CN109898064B - DLC/Me-C composite film and preparation method thereof - Google Patents

Abstract

A DLC/Me-C composite thin film and a preparation method thereof. The composite thin film is prepared by using magnetron sputtering technology on the surface of a metal or alloy substrate to sequentially prepare a Me-C thin film and a DLC thin film. The preparation method is that a metal or alloy substrate is placed in a magnetron sputtering device, and Me-C thin films and DLC thin films are prepared in situ on the surface of the metal or alloy substrate. The invention adopts radio frequency bias to assist magnetron sputtering to deposit DLC, and efficiently prepares a diamond-like film with high bonding strength of film base and excellent mechanical properties, friction resistance and corrosion resistance. In the present invention, the Me-C transition layer is selected as the buffer layer, which solves the problem of excessive stress in the DLC film; at the same time, before the Me-C buffer layer is prepared, the substrate is bombarded with plasma to prepare the amorphous modified layer, and the surface state of the substrate is improved. , reducing the corrosion potential between the matrix and the second phase, and the results confirm that the amorphous layer/Me‑C/DLC film has excellent mechanical properties and corrosion resistance.

Description

A kind of DLC/Me-C composite film and preparation method thereof

technical field

The invention discloses a DLC/Me-C composite film and a preparation method thereof, belonging to the technical field of diamond-like film material preparation.

Background technique

Diamond-like carbon films have excellent mechanical, friction resistance, corrosion resistance, and can be deposited at low temperature, and have great application potential in tribology, biomedical and other fields. However, the diamond-like carbon film has a characteristic - high internal stress, which makes the bonding force of the film base very weak and its own thickness is very limited. A transition layer or doping must be added for such diamond films. Doping, on the other hand, may weaken the performance of a certain aspect of the diamond-like carbon film. Therefore, finding a suitable transition layer is the key to promoting the application of diamond-like carbon films. The transition layer not only affects the bonding force of the diamond-like carbon film, but also has a great influence on the corrosion resistance. Therefore, in addition to the high bonding strength with the matrix and the diamond-like carbon film, it also has a high corrosion resistance and does not accelerate the corrosion of the film or substrate.

At present, there are three main preparation methods for diamond-like carbon films: cathodic arc deposition, plasma enhanced CVD (PECVD) and magnetron sputtering.

Cathodic arc is one of the earliest methods used to deposit diamond-like carbon films. It is to deposit carbon atoms on the substrate under the action of a strong electric field. The main defects are: 1. The prepared diamond-like carbon films have extremely high internal The stress limits the thickness of the diamond-like carbon film to the nanometer level, and it is difficult to add a transition layer or doping; 2. The strong electric field causes a large number of graphite particles to be bombarded and finally deposited on the substrate, so high-quality diamond-like carbon film cannot be obtained. Adding a magnetic filter device to reduce graphite particles will filter a large part of carbon ions or atoms at the same time and reduce the deposition efficiency, and the filter device is complicated and costly. Although magnetic filtration cathodic arc can prepare diamond-like carbon films with high sp3C content, it cannot be applied industrially and is not favored by enterprises.

The deposition efficiency of the diamond-like carbon film prepared by PECVD is high, and the sp3C content of the diamond-like carbon film is relatively low, and the internal stress is relatively low, and the comprehensive performance is excellent. However, its doping elements must be input in the form of atmosphere, which greatly hinders the preparation of metal-doped films diamond film.

Magnetron sputtering mainly includes ion source assisted magnetron sputtering and DC bias magnetron sputtering; ion source assisted magnetron sputtering can prepare diamond-like carbon films with high bonding strength and many types, but the overall performance is slightly worse. Source and maintenance costs are high. When DC bias magnetron sputtering is used to prepare diamond-like carbon films, the metal target is insulated due to the formation and accumulation of carbides on the target surface during sputtering, and the positive ions bombarding the target surface will accumulate on the target surface, resulting in the potential of the target. The electric field between the electrodes gradually decreases until the glow discharge is extinguished and the sputtering stops. At the same time, due to the poor conductivity of the DLC film itself, the DC bias effect will weaken or even no longer work, resulting in limited film deposition thickness. . In the three different preparation methods, the substrate bias is essential, but since the conductivity of the diamond-like carbon film is extremely low, and the prior art usually uses a DC bias, the substrate bias increases with the increase of the deposition thickness. The effect on the structure of the diamond-like carbon film is weakened, and it fails completely when the thickness reaches 4 μm.

