Alcrtisi n nanocomposite coating with nanocrystalline / amorphous composite structure or single amorphous structure and preparation thereof

Abstract

The application discloses an AlCrTiSiN composite coating with a nanocrystal / amorphous composite structure or a single amorphous structure and a preparation method of the AlCrTiSiN composite coating. The coating is prepared by adopting a pulse direct current magnetron sputtering and radio frequency direct current magnetron sputtering composite technology, and an AlCrTi alloy target and a single Si target are selected as the target material. The alloy target is connected with a direct current power supply, and the single Si target is connected with a radio frequency power supply. When the coating is plated, the AlCrTi alloy target is turned on, the bias voltage is adjusted to be -20-150 V, the vacuum chamber pressure is adjusted to be 0.3-1.0 Pa, an AlCrTi transition layer is deposited, and the deposition time is 10-30 min. The AlCrTi is kept on and the reaction gas N2 is introduced, the Si target is turned on, and the AlCrTiSiN nanocomposite coating is deposited. The AlCrTiSiN nanocomposite coating prepared by the application has the advantages of simple preparation process, controllable composition, good repeatability, easy industrial production and strong practicability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coating and its preparation technology, in particular to an AlCrTiSiN nanocomposite coating with nanocrystalline / amorphous composite structure or single amorphous structure and its preparation. BACKGROUND

[0002] With people paying more and more attention to the service life and working efficiency of materials and parts in harsh environments, coating a layer of coating on the surface of materials and parts can effectively provide a layer of "protective barrier". Among them, nitride coating is widely used in mechanical parts, cutting tools and molds due to its high hardness, good wear resistance and excellent oxidation resistance, such as the widely used TiN and CrN binary coating, followed by AlCrN, AlTiN, AlCrTiN, CrAlSiN and other multi-component coatings. In order to explore the coating with better protective performance, Si element is doped based on AlCrTiN coating to prepare AlCrTiSiN nanocomposite coating with better performance. SUMMARY

[0003] The purpose of the present application is to provide an AlCrTiSiN nanocomposite coating with nanocrystalline / amorphous composite structure or single amorphous structure and its preparation. By using pulse direct current magnetron sputtering and radio frequency direct current magnetron sputtering composite technology, stable process parameters are optimized and determined, so as to prepare AlCrTiSiN nanocomposite coating with good high-temperature oxidation resistance and mechanical properties.

[0004] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0005] An AlCrTiSiN nanocomposite coating with nanocrystalline / amorphous composite structure or single amorphous structure, which is obtained by doping Si into AlCrTiN coating, and the Si doping amount is greater than 0.1 and less than or equal to 30 at.%. When the Si doping amount is greater than 0.1 and less than or equal to 4 at.%, the nanocomposite coating has a face-centered cubic structure and an amorphous phase composite structure, and when the Si doping amount is higher than 4 at.%, the nanocomposite coating is in an amorphous state.

[0006] In the nanocomposite coating with nanocrystalline / amorphous composite structure, when Si is doped into the AlCrTiN coating, the solid solution strengthening and fine-grain strengthening effects dominate, a part of Si is dissolved in the (Al,Cr,Ti)N solid solution phase, and a part of Si forms amorphous phase Si x N y .

[0007] In the nanocomposite coating with single amorphous state, all atoms are arranged in disorder, and there is no obvious grain boundary, which can further improve the high-temperature oxidation resistance of the composite coating.

[0008] The AlCrTiSiN nanocomposite coating has Al content of 21-26 at%, N content of 55-57 at%, Cr content of 7-9 at%, Ti content of 5-6 at%, and Si content of 0.1-30 at%.

[0009] The AlCrTiSiN nanocomposite coating is deposited on a stainless steel sheet 304, a single crystal Si sheet or a cemented carbide substrate, and an AlCrTi transition layer is further deposited between the substrate and the AlCrTiSiN nanocomposite coating.

[0010] The AlCrTiSiN nanocomposite coating has a thickness of 1.5-4 μm, and the AlCrTi transition layer has a thickness of 100-300 nm.

