Wear-resistant surface as well as preparation method and application thereof

Abstract

The invention discloses a wear-resistant surface and a preparation method and application thereof.The preparation method comprises the steps that firstly, surface nitriding strengthening is conducted on a substrate, and a nitriding layer is formed; then preparing a CrN / CrCN / CrC transition layer on the basis of the nitriding layer; the nanometer mutual diffusion layer is prepared on the surface of the transition layer through high-energy particle bombardment; and finally depositing a tetrahedral amorphous carbon layer. Therefore, a transition structure of element composition and hardness gradient is formed, and the difference of mechanical properties of the tetrahedral amorphous carbon layer and the substrate can be reduced, so that the binding force of the coating is enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wear-resistant surfaces, and in particular to a wear-resistant surface and a method for preparing and using the same. BACKGROUND

[0002] A DLC coating is an amorphous carbon film, and the carbon atoms therein mainly have two bonding structures of sp 2 and sp 3 hybridization, and thus have the properties of both graphite and diamond. The sp 2 bonding is similar to the carbon bonding structure in graphite, and is arranged in a planar hexagonal shape, with low hardness but good electrical conductivity; the sp 3 bonding is similar to the carbon bonding structure in diamond, and is arranged in a tetrahedral shape, with stable structure and high hardness. When the proportion of sp 2 bonding is higher, the DLC coating has properties more like graphite; when the proportion of sp 3 bonding is higher, the coating has properties more like diamond, with higher hardness, but also usually means higher internal stress. A Ta-C coating (tetrahedral amorphous carbon layer) is a type of DLC coating, and has more than 70% of sp 3 hybridization in its structure, and thus has extremely high hardness. It is widely used in fields requiring high wear resistance and high hardness, such as cutting tools, engine parts, and aviation structural parts.

[0003] The formation of sp 3 bonding requires the carbon atoms to have very high energy, and thus in the preparation process, the coating will accumulate internal stress due to high-energy particle bombardment and energy accumulation. Under the action of external load, the difference in mechanical properties between the coating and the substrate will further amplify the negative effects of internal stress, and in the use process of the coating, the coating is prone to collapse and peeling. The hard Ta-C particles that have peeled off will be sandwiched between the counter- friction pairs, which will exacerbate the wear of the two, causing the failure of the parts.

[0004] Therefore, it is urgent to improve the adhesion between the Ta-C coating and the substrate.

[0005] It should be noted that the above statements are only used to provide background technical information related to the present application, and do not necessarily constitute prior art. SUMMARY

[0006] In a first aspect, the present application provides a wear-resistant surface, comprising: a substrate, the substrate comprising at least one of pure metal or alloy material; a nitriding layer, the nitriding layer being located on one side of the substrate; a transition layer, the transition layer being located on one side of the nitriding layer away from the substrate, the transition layer comprising a CrN layer, a CrCN layer and a CrC layer arranged in layers along the direction away from the substrate; a nanometer interdiffusion layer, the nanometer interdiffusion layer being located on one side of the transition layer away from the nitriding layer; and a tetrahedral amorphous carbon layer, the tetrahedral amorphous carbon layer being located on one side of the nanometer interdiffusion layer away from the transition layer. Thus, by forming a transition structure of element composition and hardness gradient, the difference in mechanical properties between the tetrahedral amorphous carbon layer and the substrate is reduced, thereby enhancing the bonding strength between the tetrahedral amorphous carbon layer and the substrate, and the wear resistance of the wear-resistant surface is significantly improved.

[0007] In some embodiments of the present application, the thickness of the nitriding layer is 50-300 μm. Thus, the hardness, wear resistance and corrosion resistance of the substrate are improved, and the difference in mechanical properties between the tetrahedral amorphous carbon layer and the substrate is reduced.

[0008] In some embodiments of the present application, the thickness of the CrN layer is 200-1000 nm; and / or, the thickness of the CrCN layer is 200-1000 nm; and / or, the thickness of the CrC layer is 200-1000 nm. Thus, a transition of element and hardness gradient is formed from the substrate to the tetrahedral amorphous carbon layer, thereby reducing the risk of peeling of the tetrahedral amorphous carbon layer.

[0009] In some embodiments of the present application, the thickness of the nanometer interdiffusion layer is 2-30 nm. Thus, the bonding force of the CrC layer and the tetrahedral amorphous carbon layer is enhanced.

[0010] In some embodiments of the present application, the thickness of the tetrahedral amorphous carbon layer is 300-1500 nm. Thus, the tetrahedral amorphous carbon layer has both hardness and bonding strength.

[0011] In some embodiments of the present application, the nitriding layer comprises Fe3N, Fe4N and a solid solution of nitrogen in a-Fe. Thus, the hardness of the substrate surface is greatly improved, and a diffusion strengthening layer is formed, providing strong support for the deposition of the tetrahedral amorphous carbon layer.

[0012] In some embodiments of the present application, the ratio of sp 3 The ratio of hybrid carbon atoms to the total number of carbon atoms is 70-90%. Thus, the hardness of the wear-resistant surface is improved.