In addition, due to the defects of the DLC film, the electrolyte diffuses to the substrate along the defects, resulting in corrosion of the microbattery, and the corrosion rate is very fast even exceeding the substrate without film protection, resulting in poor long-term corrosion resistance of the substrate protected by the DLC film. Although the prior art adopts the structure of the transition layer, it does not solve the potential problem between the film layer, the transition layer and the substrate, and its corrosion resistance performance is not satisfactory.

To sum up, the existing technology has the defects of unsatisfactory film-base bonding force, large internal stress of the film layer, unsatisfactory corrosion resistance, and high preparation cost. Therefore, it is urgent to provide an effective solution.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a low-cost and high-efficiency method for preparing a diamond-like carbon film with excellent comprehensive properties.

The present invention is a DLC/Me-C composite film, which is to prepare Me-C film and DLC film sequentially on the surface of a metal or alloy substrate by using magnetron sputtering technology.

The invention is a DLC/Me-C composite film. After the amorphous metal or alloy modified layer is prepared on the surface of the metal or alloy substrate, the Me-C film and the DLC film are sequentially prepared by the magnetron sputtering technology; Or the thickness of the alloy modified layer is 5-100 nm.

The present invention is a DLC/Me-C composite film, wherein the metal or alloy matrix is selected from the group consisting of metal magnesium, aluminum, titanium, copper, iron and alloys thereof.

The present invention is a DLC/Me-C composite film, wherein the Me-C film has a gradient structure, the Me content in the Me-C film decreases sequentially, while the C content increases sequentially, and the Me in the Me-C film is selected Self-formable strong carbide element; specifically selected from one of Cr, Ti, Si, W, Mo.

A method for preparing a DLC/Me-C composite thin film of the present invention is to place a metal or alloy substrate in a magnetron sputtering device, and in-situ prepare a Me-C thin film and a DLC thin film on the surface of the metal or alloy substrate.

The present invention provides a method for preparing a DLC/Me-C composite thin film. The Me-C thin film is prepared by reactive magnetron sputtering, Me is used as a sputtering target, and the sputtering atmosphere is Ar, C ₂ H ₂ , and CH ₄ . At least one mixed atmosphere, the sputtering source is selected from one of radio frequency, intermediate frequency or DC power supply, during the preparation process, the content of Me is controlled to decrease linearly, and the flow rate of the carbon-containing atmosphere increases linearly to prepare a gradient Me-C thin film; The rate of linear decrease of the content of carbon-containing atmosphere is the same as the rate of linear increase of the flow rate of carbon-containing atmosphere;

The magnetron sputtering process parameters are:

In the mixed atmosphere, the flow ratio of Ar to C ₂ H ₂ or Ar to CH ₄ is 1-8, the target power density is 3.5-18.5W·cm ^-2 , the working pressure is 0.5-10Pa, and the deposition time is 5-60min.

During the preparation process, the content of Me gradually decreased to 0, and the content of carbon-containing atmosphere gradually increased from 0 to 100%;

When the DLC film is prepared, a graphite target or metal is used as the sputtering target. When graphite is used as the target, the sputtering atmosphere is argon, and the sputtering source is radio frequency, intermediate frequency or DC power supply; the magnetron sputtering process parameters are:

The target power density is 3.5-18.5W·cm ^-2 , the working pressure is 0.25-5Pa, the deposition time is 5-60min, and the bias voltage is 20V-300V.

When a metal target is used for sputtering, the sputtering atmosphere is a mixed atmosphere of Ar and C ₂ H ₂ or Ar and CH ₄ , and the sputtering source is a radio frequency or intermediate frequency power supply; the metal target is selected from W, Mo, Ti, Cr, Si, One of Al or its alloy; the magnetron sputtering process parameters are:

In the mixed atmosphere, the flow ratio of Ar and C ₂ H ₂ or Ar and CH ₄ is 0.5-6, the target power density is 3.5-18.5W·cm ^-2 , the working pressure is 0.5-10Pa, the deposition time is 5-60min, and the bias is applied. Voltage 20V-300V.