[0011] The AlCrTiSiN nanocomposite coating has a hardness of 20-40 GPa and an elastic modulus of 268-400 GPa, and after high-temperature oxidation at 800-1100℃, a continuous and dense oxide film is formed on the surface of the coating, which hinders the diffusion of O element and exhibits excellent high-temperature oxidation resistance.

[0012] The AlCrTiSiN nanocomposite coating with nanocrystalline / amorphous composite structure or single amorphous structure is prepared by using pulse direct current magnetron sputtering and radio frequency direct current magnetron sputtering composite technology to deposit the AlCrTiSiN nanocomposite coating with good high-temperature oxidation resistance and mechanical properties on the substrate. The method specifically comprises the following steps:

[0013] (1) fixing the substrate sample to be deposited on the rotating frame, placing it in the furnace and closing the furnace door, wherein the distance between the target material and the sample is 50-300 mm;

[0014] (2) vacuumizing by using a mechanical pump and a molecular pump, and when the vacuum degree reaches 5×10 -4 above, heating the resistance to 200-400℃; when the temperature in the furnace reaches 200-400℃ and the vacuum degree again reaches 5×10 -4 above, introducing Ar gas, setting the Ar gas flow rate to 30-100 sccm, adjusting the throttle valve to keep the pressure in the vacuum chamber at 0.8-2 Pa, and then applying a bias voltage of -200 to -800 V to perform glow cleaning on the sample, and the cleaning time is 10-30 min;

[0015] (3) after the glow cleaning is completed, adjusting the bias voltage to -20 to 150 V and increasing the pressure in the vacuum chamber to 0.3-1 Pa, turning on the direct current power supply, setting the target power of the AlCrTi alloy target to 50-200 W, depositing the AlCrTi transition layer, and the deposition time is 10-30 min;

[0016] (4) keeping the target power of the AlCrTi alloy target as 50-200 W and the vacuum chamber pressure as 0.3-1 Pa, inputting N2 gas, adjusting the N2 gas flow to be 10-60 sccm, adjusting the bias voltage to be -20-150 V, opening the single-element Si target connected with the radio frequency power source, adjusting the Si target power to be 5-150 W, and depositing for 120-300 min;

[0017] In the step (1), the sample is cleaned before use, and the cleaning process is as follows: sequentially using acetone, alcohol and deionized water for ultrasonic cleaning for 15-30 min, and then drying.

[0018] Further, the target material is selected as two identical AlCrTi alloy targets (atomic ratio of 50:30:20, purity of 99.8%) and a single-element Si target (purity of 99.99%); the two AlCrTi alloy targets are connected with the direct current power source, and the single-element Si target is connected with the radio frequency power source; the atomic ratio of Al, Cr and Ti in the AlCrTi alloy target is 50:30:20, and the purity is 99.8%; the purity of the single-element Si target is 99.99%.

[0019] The thickness of the AlCrTiSiN nano-composite coating is realized by adjusting the target power, the rotating speed of the rotating frame and the deposition time; the Si content in the AlCrTiSiN nano-composite coating gradually increases with the increase of the Si target power.

[0020] The design mechanism of the application is as follows:

[0021] The hardness, wear resistance and high-temperature oxidation resistance of the quaternary AlCrTiN coating are more excellent than those of the ternary AlCrN and AlTiN coatings. In order to further improve the high-temperature oxidation resistance of the AlCrTiN coating and maintain good mechanical properties, the application designs an AlCrTiSiN nanocomposite coating with a nanocrystalline / amorphous composite structure or a single amorphous structure. In the AlCrTiSiN nanocomposite coating, the solid solution strengthening effect of the multiple elements in the coating is generated in the deposition process, so as to enhance the mechanical properties of the coating. A part of Si is dissolved into the face-centered cubic lattice to form solid solution strengthening, and another part of Si and N form amorphous Si3N4, so as to refine the grain size, hinder the grain boundary slip and crack diffusion between crystal faces. In addition, the Gibbs free energy of Al2O3 is lower than that of Cr2O3 and TiO2 at high temperature, that is, the Al element is more likely to react with O to form Al2O3, so that a mixed oxide film mainly composed of Al2O3 can be rapidly formed on the surface of the coating at high temperature. The oxide film can hinder the inward diffusion of O elements and the outward diffusion of the internal elements of the coating, so as to enhance the high-temperature oxidation resistance of the coating. Therefore, the AlCrTiSiN nanocomposite coating in the application has excellent mechanical properties, tribological properties and high-temperature oxidation resistance, and has a very good application prospect in the fields of cutting, aerospace, nuclear industry and the like.

