AlCrN coating, preparation method thereof and cutter

Abstract

The invention discloses an AlCrN coating, a preparation method of the AlCrN coating and a tool. The preparation method comprises the following process steps that S1, a base body is cleaned; s2, vacuumizing and heating the coating chamber; s3, inert gas and hydrogen are introduced, and the surface of the base body is cleaned and subjected to hydrogen etching; s4, stopping introducing hydrogen, introducing inert gas, and performing lateral ion etching on the surface of the substrate; and S5, two sets of powder metallurgy CrAl targets are started, the content of Cr in the target materials is 40 at.%, the content of Al in the target materials is 60 at.%, inert gas and nitrogen are introduced, the AlCrN coating is prepared through deposition, the substrate bias voltage is 40-180 V, the bias voltage frequency is 10-40 kHz, the bias voltage duty ratio is 50%-90%, the cathode peak power is 5-30 KW, the cathode peak current is 220-600 A, and the cathode pulse width is 80-180 microseconds. According to the preparation method, the AlCrN coating is obtained through parameters of the integrated cathode, the number of liquid drops is effectively reduced, pits in the surface of the coating are reduced, the high-temperature-resistant stability and the oxidation resistance of the coating are improved, and the abrasion resistance and the adhesion resistance of the coated cutting tool are improved.

Description

Technical Field

[0001] The present application relates to the technical field of coating preparation, and particularly relates to an AlCrN coating, a preparation method thereof, and a tool. Background Art

[0002] The AlCrN coating is a multi-element alloy coating developed on the basis of the CrN coating. In it, Al atoms partially replace Cr atoms in the cubic lattice of CrN to form a substitutional solid solution coating. Compared with the CrN coating, due to the solid solution strengthening effect of Al atoms, the AlCrN coating has a hardness higher than 30 GPa. At the same time, the addition of Al atoms enables the coating to generate two dense protective oxides, Al2O3 and Cr2O3, at high temperatures, making it have better wear resistance, high-temperature stability, and oxidation resistance than the CrN coating. Due to these excellent properties, the AlCrN coating is widely used in the field of high-speed cutting, such as finish machining of ball cutters, machining of ordinary die steels under coolant conditions, etc., so as to improve the reliability in the environment of high speed, high temperature, high pressure, heavy load, and corrosive medium during cutting.

[0003] However, the AlCrN coating prepared by cathodic arc ion plating used in current industrial production has many surface "droplets". The appearance of a large number of "droplets" on the surface increases the surface roughness, resulting in an increase in coating defects, and further causing a decline in the mechanical properties of the coating and deterioration of the corrosion resistance and high-temperature resistance, ultimately leading to premature failure of the coating and a reduction in the service life of the tool.

[0004] On the other hand, there are a large number of "droplets" on the surface of the traditional AlCrN coating, and the surface roughness of the coating is relatively large. More "droplets" come into contact with the cutting material, making adhesive wear more likely to occur. The thickness difference between the front and back tool faces of the ball cutter coated with the traditional AlCrN coating is relatively large, resulting in insufficient wear resistance on the front tool face and premature failure of the ball cutter more easily. During the growth process of the traditional AlCrN coating, the crystal orientation is not obvious, the half-height width of diffraction is relatively large, and the degree of crystallization is low. Summary of the Invention

[0005] To solve at least one of the above technical problems, the present application provides an AlCrN coating, a preparation method thereof, and a tool, and the technical solutions adopted are as follows.

[0006] The preparation method of the AlCrN coating provided by the present application includes the following technological steps:

[0007] S1, cleaning the substrate;

[0008] S2, evacuating and heating the coating chamber;

[0009] S3, introducing an inert gas and hydrogen to clean and etch the surface of the substrate with hydrogen;

[0010] S4. Stop introducing hydrogen, introduce an inert gas, and perform lateral ion etching on the surface of the substrate;

[0011] S5. Turn on two groups of powder metallurgy CrAl targets with a Cr content of 40 at.% and an Al content of 60 at.% in the target material. Introduce an inert gas and nitrogen, deposit and prepare an AlCrN coating. The substrate bias voltage is 40 to 180 V, the bias frequency is 10 to 40 kHz, the bias duty cycle is 50% to 90%, the cathode peak power is 5 to 30 KW, the cathode peak current is 220 to 600 A, and the cathode pulse width is 80 to 180 μs.

[0012] In some embodiments of the present application, the cathode peak power is set to 8 to 12 KW, and the cathode peak current is set to 300 to 380 A.