The invention provides a method for preparing a DLC/Me-C composite film. When preparing the DLC film, the initial bias voltage is 20-25V. During the magnetron sputtering process, the bias voltage is increased every 5-10 minutes, and the bias voltage is adjusted The increase rate is 5-30V. When the bias voltage reaches 300V, the bias voltage adjustment is stopped, so that the film has a gradient hardness that is continuously enhanced from the inside to the outside, reduces the residual stress in the film, and improves the wear resistance of the film.

The present invention is a preparation method of a DLC/Me-C composite film. A metal or alloy substrate is placed on a sample base of a magnetron sputtering equipment, and the sample base is insulated from a grounded vacuum chamber and connected to a polarizing power supply. While the metal or alloy substrate is biased, the surface of the metal or alloy substrate is bombarded with plasma, ion etching and ion implantation are performed on the surface of the metal or alloy substrate, and after the surface modification layer is obtained, magnetron sputtering is used on the metal or alloy substrate. Me-C thin films and DLC thin films were prepared on the surface modified layer.

A preparation method of a DLC/Me-C composite film of the present invention, and the parameters of the plasma bombardment treatment process are:

A bias voltage of 500-1000V is applied, Ar plasma or Ar and N plasma, and the duration is 10-60min; the thickness of the surface modification layer is 5-100nm, and the surface modification layer is an amorphous layer.

According to various defects of the prior art, the present invention proposes a radio frequency bias-assisted magnetron sputtering deposition of DLC, which can apply radio frequency bias voltages of different sizes to the substrate, and can efficiently prepare a film substrate with high bonding strength, mechanical properties and friction resistance. Diamond-like carbon film with excellent performance and corrosion resistance. By changing the RF bias, the ratio between sp2 and sp3 in the diamond-like carbon film can be changed, and the structure of the diamond-like carbon film can be effectively controlled in a wide range. Because of the present invention, the DLC can be doped or the transition layer can be prepared by using a gas doping source or a metal target. In the present invention, the Me-C transition layer is selected as the buffer layer between the DLC film and the substrate, which solves the problem of excessive stress in the DLC film and further improves the performance of the DLC. At the same time, before preparing the Me-C transition layer, we use Under the condition of high radio frequency bias, the substrate was bombarded with Ar and N plasma, and an amorphous modified layer was prepared on the substrate. Combining the advantages of performance and reducing the corrosion potential between the matrix and the second phase, the results confirm that the amorphous layer/Me-C/DLC film has excellent mechanical properties and corrosion resistance.

The present invention has the following advantages due to the adoption of the above-mentioned process method and film structure:

1. The use of radio frequency bias-assisted magnetron sputtering preparation technology has the advantages of low-cost and high-efficiency preparation of diamond-like carbon films with excellent comprehensive properties. This technology can not only use RF bias to ion clean the substrate to improve the bonding force, but also use RF bias to improve the ionization rate of the carbon-containing atmosphere while applying substrate bias to improve the mechanical properties, and the magnetron target can not only Deposition of transition layers can also provide doping elements, or use graphite targets to prepare intrinsic diamond-like carbon films.

An additional advantage of RF substrate biasing is that there is no significant reduction in biasing effect with increasing film thickness. Because the radio frequency power supply is alternating current, the cycle acts on the target alternately, when the sputtering target is in the positive half cycle, the electrons flow to the target surface, neutralize the positive charge accumulated on the surface, and accumulate electrons, making the surface present a negative bias. The negative half cycle of the RF voltage attracts positive ions to bombard the target, so that the sputtering process can continue, reducing or preventing the occurrence of target poisoning; in addition, the RF voltage can pass through any kind of impedance, so when the DLC film is deposited thicker When the DLC film itself has a weak shielding effect on the RF power supply, the bias voltage can continue to be applied without being affected by the thickness.

2. Prepare an amorphous transition layer to effectively improve the bonding force of the film base

1) The amorphous modified layer improves the surface state of the substrate and makes the surface denser;

Due to the uniform single phase of the amorphous layer, the composition and structure are more uniform, the composition fluctuates less, there is no obvious grain boundary, no second phase particles or dislocations, etc., so the preparation of the amorphous modified layer on the surface of the substrate can greatly improve the Improve the unevenness of the surface of the base metal or alloy, and eliminate existing defects such as holes or pores, cracks, and pinholes on the base surface, thereby greatly reducing the number of core corrosion defects on the base surface and improving the corrosion resistance of the composite film structure. .