[0022] The advantages and beneficial effects of the application are as follows:

[0023] 1. The AlCrTiSiN nanocomposite coating developed in the application is deposited by using a pulse direct current magnetron sputtering and radio frequency direct current magnetron sputtering composite technology. The pulse direct current magnetron sputtering technology has a high pulse peak power, and the high-ionized beam current does not contain large particles, so as to effectively reduce the surface roughness of the coating, improve the density of the coating and prevent the substrate temperature from being significantly increased. The radio frequency magnetron sputtering technology is suitable for depositing almost all materials including metals and non-metals, and has a high deposition rate, a dense coating, a high purity and a strong film-substrate adhesion.

[0024] 2. The AlCrTiSiN nanocomposite coating developed in the application has a dense structure and small grain size. When the Si content is 0.1-4at%, a part of Si is dissolved in the (Al,Cr,Ti)N solid solution phase, and another part of Si forms amorphous Si3N4. x N y When the Si content is higher than 4at%, the coating is a single amorphous phase.

[0025] 3. The AlCrTiSiN nanocomposite coating developed in the application has high hardness, toughness and wear resistance, a low friction coefficient and excellent high-temperature oxidation resistance.

[0026] 4. The AlCrTiSiN nanocomposite coating prepared by the method has simple preparation process, good repeatability, and can be applied to cutting, aerospace, nuclear industry and automobile manufacturing, and has strong practicability. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The XRD diffraction spectrum of the AlCrTiSiN nanocomposite coating prepared by the pulse direct current magnetron sputtering and radio frequency direct current magnetron sputtering composite technology when the Si target power is 50 W is shown in the figure. In the figure, the horizontal coordinate 2theta represents the diffraction angle (deg.), and the vertical coordinate Intensity represents the intensity (a.u.).

[0028] Figure 2 The surface morphology diagram of the AlCrTiSiN nanocomposite coating prepared by the pulse direct current magnetron sputtering and radio frequency direct current magnetron sputtering composite technology when the Si target power is 50 W.

[0029] Figure 3 The cross-sectional morphology diagram of the AlCrTiSiN nanocomposite coating prepared by the pulse direct current magnetron sputtering and radio frequency direct current magnetron sputtering composite technology when the Si target power is 50 W.

[0030] Figure 4 The cross-sectional morphology diagram of the AlCrTiSiN nanocomposite coating prepared by the pulse direct current magnetron sputtering and radio frequency direct current magnetron sputtering composite technology when the Si target power is 50 W and after 900℃ high temperature oxidation for 6h.

[0031] Figure 5 The cross-sectional morphology diagram of the AlCrTiSiN nanocomposite coating prepared by the pulse direct current magnetron sputtering and radio frequency direct current magnetron sputtering composite technology when the Si target power is 50 W and after 1100℃ high temperature oxidation for 6h.

[0032] Figure 6 The XRD diffraction spectrum of the AlCrTiSiN nanocomposite coating prepared by the pulse direct current magnetron sputtering and radio frequency direct current magnetron sputtering composite technology when the Si target power is 100 W is shown in the figure. In the figure, the horizontal coordinate 2theta represents the diffraction angle (deg.), and the vertical coordinate Intensity represents the intensity (a.u.).

[0033] Figure 7 The cross-sectional morphology diagram of the AlCrTiSiN nanocomposite coating prepared by the pulse direct current magnetron sputtering and radio frequency direct current magnetron sputtering composite technology when the Si target power is 100 W and after 900℃ high temperature oxidation for 6h.

[0034] Figure 8XRD diffraction spectrum of AlCrTiSiN nanocomposite coating prepared by pulse direct current magnetron sputtering and radio frequency direct current magnetron sputtering composite technology at Si target power of 100 W after high temperature oxidation at 1100 DEG C. In the figure, the horizontal coordinate 2theta represents diffraction angle (deg.), and the vertical coordinate Intensity represents intensity (a.u.).