[0013] In some embodiments of the present application, in step S5, the flow rate of the inert gas is 80 to 120 sccm, the flow rate of nitrogen is 150 to 200 sccm, and the pressure in the coating chamber is 0.3 to 1.2 Pa.

[0014] In some embodiments of the present application, in step S5, the pressure in the coating chamber is 0.5 to 0.9 Pa.

[0015] In some embodiments of the present application, in step S5, the substrate bias voltage is set to 60 to 90 V.

[0016] In some embodiments of the present application, in step S5, the bias frequency is set to 10 to 30 kHz.

[0017] In some embodiments of the present application, in step S3, the substrate bias voltage is 30 to 200 V, the pressure in the coating chamber is 1000 to 2000 Pa, the flow rate ratio of the inert gas to hydrogen is 0.5 to 0.8, the filament current is 100 to 300 A, the anode current is 30 to 150 A, and the etching time is 40 to 60 min.

[0018] In some embodiments of the present application, in step S4, the substrate bias voltage is 100 to 300 V, the flow rate of the inert gas is 50 to 300 sccm, the pressure in the coating chamber is 300 to 1200 mPa, the filament current is 100 to 300 A, the anode current is 30 to 150 A, and the etching time is 60 to 100 min.

[0019] The AlCrN coating provided by the present application is obtained by the preparation method described above.

[0020] The surface of the tool provided by the present application is deposited with the AlCrN coating described above.

[0021] The present application has at least the following beneficial effects: The preparation method of the present application obtains the AlCrN coating by using the parameters of the integrated cathode, effectively reducing the number of droplets, reducing the pits on the coating surface, improving the high-temperature stability and oxidation resistance of the coating, and enhancing the wear resistance and anti-adhesion of the coated tool.

[0022] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present application will be further illustrated below with reference to the drawings and embodiments. It should be noted that the embodiments shown in the following drawings are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application.

[0024] Figure 1 It is the SEM surface morphology diagram of the AlCrN coating of the present application.

[0025] Figure 2 It is the SEM surface morphology diagram of the arc AlCrN coating of the comparative example.

[0026] Figure 3 It is the XRD phase analysis diagram of the AlCrN coatings of the present application and the comparative example.

[0027] Figure 4 It is the comparison diagram of the front and back tool faces after milling of the AlCrN coated tool of the present application and the arc AlCrN coated tool. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The following will be combined with Figures 1 to 4 The embodiments of the present application will be described in detail, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application.

[0029] In the description of the present application, it should be understood that if terms such as "center", "middle", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0030] In the description of this application, "several" means more than one, "multiple" means more than two, "greater than", "less than", "exceeding", etc. are understood not to include the recited number, and "above", "below", "within", etc. are understood to include the recited number. If there is a description of "first" and "second", it is only for the purpose of distinguishing technical features and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0031] In the description of this application, unless otherwise clearly specified and limited, the terms "arranged", "installed", "connected", and "coupled" shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0032] In the description of this application, if there are descriptions of reference terms such as "one embodiment", "some embodiments", "one example", "some examples", "some embodiments", "schematic embodiments", "examples", "specific examples", "some examples", etc., it means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0033] This application relates to an AlCrN coating.

[0034] This application relates to a method for preparing an AlCrN coating. The process steps of the preparation method include: cleaning, evacuating, heating, hydrogen etching, lateral ion etching, coating, degassing, and cooling. The specific steps are as follows.

[0035] S1. Clean the substrate.

[0036] S2. Evacuate and heat the coating chamber.

[0037] S3. Introduce inert gas and hydrogen to clean and hydrogen-etch the surface of the substrate.

[0038] S4. Stop introducing hydrogen, introduce inert gas, and perform lateral ion etching on the surface of the substrate.

[0039] In S5, two sets of powder metallurgy CrAl targets are turned on. The Cr content in the target is 40 at.%, and the Al content is 60 at.%. The two targets work simultaneously and are turned on and off at the same time. The vacuum coating machine is set to the constant power mode, and inert gas and nitrogen are introduced to deposit and prepare the AlCrN coating.

[0040] It should be noted that in step S1, the surface of the substrate is cleaned by ultrasonic waves to remove the oil, dust and oxides on the substrate.

[0041] In step S2, the substrate is placed in the coating chamber, and the vacuum degree of the coating chamber does not exceed 50 mPa. The air and impurity gases in the coating chamber are fully evacuated to provide the vacuum environment required for gas discharge in subsequent etching and coating.