[0013] In some embodiments of the present application, the hardness of the tetrahedral amorphous carbon layer is a, the hardness of the transition layer is b, the hardness of the nitriding layer is c, and the hardness of the substrate is d, a > b > c > d; wherein a is 25 GPa to 60 GPa; and / or, b is 15 GPa to 30 GPa; and / or, c is 10 GPa to 20 GPa; and / or, d is 4 GPa to 10 GPa. Thus, a hardness gradient transition can be formed between the substrate and the tetrahedral amorphous carbon layer, thereby reducing the difference in mechanical properties between the substrate and the tetrahedral amorphous carbon layer.

[0014] In a second aspect of the present application, a method for preparing a wear-resistant surface is provided, comprising: performing ion nitriding treatment on a substrate to obtain a nitriding layer, the substrate comprising at least one of pure metal or alloy material; sequentially depositing a CrN layer, a CrCN layer and a CrC layer on a side of the nitriding layer away from the substrate by arc ion plating to obtain a transition layer; performing argon ion bombardment treatment on the transition layer to obtain a nano-interdiffusion layer; depositing a tetrahedral amorphous carbon layer on a side of the nano-interdiffusion layer away from the transition layer by magnetic filter cathode arc deposition to obtain the wear-resistant surface. The present application prepares a nitriding layer on the surface of the substrate by ion nitriding treatment, and designs a transition layer matched with the element composition of the substrate. The arc ion plating method is used to prepare a transition layer with high bonding force. An element and hardness gradient transition is formed from the substrate to the tetrahedral amorphous carbon layer, and a nano-interdiffusion layer is prepared at the interface between the tetrahedral amorphous carbon layer and the transition layer, thereby improving the bonding force between the tetrahedral amorphous carbon layer and the substrate.

[0015] In some embodiments of the present application, the bias voltage of the arc ion plating is 50 V to 300 V, the gas pressure is 1 Pa to 2 Pa, and the temperature is 200 ℃ to 500 ℃. Thus, it is beneficial to reduce the interface defects of the transition layer and improve the strength of the transition layer.

[0016] In some embodiments of the present application, the time of the argon ion bombardment treatment is 30 min to 60 min. Thus, the thickness of the nano-interdiffusion layer can be controlled, and the bonding force between the CrC layer and the tetrahedral amorphous carbon layer can be enhanced.

[0017] In some embodiments of the present application, the bias voltage of the magnetic filter cathode arc deposition is 100 V to 1500 V, and the temperature is 50 ℃ to 100 ℃. Thus, it is beneficial to improve the hardness and uniformity of the tetrahedral amorphous carbon layer, and the deposition rate is relatively high.

[0018] In a third aspect of the present application, the wear-resistant surface of the first aspect of the present application or the wear-resistant surface prepared by the method of the second aspect of the present application is applied in the fields of machining tools, automobiles, and aerospace. Thus, the wear-resistant surface can be applied in fields requiring high wear resistance and high hardness, and has a wide application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0019] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:

[0020] Figure 1 Structure diagram of wear-resistant surface for one embodiment of the present application.

[0021] Figure 2 Elemental gradient transition diagram of wear-resistant surface prepared for Example 1 of the present application.

[0022] Figure 3 a) Microhardness diagram of wear-resistant surface prepared for Example 1, Comparative Example 1 to Comparative Example 3 of the present application, b) Nanohardness diagram and elastic modulus diagram of wear-resistant surface prepared for Example 1, Comparative Example 1 to Comparative Example 3 of the present application.

[0023] Figure 4 Bonding force diagram of wear-resistant surface prepared for Comparative Example 4 of the present application.

[0024] Figure 5 Cross-sectional HRTEM morphology diagram of nitrided layer-CrN / CrCN / CrC transition layer-nanomutual diffusion layer-Ta-C coating for Example 1 of the present application.

[0025] Figure 6 Bonding force diagram of wear-resistant surface prepared for Comparative Example 6 of the present application and wear-resistant surface prepared for Example 1.

[0026] Figure 7 Proportion of sp 3 bond in Ta-C coating for Example 1 of the present application.

[0027] Figure 8 Friction coefficient and wear morphology diagram of wear-resistant surface prepared for Example 1 of the present application and wear-resistant surface prepared for Comparative Example 1.

[0028] BRIEF DESCRIPTION OF DRAWINGS

[0029] 1 - substrate, 2 - nitrided layer, 3 - transition layer, 4 - nanomutual diffusion layer, 5 - tetrahedral amorphous carbon layer, 6 - CrN layer, 7 - CrCN layer, 8 - CrC layer. DETAILED DESCRIPTION

[0030] Embodiments of the present application are described in detail below with reference to the attached drawing figures, but it is to be noted that the application is not limited to the described embodiments but can be carried out in various ways. For example, the description below is not intended to exclude that details of the described embodiments can be combined, or that features of the described embodiments can be interchanged or replaced by alternatives having the same or similar function. Furthermore, the drawing figures and the following description are provided for a better understanding of the present application, but are not intended to limit the subject matter described by the claims.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application; and various parameters recited in the specification of the present application can be measured according to any method known in the art (e.g., can be tested according to the methods given in the examples of the present application), unless otherwise stated.

