An AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating with adjustable composition for high-pressure die-casting molds and its preparation method

Abstract

The present invention discloses an AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating with adjustable composition for high-pressure die-casting molds and a preparation method thereof, belonging to the technical field of thin film materials. The present invention combines the excellent mechanical properties of high-entropy alloy nitrides with the specific high-temperature properties, oxidation resistance and wear resistance of high-entropy alloy oxides. The prepared coating not only has the excellent mechanical properties of high-entropy alloy nitrides, but also has more excellent oxidation resistance, high-temperature stability and wear resistance, which can ensure the long-term stable operation of high-pressure die-casting molds under high-temperature conditions. The present invention makes full use of the nano-multilayer composite and gradient composite coating technologies to form a gradual change in structure and composition, reduce the mismatch degree of lattice constants and thermal expansion coefficients between the coating and the substrate, and has good adhesion. The present invention provides a preparation method for this coating, which has good adhesion and a high deposition rate, improving the performance and production efficiency of the coating.

Description

Technical Field

[0001] The present invention relates to the technical field of thin film materials, and particularly to an AlCrNbSiTiON high-entropy alloy nitride nanocomposite coating with adjustable composition for high-pressure die casting molds and a preparation method thereof. Background Art

[0002] The demand in the global manufacturing industry is huge and continuously growing. High-pressure die casting (HPDC) is one of the most commonly used technologies in the light metal casting industrial process because of its excellent performance in high-efficiency mass production. High-pressure die casting has a wide range of applications in various fields such as the automotive industry, aerospace, and precision manufacturing. Despite the progress in surface engineering and coating processing, high-pressure die casting molds still suffer from serious degradation problems caused by welding, wear, erosive wear, and thermal fatigue due to various mechanical, chemical interactions, and thermal cycles. It is crucial to provide effective protection for high-pressure die casting molds by selecting appropriate coating materials and preparation conditions to meet the requirements of high-pressure die casting, improve the high-pressure die casting efficiency, extend the service life of high-pressure die casting molds, and reduce production costs. Currently, coating technology is the most common and effective technology for protecting high-pressure die casting molds and further extending their service life.

[0003] In the past three decades, the focus of hard coating materials has shifted to improving the mechanical properties, thermal stability, and oxidation resistance of thin films so that they can withstand harsh operating conditions. The solution to this problem lies in combining several elements to form ternary or multi-element material systems such as TiAlN, TiSiN, CrAlO, CrAlN, TiAlSiN, etc. In recent years, many surface modifications have provided ideal and reliable methods, especially PVD hard coatings combined with plasma nitriding. PVD coatings can act as a physical barrier to prevent welding, erosion, and wear. And due to the diffusion of nitrogen in the plasma nitriding pretreatment, an appropriate stress and hardness gradient is formed between the coating and the substrate, thereby improving the fatigue strength and load-bearing capacity of the substrate. The duplex treatment of adding a plasma nitriding layer under the PVD hard coating can better support the coating, thereby further improving the performance and the service life of high-pressure die casting molds. In recent decades, oxynitride coatings have received important research interest due to their excellent oxidation resistance, thermal stability, and tunability for various high-temperature applications. However, traditional nitride coatings and oxynitride protective coatings cannot fully meet the requirements of high mechanical properties, high hardness, high wear resistance, and good stability for precision and high-efficiency manufacturing. Therefore, it is crucial to develop high-performance coating materials for high-pressure die casting molds.

[0004] High entropy alloys (HEAs) are a class of multi-principal element alloys composed of five or more metal elements. They usually have a high configurational entropy and are prone to form solid solutions with a single BCC, FCC, or HCP structure. Four special effects, namely the high entropy effect, lattice distortion effect, sluggish diffusion effect, and cocktail effect, endow HEAs with high hardness, high strength, wear resistance, oxidation resistance, and corrosion resistance. With the increasing demand for high-hardness, high-strength, and high-wear-resistant coatings, high entropy alloy nitrides based on HEAs have attracted extensive attention. High entropy alloy nitride coatings have gained great importance in various applications due to their special physical and chemical properties.

[0005] The synthesis of high entropy alloy nitrides is considered a novel method for preparing multifunctional thin films. It is worth noting that their properties depend to a large extent on the deposition conditions of the coating and the nitrogen-oxygen chemical composition ratio. The deposition conditions of the coating and the nitrogen-oxygen chemical composition ratio not only affect the crystal growth but also the ratio of metal to ionic bonds, thus further changing the properties of the coating. Summary of the Invention

[0006] In view of the above-mentioned defects of the prior art, in the first aspect of the present invention, there is provided an AlCrNbSiTiON high entropy alloy nitride nanocomposite coating with excellent wear resistance and high-temperature stability. The AlCrNbSiTiON high entropy alloy nitride nanocomposite coating has a gradient structure and includes a bonding layer, a transition layer, a support layer, and a temperature-resistant wear-resistant layer, wherein the bonding layer is the contact layer with the substrate; in terms of the composition of each layer, the bonding layer is a Cr bonding layer, the transition layer is a CrN transition layer, the support layer is a CrN / AlCrNbSiTiN support layer, and the temperature-resistant wear-resistant layer is an AlCrNbSiTiON temperature-resistant wear-resistant layer.

[0007] The main idea of the present invention is to combine the excellent mechanical properties of high entropy alloy nitrides with the specific high-temperature properties, oxidation resistance, and wear resistance of high entropy alloy oxides, so that it not only has the excellent mechanical properties of nitrides but also has more excellent oxidation resistance, high-temperature stability, and wear resistance of oxides.

