CrTiN superhard nanomultilayer film and preparation method thereof

Abstract

The application relates to the technical field of thin film preparation, in particular to a CrTiN superhard nanometer multilayer thin film and a preparation method thereof, which comprises a substrate and a nanometer composite coating deposited on the surface of the substrate; the nanometer composite coating comprises a Cr bonding layer covering the substrate, and a CrN / TiN nanometer composite layer covering the Cr bonding layer; the thin film provided by the application combines the excellent performances of CrN and TiN, the CrN and TiN layers are alternately deposited to form a superhard multilayer structure, and the multilayer design not only improves the mechanical performance of the coating, but also significantly improves the oxidation resistance, corrosion resistance and wear resistance of the coating.

Description

Technical Field

[0001] This invention relates to the field of thin film preparation technology, specifically to a CrTiN ultrahard nanomultilayer thin film and its preparation method. Background Technology

[0002] In recent years, with the rapid development of machining, mold manufacturing, aerospace and other fields, the requirements for material surface properties have been increasing. Hard films can improve the wear resistance, corrosion resistance and high-temperature stability of materials, and are used in related fields. Traditional single-component hard films, such as TiN and CrN films, are no longer sufficient to meet the increasingly demanding working conditions. Therefore, developing a novel method for preparing CrTiN ultrahard nanolayered films to meet the high performance requirements of industrial applications has significant practical importance and broad market prospects. To overcome this problem, multilayer coating technology has emerged, combining the advantages of different materials to prepare coatings with better overall performance. Cathodic arc technology is a physical vapor deposition (PVD) process that uses a high-energy electric arc to evaporate the target material into ionized metal and form a reaction layer in a gaseous environment. Multilayer CrN / TiN coatings prepared by cathodic arc technology have attracted much attention due to their ultrahardness, high wear resistance and excellent oxidation resistance.

[0003] In the preparation of CrTiN coatings, cathodic arc technology enables efficient ionization and rapid deposition of the target material, ensuring the density and uniformity of the coating. However, the plasma generated by traditional cathodic arc technology contains a large number of micro-droplets (large particles), which reduces the density and surface smoothness of the film, affecting the final performance. To address this, magnetic filtration technology has been introduced in existing technologies to remove large particles. However, ordinary magnetic filtration devices are often simple in structure, have limited filtration efficiency, and lack optimized design and precise control of key parameters (such as magnetic field configuration, number of coil turns, deflection angle, etc.), resulting in blurred film interfaces, poor structural consistency, and unstable performance improvement. Nanoscale multilayer films, by alternately depositing two or more different materials to form a periodic structure, can effectively improve the comprehensive properties of the film, such as hardness, wear resistance, and oxidation resistance. Among many nanoscale multilayer film systems, the CrTiN system has attracted much attention due to its excellent mechanical properties and chemical stability. CrN has good wear resistance and corrosion resistance, while TiN has high hardness and good toughness. By alternating deposition of CrN and TiN at nanoscale thicknesses, periodically modulated CrTiN ultrahard nanolayered films possessing the advantages of both can be obtained. However, existing methods for preparing CrTiN nanolayered films still have some shortcomings. Traditional methods struggle to precisely control the thickness and interface structure of each layer, leading to blurred interfaces and affecting film performance. Summary of the Invention

[0004] To address the above problems, the purpose of this invention is to provide a CrTiN ultrahard nanolayered thin film and its preparation method. By alternately depositing CrN and TiN layers, a nanoscale multilayer structure is formed. The prepared film has high hardness and strong adhesion, which can effectively improve the lifespan of cutting tools, molds, and other components, and enhance their service reliability. The technical solution adopted by this invention is as follows:

[0005] A CrTiN ultrahard nanomultilayer film includes a substrate and a nanocomposite coating deposited on the surface of the substrate.

[0006] The nanocomposite coating includes a Cr bonding layer covering the substrate and a CrN / TiN nanocomposite layer covering the Cr bonding layer.

[0007] A further technical solution is that the substrate is made of titanium alloy, stainless steel or bearing steel; the CrN / TiN nanocomposite layer is formed by alternating layers of CrN and TiN, and has a periodically modulated amorphous structure.

[0008] A further technical solution is that the thickness of the Cr bonding layer is 50nm-150nm; and the thickness of the CrN / TiN nanocomposite layer is 0.5μm-1.5μm.

[0009] A method for preparing CrTiN ultrahard nanolayered thin films, comprising the following steps:

[0010] S1. Sputter cleaning: After surface polishing, ultrasonic cleaning with acetone and ethanol, and drying, the plated sample is placed on the rotatable plated sample holder of the coating equipment. The vacuum is drawn to 5.0×10-3Pa, argon gas is introduced, the bias power supply is started, and Ar plasma glow discharge sputter cleaning is performed on the sample with a bias voltage of -800V to remove oxides and impurities on the sample surface. The time is 10-15min.