[0035] Figure 9 Cross-section morphology of AlCrTiSiN nanocomposite coating prepared by pulse direct current magnetron sputtering and radio frequency direct current magnetron sputtering composite technology at Si target power of 100 W after high temperature oxidation at 1100 DEG C for 6 h.

[0036] Figure 10 Cross-section TEM morphology of AlCrTiSiN nanocomposite coating prepared by pulse direct current magnetron sputtering and radio frequency direct current magnetron sputtering composite technology at Si target power of 150 W; wherein: (a) bright field image; (b) selected area diffraction ring.

[0037] Figure 11 Cross-section morphology of AlCrTiSiN nanocomposite coating prepared by pulse direct current magnetron sputtering and radio frequency direct current magnetron sputtering composite technology at Si target power of 150 W after high temperature oxidation at 900 DEG C for 6 h.

[0038] Figure 12 Cross-section morphology of AlCrTiSiN nanocomposite coating prepared by pulse direct current magnetron sputtering and radio frequency direct current magnetron sputtering composite technology at Si target power of 150 W after high temperature oxidation at 1100 DEG C for 6 h. DETAILED DESCRIPTION

[0039] The application will be further described in detail by examples.

[0040] The application provides an AlCrTiSiN nanocomposite coating with nanocrystal / amorphous composite structure or single amorphous structure, which is mainly composed of three layers in sequence of substrate→AlCrTi transition layer→AlCrTiSiN nanocomposite coating. In the AlCrTiSiN nanocomposite coating, the content of Al is 21-26 at%, the content of N is 55-57 at%, the content of Cr is 7-9 at%, the content of Ti is 5-6 at%, and the content of Si is 0.1-30 at%; in the coating, Al element is mainly used except N element, and the content of Si gradually increases with the increase of Si target power; when the AlCrTiSiN nanocomposite coating is high-temperature oxidized, Al, Cr and Si elements in the coating react with O element to respectively generate Al2O3, Cr2O3 and SiO2, and a thin and dense mixed oxide film is formed on the surface of the coating, which can effectively prevent O element from further oxidizing the internal structure of the coating.

[0041] The AlCrTiSiN nanocomposite coatings with different Si contents exhibit a face-centered cubic (AlCrTi)N solid solution phase when the Si content is between 0.1% and 4 at%, and an amorphous phase when the Si content exceeds 4 at%. When a small amount of Si is incorporated into the AlCrTiN coating, the solid solution strengthening effect dominates. When the Si content exceeds a critical value, the AlCrTiSiN nanocomposite coating becomes amorphous, which can further improve the microstructure and mechanical properties of the coating. These AlCrTiSiN nanocomposite coatings with different Si contents are prepared using a combination of pulsed DC magnetron sputtering and radio frequency DC magnetron sputtering techniques.

[0042] Example 1:

[0043] This embodiment describes the deposition of an AlCrTiSiN nanocomposite coating with a nanocrystalline / amorphous composite structure or a single amorphous structure on a single-sided polished Si wafer. The Si wafer was ultrasonically cleaned sequentially with acetone, alcohol, and deionized water for 20 minutes, and then dried. The cleaned samples were then sequentially fixed onto a rotating frame, which was placed inside a furnace with the furnace door closed. The distance between the target and the sample was 150 mm, and the rotating frame rotated at 15 r / min. Two identical AlCrTi alloy targets (atomic ratio 50:30:20, purity 99.8%) and a single-element Si target (purity 99.99%) were used. The two AlCrTi alloy targets were connected to a DC power supply, and the single-element Si target was connected to an RF power supply. A mechanical pump and a molecular pump were used to evacuate the vacuum until a vacuum level of 5 × 10⁻⁶ was reached. -4 After that, turn on the heating resistor and heat to 300℃. When the furnace temperature reaches 300℃ and the vacuum degree reaches 5×10 again... -4 At the above stage, open the Ar gas flow valve to introduce Ar gas, set the Ar gas flow rate to 60 sccm, adjust the throttle valve to maintain the vacuum chamber pressure at 1 Pa, and then apply a bias voltage of -250V to perform glow discharge cleaning on the sample for 15 min. After glow discharge cleaning, adjust the bias voltage to -60V and the vacuum chamber pressure to 0.5 Pa, turn on the DC power supply, set the target power of the AlCrTi alloy target to 150W, and deposit the AlCrTi transition layer for 15 min, with a transition layer thickness of approximately 150 nm. Next, deposit the AlCrTiSiN nanocomposite coating, maintaining the AlCrTi alloy target power at 150W and the vacuum chamber pressure at 0.5 Pa, introducing N2 gas at a flow rate of 20 sccm to achieve an N2:Ar gas ratio of 1:3, adjusting the bias voltage to -90V, turning on the elemental Si target connected to the RF power supply at 50W, and depositing for 180 min. After deposition, the target power supply, heating resistor and gas flow valve are turned off. When the temperature inside the furnace is below 80°C, the sample is taken out to obtain AlCrTiSiN nanocomposite coating.