[0008] To avoid the coating peeling off at high temperatures due to the large difference in the thermal expansion coefficients between the coating and the substrate, the coating design adopts a gradient layer structure and a nano-multilayer structure to improve the coating adhesion and toughness. The coating is designed according to the cocktail effect. Strong nitride-forming elements endow the coating with high hardness. The addition of Al is beneficial to improving the oxidation resistance of the material, while Nb and Si can enhance the toughness and wear resistance of the material. Cubic transition metal (TM) nitrides have high hardness, oxidation resistance, corrosion resistance, and phase stability, and can withstand harsh working conditions under high temperatures and corrosive chemical environments. Among TM nitrides, CrN coatings and AlN are the best candidate materials to meet this requirement because CrN coatings and AlN coatings form passivating Cr2O3 layers and Al2O3 layers, which contain interstitial nitrogen and can prevent oxygen from diffusing through the coating at high temperatures. In coatings containing both Cr and Al, the template effect of Cr2O3 accelerates the formation of Al2O3 at lower temperatures, thereby further enhancing the thermal stability and wear resistance of the coating at high temperatures. Due to the simultaneous presence of non-metallic elements O and N in the structure, the presence of N can be excited by introducing covalent bonds, and the covalent bonds are close to the ionic bonds contributed by O in the structure. This transforms the structure of the compound from a pure ionic bond nature to a combination of ionic and covalent bonds, namely an ionic-covalent bond structure. Compared with most oxide ceramics, compounds with this structure are tougher (i.e., less brittle).

[0009] Preferably, the CrN / AlCrNbSiTiN support layer is composed of a CrN single layer and an AlCrNbSiTiN single layer compounded in a periodic alternating form.

[0010] More preferably, the thickness of the Cr bonding layer is 10 - 100 nm, the thickness of the CrN transition layer is 200 - 800 nm, and the thickness of the CrN / AlCrNbSiTiN support layer is 400 - 1500 nm, wherein the thickness of the CrN single layer is 10 - 30 nm, the thickness of the AlCrNbSiTiN single layer is 5 - 20 nm, and the thickness of a single-period coating obtained by compounding the CrN single layer and the AlCrNbSiTiN single layer is 15 - 50 nm.

[0011] Preferably, in the AlCrNbSiTiON temperature- and wear-resistant layer, the molar ratio relationship between O and N satisfies 1 / 20 ≤ O / N ≤ 20 / 1.

[0012] In the second aspect of the present invention, a preparation method for an AlCrNbSiTiON high-entropy alloy nitride oxide nano-composite coating with simple process, controllable parameters, and high production efficiency is provided. The arc ion plating process is adopted, and it includes the following steps:

[0013] (1) The matrix material of the high-pressure die-casting mold is etched by plasma to remove surface impurities and activate the surface, obtaining an activated matrix material of the high-pressure die-casting mold;

[0014] (2) Under an argon atmosphere, a Cr bonding layer is formed by deposition on the surface of the activated high-pressure die-casting mold matrix material;

[0015] (3) Under a nitrogen atmosphere, a CrN transition layer is formed by deposition on the surface of the Cr bonding layer;

[0016] (4) Under a nitrogen atmosphere, CrN monolayers and AlCrNbSiTiN monolayers are alternately deposited on the surface of the CrN transition layer in a cycle to form a CrN / AlCrNbSiTiN support layer;

[0017] (5) Under an oxygen and nitrogen atmosphere, an AlCrNbSiTiON temperature- and wear-resistant layer is formed by deposition on the surface of the CrN / AlCrNbSiTiN support layer, completing the preparation of the AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating.

[0018] In physical vapor deposition (PVD) processes, coatings are usually deposited at low temperatures that are 0.2 to 0.3 times the melting point. This indicates that the synthesis of the thin film is far from thermodynamic equilibrium, and it also shows that the PVD thin film technology can form non-equilibrium solid structures and adjust their properties. The AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating deposited by PVD is a protective coating for high-pressure die-casting molds with excellent comprehensive properties. This process successfully synthesizes an AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating with adjustable composition to meet the required properties for high-pressure die-casting mold applications.

[0019] Preferably, during the preparation of the AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating, the ambient temperature is maintained at 300 to 500 °C.

[0020] Preferably, in step (1), the pulse duty cycle of the arc power supply of the Cr target used for plasma etching is 10% to 80%, and the bias voltage is -50 to -150 V.

[0021] Preferably, in step (2), the deposition uses a Cr target, the ambient pressure during deposition is 0.1 to 1 Pa, the deposition bias voltage is 50 to 150 V, and the pulse duty cycle of the arc power supply of the Cr target is 10% to 80%.

[0022] Preferably, in step (3), the deposition uses a Cr target, the ambient pressure during deposition is 1 to 3 Pa, the deposition bias voltage is 50 to 150 V, and the pulse duty cycle of the arc power supply of the Cr target is 10% to 80%.

[0023] Preferably, in the step (4), Cr target and AlCrNbSiTi target are used for deposition to form a CrN single layer and an AlCrNbSiTiN single layer respectively. The ambient air pressure during deposition is 2-5 Pa, the deposition bias voltage of the Cr target is 50-150 V, and the pulse duty cycle of the arc power supply of the Cr target is 10%-80%; the deposition bias voltage of the AlCrNbSiTi target is 50-250 V, and the pulse duty cycle of the arc power supply of the AlCrNbSiTi target is 20%-80%.

