Lubricating DLC (Diamond Like Carbon) film, preparation method thereof, sliding vane and compressor

Abstract

The invention relates to the technical field of surface treatment, and discloses a lubricating DLC film, a preparation method thereof, a sliding vane and a compressor. The lubricating DLC thin film comprises a Cr layer on the bottom layer, a Cr-C transition layer on the middle layer and a DLC film layer on the surface layer. The Cr content in the Cr-C transition layer is gradually reduced along the direction from the bottom layer to the surface layer, and the C content is gradually increased along the direction from the bottom layer to the surface layer. The pure Cr layer in the lubricating DLC thin film can effectively prevent elements of the sliding sheet substrate from diffusing into the DLC thin film, and the purity and performance of the DLC thin film can be maintained. On the basis, the content gradient change of the two elements of Cr and C forms a transition middle layer, and depending on the chemical affinity characteristic of Cr and C, the binding force of the DLC film and the sliding vane substrate is improved, the stability of an interface is promoted, so that the surface DLC film can stably and durably exert the lubricating performance, the abrasion between the sliding vane and a cylinder body is reduced, and the working condition stability of an air conditioner compressor is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of surface treatment, in particular to a lubricating DLC film, a preparation method thereof, a sliding vane and a compressor. BACKGROUND

[0002] During the operation of the compressor, the contact surface between the sliding vane and the cylinder is a typical friction pair, and its performance directly affects the efficiency and service life of the compressor. By coating a solid lubricating coating on the surface of the sliding vane, the lubricating performance of the sliding vane can be significantly improved, the friction coefficient can be reduced, abnormal wear caused by dry friction or boundary lubrication can be reduced, and the adaptability of the compressor under high load and long period operation conditions can be improved. Diamond-like carbon (DLC) film is an amorphous structure formed by sp 2 -C and sp 3 -C hybridization, has a series of advantages such as high hardness, low friction coefficient, good chemical inertness and the ability to effectively improve the friction and wear performance of the substrate surface. However, the DLC film also has the disadvantages of low toughness, high brittleness and poor thermal stability. The residual stress of the film is high, and the film-substrate adhesion is low, which greatly reduces the service life. The low film-substrate adhesion seriously hinders the application of the DLC film in the sliding vane compressor, so improving the film-substrate adhesion of the DLC film has become the research focus of obtaining high-performance DLC film. SUMMARY

[0003] Therefore, the purpose of the present application is to provide a lubricating DLC film and a preparation method thereof, so that the lubricating DLC film is suitable for the sliding vane of the compressor and has higher adhesion and smaller wear with the sliding vane.

[0004] Another purpose of the present application is to provide a sliding vane based on the lubricating DLC film.

[0005] Another purpose of the present application is to provide a compressor based on the sliding vane.

[0006] In order to achieve all or part of the above purposes, as a first aspect of the present application, a lubricating DLC film is provided, which comprises a Cr layer as a bottom layer, a Cr-C transition layer as an intermediate layer, and a DLC film layer as a surface layer; the content of Cr in the Cr-C transition layer gradually decreases along the direction from the bottom layer to the surface layer, and the content of C gradually increases along the direction from the bottom layer to the surface layer.

[0007] Optionally, the thickness of the DLC film layer is 0.3-0.5 μm, the thickness of the Cr-C transition layer is 0.1-0.2 μm, and the thickness of the Cr layer is 0.1-0.2 μm.

[0008] As a second aspect of the present application, a preparation method of the lubricating DLC film is provided, which comprises: S1. sputtering Cr target on the surface of the substrate to deposit a pure Cr layer; S2. after the deposition of the pure Cr layer, gradually reducing the sputtering power of the Cr target while sputtering the C target and gradually increasing the sputtering power of the C target to deposit a Cr-C transition layer; S3. after the deposition of the Cr-C transition layer, sputtering the C target to deposit a DLC film to obtain the lubricating DLC film.

[0009] Optionally, in S1, the Cr target is sputtered using a HiPIMS magnetron sputtering process, and the HiPIMS magnetron sputtering power is not higher than 5 kW.

[0010] Further optionally, in S2, the sputtering power of the Cr target is gradually reduced to 0, and the sputtering power of the C target is gradually increased from 0, and the sputtering power of the Cr target is reduced to 0 as the end node of the Cr-C transition layer.