[0011] S2. Introduce argon gas at 50 or 100 sccm, adjust the bias voltage to -75V, adjust the Cr target current to 120A, and use a columnar cathode magnetic filter system to filter the Cr plasma. The angle between the axial centerline of the curved pipe of the magnetic filter system and the normal of the target surface and the center of the plating fixture is 125°, and the number of turns of its filter coil is 127. The current of the magnetic filter coil near the target is set to 85A, and the current of the magnetic filter coil near the cavity is set to 70A. Deposit a Cr bonding layer on the substrate surface for 15-30 minutes.

[0012] S3. Depositing CrN / TiN nanocomposite layer: Based on step S2, introduce nitrogen gas at 50-100 sccm, adjust the Cr target current to 160A, turn on the Ti target, and adjust the current to 160A. Both the Cr target and the Ti target are equipped with the same columnar cathode magnetic filter system described above. The two magnetic filter cathodes are symmetrically arranged with the rotating plating fixture as the center. The plating fixture revolves and rotates. The CrN / TiN nanocomposite layer is deposited by arc through the magnetic filter cathode for 45-60 minutes, forming a periodic modulation structure. S4. Turn off the power. The coating preparation is complete. After cooling to room temperature, open the cavity and take samples.

[0013] A further technical solution is that the flow rate of argon and nitrogen is 50-100 sccm, and the working pressure is 0.3-0.5 Pa.

[0014] A further technical solution is that the Cr and Ti targets are both pure metal targets with a purity of 99.9%; and the argon and nitrogen gases both have a purity of 99.999%.

[0015] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0016] 1. The thin film provided by the present invention combines the excellent properties of CrN and TiN. By using magnetic filtering cathode arc technology with specific optimized parameters to alternately deposit CrN and TiN layers, an ultra-hard multilayer structure is formed.

[0017] 2. The multi-layer design not only improves the mechanical properties of the coating, but also significantly enhances its oxidation resistance, corrosion resistance and wear resistance.

[0018] 3. The preparation method of this invention, particularly the use of a 125° filtration angle, a 127-turn coil, and a symmetrically arranged magnetic filtration system, can yield a CrTiN ultrahard nanolayered film with high hardness and good wear resistance. This film has a nanoscale multilayer structure, which effectively improves the film's hardness and wear resistance.

[0019] 4. The preparation method of the present invention is simple and low in cost, and is suitable for large-scale industrial production.

[0020] 5. By optimizing process parameters, this invention enables CrN / TiN multilayer films to have better stability under high temperature conditions and extends the service life of the coating. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the CrTiN ultrahard nanomultilayer film of the present invention.

[0022] Figure 2This is a SEM cross-section of the CrN / TiN periodic modulation structure of the present invention; the modulation period of the multilayer film can be seen from this figure.

[0023] Figure 3 These are the nanoindentation test results of the coatings in Examples 1 and 2 of this invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] Example 1:

[0026] refer to Figures 1 to 3 As shown, a CrTiN ultrahard nano-multilayer thin film is disclosed, comprising a substrate and a nanocomposite coating deposited on the surface of the substrate; the nanocomposite coating comprises a Cr bonding layer covering the substrate and a CrN / TiN nanocomposite layer covering the Cr bonding layer.

[0027] The substrate is made of titanium alloy, stainless steel or bearing steel; the CrN / TiN nanocomposite layer is formed by alternating layers of CrN and TiN, and has a periodically modulated amorphous structure.

[0028] The thickness of the Cr bonding layer is 50nm-150nm; the thickness of the CrN / TiN nanocomposite layer is 0.5μm-1.5μm.

[0029] The thin film provided by this invention combines the excellent properties of CrN and TiN. By employing an optimized magnetic filtration technique with alternating deposition of CrN and TiN layers using a cathodic arc, an ultra-hard multilayer structure is formed. This multilayer design not only enhances the mechanical properties of the coating but also significantly improves its oxidation resistance, corrosion resistance, and wear resistance.

[0030] This paper provides a method for preparing CrTiN ultrahard nanolayered thin films, which includes the following steps:

[0031] S1. Sputter cleaning: After surface polishing, ultrasonic cleaning with acetone and ethanol, and drying, the plated sample is placed on the rotatable plated sample holder of the coating equipment. The vacuum is drawn to 5.0×10-3Pa, argon gas is introduced, the bias power supply is started, and Ar plasma glow discharge sputter cleaning is performed on the sample with a bias voltage of -800V to remove oxides and impurities on the sample surface. The time is 10-15min.