[0024] Preferably, in the step (5), the AlCrNbSiTi target is used for deposition. The ambient air pressure during deposition is 2-5 Pa, the oxygen flow rate is 10-500 sccm, the deposition bias voltage is 50-250 V, the pulse duty cycle of the arc power supply of the AlCrNbSiTi target is 20%-80%, and the deposition time is 30-120 min.

[0025] Oxygen doping can regulate the structure and properties of the coating. By changing the oxygen flow rate, the transformation from nitride to oxynitride and then to oxide can be achieved. Oxygen doping leads to significant changes in the electronic structure and physical properties within the coating, and stress relaxation occurs in the coating. The deposition conditions of the coating and the chemical composition ratio of nitrogen and oxygen not only affect the crystal growth but also the ratio of metal to ionic bonds, thereby further changing the properties of the coating. Taking AlCrNbSiTiO x N 1-x to represent the composition (x represents the atomic number ratio), for the high-entropy alloy oxynitride nanocomposite coating with an oxygen content x≤0.6, the coating growth mode is columnar crystal growth, presenting a cubic lattice (FCC) structure, and the columnar structure grows well. The incorporation of oxygen into the nitride lattice results in a decrease in the cubic lattice parameter, forming a substituted AlCrNbSiTiO containing metal vacancies x N 1-xSolid solution. When the oxygen content is 0.6 < x ≤ 0.97, a coating with a diffuse columnar structure and a high metal vacancy value is formed, presenting a cubic lattice (FCC) structure. The coating with an oxygen content of x ≥ 0.97 is composed of a spinel structure and a solid solution of α-AlCrNbSiTiO with a fine columnar structure. The nitrides in the range of 0.6 < x ≤ 0.97 are metastable and transform into a biphasic composite of cubic nitrides and an oxidized spinel structure after the temperature reaches 1100 °C. This behavior is attributed to the sufficient amount of oxygen present in the coating, which enables the local formation of a spinel structure during the annealing process. All nitride coatings exhibit a low wear rate, which, together with their chemical inertness, qualifies them for use as die coatings under harsh conditions. This process regulates the structure and properties of the coating by introducing a mixed gas of N2 and O2, adjusting the O2 flow rate and N2 flow rate, changing the coating composition, controlling the generation of fewer and denser arcs on the target surface, and reducing the extension of the arcs on the target surface, thereby generating high-entropy alloy nitrides and high-entropy alloy oxides with a low surface roughness, a dense coating, and adjustable composition to meet the required properties for high-pressure die-casting die applications.

[0026] Combined with the above design and processing technology, the principle of the present invention is as follows:

[0027] Due to the too large difference in the thermal expansion coefficients between the high-entropy alloy ceramic temperature- and wear-resistant layer and the high-pressure die-casting die substrate, in order to avoid the peeling of the coating at high temperatures, a gradient layer structure and a nano-multilayer composite structure are adopted to form a gradual change in structure and composition, thereby improving the bonding strength between the coating and the substrate.

[0028] Utilize the high ionization rate of arc ion plating to prepare high-entropy alloy nitride nano-composite coating materials, which have good adhesion and a high deposition rate, improving the performance and production efficiency of the coating.

[0029] Compared with the formation of CrN and AlN compounds, the formation of Al2O3 and Cr2O3 compounds in a closed system of Al, Cr, O, and N atoms is more energetically favorable. This is because the formation of Al-O and Cr-O bonds reduces the Gibbs free energy of the system by 7 to 10 times that of Al-N and Cr-N bonds. The relatively high reactivity of O2 compared to N2 with respect to Al and Cr is also related to the difference in the binding energies of Al and Cr with O and N. The binding energies of Al and Cr with O are much higher than those of Al and Cr with N, which provides a higher tendency for the formation of Al / Cr-O bonds. Therefore, when there is a lack of O2 and a large amount of N2 in the vacuum chamber, that is, there are not enough O atoms to react with all the metal elements, some free metal atoms are left to form bonds with N. Therefore, oxides are preferentially formed after introducing O2. As the O2 flow rate increases, the transformation from nitrides to oxynitrides and then to oxides can be achieved, thereby enabling the adjustment of the coating composition, and further realizing the regulation of the coating structure and properties, and preparing an AlCrNbSiTiON nanocomposite coating with excellent properties to meet the required performance for high-pressure die-casting mold applications.

[0030] When depositing in a pure oxygen atmosphere, more arcs are generated on the target surface. The extension of the arcs on the target surface leads to an increase in the ejected large particles and an increase in the surface roughness of the coating. When depositing in a pure nitrogen atmosphere, local dense arcs are generated on the target surface, the surface roughness of the coating is lower, and the number of large particles is less. However, high-entropy alloy oxides have more excellent oxidation resistance, temperature resistance, and wear resistance than high-entropy alloy nitrides. Therefore, in the present invention, by introducing a mixed gas of N2 and O2 and adjusting the O2 flow rate and N2 flow rate, high-entropy alloy oxynitrides and high-entropy alloy oxides with lower surface roughness, dense coatings, and adjustable compositions can be generated.

