A method and device for preparing a cathode integrated coating and an AlTiN coating

Abstract

The present invention relates to the technical field of coating preparation, and provides a method and device for preparing a cathode integrated coating and an AlTiN coating. In the present invention, a cathode integrated high-power pulsed magnetron sputtering is carried out on a substrate to obtain a coating; the cathode discharge mode of the cathode integrated high-power pulsed magnetron sputtering is high-current and high-voltage discharge; the peak current of the high-current and high-voltage discharge is 200-2000 A, the peak voltage is 200-2000 V, and the discharge waveform is square. The preparation method provided by the present invention can achieve a high ionization rate and a high deposition rate, and prepare a coating integrating the advantages of AIP and MS; and by using this discharge characteristic, it is easy to adjust the grain size, preferred orientation and phase structure of the coating through parameter adjustment, thereby realizing the adjustment of the hardness and toughness of the coating, greatly improving the coating performance, and at the same time, the coating performance can be adjusted specifically to widen the process window.

Description

Technical Field

[0001] The present invention relates to the technical field of coating preparation, and particularly to a method and device for preparing a cathode integrated coating and an AlTiN coating. Background Art

[0002] PVD tool coatings refer to coatings formed by coating materials on the surface of tools using physical vapor deposition methods (PVD methods), which can improve the hardness, wear resistance, and chemical stability of tools.

[0003] Currently, the PVD technologies used for coating deposition are mainly two types: magnetron sputtering (MS) and arc ion plating (AIP). The traditional arc ion plating technology has the characteristics of high-current discharge, high ionization rate, and high deposition rate. However, in the coatings prepared by this method, there is an easy problem of "large particle" contamination. Large particles refer to neutral particle clusters continuously generated when the arc cathode arc spot rolls and burns on the target surface. These clusters are ejected simultaneously with the plasma and fall onto the surface of the deposited and growing thin film, thus causing surface contamination of the thin film, increasing the roughness of the coating, and reducing the adhesion.

[0004] High Power Impulse Magnetron Sputtering (HiPiMS) can improve the densification of the deposited thin film and the film-substrate bonding force, and avoid the problem of large particle contamination. Although traditional HiPiMS can achieve instant high power and high current, the peak current and peak power cannot achieve continuous discharge, with a low ionization rate and a low deposition rate (the deposition rate is mostly 0.1 - 0.5 μm / H). Summary of the Invention

[0005] In view of this, the present invention provides a method and device for preparing a cathode integrated coating and an AlTiN coating. The cathode integrated coating method provided by the present invention uses a high-current and high-voltage discharge method at the cathode, the discharge waveform is a square waveform, the peak current can be continuously discharged to the ms level, with a high ionization rate and a high deposition rate.

[0006] In order to achieve the above-mentioned invention purposes, the present invention provides the following technical solutions:

[0007] A method for preparing a cathode integrated coating, comprising the following steps:

[0008] Perform cathode integrated high power impulse magnetron sputtering on the substrate to obtain a coating; the cathode discharge method of the cathode integrated high power impulse magnetron sputtering is high-current and high-voltage discharge; the peak current of the high-current and high-voltage discharge is 200 - 2000 A, the peak voltage is 200 - 2000 V, and the discharge waveform is square.

[0009] Preferably, the mode of the integrated cathode high-power pulsed magnetron sputtering is a constant current mode or a constant power mode;

[0010] The conditions of the integrated cathode high-power pulsed magnetron sputtering include: the cathode peak current is 200 - 2000 A, the cathode peak voltage is 200 - 2000 V, the cathode average power is 4 - 40 KW, the cathode pulse frequency is 200 - 3000 Hz, and the cathode duty cycle is 3 - 40%;

[0011] The flow rate ratio of Ar and N2 is 1.4 - 3.5, the chamber pressure is 0.35 - 1 Pa, and the chamber temperature is 500 ± 50 °C;

[0012] The substrate negative bias voltage is -20 - -200 V, the bias power supply frequency is 20 - 50 KHz, and the bias power supply duty cycle is 30% - 90%.

[0013] Preferably, the number of targets for the integrated cathode high-power pulsed magnetron sputtering is 2; the target is an AlTi alloy; and the coating is an AlTiN coating.

