting the height, focusing under a 400x microscope until the surface of the sample is clearly seen, selecting a test parameter pressure F of 0.05kgf, maintaining the pressure for 10s for testing, and testing the diagonal lengths L1 and L2 of the indentation under 400x-500x times (as shown in FIG. 6);

(c) 3 positions were tested per sample and the mean values L1 and L2 calculated, substituting the formula for HV 0.1891 0.3 9.8/((L1+ L2)/2)²。

Example 1

This example illustrates an aluminum alloy rear cover of a mobile phone made by the method of the present invention.

The method comprises the following steps:

(1) cleaning a substrate by ion source bombardment: cleaning and drying a workpiece, wherein ethanol is mainly used for ultrasonic cleaning in the cleaning process, then deionized water is used for washing away residues, and the workpiece is dried in a vacuum environment; putting the workpiece on a workpiece rotating frame, vacuumizing the machine table at a pressure lower than 3 x 10^-3Pa; argon gas is filled into the machineIn the table, the flow of argon is 750sccm, the rotating frame is opened, the rotating speed of the rotating frame is 10rpm, after the gas is stable, an ion source is opened, the ion source is 8kW, the working voltage is 4.0kv, the ion beam current is 70mA, the temperature is 70 ℃, the working time is 20min, and the surface of a workpiece and the surface of a target material are subjected to ion cleaning;

(2) depositing a metal chromium layer by magnetron sputtering: continuously supplying gas by using an argon gas source, keeping the gas filling stability, starting a medium-frequency sputtering power supply of the chromium target material, using the sputtering pressure of 0.1Pa and the sputtering power of 7kW, depositing a chromium film on the surface of a workpiece by adopting medium-frequency sputtering coating, wherein the temperature is 90 ℃, the deposition time is 15min, and the thickness of the metal chromium layer is 12 nm;

(3) carrying layer carbon chromium nitride layer deposition by magnetron sputtering: then introducing nitrogen, increasing the flow of the nitrogen to 100sccm within 15min from 0sccm, adjusting the sputtering pressure by adjusting the flow of the argon, starting a graphite target sputtering power supply, increasing the sputtering voltage to 10kW from 15min from 0kW, depositing chromium carbonitride on the surface of the chromium film by using a reactive sputtering mode, wherein the film coating time is 20min, and the thickness of the chromium carbonitride layer of the bearing layer is 30 nm;

(4) magnetron sputtering deposition of a diamond-like carbon film layer: after the chromium carbonitride film is deposited for a while, closing a nitrogen source, stopping introducing nitrogen, adjusting the pressure of an argon environment, closing a chromium target sputtering power supply, only keeping a graphite target as a carbon source, and beginning to deposit a diamond-like carbon (DLC) film for 30 min; after a period of deposition, closing the graphite target, completing the deposition of the composite film, stopping introducing argon, stopping the rotation of the rotating frame, closing the gas path, sealing the working cavity, and taking out the workpiece after the temperature of the workpiece is reduced to 45 ℃; wherein the thickness of the diamond-like carbon film layer is 120 nm.

The aluminum alloy rear shell of the mobile phone is obtained and marked as S1.

The results of the performance test of this S1 are shown in table 1.

Example 2

An aluminum alloy rear cover of a cellular phone, gold of example 2, was prepared in the same manner as in example 1The thicknesses of the metal chromium layer, the bearing layer and the diamond-like carbon film layer are the same as those of the metal chromium layer, the bearing layer and the diamond-like carbon film layer in the embodiment 1, and the difference is that: controlling the conditions in the steps (2) to (4) to ensure that the Cr content A in the surface layer of the bearing layer which is in contact with the metal layer and has the thickness of 10nm is controlled₁50 percent, and the Cr content A in the surface layer of the bearing layer with the thickness of 10nm, which is in contact with the diamond-like carbon film layer₂20% of A₁Ratio A₂The height is 30 percent;

the aluminum alloy rear shell of the mobile phone is obtained and marked as S2.

The results of the performance test of this S2 are shown in table 1.