[0031] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0032] The present invention provides an AlCrNbSiTiON high-entropy alloy oxynitride nanocomposite coating, which combines the excellent mechanical properties of high-entropy alloy nitrides with the specific high-temperature properties, oxidation resistance, and wear resistance of high-entropy alloy oxides. The high-entropy alloy oxynitride coating for high-pressure die-casting molds prepared not only has the excellent mechanical properties of high-entropy alloy nitrides but also has more excellent oxidation resistance, high-temperature stability, and wear resistance, which can ensure the long-term stable operation of high-pressure die-casting molds under high-temperature conditions. At the same time, by fully utilizing the nano-multilayer composite and gradient composite coating technologies, a gradual change in structure and composition is formed, reducing the mismatch degree of lattice constants and thermal expansion coefficients between the coating and the substrate, and having good adhesion.

[0033] The present invention provides a preparation method for an AlCrNbSiTiON high-entropy alloy oxynitride nanocomposite coating, which has good adhesion and a high deposition rate, improving the coating performance and production efficiency. Brief Description of the Drawings

[0034] Figure 1 It is a schematic diagram of the preparation device adopted in the embodiment. In the figure, 1 represents the AlCrNbSiTi target, 2 represents the Cr target, 3 represents the AlCrNbSiTi target, 4 represents the Cr target, 5 represents the sample holder, 6 represents the heating rod, and 7 represents the air extraction port;

[0035] Figure 2 It is a schematic diagram of the structure of the AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating. In the figure, 1 represents the matrix of the high-pressure die-casting mold, 2 represents the Cr bonding layer, 3 represents the CrN transition layer, 4 represents the CrN / AlCrNbSiTiN support layer, and 5 represents the AlCrNbSiTiON temperature- and wear-resistant layer;

[0036] Figure 3 It is the surface morphology diagram of the AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating in Example 2;

[0037] Figure 4 It is the cross-sectional morphology diagram of the AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating in Example 2;

[0038] Figure 5 They are the wear resistance test results of the AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coatings of the control group and Example 2 in sequence;

[0039] Figure 6 They are the surface morphology diagrams of the AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating in Example 2 after annealing at different temperatures in sequence;

[0040] Figure 7 It is the diagram of the change of element composition of the AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating in Example 2 after annealing at different temperatures. Detailed Embodiments

[0041] The present invention will be further described below by way of examples, but the present invention is not limited to the scope of the described examples. For the experimental methods without specific conditions in the following examples, they are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0042] In the preparation process of the following examples, the following is adopted as Figure 1The preparation device shown. The vacuum chamber of the device is surrounded by the furnace wall, and the size of the vacuum chamber is 800×800×800 mm. The vacuum chamber is provided with a vacuum pumping port 7, and the vacuum pumping unit pumps the vacuum chamber through the vacuum pumping port 7; the four corners of the vacuum chamber are heaters 6 with a heating power of 10 - 30 kW to improve the heating efficiency; 8 arc targets are installed on the furnace wall in 4 columns, with four Cr targets and four AlCrNbSiTi targets installed respectively, and the sample is placed on the sample holder 5. This layout greatly increases the plasma density in the vacuum chamber, and the workpiece is completely immersed in the plasma, resulting in a significant increase in the coating deposition rate, hardness, and adhesion. Due to the optimization of the target structure, the magnetic field distribution is more uniform, enabling the arc to strike evenly on the target surface and improving the coating uniformity.

[0043] Example 1

[0044] Preparation method of AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating:

[0045] (1) Use an ultrasonic cleaner to clean the matrix material of the high-pressure die-casting mold in acetone and alcohol for 15 min respectively to remove surface oil stains and other impurities. After drying, load it onto the sample holder in the vacuum chamber of the preparation device, prepare the arc ion plating equipment, and pump the vacuum until the vacuum degree in the vacuum chamber reaches 7×10 -3 Pa. At the same time, heat the vacuum chamber to 450 °C; control the rotation speed of the sample holder to be 1.5 r / min and the rotation speed of the sample to be 0.5 r / min. Adopt the general plasma etching method, introduce a mixed gas formed by argon and hydrogen, turn on the bias voltage and arc power supply of the Cr target, and perform plasma etching on the high-pressure die-casting mold under the conditions of a bias voltage of -150 V and a duty cycle of 70% to remove the oxides and adsorbed gases on the matrix surface and activate the surface, improving the bonding force between the coating and the matrix, and obtaining the activated matrix material of the high-pressure die-casting mold.

[0046] (2) After the plasma etching is completed, only introduce argon to control the ambient pressure at 0.5 Pa. Use the Cr target for deposition, keep the duty cycle of the Cr target unchanged, set the bias voltage to 100 V, and then deposit a Cr bonding layer with a thickness of 50 nm on the surface of the activated matrix material of the high-pressure die-casting mold.

[0047] (3) Stop introducing argon, introduce nitrogen into the preparation device and control the ambient pressure at 2 Pa. Use the Cr target for deposition, keep the duty cycle of the Cr target unchanged, set the bias voltage to 100 V, and continue to deposit a CrN transition layer with a thickness of 200 nm on the surface of the obtained Cr bonding layer.

[0048] (4) Continue to introduce nitrogen and adjust the ambient air pressure to 3.5 Pa. Use a Cr target and an AlCrNbSiTi target for deposition. Keep the duty cycle of the Cr target unchanged, set the bias voltage to 100 V. Turn on the arc power supply of the AlCrNbSiTi target, set the bias voltage to 100 V, adjust the pulse duty cycle of the AlCrNbSiTi target arc power supply to 20%. Subsequently, deposit CrN monolayers and AlCrNbSiTiN monolayers alternately in cycles. The thickness of the CrN monolayer is 20 nm, the thickness of the AlCrNbSiTiN monolayer is 20 nm, and the thickness of the single-cycle coating obtained by the combination of the two is 40 nm, forming a CrN / AlCrNbSiTiN support layer with a total thickness of 400 nm.