[0011] More further optionally, in S2, the sputtering power of the Cr target is uniformly reduced to 0 within 10-25 min, and the sputtering power of the C target is increased by 1 kW synchronously each time the sputtering power of the Cr target is reduced.

[0012] Optionally, the ion source power of the HiPIMS magnetron sputtering process is 0.5-5 kW, the ion source is argon, the negative bias voltage is 100-200 V, the duty cycle is 70%-80%, and the size of the throttle valve is 60%-80%.

[0013] Optionally, in S3, the sputtering power for sputtering the C target to deposit the DLC film is 4-5 kW.

[0014] As a third aspect of the present application, a sliding vane is provided, the surface of the sliding vane in contact with the cylinder body is provided with the lubricating DLC film described in the present application or the lubricating DLC film prepared by the preparation method described in the present application.

[0015] As a fourth aspect of the present application, a compressor is provided, comprising the sliding vane described in the present application.

[0016] The pure Cr layer in the lubricating DLC film of the present application can effectively prevent the diffusion of the sliding vane base element into the DLC film, and help to maintain the purity and performance of the DLC film. On this basis, a transition intermediate layer is formed by the gradient change of the content of Cr and C, the adhesion between the DLC film and the sliding vane base is improved by relying on the chemical affinity of Cr and C, the stability of the interface is promoted, the lubricating performance of the surface DLC film can be stably and durably played, the wear between the sliding vane and the cylinder body is reduced, and the stability of the working condition of the air conditioner compressor is ensured. BRIEF DESCRIPTION OF DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the application, and are incorporated in and constitute a part of this specification, the embodiments of the application, and their description, are to explain the application without imposing any undue limitations thereof; Figure 1 A cross-sectional scanning electron microscope image of a lubricious DLC film of the application deposited on a slide substrate surface is shown; Figure 2 The results of the scratch test of Example 1 and Comparative Examples 1-4 are shown; Figure 3 The results of the tribological test of Example 1 (a) and Comparative Examples 1-4 (b-e) are shown; Figure 4 The results of the Rockwell indentation test of Example 1 (a) and Comparative Examples 1-4 (b-e) are shown. DETAILED DESCRIPTION

[0017] The application discloses a lubricious DLC film, a preparation method thereof, and a slide and a compressor. Those skilled in the art can refer to the content herein and appropriately improve process parameters to realize. It is particularly pointed out that all similar replacements and changes are obvious to those skilled in the art, and they are regarded as included in the application. The products and processes described in the application have been described by preferred embodiments, and relevant personnel can obviously make changes or appropriate changes and combinations to the products and processes described herein without departing from the content, spirit and scope of the application, to realize and apply the technology of the application. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the application.

[0018] It should be noted that in this document, relational terms such as "first" and "second", "step 1" and "step 2", and "a" and "an" and "the" and "one" and "another" and "at least one" and "one or more" and "at least one of", and the like are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a", "comprises...", or "comprising... " does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element. The embodiments in the application and the features in the embodiments can be combined with each other without conflict.

[0019] In the working process of a sliding vane compressor, the sliding vane performs a periodic entraining motion. Such a motion mode requires more stable lubrication performance between the sliding vane and the cylinder body. However, the current DLC film generally pursues the improvement of lubrication performance and hardness, and ignores the bonding performance of the DLC film to the sliding vane substrate, which is difficult to meet the use requirements of the sliding vane of the compressor.

[0020] Based on the current technical status, in a first aspect of the present application, a lubricating DLC film is provided, which comprises a Cr layer as a bottom layer, a Cr-C transition layer as an intermediate layer, and a DLC film layer as a surface layer; the Cr content in the Cr-C transition layer gradually decreases along the direction from the bottom layer to the surface layer, and the C content gradually increases along the direction from the bottom layer to the surface layer.

[0021] In the lubricating DLC film of the present application, the pure Cr layer as the bottom layer can effectively prevent the diffusion of the sliding vane substrate elements into the DLC film, and help to maintain the purity and performance of the film. The Cr-C gradient transition layer is a special design, which is aimed at gradually adjusting the composition of the material from pure chromium to pure carbon, thereby realizing the gradual matching from the crystal structure of Cr to the crystal structure of carbon, reducing the stress and interface problems caused by lattice mismatch; at the same time, the thermal expansion coefficients of Cr and C are different, and the design of the Cr-C gradient transition layer also helps to alleviate the interface stress caused by temperature changes and improve the stability of the DLC film at different temperatures.

