CN116657090B - Composite protective coating and preparation method thereof - Google Patents

Abstract

The application discloses a composite protective coating, which comprises an AlCrYN layer, a CrAlNx layer and a CrN layer which are sequentially arranged from top to bottom, wherein the AlCrYN layer comprises the following elements in percentage by atom: n:30-50%, al:25-40%, cr:20-30%, Y:0.2-7%, wherein the AlCrYN layer is of a cubic structure, has a preferred orientation of (200), a texture coefficient TC of 0.5-0.7, a grain size of 20-180nm, and a Y solid solution is formed in AlCrN crystal lattice. Compared with the prior art, the AlCrYN coating prepared by the technology has good uniformity, fine crystal grains in the coating and few crystal defects; has excellent friction coefficient, excellent hydrophobic property and reduced adhesion with aluminum liquid. The application can control the thickness of the coating by controlling the coating time, and finally, the application is simple and efficient, saves materials, accords with the sustainable development environment-friendly concept, has the potential of large-scale application in the field of aluminum liquid contact, and can realize huge social and economic benefits.

Description

Composite protective coating and preparation method thereof

Technical field

The invention belongs to the technical field of surface treatment, and specifically relates to a composite protective coating and a preparation method thereof.

Background technique

Aluminum and aluminum alloy components are widely used in aerospace, automotive, food, and electronic manufacturing fields due to their low density, good mechanical properties, excellent fatigue and corrosion resistance, and good electrical conductivity.

High-temperature aluminum liquid is highly corrosive. In the aluminum manufacturing process, materials such as molds and crucibles that are in direct contact with the aluminum liquid will be corroded, melted, adhered, and worn by the liquid aluminum during work. Damage to these materials will cause problems such as molten aluminum contamination, increased production costs, reduced product performance, and reduced production efficiency.

Currently, the surface properties of the substrate can be improved through surface strengthening technology, thereby improving the service performance of the substrate. Among surface strengthening technologies, PVD technology is widely used because it is green and environmentally friendly and causes less deformation of the substrate. The AlCrN coating prepared by arc ion plating is a type of ternary cemented carbide coating. It has the advantages of high hardness and strong bonding performance, and it is easy to form a high-temperature corrosion-resistant Al ₂ O ₃ phase on the surface at high temperatures, thereby slowing down Inward diffusion of O elements. However, the AlCrN coating has large internal stress, poor wear resistance, high friction coefficient, and is easy to adhere to molten aluminum at high temperatures, which limits its application.

Y is a chemically active rare earth element. TCRojas et al. successfully prepared AlCrYN coatings with different Al and Y contents by setting different Y target powers. They found that due to the reactive element effect, Y can inhibit Fe in the matrix and the coating. The Cr in the layer diffuses upward, making it easier for the coating to form a denser and more oxidation-resistant Al ₂ O ₃ layer at high temperatures instead of a relatively loose (Al, Cr) ₂ O ₃ layer.

At present, reports on AlCrYN coatings focus more on its high-temperature oxidation resistance, but less attention is paid to its mechanical protection and improvement of surface wettability, and the preparation method is to adjust the target power to adjust the coating content, which is cumbersome to prepare. , the coating cycle is long and the economic benefits are low. Moreover, the single-layer AlCrYN coating has poor bonding performance and is easily separated or peeled off from the substrate, causing the coating to fail.

Contents of the invention

The purpose of the present invention is to provide a composite protective coating with fine internal grains, few crystal defects, excellent friction coefficient, excellent hydrophobic properties, and reduced adhesion to molten aluminum.

In order to achieve the above object, the technical solution adopted by the present invention is: a composite protective coating, including an AlCrYN layer, a CrAlNx layer and a CrN layer arranged in sequence from top to bottom. In the AlCrYN layer, the atomic percentage content of each element is as follows: : N: 30-50%, Al: 25-40%, Cr: 20-30%, Y: 0.2-7%, the AlCrYN layer is a oriented cubic structure with (200) preferred orientation, and the texture coefficient TC is 0.5-0.7, the grain size is 20-180nm, and Y solid solution is formed in the AlCrN lattice.

The composite protective coating provided by the invention has a three-layer structure. Among them, the CrN transition layer is responsible for realizing strong bonding and high toughness functions, the CrAlNx gradient hard support layer realizes high hardness and impact resistance functions, and the AlCrYN coating realizes wear-resistant lubrication and hydrophobicity. Anti-aluminum liquid adhesion function. According to the Hall-Page effect, the smaller the grains, the higher the hardness of the coating. Through the solid solution of the Y element, the grain size of the AlCrYN layer becomes smaller, thereby increasing the hardness of the coating. At the same time, the solid solution of the Y element causes the AlCrYN layer to generate a Cr ₂ O ₃ phase and an Al ₂ O ₃ amorphous wrapped nanocrystalline structure during the friction process. The Cr ₂ O ₃ phase has a lubricating effect, and the Al ₂ O ₃ amorphous wrapped nanocrystalline structure The structure can prevent the flash temperature friction during the friction process from oxidizing the coating, thereby destroying the coating.