[0049] (5) Turn off the arc power supply of the Cr target, introduce 300 sccm of oxygen and adjust the nitrogen flow rate to keep the ambient air pressure at 3.5 Pa. Use the AlCrNbSiTi target for deposition. Keep the duty cycle unchanged, set the bias voltage to 150 V, and deposit an AlCrNbSiTiON temperature- and wear-resistant layer on the surface of the CrN / AlCrNbSiTiN support layer. The deposition time is 100 min. After the preparation is completed, it is naturally cooled to room temperature to obtain an AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating.

[0050] Example 2

[0051] Preparation method of an AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating:

[0052] (1) Use an ultrasonic cleaner to clean the high-pressure die-casting mold matrix material in acetone and alcohol for 15 min respectively to remove impurities such as oil stains on the surface. After drying, it is loaded onto the sample holder in the vacuum chamber of the preparation device. Prepare the arc ion plating equipment and evacuate to a vacuum degree of 7×10 -3 Pa in the vacuum chamber. At the same time, heat the vacuum chamber to 450 °C. Control the rotation speed of the sample holder to be 1.5 r / min and the rotation speed of the sample to be 0.5 r / min. Use the general plasma etching method, introduce a mixed gas formed by argon and hydrogen, turn on the bias voltage and arc power supply of the Cr target, and perform plasma etching on the high-pressure die-casting mold under the conditions of a bias voltage of -150 V and a duty cycle of 70% to remove oxides and adsorbed gases on the matrix surface and activate the surface, improving the adhesion between the coating and the matrix, and obtaining an activated high-pressure die-casting mold matrix material.

[0053] (2) After the plasma etching is completed, only introduce argon to control the ambient air pressure at 0.5 Pa. Use the Cr target for deposition. Keep the duty cycle of the Cr target unchanged, set the bias voltage to 100 V, and then deposit a Cr bonding layer with a thickness of 50 nm on the surface of the activated high-pressure die-casting mold matrix material.

[0054] (3) Stop introducing argon gas, introduce nitrogen gas into the preparation device and control the ambient air pressure at 2 Pa. Use a Cr target for deposition, keep the duty cycle of the Cr target unchanged, set the bias voltage at 100 V, and continue to deposit on the surface of the obtained Cr bonding layer to form a CrN transition layer with a thickness of 200 nm;

[0055] (4) Continue to introduce nitrogen gas and adjust the ambient air pressure to 3.5 Pa. Use a Cr target and an AlCrNbSiTi target for deposition, keep the duty cycle of the Cr target unchanged, set the bias voltage at 100 V; turn on the arc power supply of the AlCrNbSiTi target, set the bias voltage at 100 V, adjust the pulse duty cycle of the AlCrNbSiTi target arc power supply to 60%, and then alternately deposit CrN single layers and AlCrNbSiTiN single layers in cycles. The thickness of the CrN single layer is 10 nm, the thickness of the AlCrNbSiTiN single layer is 20 nm, and the thickness of the single-cycle coating obtained by the combination of the two is 30 nm, forming a CrN / AlCrNbSiTiN support layer with a total thickness of 400 nm;

[0056] (5) Turn off the arc power supply of the Cr target, introduce 100 sccm of oxygen and adjust the nitrogen gas flow rate to keep the ambient air pressure at 3.5 Pa. Use the AlCrNbSiTi target for deposition, keep the duty cycle unchanged, set the bias voltage at 150 V, and deposit an AlCrNbSiTiON temperature- and wear-resistant layer on the surface of the CrN / AlCrNbSiTiN support layer. The deposition time is 70 min; after the preparation is completed, it is naturally cooled to room temperature to obtain an AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating.

[0057] Use a field emission scanning electron microscope (MIRA3 TESCAN) to observe the surface microtopography of the AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating obtained in this example. From Figure 3 It can be seen that the particle size on the coating surface is small and there are no obvious defects.

[0058] Use a field emission scanning electron microscope (MIRA3 TESCAN) to observe the cross-sectional microtopography of the AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating obtained in this example. From Figure 4 It can be seen that the coating and the substrate are closely bonded and there are no obvious pores.

[0059] Test the wear resistance of the AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating through a friction and wear tester, using the corresponding nitride coating without oxygen as the control group. From Figure 5 the morphology of the worn coating, it can be seen that the wear scar width of the corresponding nitride coating is 276 μm, while the wear scar width of the oxygen-containing coating in this example is further reduced to 140 μm, showing good wear resistance compared with the nitride coating.

[0060] The AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating of this embodiment was annealed at 800 °C, 900 °C, 1000 °C, and 1100 °C respectively, and the surface morphology of the coating after annealing at different temperatures was observed and the elemental composition changes were analyzed. From Figure 6 It can be seen that after the coating was annealed at 800 - 1000 °C, there was no obvious change on the surface of the coating; From Figure 7 It can be seen that the coating composition did not change significantly with the increase of the annealing temperature, showing excellent chemical composition stability, indicating that the coating has excellent thermal stability.