[0022] Moreover, Cr and C have a certain chemical affinity, and the gradual transition structure of pure Cr-Cr / C-DLC in the present application helps to improve the bonding of the DLC film to the substrate and promote the stability of the interface.

[0023] In some embodiments of the present application, the bonding force between Cr and C, which has a basic comparable affinity, in the preparation of the lubricating DLC film is compared, and the results show that the bonding force of the gradual transition structure of pure Cr-Cr / C-DLC is better than that of the gradual transition structure of pure Ti-Ti / C-DLC.

[0024] In some embodiments of the present application, the Cr-C transition layer has a thickness that is too thin, has insufficient bonding strength, is prone to peeling, has poor buffering capacity, and is prone to interface cracking; and the transition layer has a thickness that is too thick, which causes stress superposition, leads to overall cracking of the film layer, and also reduces the adhesion. Therefore, in the present application, the thickness of the Cr-C transition layer is 0.1-0.2 μm, for example, 0.10 μm, 0.11 μm, 0.12 μm, 0.13 μm, 0.14 μm, 0.15 μm, 0.16 μm, 0.17 μm, 0.18 μm, 0.19 μm, 0.20 μm, or any point value between any two of them. The transition layer within the thickness range has better buffering capacity, smaller stress, and high bonding strength. Meanwhile, the overall thickness of the Cr-C transition layer and the DLC film layer should not be too thick, as a large amount of residual compressive stress will accumulate during film deposition when the thickness is too thick. When the thickness is too small, the wear resistance is seriously insufficient, the thin film is easily worn out, the substrate is exposed, and the friction coefficient fluctuates greatly. Therefore, in the present application, the thickness of the DLC film layer is 0.3-0.5 μm, for example, 0.3 μm, 0.31 μm, 0.32 μm, 0.33 μm, 0.34 μm, 0.35 μm, 0.36 μm, 0.37 μm, 0.38 μm, 0.39 μm, 0.40 μm, 0.41 μm, 0.42 μm, 0.43 μm, 0.44 μm, 0.45 μm, 0.46 μm, 0.47 μm, 0.48 μm, 0.49 μm, 0.50 μm, or any value between any two of them. Within this thickness range, the overall thickness of the Cr-C transition layer and the DLC film layer is moderate, and the wear resistance and the compressive stress are relatively small. The pure Cr layer of the bottom layer is too thick, which can easily cause peeling due to residual stress and brittle mismatch, and the thickness is too small to ensure the interface transition effect. Therefore, the thickness of the Cr layer is 0.1-0.2 μm, for example, 0.10 μm, 0.11 μm, 0.12 μm, 0.13 μm, 0.14 μm, 0.15 μm, 0.16 μm, 0.17 μm, 0.18 μm, 0.19 μm, 0.20 μm, or any value between any two of them. This range can effectively improve the film layer adhesion and service stability while ensuring coverage and buffering effect.

[0025] In the second aspect of the present application, a preparation method of the lubricated DLC film is provided, comprising: S1. Sputtering a Cr target on the surface of the substrate to deposit a pure Cr layer; S2. After the deposition of the pure Cr layer is completed, gradually reduce the sputtering power of the Cr target, and at the same time, sputter the C target and gradually increase the sputtering power of the C target to deposit a Cr-C transition layer; S3. After the deposition of the Cr-C transition layer is completed, sputter the C target to deposit a DLC film to obtain the lubricated DLC film.

[0026] In some embodiments of the present application, in S1, the Cr target is sputtered by using a HiPIMS magnetron sputtering process on the substrate surface, the deposition time is 10-15 min, and the HiPIMS magnetron sputtering power is not higher than 5 kW. The HiPIMS magnetron sputtering is a high-power pulsed magnetron sputtering, which can generate a high-density ion cloud in an instant, which helps to more efficiently sputter the target and improve the uniformity and density of the Cr-C transition layer. The use of HiPIMS magnetron sputtering for sputtering of the Cr target in the subsequent deposition of the pure Cr layer and the Cr-C transition layer can obtain a dense, smooth, columnar crystal structure-free, stress-controllable, and strongly substrate-bonding film, which can further improve the buffer capacity from pure Cr to Cr-C transition and avoid the occurrence of poor bonding caused by stress; the selection of a sputtering power not higher than 5 kW can ensure that the sputtering power of the Cr target does not have a large change frequency during the subsequent deposition of the Cr-C transition layer, and a too high sputtering power needs to be rapidly reduced during the subsequent deposition of the Cr-C transition layer, which is not conducive to the deposition effect of the transition layer.