Preferably, the thickness ratio of the CrN layer to the CrAlNx layer is 1:(2-5), and the thickness ratio of the CrAlNx layer to the AlCrYN layer is (1-2):1. The thickness ratio of the three coating layers in the present invention has an important impact on the bonding, friction performance and wettability of the material. By adjusting the thickness ratio of the three layers, the surface energy of the coating can be effectively controlled, thereby effectively improving its hydrophobic performance. Among them, the thickness ratio of the CrN layer to the CrAlNx layer affects the bonding performance of the coating. The CrN layer, as a transition layer, can effectively bind to the Fe and Cr elements in the mold steel, and the CrAlN layer, as a hard support layer, can improve the hardness of the coating. , to prevent the coating from peeling off. By adjusting the thickness ratio of the two layers, the bonding, hardness, and toughness of the coating can be simultaneously improved. The thickness ratio of the CrAlNx layer to the AlCrYN layer affects the friction performance and wettability of the coating. The CrAlNx layer serves as a hard support layer. The increase in hardness can effectively improve the friction performance of the coating, and the AlCrYN layer can generate during the friction process. The Cr ₂ O ₃ phase with lubricating effect can also improve the friction performance of the coating, but the ratio of the AlCrYN layer to the CrAlNx layer should not be too high, otherwise the overall hardness of the coating will decrease, thus affecting the friction performance. Surface free energy is a key factor affecting the wettability of solid surfaces, and surface free energy is affected by composition, preferred orientation, and microstructure. By adjusting the thickness ratio of the CrAlNx layer to the AlCrYN layer, the CrAlNx layer does not completely generate a cubic structure. , but generates a mixed structure of cubic and tetragonal phases, which causes the preferred orientation of the AlCrYN layer to change from (111) to (200), affecting the change in coating wettability.

Preferably, the CrAlNx layer has a mixed structure of cubic and tetragonal phases, and the mass percentage of N element in the CrAlNx layer is 10-35%. The lower N element content makes the combination of Cr, Al and N in the CrAlNx layer insufficient, and the face-centered cubic structure cannot be completely generated, in which some tetragonal phases are generated.

Preferably, the thickness of the composite protective coating is 0.8-10 μm, the friction coefficient of the composite protective coating is 0.25-0.35, and the contact angle between the composite protective coating and water is 110-125°. Within the selection range, it not only ensures that the obtained composite coating has basic wear-resistant and hydrophobic properties, but also has the greatest economic benefits, which is beneficial to industrial production and application.

Another object of the present invention is to provide a method for preparing a composite protective coating, which specifically includes the following steps:

S1. In a vacuum atmosphere, place the substrate in a vacuum chamber, and use argon ions to etch the surface of the substrate;

S2. In a vacuum atmosphere, use a cathodic arc coating device, use Cr elemental target as the arc target, N ₂ as the reaction gas to provide N element, and deposit a CrN transition layer on the surface of the substrate;

S3. In a vacuum atmosphere, use a cathodic arc coating device, use a CrAl composite target as the arc target, _N2 as a reaction gas to provide N element, and deposit a CrAlNx layer on the surface of the CrN layer obtained in step S2;

S4. In a vacuum atmosphere, use a cathodic arc coating device, use CrAl composite target and CrY composite target as the arc target, _N2 as the reaction gas to provide N element, and deposit an AlCrYN layer on the surface of the CrAlNx layer obtained in step S3 to obtain a composite protective coating. .

Preferably, in step S1, the etching conditions are as follows: the working atmosphere is argon, the flow rate is 30-50 sccm, the vacuum degree during sputtering is 2.0×10 ^-5 -4.0×10 ^-5 Torr, and the substrate is preheated to 100-350℃, deposition bias voltage is -50V to -150V, linear anode ion source current is 0.2-0.3A, and substrate sputtering cleaning time is 30-90min. The present invention etches the substrate before depositing the CrN layer, which can effectively remove the loose layer and oxide scale on the surface of the substrate, which is equivalent to atomic-level micro shot peening, activates the surface of the substrate, improves the bonding strength of the film base, and also provides a basis for subsequent coating. Efficient pre-ionization is achieved.

Preferably, in step S2, the conditions for depositing the CrN transition layer are as follows: the working atmosphere is N ₂ , the incoming flow rate of N ₂ is 200-550 sccm, and the control air pressure is 30-50 mTorr. Excessive air pressure will cause the kinetic energy of the CrN layer Too low, but too low air pressure will result in insufficient plasma concentration and difficulty in film formation. The current is 60-90A, the substrate is preheated to 100-400°C, the deposition bias is -50V to -500V, the deposition time is 10-90min, and the target distance between the substrate and the Cr target is 10-15cm. By adjusting the appropriate target surface The spacing can make the coating have a faster film formation rate and better film formation quality, and reduce the large particles generated by the arc target during the deposition process.