[0014] Preferably, the grains of the AlTiN coating are one or more of coarse columnar crystals, fine columnar crystals, and dense crystals;

[0015] The coarse columnar crystal is a columnar crystal with a width of 160 - 200 nm. The crystal phase of the coarse columnar crystal includes c-AlTiN, and the 200 / 111 peak intensity of c-AlTiN in the coarse columnar crystal is less than 1.5;

[0016] The fine columnar crystal is a columnar crystal with a width of 80 - 140 nm. The crystal form of the fine columnar crystal includes c-AlTiN; the 200 / 111 peak intensity of c-AlTiN in the fine columnar crystal is between 1.5 and 4.

[0017] The dense crystal is a columnar crystal with a width of 20 - 60 nm. The crystal form of the dense crystal includes c-AlTiN; the 200 / 111 peak intensity of c-AlTiN in the dense crystal is greater than 4.

[0018] Preferably, when the grains of the AlTiN coating are coarse columnar crystals, the conditions of the integrated cathode high-power pulsed magnetron sputtering for preparing the AlTiN coating include: the cathode peak current is 450 ± 100 A, the cathode peak voltage is 700 ± 50 V, the nitrogen flow rate is 130 ± 5 sccm, and the substrate bias voltage is 40 ± 10 V;

[0019] When the grains of the AlTiN coating are fine columnar crystals, the cathode integrated high-power pulsed magnetron sputtering conditions for preparing the AlTiN coating include: cathode peak current of 600±100A, cathode peak voltage of 720±50V, nitrogen flow rate of 140±5sccm, and substrate bias of 70±10V;

[0020] When the grains of the AlTiN coating are dense crystals, the cathode integrated high-power pulsed magnetron sputtering conditions for preparing the AlTiN coating include: cathode peak current of 750±100A, cathode peak voltage of 750±50V, nitrogen flow rate of 165±5sccm, and substrate bias of 70±10V.

[0021] Preferably, the AlTiN coating comprises a bottom layer and a surface layer; the bottom layer is fine columnar crystals, and the surface layer is dense crystals; the total thickness of the AlTiN coating is 3-10 μm; and the thickness ratio of the surface layer to the bottom layer is 2-6.

[0022] Preferably, before the cathode-integrated high-power pulsed magnetron sputtering is performed, the substrate is further subjected to liquid cleaning, glow cleaning and ion etching;

[0023] The gases used for the glow cleaning are Ar and H2; the conditions for the glow cleaning include: substrate bias voltage is -30 to -90 V, Ar flow rate is 100 to 300 sccm, H2 flow rate is 100 to 300 sccm, Ar to H2 flow ratio is 1.5 to 2.5, and cleaning time is 40 to 60 min;

[0024] The gas used for the ion etching is Ar; the conditions for the ion etching include: Ar flow rate is 200 to 500 sccm, substrate bias voltage is -100 to -300 V, and chamber pressure is 0.8 to 2 Pa.

[0025] The present invention also provides a cathode-integrated magnetron sputtering device used in the method described in the above scheme, comprising a vacuum chamber, a heater, a substrate table, an etching module, a cathode and a cathode power supply, wherein the cathode and the cathode power supply are connected; the cathode power supply is used to control the cathode to perform the high current and high voltage discharge.

[0026] The present invention also provides an AlTiN coating, which is prepared by the method described in the above scheme.

[0027] The present invention also provides the application of the AlTiN coating described in the above solution in a cutting tool.

[0028] The present invention provides a method for preparing a cathode integrated coating, comprising the following steps: performing cathode integrated high-power pulsed magnetron sputtering on a substrate to obtain a coating; the cathode discharge mode of the cathode integrated high-power pulsed magnetron sputtering is high-current and high-voltage discharge; the peak current of the high-current and high-voltage discharge is 200 - 2000 A, the peak voltage is 200 - 2000 V, and the discharge waveform is square. The beneficial effects of the present invention are as follows:

[0029] "Cathode integrated high-power pulsed magnetron sputtering" means continuous discharge on a platform based on traditional HiPiMS. The discharge waveform of traditional HiPiMS is triangular, achieving instant high power and high current, with low ionization rate and low deposition rate; the discharge waveform of "cathode integrated HiPiMS" is square, and the peak current can be continuously discharged to the ms level, with high ionization rate and high deposition rate, and the deposition rate is mostly 0.5 - 5 μm / H. The discharge mode of the present invention combines the high-current discharge characteristics of AIP and the high-voltage discharge characteristics of traditional MS. The prepared coating not only has a smooth surface without droplets, excellent adhesion, fast deposition rate, but also low internal stress.

