TiSiN / NiTiAlCoCrN anti-cavitation nanomultilayer film and preparation method thereof

Abstract

The application discloses a TiSiN / NiTiAlCrCoN anti-cavitation nanometer multilayer film and a preparation method thereof, and belongs to the technical field of anti-cavitation films. The anti-cavitation film is composed of a transition layer, a periodic multilayer structure and a working layer. The transition layer is located between the substrate and the working layer, and the transition layer is composed of TiN. The periodic multilayer structure is composed of a plurality of modulation period layers, a single modulation period layer is composed of a template layer and a modulation layer, the template layer is composed of NiTiAlCoCrN, and the modulation layer is composed of TiSiN. The working layer is composed of NiTiAlCrCoN. The anti-cavitation film is prepared by using a sputtering method, a TiN layer is deposited on the substrate as the transition layer, then the NiTiAlCoCrN layer and the TiSiN layer are alternately deposited periodically, and finally, the NiTiAlCrCoN working layer is deposited. The application has the characteristics of high bonding strength, high hardness and good anti-cavitation performance, and can be used for the blade surface coating of fluid machinery.

Description

Technical Field

[0001] This invention belongs to the field of anti-cavitation film technology, and relates to a high-entropy alloy nitride nano-multilayer film and its preparation method. It is suitable for surface coating of fluid machinery and can significantly improve the cavitation resistance, corrosion resistance and service life of blades. Background Technology

[0002] Cavitation erosion is one of the main causes of failure in hydraulic components such as steam turbines, turbines, and ship propellers. Cavitation erosion occurs when cavitation bubbles appear near the surface of high-speed rotating blades. The bursting of these bubbles emits microjets and shock waves that repeatedly act on the component's surface, leading to localized microcracks and plastic deformation in the surface material. This results in mass loss, alters the properties and geometry of the component's surface material, and shortens the component's service life. Common methods to improve the cavitation erosion resistance of material surfaces include surface modification, using materials with excellent cavitation erosion resistance, and preparing coatings with good cavitation erosion resistance on the material surface.

[0003] Yan Hongjuan et al. studied the effect of nitrogen-argon flow ratio on the cavitation erosion resistance of NiTiAlCrN coatings (Yan Hongjuan, Liu Yifeng, Mi Zhifeng et al. [J]. Functional Materials, 2023, 54(01):1007-1011+1057.). By changing the ratio of nitrogen to argon, they explored the structure and properties of NiTiAlCrN coatings with different N contents. The microstructure and morphology of the coating material were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. Cavitation erosion experiments were conducted on the coating using an ultrasonic vibration cavitation erosion machine to explore the mechanism of cavitation erosion damage of NiTiAlCrN coatings.

[0004] The existing NiTiAlCrN coating cannot fully meet the requirements of hydraulic components for cavitation resistance, and new coatings need to be developed to improve cavitation resistance. Summary of the Invention

[0005] To improve the cavitation erosion resistance of coatings, this invention provides a high-hardness, cavitation-resistant high-entropy alloy nitride nanolayer film and its preparation method. The high-entropy alloy nitride nanolayer film prepared using this technology can significantly improve the cavitation erosion resistance of blades, reducing the cavitation erosion rate by more than 50%.

[0006] Through extensive research, the inventors discovered that NiTiAlCrCoN high-entropy alloy nitrides possess excellent cavitation erosion resistance, with an erosion rate 10-30% that of 304 stainless steel. Meanwhile, the TiSiN nanocomposite film with a two-phase structure achieves a hardness as high as 40 GPa. By coupling the cavitation erosion resistance and high hardness of NiTiAlCrCoN and TiSiN materials, with the NiTiAlCrCoN layer acting as the cavitation erosion resistance layer and the TiSiN layer enhancing the coating hardness, a TiSiN / NiTiAlCrCoN nanomultilayer film can be prepared, simultaneously improving both coating hardness and cavitation erosion resistance to meet the cavitation erosion resistance requirements of hydraulic components.

[0007] This invention provides a TiSiN / NiTiAlCrCoN nanolayered film with excellent cavitation erosion resistance. The cavitation erosion resistant nanolayered film is characterized by comprising a transition layer, an intermediate layer, and a working layer. The transition layer is located between the substrate and the working layer and is composed of TiN. The intermediate layer consists of several modulation periodic layers, each consisting of a template layer and a modulation layer. The template layer is composed of NiTiAlCoCrN, and the modulation layer is composed of TiSiN. The working layer is composed of NiTiAlCoCrN.