[0061] Example 3

[0062] Preparation method of AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating:

[0063] (1) Use an ultrasonic cleaner to clean the matrix material of the high-pressure die-casting mold in acetone and alcohol for 15 min respectively to remove impurities such as oil stains on the surface. After drying, load it onto the sample rack in the vacuum chamber of the preparation device, prepare the arc ion plating equipment, and evacuate to a vacuum degree of 7×10 -3 Pa in the vacuum chamber. At the same time, heat the vacuum chamber to 450 °C; control the rotation speed of the sample rack to be 1.5 r / min and the rotation speed of the sample to be 0.5 r / min. Adopt the general plasma etching method, introduce a mixed gas formed by argon and hydrogen, turn on the bias voltage and arc power supply of the Cr target, and perform plasma etching on the high-pressure die-casting mold under the conditions of a bias voltage of -150 V and a duty cycle of 70% to remove the oxides and adsorbed gases on the matrix surface and activate the surface, improving the bonding force between the coating and the matrix to obtain the activated matrix material of the high-pressure die-casting mold;

[0064] (2) After the plasma etching is completed, only introduce argon to control the ambient pressure at 0.5 Pa, use the Cr target for deposition, keep the duty cycle of the Cr target unchanged, set the bias voltage to 100 V, and then deposit a Cr bonding layer with a thickness of 50 nm on the surface of the activated matrix material of the high-pressure die-casting mold;

[0065] (3) Stop introducing argon, introduce nitrogen into the preparation device and control the ambient pressure at 2 Pa, use the Cr target for deposition, keep the duty cycle of the Cr target unchanged, set the bias voltage to 100 V, and continue to deposit a CrN transition layer with a thickness of 200 nm on the surface of the obtained Cr bonding layer;

[0066] (4) Continuously introduce nitrogen and adjust the ambient air pressure to 3.5 Pa. Use a Cr target and an AlCrNbSiTi target for deposition. Keep the duty cycle of the Cr target unchanged and set the bias voltage to 100 V. Turn on the arc power supply of the AlCrNbSiTi target, set the bias voltage to 100 V, adjust the pulse duty cycle of the AlCrNbSiTi target arc power supply to 80%. Subsequently, deposit CrN monolayers and AlCrNbSiTiN monolayers alternately in cycles. The thickness of the CrN monolayer is 10 nm, the thickness of the AlCrNbSiTiN monolayer is 20 nm, and the thickness of the single-cycle coating obtained by combining the two is 30 nm, forming a CrN / AlCrNbSiTiN support layer with a total thickness of 400 nm.

[0067] (5) Turn off the Cr target arc power supply, introduce 250 sccm of oxygen and adjust the nitrogen flow rate to keep the ambient air pressure at 3.5 Pa. Use the AlCrNbSiTi target for deposition. Keep the duty cycle unchanged and set the bias voltage to 150 V. Deposit an AlCrNbSiTiON temperature- and wear-resistant layer on the surface of the CrN / AlCrNbSiTiN support layer, and the deposition time is 70 min. After the preparation is completed, cool it naturally to room temperature to obtain an AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating.

[0068] Example 4

[0069] Preparation method of AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating:

[0070] (1) Use an ultrasonic cleaner to clean the high-pressure die-casting mold matrix material in acetone and alcohol for 15 min respectively to remove surface oil and other impurities. After drying, load it onto the sample rack in the vacuum chamber of the preparation device, prepare the arc ion plating equipment, and evacuate to a vacuum degree of 7×10 -3 Pa in the vacuum chamber. At the same time, heat the vacuum chamber to 450 °C. Control the rotation speed of the sample rack to 1.5 r / min and the rotation speed of the sample to 0.5 r / min. Adopt the general plasma etching method, introduce a mixed gas formed by argon and hydrogen, turn on the bias voltage and arc power supply of the Cr target, and perform plasma etching on the high-pressure die-casting mold under the conditions of a bias voltage of -150 V and a duty cycle of 70% to remove the oxides and adsorbed gases on the matrix surface and activate the surface, improving the adhesion between the coating and the matrix, and obtaining an activated high-pressure die-casting mold matrix material.

[0071] (2) After the plasma etching is completed, only introduce argon to control the ambient air pressure at 0.5 Pa. Use the Cr target for deposition. Keep the duty cycle of the Cr target unchanged and set the bias voltage to 100 V. Subsequently, deposit a Cr bonding layer with a thickness of 50 nm on the surface of the activated high-pressure die-casting mold matrix material.

[0072] (3) Stop introducing argon gas, introduce nitrogen gas into the preparation device and control the ambient air pressure at 2 Pa. Use a Cr target for deposition, keep the duty cycle of the Cr target unchanged, set the bias voltage at 100 V, and continue to deposit on the surface of the obtained Cr bonding layer to form a CrN transition layer with a thickness of 200 nm;

[0073] (4) Continue to introduce nitrogen gas and adjust the ambient air pressure to 3.5 Pa. Use a Cr target and an AlCrNbSiTi target for deposition, keep the duty cycle of the Cr target unchanged, set the bias voltage at 100 V; turn on the arc power supply of the AlCrNbSiTi target, set the bias voltage at 100 V, adjust the pulse duty cycle of the AlCrNbSiTi target arc power supply to 60%, and then alternately deposit CrN single layers and AlCrNbSiTiN single layers in cycles. The thickness of the CrN single layer is 10 nm, the thickness of the AlCrNbSiTiN single layer is 20 nm, and the thickness of the single-cycle coating obtained by combining the two is 30 nm, forming a CrN / AlCrNbSiTiN support layer with a total thickness of 400 nm;

[0074] (5) Turn off the arc power supply of the Cr target, introduce 100 sccm of oxygen and adjust the nitrogen gas flow rate to keep the ambient air pressure at 5 Pa. Use the AlCrNbSiTi target for deposition, keep the duty cycle unchanged, set the bias voltage at 200 V, and deposit an AlCrNbSiTiON temperature- and wear-resistant layer on the surface of the CrN / AlCrNbSiTiN support layer. The deposition time is 70 min; after the preparation is completed, naturally cool to room temperature to obtain an AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating.