Example 3

An aluminum alloy mobile phone back case was prepared in the same manner as in example 1, except that: the thicknesses of the metal layer and the carrier layer in this example 3 are different from those in example 1;

specifically, in step (2) and step (3):

(2) depositing a metal chromium layer by magnetron sputtering: the temperature is 100 ℃, the deposition time is 30min, and the thickness of the metal chromium layer is 24 nm;

(3) carrying layer carbon chromium nitride layer deposition by magnetron sputtering: and then introducing nitrogen, increasing the flow of the nitrogen to 100sccm within 15min from 0sccm, adjusting the sputtering pressure by adjusting the flow of the argon, starting a graphite target sputtering power supply, increasing the sputtering voltage to 10kW from 15min from 0kW, depositing chromium carbonitride on the surface of the chromium film by using a reactive sputtering mode, wherein the coating time is 40min, and the thickness of the chromium carbonitride layer of the bearing layer is 60 nm.

The aluminum alloy rear shell of the mobile phone is obtained and marked as S3.

The results of the performance test of this S3 are shown in table 1.

Example 4

An aluminum alloy mobile phone back case was prepared in the same manner as in example 2, except that:

in step (2), step (3), and step (4):

(2) depositing a metal chromium layer by magnetron sputtering: the temperature is 100 ℃, the deposition time is 20min, and the thickness of the metal chromium layer is 20 nm;

(3) carrying layer carbon chromium nitride layer deposition by magnetron sputtering: then introducing nitrogen with the flow rate of 100sccm, adjusting the sputtering pressure by adjusting the flow rate of the argon, starting a graphite target sputtering power supply to sputter power by 10kW, depositing chromium carbonitride on the surface of the chromium film in a reactive sputtering mode for 30min during film coating, wherein the thickness of the chromium carbonitride layer of the bearing layer is 45 nm;

wherein the Cr content A in the surface layer of the bearing layer with the thickness of 40nm in contact with the metal layer₁45 percent of the Cr content A in the surface layer of the bearing layer with the thickness of 40nm which is in contact with the diamond-like carbon film layer₂30% of A₁Ratio A₂The height is 15 percent;

(4) magnetron sputtering deposition of a diamond-like carbon film layer: the film coating time for depositing the diamond-like carbon film (DLC) is 20 min; wherein the thickness of the diamond-like carbon film layer is 100 nm.

The aluminum alloy rear shell of the mobile phone is obtained and marked as S4.

The results of the performance test of this S4 are shown in table 1.

Example 5

An aluminum alloy mobile phone back case was prepared in the same manner as in example 2, except that: the metal target is metal titanium; the thickness of the prepared metal titanium layer is 5nm, the thickness of the bearing layer titanium carbonitride layer is 20nm, and the thickness of the diamond-like carbon film layer is 150 nm; and

the Cr content A of the surface layer of the bearing layer which is in contact with the metal layer and has the thickness of 20nm₁45 percent, and the Cr content A in the surface layer of the bearing layer with the thickness of 20nm which is in contact with the diamond-like carbon film layer₂30% of A₁Ratio A₂The height is 15 percent.

The aluminum alloy rear shell of the mobile phone is obtained and marked as S5.

The results of the performance test of this S5 are shown in table 1.

Example 6

An aluminum alloy mobile phone back case was prepared in the same manner as in example 2, except that: the Cr content A in the surface layer of the bearing layer with the thickness of 30nm in contact with the metal layer₁60 percent, and the Cr content A in the surface layer of the bearing layer with the thickness of 30nm in contact with the diamond-like carbon film layer₂15% of A₁Ratio A₂The height is 45%; and the thickness of the diamond-like carbon film layer is 100 nm.

The aluminum alloy rear shell of the mobile phone is obtained and marked as S6.

The results of the performance test of this S6 are shown in table 1.

Example 7

An aluminum alloy mobile phone back case was prepared in the same manner as in example 1, except that: the thickness of the prepared metal chromium layer is 30nm, the thickness of the bearing layer chromium carbonitride layer is 80nm, and the thickness of the diamond-like carbon film layer is 160 nm.

The aluminum alloy rear shell of the mobile phone is obtained and marked as S7.

The results of the performance test of this S7 are shown in table 1.

Example 8

An aluminum alloy mobile phone back case was prepared in the same manner as in example 1, except that: the thickness of the metal layer and the carrier layer was different from the thickness of the metal layer and the carrier layer as defined in example 1, i.e. the thickness of the metal layer was 15nm, the thickness of the carrier layer was 15nm, and the thickness of the diamond-like thin film layer was 80 nm.