[0032] The terms "comprising" and "having," and any variations thereof, as used in the specification and claims of this application, are open-ended transitional phrases, i.e., including, but not limited to, whatever follows the term.

[0033] In the description of the present application, all numbers disclosing the application are approximate. The numerical values of each numerical parameter can vary up to 10% or as understood by those skilled in the art, such as 1%, 2%, 3%, 4%, or 5%.

[0034] The ranges disclosed herein are intended to include both endpoints and intervening values, unless explicitly indicated otherwise. For example, a range from 60-120 and a range from 80-110 should be interpreted to include not only 60-120 and 80-110, but also the range from 60 to 110, the range from 80 to 120, as well as any other intervening ranges. Further, a minimum range value of 1 and a maximum range value of 3, for example, should be interpreted to include not only 1-3, but also the ranges 1-3, 1-2, 2-3, as well as any other intervening ranges. In this application, unless otherwise indicated, a numerical range "a-b" means and is equivalent to the range of any real combinations of values between the lower value "a" and the upper value "b" in which "a" and "b" are both real numbers. For example, the numerical range "0-5" means and is equivalent to all the real numbers between "0-5" have been listed herein, and "0-5" is just a shorthand notation for these numerical combinations. In addition, when a parameter is stated to be an integer ≥ 2, it is equivalent to disclose that the parameter is, for example, integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0035] In the description of the present application, "A and / or B" can include any one of the case of A alone, the case of B alone, the case of A and B, where A, B are used for example only, which can be any technical features connected by "and / or" in the present application.

[0036] In the present application, the order of the steps written does not mean the strict execution order and constitute any limitation to the implementation process, and the specific execution order of the steps should be determined by its function and possible inherent logic. If not specifically stated, all the steps of the present application can be performed sequentially or randomly, and the sequential performance is preferred. For example, the method comprises steps (a) and (b), which means that the method can comprise sequentially performed steps (a) and (b), or sequentially performed steps (b) and (a). For example, the method also comprises step (c), which means that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0037] If not specifically stated, all the embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions.

[0038] If not specifically stated, all the technical features and optional technical features of the present application can be combined with each other to form new technical solutions.

[0039] Ta-C coating is one of DLC coatings, which sp 3 The bond ratio is above 70%, so the mechanical properties are very close to diamond, the hardness can reach 50GPa-80GPa, and it has good wear resistance and is widely used in machining tools, automobiles, aerospace and other industries. Due to its special structure, the internal stress is very large, and the coating is easy to peel off from the substrate during use. The hard particles that fall off can greatly damage the substrate material and cause more serious wear. Therefore, improving the adhesion of the Ta-C coating is a problem that needs to be solved.

[0040] In the first aspect of the present application, the present application provides a wear-resistant surface, referring to Figure 1 The wear-resistant surface comprises a substrate 1, the substrate comprises at least one of pure metal or alloy material; a nitriding layer 2 located on one side of the substrate; a transition layer 3 located on the side of the nitriding layer away from the substrate, the transition layer comprises a CrN layer 6, a CrCN layer 7 and a CrC layer 8 arranged in layers along the direction away from the substrate; a nanometer interdiffusion layer 4 located on the side of the transition layer away from the nitriding layer; a tetrahedral amorphous carbon layer (Ta-C coating) 5 located on the side of the nanometer interdiffusion layer away from the transition layer. Among them, the setting of the nitriding layer can improve the hardness of the substrate, the transition layer is designed as CrN / CrCN / CrC, the deposition of the CrN layer directly connects with the nitriding layer, reducing the deposition of the conventional soft single metal layer, and the hardness transition is more reasonable; the nanometer interdiffusion layer nests the CrC layer of the outermost layer of the transition layer and the pure carbon structure of the tetrahedral amorphous carbon layer together, increasing the adhesion between the CrC layer and the tetrahedral amorphous carbon layer.

[0041] Based on the substrate element (high Cr element content) and the hardness characteristics, the present application sets a nitriding layer, a transition layer and a nanometer interdiffusion layer between the substrate and the tetrahedral amorphous carbon layer, and forms an element composition and hardness gradient transition structure, which can reduce the difference in mechanical properties between the tetrahedral amorphous carbon layer and the substrate, thereby enhancing the bonding strength between the tetrahedral amorphous carbon layer and the substrate, and significantly improving the wear resistance of the wear-resistant surface.

[0042] In some embodiments of the present application, the thickness of the nitriding layer is 50-300 μm, for example, it can be 50 μm, 80 μm, 100 μm, 130 μm, 150 μm, 180 μm, 200 μm, 230 μm, 250 μm, 280 μm or 300 μm, etc. Thus, it is beneficial to improve the hardness of the substrate, and further reduce the difference in mechanical properties between the tetrahedral amorphous carbon layer and the substrate.

[0043] In some embodiments of the present application, the thickness of the CrN layer is 200-1000 nm, for example, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm or 1000 nm, etc.