[0030] Furthermore, the discharge waveform of the traditional HiPiMS technology is triangular, and the peak current and peak power cannot achieve continuous discharge. The total energy of the ionized plasma density is relatively low, and the adjustment of the power supply parameters has limited effect on the total energy adjustment. The high-energy pulse of "cathode integration" can achieve continuous discharge of the peak current and peak power, and the plasma achieves high density and high energy. Using this discharge characteristic, by adjusting the power supply parameters and process parameters, it is easy to adjust the coating grain size, preferred orientation, and phase structure, and further adjust the coating hardness and toughness, greatly improving the coating performance. At the same time, the coating performance can also be adjusted specifically to broaden the process window.

[0031] Taking the AlTiN coating as an example, it is difficult for the traditional HiPiMS technology to accurately adjust the preferred orientation of c-AlTiN and control the c-AlN phase and w-AlN phase. Using the "cathode integrated" HiPiMS technology, it is easier to control the preferred orientation of c-AlTiN. The 200 / 111 peak intensity of c-AlTiN can be adjusted to be less than 1.5, making the coating show relatively thick columnar crystals and better adhesion. It can also be adjusted to make the 200 / 111 peak intensity of c-AlTiN greater than 4, making the coating tend to form dense crystals, with higher density, higher hardness, and wear resistance; using the "cathode integrated" HiPiMS technology can control and avoid the generation of c-AlN phase and w-AlN phase, making the coating have better high-temperature stability and avoid the generation of soft phases, improving the hardness of the coating. Description of the Drawings

[0032] Figure 1Schematic diagram of the structure of the cathode integrated coating device (a) and the cathode discharge waveform diagram (b) adopted by the present invention; Figure 1 Among them: 1 is the first cathode, 1-1 is the first cathode power supply, 2 is the second cathode, 2-2 is the second cathode power supply, 3 is the heater 1 / 2, 4 is the heater 3 / 4, 5 is the heater 5 / 6, 6 is the etching module, 7 is the substrate stage, and 8 is the substrate carrier;

[0033] Figure 2 SEM image of the cross-section of the AlTiN coating obtained in Scheme 1 of Example 1;

[0034] Figure 3 SEM image of the cross-section of the AlTiN coating obtained in Scheme 2 of Example 1;

[0035] Figure 4 SEM image of the cross-section of the AlTiN coating obtained in Scheme 3 of Example 1;

[0036] Figure 5 SEM image of the cross-section of the AlTiN coating obtained in Scheme 4 of Example 1;

[0037] Figure 6 XRD pattern of the AlTiN coatings obtained in Schemes 3, 2, and 5 of Example 1;

[0038] Figure 7 Tool wear comparison diagram of the AlTiN coatings obtained in Schemes 4 and 5 of Example 1 under the turning 316 working conditions;

[0039] Figure 8 SEM image of the surface of the AlTiN coating obtained in Scheme 4 of Example 1. Detailed implementation method

[0040] Glossary: In the present invention, "cathode integrated high-power pulsed magnetron sputtering" refers to a high-power pulsed magnetron sputtering method that simultaneously has high-current (adjustable from 200 to 2000 A) and high-voltage (adjustable from 200 to 2000 V) discharges and can maintain a certain discharge time (from μs to ms).

[0041] The present invention provides a cathode integrated coating preparation method, including the following steps:

[0042] Perform cathode integrated high-power pulsed magnetron sputtering on the substrate to obtain a coating; the cathode discharge mode of the cathode integrated high-power pulsed magnetron sputtering is high-current and high-voltage discharge; the peak current of the high-current and high-voltage discharge is 200 to 2000 A, the peak voltage is 200 to 2000 V, and the discharge waveform is square.

[0043] In the present invention, the deposition rate of the cathode integrated high-power pulsed magnetron sputtering is 0.5 - 5 μm / H; the sustainable discharge time of the peak current can reach the millisecond level, and the maximum can reach 10 ms. In a specific embodiment of the present invention, the sustainable discharge time of the peak current ≤ 10 ms, preferably 0.1 - 10 ms, and more preferably 0.2 - 1 ms.