The aluminum alloy rear shell of the mobile phone is obtained and marked as S8.

The results of the performance test of this S8 are shown in table 1.

Example 9

Following the same procedure as in example 2The method prepares the aluminum alloy mobile phone back shell, and is different from the following steps: the Cr content A in the surface layer of the bearing layer with the thickness of 10nm in contact with the metal layer₁40 percent, and the Cr content A in the surface layer of the bearing layer with the thickness of 10nm, which is in contact with the diamond-like carbon film layer₂40% of A₁And A₂The same is true.

The aluminum alloy rear shell of the mobile phone is obtained and is marked as DS 3.

The results of the performance test of this S9 are shown in table 1.

Comparative example 1

An aluminum alloy mobile phone back case was prepared in the same manner as in example 1, except that: step (3) was not performed, i.e., no carrier layer (chromium carbonitride layer) was deposited.

The aluminum alloy rear shell of the mobile phone is obtained and is marked as DS 1.

The DS1 was subjected to performance testing, and the results are shown in Table 1.

Comparative example 2

An aluminum alloy mobile phone back case was prepared in the same manner as in example 1, except that: step (2) was not performed, i.e., no metal layer (chrome layer) was deposited.

The aluminum alloy rear shell of the mobile phone is obtained and is marked as DS 2.

The DS2 was subjected to performance testing, and the results are shown in Table 1.

Comparative example 3

An aluminum alloy mobile phone back case was prepared in the same manner as in example 1, except that: replacing the diamond-like thin film layer with a diamond-like thin film layer doped with Cr and Ti.

The DS3 was subjected to performance testing, and the results are shown in Table 1.

Comparative example 4

An aluminum alloy mobile phone back case was prepared in the same manner as in example 1, except that: plating a bearing layer on the substrate, plating a metal layer on the bearing layer, and plating a diamond-like thin film layer on the metal layer.

The aluminum alloy rear shell of the mobile phone is obtained and is marked as DS 4.

The DS4 was subjected to performance testing, and the results are shown in Table 1.

Comparative example 5

An aluminum alloy mobile phone back case was prepared in the same manner as in example 1, except that: the comparative example was not plated with the metal layer and the carrier layer;

specifically, step (4) is directly performed after step (1) without performing steps (2) and (3):

(1) cleaning a substrate by ion source bombardment: cleaning and drying a workpiece, wherein ethanol is mainly used for ultrasonic cleaning in the cleaning process, then deionized water is used for washing away residues, and the workpiece is dried in a vacuum environment; placing the workpiece on a workpiece rotating frame, vacuumizing the machine table, wherein the pressure is lower than 3 x 10^-4Pa; argon is filled into a machine table, the flow of the argon is 700sccm, a rotating frame is opened, the rotating speed of the rotating frame is 10rpm, after the gas is stable, an ion source is opened, the ion source is 9KW, the working voltage is 4.0kv, the ion beam current is 70mA, the temperature is 100 ℃, the working time is 20min, and the surface of a workpiece and the surface of a target material are subjected to ion cleaning;

(4) magnetron sputtering deposition of a diamond-like carbon film layer: adjusting the pressure of an argon environment, closing a chromium target sputtering power supply, only keeping a graphite target as a carbon source, controlling the magnetic control power of the graphite target to be 7KW, and beginning to deposit a diamond-like carbon (DLC) film for 30 min; after a period of deposition, closing the graphite target, completing the deposition of the composite film, stopping introducing argon, stopping the rotation of the rotating frame, closing the gas path, sealing the working cavity, and taking out the workpiece after the temperature of the workpiece is reduced to 45 ℃; wherein the thickness of the diamond-like carbon film layer is 160 nm.

The aluminum alloy rear shell of the mobile phone is obtained and is marked as DS 5.

The DS5 was subjected to performance testing, and the results are shown in Table 1.