[0044] In some embodiments of the present application, the thickness of the CrCN layer is 200-1000 nm, for example, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm or 1000 nm, etc.

[0045] In some embodiments of the present application, the thickness of the CrC layer is 200-1000 nm, for example, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm or 1000 nm, etc.

[0046] With the above transition layer structure design, a gradient transition of the element and hardness from the substrate to the tetrahedral amorphous carbon layer is realized, thereby facilitating the reduction of the risk of peeling of the tetrahedral amorphous carbon layer.

[0047] In some embodiments of the present application, the thickness of the nanometer interdiffusion layer is 2-30 nm, for example, 2 nm, 5 nm, 8 nm, 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, 22 nm, 25 nm, 28 nm or 30 nm, etc. It can be understood that the thickness of the nanometer interdiffusion layer depends on the time of high-energy argon particle bombardment and high-energy carbon particle deposition before the deposition of the tetrahedral amorphous carbon layer, and the longer the time, the greater the thickness. The nanometer interdiffusion layer nests the CrC layer of the outermost layer of the transition layer and the pure carbon structure of the Ta-C layer together, increasing the bonding force of the CrC layer and the tetrahedral amorphous carbon layer. The proportion of C element in the CrC layer itself is about 50%, and directly depositing the tetrahedral amorphous carbon layer with pure C structure on the surface of the transition layer will cause poor interlayer bonding force due to the difference in stress, thermal expansion coefficient, etc. between the two. The nanometer interdiffusion layer can enhance the transition between the two and improve the bonding force. The thickness of the nanometer interdiffusion layer is in the above range, which is conducive to enhancing the bonding force of the CrC layer and the tetrahedral amorphous carbon layer.

[0048] In some embodiments of the present application, the thickness of the tetrahedral amorphous carbon layer is 300-1500 nm, for example, 300 nm, 500 nm, 700 nm, 900 nm, 1100 nm, 1300 nm or 1500 nm, etc. Thus, the tetrahedral amorphous carbon layer has both hardness and bonding strength.

[0049] In some embodiments of the present application, the nitriding layer comprises Fe3N, Fe4N and solid solution of nitrogen in a-Fe. Thus, the hardness of the substrate surface is greatly improved, forming a diffusion strengthening layer, which provides strong support for the deposition of the tetrahedral amorphous carbon layer.

[0050] In some embodiments of the present application, the ratio of sp 3 The ratio of hybrid carbon atoms to the total number of carbon atoms is 70% to 90%, for example, it can be 70%, 75%, 80%, 85% or 90%, etc. It can be understood that the ratio is the number of carbon atoms in the tetrahedral amorphous carbon layer compared to sp 3 / (sp 2 +sp 3 ). Thus, it is beneficial to improve the hardness of the wear-resistant surface.

[0051] In some embodiments of the present application, the hardness of the tetrahedral amorphous carbon layer is a, the hardness of the transition layer is b, the hardness of the nitriding layer is c, and the hardness of the substrate is d, a > b > c > d; wherein a is 25GPa to 60GPa, for example, it can be 25GPa, 30GPa, 35GPa, 40GPa, 45GPa, 50GPa, 55GPa or 60GPa, etc.; and / or, b is 15GPa to 30GPa, for example, it can be 15GPa, 20GPa, 25GPa or 30GPa, etc.; and / or, c is 10GPa to 20GPa, for example, it can be 10GPa, 12GPa, 14GPa, 16GPa, 18GPa or 20GPa, etc.; and / or, d is 4GPa to 10GPa, for example, it can be 4GPa, 5GPa, 6GPa, 7GPa, 8GPa, 9GPa or 10GPa, etc. It can be understood that the significance of the nanometer interdiffusion layer is to have an interactive embedding of the transition layer surface and the bottom of the tetrahedral amorphous carbon layer, which is a change in structure. Since it is too micro, its hardness cannot be obtained, and the present application does not make specific limitations. Thus, a hardness gradient transition can be formed between the substrate and the tetrahedral amorphous carbon layer, thereby reducing the difference in mechanical properties between the substrate and the tetrahedral amorphous carbon layer, and improving the overall bonding strength of the wear-resistant surface.

[0052] In a second aspect of the present application, a method for preparing a wear-resistant surface is provided, comprising:

[0053] S1: ion nitriding treatment is performed on the substrate to obtain a nitriding layer.

[0054] In some embodiments of the present application, the substrate comprises at least one of pure metal or alloy material, for example, it can be steel, synthetic steel or iron-based metal material. Thus, rigid support can be provided to enable the tetrahedral amorphous carbon layer to withstand higher contact stress.

[0055] In order to improve the support of the substrate to the high-hardness tetrahedral amorphous carbon layer, the ion nitriding method is used to strengthen the substrate in this step. After ion nitriding, nitrides such as Fe3N, Fe4N and solid solution of nitrogen in α-Fe are formed on the surface, the surface hardness is greatly improved, and a diffusion strengthening layer is formed to provide strong support for the deposition of the coating.