Preferably, in step S3, the conditions for depositing the CrAlNx layer are as follows: the working atmosphere is N ₂ , the flow rate of N ₂ is 150-350 sccm, the control pressure is 35-85 mTorr, the current is 60-90 A, and the substrate is preheated to 100-400℃, deposition bias voltage is -50V to -500V. Too low a bias voltage will cause the coating deposition rate to be slow, but too high a bias voltage will make the compressive stress generated during the deposition process too large, resulting in The coating cracked, and the deposition time was 60-360 minutes. In the CrAl composite target, the element atomic percentage was Cr:Al=30:70. The element ratio was selected because the generated CrAlNx has a high Al element content, so that The hardness is extremely high. At the same time, the proportion of Al element exceeds this element ratio, and the harmful Hcp-AlN phase is easily generated, thereby reducing the hardness of CrAlNx. The target distance between the matrix and the CrAl composite target is 15-20cm.

Preferably, in step S4, the conditions for depositing the AlCrYN layer are as follows: the working atmosphere is N ₂ , the inflow flow of N ₂ is 300-650 sccm, the controlled air pressure is 35-85 mTorr, the substrate is preheated to 100-400°C, and the deposition The bias voltage is -50V to -500V, the current is 60-90A, and the deposition time is 60-360min. In the CrAl composite target, the element atomic percentage is Cr:Al=30:70. In the CrY composite target, the element atoms The percentage is Cr:Y=90:10. The AlCrYN layer generated at this content has optimal phase stability and is not prone to element segregation and decomposition. The target distance between the substrate and the CrY composite target and CrAl composite target is both 15-20cm.

Compared with the prior art, the present invention has the following advantages:

The composite protective coating prepared by the technology adopted in the present invention has good uniformity, fine internal grains and few crystal defects; it has an excellent friction coefficient and excellent hydrophobic properties, reducing adhesion to liquid aluminum. The present invention can control the coating thickness by controlling the coating time. Finally, the present invention is simple and efficient, saves materials, and conforms to the environmental protection concept of sustainable development. The coating has the potential for large-scale application in the field of aluminum liquid contact, and can realize huge social benefits. and economic benefits.

Description of the drawings

Figure 1 is an XRD structural diagram of the composite protective coating prepared in Example 1 of the present invention;

Figure 2 is a surface morphology diagram and a cross-sectional morphology diagram of the composite protective coating prepared in Example 1 of the present invention;

Figure 3 is a friction curve diagram of the composite protective coating prepared in Example 1 of the present invention and the composite coating prepared in Comparative Example 1;

Figure 4 is the contact angle between the composite coating prepared in Comparative Example 1 of the present invention and water;

Figure 5 is the contact angle between the composite protective coating prepared in Example 1 of the present invention and water.

Detailed ways

In order to make the above objects, features and advantages of the present invention more obvious and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

It should be understood that the terms used in the present invention are only used to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges in the present invention, it should be understood that every intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or value intermediate within a stated range and any other stated value or value intermediate within a stated range is also included within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded from the range.

It will be apparent to those skilled in the art that various modifications and changes can be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to the skilled person from the description of the invention. The specification and examples are intended to be illustrative only.

The embodiment of the present invention provides a composite protective coating, including an AlCrYN layer, a CrAlNx layer and a CrN layer arranged in sequence from top to bottom. In the AlCrYN layer, the atomic percentage content of each element is as follows: N: 30-50%, Al: 25-40%, Cr: 20-30%, Y: 0.2-7%, the AlCrYN layer has a cubic structure with (200) preferred orientation, the texture coefficient TC is 0.5-0.7, and the grain size is 20-180nm. Y solid solution is formed in the AlCrN lattice.

The composite protective coating provided by the invention has a three-layer structure. Among them, the CrN transition layer is responsible for realizing strong bonding and high toughness functions, the CrAlNx gradient hard support layer realizes high hardness and impact resistance functions, and the AlCrYN coating realizes wear-resistant lubrication and hydrophobicity. Anti-aluminum liquid adhesion function. According to the Hall-Page effect, the smaller the grains, the higher the hardness of the coating. Through the solid solution of the Y element, the grain size of the AlCrYN layer becomes smaller, thereby increasing the hardness of the coating. At the same time, the solid solution of the Y element causes the AlCrYN layer to generate a Cr ₂ O ₃ phase and an Al ₂ O ₃ amorphous wrapped nanocrystalline structure during the friction process. The Cr ₂ O ₃ phase has a lubricating effect, and the Al ₂ O ₃ amorphous wrapped nanocrystalline structure The structure can prevent the flash temperature friction during the friction process from oxidizing the coating, thereby destroying the coating.

In a specific implementation, the thickness ratio of the CrN layer to the CrAlNx layer is 1:(2-5), and the thickness ratio of the CrAlNx layer to the AlCrYN layer is (1-2):1. By adjusting the thickness ratio of the three layers, the surface energy of the coating can be effectively controlled, thereby effectively improving its hydrophobic performance.

In a specific implementation, the CrAlNx layer has a mixed structure of cubic and tetragonal phases, and the mass percentage of the N element in the CrAlNx layer is 10-35%.

In a specific embodiment, the thickness of the composite protective coating is 0.8-10 μm, the friction coefficient of the composite protective coating is 0.25-0.35, and the contact angle between the composite protective coating and water is 110-125°.