[0032] S2. Introduce 100 sccm of argon gas, adjust the bias voltage to -75V, adjust the Cr target current to 120A, and use a columnar cathode magnetic filter system to filter the Cr plasma. The angle between the axial centerline of the curved pipe of the magnetic filter system and the normal of the target surface and the center of the plating fixture is 125°, and the number of turns of its filter coil is 127. The current of the magnetic filter coil near the target is set to 85A, and the current of the magnetic filter coil near the cavity is set to 70A. Deposit a Cr bonding layer on the substrate surface for 15-30 minutes.

[0033] S3. Plating CrN / TiN nanocomposite layer: Based on step S2, nitrogen gas is introduced at 50-100 sccm, the Cr target current is adjusted to 160A, the Ti target is turned on, and the current is adjusted to 160A. Both the Cr target and the Ti target are equipped with the same columnar cathode magnetic filter system described above. The two magnetic filter cathodes are symmetrically arranged with the rotating plating fixture as the center. The plating fixture revolves around and rotates on its own axis. The CrN / TiN nanocomposite layer is deposited by arc through the magnetic filter cathode for 45-60 minutes, forming a periodic modulation structure.

[0034] S4. Turn off the power. The coating preparation is complete. After cooling to room temperature, open the cavity and take a sample.

[0035] Specifically, it includes the following:

[0036] 1. After surface polishing, ultrasonic cleaning with acetone and ethanol, and drying, the sample to be plated (substrate material) is placed on the rotatable workpiece holder of the coating equipment (magnetic filter cathode arc deposition equipment). The vacuum is drawn to 5.0×10-3Pa, Ar is introduced, the bias power supply is started, and a bias voltage of -800V is applied to the sample for Ar plasma glow sputtering cleaning to remove oxides and impurities on the sample surface for 15 minutes.

[0037] 2. Cr bonding layer deposition: Argon gas is introduced at 100 sccm, and the bias voltage is adjusted to -75V. A cylindrical magnetic filter cathode with a 125° deflection angle and 127 turns of coil is used to filter the Cr plasma. The Cr target current is adjusted to 120A. The workpiece fixture is rotated and revolved. The current of the magnetic filter coil near the target is set to 85A, and the current of the magnetic filter coil near the cavity is set to 70A. A Cr bonding layer is deposited on the substrate surface for 30 minutes.

[0038] 3. Deposition of CrN / TiN nanocomposite layer: Based on step 2, nitrogen gas is introduced at 100 sccm, the Cr target current is adjusted to 160 A, the Ti target is turned on, and the current is adjusted to 160 A. The magnetic filter cathode structure parameters of the Cr target and the Ti target are the same (125°, 127 turns), and they are symmetrically arranged with the workpiece tooling as the center. The CrN / TiN nanocomposite layer is deposited by magnetic filter cathode arc deposition for 60 min.

[0039] 4. Turn off the power. The coating preparation is complete. After cooling to room temperature, open the cavity and take a sample.

[0040] The above embodiments demonstrate the fabrication of a CrTiN ultrahard nanolayered film with a nanohardness of 46.8 GPa. In practical applications, parameters such as the number of layers and the thickness of each layer can be adjusted as needed to obtain the required film performance.

[0041] Example 2:

[0042] The difference between Implementation 2 and Example 1 is that the nitrogen flow rate in step 3 of Example 1 is adjusted to 50 sccm, while maintaining the same deposition time. The other steps are the same as in Example 1.

[0043] A method for preparing CrTiN ultrahard nanolayered thin films is as follows:

[0044] 1. After surface polishing, ultrasonic cleaning with acetone and ethanol, and drying, the sample to be plated (substrate material) is placed on the rotatable workpiece holder of the coating equipment (magnetic filter cathode arc deposition equipment). The vacuum is drawn to 5.0×10-3Pa, Ar is introduced, the bias power supply is started, and a bias voltage of -800V is applied to the sample for Ar plasma glow sputtering cleaning to remove oxides and impurities on the sample surface for 15 minutes.

[0045] 2. Cr bonding layer deposition: Argon gas is introduced at 100 sccm, the bias voltage is adjusted to -75V, the Cr target current is adjusted to 120A, and a columnar magnetic filter cathode with a 125° deflection angle and 127 turns of coil is used to filter the Cr plasma. The magnetic filter coil current near the target is set to 85A, and the magnetic filter coil current near the cavity is set to 70A. A Cr bonding layer is deposited on the substrate surface for 30 minutes.