[0056] The ion nitriding treatment is a plasma chemical heat treatment method, which is one of the common ways for metal surface modification, and can greatly improve the hardness, wear resistance and corrosion resistance of the metal surface. Its principle is that the active nitrogen particles are obtained by decomposing the nitrogen-containing gas through glow discharge, that is, the gas is ionized by applying a voltage between the positive and negative electrodes in the furnace, so that the gas is converted into a plasma state. Under the acceleration of the electric field, the active nitrogen particles bombard the workpiece surface, heat the workpiece and activate the surface metal. Finally, various nitrogen-containing particles are adsorbed and diffused on the workpiece surface, thereby forming a nitride layer and a solid solution diffusion layer of nitrogen on the workpiece surface, and forming a hardness gradient transition from the substrate to the surface in terms of mechanical properties, thereby providing support for the deposition of the coating.

[0057] Specific preparation process can be: using an ion nitriding furnace, treating the sample under the following parameters: temperature 400℃-600℃, part negative bias 600V-800V, diffusion pressure 200Pa-400Pa, nitrogen to hydrogen ratio 1:2-1:4, diffusion time 3h-8h, to obtain a certain hardness and nitriding layer depth.

[0058] It can be understood that the ion nitriding treatment is used as a pretreatment process in the present application, in order to utilize the hardening layer (Fe, N compound) formed by ion nitriding to cooperate with the transition layer to provide hardness gradient transition and element composition transition for the tetrahedral amorphous carbon layer. The specific parameters are not limited.

[0059] S2: sequentially depositing a CrN layer, a CrCN layer and a CrC layer on the side of the nitriding layer away from the substrate by arc ion plating, to obtain a transition layer.

[0060] In some embodiments of the present application, the bias voltage of the arc ion plating is 50V-300V (such as 50V, 100V, 150V, 200V, 250V or 300V, etc.), the gas pressure is 1Pa-2Pa (such as 1Pa, 1.2Pa, 1.4Pa, 1.6Pa, 1.8Pa or 2Pa, etc.), and the temperature is 200℃-500℃ (such as 200℃, 250℃, 300℃, 350℃, 400℃, 450℃ or 500℃, etc.). Thus, it is beneficial to reduce the interface defects of the transition layer and improve the strength of the transition layer.

[0061] In the present application, the preparation method of the transition layer is arc ion plating technology. The principle of arc ion plating is to generate high-density metal plasma (including ions, atoms and droplets) by large current induced arc discharge on the surface of the target material. These high-energy ions accelerate deposition under the action of negative bias of the substrate, forming a high-bonding thin film. In the present application, high-purity Cr target (99.999%) is used as the excitation source, and nitrogen and methane are used as the reaction gas during the process. The transition layer structure is designed as CrN / CrCN / CrC. Based on the concept of element and hardness gradient transition, the deposition of CrN layer and nitriding layer is connected, which reduces the deposition of conventional soft single metal layer and makes the hardness transition more reasonable. Thus, the element composition and hardness gradient transition from the substrate to the surface of the transition layer are formed. The transition layer further improves the hardness and provides support for the deposition of tetrahedral amorphous carbon layer.

[0062] The specific preparation process is as follows:

[0063] (1) After polishing the surface of the sample treated by ion nitriding, ultrasonic cleaning with anhydrous ethanol and acetone for 10 min each, loading the furnace, and rotating the workpiece with the rotating frame at 5 rpm to 10 rpm;

[0064] (2) The cavity is vacuumed to 5x10 -4 Pa below, then heated to 200℃ to 500℃, and vacuumed again to 5x10 -4 Pa below;

[0065] (3) Glow cleaning. Introduce 100sccm to 300sccm of argon, maintain the cavity pressure at 1Pa to 2Pa, set the pulse bias to 500V to 1000V, the duty cycle to 50% to 70%, and perform glow cleaning for 30min to 60min;

[0066] (4) Ion etching. Set the argon flow to 50sccm to 80sccm, the pressure to 0.5Pa to 0.8Pa, turn on the arc Cr target, and set the target current to 70A to 100A. In this state, ion etching is performed for 10min to 20min;

[0067] (5) Depositing CrN layer. Set the bias to 50V to 300V, turn off the argon, introduce 300sccm to 600sccm of nitrogen, and maintain the pressure at 1Pa to 2Pa. In this state, deposit the CrN layer for 10min to 60min;

[0068] (6) Depositing a CrCN layer. The bias voltage is maintained at 50-300 V, the nitrogen flow rate is reduced to 150-450 sccm, 50-150 sccm of methane and 10-30 sccm of argon are introduced, the pressure is maintained at 1-2 Pa, and the deposition is performed for 2.5-10 min. The nitrogen flow rate is alternately reduced, the methane flow rate is kept unchanged, and the argon flow rate is increased. Finally, the nitrogen flow rate is set to 50-150 sccm, the methane flow rate is set to 50-150 sccm, and the argon flow rate is set to 30-90 sccm. After adjustment in each stage, the deposition is performed for 2.5-10 min.