TABLE 1

	Roughness (μm)	Vibration friction	Coefficient of friction	Vickers hardness (hv0.05)
					Example 1	0.33	Has slight scratch	0.13	1950
Example 2	0.33	No obvious scratch	0.12	2000
					Example 3	0.35	Has slight scratch	0.13	1930
Example 4	0.35	Has slight scratch	0.10	1850
					Example 5	0.25	Has slight scratch	0.11	1830
Example 6	0.3	No obvious scratch	0.09	2100
					Example 7	0.35	Has slight scratch	0.13	1900
Example 8	0.35	Has slight scratch	0.13	1820
					Example 9	0.35	Has slight scratch	0.13	1800
Comparative example 1	0.45	Obvious scratch	0.16	1550
					Comparative example 2	0.45	Obvious scratch	0.16	1500
Comparative example 3	0.40	Obvious scratch	0.15	1650
					Comparative example 4	0.41	Obvious scratch	0.15	1700
Comparative example 5	0.45	Obvious scratch	0.14	1700

From the data of examples 1-9 and comparative examples 1-5 it can be seen that: the metal product of the invention can enhance the binding force of the diamond-like carbon film layer and the substrate and can still improve the physical and mechanical properties of the surface of the substrate. And micrographs of metallic articles prepared according to fig. 1, 2, 3 and 4, example 6, example 2, example 3 and example 4 of the present invention, wherein example 2 and example 6 were not visibly scratched and example 3 and example 4 were slightly scratched. In addition, the metal product prepared by the invention has low roughness and friction coefficient values, and the Vickers hardness value is higher than that of the comparative example.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. The metal product is characterized by consisting of a substrate, and a metal layer, a bearing layer and a diamond-like carbon film layer which are sequentially deposited on the surface of the substrate;

2. The metal article of claim 1, wherein the substrate is an aluminum alloy; the metal layer is a Cr layer; the bearing layer is a CrCN layer.

3. The metal product as claimed in claim 1, wherein the metal layer has a thickness of 5-30nm, the carrier layer has a thickness of 20-80nm, and the diamond-like thin film layer has a thickness of 100-160 nm; preferably, the thickness of the metal layer is 12-24nm, the thickness of the bearing layer is 30-60nm, and the thickness of the diamond-like thin film layer is 120-150 nm.

4. The metal article according to any one of claims 1 to 3, wherein the metallic Cr content of the surface layer of the carrier layer in contact with the metal layer is A₁The content of metal Cr in the surface layer of the bearing layer in contact with the diamond-like carbon film layer is A₂Said A is₁Than the A₂15-45% higher, preferably, said A₁The content of metal Cr in the surface layer of the bearing layer with the thickness of 10-40nm, which is in contact with the metal layer, is shown in the specification₂The metal in the surface layer of the bearing layer with the thickness of 10-40nm is contacted with the diamond-like carbon film layerThe content of Cr.

5. The metal product of claim 4, wherein the metal Cr content in the surface layer of the carrier layer having a thickness of 10-40nm in contact with the metal layer is 45-60%, and the metal Cr content in the surface layer of the carrier layer having a thickness of 10-40nm in contact with the diamond-like thin film layer is 15-30%.

6. The metal article as claimed in claim 1, wherein the metal article has a roughness Ra of 0.25-0.35 μm, a friction coefficient of 0.08-0.13, and a vickers hardness of 1800-.

7. The metal article as claimed in claim 6, wherein the metal article has a roughness Ra of 0.25-0.33 μm, a friction coefficient of 0.08-0.11, and a Vickers hardness of 1900-.

8. A method for producing a metal product according to any one of claims 1 to 7, characterized in that it comprises the following steps in sequence:

(1) bombarding and cleaning the base material by adopting an ion source;

9. The method according to claim 7, wherein in steps (2) and (3), the flow rate of the used nitrogen is injected from low to high, the sputtering pressure of the used metal target is sputtered from low to high, and the sputtering pressure of the used graphite target is sputtered from low to high; preferably, the flow rate of the nitrogen gas is increased by 50-100sccm within 5-15min, the sputtering pressure of the metal target is increased by 0.05-0.1Pa within 5-15min, and the sputtering pressure of the graphite target is increased by 0.05-0.1Pa within 5-15 min.

10. A mobile phone back case, characterized in that, the mobile phone back case is made of the metal product of any one of claims 1-7 or the metal product made by the preparation method of claim 8 or 9.