A method for preparing an alti n composite coating and a coated cutting tool

Abstract

The application provides a preparation method of an AlTiN composite coating and a coated cutter, and belongs to the technical field of cutter blade coating. The application first performs first arc ion plating of a TiN transition layer on the surface of a base body, so as to improve the bonding force between the base body and the AlTiN coating, then performs second arc ion plating of an AlTiN coating, and controls the target current of the second arc ion plating, so as to enable the (200) preferred orientation of the crystal face structure of the AlTiN coating, the target material has a suitable melting speed and a relatively uniform melting, the droplet content is reduced, the droplet peeling and crack generation in the use process are avoided, the coating peeling is avoided, and the service life of the base body is improved. The wear loss of the coating prepared by the preparation method is less than or equal to 0.143 mm after milling for 15 min, the wear loss is less than or equal to 0.185 mm after milling for 30 min, and the wear loss is less than or equal to 0.225 mm after milling for 45 min.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of milling blade coating, and particularly relates to a preparation method of AlTiN composite coating and coated cutting tool. BACKGROUND

[0002] 304 stainless steel is widely used in industry due to its good corrosion resistance, heat resistance, low temperature strength and other characteristics. However, due to its excellent plasticity and low thermal conductivity, etc., there is a serious sticking and work hardening phenomenon during processing, which is one of the typical difficult-to-machine materials in industry. During the milling process of 304 stainless steel, the cutting edge of the milling blade and the machining material will produce built-up edge, which will cause the local temperature between the cutting tool and the machining material to rise, resulting in the interdiffusion of elements between the hard alloy milling blade and the machining material, and reducing the performance of the substrate blade. In order to ensure the performance of the blade, a coating is usually deposited on the surface of the cutting tool for protection.

[0003] The AlTiN coating, as an optimized tool coating from TiN, has been widely used due to its excellent hardness and high temperature stability. The Al element in the coating forms a dense Al2O3 oxide layer under high temperature service conditions, which can effectively increase the oxidation resistance of the coating. At the same time, the generated Al2O3 oxide layer can further reduce the thermal conductivity of the coating, so that the interdiffusion phenomenon between the cutting tool and the workpiece interface during processing is reduced. Therefore, the AlTiN coating is widely used in dry cutting field, and the milling objects are mainly 304 and 316L stainless steel materials, and it is also applied in high temperature alloy, die steel, 45 steel and other fields.

[0004] At present, AlTiN coating is usually prepared by arc ion plating, but the AlTiN coating prepared by arc ion plating has a surface defect (droplet). The peeling of the droplet exposes the substrate material in advance during milling, and the cracks generated during processing will grow with the notch, which will cause the coating to peel off in advance and reduce the service life of the milling blade. At the same time, the poor adhesion between the coating and the substrate is also a key factor affecting the service life. Therefore, it is very meaningful to explore a preparation method that can improve the adhesion of the coating and reduce the surface droplet of the coating. SUMMARY

[0005] The present application provides a preparation method of AlTiN composite coating and coated cutting tool. The AlTiN composite coating prepared by the preparation method provided by the present application has good adhesion with the substrate, less surface defects (droplets), preferred orientation (200) of crystal face, small wear amount, and can effectively improve the service life of the cutting tool.

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

[0007] The application provides a preparation method of an AlTiN composite coating, comprising the following steps:

[0008] (1) performing first arc ion plating on a surface of a substrate to obtain a TiN transition layer;

[0009] (2) performing second arc ion plating on the surface of the TiN transition layer obtained in the step (1) to obtain an AlTiN composite coating;

[0010] The target current of the second arc ion plating is 120-160 A.

[0011] Preferably, the target current of the first arc ion plating in the step (1) is 90-150 A, and the substrate bias voltage of the first arc ion plating is -600 to -1000 V.

[0012] Preferably, the time of the first arc ion plating in the step (1) is 2-5 min.

[0013] Preferably, the cavity pressure of the first arc ion plating in the step (1) is 3-5 Pa.

[0014] Preferably, the atomic percentage of Ti in the TiN transition layer in the step (1) is 40-60%.

[0015] Preferably, the second arc ion plating in the step (2) is performed in four stages; the substrate bias voltages of the four stages are -40 to -140 V, -45 to -145 V, -50 to -150 V and -60 to 160 V in sequence; and the substrate bias voltages of the four stages increase in sequence.

[0016] Preferably, the atomic percentages of Al, Ti and N in the AlTiN coating in the step (2) are 30-40%, 10-20% and 40-60% respectively.