2) The amorphous modified layer reduces the corrosion potential between the matrix and the second phase;

The ion bombardment or etching during the preparation of the amorphous layer can chemically combine the matrix or its impurity elements with the same ions to generate a new phase with similar structure, which increases the chemical uniformity of the surface of the matrix and reduces the original matrix. and the corrosion potential between the second phase. In addition, the amorphous layer can inhibit the diffusion of impurity elements in the matrix to the surface of the matrix, and avoid the situation that the impurities diffuse to the surface of the matrix and become the pitting core.

3) During the preparation of the amorphous modified layer, a new corrosion-resistant phase is produced in the matrix:

During the process of ion bombardment or ion implantation, a new phase will be formed by combining with the matrix atoms. For example, N plasma bombardment or N ion implantation on the surface of the magnesium alloy substrate will generate a new phase of Mg3N2, which is a corrosion-resistant phase, which is a corrosion-resistant phase, thereby improving the corrosion resistance of the substrate surface.

4) Due to the disorder of the structural atoms of the amorphous layer itself, the amorphous layer itself has good corrosion resistance, and at the same time, it is very difficult for impurity ions or ions in the electrolyte to move in the amorphous layer, thus hindering the The occurrence of substrate corrosion.

The present invention uses plasma to bombard the metal or alloy surface. Because of the use of a bias voltage of several hundred volts or even thousands of volts, the plasma bombardment is completed under the condition of a relatively large bias voltage, which causes the surface temperature of the substrate to rise rapidly, and the surface composition of the substrate is different from that of the substrate. The plasma composition will undergo a certain metallurgical bond at a higher temperature, or the composition of the surface layer of the matrix will be re-dissolved. After the plasma bombardment ends, the bias voltage is suddenly reduced to a very low value or the transition layer is directly turned off to start the deposition of the transition layer. The whole process on the surface of the substrate only lasts about 10-20 minutes, so the temperature of the surrounding environment will not increase significantly when the substrate rapidly rises to high temperature. In the surrounding environment, it cools rapidly, so the plasma bombardment is approximately a process of rapid melting and solidification, which satisfies the rapid cooling conditions required for the formation of an amorphous layer. In addition, when plasma bombards the surface of the substrate under the action of a high bias voltage, high-energy particles strike the surface of the substrate to generate a large number of vacancies or interstitial atoms. These point defects will continuously migrate and form dislocations under the action of thermal activation. Under high-energy bombardment for a longer time, higher dislocation density will be caused. Due to the inherent limit of the dislocation density that can be maintained on the surface of each metal or alloy, when the dislocation density caused by plasma bombardment on the surface of the substrate exceeds When this inherent limit is reached, the internal lattice collapse on the surface of the matrix will cause a disordered state and eventually an amorphous layer will be formed on the surface of the matrix.

3. Through the amorphous transition layer, the film base potential can be effectively improved

The present invention uses the plasma immersion ion implantation technology as the pretreatment method for depositing thin films, which is very suitable for implanting N ions because of its low energy requirement, high efficiency, and easy realization of compounding with other vacuum preparation technologies. In addition to changing the composition, the corrosion resistance can also be improved by changing the structure of the metal or alloy; so that the metal or alloy has long-term stable corrosion resistance.

4. The present invention adopts in-situ continuous preparation of Me-C/DLC film. There is no obvious boundary between the Me-C film layer and the DLC. The film layers are combined very closely, and there are basically no defects or holes, which effectively blocks the penetration of the electrolyte. In addition, in the Me-C/DLC film, Me and C change in a gradient, that is, the content of C element gradually increases from the Me-C layer to the DLC film, while the content of metal element Me Gradually reduce to 0; especially the DLC film is prepared under changing bias voltage, and the structure of the DLC film changes continuously, which is manifested in the gradual increase of the sp3 ratio in the DLC film, which effectively reduces the residual stress of the film and improves the film. quality and performance.

To sum up, the radio frequency bias-assisted magnetron sputtering technology of the present invention solves various defects existing in the prior art, and has obvious advantages.