[0069] (7) Depositing a CrC layer. The bias voltage is maintained at 50-300 V, the nitrogen is turned off, the methane flow rate is maintained at 50-150 sccm, 50-150 sccm of argon is introduced, the pressure is maintained at 1-2 Pa, and the CrN layer is deposited in this state for 10-60 min.

[0070] (8) Turning off the Cr target, turning off the gas switch, and turning off the heating, and waiting for the sample to cool.

[0071] S3: Argon ion bombardment treatment is performed on the transition layer to obtain a nanometer interdiffusion layer.

[0072] Before depositing the tetrahedral amorphous carbon layer, the surface atoms of the transition layer are activated by high-energy argon ion bombardment to form a nanometer interdiffusion layer at the interface, thereby reducing the surface roughness of the transition layer deposited by arc ion plating and improving the adhesion between the tetrahedral amorphous carbon layer and the transition layer.

[0073] In some embodiments of the present application, the argon ion bombardment treatment is performed for 30-60 min, for example, 30 min, 40 min, 50 min, or 60 min. In this way, the thickness of the nanometer interdiffusion layer can be controlled, and the adhesion between the CrC layer and the tetrahedral amorphous carbon layer can be enhanced.

[0074] The specific preparation process of the argon ion bombardment treatment is as follows:

[0075] The furnace is vacuumed to 5x10 -4 Pa, the furnace temperature is heated to 50-100℃, 100-300 sccm of argon is introduced, the pressure is maintained at 1-2 Pa, the sample pulsed negative bias is set to 2000-2500 V, and the duty cycle is 5%. In this state, the argon particle bombardment is performed for 30-60 min.

[0076] It should be noted that the nanometer interdiffusion layer is a state of phase mixing, including Cr and C elements on the surface of the transition layer and C elements of the tetrahedral amorphous carbon layer, both the crystal structure of CrC and the amorphous structure of the tetrahedral amorphous carbon layer.

[0077] S4: depositing a tetrahedral amorphous carbon layer on the side of the nanometer interdiffusion layer away from the transition layer by magnetic filtered cathodic arc deposition, to obtain a wear-resistant surface.

[0078] In some embodiments of the present application, the bias voltage of the magnetic filtered cathodic arc deposition is 100V-1500V (such as 100V, 300V, 500V, 700V, 900V, 1100V, 1300V or 1500V, etc.), and the temperature is 50℃-100℃ (such as 50℃, 60℃, 70℃, 80℃, 90℃ or 100℃, etc.). In this way, the hardness and uniformity of the tetrahedral amorphous carbon layer can be improved, and the deposition rate is relatively high.

[0079] The magnetic filtered cathodic arc deposition technology is an advanced physical vapor deposition method. High ionization rate metal plasma is generated by a cathodic arc evaporation source, and large particles and neutral particles are filtered out by using an electromagnetic field, so that a dense, smooth and high-quality thin film is deposited on the surface of the substrate. This technology combines the high ionization rate of the cathodic arc and the purification effect of the magnetic filtering, significantly reduces the droplet defects in the traditional arc deposition, and has the advantages of high film quality and low temperature preparation.

[0080] The specific preparation process of the magnetic filtered cathodic arc deposition is as follows:

[0081] (1) Use a graphite target (99.999%) as a carbon source. Close the argon, maintain the gas pressure at 1.5x10 -4 Pa, turn on the graphite target, set the target current to 50A-80A, and the filtering coil current to 8A-10A. Set the sample pulse negative bias to 1500V-2000V, the duty cycle to 5%, and the deposition time to 30min-60min. Reduce the sample negative bias to 100V-1500V, and the deposition time to 60min-180min.

[0082] (2) After deposition, turn off the graphite target, and after cooling, open the furnace to obtain a wear-resistant surface strengthened by ion nitriding-CrN / CrCN / CrC transition layer-nanometer interdiffusion layer-Ta-C.

[0083] In the present application, a nitriding layer is prepared on the surface of the substrate by ion nitriding treatment, and a transition layer matched with the element composition of the substrate is designed. A high-bonding-force transition layer is prepared by the method of arc ion plating, an element and hardness gradient transition is formed from the substrate to the tetrahedral amorphous carbon layer, and a nanometer interdiffusion layer is prepared at the interface between the tetrahedral amorphous carbon layer and the transition layer, so as to improve the bonding force between the tetrahedral amorphous carbon layer and the substrate.

[0084] In the third aspect of the present application, the present application provides the application of the wear-resistant surface of the first aspect of the present application or the wear-resistant surface prepared by the method of the second aspect of the present application in the field of machining tools, automobiles and aerospace. Thus, the wear-resistant surface can be applied to the field requiring high wear resistance and high hardness, and has a wide application prospect.

[0085] The above description of various embodiments tends to emphasize the differences between various embodiments, and the same or similar parts can be referred to each other, and will not be described herein for the sake of brevity.

[0086] The scheme of the present application will be described below through specific examples. It should be noted that the following examples are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. If the specific technology or condition is not specified in the examples, the technology or condition described in the literature in the art or according to the product instruction is used. If the reagent or instrument is not specified by the manufacturer, it is a conventional product that can be obtained by purchase.