[0027] In some embodiments of the present application, in S2, the sputtering power of the Cr target is gradually reduced to 0, and the sputtering power of the C target is gradually increased from 0, and the sputtering power of the Cr target is reduced to 0 as the end node of the Cr-C transition layer. A too fast change frequency of the sputtering power will cause a decrease in plasma density and a too high ion energy, resulting in a decrease in film adhesion, weak interface bonding, stress concentration, and easy cracking and peeling; a too slow change frequency will cause unstable plasma and easy extinction of discharge, resulting in incomplete film. Therefore, in some embodiments of the present application, the sputtering power of the Cr target in S2 is uniformly reduced to 0 within 10-25 min, for example, 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min, 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, or any value between any two of them, and the power can be reduced once every 2-5 min within the time period, preferably with the same interval time for each power reduction, and the sputtering power of the C target is increased by 1 kW synchronously with each reduction of the sputtering power of the Cr target, and a Cr-C transition layer with better buffer capacity and bonding capacity can be obtained within the change frequency range.

[0028] In some embodiments of the present application, the ion source power of the HiPIMS magnetron sputtering process is 0.5-5 kW, the ion source is argon, the negative bias is 100-200 V, the duty cycle is 70%-80%, and the size of the throttle valve is 60%-80%. The magnetron sputtering of the C target can be direct current magnetron sputtering, and the C target is preferably a graphite target.

[0029] In some embodiments of the present application, the sputtering C target deposition of the DLC film in S3 can be direct current magnetron sputtering, the sputtering power is 4-5 kW, the bias voltage is -80 to -120 V, the argon gas inlet amount is 350-400 sccm, the working pressure is maintained at 0.4-0.6 Pa, the rotation speed of the workpiece support turntable during deposition is 1.0-2.0 rpm, and the deposition time is determined according to the DLC film layer on the surface, and is usually adjusted for about 3 hours.

[0030] In some embodiments of the present application, the substrate further comprises a pretreatment step of polishing, polishing, organic solvent cleaning and argon ion glow cleaning on the surface before depositing the lubricating DLC film; wherein the argon ion glow cleaning comprises: After the vacuum is lower than 3.0×10 -3 Pa, argon is introduced to maintain the vacuum degree at 0.4-0.6 Pa, the flow rate of argon is 350-400 sccm, the substrate bias voltage is adjusted to maintain at -700 to -800 V, the duty cycle is 80%-90%, the ion source power is turned on, and the argon ion glow cleaning of the substrate is performed for 15-20 min.

[0031] In a third aspect of the present application, a sliding sheet is provided, wherein the surface of the sliding sheet in contact with the cylinder is deposited with the lubricating DLC film described in the present application or the lubricating DLC film prepared by the preparation method described in the present application. The material of the sliding sheet includes any one of metal, such as cast iron, carbon steel, stainless steel and hard alloy.

[0032] In a fourth aspect of the present application, a compressor is provided, comprising the sliding sheet described in the present application.

[0033] In each group of comparative experiments provided in the present application, unless otherwise specified, the experimental conditions, materials, etc. are kept consistent except for the differences indicated in each group in order to have comparability. In addition, the materials used in the present application can be obtained by market purchase.

[0034] The following further describes a lubricating DLC film and its preparation method, as well as a sliding sheet and a compressor provided in the present application.

[0035] Example 1: (1) Sliding sheet substrate cleaning First, the sliding sheet substrate after polishing and polishing treatment is ultrasonically cleaned in anhydrous ethanol for 20-25 min; then argon ion glow cleaning is performed in a multifunctional DLC film coating device, and the specific method is as follows: the sliding sheet substrate is fixed in the vacuum chamber of the multifunctional DLC film coating device, the vacuum chamber is vacuumed to be lower than 3.0×10 -3After Pa, argon gas is introduced to maintain a vacuum of 0.4~0.6 Pa, with an argon gas flow rate of 350~400 sccm. At the same time, the bias voltage of the sliding substrate is adjusted to maintain it at -700~-800V, and the duty cycle is 80%~90%. The ion source power supply is turned on and the ion source power is set to 1.5kW. The sliding substrate is subjected to argon ion glow discharge cleaning for 15~20 minutes.