Description of drawings

1 is a cross-sectional view of the film prepared in Example 3 of the present invention;

FIG. 2 is an element line energy spectrum distribution diagram corresponding to the position of the horizontal white line in FIG. 1 .

It can be seen from FIG. 1 that the gradient composition DLC:H prepared by the present invention has a thickness of about 4 μm, and there is no new interface between the prepared thin film layers.

It can be seen from the element distribution diagram in FIG. 2 that the C content of the film prepared by the present invention gradually increases from 0 to 100%, while the Cr content gradually decreases to 0, and almost all of the outermost layer is C in the range of 1 μm.

Detailed ways

Below in conjunction with embodiment and comparative example, the present invention is described in further detail.

Example 1: Preparation of DLC/Me-C composite film with amorphous layer (ex-situ deposition)

(1) Preparation of Ar, N plasma modified layer

Using stainless steel as the substrate, put the cleaned stainless steel substrate into the sputtering chamber, the substrate is facing the graphite target, the substrate is connected to a radio frequency power supply, and argon and nitrogen gas are introduced, the flow ratio is 4:1, the sputtering power supply is a DC power supply, and the power supply The power was 37W, the working pressure was 1.1pa, the substrate bias was 700V, and the bombardment time was 15min, and an amorphous modified layer was obtained on the surface of the substrate.

(2) Preparation of gradient Cr-doped CrC transition layer

Make the stainless steel substrate face the metal chromium target, connect the RF power supply to the substrate, and feed argon and acetylene at the same time. During the deposition process, the argon flow rate is fixed at 16sccm, and the acetylene flow rate is slowly increased from 0 (sccm) to 6 (sccm), the bias voltage Gradually increase from 40V to 110V. The sputtering power supply is a DC power supply, the power supply power is 200W, the working pressure is 0.8pa, and the deposition time is 15min; due to the use of a DC sputtering source, the carbides generated and accumulated on the surface of the target during sputtering will cause the metal target to be insulated. With the extension of time, the number of chromium ions in the metal chromium target will gradually decrease to zero, and the gradient distribution of Cr and C in the film layer will be realized.

(3) Preparation of DLC film

The substrate is facing the graphite target, the substrate is connected to a radio frequency power supply, a bias voltage of 130V is applied, and argon and acetylene are fed at the same time. The flow ratio is 8:3. .

Example 2: Preparation of DLC/Me-C composite film by in-situ deposition (without amorphous layer)

(1) In-situ deposition of a DLC film containing a transition layer with gradient bias and composition so that the stainless steel substrate faces the metal chromium target, the substrate is connected to a radio frequency power supply, and argon and acetylene are fed at the same time. During the deposition process, the argon gas flow is fixed at 16sccm , the acetylene flow increased from 0 (sccm) every 2 minutes by 1 sccm to 8 (sccm), while linearly increasing the substrate bias, increasing from 25V per minute to 5V to 140V. The sputtering power source is a DC power source, the power source is 150W, the working pressure is 0.75Pa, and the deposition time is 30min.

Example 3: Preparation of DLC/Me-C composite film by in-situ deposition of amorphous layer

(1) Preparation of Ar, N plasma modified layer

Using stainless steel as the substrate, put the cleaned stainless steel substrate into the sputtering chamber, the substrate is facing the graphite target, the substrate is connected to a radio frequency power supply, and argon and nitrogen gas are introduced, the flow ratio is 4:1, the sputtering power supply is a DC power supply, and the power supply The power was 37W, the working pressure was 1.1pa, the substrate bias was 700V, and the bombardment time was 15min, and an amorphous modified layer was obtained on the surface of the substrate.

(2) In-situ deposition of gradient bias and composition of DLC films containing transition layers

The stainless steel substrate is facing the metal chromium target, the substrate is connected to the RF power supply, and argon gas and acetylene gas are fed at the same time. During the deposition process, the argon gas flow rate is fixed at 16sccm, and the acetylene flow rate increases from 0 (sccm) every 2 minutes to 1sccm until it increases to 8 ( sccm), while linearly increasing the substrate bias, increasing 5V per minute from 25V to 140V. The sputtering power supply is a DC power supply, the power supply power is 150W, the working pressure is 0.75Pa, and the deposition time is 30min; due to the use of a DC sputtering source, the carbides generated and accumulated on the surface of the target during sputtering will cause the metal target to be insulated. With the extension of time, the number of chromium ions in the metal chromium target will gradually decrease to zero, and the gradient distribution of Cr and C in the film layer will be realized.