[0044] In this embodiment, the Al, Cr, Ti, Si and N in the coating will produce solid solution strengthening effect during deposition, which can effectively enhance the mechanical properties of the coating; a part of Si can form amorphous Si3N4, limit grain growth, and refine the grain size, which can further improve the microstructure and mechanical properties of the coating. On the other hand, when the AlCrTiSiN nanocomposite coating is subjected to high temperature oxidation, a thin and dense mixed oxide film (Al2O3, Cr2O3 and SiO2) can be quickly formed on the surface.

[0045] Figure 1 The XRD diffraction spectrum of the AlCrTiSiN nanocomposite coating with nanocrystalline / amorphous composite structure or single amorphous structure prepared by the process of this embodiment can be seen that the AlCrTiSiN nanocomposite coating is mainly in face-centered cubic structure (AlCrTi)N solid solution phase when the Si target power is 50W, and when the Si target power is 50W, a small amount of Si doped into the AlCrTiN coating is mainly in solid solution strengthening effect; another part of Si exists in the coating in the form of amorphous Si3N4, which limits grain growth and refines the grain size, which can further improve the microstructure and mechanical properties of the coating.

[0046] Figure 2 The surface morphology of the AlCrTiSiN nanocomposite coating with nanocrystalline / amorphous composite structure or single amorphous structure prepared by the process of this embodiment is shown in the figure, the coating has small grains and no large particles, and the structure is dense. The surface element composition of the coating is: Al 24.1at.%, Si 3.9at.%, Cr 8.7at.%, Ti 5.9at.% and N 57.1at.%. The hardness of the coating is about 23.95GPa, and the elastic modulus is about 295.36GPa.

[0047] Figure 3 The cross-sectional morphology of the AlCrTiSiN nanocomposite coating with nanocrystalline / amorphous composite structure or single amorphous structure prepared by the process of this embodiment is shown in the figure, the coating is well combined with the substrate, the structure is dense, and the thickness of the coating is about 1.7μm.

[0048] Figure 4 The cross-sectional morphology of the AlCrTiSiN nanocomposite coating with nanocrystalline / amorphous composite structure or single amorphous structure prepared by the process of this embodiment after high temperature oxidation at 900℃ for 6h is shown in the figure, there is a thin and dense mixed oxide film on the surface of the coating, and the thickness of the oxide film is about 370nm.

[0049] Figure 5The cross-sectional morphology of the AlCrTiSiN nanocomposite coating with nanocrystalline / amorphous composite structure or single amorphous structure prepared by the process of the present embodiment after high-temperature oxidation at 1100°C for 6h is shown in FIG. 6. The coating is completely oxidized and consists of oxide particles.

[0050] Example 2

[0051] In the present embodiment, different AlCrTiSiN nanocomposite coatings with nanocrystalline / amorphous composite structure or single amorphous structure were deposited on a single-side polished stainless steel sheet 304. The sample size was 30x30x1mm. 3 The stainless steel sheet 304 was dried after being ultrasonically cleaned in acetone, alcohol and deionized water for 20min. The cleaned sample was then fixed to a rotating frame, and the frame was placed in a furnace and the door was closed. The distance between the target and the sample was 150mm, and the rotating speed of the frame was 15r / min. Two identical AlCrTi alloy targets (atomic ratio of 50:30:20, purity of 99.8%) and a single Si target (purity of 99.99%) were selected. The two AlCrTi alloy targets were connected to a direct current power source, and the Si target was connected to a radio frequency power source. The working gas and the reaction gas were Ar and N2, respectively (gas purity of 99.999%). In the process of depositing the AlCrTiSiN nanocomposite coating in the present embodiment, the target power of the AlCrTi alloy target was 150W, the Si target power was 100W, and the other process parameters were the same as in Example 1.