[0036] (2) Deposition of pure Cr layer and Cr-C transition layer After the sliding substrate is cleaned by argon ion glow discharge in step (1), the ion source power is adjusted to 0.5kW, argon gas is introduced and the negative bias voltage is adjusted to 100~200V, the duty cycle to 70%~80%, and the throttle valve size to 60%~80%. The HiPIMS magnetron sputtering power is set to 5kW, and the Cr target is sputtered. The pure Cr layer is deposited using HiPIMS high-power pulsed magnetron sputtering for 10-15min, and the thickness of the pure Cr layer is between 0.1~0.2μm. After the pure Cr layer deposition is completed, the HiPIMS sputtering power of the Cr target is uniformly reduced to 0 over 10~25min. At the same time, the DC magnetron sputtering of the graphite target is turned on. Each time the sputtering power of the Cr target is reduced, the DC sputtering power of the graphite target is simultaneously increased by 1kW. The thickness of the Cr-C transition layer is between 0.1~0.2μm.

[0037] (3) Deposition of DLC film After the deposition of the Cr-C transition layer in step (2) is completed, the deposition of the DLC film is carried out. The HiPIMS power supply is turned off, and the power of the DC magnetron sputtering power supply is adjusted to 4~5kW, the substrate bias voltage is -80~-120V, the argon gas inlet flow rate is 350~400sccm, and the working pressure is maintained at 0.4~0.6Pa. During the deposition process, the rotation speed of the workpiece support gantry is 1.0~2.0rpm. The DLC film is deposited using DC magnetron sputtering on a graphite target. The thickness of the DLC film is 0.3~0.5μm. After the vacuum chamber temperature is naturally cooled, the lubricated DLC film described in this application is obtained. The scanning electron microscope image of the cross section is shown in [reference needed]. Figure 1 .

[0038] Figure 1 In this process, the pure Cr layer in the thin film generally exists in crystalline form, that is... Figure 1 The slightly whitish portion of the Cr-C transition layer generally exists in a mixed form of crystalline and amorphous materials, meaning that the degree of crystallinity decreases the further away from the substrate. Therefore, the delamination between the pure Cr layer and the Cr-C transition layer is not very obvious. The total thickness of the pure Cr layer and the Cr-C transition layer is about 260 nm (0.26 μm), and the thickness of the surface DLC film layer is about 400 nm (about 0.4 μm). Figure 1 The thicker bottom layer is a pure Cr substrate.

[0039] Comparative Example 1 This comparative example refers to the method of Example 1, except that the deposition of the Cr-C transition layer is omitted, and the rest is consistent with Example 1: (1) Cleaning of the slide substrate First, the slide substrate after polishing and polishing treatment is ultrasonically cleaned in anhydrous ethanol for 20-25 min; then argon ion glow cleaning is performed in the multi-functional DLC film coating equipment, the specific method is as follows: the slide substrate is fixed in the vacuum chamber of the multi-functional DLC film coating equipment, the vacuum chamber is pumped to a vacuum lower than 3.0x10 -3 After 20 Pa, argon is introduced to maintain the vacuum degree at 0.4-0.6 Pa, the flow rate of argon is 350-400 sccm, and the slide substrate bias is adjusted to-700--800 V, the duty cycle is 80%-90%, the ion source power is turned on, the ion source power is set to 1.5 kW, and the slide substrate is subjected to argon ion glow cleaning for 15-20 min.

[0040] (2) Deposition of pure Cr layer After the slide substrate is subjected to argon ion glow cleaning in step (1), the ion source power is adjusted according to the parameters in Example 1, argon is introduced, and the direct current bias, duty cycle, and throttle valve size are adjusted, the HiPIMS magnetron sputtering power is set to 5 kW, the Cr target is sputtered, and the deposition of the pure Cr layer is performed by HiPIMS high-power pulsed magnetron sputtering, and the deposition time is the same as in Example 1.