[0017] Preferably, the thickness of the AlTiN coating in the step (2) is 0.8-1.5 μm.

[0018] The application further provides a coated tool bit comprising a blade substrate and an AlTiN composite coating prepared by the preparation method.

[0019] Preferably, the model of the blade substrate comprises one of APMT1135, APMT1604, RPMT1003 and RDMW1204.

[0020] This invention provides a method for preparing an AlTiN composite coating, comprising the following steps: (1) performing a first arc ion plating on the substrate surface to obtain a TiN transition layer; (2) performing a second arc ion plating on the surface of the TiN transition layer obtained in step (1) to obtain an AlTiN composite coating; the target current of the second arc ion plating is 120-160A. This invention first performs a first arc ion plating on the substrate surface to obtain a TiN transition layer, improving the adhesion between the substrate and the AlTiN coating. Then, a second arc ion plating is performed to form an AlTiN coating on the surface of the TiN transition layer, resulting in an AlTiN composite coating. By controlling the target current of the second arc ion plating, the AlTiN coating has a preferred orientation of a (200) crystal plane structure, improving the coating's service life. Simultaneously, the target material has a suitable melting rate and relatively uniform melting, reducing the dripping content and preventing coating peeling due to dripping and cracking during use, further improving the substrate's service life. The results of the embodiments show that the wear amount of the coating prepared by the preparation method provided by the present invention is less than 0.143 mm after milling for 15 minutes, less than 0.185 mm after milling for 30 minutes, and less than 0.225 mm after milling for 45 minutes. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the AlTiN composite coating prepared according to the present invention, wherein 1 is the AlTiN coating, 2 is the TiN transition layer, and 3 is the substrate;

[0022] Figure 2 This is a SEM image of the AlTiN composite coating prepared in Example 1 of the present invention;

[0023] Figure 3 This is a SEM image of the AlTiN composite coating prepared in Example 2 of the present invention;

[0024] Figure 4 This is a SEM image of the AlTiN composite coating prepared in Example 3 of the present invention;

[0025] Figure 5 Here is a SEM image of the AlTiN composite coating prepared in Comparative Example 1 of this invention;

[0026] Figure 6 The images show the XRD patterns of the AlTiN composite coatings prepared in Examples 1-3 and Comparative Example 1 of this invention. Detailed Implementation

[0027] This invention provides a method for preparing an AlTiN composite coating, comprising the following steps:

[0028] (1) A first arc ion plating is performed on the substrate surface to obtain a TiN transition layer;

[0029] (2) performing second arc ion plating on the surface of the TiN transition layer obtained in step (1) to obtain an AlTiN composite coating.

[0030] The application performs first arc ion plating on the surface of the substrate to obtain a TiN transition layer.

[0031] In the application, the substrate is preferably cemented carbide.

[0032] In the application, the substrate is preferably subjected to sand blasting, acid pickling, alkali pickling, ultrapure water cleaning and drying in sequence before use.

[0033] In the application, the time for sand blasting is preferably 2-4 s, more preferably 3 s; and the pressure during sand blasting is preferably 0.1-0.3 MPa, more preferably 0.2 MPa.

[0034] In the application, the pickling solution for acid pickling is preferably SYTQX acid cleaner; and the time for acid pickling is preferably 10-20 min.

[0035] In the application, the pickling solution for alkali pickling is preferably SYTHB alkali cleaner; and the time for alkali pickling is preferably 10-20 min.

[0036] In the application, the time for ultrapure water cleaning is preferably 10-20 min.

[0037] In the application, the acid pickling, alkali pickling and ultrapure water cleaning are preferably performed under ultrasonic conditions. The application does not have special limitations on the power of the ultrasonic, and any ultrasonic power known to those skilled in the art can be used.

[0038] In the application, the sand blasting, acid pickling, alkali pickling and ultrapure water ultrasonic cleaning are used to remove impurities on the surface of the substrate.

[0039] In the application, the temperature for drying is preferably 80-100℃. The application does not have special limitations on the time for drying, and the time for drying only needs to ensure that the substrate is completely dried.

[0040] In the application, the target for the first arc ion plating is preferably a Ti target; and the purity of the Ti target is preferably 99.99%. In the application, the first arc ion plating is preferably performed under a nitrogen atmosphere; and the channel flow rate of the nitrogen is preferably 300-500 sccm, more preferably 350-450 sccm, and further preferably 400 sccm. In the application, during the first arc ion plating, Ti is ionized from the Ti target, and N is ionized from the nitrogen, and the two combine to form a TiN transition layer; the TiN transition layer has moderate hardness and plays a transition role, which can reduce the internal stress of the substrate and the AlTiN coating and improve the bonding force of the substrate and the AlTiN coating.