Example 4:

DLC/Me-C composite films prepared by Me-C gradient adjustment using RF sputtering source

(1) Preparation of Ar, N plasma modified layer

Using stainless steel as the substrate, put the cleaned stainless steel substrate into the sputtering chamber, the substrate is facing the graphite target, the substrate is connected to a radio frequency power supply, and argon and nitrogen gas are introduced, the flow ratio is 4:1, the sputtering power supply is a DC power supply, and the power supply The power was 37W, the working pressure was 1.1pa, the substrate bias was 700V, and the bombardment time was 15min, and an amorphous modified layer was obtained on the surface of the substrate.

(2) In-situ deposition of gradient bias and composition of DLC films containing transition layers

The stainless steel substrate is facing the metal chromium target, the substrate is connected to the RF power supply, and argon gas and acetylene gas are fed at the same time. During the deposition process, the argon gas flow rate is fixed at 16sccm, and the acetylene flow rate increases from 0 (sccm) every 2 minutes to 1sccm until it increases to 8 ( sccm), while linearly increasing the substrate bias, increasing 5V per minute from 25V to 140V. The sputtering power source is a radio frequency source, the power supply is 150W, and the radio frequency power is adjusted by 20W every 2 minutes until the radio frequency power is zero, and the gradient distribution of Cr and C in the film layer is realized, the working pressure is 0.75Pa, and the deposition time is 30min;

Comparative Example 1: DLC/Me-C composite film without amorphous layer and ex-situ deposition

(1) Preparation of gradient Cr-doped CrC transition layer

Make the stainless steel substrate face the metal chromium target, connect the RF power supply to the substrate, and feed argon and acetylene at the same time. During the deposition process, the argon flow rate is fixed at 16sccm, and the acetylene flow rate is slowly increased from 0 (sccm) to 6 (sccm), the bias voltage Gradually increase from 40V to 110V. The sputtering power source is a DC power source, the power source is 200W, the working pressure is 0.8pa, and the deposition time is 15min.

(2) Preparation of DLC film

The substrate is facing the graphite target, the substrate is connected to a radio frequency power supply, a bias voltage of 130V is applied, and argon and acetylene are fed at the same time. The flow ratio is 8:3. .

Comparative Example 2: DLC/Me-C film without gradient composition change

(1) Preparation of CrC transition layer

The substrate is facing the chromium target, the substrate is connected to a radio frequency power supply, a bias voltage of 50V is applied, and argon and acetylene are fed at the same time, the flow ratio is 16:3, the sputtering power supply is a DC power supply, the power supply power is 200W, the working pressure is 0.8pa, and the deposition time is 15min .

(2) Preparation of DLC film

The substrate is facing the graphite target, the substrate is connected to a radio frequency power supply, a bias voltage of 130V is applied, and argon and acetylene are fed at the same time. The flow ratio is 8:3. .

Performance test results:

The properties of the obtained diamond-like composite films were tested, and the results are shown in Table 1. The nanoindentation technique was used to measure the nanohardness of the film, and the constant load mode was used to test the nanohardness so that the indentation depth did not exceed one tenth of the overall thickness of the film. The wear resistance was characterized by a friction and wear test, using a silicon nitride ball (diameter 4.2 mm) as a counterpart, a sliding distance of 8 mm, a load of 8 N, and a frequency of 8 Hz. Passed the electrochemical test (test conditions: three-electrode system, the reference electrode was a saturated Ag/AgCl electrode, the counter electrode was a Pt sheet (15mm×15mm×0.1mm), the sample was a working electrode (exposed area 0.25cm ² ), and the electrolyte was 3.5 wt.%NaCl solution) to understand its corrosion resistance, and obtain its corrosion current through the Tafel polarization curve.

Table 1

Comprehensive performance comparison:

Nanohardness:

Example 3>Example 4>Example 2>Example 1>Comparative Example 2>Comparative Example 1

Friction coefficient:

Example 4=Example 3<Example 2<Example 1<Comparative example 1<Comparative example 2;

Corrosion current density:

Example 3<Example 4<Example 2<Example 1<Comparative Example 1<Comparative Example 2.