[0044] In the present invention, the substrate is preferably cemented carbide, specifically cemented carbide blades and square test blocks; the type of the cemented carbide is preferably WC.

[0045] In the present invention, before performing the cathode integrated high-power pulsed magnetron sputtering, it is preferably further included to perform chemical solution cleaning, glow cleaning and ion etching on the substrate; the cleaning agent used for the chemical solution cleaning is preferably a neutral cleaning agent. The present invention has no special requirements for the type of the neutral cleaning agent, and those well-known to those skilled in the art can be used, specifically such as DH-316 and 1102H cleaning agents; the present invention removes glue, oil stains and wax on the substrate surface through chemical solution cleaning; the gas used for the glow cleaning is preferably Ar and H2; the conditions of the glow cleaning preferably include: the substrate bias voltage is -30 to -90 V, preferably -50 to -70 V, the Ar flow rate is 100 to 300 sccm, preferably 150 to 250 sccm, the H2 flow rate is 100 to 300 sccm, preferably 130 to 200 sccm, the flow rate ratio of Ar to H2 is 1.4 to 2.5, the cleaning time is 40 to 60 min, and the chamber pressure is preferably 1 to 2 Pa, more preferably 1.2 Pa; the present invention further removes the oil stains on the substrate surface through glow cleaning; the gas used for the ion etching is preferably Ar; the conditions of the ion etching preferably include: the Ar flow rate is 200 to 500 sccm, preferably 300 to 400 sccm, the substrate bias voltage is -100 to -300 V, preferably -150 to -250 V, and the chamber pressure is 0.8 to 2 Pa, preferably 1 to 1.5 Pa; the present invention continues to clean the stubborn impurities on the substrate surface through ion etching, and at the same time improves the surface roughness of the substrate and enhances the bonding force between the coating and the substrate.

[0046] In a specific embodiment of the present invention, after the chemical solution cleaning is completed, the present invention preferably places the substrate in a vacuum coating machine and evacuates to ≤ 5×10 -3 Pa, then starts the heating module to make the chamber temperature reach the working temperature, the working temperature is preferably 500 ± 50 °C, and then performs glow cleaning under the above conditions. After the glow cleaning is completed, increase the bias voltage to the bias voltage required for ion etching, and turn off H2, only introduce Ar, and perform ion etching under the above conditions.

[0047] After ion etching is completed, the present invention performs cathode-integrated high-power pulsed magnetron sputtering on the substrate after ion etching to obtain a coating on the surface of the substrate. In the present invention, the mode of the cathode-integrated high-power pulsed magnetron sputtering is preferably a constant current mode or a constant power mode; the operating conditions of the cathode-integrated high-power pulsed magnetron sputtering preferably include: the cathode peak current is 200-2000 A, preferably 300-800 A, the peak voltage is 200-2000 V, preferably 300-800 V, the cathode average power is 8-30 KW, preferably 10-25 KW, the cathode pulse frequency is 200-3000 Hz, preferably 250-2000 Hz, the cathode duty cycle is 3-40%, preferably 5-20%; the flow ratio of Ar and N2 is 1.5-3.5, preferably 2-3, the chamber pressure is 0.35-1 Pa, preferably 0.4-0.8 Pa, the chamber temperature is 500±50 °C; the substrate negative bias is -20 to -120 V, preferably -30 to -90 V, the bias power supply frequency is 20-50 KHz, and the bias power supply duty cycle is 30%-90%, preferably 40%-80%.

[0048] In the present invention, the number of targets for the cathode-integrated high-power pulsed magnetron sputtering is preferably 2, and the targets are preferably symmetrically arranged on both sides of the substrate carrier.

[0049] In a specific embodiment of the present invention, the target is preferably an AlTi alloy, and the content of Al in the AlTi alloy is preferably 70 at.%, and the content of Ti is preferably 30 at.%; when the AlTi alloy is used as the target, the coating is an AlTiN coating.

[0050] In the present invention, the cathode-integrated high-power pulsed magnetron sputtering can achieve continuous discharge of peak current and peak power, and the plasma can achieve high density and high energy. By adjusting the power supply parameters and process parameters, it is easy to adjust the coating grain size, preferred orientation and phase structure, thereby greatly improving the coating performance. The following takes the AlTiN coating as an example for specific description.