[0041] In the application, the target current of the first arc ion plating is preferably 90-150 A, more preferably 110-140 A; the substrate bias voltage of the first arc ion plating is preferably -600 to -1000 V, more preferably -700 to -900 V, and further preferably -800 V; the cavity pressure of the first arc ion plating is preferably 3-5 Pa, and more preferably 4 Pa; and the time of the first arc ion plating is preferably 2-5 min, and more preferably 3-4 min. By limiting the parameters of the first arc ion plating within the above ranges, the TiN transition layer is more uniform and has a suitable thickness, and the adhesion between the substrate and the AlTiN coating is further improved.

[0042] In the application, the atomic percentage of Ti in the TiN transition layer is preferably 40-60%, more preferably 45-55%, and further preferably 50%.

[0043] In the application, the first arc ion plating preferably includes bombarding cleaning of the substrate and cleaning and activation of the target material; the bombarding cleaning of the substrate and the cleaning and activation of the target material preferably include: placing the substrate on a rotating support, the support being located in a vacuum coating chamber, and the Ti target and the AlTi target also being located in the vacuum coating chamber, adjusting the basic cavity pressure of the vacuum chamber to 0.5*10 -3 Pa-1.5*10 -3 Pa by a vacuum pump, heating the cavity temperature to 450-550℃ for 20-40 min, rotating the speed of the rotating support at 3-4 r / min, and introducing nitrogen and argon in a volume ratio of (1-3):1, and arc ionizing Ar + to the substrate under a bias voltage of -800 to -900 V for 5-20 min; closing the nitrogen channel, maintaining the bias voltage of -800 to -900 V, opening the hydrogen channel (hydrogen flow rate is 30 sccm) to ionize H + to the surface of the target material for 5-10 min. In the application, the bombarding cleaning of the substrate and the cleaning and activation of the target material can remove impurities on the surface of the substrate and ensure the ionization rate of the target material in the subsequent arc process.

[0044] After obtaining the TiN transition layer, the application performs second arc ion plating on the surface of the TiN transition layer to obtain an AlTiN composite coating.

[0045] In the present application, the target of the second arc ion plating is preferably an AlTi target; the atomic percentage of Al and Ti in the AlTi target is preferably 2:1. In the present application, the second arc ion plating is preferably carried out in a nitrogen atmosphere; the channel flow of the nitrogen is preferably 300-500 sccm, more preferably 350-450 sccm, and further preferably 400 sccm. In the present application, during the second arc ion plating, Al and Ti are ionized from the AlTi target by arc, and N is ionized from the nitrogen, and the three combine to form an AlTiN coating.

[0046] In the present application, the target current of the second arc ion plating is 120-160 A, preferably 130-150 A, and more preferably 140 A; the second arc ion plating is preferably carried out in four stages; the substrate bias of the four stages is preferably -40 to -140 V, -45 to -145 V, -50 to -150 V, and -60 to -160 V, and more preferably -60 to -120 V, -65 to -125 V, -70 to -130 V, and -75 to -135 V, in sequence; the substrate bias of the four stages preferably increases in sequence; the time of the four stages is preferably 15-25 min, 35-45 min, 60-70 min, and 60-80 min, respectively; the cavity pressure of the second arc ion plating is preferably 2-6 Pa, and more preferably 3-5 Pa; the temperature of the second arc ion plating is preferably 400-550℃, and more preferably 450-500℃; the present application controls the target current of the second arc ion plating, which can make the AlTiN coating have a preferred orientation of (200) crystal face structure, improve the service life of the coating, and at the same time, the target material has a suitable melting speed and uniform melting, reduces the droplet content, avoids the peeling and cracking of the droplet in the use process, causes the coating to fall off, and further improves the service life of the substrate; the second arc ion plating is carried out in four stages, and the substrate bias gradually increases, which makes the AlTiN coating form a gradient structure, the content of Al and Ti changes in the thickness direction, the Al content at the bottom is low, has good affinity with the TiN transition layer, can eliminate the voids at the joint of the TiN transition layer and the AlTiN coating, enhances the bonding strength of the TiN transition layer and the AlTiN coating, improves the anti-peeling ability of the AlTiN coating, the top has a high Al content, makes the AlTiN coating have good hardness and oxidation resistance, good wear resistance, reduces the wear amount of the coating, and further improves the service life of the coating.

[0047] In the present application, the atomic percentage of Al, Ti, and N in the AlTiN coating is preferably 30-40%, 10-20%, and 40-60%, respectively.