[0042] In step S2, the heating module is started to make the temperature of the coating chamber reach 500 °C to 600 °C, evaporating the water vapor on the surface of the coating chamber and the substrate, and heating the substrate sufficiently to provide the required temperature before etching and coating.

[0043] In step S3, the substrate bias voltage is 30 to 200 V, the gas pressure in the coating chamber is 1000 to 2000 Pa, the flow rate ratio of inert gas to hydrogen is 0.5 to 0.8, the filament current is 100 to 300 A, the anode current is 30 to 150 A, and the etching time is 40 to 60 min.

[0044] The inert gas in step S3 is selected as Ar. The surface of the substrate is cleaned by glow discharge argon ions and hydrogen ions to reduce the oxides on the surface of the substrate and activate the surface state.

[0045] In step S4, the substrate bias voltage is 100 to 300 V, the flow rate of inert gas is 50 to 300 sccm, the gas pressure in the coating chamber is 300 to 1200 mPa, the filament current is 100 to 300 A, the anode current is 30 to 150 A, and the etching time is 60 to 100 min.

[0046] The inert gas in step S4 is selected as Ar. The surface of the substrate is bombarded by ions using the characteristics of Ar glow discharge to increase the roughness of the substrate surface and activate the surface state of the substrate, which is beneficial to the subsequent coating adhesion and nucleation growth.

[0047] In step S5, the cathode duty cycle is 50% to 90%, and the cathode pulse width is 80 to 180 μs. The substrate bias voltage is 40 to 180 V. Further, the substrate bias voltage is set to 60 to 90 V.

[0048] In step S5, the bias voltage frequency is 10 to 40 kHz. Further, the bias voltage frequency is set to 10 to 30 kHz.

[0049] In step S5, the cathode peak power is 5 to 30 KW. Further, the cathode peak power is set to 8 to 12 KW.

[0050] In step S5, the cathode peak current is 220 to 600 A. Further, the cathode peak current is set to 300 to 380 A.

[0051] In step S5, the cathode frequency is set to 100 to 1000 Hz.

[0052] In step S5, the inert gas is Ar, the flow rate of the inert gas is 80 to 120 sccm, and the flow rate of nitrogen is 150 to 200 sccm.

[0053] In step S5, the air pressure in the coating chamber is 0.3 to 1.2 Pa. Further, the air pressure in the coating chamber is 0.5 to 0.9 Pa.

[0054] It should be noted that after the coating is completed, turn off the target power supply and the bias power supply, and close the inlet valves of the inert gas and nitrogen. Keep the backing pump and the molecular pump running continuously for 300 to 1000 s, pump down to the body vacuum of the equipment, and check for leaks in the equipment.

[0055] After the coating is completed and the temperature of the coating chamber drops to the set temperature, take out the coated product.

[0056] In the related art, the traditional HiPiMS is smooth and droplet-free, but has a low ionization rate, low deposition efficiency, and poor adhesion. The arc AIP technology has a high ionization rate, high deposition efficiency, and excellent adhesion, but there are many "big droplets" and pit defects on the coating surface. The "integrated cathode" technology adopted in this application is innovatively developed on the basis of both the traditional HiPiMS technology and the arc AIP technology. The "integrated cathode" technology combines the advantages of HiPiMS and AIP, achieving high deposition rate, high ionization rate, and excellent adhesion while making the coating surface smooth and droplet-free.

[0057] The preparation method of this application uses the "integrated cathode" technology to improve the deposition rate of the AlCrN coating, and at the same time makes the coating surface smooth and droplet-free, greatly improving the surface roughness of the coating, preventing adhesive wear, and improving the service life of the AlCrN-coated tool. Through the optimized design of the deposition parameters, control the AlCrN phase structure and preferred orientation, obtain a coating crystal structure with better performance, and improve the mechanical properties of AlCrN.

[0058] The "integrated cathode" has the characteristics of high-current and high-voltage discharge simultaneously and can maintain a certain discharge time. In terms of the discharge mode, it combines the high-current discharge characteristics of AIP and the high-voltage discharge characteristics of traditional MS. The prepared coating not only has excellent adhesion and high deposition rate, but also there is no "molten pool" generated by high-temperature arc discharge on the target surface, avoiding the generation of "large droplets". Therefore, the coating surface presents the characteristics of smoothness and no droplets. By designing and optimizing the process parameters of the "integrated cathode", the performance of the AlCrN coating is regulated. Finally, an AlCrN coating with a smooth and droplet-free surface can be prepared, reducing coating defects and significantly improving the service life of the tool.