[0075] Example 5

[0076] Preparation method of AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating:

[0077] (1) Use an ultrasonic cleaner to clean the high-pressure die-casting mold matrix material in acetone and alcohol for 15 min respectively to remove impurities such as oil stains on the surface. After drying, load it onto the sample rack in the vacuum chamber of the preparation device, prepare the arc ion plating equipment, and evacuate to a vacuum degree of 7×10 -3 Pa in the vacuum chamber. At the same time, heat the vacuum chamber to 450 °C; control the rotation speed of the sample rack at 1.5 r / min and the rotation speed of the sample at 0.5 r / min. Use the general plasma etching method, introduce a mixed gas formed by argon gas and hydrogen gas, turn on the bias voltage and arc power supply of the Cr target, and perform plasma etching on the high-pressure die-casting mold under the conditions of a bias voltage of -150 V and a duty cycle of 70% to remove oxides and adsorbed gases on the matrix surface and activate the surface, improving the bonding force between the coating and the matrix, and obtaining an activated high-pressure die-casting mold matrix material;

[0078] (2) After the plasma etching is completed, only argon is introduced to control the ambient air pressure at 0.5 Pa. Deposition is carried out using a Cr target while keeping the duty cycle of the Cr target unchanged. The bias voltage is set to 100 V, and then a Cr bonding layer with a thickness of 50 nm is deposited on the surface of the activated high-pressure die-casting mold matrix material;

[0079] (3) Stop introducing argon, introduce nitrogen into the preparation device and control the ambient air pressure at 2 Pa. Deposition is carried out using a Cr target while keeping the duty cycle of the Cr target unchanged. The bias voltage is set to 100 V, and a CrN transition layer with a thickness of 200 nm is continuously deposited on the surface of the obtained Cr bonding layer;

[0080] (4) Continue to introduce nitrogen and adjust the ambient air pressure to 3.5 Pa. Deposition is carried out using a Cr target and an AlCrNbSiTi target while keeping the duty cycle of the Cr target unchanged. The bias voltage is set to 100 V; turn on the arc power supply of the AlCrNbSiTi target, set the bias voltage to 100 V, and adjust the pulse duty cycle of the AlCrNbSiTi target arc power supply to 60%. Then, CrN monolayers and AlCrNbSiTiN monolayers are alternately deposited in cycles. The thickness of the CrN monolayer is 10 nm, the thickness of the AlCrNbSiTiN monolayer is 20 nm, and the thickness of the single-cycle coating obtained by the combination of the two is 30 nm, forming a CrN / AlCrNbSiTiN support layer with a total thickness of 400 nm;

[0081] (5) Turn off the arc power supply of the Cr target, introduce 250 sccm of oxygen and adjust the nitrogen flow rate to keep the ambient air pressure at 5 Pa. Deposition is carried out using the AlCrNbSiTi target while keeping the duty cycle unchanged. The bias voltage is set to 200 V, and an AlCrNbSiTiON temperature-resistant and wear-resistant layer is deposited on the surface of the CrN / AlCrNbSiTiN support layer. The deposition time is 70 min; after the preparation is completed, it is naturally cooled to room temperature to obtain an AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating.

[0082] Example 6

[0083] Preparation method of AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating:

[0084] (1) Use an ultrasonic cleaner to clean the high-pressure die-casting mold matrix material in acetone and alcohol for 15 min respectively to remove impurities such as oil stains on the surface. After drying, it is loaded onto the sample rack in the vacuum chamber of the preparation device, and the arc ion plating equipment is prepared. The vacuum is pumped until the vacuum degree in the vacuum chamber reaches 7*10 -3Pa, and at the same time heat the vacuum chamber to 450 °C; control the rotation speed of the sample holder to 1.5 r / min and the rotation speed of the sample to 0.5 r / min. Using the general plasma etching method, introduce a mixed gas formed by argon and hydrogen, turn on the bias voltage and arc power supply of the Cr target, and perform plasma etching on the high-pressure die-casting mold under the conditions of a bias voltage of -150 V and a duty cycle of 70% to remove the oxides and adsorbed gases on the substrate surface and activate the surface, improving the bonding force between the coating and the substrate, and obtaining an activated high-pressure die-casting mold substrate material;

[0085] (2) After the plasma etching is completed, only introduce argon to control the ambient air pressure at 0.5 Pa, use the Cr target for deposition, keep the duty cycle of the Cr target unchanged, set the bias voltage to 100 V, and then deposit a Cr bonding layer with a thickness of 50 nm on the surface of the activated high-pressure die-casting mold substrate material;

[0086] (3) Stop introducing argon, introduce nitrogen into the preparation device and control the ambient air pressure at 2 Pa, use the Cr target for deposition, keep the duty cycle of the Cr target unchanged, set the bias voltage to 100 V, and continue to deposit a CrN transition layer with a thickness of 200 nm on the surface of the obtained Cr bonding layer;