Another object of the present invention is to provide a method for preparing a composite protective coating, which specifically includes the following steps:

S1. Under a vacuum atmosphere, place the substrate in a vacuum chamber, and use argon ions to etch the surface of the substrate. The etching conditions are as follows: the working atmosphere is argon, the flow rate is 30-50 sccm, and the vacuum degree during sputtering is 2.0× 10 ^-5 -4.0×10 ^-5 Torr, the substrate is preheated to 100-350℃, the deposition bias is -50V to -150V, the linear anode ion source current is 0.2-0.3A, and the substrate sputtering cleaning time is 30-90min ;

S2. In a vacuum atmosphere, use a cathodic arc coating device, use Cr elemental target as the arc target, and _N2 as the reaction gas to provide N element, and deposit the CrN transition layer on the surface of the substrate. The conditions for depositing the CrN transition layer are as follows: The working atmosphere is N ₂ , the inlet flow rate of N ₂ is 200-550sccm, the control gas pressure is 30-50mTorr, the current is 60-90A, the substrate is preheated to 100-400℃, the deposition bias voltage is -50V to -500V, and the deposition time is 10- 90min, the target distance between the substrate and the Cr target is 10-15cm;

S3. In a vacuum atmosphere, use a cathodic arc coating device, use a CrAl composite target as the arc target, and _N2 as a reaction gas to provide N element. Deposit a CrAlNx layer on the surface of the CrN layer obtained in step S2. The conditions for depositing the CrAlNx layer are as follows: Work The atmosphere is N ₂ , the flow rate of N ₂ is 150-350 sccm, the control pressure is 35-85 mTorr, the current is 60-90A, the substrate is preheated to 100-400°C, the deposition bias is -50V to -500V, the deposition time is 60-360min. In the CrAl composite target, the element atomic percentage is Cr:Al=30:70, and the target distance between the matrix and the CrAl composite target is 15-20cm;

S4. In a vacuum atmosphere, use a cathodic arc coating device, use CrAl composite target and CrY composite target as the arc target, _N2 as the reaction gas to provide N element, and deposit an AlCrYN layer on the surface of the CrAlNx layer obtained in step S3 to obtain a composite protective coating. , the conditions for depositing the AlCrYN layer are as follows: the working atmosphere is N ₂ , the incoming flow rate of N ₂ is 300-650 sccm, the control air pressure is 35-85 mTorr, the substrate is preheated to 100-400°C, and the deposition bias voltage is -50V to -500V , the current is 60-90A, the deposition time is 60-360min, in the CrAl composite target, the atomic percentage of elements is Cr:Al=30:70, in the CrY composite target, the atomic percentage of elements is Cr:Y=90: 10. The target distance between the substrate and the CrY composite target and CrAl composite target is 15-20cm.

In a specific embodiment, the base body is selected from one of H13 steel, 8407 steel and SKD61 steel.

The technical effects of the present invention will be described below with reference to specific embodiments.

Example 1

In this embodiment, the substrate is H13 steel and the grade is 4Cr5MoSiV1. The preparation method of the composite protective coating on the surface of the substrate is as follows:

S1. Place the cleaned, degreased and dried substrate into the cavity, parallel to it in the vertical direction from the top edge of the CrAl target, and 12.53cm in the horizontal direction. Wait until the vacuum pressure in the cavity is below 3.0×10 ^-5 Torr. Pour 33.2 sccm of argon gas into the vacuum chamber, set the linear anode ion source current to 0.2 A, and the substrate bias voltage to -200 V. Use ionized argon ions to etch the 100°C substrate for 30 minutes;

S2. In 550sccm _N2 , the control gas valve is 50mTorr, the temperature is 200℃, a Cr element single target is installed on the arc source, as the Cr source, the target power is 1.0kw, the current is 70A, the deposition is 10min, and the substrate bias is -500V, during the process of depositing the coating, the substrate is rotated at a constant speed in the cavity to obtain a CrN transition layer;

S3. In 250sccm _N2 , the control gas valve is 35mTorr, the temperature is 200℃, a CrAl target is installed on the arc source, the target power is 1.0kw, the current is 60A, the deposition bias is -50V, deposition is 60min, and the deposition coating is During the layering process, the substrate is rotated at a constant speed in the cavity to obtain a CrAlNx layer;

S4. In 650sccm _N2 , the control gas valve is 80mTorr, the temperature is 200℃, CrAl target and CrY target are installed on the arc source, the target power is 1.0kw, the current is 60A, and the deposition is 60min. During the process of depositing the coating , causing the substrate to rotate at a constant speed in the cavity to obtain an AlCrYN layer.

Figure 1 is an XRD pattern of the composite protective coating produced in this embodiment. Figure 2 is a surface morphology diagram and cross-sectional morphology diagram of the composite protective coating produced in this embodiment. Figure 2 a is a diagram of this embodiment. The surface morphology of the composite protective coating prepared in this embodiment. b in Figure 2 is the cross-sectional morphology of the composite protective coating prepared in this embodiment. Figure 3 is the composite protective coating prepared in this embodiment and the comparative example. The friction curve of the composite coating prepared in 1. Figure 5 is the contact angle between the composite protective coating prepared in this embodiment and water; it can be seen from Figures 1, 2, 3, 5 and related test results. , the total thickness of the composite protective coating in this embodiment is 3.83um, the thickness ratio is approximately CrN:CrAlNx:AlCrYN=1:3:3, the Cr element content of the innermost layer of the coating is 51.64at.%, and the N element content is 48.36 at.%; the Al element content in the middle layer is 19.63at.%, the Cr element content is 39.05at.%, and the N element content is 41.32at.%; the Al element content in the outermost layer is 38.00at.%, and the Cr element content is 20.05 at.%, the N element content is 41.32at.%; the Y element content is 0.63at.%. The bonding strength between the composite protective coating and the substrate is 85.9N. The friction coefficient of the composite protective coating at room temperature is 0.27. The CrAlNx layer of the composite protective coating has a mixed structure of cubic and tetragonal phases. The texture of the composite protective coating (200) The coefficient is 0.69, and the contact angle between the composite protective coating and water is 125°.