Claims (7)

1. A DLC/Me-C composite film is characterized in that after an amorphous metal or alloy modified layer is prepared on the surface of a metal or alloy substrate, a magnetron sputtering technology is adopted to prepare a Me-C film and a DLC film in sequence.

2. The DLC/Me-C composite film according to claim 1, wherein the amorphous metal or alloy-modified layer has a thickness of 5 to 100 nm.

3. DLC/Me-C composite film according to claim 2, characterized in that the metal or alloy matrix is selected from the group consisting of metallic magnesium, aluminium, titanium, copper, iron and alloys thereof.

4. The DLC/Me-C composite film according to claim 3, wherein said Me-C film has a gradient structure, the content of Me in said Me-C film decreases in sequence, the content of C in said Me-C film increases in sequence, and Me in said Me-C film is selected from the group consisting of elements capable of forming strong carbides; specifically, the metal is one selected from Cr, Ti, Si, W and Mo.

5. A method of producing a DLC/Me-C composite film according to claim 1, characterized in that:

placing a metal or alloy matrix on a sample base station of a magnetron sputtering device, insulating the sample base station and a grounded vacuum chamber and connecting a jet bias power supply, applying bias voltage to a pure metal or alloy matrix, bombarding the surface of the metal or alloy matrix by adopting plasma, performing ion etching and ion implantation on the surface of the metal or alloy matrix to obtain a surface modification layer, and preparing a Me-C film and a DLC film on the surface modification layer of the metal or alloy matrix by adopting magnetron sputtering;

the Me-C film is prepared by adopting reactive magnetron sputtering, Me is taken as a sputtering target material, and the sputtering atmosphere is Ar and C₂H₂Ar and CH₄The sputtering source is selected from one of radio frequency, intermediate frequency or direct current power supply, during the preparation process, the content of Me is controlled to be linearly reduced, the flow of the carbon-containing atmosphere is linearly increased, and the gradient Me-C film is prepared; the magnetron sputtering process parameters are as follows:

ar and C in mixed atmosphere₂H₂Or Ar and CH₄The flow ratio of (A) is 1-8, and the target power density is 3.5-18.5 W.cm^-2The working pressure is 0.5-10Pa, and the deposition time is 5-60 min;

in the preparation process, the content of Me is gradually reduced to 0, and the content of carbon-containing atmosphere is gradually increased to 100 percent from 0;

when the DLC film is prepared, a graphite target or metal is used as a sputtering target material, when the graphite is used as the target material, the sputtering atmosphere is argon, and a sputtering source is a radio frequency, intermediate frequency or direct current power supply; the magnetron sputtering process parameters are as follows:

the target power density is 3.5-18.5 W.cm^-2The working pressure is 0.25-5Pa, the deposition time is 5-60min, and the bias voltage is applied to 20V-300V;

when the metal target is adopted for sputtering, the sputtering atmosphere is Ar and C₂H₂Or Ar and CH₄The sputtering source is a radio frequency or medium frequency power supply; the metal target is selected from one of W, Mo, Ti, Cr, Si and Al or alloy thereof; the magnetron sputtering process parameters are as follows:

ar and C in mixed atmosphere₂H₂Or Ar and CH₄The flow ratio of (A) is 0.5-6, and the target power density is 3.5-18.5 W.cm^-2The working pressure is 0.5-10Pa, the deposition time is 5-60min, and the bias voltage is 20V-300V.

6. The method for preparing DLC/Me-C composite film according to claim 5, wherein: when preparing the DLC film, the initial bias voltage is 20-25V, the bias voltage is adjusted and increased once every 5-10 minutes in the magnetron sputtering process, the amplitude of the bias voltage is 5-30V, and when the bias voltage reaches 300V, the bias voltage is stopped to be adjusted and increased.

7. The method for preparing DLC/Me-C composite film according to claim 6, wherein: the plasma bombardment treatment process parameters are as follows:

applying a bias voltage of 500-1000V, Ar plasma or Ar and N plasma for 10-60 min; the thickness of the surface modification layer is 5-100 nm, and the surface modification layer is an amorphous layer.

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