Composite coating as well as preparation method and application thereof

Abstract

The invention discloses a composite coating as well as a preparation method and application thereof, and relates to the technical field of coatings. The composite coating comprises a CrN layer, an AlCrN layer, a ZrAlCrN layer, a ZrCrCN layer and a CrCN layer which are sequentially arranged in a stacked mode. And the CrCN layer is a surface layer. The obtained composite coating has the advantages of high hardness, high bonding strength, high wear resistance and high adhesive wear resistance, is good in oxidation resistance and is suitable for being used as a cutter coating, when a prepared cutter is used for cutting titanium alloy, the condition of tipping or adhesive wear is not prone to occurring, and the service life of the cutter is remarkably prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to a composite coating and a preparation method and application thereof. Background Art

[0002] Titanium alloy has low density (the density of pure titanium is only 4.5g / cm 3 ), and features high strength and wear resistance, making it widely used in aerospace, biomedical, and consumer electronics applications. However, during titanium alloy machining, due to the high chemical affinity between the cutting tool and the titanium alloy, a "like dissolves like" phenomenon easily occurs. Under the action of force and heat, adhesive wear and even tool breakage are very likely to occur, resulting in reduced tool life and increased machining costs.

[0003] In order to overcome this defect, coatings are currently used to enhance the wear resistance or anti-adhesion performance of cutting tools during titanium alloy cutting. Typical titanium alloy cutting tool coatings include TiAlN, CrAlN, ZrN, TiAlZrN, etc. Among them, although CrAlN and TiAlN have good wear resistance and oxidation resistance, their anti-adhesion ability is poor and they cannot take into account both wear resistance and anti-adhesion effects. Although ZrN has a certain friction reduction effect, its wear resistance and anti-adhesion performance need to be improved. TiAlZrN is Zr doped in TiAlN, but a single layer of TiAlZrN is still unable to resist adhesive wear during titanium alloy cutting, and there are still problems of short tool life and severe tool sticking. Summary of the Invention

[0004] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art. To this end, the present invention aims to provide a composite coating that improves both the wear resistance and anti-adhesion properties of the composite coating by designing the coating composition and combining different coatings.

[0005] A second aspect of the present invention is to provide a method for preparing a composite coating.

[0006] A third aspect of the present invention is to provide a cutting tool.

[0007] A fourth aspect of the present invention provides an application of a cutting tool.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A first aspect of the present invention provides a composite coating, comprising a CrN layer, an AlCrN layer, a ZrAlCrN layer, a ZrCrCN layer and a CrCN layer stacked in sequence; the CrCN layer is a surface layer.

[0010] The present invention provides a composite coating that utilizes C and Zr doping to form CrCN, ZrCrCN, and ZrAlCrN layers. These coatings can function as anti-friction layers, reducing the composite coating's coefficient of friction, improving its wear resistance, and enhancing its resistance to adhesive wear. Furthermore, the composite coating includes AlCrN and CrN layers, which serve as support for the anti-friction layer, enhancing its wear resistance and oxidation resistance, thereby increasing the durability of the composite coating and, in turn, the service life of the product protected by the composite coating.

[0011] In some embodiments, the composite coating has a thickness of 2 to 4 μm.

[0012] In some embodiments, the CrN layer, the AlCrN layer, and the ZrAlCrN layer each independently include at least two coating layers.

[0013] Specifically, "comprising at least two layers" means comprising at least a transition layer and a functional layer. For example, a CrN layer comprises a CrN transition layer and a CrN functional layer; a ZrAlCrN layer comprises a ZrAlCrN transition layer and a ZrAlCrN functional layer, wherein the ZrAlCrN layer can be expressed as a ZrAlCrN layer or an AlZrCrN layer; an AlCrN layer comprises an AlCrN transition layer and an AlCrN functional layer. In some specific embodiments, the AlCrN layer can be expressed as a CrAlN layer or an AlCrN layer, for example, the CrAlN transition layer and the AlCrN functional layer both belong to the AlCrN layer; wherein the AlCrN functional layer is a nano-multilayer structure, specifically 9 to 11 layers. The provision of the transition layer helps to reduce the internal stress between layers and improve the bonding strength between layers.

[0014] During the fabrication of various layers among these CrN, AlCrN, and ZrAlCrN layers, the process parameters for the transition layer and the functional layer may be the same or different. In some embodiments, the transition layer is deposited using a gradient process, including a gradient target current, a gradient substrate bias voltage, or a gradient gas flow rate, while the functional layer is deposited under constant parameters.