[0008] The working layer NiTiAlCrCoN is a high-entropy alloy nitride with preferred orientations in the (111) and (200) crystal planes. It is mainly composed of nitride phases such as Ni3AlN, CoN, CrAlN, and TiAlN, exhibiting good resistance to cavitation erosion. The intermediate layer periodic structure is formed by the growth of the modulation layer along the template layer lattice structure to form a coherent structure, resulting in a dense columnar crystal structure. An alternating stress field is formed between the interfaces of the intermediate layer structure, enhancing the hardness and toughness of the nanomultilayer film. Furthermore, the modulation layer TiSiN has a two-phase structure where an amorphous phase encapsulates a crystalline phase. By controlling the Si content and distribution, the interface of the two-phase structure of the TiSiN layer is adjusted, and its hardness is controlled to reach 40~50 GPa, ensuring the mechanical properties of the nanomultilayer film. Depositing a TiN transition layer between the substrate and the intermediate layer can improve the bonding strength between the substrate and the nanomultilayer film.

[0009] Furthermore, the total thickness of the anti-cavitation nanolayer film is 1.5~3μm, the thickness of the transition layer is 50~200nm, the thickness of a single modulation period layer is 4~30nm, the thickness of a single template layer is 2~10nm, the thickness of a single modulation layer is 2~20nm, and the thickness of the working layer is 100~200nm.

[0010] Furthermore, the bonding force between the anti-cavitation nanolayer film and the substrate is 17~28N, the hardness is 14~30GPa, and the cavitation rate is 0.04~0.15mg / h.

[0011] This invention also provides a method for preparing the above-mentioned anti-cavitation multilayer film, which uses magnetron sputtering to prepare the film, characterized by comprising the following steps:

[0012] (1) Prepare the target material;

[0013] (2) Matrix pretreatment;

[0014] (3) Install the target and substrate into the sputtering cavity and evacuate the cavity;

[0015] (4) Remove impurities from the surface of the target material;

[0016] (5) Clean the substrate;

[0017] (6) Thin film preparation: N2 is introduced as the reaction gas to maintain a certain vacuum in the cavity; a TiN layer is deposited as a transition layer; then NiTiAlCoCrN layer and TiSiN layer are periodically deposited alternately; finally, a NiTiAlCoCrN layer is deposited.

[0018] (7) Post-deposition treatment: shut off the gas, maintain the vacuum state, and after the substrate cools down, open the cavity and take out the substrate.

[0019] In some specific implementations, the sputtering is magnetron sputtering, and the target material is: Ti target; NiTiAlCoCr alloy target with equimolar ratio of five metal elements Ni, Ti, Al, Co and Cr; TiSi alloy target with Si content between 5 and 20 at.%; step (6) controls the thickness of NiTiAlCoCrN layer and TiSiN layer by controlling the opening and closing time of the target baffles of NiTiAlCoCr target and TiSi target.

[0020] In some specific embodiments, the sputtering is ion plating sputtering;

[0021] Step (6) By controlling the elemental ratio of NiTiAlCoCr target and TiSi target, the atomic ratio of NiTiAlCoCrN layer and TiSiN layer is controlled respectively; by controlling the substrate rotation speed or sputtering time, the thickness of NiTiAlCoCrN layer and TiSiN layer is controlled.

[0022] Furthermore, the purity of the target material is above 99.9%; the substrate pretreatment in step (2) is as follows: the substrate is mirror-finished or polished, ultrasonically cleaned with organic solvent, and then dried; the distance between the target material and the substrate in step (3) is 60~100cm.

[0023] Furthermore, in step (6), the substrate working temperature is controlled between 100 and 400°C; the total thickness of the anti-cavitation multilayer film is controlled to be 1.5 to 3 μm, the thickness of the TiN layer is 50 to 200 nm, the sum of the thicknesses of a single NiTiAlCoCrN layer and a TiSiN layer is 4 to 30 nm, the thickness of a single NiTiAlCoCrN layer is 2 to 10 nm, the thickness of a single TiSiN layer is 2 to 20 nm, and the thickness of the working layer NiTiAlCoCrN layer is 100 to 200 nm.