[0046] 3. CrN / TiN nanocomposite layer deposition: Based on step 2, nitrogen gas is introduced at 50 sccm, the Cr target current is adjusted to 160 A, the Ti target is turned on, and the current is adjusted to 160 A. The magnetic filter cathode structure parameters of the Cr target and the Ti target are the same (125°, 127 turns), and they are symmetrically arranged with the plating fixture as the center. The plating fixture revolves and rotates, and the CrN / TiN nanocomposite layer is deposited by magnetic filter cathode arc deposition for 60 min.

[0047] 4. Turn off the power. The coating preparation is complete. After cooling to room temperature, open the cavity and take a sample.

[0048] Through the above embodiments, a CrTiN ultrahard nanomultilayer film with a nanohardness of 31.7 GPa can be prepared. In practical applications, parameters such as the number of layers and the thickness of each layer can be adjusted as needed to obtain the required film properties.

[0049] In Examples 1 and 2, the flow rates of argon and nitrogen were 50-100 sccm, the working pressure was 0.3-0.5 Pa, the Cr and Ti targets were pure metal targets with a purity of 99.9%, and the purity of argon and nitrogen was 99.999%.

[0050] Although the invention has been described herein with reference to several illustrative embodiments, it should be understood that many other modifications and implementations can be devised by those skilled in the art, which will fall within the scope and spirit of the principles disclosed herein. More specifically, various variations and modifications can be made to the components and / or layout of the subject matter arrangement within the scope of the disclosure, drawings, and claims. Besides variations and modifications to the components and / or layout, other uses will be apparent to those skilled in the art.

Claims

1. A CrTiN ultrahard nanolayered thin film, characterized in that: It includes a substrate and a nanocomposite coating deposited on the surface of the substrate; the nanocomposite coating includes a Cr bonding layer covering the substrate and a CrN / TiN nanocomposite layer covering the Cr bonding layer.

2. The CrTiN ultrahard nanolayered thin film according to claim 1, characterized in that: The substrate is made of titanium alloy, stainless steel or bearing steel; the CrN / TiN nanocomposite layer is formed by alternating layers of CrN and TiN, and has a periodically modulated amorphous structure.

3. The CrTiN ultrahard nanolayered thin film according to claim 1, characterized in that: The thickness of the Cr bonding layer is 50nm-150nm; the thickness of the CrN / TiN nanocomposite layer is 0.5μm-1.5μm.

4. A method for preparing a CrTiN ultrahard nanolayered thin film as described in any one of claims 1-3, characterized in that, The magnetically filtered cathode arc deposition method includes the following steps: S1, sputtering cleaning: After surface polishing, ultrasonic cleaning with acetone and ethanol, and drying, the sample is placed on the rotatable workpiece holder of the coating equipment. A vacuum of 5.0 × 10⁻³ Pa is applied, argon gas is introduced, and the bias power supply is started. An Ar plasma glow discharge sputtering cleaning is performed on the sample with a bias voltage of -800V to remove oxides and impurities from the sample surface for 10-15 minutes; S2, 50 or 100 sccm of argon gas is introduced, the bias voltage is adjusted to -75V, the Cr target current is adjusted to 120A, and a columnar cathode magnetic filter system is used to filter the Cr plasma. The angle between the axial centerline of the curved pipe of the magnetic filter system and the normal to the target surface and the center of the workpiece fixture is 125°, and the filter coil has 127 turns, close to the target. The magnetic filter coil current is set to 85A, and the magnetic filter coil current near the cavity is set to 70A. A Cr bonding layer is deposited on the substrate surface for 15-30 minutes. S3, CrN / TiN nanocomposite layer plating: Based on step S2, nitrogen gas is introduced at 50-100 sccm, the Cr target current is adjusted to 160A, and the Ti target current is turned on and adjusted to 160A. The Cr target and Ti target are equipped with the same columnar cathode magnetic filter system with identical structural parameters. The two magnetic filter cathodes are symmetrically arranged with the rotating plating fixture as the center. The plating fixture revolves and rotates. The CrN / TiN nanocomposite layer is deposited by electric arc through the magnetic filter cathode for 45-60 minutes, forming a periodic modulation structure. S4, The power is turned off, the coating preparation is completed, and the cavity is opened for sampling after cooling to room temperature.

5. The method for preparing a CrTiN superhard nanolayered thin film according to claim 4, characterized in that: The flow rates of argon and nitrogen are 50-100 sccm, and the working pressure is 0.3-0.5 Pa.

6. The method for preparing a CrTiN superhard nanolayered thin film according to claim 4, characterized in that: The Cr and Ti targets are both pure metal targets with a purity of 99.9%; the argon and nitrogen gases both have a purity of 99.999%.

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