[0015] The second aspect of the present invention provides a method for preparing the composite coating according to the first aspect of the present invention, comprising the following steps:

[0016] A CrN layer, an AlCrN layer, a ZrAlCrN layer, a ZrCrCN layer and a CrCN layer are sequentially deposited on the substrate to obtain the composite coating.

[0017] In some embodiments, the preparation method comprises the following steps:

[0018] A CrN transition layer, a CrN functional layer, an AlCrN transition layer, an AlCrN functional layer, a ZrAlCrN functional layer, a ZrAlCrN transition layer, a ZrAlCrN functional layer, a ZrCrCN transition layer and a CrCN layer are sequentially deposited on the substrate to obtain the composite coating.

[0019] Specifically, the AlCrN functional layer is deposited in a multi-layer mode to form a nano-multilayer AlCrN functional layer with 9 to 11 layers.

[0020] In some embodiments, the depositing comprises the following steps:

[0021] The Cr target current was set to gradually change from 90 to 110 A to 150 to 180 A to deposit the CrN transition layer; the Cr target current was set to 150 to 180 A to deposit the CrN functional layer;

[0022] The Cr target current was set to gradually change from 150-180A to 90-130A, and the Al target current was set to gradually change from 90-110A to 150-180A to deposit the AlCrN transition layer; the Cr target current was set to 90-130A, and the Al target current was set to 150-180A to deposit the AlCrN functional layer;

[0023] The Cr target current is set to 90-130A, the Al target current is 150-180A, and the Zr target current is 110-150A to deposit the ZrAlCrN functional layer; the Cr target current is set to 90-130A, the Al target current is gradually changed from 150-180A to 110-140A, and the Zr target current is gradually changed from 110-150A to 150-180A to deposit the ZrAlCrN transition layer; the Cr target current is set to 90-130A, the Al target current is 110-140A, and the Zr target current is 150-180A to deposit the ZrAlCrN functional layer;

[0024] The Cr target current was set to gradually change from 90-130A to 150-180A, and the Zr target current was set to gradually change from 150-180A to 110-150A to deposit the ZrCrCN transition layer;

[0025] The Cr target current was set to 150-180 A to deposit the CrCN layer.

[0026] In some embodiments, the deposition time is 5 to 20 minutes. It should be understood that the deposition time here refers to the deposition time of each layer being 5 to 20 minutes.

[0027] In some embodiments, during the deposition process, the substrate bias voltage is set to -30 to -120 V; the substrate bias voltage is a gradual or constant type.

[0028] In some embodiments, during the deposition process, the flow rate of argon gas is 10 to 550 scm.

[0029] In some specific embodiments, when depositing the CrN transition layer, the nitrogen flow rate is gradually changed from 200 to 300 sccm to 400 to 500 sccm; the substrate bias voltage is gradually changed from -90 to -120 V to -50 to -70 V; and the deposition time is 2 to 10 minutes.

[0030] In some specific embodiments, when depositing the CrN functional layer, the nitrogen flow rate is 400-500 sccm, the substrate bias voltage is constant at -50-70 V, and the deposition time is 2-10 minutes. Prior to depositing the functional layer, a transition layer is deposited to reduce stress between the coating and the substrate and improve the coating's bonding strength. The functional layer primarily provides wear resistance and anti-adhesion properties. During subsequent deposition, the transition layer helps ensure good bonding between layers.

[0031] In some specific embodiments, when depositing the AlCrN transition layer, the nitrogen flow rate is 400 to 500 sccm; the substrate bias voltage gradually changes from -50 to -70 V to -30 to -45 V; and the deposition time is 2 to 10 min.

[0032] In some specific embodiments, when depositing the AlCrN functional layer, the nitrogen gas flow rate is 400 to 550 sccm; the substrate bias voltage is -30 to -50 V; and the deposition time is 10 to 20 min.

[0033] In some specific embodiments, when depositing the ZrAlCrN functional layer, the nitrogen flow rate is 400 to 550 sccm; the substrate bias voltage is -30 to -60 V; and the deposition time is 10 to 20 min.

[0034] In some specific embodiments, when depositing the ZrAlCrN transition layer, the nitrogen flow rate is 400 to 550 sccm, the substrate bias voltage is -30 to -60 V, and the deposition time is 5 to 10 minutes. Depositing the ZrAlCrN transition layer allows the high-aluminum ZrAlCrN layer to transition to a high-zirconium ZrAlCrN layer, reducing internal stress caused by the sudden change in composition.