[0052] Figure 6 The XRD diffraction spectrum of the AlCrTiSiN nanocomposite coating prepared by the process of the present embodiment with nanocrystalline / amorphous composite structure or single amorphous structure is shown in FIG. 5. It can be seen that the AlCrTiSiN nanocomposite coating has no diffraction peak when the Si target power is 100W, and is in an amorphous state.

[0053] Figure 7 The cross-sectional morphology of the AlCrTiSiN nanocomposite coating with nanocrystalline / amorphous composite structure or single amorphous structure prepared by the process of the present embodiment after high-temperature oxidation at 900°C for 6h is shown in FIG. 4. There is a thin and dense mixed oxide film on the surface of the coating, and the thickness of the oxide film is about 330nm.

[0054] Figure 8XRD diffraction spectrum of the AlCrTiSiN nanocomposite coating with nanocrystalline / amorphous composite structure or single amorphous structure prepared by the process of the present embodiment after high-temperature oxidation at 1100°C. It can be seen that the XRD diffraction spectrum of the coating after high-temperature oxidation at 1100°C mainly has fcc-AlN, Al2O3, Cr2O3, TiO2 and SiO2 phases, indicating that the coating forms a protective oxide film at high temperature, and at the same time, the amorphous phase in the coating is converted to face-centered cubic structure AlN phase, and the coating shows good high-temperature oxidation resistance.

[0055] Figure 9 Cross-sectional morphology of the AlCrTiSiN nanocomposite coating with nanocrystalline / amorphous composite structure or single amorphous structure prepared by the process of the present embodiment after high-temperature oxidation at 1100°C for 6h, the coating oxide film is a double-layer structure, and there is still a small amount of coating under the oxide film, and the thickness of the oxide film is about 1.25μm, effectively blocking the inward diffusion of O element.

[0056] The phase structure of the AlCrTiSiN nanocomposite coating prepared by the process of the present embodiment changes obviously, and there is no diffraction peak in the XRD diffraction spectrum, showing amorphous phase; EDS test of the element composition on the surface of the coating is: Al 23.6at.%, Si 6.7at.%, Cr 8.4at.%, Ti 5.5at.% and N 55.5at.%. The hardness of the coating is about 20.10GPa, the elastic modulus is about 222.55GPa, the friction coefficient is 0.6204, and the wear rate is 4.47×10 -6 (mm 3 / N·m). After high-temperature oxidation of the coating at 900°C, there is a thin and dense mixed oxide film on the surface of the coating, and the thickness of the oxide film is 330nm. When the oxidation temperature rises to 1100°C, the coating oxide film is a double-layer structure, and there is still a deposited coating under the oxide film, and the thickness of the oxide film is about 1.25μm.

[0057] Example 3

[0058] This example is to deposit AlCrTiSiN nanocomposite coating with nanocrystalline / amorphous composite structure or single amorphous structure on single-side polished hard alloy YG8, and the sample size is 19 mm x 19 mm x 2 mm. The hard alloy YG8 is dried after being ultrasonically cleaned in acetone, alcohol and deionized water in sequence for 20 min. The cleaned sample is fixed to a rotating frame in sequence, and the rotating frame is placed in a furnace and the furnace door is closed, wherein the distance between the target and the sample is 150 mm, and the rotating speed of the rotating frame is 15 r / min. Two identical AlCrTi alloy targets (atomic ratio of 50:30:20, purity of 99.8%) and a Si target (purity of 99.99%) are selected. The two AlCrTi alloy targets are connected with a direct current power supply, and the Si target is connected with a radio frequency power supply. Ar and N2 (gas purity of 99.999%) are selected as the working gas and the reaction gas, respectively. In this example, the target power of the AlCrTi alloy target is 150 W, the Si target power is 150 W, and the other process parameters are the same as those in Example 1.