Example 2

In this embodiment, the substrate is H13 steel and the grade is 4Cr5MoSiV1. The preparation method of the composite protective coating on the surface of the substrate is as follows:

S1. Put the cleaned, degreased and dried substrate into the cavity. Its vertical height is 3.5cm lower than the top edge of the CrAl target, and the horizontal distance is 12.53cm. Wait until the vacuum pressure in the cavity reaches 3.0×10 ^- Below ⁵ Torr, pass 33.2 sccm argon gas into the vacuum chamber, set the linear anode ion source current to 0.2A, and the substrate bias voltage to -200V. Use ionized argon ions to etch the 200°C substrate for 30 minutes;

S2. In 550sccm _N2 , the control gas valve is 50mTorr, the temperature is 200℃, a Cr element single target is installed on the arc source, as the Cr source, the target power is 1.0kw, the current is 70A, the deposition is 10min, and the substrate bias is -150V, during the process of depositing the coating, the substrate is rotated at a constant speed in the cavity to obtain a CrN transition layer;

S3. In 250sccm N ₂ , the control gas valve is 35mTorr, the temperature is 200°C, a CrAl target is installed on the arc source, the target power is 1.0kw, the current is 60A, and the deposition is 60min. During the process of depositing the coating, all The substrate rotates at a constant speed in the cavity to obtain a CrAlNx layer;

S4. In 650sccm _N2 , the control gas valve is 80mTorr, the temperature is 200℃, CrAl target and CrY target are installed on the arc source, the target power is 1.0kw, the current is 60A, the deposition is 60min, and the deposition bias is -500V. During the deposition of the coating, the substrate is rotated at a constant speed in the cavity to obtain an AlCrYN layer.

After testing, the total thickness of the composite protective coating in this example is 3.56 um, the thickness ratio is approximately CrN:CrAlNx:AlCrYN=1:3:3, and the Cr element content of the innermost layer of the composite protective coating is 54.92at.%. The N element content is 45.08at.%; the Al element content in the middle layer is 18.04at.%, the Cr element content is 38.05at.%, and the N element content is 43.91at.%; the Al element content in the outermost layer is 36.05at.%. The Cr element content is 17.08at.%, the N element content is 40.74at.%; the Y element content is 6.13at.%. The bonding strength between the composite protective coating and the substrate is 71.6N. The friction coefficient of the composite protective coating at room temperature is 0.39. The CrAlNx layer of the composite protective coating has a mixed structure of cubic and tetragonal phases. The texture of the composite protective coating (200) The coefficient is 0.57, and the contact angle between the composite protective coating and water is 118°.

Example 3

In this embodiment, the substrate is 8407 steel, and the preparation method of the composite protective coating on the surface of the substrate is as follows:

S1. Place the cleaned, degreased and dried substrate into the cavity, parallel to it in the vertical direction from the top edge of the CrAl target, and 12.53cm in the horizontal direction. Wait until the vacuum pressure in the cavity is below 3.0×10 ^-5 Torr. Pour 33.2 sccm of argon gas into the vacuum chamber, set the linear anode ion source current to 0.2 A, and the substrate bias voltage to -200 V. Use ionized argon ions to etch the 350°C substrate for 30 minutes;

S2. In 550sccm _N2 , the control gas valve is 50mTorr, the temperature is 200℃, a Cr element single target is installed on the arc source, as the Cr source, the target power is 1.0kw, the current is 70A, the deposition is 10min, and the substrate bias is -200V, during the process of depositing the coating, the substrate is rotated at a constant speed in the cavity to obtain a CrN transition layer;

S3. In 250sccm _N2 , the control gas valve is 35mTorr, the temperature is 200℃, a CrAl target is installed on the arc source, the target power is 1.0kw, the deposition bias is -250V, the current is 60A, the deposition is 90min, and the deposition coating During the layering process, the substrate is rotated at a uniform speed in the cavity to obtain a CrAlNx layer;

S4. In 650sccm _N2 , the control gas valve is 80mTorr, the temperature is 200℃, CrAl target and CrY target are installed on the arc source, the target power is 1.0kw, the current is 60A, and the deposition is 90min. During the process of depositing the coating , causing the substrate to rotate at a constant speed in the cavity to obtain an AlCrYN layer.