[0035] In some specific embodiments, when depositing the ZrAlCrN functional layer, the nitrogen flow rate is 400 to 550 sccm; the substrate bias voltage is -30 to -60 V, and the deposition time is 10 to 20 min.

[0036] In some specific embodiments, when depositing the ZrCrCN transition layer, the nitrogen flow rate is 400-550 sccm; the acetylene flow rate is 5-10 sccm; the substrate bias voltage is -30--60 V, and the deposition time is 2-10 min.

[0037] In some specific embodiments, when depositing the CrCN layer, the nitrogen flow rate is 400-550 sccm; the acetylene flow rate is 20-100 sccm; the substrate bias voltage is -30--60 V, and the deposition time is 10-20 min.

[0038] By adjusting the appropriate target current, substrate bias, and gas flow rate, it is beneficial to control the hardness, wear resistance, and anti-adhesion properties of the composite coating.

[0039] In some embodiments, the step of etching the substrate is further included before the deposition; the etching is performed by low-pressure glow discharge.

[0040] The substrate of the present invention is etched using high-energy Ar ions using LGD (low-pressure glow discharge). Compared with conventional Ar ion etching, it is more efficient and has better etching effects, and does not require a high bias voltage. Compared with metal ion etching, LGD etching is easier to control the etching intensity, does not excessively damage the substrate, and does not leave a metal layer on the substrate.

[0041] In some specific embodiments, the etching comprises the following steps:

[0042] LGD etching is used. During the etching process, the Cr target and the LGD power supply connected to the Al target are turned on, the target current is set to 90-120A, the substrate bias is set to -300-500V, the argon flow rate is 200-400sccm, the heating temperature is 300-600℃, and the etching time is 10-30min.

[0043] Specifically, during the etching process, the Cr target shield is closed, and the electrons emitted from the arc discharge move toward the Al target. During the movement, they bombard the argon gas to obtain high-energy Ar ions, which etch the substrate under the action of negative bias voltage.

[0044] In some specific embodiments, the substrate is ultrasonically cleaned before etching.

[0045] The third aspect of the present invention provides a cutting tool, wherein the cutting tool comprises the composite coating according to the first aspect of the present invention; or, comprises the composite coating prepared by the preparation method according to the second aspect of the present invention.

[0046] Specifically, when the cutting tool contains the composite coating prepared by the preparation method described in the second aspect of the present invention, it means that the cutting tool is used as a substrate to deposit the composite coating.

[0047] A fourth aspect of the present invention provides an application of the tool described in the third aspect of the present invention in titanium alloy processing.

[0048] In some embodiments, the tool is used for cutting and milling titanium alloys.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) The present invention provides a composite coating that utilizes C and Zr element doping to form CrCN, ZrCrCN, and ZrAlCrN layers, which can serve as a friction-reducing layer, reduce the friction coefficient of the composite coating, improve the wear resistance of the composite coating, and enhance its ability to resist adhesive wear. Furthermore, the composite coating of the present invention includes an AlCrN layer and a CrN layer, which can serve as support for the friction-reducing layer, improve wear resistance and oxidation resistance, thereby improving the durability of the composite coating and thereby increasing the service life of the product protected by the composite coating.

[0051] (2) The present invention uses physical vapor deposition technology to prepare composite coatings, and further enhances the performance of the composite coatings by combining different modes and parameters. For example, by using a gradient mode to deposit the transition layer, including using a gradient target current, gradient substrate bias, or gradient gas flow, the coating structure transitions continuously, and the residual stress of the coating is low, thereby improving the bonding strength of the coating. At the same time, the combination of different parameters is conducive to further enhancing the wear resistance and adhesive wear resistance of the composite coating.

[0052] (3) The composite coating obtained by the present invention has the advantages of high hardness, high bonding strength, high wear resistance and high resistance to adhesive wear, and has good oxidation resistance. The layers of the composite coating or between the composite coating and the substrate have good bonding force, and are suitable for use as tool coatings. The prepared tools also have the characteristics of high wear resistance and resistance to adhesive wear. When cutting titanium alloys, it is not easy to cause chipping or adhesive wear, which helps to improve the tool life. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 The SEM image and the schematic diagram of the coating structure of the composite coating prepared in Example 2 of the present invention are shown; wherein, Figure 1 Figure (a) is a SEM image. Figure 1 Figure (b) is a schematic diagram of the coating structure.

[0054] Figure 2 The ball mark morphology and indentation morphology of the composite coating prepared in Example 2 of the present invention; wherein, Figure 2 Figure (a) shows the ball mark morphology. Figure 2 Figure (b) shows the indentation morphology.