[0041] (3) Deposition of DLC film layer After the deposition of the pure Cr layer in step (2) is completed, the deposition of the DLC film layer is directly performed, the HiPIMS power is turned off, the power of the direct current magnetron sputtering source, the slide substrate bias, and the argon inlet amount are adjusted according to the parameters in Example 1, the DLC film layer is deposited by direct current magnetron sputtering of a graphite target, and the vacuum chamber is naturally cooled to obtain a lubricating DLC film without a transition layer.

[0042] Comparative Example 2 This comparative example refers to the method of Example 1, except that Ti is used instead of Cr for deposition, and the rest is consistent with Example 1: (1) Cleaning of the slide substrate First, the slide substrate after polishing and polishing treatment is ultrasonically cleaned in anhydrous ethanol for 20-25 min; then argon ion glow cleaning is performed in the multi-functional DLC film coating equipment, the specific method is as follows: the slide substrate is fixed in the vacuum chamber of the multi-functional DLC film coating equipment, the vacuum chamber is pumped to a vacuum lower than 3.0x10 -3After the pressure is reduced to 0.4-0.6 Pa, argon gas is introduced, the flow rate of argon gas is 350-400 sccm, the bias voltage of the slide substrate is kept at -700 to -800 V, the duty cycle is 80% to 90%, the ion source power is turned on, the ion source power is set at 1.5 kW, and the slide substrate is subjected to argon ion glow cleaning for 15-20 min.

[0043] (2) Deposition of pure Cr layer and Ti-C transition layer After the slide substrate is subjected to argon ion glow cleaning in step (1), the ion source power is adjusted according to the parameters in Example 1, argon gas is introduced, and the direct current bias voltage, duty cycle, and throttle valve size are adjusted as in Example 1. The HiPIMS magnetron sputtering power is set at 5 kW, the Ti target is sputtered, the HiPIMS high-power pulsed magnetron sputtering is used to deposit a pure Ti layer, and the deposition time is the same as in Example 1. After the deposition of the pure Ti layer is completed, the HiPIMS sputtering power of the Ti target is uniformly reduced to 0, the time and frequency of the reduction are the same as in Example 1, and the direct current magnetron sputtering of the graphite target is turned on. When the sputtering power of the Ti target is reduced each time, the direct current sputtering power of the graphite target is simultaneously increased by 1 kW.

[0044] (3) Deposition of DLC film layer After the deposition of the Ti-C transition layer in step (2) is completed, the deposition of the DLC film layer is carried out. The HiPIMS power is turned off, the power of the direct current magnetron sputtering power, the bias voltage of the slide substrate, and the argon gas flow rate are adjusted as in Example 1, the DLC film layer is deposited using the direct current magnetron sputtering of the graphite target, and the vacuum chamber is naturally cooled to obtain a lubricating DLC film with a Ti-C transition layer.

[0045] Comparative Example 3 This comparative example refers to the method of Example 1, except that the magnetron sputtering power and deposition time are changed to form a Cr-C transition layer with an excessively large thickness, and the other conditions are the same as in Example 1. (1) Slide substrate cleaning First, the slide substrate after polishing and polishing treatment is ultrasonically cleaned in anhydrous ethanol for 20-25 min. Then, the slide substrate is subjected to argon ion glow cleaning in a multi-functional DLC film coating device. The specific method is as follows: the slide substrate is fixed in the vacuum chamber of the multi-functional DLC film coating device, the vacuum chamber is evacuated to a pressure lower than 3.0 x 10 -3 After the pressure is reduced to 0.4-0.6 Pa, argon gas is introduced, the flow rate of argon gas is 350-400 sccm, the bias voltage of the slide substrate is kept at -700 to -800 V, the duty cycle is 80% to 90%, the ion source power is turned on, the ion source power is set at 1.5 kW, and the slide substrate is subjected to argon ion glow cleaning for 15-20 min.