[0051] In the present invention, the grains of the AlTiN coating are one or more of coarse columnar crystals, fine columnar crystals, and dense crystals; the coarse columnar crystals are columnar crystals with a width of 160 - 200 nm, and the crystal form of the coarse columnar crystals includes c - AlTiN; the intensity of the 200 / 111 peak of c - AlTiN in the coarse columnar crystals is less than 1.5, preferably greater than or equal to 1 and less than 1.5; the fine columnar crystals are columnar crystals with a width of 80 - 140 nm, and the crystal form of the fine columnar crystals includes c - AlTiN; the intensity of the 200 / 111 peak of c - AlTiN in the fine columnar crystals is preferably 1.5 - 4; the dense crystals are columnar crystals with a width of 20 - 60 nm, and the crystal form of the dense crystals includes c - AlTiN; the intensity of the 200 / 111 peak of c - AlTiN in the dense crystals is greater than 4, preferably 4 - 6.

[0052] When the grains of the AlTiN coating are coarse columnar crystals, the conditions for the cathode - integrated high - power pulsed magnetron sputtering for preparing the AlTiN coating preferably include: the cathode peak current is 450 ± 100 A, preferably 450 ± 30 A, the cathode peak voltage is 700 ± 50 V, the nitrogen flow rate is 130 ± 5 sccm, and the substrate bias voltage is 40 ± 10 V.

[0053] When the grains of the AlTiN coating are fine columnar crystals, the conditions for the cathode - integrated high - power pulsed magnetron sputtering for preparing the AlTiN coating preferably include: the cathode peak current is 600 ± 100 A, preferably 600 ± 30 A, the cathode peak voltage is 720 ± 50 V, the nitrogen flow rate is 140 ± 5 sccm, preferably 142 sccm, and the substrate bias voltage is 70 ± 10 V.

[0054] When the grains of the AlTiN coating are dense crystals, the conditions for the cathode - integrated high - power pulsed magnetron sputtering for preparing the AlTiN coating preferably include: the cathode peak current is 750 ± 100 A, preferably 750 ± 30 A, the cathode peak voltage is 750 ± 50 V, the nitrogen flow rate is 165 ± 5 sccm, and the substrate bias voltage is 70 ± 10 V.

[0055] In the present invention, the AlTiN coating preferably includes a bottom layer and a surface layer; the bottom layer is composed of fine columnar crystals, and the surface layer is composed of dense crystals; the total thickness of the AlTiN coating is preferably 3 - 10 μm; the thickness ratio of the surface layer to the bottom layer is preferably 2 - 6, more preferably 3 - 5. In the present invention, the AlTiN coating with fine columnar crystals has a higher bonding strength with the substrate, while the AlTiN coating with dense crystals has a higher hardness. The present invention combines the fine - columnar - crystal bottom layer and the dense - crystal surface layer. The bottom layer can ensure high bonding strength, and the surface layer can increase the hardness of the coating and improve the ability of the coating to resist crack propagation. This combination of the bottom layer and the surface layer is suitable for application scenarios that require high bonding strength and high hardness.

[0056] After the completion of the integrated cathode high-power pulsed magnetron sputtering, degassing is preferably carried out in the present invention; after the coating preparation is completed, there is process gas in the cavity. In the present invention, it is preferred to keep the mechanical pump and the molecular pump running for a period of time to evacuate the process gas and restore the cavity to the body vacuum degree for leak detection of the equipment.

[0057] After the degassing is completed, cooling is preferably carried out in the present invention. After the vacuum coating machine is cooled down to the set temperature (≤200 °C), the coated substrate (i.e., the coated product) can be taken out.

[0058] The present invention also provides an integrated cathode coating device for use in the method described above, including a vacuum chamber, a heater, a substrate stage, an etching module, a cathode, and a cathode power supply. The cathode is connected to the cathode power supply; the cathode power supply is used to control the cathode to perform the high-current and high-voltage discharge.

[0059] In the present invention, the substrate stage is preferably arranged at the central part of the vacuum chamber; a plurality of substrate carriers are arranged on the substrate stage; the substrate carriers are used to place substrates, and multiple substrates can be placed on each substrate carrier to facilitate simultaneous sputtering of multiple substrates.