After testing, the total thickness of the composite protective coating in this embodiment is 5.31um, the thickness ratio is approximately CrN:CrAlNx:AlCrYN=1:5:5, and the Cr element content of the innermost layer of the composite protective coating is 51.73at.%, N The element content is 48.27at.%; the Al element content in the middle layer is 19.83at.%, the Cr element content is 32.91at.%, and the N element content is 47.26at.%; the Al element content in the outermost layer is 34.97at.%, Cr The element content is 20.62at.%, the N element content is 43.62at.%; the Y element content is 0.79at.%. The bonding strength between the composite protective coating and the substrate is 82.5N. The friction coefficient of the composite protective coating at room temperature is 0.29. The CrAlNx layer of the composite protective coating has a mixed structure of cubic and tetragonal phases. The texture of the composite protective coating (200) The coefficient is 0.52, and the contact angle between the composite protective coating and water is 110°.

Example 4

In this embodiment, the substrate is H13 steel and the grade is 4Cr5MoSiV1. The preparation method of the composite protective coating on the surface of the substrate is as follows:

S1. Place the cleaned, degreased and dried substrate into the cavity, parallel to it in the vertical direction from the top edge of the CrAl target, and 12.53cm in the horizontal direction. Wait until the vacuum pressure in the cavity is below 3.0×10 ^-5 Torr. Pour 33.2 sccm of argon gas into the vacuum chamber, set the linear anode ion source current to 0.2 A, and the substrate bias voltage to -200 V. Use ionized argon ions to etch the 200°C substrate for 30 minutes;

S2. In 550sccm _N2 , control the gas valve 50mTorr, the temperature is 200℃, install a Cr element single target material on the arc source, as the Cr source, the target power is 1.0kw, the current is 70A, the deposition is 10min, and the substrate bias is -50V, during the process of depositing the coating, the substrate is rotated at a constant speed in the cavity to obtain the CrN transition layer;

S3. In 250sccm _N2 , the control gas valve is 35mTorr, the temperature is 200℃, a CrAl target is installed on the arc source, the target power is 1.0kw, the current is 60A, the deposition bias is -50V, the deposition is 120min, and the deposition coating During the layering process, the substrate is rotated at a uniform speed in the cavity to obtain a CrAlNx layer;

S4. In 650sccm _N2 , the control gas valve is 80mTorr, the temperature is 200℃, CrAl target and CrY target are installed on the arc source, the target power is 1.0kw, the current is 60A, and the deposition is 60min. During the process of depositing the coating , causing the substrate to rotate at a constant speed in the cavity to obtain an AlCrYN layer.

After testing, the total thickness of the composite protective coating produced in this example is 4.97um, the thickness ratio is approximately CrN:CrAlNx:AlCrYN=1:4:2, and the Cr element content of the innermost layer of the composite protective coating is 50.25at. %, the N element content is 49.75at.%; the Al element content in the middle layer is 19.66at.%, the Cr element content is 30.71at.%, the N element content is 49.63at.%; the Al element content in the outermost layer is 34.63at.%. %, the Cr element content is 20.85at.%, the N element content is 43.74at.%; the Y element content is 0.78at.%. The bonding strength between the composite protective coating and the substrate is 75.4N. The friction coefficient of the composite protective coating at room temperature is 0.34. The CrAlNx layer of the composite protective coating has a mixed structure of cubic and tetragonal phases. The texture of the composite protective coating (200) The coefficient is 0.56, and the contact angle between the composite protective coating and water is 110°.

Comparative example 1

In this comparative example, the substrate is H13 steel and the grade is 4Cr5MoSiV1. The specific preparation process of the composite coating in this comparative example is as follows:

S1. Place the cleaned, degreased and dried substrate into the chamber. When the vacuum pressure in the chamber is below 3.0×10 ^-5 Torr, introduce 33.2 sccm argon gas into the vacuum chamber and set the linear anode ion source current to 0.2A, the substrate bias voltage is -200V, and the substrate is etched with ionized argon ions for 30 minutes;

S2. In 550sccm _N2 , the control gas valve is 50mTorr, the temperature is 200℃, a Cr element single target is installed on the arc source, as the Cr source, the target power is 1.0kw, the current is 70A, the deposition is 10min, and the deposition coating During the layering process, the substrate is allowed to rotate at a constant speed in the cavity to obtain a CrN transition layer;

S3. In 650sccm _N2 , the control gas valve is 80mTorr, the temperature is 200℃, a CrAl target is installed on the arc source, the target power is 1.0kw, the current is 60A, and the deposition is 120min. During the process of depositing the coating, all The substrate rotates at a constant speed in the cavity to obtain an AlCrN layer.

Figure 3 is a friction curve diagram of the composite protective coating prepared in Example 1 of the present invention and the composite coating prepared in Comparative Example 1. Figure 4 is the contact angle between the composite coating prepared in this comparative example and water; from Figure 3. From Figure 4 and related test results, it can be concluded that the total thickness of the composite coating in this comparative example is 3.14um, the Al element content in the composite coating is 14.80at.%, the Cr element content is 39.37at.%, and the N element The content is 45.83at.%; the bonding strength between the composite coating and the substrate is 68.9N, the friction coefficient of the composite coating at room temperature is 0.45, the texture coefficient of the composite coating (111) is 0.86, and the contact between the composite coating and water The angle is 70°. It can be seen from the results of Implementation 1 and this comparative example that the AlCrYN coating plays an indispensable role in the three-layer composite coating of the present invention and directly affects the physical and mechanical properties of the composite coating.