[0059] Figure 10 The TEM images of the AlCrTiSiN nanocomposite coating with nanocrystalline / amorphous composite structure or single amorphous structure prepared in the process of this example are shown in (a) bright field image and (b) selected area diffraction ring. The selected area amorphous diffraction ring proves that the coating is amorphous structure.

[0060] Figure 11 The cross-sectional morphology of the AlCrTiSiN nanocomposite coating with nanocrystalline / amorphous composite structure or single amorphous structure prepared in the process of this example after high-temperature oxidation at 900℃ for 6h, there is a thin and dense mixed oxide film on the surface of the coating, and the thickness of the oxide film is about 235 nm.

[0061] Figure 12 The cross-sectional morphology of the AlCrTiSiN nanocomposite coating with nanocrystalline / amorphous composite structure or single amorphous structure prepared in the process of this example after high-temperature oxidation at 1100℃ for 6h, the oxide film of the coating is a double-layer structure, and there is still a small amount of coating under the oxide film, and the thickness of the oxide film is about 1.33 μm, effectively preventing the inward diffusion of O element.

[0062] The AlCrTiSiN nanocomposite coating prepared in the process of this example has the same microstructure and phase structure as the coating in Example 2. The EDS test of the element composition on the surface of the coating is: Al 21.05 at.%, Si 10.56 at.%, Cr 7.47 at.%, Ti 5.00 at.% and N 55.91 at.%. The hardness of the coating is about 20.15 GPa, the elastic modulus is about 233.18 GPa, the friction coefficient is 0.866, and the wear rate is 4.33 x 10 -6(mm 3 TEM tests prove that the coating is amorphous structure. The coating prepared by the process of this embodiment has a thin and dense mixed oxide film on the surface after high temperature oxidation at 900℃, and the thickness of the oxide film is 235 nm. When the oxidation temperature rises to 1100℃, the coating oxide film is a double-layer structure, and there is still a deposited coating under the oxide film, and the thickness of the oxide film is about 1.33 μm. After high temperature oxidation at 900℃, the coating surfaces of this embodiment, embodiment 1 and embodiment 2 all form a thin and dense mixed oxide film, which effectively inhibits further oxidation of the coating. When the oxidation temperature rises to 1100℃, the AlCrTiSiN nanocomposite coating prepared by the process of this embodiment and embodiment 2 is not completely oxidized, and the oxide film is a double-layer structure, and there is still a deposited coating under the oxide film. This is mainly because a large amount of Si in the coating can further reduce the grain size and prolong the diffusion path, thereby effectively inhibiting the outward diffusion of N element and the inward diffusion of O element. This embodiment, embodiment 1 and embodiment 2 all have excellent oxidation resistance after high temperature oxidation at 900℃ for 6h; after high temperature oxidation at 1100℃ for 6h, this embodiment and embodiment 2 are obviously superior to embodiment 1, and have more excellent high temperature oxidation resistance.