[0055] Figure 3 The scratch morphology and bonding strength of the composite coatings prepared in Examples 1-2 and Comparative Example 1 are shown.

[0056] Figure 4The morphology of the tool surface after milling titanium alloy using the tool containing the composite coating obtained by the preparation methods of Examples 1-2 and Comparative Example 1. DETAILED DESCRIPTION

[0057] The present invention is further described in detail below using specific examples. Unless otherwise specified, the raw materials, reagents, and apparatus used in the examples and comparative examples are available from conventional commercial sources or by conventional methods. Unless otherwise specified, all experimental or testing methods are conventional in the art.

[0058] The following describes the details in conjunction with specific embodiments and comparative examples.

[0059] Example 1

[0060] A composite coating, the preparation method of which comprises the following steps:

[0061] S1. The carbide substrate was ground and polished, ultrasonically cleaned in anhydrous ethanol, dried, and loaded into the furnace chamber of the Platit 411plus equipment with a distance of 40 mm between the substrate and the target. The vacuum was then evacuated to a vacuum degree of 3×10 -3 Pa, heating the substrate to 450 ° C; argon gas was introduced into the furnace chamber to ensure a gas flow of 300 sccm; there were three columnar targets in the furnace, target 1 was Zr 99.9 , 2# target is Al 99.9 , 3# target is Cr 99.9 , target 2# is connected to an external LGD (low voltage glow discharge) anode power supply; target 3# and LGD power supply are turned on, target current is set to 140A and substrate bias is set to -50V during etching, target 3# shielding cover is closed, target 3# arc discharges, electrons escaping from the back of the target material move toward target 2#, bombarding the argon gas in the furnace to obtain high-energy Ar ions during the movement, and the Ar ions bombard the substrate under the action of negative bias, and the etching time is 12min;

[0062] S2. After etching, introduce argon and nitrogen, with a nitrogen flow rate of 350sccm and an argon flow rate of 30sccm, and open the Cr 99.9 The target current was gradually changed from 100A to 180A, the nitrogen flow rate was gradually changed from 300sccm to 450sccm, the substrate bias was gradually changed from -120V to -60V, and the CrN transition layer was deposited for 2min.

[0063] S3. Continue to introduce argon and nitrogen to maintain Cr 99.9 The target was powered on, the target current was kept constant at 160 A, the nitrogen flow rate was kept constant at 450 sccm, and the substrate bias was kept constant at -60 V. The CrN functional layer was deposited for 12 min.

[0064] S4. Open Cr99.9 Target and Al 99.9 Target, Cr 99.9 The target current gradually changes from 160A to 110A, Al 99.9 The target current was gradually changed from 110A to 180A, the nitrogen flow rate was 400sccm, and the substrate bias was gradually changed from -60V to -40V to deposit the AlCrN transition layer for 2min.

[0065] S5. Nitrogen is introduced at a flow rate of 450 sccm, Cr 99.9 Target and Al 99.9 The target continues to be energized, Cr 99.9 The target current was kept at 110A, Al 99.9 The target current was 180 A, the substrate bias was -40 V, and the multilayer coating was deposited in a multilayer mode. Ten nano-multilayer AlCrN functional layers were deposited, and the deposition time was 12 min.

[0066] S6. Open Cr 99.9 Target, Al 99.9 Target and Zr 99.9 Target, Cr 99.9 The target current is 110A, Al 99.9 The target current is 180A, Zr 99.9 The target current was 130 A, the substrate bias was -40 V, and the ZrAlCrN functional layer was deposited for 12 min.

[0067] S7. Maintain Cr 99.9 Target, Al 99.9 Target and Zr 99.9 Target electrification, Cr 99.9 The target current gradually changes from 110A to 90A, Al 99.9 The target current gradually changes from 180A to 120A, Zr 99.9 The target current was gradually changed from 130A to 160A, the substrate bias was set at -40V, and the ZrAlCrN transition layer was deposited for 2min.

[0068] S8. Keep Cr 99.9 Target, Al 99.9 Target and Zr 99.9 Target electrification, Cr 99.9 The target current is kept at 90A, Al 99.9 The target current is kept at 120A, Zr 99.9 The target current was maintained at 160 A, the substrate bias was at -40 V, and the ZrAlCrN functional layer was deposited for 12 min.