[0024] In some specific implementation schemes of ion plating sputtering, the removal of impurities on the target surface in step (4) specifically involves: closing the substrate baffle, turning on the bias voltage, turning on the target baffle, and burning the target for several minutes; the cleaning of the substrate in step (5) specifically involves: introducing Ar gas into the cavity to maintain a certain vacuum in the cavity, turning on the bias voltage, and performing glow discharge cleaning on the substrate; after glow discharge cleaning, turning on the ion source under the Ar atmosphere to perform ion cleaning on the substrate.

[0025] The present invention also provides the use of the above-mentioned anti-cavitation nanolayered film, which is used as a surface coating for steam turbine or water turbine blades. Further, the blade substrate is stainless steel or high-speed steel.

[0026] The anti-cavitation erosion nanolayer film provided by this invention has the characteristics of high bonding strength, high hardness, and good anti-cavitation performance, which can solve the problem of blade cavitation erosion and extend the service life of blades. Attached Figure Description

[0027] Figure 1 The process flow diagram for preparing the anti-cavitation multilayer film provided by the present invention is shown.

[0028] Figure 2-5 The images show the cross-sectional morphology of the TiSiN / NiTiAlCrCoN multilayer films obtained in Examples 1-4, respectively. Implementation

[0029] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention. Example 1

[0030] Preparation of anti-cavitation nanolayered films:

[0031] The purity of the Ti target, NiTiAlCoCr target, and TiSi target is 99.9%.

[0032] The substrate is made of mirror-finished stainless steel, which is cleaned with ethanol and acetone in an ultrasonic cleaner and then dried.

[0033] The Ti and NiTiAlCoCr targets are controlled by a DC power supply, while the TiSi target is controlled by an RF power supply with powers of 110W and 200W, respectively. The molar ratios of Ni, Ti, Al, Co, and Cr are equimolar; the atomic ratio of Ti to Si is approximately 9:1. The substrate is mounted on a work stand, the sample stand rotates at 3 rpm, and the substrate temperature is 100℃. Argon and nitrogen flow rates are 9 ml / min, and the total gas pressure is 0.2 Pa. The TiN transition layer thickness is 100 nm; in the multilayer structure, the NiTiAlCoCrN layer thickness is 2 nm, the TiSiN layer thickness is 3 nm, and the modulation period is 5 nm; the NiTiAlCoCrN working layer thickness is 100 nm.

[0034] Characterization of cavitation erosion resistant nanolayered films:

[0035] The cross-sectional morphology of the multilayer film was observed using a Cart Zeiss Sigma-300 scanning electron microscope (SEM), such as... Figure 2 As shown. The hardness of the multilayer film was measured using an Anton Paar UNHT nanoindenter. The indenter was a glass needle tip with a radius of curvature of 100 nm. The maximum load was 4 mN, the loading rate was 20 mN / min, and the unloading rate was 20 mN / min. Five points were randomly selected from each sample, and the average hardness was calculated. The coating adhesion was measured using a WS-2005 automatic coating adhesion scratch tester. The loading rate was 30 N / m, the test load was 30 N, and the scratch length was 3 mm. The cavitation erosion experiment was conducted using an ultrasonic vibration cavitation machine. A 3.5% NaCl solution was selected as the fluid medium. The distance between the coating surface and the top of the vibrating head was 0.5 mm. The diameter of the top of the vibrating head was Φ20 mm. The depth of the sample surface immersed in the fluid medium was (25±5) mm. The temperature was maintained at (25±5) ℃, the power was 1200 W, the frequency was 20 kHz, and the amplitude was 25 μm. The sample was taken out every 2 hours of cavitation erosion and ultrasonically cleaned with anhydrous ethanol. The mass loss was weighed using a HUAZHI electronic balance with an accuracy of 0.1 mg. The total duration of the cavitation erosion experiment was 12 hours.

[0036] The hardness of the anti-cavitation nanolayered film was measured to be 14 GPa, and the adhesion to the substrate was 18 N. Compared with the single-layer film, the number of cavitation pits was significantly reduced, and the cavitation rate was 0.15 mg / h, which is about half the cavitation rate of the single-layer film, effectively improving the anti-cavitation performance. Example 2

[0037] Preparation of anti-cavitation nanolayered films:

[0038] The purity of the Ti target, NiTiAlCoCr target, and TiSi target is 99.9%.

[0039] The substrate is made of high-speed steel. After polishing, it is cleaned with ethanol and acetone in an ultrasonic cleaner and then dried.