[0060] In the present invention, the number of heaters is preferably 6, with two as a pair (referred to as a heating module), divided into three pairs of heaters. The three pairs of heaters are preferably arranged evenly around the substrate carrier; in a specific embodiment of the present invention, the three pairs of heaters are respectively denoted as heater 1 / 2, heater 3 / 4, and heater 5 / 6.

[0061] In the present invention, the number of cathodes is preferably 2, and the 2 cathodes are symmetrically arranged on both sides of the substrate carrier; the number of cathode power supplies is preferably 2, and each cathode is connected to a cathode power supply; the cathode includes a back plate and a target arranged on the back plate; in a specific embodiment of the present invention, the two cathodes are respectively denoted as the first cathode and the second cathode, the cathode power supply connected to the first cathode is denoted as the first cathode power supply, and the cathode power supply connected to the second cathode is denoted as the second cathode power supply. In the present invention, the cathode power supply is used to control the cathode to perform the high-current and high-voltage discharge and control the waveform conveniently; the present invention has no special requirements for the cathode power supply, and a commercially available power supply can be used as long as it can realize the high-current and high-voltage discharge of the cathode.

[0062] The present invention has no special requirements for the structure and position of the etching module, and those well-known to those skilled in the art can be used. Specifically, it can be arranged on one side of the substrate carrier.

[0063] The present invention also provides an AlTiN coating, which is prepared by the method described in the above solution; in a specific embodiment of the present invention, the AlTiN coating is preferably a coating with fine columnar crystals at the bottom layer and dense crystals at the surface layer, and its specific thickness and preparation method will not be elaborated here.

[0064] The present invention also provides the application of the AlTiN coating described in the above solution in a tool; in a specific embodiment of the present invention, when applying the AlTiN coating to a tool, the tool can be directly used as a substrate for coating; the present invention has no special requirements for the type of the tool, and those well-known to those skilled in the art can be used. Preparing the AlTiN coating of the present invention on the surface of the tool can effectively improve the hardness and wear resistance of the tool, and the coating has a strong bonding force with the tool substrate.

[0065] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0066] Example 1

[0067] 1. Pretreatment (chemical cleaning): Use a cleaning agent to clean the surface oil and oxides of the substrate, and the substrate is WC cemented carbide.

[0068] 2. Vacuum pumping: Place the substrate in a vacuum coating machine to make the vacuum degree in the vacuum coating machine reach 5×10 -3 Pa.

[0069] 3. Heating: Start the heating module to make the cavity temperature reach the working temperature of 500°C.

[0070] 4. Glow cleaning and ion etching: Pass Ar and H2 under a bias voltage of -60V, where the flow rate of Ar is 200 sccm and the flow rate of H2 is 100 sccm, and perform glow cleaning for 60 min. The main purpose is to remove the oil on the surface of the tool. The flow rate ratio of Ar to H2 is 2, and the chamber pressure is 1.2 Pa. After the glow cleaning is completed, increase the bias voltage, turn off H2, and only pass 300 sccm of Ar. Control the bias voltage to -240 and the chamber pressure to 1.05 Pa to perform ion etching, continue to clean the stubborn impurities on the surface of the substrate tool to be plated, and at the same time improve the surface roughness of the substrate and the bonding force between the coating and the substrate.

[0071] 5. Coating deposition:

[0072] (1) The specific coating equipment and the cathode discharge waveform of the target are shown in Figure 1, during preparation, Cathode1 and 2 are turned on simultaneously, and the two cathode targets work together; the cathode target material used is the AlTi 7030 at.% target material.

[0073] (2) Set the peak current of the coating. In the constant current mode, the peak current and peak voltage are shown in Table 1;

[0074] (3) Set the pulse frequency of the cathode to 600 Hz and the duty cycle to 12%. In the following schemes, the holding time of the peak current is 200 μs;

[0075] (4) The ratio of Ar to N2 is 1.4. The nitrogen flow rate is shown in Table 1, and the chamber pressure is 0.7 Pa.

[0076] (5) The substrate negative bias is shown in Table 1. The frequency of the substrate power supply is 30 KHz and the duty cycle is 80%.

[0077] 6. Degassing: After the coating is completed, there are process gases in the chamber. This step means that after the coating is completed, the mechanical pump is maintained and the molecular pump continues to run for a period of time to pump away the process gases and restore the chamber to the base vacuum for leak detection of the equipment.