Comparative example 2

In this comparative example, the substrate is H13 steel and the grade is 4Cr5MoSiV1. The specific preparation process of the composite coating in this comparative example is as follows:

S1. Put the cleaned, degreased and dried substrate into the cavity. The vertical height difference from the top edge of the CrAl target is 5.5cm and the horizontal distance is 12.53cm. Wait until the vacuum pressure in the cavity reaches 3.0×10 ^- Below ⁵ Torr, pass 33.2 sccm argon gas into the vacuum chamber, set the linear anode ion source current to 0.2A, the substrate bias voltage to -200V, and use ionized argon ions to etch the substrate for 30 minutes;

S2. In 550sccm _N2 , the control gas valve is 50mTorr, the temperature is 200℃, a Cr element single target is installed on the arc source, as the Cr source, the target power is 1.0kw, the current is 70A, the deposition is 10min, and the deposition coating During the layering process, the substrate is allowed to rotate at a constant speed in the cavity to obtain a CrN transition layer;

S3. In 250sccm N ₂ , the control gas valve is 35mTorr, the temperature is 200°C, a CrAl target is installed on the arc source, the target power is 1.0kw, the current is 60A, and the deposition is 60min. During the process of depositing the coating, all The substrate rotates at a constant speed in the cavity to obtain a CrAlNx layer;

S4. In 650sccm _N2 , the control gas valve is 80mTorr, the temperature is 200℃, CrAl target and CrY target are installed on the arc source, the target power is 1.0kw, the current is 60A, and the deposition is 60min. During the process of depositing the coating , causing the substrate to rotate at a constant speed in the cavity to obtain an AlCrYN layer.

After testing, the total thickness of the composite coating prepared in this comparative example is 3.76um, the thickness ratio is approximately CrN:CrAlNx:AlCrYN=1:3:3, and the Cr element content of the innermost layer of the coating is 51.55at.%, N The element content is 48.45at.%; the Al element content in the middle layer is 19.03at.%, the Cr element content is 39.02at.%, and the N element content is 41.95at.%; the Al element content in the outermost layer is 35.65at.%, Cr The element content is 18.19at.%, the N element content is 37.62at.%; the Y element content is 8.54at.%. The bonding strength between the composite coating and the substrate is 67.7N. The friction coefficient of the composite coating at room temperature is 0.40. The CrAlNx layer of the composite coating has a mixed structure of cubic and tetragonal phases. The texture coefficient of the composite coating (200) The texture coefficient of the composite coating (111) is 0.55, and the contact angle between the composite coating and water is 87°. It can be seen from the results of Example 1 and this comparative example that the doping amount of Y element has an impact on the performance of the composite coating. When the Y element content is not within the range described in the present invention, the mechanical properties of the obtained composite coating are The hydrophobic properties are reduced.

Comparative example 3

In this comparative example, the substrate is H13 steel and the grade is 4Cr5MoSiV1. The specific preparation process of the composite coating in this comparative example is as follows:

S1. Put the cleaned, degreased and dried substrate into the cavity. The vertical height difference from the top edge of the CrAl target is 5.5cm and the horizontal distance is 12.53cm. Wait until the vacuum pressure in the cavity reaches 3.0×10 ^- Below ⁵ Torr, pass 33.2 sccm argon gas into the vacuum chamber, set the linear anode ion source current to 0.2A, the substrate bias voltage to -200V, and use ionized argon ions to etch the substrate for 30 minutes;

S2. In 550sccm _N2 , the control gas valve is 50mTorr, the temperature is 200℃, a Cr element single target is installed on the arc source, as the Cr source, the target power is 1.0kw, the current is 70A, the deposition is 5min, and the deposition coating During the layering process, the substrate is allowed to rotate at a constant speed in the cavity to obtain a CrN transition layer;

S3. In 250sccm _N2 , the control gas valve is 35mTorr, the temperature is 200℃, a CrAl target is installed on the arc source, the target power is 1.0kw, the current is 60A, and the deposition is 120min. During the process of depositing the coating, all The substrate rotates at a constant speed in the cavity to obtain a CrAlNx layer;

S4. In 650sccm _N2 , the control gas valve is 80mTorr, the temperature is 200℃, CrAl target and CrY target are installed on the arc source, the target power is 1.0kw, the current is 60A, and the deposition is 60min. During the process of depositing the coating , causing the substrate to rotate at a constant speed in the cavity to obtain an AlCrYN layer.

After testing, the total thickness of the composite coating in this comparative example is 4.87um, the thickness ratio is approximately CrN:CrAlNx:AlCrYN=1:8:4, the Cr element content of the innermost layer of the composite coating is 50.15at.%, and the N element The content is 49.85at.%; the Al element content in the middle layer is 20.85at.%, the Cr element content is 33.22at.%, and the N element content is 45.93at.%; the Al element content in the outermost layer is 37.65at.%, and the Cr element content is 37.65at.%. The content is 17.00at.%, the N element content is 40.62at.%; the Y element content is 4.73at.%. The bonding strength between the composite coating and the substrate is 62.5N. The friction coefficient of the composite coating at room temperature is 0.43. The CrAlNx layer of the composite coating has a mixed structure of cubic and tetragonal phases. The texture coefficient of the composite coating (111) is 0.67. The contact angle of the composite coating with water is 80°. It can be seen from the results of Example 1 and this comparative example that the thickness of the three-layer coating directly affects the performance of the composite coating finally produced by the present invention. In this comparative example, CrN:CrAlNx:AlCrYN=1:8:4, we get The bonding strength of the composite coating decreases while the hydrophobic performance also decreases.