[0048] In the present application, the thickness of the AlTiN coating is preferably 0.8-1.5 μm, more preferably 0.9-1.2 μm.

[0049] The present application first performs first arc ion plating on the surface of the substrate to obtain a TiN transition layer, improves the adhesion between the substrate and the AlTiN coating, then performs second arc ion plating to obtain an AlTiN composite coating, controls the target current of the second arc ion plating to make the AlTiN coating have a preferred orientation of (200) crystal face structure, improves the service life of the coating, at the same time, the target material has a suitable melting speed and the melting is relatively uniform, reduces the droplet content, avoids the peeling of droplets and the generation of cracks in the use process, and leads to the peeling of the coating. The second arc ion plating is performed in four stages and the substrate bias is gradually increased, so that the AlTiN coating forms a gradient structure, and the service life of the substrate is further improved.

[0050] The AlTiN composite coating provided by the present application has the structure as shown in Figure 1 preferably, wherein 1 is the AlTiN coating, 2 is the TiN transition layer, and 3 is the substrate.

[0051] The present application also provides a coated tool including a blade substrate and an AlTiN composite coating prepared by the preparation method described above.

[0052] In the present application, the AlTiN coating preferably has a composition gradient.

[0053] In the present application, the model of the blade substrate preferably includes one of APMT1135, APMT1604, RPMT1003 and RDMW1204.

[0054] The coated tool provided by the present application has better adhesion between the blade substrate and the coating, better wear resistance, and longer service life.

[0055] The technical solutions in the present application will be clearly and completely described below in combination with the embodiments in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0056] Example 1

[0057] (1) The hard alloy milling tool insert substrate (APMT1604, COM-10, Kunshan Changying Hard Alloy Factory) was sandblasted to remove various impurities on the surface, the sandblasting time was 3 s, the pressure was 0.2 Mpa, and after sandblasting, the substrate was placed in an ultrasonic water tank for acid washing, alkali washing and ultrapure water washing for 15 min each, the residual liquid was blown off, and the substrate was dried in an oven at 90°C for 60 min and then sent to an arc ion plating chamber, placed on a rotating support, and a Ti target (purity 99.99%) and an AlTi target (atomic percentage of Al and Ti 2:1, purity 99.99%) were also placed in the arc ion plating chamber. The basic cavity pressure of the vacuum chamber was adjusted to 1.0 x 10 -3 Pa by a vacuum pump, the chamber temperature was heated to 550°C for 30 min, the rotating support was rotated at a speed of 3.5 r / min, N2 and Ar were first introduced at a volume ratio of 2:1, and Ar + was ionized by arc ionization, the substrate was bombarded and cleaned for 15 min at a bias voltage of -800 V, the N2 channel was closed, the bias voltage was maintained at -800 V, the H2 channel (flow rate 30 sccm) was opened, and H + was ionized. The surface of the target material was cleaned and activated for 8 min.

[0058] (2) The H2 channel was closed, the N2 channel was opened, the channel flow rate was 400 sccm, the cavity pressure in the furnace was 3 Pa, the Ti target was powered on, the target current was 120 A, and a TiN transition layer with a thickness of about 0.1 μm was deposited on the substrate surface at a substrate bias voltage of -800 V for 5 min.

[0059] (3) The AlTi target was powered on, the target current was 120 A, the deposition temperature was 550°C, the cavity pressure was 2 Pa, and the substrate bias voltage was -40 V (20 min), -45 V (40 min), -50 V (65 min), and -60 V (65 min) in four stages. An AlTiN gradient coating was prepared on the surface of the TiN coating, the deposition time was 190 min, and the thickness was 0.9 μm.

[0060] Example 2

[0061] In example 2, the target current in step (3) of example 1 was replaced with 130 A, and the other parameters were the same as in example 1, to obtain an AlTiN gradient coating with a thickness of about 1.1 μm.

[0062] Example 3

[0063] (1) The same as example 1;

[0064] (2) Close the H2 channel and open the N2 channel. The channel flow rate is 400 sccm, the furnace cavity pressure is 3 Pa, and the Ti target is energized with a target current of 140 A and a substrate bias voltage of -800 V. Deposit a TiN transition layer on the substrate surface for 5 min with a thickness of about 0.1 μm.

[0065] (3) The AlTi target was energized with a target current of 130A, a deposition temperature of 550℃, a cavity pressure of 2Pa, and a substrate bias of -100V (20min), -105V (40min), -110V (65min), and -120V (65min) in four stages to prepare an AlTiN gradient coating on the TiN coating surface. The deposition time was 190min and the thickness was 1.0μm.