[0087] Example 1

[0088] 1. Preparation of nitriding layer:

[0089] The sample of 8Cr4Mo4V steel was treated in an ion nitriding furnace at a temperature of 500℃, a part negative bias of 700V, a diffusion pressure of 300Pa, a ratio of nitrogen to hydrogen of 1:3, and a diffusion time of 5h. After treatment, the surface hardness of the sample reached 14GPa, and the thickness of the nitriding layer was 150μm.

[0090] 2. Preparation of CrN / CrCN / CrC transition layer:

[0091] The preparation method of the transition layer is arc ion plating technology, using high-purity Cr target (99.999%) as the excitation source, and using nitrogen and methane as the reaction gas during the process. The specific preparation process is as follows:

[0092] (1) After polishing the surface of the sample treated by ion nitriding, ultrasonic cleaning with anhydrous ethanol and acetone for 10min each, loading the furnace, and rotating the workpiece with the rotating frame at 8rpm;

[0093] (2) The cavity is vacuumed to below 5×10 -4 Pa, then heated to 300℃, and vacuumed again to below 5×10 -4 Pa;

[0094] (3) Glow cleaning. Introduce 150sccm of argon, maintain the cavity pressure at 1Pa, set the pulse bias to 800V, the duty cycle to 70%, and perform glow cleaning for 60min;

[0095] (4) Ion etching. The argon flow rate was set to 80 sccm, the pressure was set to 0.6 Pa, the arc Cr target was turned on, the target current was set to 80 A, and ion etching was performed in this state for 10 min;

[0096] (5) Depositing a CrN layer. The bias voltage was set to 150 V, the argon was turned off, 300 sccm of nitrogen was introduced, the pressure was maintained at 1 Pa, and a CrN layer was deposited in this state for 60 min;

[0097] (6) Depositing a CrCN layer. The bias voltage was maintained at 150 V, the nitrogen flow rate was reduced to 300 sccm, 100 sccm of methane and 10 sccm of argon were introduced, the pressure was maintained at 1 Pa, and deposition was performed for 2.5 min; the nitrogen flow rate was alternately reduced, the methane flow rate was kept constant, and the argon flow rate was increased, and finally the nitrogen flow rate was set to 100 sccm, the methane flow rate was set to 100 sccm, and the argon flow rate was set to 90 sccm, and deposition was performed for 2.5 min after each adjustment.

[0098] (7) Depositing a CrC layer. The bias voltage was maintained at 150 V, the nitrogen was turned off, the methane flow rate was maintained at 100 sccm, 100 sccm of argon was introduced, the pressure was maintained at 1 Pa, and a CrN layer was deposited in this state for 2.5 min;

[0099] (8) Turning off the Cr target, turning off the gas switch, and turning off the heating, and waiting for the sample to cool.

[0100] 3. Preparation of a nanometer interdiffusion layer:

[0101] The furnace was vacuumed to 5×10 -4 Pa, the furnace temperature was heated to 100℃, 150 sccm of argon was introduced, the pressure was maintained at 1 Pa, the pulsed negative bias of the sample was set to 2000 V, the duty cycle was 5%, and argon particle bombardment was performed in this state for 30 min to form a nanometer interdiffusion layer.

[0102] 4. Preparation of a Ta-C coating:

[0103] (1) Depositing a Ta-C layer. A graphite target (99.999%) was used as the carbon source by using a magnetic filter cathode arc technique. The argon was turned off, the pressure was maintained at 1.5×10 -4 Pa, the graphite target was turned on, the target current was set to 60 A, and the filter coil current was 10 A. The pulsed negative bias of the sample was set to 1500 V, the duty cycle was 5%, and the deposition time was 30 min. The negative bias of the sample was reduced to 1000 V, and the deposition time was 150 min.

[0104] (2) After deposition, the graphite target was turned off, the furnace was opened after cooling, and a wear-resistant surface reinforced by a CrN / CrCN / CrC transition layer-Ta-C was obtained.

[0105] Comparative Example 1

[0106] The preparation method is the same as in Example 1, except that only the substrate is used.

[0107] Comparative Example 2

[0108] The preparation method is the same as in Example 1, except that the transition layer, nano-interdiffusion layer, and Ta-C coating are not provided.

[0109] Comparative Example 3

[0110] The preparation method is the same as in Example 1, except that the nano-interdiffusion layer and Ta-C coating are not provided.

[0111] Comparative Example 4

[0112] The preparation method is the same as in Example 1, except that no nano-interdiffusion layer is provided.

[0113] Comparative Example 5

[0114] The preparation method is the same as in Example 1, except that the nitriding layer, nano-interdiffusion layer and Ta-C coating are not provided.

[0115] Comparative Example 6

[0116] The preparation method is the same as in Example 1, except that the nitriding layer, transition layer, and nano-interdiffusion layer are not set.

[0117] Test methods and results:

[0118] 1. From Figure 2 As can be seen from the cross-sectional morphology and elemental composition of the wear-resistant surface prepared in Example 1, an elemental gradient transition is formed, which provides better support for the Ta-C coating.