[0087] (4) Continue to introduce nitrogen and adjust the ambient air pressure to 3.5 Pa, use the Cr target and the AlCrNbSiTi target for deposition, keep the duty cycle of the Cr target unchanged, set the bias voltage to 100 V; turn on the arc power supply of the AlCrNbSiTi target, set the bias voltage to 100 V, adjust the pulse duty cycle of the AlCrNbSiTi target arc power supply to 80%, and then alternately deposit a CrN single layer and an AlCrNbSiTiN single layer in a cycle. The thickness of the CrN single layer is 10 nm, the thickness of the AlCrNbSiTiN single layer is 20 nm, and the thickness of the single-cycle coating obtained by the combination of the two is 30 nm, forming a CrN / AlCrNbSiTiN support layer with a total thickness of 400 nm;

[0088] (5) Turn off the arc power supply of the Cr target, introduce 500 sccm of oxygen and adjust the nitrogen flow rate to keep the ambient air pressure at 5 Pa, use the AlCrNbSiTi target for deposition, keep the duty cycle unchanged, set the bias voltage to 250 V, and deposit an AlCrNbSiTiON temperature-resistant and wear-resistant layer on the surface of the CrN / AlCrNbSiTiN support layer. The deposition time is 120 min; after the preparation is completed, naturally cool to room temperature to obtain an AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating.

[0089] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative efforts. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field according to the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art shall fall within the protection scope determined by the claims.

Claims

1. An AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating, characterized in that, The AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating has a gradient structure and includes a bonding layer, a transition layer, a support layer, and a temperature- and wear-resistant layer. The bonding layer is the contact layer with the substrate. In terms of the composition of each layer, the bonding layer is a Cr bonding layer, the transition layer is a CrN transition layer, the support layer is a CrN / AlCrNbSiTiN support layer, and the temperature- and wear-resistant layer is an AlCrNbSiTiON temperature- and wear-resistant layer. In the AlCrNbSiTiON temperature- and wear-resistant layer, the molar ratio relationship between O and N satisfies 1 / 20 ≤ O / N ≤ 20 / 1.

2. The AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating according to claim 1, wherein: The CrN / AlCrNbSiTiN support layer is composed of a CrN single layer and an AlCrNbSiTiN single layer compounded in a periodic alternating form.

3. The AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating according to claim 2, wherein: The thickness of the Cr bonding layer is 10 - 100 nm, the thickness of the CrN transition layer is 200 - 800 nm, and the thickness of the CrN / AlCrNbSiTiN support layer is 400 - 1500 nm. Among them, the thickness of the CrN single layer is 10 - 30 nm, the thickness of the AlCrNbSiTiN single layer is 5 - 20 nm, and the thickness of a single-period coating obtained by compounding the CrN single layer and the AlCrNbSiTiN single layer is 15 - 50 nm.

4. A method for preparing an AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating according to any one of claims 1 to 3, using an arc ion plating process, characterized in that, It includes the following steps: (1) The matrix material of the high-pressure die-casting mold is etched by plasma to remove surface impurities and activate the surface, obtaining an activated matrix material of the high-pressure die-casting mold. (2) In an argon atmosphere, a Cr bonding layer is deposited on the surface of the activated matrix material of the high-pressure die-casting mold. (3) In a nitrogen atmosphere, a CrN transition layer is deposited on the surface of the Cr bonding layer. (4) In a nitrogen atmosphere, a CrN single layer and an AlCrNbSiTiN single layer are deposited on the surface of the CrN transition layer in a periodic alternating manner to form a CrN / AlCrNbSiTiN support layer. (5) In an oxygen and nitrogen atmosphere, an AlCrNbSiTiON temperature- and wear-resistant layer is deposited on the surface of the CrN / AlCrNbSiTiN support layer, completing the preparation of the AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating.

5. The method according to claim 4, wherein: During the preparation process of the AlCrNbSiTiON high-entropy alloy nitride oxide nanocomposite coating, the ambient temperature is maintained at 300 - 500 °C.

6. The method according to claim 4, characterized in that: In the step (1), the pulse duty cycle of the arc power supply of the Cr target used for the plasma etching is 10% - 80%, and the bias voltage is -50 - -150 V.

7. The method according to claim 4, characterized in that: In the step (2), the deposition uses a Cr target. The ambient pressure during deposition is 0.1 - 1 Pa, the deposition bias voltage is 50 - 150 V, and the pulse duty cycle of the arc power supply of the Cr target is 10% - 80%.

8. The method according to claim 4, characterized in that: In the step (3), the deposition uses a Cr target. The ambient pressure during deposition is 1 - 3 Pa, the deposition bias voltage is 50 - 150 V, and the pulse duty cycle of the arc power supply of the Cr target is 10% - 80%.

9. The method according to claim 4, wherein: In the step (4), Cr target and AlCrNbSiTi target are used for deposition to form a single layer of CrN and a single layer of AlCrNbSiTiN respectively. The ambient air pressure during deposition is 2 - 5 Pa, the deposition bias voltage of the Cr target is 50 - 150 V, and the pulse duty cycle of the arc power supply of the Cr target is 10% - 80%; the deposition bias voltage of the AlCrNbSiTi target is 50 - 250 V, and the pulse duty cycle of the arc power supply of the AlCrNbSiTi target is 20% - 80%.

10. The method according to claim 4, wherein: In the step (5), the AlCrNbSiTi target is used for deposition. The ambient air pressure during deposition is 2 - 5 Pa, the oxygen flow rate is 10 - 500 sccm, the deposition bias voltage is 50 - 250 V, the pulse duty cycle of the arc power supply of the AlCrNbSiTi target is 20% - 80%, and the deposition time is 30 - 120 min.

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