[0078] 7. Cooling: Lower the temperature and obtain the coated product. After the coating is completed, cool down the vacuum coating equipment. After it is cooled to the set temperature, take out the coated substrate (finished tool) from the vacuum coating equipment to complete the coating. Test the hardness of the obtained film layer, and the test results are shown in Table 1.

[0079] Table 1: Data table of test parameters

[0080]

[0081]

[0082] Coating detection:

[0083] 1. Cross-section analysis by SEM: Using a scanning electron microscope, magnify the coating cross-section to 10K - 60K to observe the growth morphology of the grain size. The observation results of the coatings obtained in Scheme 1 - Scheme 3 are shown in Figures 2 to 4 ; According to Figures 2 to 4 It can be seen that by setting the process parameters, columnar crystals and dense crystals with adjustable different grain sizes can be prepared. For some usage scenarios that require high bonding strength and high hardness, a combination of fine columnar crystals at the bottom layer and dense crystals on the surface layer (Scheme 4) is preferably recommended. The bottom layer can ensure high bonding strength, and the surface layer increases the hardness of the coating and improves the ability of the coating to resist crack propagation; the observation results of the coating obtained in Scheme 4 are shown in Figure 5 .

[0084] 2. Crystal orientation analysis by XRD: XRD tests were performed on the coatings obtained from Scheme 3 (preferably dense crystals), Scheme 2 (preferably columnar crystals), and Scheme 5 (not recommended). The results are shown in Figure 6 . By comparing the intensities of the (111) and (200) peaks, it is preferably recommended that for the bottom layer, the (200) / (111) peak intensity ratio is between 1.5 and 4, so that the coating presents fine columnar crystals with high bonding strength. For the surface layer, it is preferably that the (200) / (111) peak intensity ratio is greater than 4, and most preferably 4 - 6, so that the coating presents dense columnar crystals with high density and high hardness, and the formation of c-AlN and w-AlN in the coating is controlled to endow the coating with better high-temperature stability and higher hardness.

[0085] 3. Hardness analysis by nanoindentation: A nanoindenter from Anton Paar was used for testing. The indentation depth of the indenter was ≤ 1 / 10 of the coating thickness. 15 points were selected for each sample, and the average value was taken to obtain the coating hardness. The specific test results are shown in Table 1. It can be seen from the test results that in Scheme 5, when c-AlN and w-AlN phases appear in the coating, the coating hardness is the lowest, and the coating hardness of coarse columnar crystals is the second lowest.

[0086] 4. Cutting test: Figure 7 Figure for the tool wear comparison of the coatings obtained from Scheme 4 and Scheme 5 under the turning 316 working conditions. The tool substrate is a cemented carbide turning tool. The specific processing parameters are: Vc = 260 / min, fn = 0.4 mm / min, ap = 1.0 mm, water cooling. It can be seen from the wear comparison figure that the service life of the preferred coating Scheme 4 is 60% or more higher than that of the non-recommended coating Scheme 5, fully indicating that the preferred coating Scheme 4 has better wear resistance.

[0087] 5. SEM test of the coating surface

[0088] Figure 8 SEM image of the surface of the coating obtained from Scheme 4. According to Figure 8 it can be seen that the coating surface is smooth without droplets.

[0089] The results of the above examples show that the cathode integrated coating preparation method provided by the present invention can achieve high ionization rate and high deposition rate, and the deposition rate is mostly 0.5 - 5 μm / H, which is significantly better than traditional HiPiMS; using this discharge characteristic, the adjustment of columnar crystals and dense crystals of the coating can be realized, the adjustment of the (200) and (111) peak intensity ratios of c-AlTiN can be realized, the adjustment of the phase structures of c-AlN and w-AlN can be realized, and the adjustment of the hardness, toughness and bonding strength of the coating can be realized. The coating performance can be adjusted specifically, the process window can be broadened, and the coating performance is greatly improved; in addition, the present invention can prepare a coating integrating the advantages of AIP coatings and MS coatings, that is, it has the characteristics of smooth surface without droplets, high deposition rate, high ionization rate, and low stress.