[0040] The Ti and NiTiAlCoCr targets are controlled by a DC power supply, while the TiSi target is controlled by an RF power supply with powers of 110W and 200W, respectively. The molar ratios of Ni, Ti, Al, Co, and Cr are equimolar; the atomic ratio of Ti to Si is approximately 9:1. The substrate is mounted on a work stand, the sample stand rotates at 3 rpm, and the substrate temperature is 100℃. The argon gas flow rate is 9 ml / min, the nitrogen gas flow rate is 9 ml / min, and the total gas pressure is 0.2 Pa. The TiN transition layer thickness is 100 nm, the NiTiAlCoCrN layer thickness is 6 nm, the TiSiN layer thickness is 3 nm, and the modulation period is 9 nm; the NiTiAlCoCrN working layer thickness is 100 nm.

[0041] The characterization of the cavitation erosion resistant nanolayered film was the same as in Example 1, and the cross-sectional morphology was as follows. Figure 3 As shown, the hardness of the anti-cavitation nanolayer film is 18 GPa, the bonding force with the substrate is 20 N, there are a few cavitation pits, and the cavitation rate is 0.063 mg / h, which is about one-fifth of the cavitation rate of a single-layer film, effectively improving the anti-cavitation performance. Example 3

[0042] Preparation of anti-cavitation nanolayered films:

[0043] The purity of the Ti target, NiTiAlCoCr target, and TiSi target is 99.9%.

[0044] The substrate is made of high-speed steel. After polishing, it is cleaned with ethanol and acetone in an ultrasonic cleaner and then dried.

[0045] The Ti and NiTiAlCoCr targets are controlled by a DC power supply, while the TiSi target is controlled by an RF power supply with powers of 110W and 200W, respectively. The molar ratios of Ni, Ti, Al, Co, and Cr are equimolar; the atomic ratio of Ti to Si is approximately 9:1. The substrate is mounted on a work stand, the sample stand rotates at 3 rpm, and the substrate temperature is 100℃. The argon gas flow rate is 9 ml / min, the nitrogen gas flow rate is 9 ml / min, and the total gas pressure is 0.2 Pa. The TiN transition layer thickness is 100 nm, the NiTiAlCoCrN layer thickness is 8 nm, the TiSiN layer thickness is 3 nm, and the modulation period is 11 nm; the NiTiAlCoCrN working layer thickness is 100 nm.

[0046] The characterization of the cavitation erosion resistant nanolayered film was the same as in Example 1, and the cross-sectional morphology was as follows. Figure 4As shown, the hardness of the anti-cavitation nanolayer film is 26 GPa, the adhesion to the substrate is 28 N, there are very few cavitation pits, and the cavitation rate is 0.042 mg / h, which is about 14% of the cavitation rate of a single-layer film. This significantly improves the anti-cavitation performance of the film and extends the service life of the substrate. Example 4

[0047] Preparation of anti-cavitation erosion nanolayered films:

[0048] The purity of the Ti target, NiTiAlCoCr target, and TiSi target is 99.9%.

[0049] The substrate is made of high-speed steel. After polishing, it is cleaned with ethanol and acetone in an ultrasonic cleaner and then dried.

[0050] The Ti and NiTiAlCoCr targets are controlled by a DC power supply, while the TiSi target is controlled by an RF power supply with powers of 110W and 200W, respectively. The molar ratios of Ni, Ti, Al, Co, and Cr are equimolar; the atomic ratio of Ti to Si is approximately 9:1. The substrate is mounted on a work stand, the sample stand rotates at 3 rpm, and the substrate temperature is 100℃. The argon gas flow rate is 9 ml / min, the nitrogen gas flow rate is 9 ml / min, and the total gas pressure is 0.3 Pa. The TiN transition layer thickness is 100 nm, the NiTiAlCoCrN layer thickness is 10 nm, the TiSiN layer thickness is 3 nm, and the modulation period is 13 nm; the NiTiAlCoCrN working layer thickness is 100 nm.

[0051] The characterization of the cavitation erosion resistant nanolayered film was the same as in Example 1, and the cross-sectional morphology was as follows. Figure 5 As shown, the hardness of the anti-cavitation nanolayer film is 20 GPa, the bonding force with the substrate is 22 N, there are a few cavitation pits, and the cavitation rate is 0.075 mg / h, which is about 25% of the cavitation rate of a single-layer film, effectively improving the anti-cavitation performance.

[0052] Although embodiments of the present invention have been shown and described above, it is understood that these embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and alterations to the above embodiments within the scope of the present invention without departing from its principles and spirit. The scope of protection of the present invention is defined by the claims and their equivalents.