[0059] Combined with the attached Figure 1 and the attached Figure 2 , a scanning electron microscope (SEM) is used to observe the "droplet" situation on the coating surface. In this application, by setting the "integrated cathode" parameters, the number of "droplets" on the coating surface is controlled. While the surface of the arc AlCrN coating as a comparative example has more "droplets" and pits.

[0060] Combined with the attached Figure 3 , an X-ray diffractometer is used to detect and analyze the crystal structure of the coating, observing the peak intensity and the full width at half maximum of the peaks at different angles of 36.96°, 42.99° and 63.95°. The coating prepared in this application has better high-temperature stability and oxidation resistance.

[0061] Combined with the attached Figure 4 , a ball cutter is used to finish machine 45# simultaneously, and the rake face and flank face are observed after 120 minutes. Compared with the AlCrN coating tool of the comparative example, the coating tool of this application has a more complete rake face, and the wear resistance and anti-adhesion of the rake face are better.

[0062] According to the above analysis, it can be seen that in this application, the surface of the AlCrN coating prepared by the "integrated cathode" is smooth and droplet-free, overcoming the problem of easy adhesion of the rake face of the ball cutter, showing the advantages of better wear resistance and anti-bonding.

[0063] Compared with the AlCrN coating of the comparative example, the 111 / 200 of the AlCrN coating prepared in this application is larger, the 111 crystal plane grows preferentially, the crystal orientation is better, and the diffraction peak intensity is higher, the full width at half maximum is smaller, the grain size is smaller, the strength and hardness of the coating are higher, and it has better flexural strength and smaller lattice distortion and other advantages.

[0064] The above has described the embodiments of the present application in detail in conjunction with the accompanying drawings. However, the present application is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art in the technical field, various changes can be made without departing from the purpose of the present application. In addition, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

Claims

1. A preparation method of an AlCrN coating, characterized in that: Including S1, cleaning the substrate; S2, evacuating and heating the coating chamber; S3, introducing inert gas and hydrogen, and cleaning and hydrogen etching the surface of the substrate; S4, stopping introducing hydrogen, introducing inert gas, and performing lateral ion etching on the surface of the substrate; S5, turning on two sets of powder metallurgy CrAl targets with 40 at.% Cr content and 60 at.% Al content in the target material, introducing inert gas and nitrogen, depositing to prepare an AlCrN coating, with the substrate bias voltage being 40 to 180 V, the bias frequency being 10 to 40 kHz, the bias duty cycle being 50% to 90%, the cathode peak power being 5 to 30 KW, the cathode peak current being 220 to 600 A, and the cathode pulse width being 80 to 180 μs.

2. The preparation method of the AlCrN coating according to claim 1, characterized in that: The cathode peak power is set to 8 to 12 KW, and the cathode peak current is set to 300 to 380 A.

3. The preparation method of the AlCrN coating according to claim 1, wherein: In step S5, the flow rate of the inert gas is 80 to 120 sccm, the flow rate of nitrogen is 150 to 200 sccm, and the air pressure in the coating chamber is 0.3 to 1.2 Pa.

4. The preparation method of the AlCrN coating according to claim 3, characterized in that: In step S5, the air pressure in the coating chamber is 0.5 to 0.9 Pa.

5. The preparation method of the AlCrN coating according to claim 1, characterized in that: In step S5, the substrate bias voltage is set to 60 to 90 V.

6. The preparation method of the AlCrN coating according to claim 1, characterized in that: In step S5, the bias frequency is set to 10 to 30 kHz.

7. The preparation method of the AlCrN coating according to claim 1, characterized in that: In step S3, the substrate bias voltage is 30 to 200 V, the air pressure in the coating chamber is 1000 to 2000 Pa, the flow rate ratio of the inert gas to hydrogen is 0.5 to 0.8, the filament current is 100 to 300 A, the anode current is 30 to 150 A, and the etching time is 40 to 60 min.

8. The preparation method of the AlCrN coating according to claim 1, characterized in that: In step S4, the substrate bias voltage is 100 to 300 V, the flow rate of the inert gas is 50 to 300 sccm, the air pressure in the coating chamber is 300 to 1200 mPa, the filament current is 100 to 300 A, the anode current is 30 to 150 A, and the etching time is 60 to 100 min.

9. An AlCrN coating, characterized in that: The AlCrN coating is obtained by using the preparation method described in any one of claims 1 to 8.

10. A cutting tool, characterized in that: The surface of the tool is deposited with the AlCrN coating described in claim 9.

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