Claims

1. An AlCrTiSiN nanocomposite coating having a nanocrystalline / amorphous composite structure or a single amorphous structure, characterized in that: The nano-composite coating is obtained by doping Si into the AlCrTiN coating, and the Si doping amount is 0.1-10.56 at.%; when the Si doping amount is 0.1-4 at%, the nano-composite coating has a face-centered cubic phase and an amorphous phase composite structure, and when the Si doping amount is higher than 4 at%, the nano-composite coating is completely in an amorphous state; The AlCrTiSiN nano-composite coating is deposited on a 304 stainless steel sheet, a single crystal Si sheet or a cemented carbide substrate, and an AlCrTi transition layer is further deposited between the substrate and the AlCrTiSiN nano-composite coating. In the AlCrTiSiN nano-composite coating, the Al content is 21-26 at%, the N content is 55-57 at%, the Cr content is 7-9 at%, the Ti content is 5-6 at%, and the Si content is 0.1-10.56 at%; the sum of the atomic percentages of the elements in the coating is 100%. The AlCrTiSiN nano-composite coating with good high-temperature oxidation resistance and mechanical properties is deposited on a substrate by using a pulse direct current magnetron sputtering and radio frequency direct current magnetron sputtering composite technology; the preparation method of the AlCrTiSiN nano-composite coating specifically comprises the following steps: (1) sequentially fix the to-be-deposited substrate sample on a rotating frame, place the rotating frame in a furnace and close the furnace door, wherein the distance between the target material and the sample is 50-300 mm; (2) using a mechanical pump and a molecular pump to evacuate, until the vacuum degree reaches 5 x 10 -4 The above, open the heating resistance and heat to 200-400℃; when the temperature in the furnace reaches 200-400℃ and the vacuum degree reaches 5 x 10 -4 Pa again, the Ar gas is introduced, the Ar gas flow is set to 30-100sccm, the throttle valve is adjusted to keep the vacuum chamber pressure at 0.8-2Pa, then a bias of -200--800V is applied, and the sample is subjected to glow cleaning, with a cleaning time of 10-30min. (3) after the glow cleaning is completed, adjust the bias voltage to -20-150 V, increase the pressure in the vacuum chamber to 0.3-1 Pa, turn on the direct current power supply, set the target power of the AlCrTi alloy target to 50-200 W, deposit an AlCrTi transition layer, and the deposition time is 10-30 min; (4) keep the target power of the AlCrTi alloy target at 50-200 W and the pressure in the vacuum chamber at 0.3-1 Pa, introduce N2 gas, the N2 gas flow is 10-60 sccm, the N2 / Ar ratio is 1 / 5-3, adjust the bias voltage to -20-150 V, turn on the single-element Si target connected with the radio frequency power supply, the Si target power is 5-150 W, and the deposition time is 120-300 min.

2. The nanocrystalline / amorphous composite structured or single amorphous structured AlCrTiSiN nanocomposite coating according to claim 1, characterized in that: In the nanocomposite coating of the nanocrystal / amorphous composite structure, when Si is doped into the AlCrTiN coating, the solid solution strengthening and fine-grain strengthening effects are dominant, a part of Si is dissolved in the (Al,Cr,Ti)N solid solution phase, and a part forms an amorphous phase Si x N y .

3. The nanocrystalline / amorphous composite structured or single amorphous structured AlCrTiSiN nanocomposite coating according to claim 1, characterized in that: In the pure amorphous AlCrTiSiN nano-composite coating, Si exists in the coating in the form of amorphous Si3N4, which limits the grain growth and promotes the grain size refinement, and can further improve the microstructure and mechanical properties of the composite coating.

4. The nanocrystalline / amorphous composite structured or single amorphous structured AlCrTiSiN nanocomposite coating according to claim 1, characterized in that: The thickness of the AlCrTiSiN nano-composite coating is 1.5-4 μm, and the thickness of the AlCrTi transition layer is 100-300 nm.

5. The nanocrystalline / amorphous composite structured or single amorphous structured AlCrTiSiN nanocomposite coating according to claim 1, characterized in that: The hardness of the AlCrTiSiN nano-composite coating is 20-40 GPa, the elastic modulus is 268-400 GPa, and after the coating is subjected to high-temperature oxidation at 800-1100℃, a continuous and dense oxide film is formed on the surface, which hinders the diffusion of O element and exhibits excellent high-temperature oxidation resistance.

6. The nanocrystalline / amorphous composite or single amorphous structure AlCrTiSiN nanocomposite coating according to claim 1, characterized in that: In step (1), the sample is cleaned before use, and the cleaning process is as follows: sequentially use acetone, alcohol and deionized water for ultrasonic cleaning for 15-30 min, and then dry.

7. The nanocrystalline / amorphous composite or single amorphous structure AlCrTiSiN nanocomposite coating according to claim 1, characterized in that: In the coating preparation, two same AlCrTi alloy targets and one single Si target are selected, the two AlCrTi alloy targets are connected with a direct current power source, and the single Si target is connected with a radio frequency power source; the atomic ratio of Al, Cr and Ti in the AlCrTi alloy target is 50:30:20, and the purity is 99.8%; the purity of the single Si target is 99.99%.

8. The nanocrystalline / amorphous composite or single amorphous structure AlCrTiSiN nanocomposite coating according to claim 1, characterized in that: The thickness of the AlCrTiSiN nano-composite coating is realized by adjusting target power, rotating speed of the rotating stand and deposition time; the Si content in the AlCrTiSiN nano-composite coating gradually increases with the increase of the Si target power.

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