To sum up, the present invention adopts CrN coating, CrAlNx coating and AlCrYN coating, and rationally configures the Y element doping content and the thickness of the three-layer coating, so that the obtained composite protective coating has an excellent friction coefficient. And hydrophobic properties, as well as the bonding strength with the matrix.

Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims (8)

1. The composite protective coating is characterized by comprising an AlCrYN layer, a CrAlNx layer and a CrN layer which are sequentially arranged from top to bottom, wherein the AlCrYN layer comprises the following elements in percentage by atom: n:30-50%, al:25-40%, cr:20-30%, Y:0.2-7%, wherein the AlCrYN layer is of a face-centered cubic structure, has a preferred orientation of (200), a texture coefficient TC is 0.5-0.7, a grain size is 20-180nm, Y solid solution is formed in an AlCrN lattice, the thickness ratio of the CrN layer to the CrAlNx layer is 1 (2-5), and the thickness ratio of the CrAlNx layer to the AlCrYN layer is (1-2): 1.

2. The composite protective coating according to claim 1, wherein the CrAlNx layer has a cubic and tetragonal phase mixed structure, and the mass percentage of N element in the CrAlNx layer is 10-35%.

3. The composite protective coating of claim 1, wherein the composite protective coating has a thickness of 0.8-10 μm, a coefficient of friction of 0.25-0.35, and a contact angle of 110-125 ° with water.

4. A method for preparing a composite protective coating according to any one of claims 1 to 3, comprising the steps of:

s1, placing a substrate in a vacuum chamber under a vacuum atmosphere, and etching the surface of the substrate by utilizing argon ions;

s2, under the vacuum atmosphere, using a cathodic arc coating device, taking a Cr simple substance target as an arc target, and N ₂ Providing N element as reaction gas, and depositing a CrN transition layer on the surface of the substrate;

s3, under vacuum atmosphere, using a cathode arc coating device, taking a CrAl composite target as an arc target, and N ₂ Providing N element as a reaction gas, and depositing a CrAlNx layer on the surface of the CrN layer obtained in the step S2;

s4, under vacuum atmosphere, using a cathode arc coating device, taking a CrAl composite target and a CrY composite target as arc targets, and N ₂ And (3) providing N element as reaction gas, and depositing an AlCrYN layer on the surface of the CrAlNx layer obtained in the step (S3) to obtain the composite protective coating.

5. As in claim 4The preparation method of the composite protective coating is characterized in that in the step S1, etching conditions are as follows: the working atmosphere is argon, the flow is 30-50sccm, and the vacuum degree is 2.0X10 during sputtering ^-5 -4.0×10 ^-5 The Torr is used for preheating the substrate to 100-350 ℃, the deposition bias voltage is-50V to-150V, the linear anode ion source current is 0.2-0.3A, and the sputtering cleaning time of the substrate is 30-90min.

6. The method for preparing a composite protective coating according to claim 4, wherein in the step S2, the conditions for depositing the CrN transition layer are as follows: the working atmosphere is N ₂ ，N ₂ The flow rate of the substrate is 200-550sccm, the control air pressure is 30-50mTorr, the current is 60-90A, the substrate is preheated to 100-400 ℃, the deposition bias voltage is-50V to-500V, the deposition time is 30-90min, and the target distance between the substrate and the Cr target is 10-15cm.

7. The method for preparing a composite protective coating according to claim 4, wherein in the step S3, the conditions for depositing the CrAlNx layer are as follows: the working atmosphere is N ₂ ，N ₂ The method comprises the steps of (1) controlling the inlet flow of 150-350sccm, controlling the air pressure to 40-85mTorr, controlling the current to 60-90A, preheating a substrate to 100-400 ℃, depositing the substrate at a bias voltage of-50V to-500V and depositing the substrate for 60-360min, wherein the atomic percentage of elements in the CrAl composite target is Cr: al=30:70, and the target spacing between the substrate and the CrAl composite target is 15-20cm.

8. The method for preparing a composite protective coating according to claim 4, wherein in the step S4, the conditions for depositing the AlCrYN layer are as follows: the working atmosphere is N ₂ ，N ₂ The method comprises the steps of (1) controlling the inlet flow of 300-650sccm, controlling the air pressure to be 40-85mTorr, preheating a substrate to 100-400 ℃, depositing the substrate with a bias voltage of-50V to-500V, and depositing the substrate with a current of 60-90A for 60-360min, wherein the atomic percentage of elements in the CrAl composite target is Cr: al=30:70, the atomic percentage of elements in the CrY composite target is Cr: Y=90:10, and the target spacing between the substrate and the CrY composite target and between the substrate and the target spacing between the substrate and the CrAl composite target are 15-20cm.