[0046] (2) Deposition of pure Cr layer and Cr-C transition layer After the step (1) of performing argon ion glow cleaning on the slide substrate, the ion source power is adjusted according to the parameters in the embodiment 1, the argon gas, negative bias, duty cycle, and throttle valve size are the same as in the embodiment 1, the HiPIMS magnetron sputtering power is set to 5 kW, the Cr target is sputtered, the pure Cr layer is deposited by using the HiPIMS high-power pulsed magnetron sputtering, and the deposition time is the same as in the embodiment 1. After the deposition of the pure Cr layer is completed, the Cr-C transition layer is deposited in the manner as in the embodiment 1, except that the deposition time is extended to 25 min, and the other parameters are the same as in the embodiment 1. Since the deposition time is significantly greater than that in the embodiment 1, the final thickness is greater than the upper limit value 0.2 μm of the thickness of the Cr-C transition layer in the present application.

[0047] (3) Deposition of DLC film layer After the deposition of the Cr-C transition layer in the step (2) is completed, the deposition of the DLC film layer is performed, the HiPIMS power is turned off, the power of the direct current magnetron sputtering source, the bias voltage of the slide substrate, and the argon gas flow rate are adjusted as in the embodiment 1, the DLC film layer is deposited by using the direct current magnetron sputtering graphite target, and the thicker lubricating DLC film of the Cr-C transition layer is obtained after the vacuum chamber is naturally cooled.

[0048] Comparative example 4 The comparative example is performed according to the method in the embodiment 1, except that the magnetron sputtering power and the deposition time are changed to form the film layer with a Cr-C transition layer having a thickness that is too small, and the other parameters are the same as in the embodiment 1. (1) Cleaning of slide substrate First, the slide substrate after polishing and polishing treatment is cleaned in anhydrous ethanol by ultrasonic cleaning for 20-25 min, and then argon ion glow cleaning is performed in the multi-functional DLC film coating equipment. Specifically, the slide substrate is fixed in the vacuum chamber of the multi-functional DLC film coating equipment, the vacuum chamber is evacuated to a vacuum degree lower than 3.0 x 10 -3 Pa, argon gas is introduced to maintain the vacuum degree at 0.4-0.6 Pa, the flow rate of the argon gas is 350-400 sccm, the bias voltage of the slide substrate is adjusted to -700 to -800 V, the duty cycle is 80%-90%, the ion source power is turned on, the ion source power is set to 1.5 kW, and the argon ion glow cleaning of the slide substrate is performed for 15-20 min.

[0049] (2) Deposition of pure Cr layer and Cr-C transition layer After the sliding substrate is cleaned by argon ion glow discharge in step (1), the ion source power is adjusted according to the parameters in Example 1. Argon gas is introduced, negative bias voltage, duty cycle, and throttle valve size are the same as in Example 1. The HiPIMS magnetron sputtering power supply is set to 5kW, and a Cr target is sputtered. Pure Cr layer is deposited using HiPIMS high-power pulsed magnetron sputtering, and the deposition time is the same as in Example 1. After the pure Cr layer deposition is completed, a Cr-C transition layer is deposited in the same manner as in Example 1, except that the deposition time is shortened to 3 minutes. Everything else is the same as in Example 1. Since the deposition time is significantly shorter than in Example 1, the final thickness is less than the lower limit of the Cr-C transition layer thickness of this application, which is 0.1 μm.

[0050] (3) Deposition of DLC film After the deposition of the Cr-C transition layer in step (2) is completed, the deposition of the DLC film is carried out. The HiPIMS power supply is turned off, and the parameters such as the power of the DC magnetron sputtering power supply, the bias voltage of the sliding substrate, and the argon gas intake are adjusted in the same way as in Example 1. The DLC film is deposited by DC magnetron sputtering on a graphite target. After the vacuum chamber temperature cools naturally, a lubricating DLC ​​film with a thinner Cr-C transition layer is obtained.

[0051] Experimental example: (1) Results of the scratch test The lubricated DLC films prepared in Example 1 and the comparative examples were subjected to scratch tests under the same experimental conditions. The results are shown in the figure. Figure 2 ; Depend on Figure 2 It can be seen that the lubricating DLC ​​film in Example 1 begins to show the critical point of plastic deformation at 44.386 N, while the lubricating DLC ​​film in Comparative Example 1 begins to show the critical point of plastic deformation at 15.1 N. The critical points of plastic deformation for Comparative Examples 2, 3, and 4 are 40.3 N, 28.5 N, and 24.2 N, respectively. The experimental results show that the lubricating DLC ​​film provided in this application has a higher bonding force with the sliding substrate. The comparative examples without a Cr-C transition layer, with an excessively thick Cr-C transition layer, or with an excessively thin Cr-C transition layer all fail to achieve good bonding force.