Claims

1. A TiSiN / NiTiAlCoCrN anti-cavitation nanolayer film, characterized in that, The anti-cavitation erosion nanolayer film consists of a transition layer, an intermediate layer, and a working layer; the transition layer is located between the substrate and the working layer, and the composition of the transition layer is TiN. The intermediate layer consists of several modulation period layers. Each modulation period layer consists of a template layer and a modulation layer. The template layer is composed of NiTiAlCoCrN, and the modulation layer is composed of TiSiN. The working layer is composed of NiTiAlCoCrN. The total thickness of the anti-cavitation nanolayered film is 1.5~3μm, the thickness of the transition layer is 50~200nm, the thickness of a single modulation period layer is 4~30nm, the thickness of a single template layer is 2~10nm, the thickness of a single modulation layer is 2~20nm, and the thickness of the working layer is 100~200nm; the bonding force between the anti-cavitation nanolayered film and the substrate is 17~24N, the hardness is 14~30GPa, and the cavitation rate is 0.04~0.15mg / h.

2. The method for preparing the anti-cavitation erosion nanolayered film according to claim 1, wherein the anti-cavitation erosion nanolayered film is prepared by sputtering, characterized in that, Includes the following steps: (1) Prepare the target material; (2) Matrix pretreatment; (3) Install the target and substrate into the sputtering cavity and evacuate the cavity; (4) Remove impurities from the surface of the target material; (5) Clean the substrate; (6) Thin film preparation: N2 is introduced as the reaction gas to maintain a certain vacuum in the cavity; a TiN layer is deposited as a transition layer; then NiTiAlCoCrN layer and TiSiN layer are periodically deposited alternately; finally, a NiTiAlCoCrN layer is deposited. (7) Post-deposition treatment: shut off the gas, maintain the vacuum state, and after the substrate cools down, open the cavity and take out the substrate.

3. The preparation method according to claim 2, characterized in that, The sputtering is magnetron sputtering; The target material is: Ti target; NiTiAlCoCr alloy target with equimolar ratio of each metal element; TiSi alloy target with Si content between 5 and 20 at.%. Step (6) controls the thickness of the NiTiAlCoCrN layer and the TiSiN layer by controlling the opening and closing time of the target baffles of the NiTiAlCoCr target and the TiSi target.

4. The preparation method according to claim 2, characterized in that, Step (6) By controlling the elemental ratio of NiTiAlCoCr target and TiSi target, the atomic ratio of NiTiAlCoCrN layer and TiSiN layer is controlled respectively; by controlling the substrate rotation speed or sputtering time, the thickness of NiTiAlCoCrN layer and TiSiN layer is controlled.

5. The preparation method according to claim 2, 3, or 4, characterized in that, The purity of the target material is above 99.99%; the substrate pretreatment in step (2) is as follows: the substrate is mirror-finished or polished, ultrasonically cleaned with organic solvent, and then dried; the distance between the target material and the substrate in step (3) is 60~100cm.

6. The preparation method according to claim 2, 3, or 4, characterized in that, In step (6), the substrate working temperature is controlled between 100 and 400°C; the total thickness of the anti-cavitation nanolayer film is controlled to be 1.5 to 3 μm, the thickness of the TiN layer is 50 to 200 nm, the sum of the thicknesses of a single NiTiAlCoCrN layer and a TiSiN layer is 4 to 30 nm, the thickness of a single NiTiAlCoCrN layer is 2 to 10 nm, the thickness of a single TiSiN layer is 2 to 20 nm, and the thickness of the working layer NiTiAlCoCrN layer is 100 to 200 nm.

7. The preparation method according to claim 4, characterized in that, The specific steps for removing impurities from the target surface in step (4) are as follows: close the substrate baffle, turn on the bias voltage, open the target baffle, and burn the target for several minutes. The cleaning of the substrate in step (5) specifically involves: introducing Ar gas into the cavity to maintain a certain vacuum level, turning on the bias voltage, and performing glow discharge cleaning on the substrate; after glow discharge cleaning, turning on the ion source under the Ar atmosphere to perform ion cleaning on the substrate.

8. The use of the anti-cavitation nanolayered film according to claim 1, characterized in that, The anti-cavitation nanolayer film is used as a surface coating for steam turbine or water turbine blades.

9. The use according to claim 8, characterized in that, The blade material is stainless steel or high-speed steel.

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