[0066] Comparative Example 1

[0067] (1) Same as Example 1;

[0068] (2) Close the H2 channel and open the N2 channel. The channel flow rate is 400 sccm, the furnace cavity pressure is 3 Pa, and the Ti target is energized with a target current of 140 A and a substrate bias voltage of -800 V. Deposit a TiN transition layer on the substrate surface for 5 min with a thickness of about 0.1 μm.

[0069] (3) The AlTi target was energized with a target current of 180A, a deposition temperature of 550℃, a cavity pressure of 2Pa, and a substrate bias of four stages: -40V (20min), -45V (40min), -50V (65min), and -60V (65min) to prepare an AlTiN gradient coating on the TiN coating surface. The deposition time was 190min and the thickness was 1.5μm.

[0070] The coatings prepared in Examples 1-3 and Comparative Example 1 were observed using scanning electron microscopy, and the obtained SEM images are shown below. Figures 2 to 5 As shown. From Figures 2 to 5 As can be seen, the droplet density on the surface of the coatings prepared in Examples 1 to 3 is smaller than that in Comparative Example 1. The droplet density and the size of a single droplet on the surface of the coating in Example 3 are both smaller than those in the other examples, indicating that the present invention can effectively reduce surface defects (droplets) of the coating by adjusting the target current.

[0071] The XRD patterns of the coatings prepared in Examples 1-3 and Comparative Example 1 are shown below. Figure 6 As shown. From Figure 6 As can be seen from the data, the AlTiN coatings of Examples 1-3 and Comparative Example 1 are mainly composed of solid solution AlTiN phase. The (200) coating structure of Example 3 has the most obvious preferred orientation, indicating that the present invention can make the (200) preferred orientation of the AlTiN coating crystal structure by adjusting the target current.

[0072] The coated tools prepared in Examples 1-3 and Comparative Example 1 were used to mill 304 stainless steel in dry milling mode at a spindle speed of 1500 r / min, a feed speed of 270 mm / min, a feed per pass of 0.5 mm, and no cooling liquid. The flank wear was measured every 15 min, and the results are shown in Table 1.

[0073] Table 1 Flank wear test results for Examples 1-3 and Comparative Example 1

[0074]

[0075]

[0076] As shown in Table 1, the service life of the coated tools of Examples 1-3 was greatly improved compared to Comparative Example 1. The surface droplets were minimized, and the flank wear of Example 3, which had a preferred (200) crystal plane structure, was the lowest.

[0077] In summary, by controlling the target current of the second arc ion plating, the AlTiN coating has a preferred (200) crystal plane structure, which improves the service life of the coating. The target material has a suitable melting speed and uniform melting, which reduces the droplet content, avoids droplet peeling and cracking during use, and prevents the coating from falling off, thereby further improving the service life of the substrate.

[0078] The above description is only preferred embodiments of the present application, and it should be pointed out that, for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should also be considered as the protection scope of the present application.

Claims

1. A method for preparing an AlTiN composite coating, comprising the following steps: (1) performing first arc ion plating on the surface of a substrate to obtain a TiN transition layer: the target material for the first arc ion plating is a Ti target, the first arc ion plating is performed in a nitrogen atmosphere, the channel flow rate of the nitrogen is 400 sccm, the internal cavity pressure of the furnace is 3 Pa, the Ti target is powered, the target current is 140 A, the substrate bias is -800 V, the TiN transition layer is deposited on the surface of the substrate for 5 min, and the thickness is 0.1 μm; (2) performing second arc ion plating on the surface of the TiN transition layer obtained in the step (1) to obtain an AlTiN composite coating: the AlTi target is powered, the target current is 130 A, the deposition temperature is 550 ℃, the cavity pressure is 2 Pa, the second arc ion plating is performed in four stages, the substrate bias of the four stages is increased in turn, the substrate bias of the four stages is -100 V, -105 V, -110 V and -120 V respectively, the time of the four stages is 20 min, 40 min, 65 min and 65 min respectively, the AlTiN gradient coating is prepared on the surface of the TiN coating, the deposition time is 190 min, and the thickness is 1.0 μm.

2. A coated cutting tool, comprising a blade substrate and an AlTiN composite coating prepared by the method of claim 1; the AlTiN composite coating comprises a TiN transition layer and an AlTiN coating deposited on the surface of the TiN transition layer.

3. The coated cutting tool of claim 2, wherein, The model of the blade substrate comprises one of APMT1135, APMT1604, RPMT1003 and RDMW1204.

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