[0090] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a cathode integrated coating, characterized in that: The following steps are involved: The substrate is subjected to cathode-integrated high-power pulse magnetron sputtering to obtain a coating; the cathode discharge mode of the cathode-integrated high-power pulse magnetron sputtering is to simultaneously discharge high current and high voltage; the discharge waveform of the high current and high voltage discharge is square, and the sustainable discharge time of the peak current is 0.1 to 10 ms; the mode of the cathode-integrated high-power pulse magnetron sputtering is a constant current mode; The conditions of the cathode integrated high-power pulsed magnetron sputtering include: cathode average power of 4-40KW, cathode pulse frequency of 200-3000Hz, cathode duty cycle of 3-40%; Ar and N2 flow ratio of 1.4-3.5, chamber pressure of 0.35-1Pa, chamber temperature of 500±50°C; bias power frequency of 20-50KHz, bias power duty cycle of 30%-90%; The coating is an AlTiN coating; the grains of the AlTiN coating are one or more of coarse columnar crystals, fine columnar crystals and dense crystals; When the grains of the AlTiN coating are coarse columnar crystals, the cathode integrated high-power pulsed magnetron sputtering conditions for preparing the AlTiN coating include: cathode peak current of 450±100A, cathode peak voltage of 700±50V, nitrogen flow rate of 130±5sccm, and substrate bias of 40±10V; When the grains of the AlTiN coating are fine columnar crystals, the cathode integrated high-power pulsed magnetron sputtering conditions for preparing the AlTiN coating include: cathode peak current of 600±100A, cathode peak voltage of 720±50V, nitrogen flow rate of 140±5sccm, and substrate bias of 70±10V; When the grains of the AlTiN coating are dense crystals, the cathode integrated high-power pulsed magnetron sputtering conditions for preparing the AlTiN coating include: cathode peak current of 750±100A, cathode peak voltage of 750±50V, nitrogen flow rate of 165±5sccm, and substrate bias of 70±10V.

2. The preparation method according to claim 1, characterized in that: The number of targets for the cathode-integrated high-power pulsed magnetron sputtering is 2; the target material is AlTi alloy.

3. The preparation method according to claim 2, characterized in that: The coarse columnar crystals are columnar crystals with a width of 160 to 200 nm, the crystal phase of the coarse columnar crystals includes c-AlTiN, and the 200 / 111 peak intensity of c-AlTiN in the coarse columnar crystals is less than 1.5; The fine columnar crystals are columnar crystals with a width of 80 to 140 nm, and the crystal form of the fine columnar crystals includes c-AlTiN; the 200 / 111 peak intensity of c-AlTiN in the fine columnar crystals is between 1.5 and 4; The dense crystal is a columnar crystal with a width of 20 to 60 nm. The crystal type of the dense crystal includes c-AlTiN. The 200 / 111 peak intensity of c-AlTiN in the dense crystal is greater than 4.

4. The preparation method according to claim 1, characterized in that: The AlTiN coating comprises a bottom layer and a surface layer; the bottom layer is fine columnar crystals, and the surface layer is dense crystals; the total thickness of the AlTiN coating is 3-10 μm; and the thickness ratio of the surface layer to the bottom layer is 2-6.

5. The preparation method according to claim 1, characterized in that: Before the cathode integrated high-power pulse magnetron sputtering is performed, the substrate is also subjected to liquid cleaning, glow cleaning and ion etching; The gases used for the glow cleaning are Ar and H2; the conditions for the glow cleaning include: substrate bias voltage of -30 to -90 V, Ar flow rate of 100 to 300 sccm, H2 flow rate of 100 to 300 sccm, Ar to H2 flow rate ratio of 1.5 to 2.5, cleaning time of 40 to 60 min, and chamber pressure of 1 to 2 Pa; The gas used for the ion etching is Ar; the conditions for the ion etching include: Ar flow rate is 200 to 500 sccm, substrate bias voltage is -100 to -300 V, and chamber pressure is 0.8 to 2 Pa.

6. The cathode integrated magnetron sputtering device used in the method according to any one of claims 1 to 5, comprising a vacuum chamber, a heater, a substrate table, an etching module, a cathode and a cathode power supply, wherein the cathode and the cathode power supply are connected; characterized in that: The cathode power supply is used to control the cathode to perform the high current and high voltage discharge.

7. An AlTiN coating, characterized in that: The invention is prepared by the method according to any one of claims 1 to 5.

8. Use of the AlTiN coating according to claim 7 in a cutting tool.

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