[0119] 2. From Figure 3 As can be seen, this application has a nitriding layer, a transition layer, a nano-diffusion layer and a Ta-C coating on the substrate surface, which has higher hardness and elastic modulus.

[0120] 3. Figure 4 The scratch morphology of the wear-resistant surface prepared in Comparative Example 4 after scratch adhesion test is shown. The horizontal axis represents the applied load. During the scratching process with a loading load of 0-100N, cracks and damage appeared in the transition layer, and the coating adhesion was 21N.

[0121] 4. From Figure 5 and Figure 6It can be seen that the coating adhesion of Comparative Example 5 is 12 N, the coating adhesion of Example 1 is 24 N, and the adhesion between the Ta-C layer and the transition layer is doubled by forming a nano-interdiffusion layer between the Ta-C layer and the transition layer through ion bombardment, reducing the surface roughness of the transition layer, and improving the adhesion between the Ta-C layer and the transition layer.

[0122] 5、from Figure 7 and Figure 8 It can be seen that, compared with the substrate without strengthening treatment (Comparative Example 1), the wear-resistant surface of the substrate after ion nitriding-CrN / CrCN / CrC transition layer-nano-interdiffusion layer-Ta-C coating strengthening (Example 1) has a sp 3 The bond ratio reaches 81%, the friction performance is greatly improved, the friction coefficient is only 0.03 in the oil lubrication state when rubbing against an alumina ball, and the wear is close to zero under a load of 10 N.

[0123] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and embodiments having substantially the same configuration and playing the same role and effect as the technical idea within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, within the scope of the main idea of the present application, various modifications that can be thought of by those skilled in the art are applied to the embodiments, and other ways are constructed by combining part of the constituent elements in the embodiments, which are also included in the scope of the present application.

Claims

1. A wear surface, characterized in that, The wear-resistant surface comprises: a substrate comprising at least one of pure metal or alloy material; a nitrided layer on one side of the substrate; a transition layer on the side of the nitrided layer away from the substrate, the transition layer comprising CrN layer, CrCN layer and CrC layer arranged in sequence along the direction away from the substrate; a nanometer interdiffusion layer on the side of the transition layer away from the nitrided layer; a tetrahedral amorphous carbon layer on the side of the nanometer interdiffusion layer away from the transition layer.

2. The wear surface of claim 1, wherein, The thickness of the nitrided layer is 50 μm-300 μm; and / or, The thickness of the CrN layer is 200 nm-1000 nm; and / or, The thickness of the CrCN layer is 200 nm-1000 nm; and / or, The thickness of the CrC layer is 200 nm-1000 nm; and / or, The thickness of the nanometer interdiffusion layer is 2 nm-30 nm; and / or, The thickness of the tetrahedral amorphous carbon layer is 300 nm-1500 nm.

3. A wear surface according to claim 1 or 2, characterised in that, The nitrided layer comprises Fe3N, Fe4N and solid solution of nitrogen in α-Fe.

4. The wear surface of claim 1 or 2, wherein, The proportion of sp 3 The proportion of hybrid carbon atoms to the total number of carbon atoms is 70% to 90%.

5. The wear surface of claim 1 or 2, wherein, The hardness of the tetrahedral amorphous carbon layer is a, the hardness of the transition layer is b, the hardness of the nitrided layer is c, and the hardness of the substrate is d, a > b > c > d; wherein, a is 25 GPa-60 GPa; and / or, b is 15 GPa-30 GPa; and / or, c is 10 GPa-20 GPa; and / or, d is 4 GPa-10 GPa.

6. A method of making a wear surface according to any one of claims 1 to 5, characterised in that, The wear-resistant surface comprises: ion nitriding treatment is performed on a substrate to obtain a nitrided layer, the substrate comprising at least one of pure metal or alloy material; CrN layer, CrCN layer and CrC layer are sequentially deposited on the side of the nitrided layer away from the substrate by arc ion plating to obtain a transition layer; the transition layer is subjected to argon ion bombardment treatment to obtain a nanometer interdiffusion layer; a tetrahedral amorphous carbon layer is deposited on the side of the nanometer interdiffusion layer away from the transition layer by magnetic filter cathode arc deposition to obtain the wear-resistant surface.

7. The method of claim 6, wherein, The bias voltage of the arc ion plating is 50 V-300 V, the gas pressure is 1 Pa-2 Pa, and the temperature is 200 ℃-500 ℃; and / or, The bias voltage of the magnetic filter cathode arc deposition is 100 V-1500 V, and the temperature is 50 ℃-100 ℃.

8. The method according to claim 6 or 7, characterized in that, The argon ion bombardment treatment is performed for 30 min-60 min.

9. The method according to claim 6 or 7, characterized in that, The process parameters for depositing the tetrahedral amorphous carbon layer comprise: bias voltage of 100 V-1500 V and temperature of 50 ℃-100 ℃.

10. The wear-resistant surface of any one of claims 1-5 or the wear-resistant surface prepared by the method of any one of claims 6-9 for use in machining tools, automobiles, aerospace fields.

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