[0052] (2) Tribological Experiment Results Tribological experiments were conducted on the lubricated DLC films prepared in Example 1 and each comparative example under the same experimental conditions. The results are shown in [Figure 1]. Figure 3 ; Depend on Figure 3It can be seen that the wear track of the lubricating DLC ​​film in Example 1 is the narrowest, at 215.01 μm, with a lighter wear track, clear and neat edges, and almost no lip, indicating no serious material damage. In contrast, the lubricating DLC ​​films in the comparative examples all have significantly wider and heavier wear tracks, blurred edges, and obvious lip or material accumulation on both sides, indicating that the material has undergone severe plastic deformation. The experimental results show that the lubricating DLC ​​film provided in this application has superior lubrication performance. The comparative examples without a Cr-C transition layer, with an excessively thick Cr-C transition layer, or with an excessively thin Cr-C transition layer all failed to achieve good lubrication performance.

[0053] (3) Results of Rockwell hardness test indentation The lubricated DLC films prepared in Example 1 and the comparative examples were subjected to Rockwell hardness test indentation under the same experimental conditions. The results are shown in the figure. Figure 4 ; Depend on Figure 4 It can be seen that there is no obvious film peeling or breakage around the indentation of the lubricating DLC ​​film in Example 1, while the films of Comparative Examples 1-4 all showed varying degrees of peeling and breakage in a certain area around the indentation. The experimental results show that the lubricating DLC ​​film of this application has a high interfacial bonding strength with the substrate, is not easy to peel off, and has low stress. However, the comparative examples without Cr-C transition layer, Ti-C transition layer, excessively thick Cr-C transition layer, and excessively thin Cr-C transition layer cannot achieve good interfacial bonding strength.

[0054] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A lubricating DLC ​​film, characterized in that, It includes a bottom Cr layer, a middle Cr-C transition layer, and a top DLC film layer; the Cr content in the Cr-C transition layer gradually decreases from the bottom layer to the top layer, and the C content gradually increases from the bottom layer to the top layer.

2. The lubricating DLC ​​film according to claim 1, characterized in that, The thickness of the DLC film is 0.3~0.5μm, the thickness of the Cr-C transition layer is 0.1~0.2μm, and the thickness of the Cr layer is 0.1~0.2μm.

3. The method for preparing the lubricating DLC ​​film according to claim 1, characterized in that, include: S1. Sputter a Cr target onto the substrate surface to deposit a pure Cr layer; S2. After completing the deposition of the pure Cr layer, gradually reduce the sputtering power of the Cr target, while sputtering the C target and gradually increasing the sputtering power of the C target to deposit the Cr-C transition layer. S3. After completing the Cr-C transition layer deposition, a DLC film is deposited by sputtering a C target to obtain the lubricating DLC ​​film.

4. The preparation method according to claim 3, characterized in that, In S1, Cr target material is sputtered on the substrate surface using HiPIMS magnetron sputtering process, and the power of HiPIMS magnetron sputtering power supply is not higher than 5kW.

5. The preparation method according to claim 3 or 4, characterized in that, In S2, the sputtering power of the Cr target is gradually reduced to 0, while the sputtering power of the C target is gradually increased from 0. The end point of the Cr-C transition layer is when the sputtering power of the Cr target is reduced to 0.

6. The preparation method according to claim 5, characterized in that, In S2, the sputtering power of the Cr target material is uniformly reduced to 0 within 10~25 minutes. Each time the sputtering power of the Cr target material decreases, the sputtering power of the C target material increases by 1kW.

7. The preparation method according to claim 4, characterized in that, The HiPIMS magnetron sputtering process uses an ion source with a power of 0.5~5kW, an argon gas source, a negative bias of 100~200V, a duty cycle of 70%~80%, and a throttle valve size of 60%~80%.

8. The preparation method according to claim 3, characterized in that, The sputtering power of the C target for depositing DLC ​​thin films in S3 is 4~5kW.

9. A slider, characterized in that, The surface of the slide that contacts the cylinder is deposited with the lubricating DLC ​​film as described in claim 1 or 2, or with the lubricating DLC ​​film prepared by any one of claims 3-8.

10. A compressor, characterized in that, Includes the slider as described in claim 9.

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