[0069] S9. Maintain vacuum at 2×10 -3Pa, nitrogen and acetylene are introduced, the maximum nitrogen flow rate is 450sccm, the acetylene flow rate is 5sccm, and Al is turned off. 99.9 Target, open Cr 99.9 Target and Zr 99.9 Target, Zr 99.9 The target current gradually changes from 160A to 130A, Cr 99.9 The target current was gradually changed from 90A to 160A, the substrate bias was at -40V, and the ZrCrCN transition layer was deposited for 5min.

[0070] S10. Turn off Zr 99.9 Target, open Cr 99.9 Target, maintain vacuum at 2×10 -3 Pa, nitrogen and acetylene are introduced, nitrogen flow rate is 400sccm, acetylene flow rate is 30sccm, Cr 99.9 The target current was maintained at 160 A, the substrate bias was at -40 V, and the CrCN layer was deposited for 12 min. After the deposition, a composite coating was obtained.

[0071] In this embodiment, the composite coating has a thickness of 3.6 μm, a dense coating structure without pores, good bonding between the coatings and between the coating and the substrate, and exhibits good resistance to adhesive wear during high-speed milling of TiAl6V4 titanium alloy.

[0072] Example 2

[0073] A composite coating, the SEM image of which is as follows Figure 1 As shown in Figure (a) (the scale bar is 5 μm), the coating structure is as follows Figure 1 As shown in Figure (b); the specific preparation method comprises the following steps:

[0074] S1. The cemented carbide substrate was ground and polished, ultrasonically cleaned in anhydrous ethanol, dried, and placed in the Platit411plus furnace chamber with a distance of 50 mm between the substrate and the target. The vacuum was then evacuated to a vacuum degree of 2.5 × 10 -3 Pa, heating the substrate to 400 ° C; argon gas was introduced into the furnace chamber to ensure a gas flow of 350 sccm; there were three columnar targets in the furnace, target 1 was Zr 99.9 , 2# target is Al 99.9 , 3# target is Cr 99.9 , target 2# is connected to an external LGD (low voltage glow discharge) anode power supply; target 3# and LGD power supply are turned on, target current is set to 120A and substrate bias is set to -400V during etching, shield cover of target 3# is closed, target 3# arc discharges, electrons escaping from the back of the target material move toward target 2#, bombarding the argon gas in the furnace to generate high-energy Ar ions during the movement, and Ar ions bombard the substrate under the action of negative bias, and the etching time is 15min;

[0075] S2. After etching, introduce argon and nitrogen, with a nitrogen flow rate of 300 sccm and an argon flow rate of 20 sccm; open Cr 99.9 The target current was gradually changed from 100A to 160A, the nitrogen flow rate was gradually changed from 300sccm to 450sccm, the substrate bias was gradually changed from -120V to -60V, and the CrN transition layer was deposited for 5min.

[0076] S3. Continue to introduce argon and nitrogen to maintain Cr 99.9 The target was powered on, the target current was kept constant at 160 A, the nitrogen flow rate was kept constant at 450 sccm, and the substrate bias was kept constant at -60 V. The CrN functional layer was deposited for 15 min.

[0077] S4. Open Cr 99.9 Target and Al 99.9 Target, Cr 99.9 The target current gradually changes from 160A to 110A, Al 99.9 The target current was gradually changed from 110A to 175A, the nitrogen flow rate was 450sccm, and the substrate bias was gradually changed from -60V to -40V to deposit the AlCrN transition layer (CrAlN transition layer) for 5min.

[0078] S5. Nitrogen gas was introduced at a flow rate of 450 sccm, Cr99.9 target and Al 99.9 The target continues to be energized, Cr 99.9 The target current was kept at 110A, Al 99.9 The target current was 175 A, the substrate bias was -40 V, and the multilayer coating was deposited in a multilayer mode. Ten nano-multilayer AlCrN functional layers were deposited for 10 min.

[0079] S6. Open Cr at the same time 99.9 Target, Al 99.9 Target and Zr 99.9 Target, Cr 99.9 The target current is 110A, Al 99.9 The target current is 175A, Zr 99.9 The target current was 130 A, the substrate bias was -40 V, and the ZrAlCrN functional layer was deposited for 15 min.

[0080] S7. Maintain Cr 99.9 Target, Al 99.9 Target and Zr 99.9 Target electrification, Cr 99.9 The target current gradually changes from 110A to 90A, Al 99.9 The target current gradually changes from 175A to 120A, Zr 99.9The target current was gradually changed from 130 A to 160 A, the substrate bias was set at -40 V, and the ZrAlCrN transition layer was deposited for 5 min.

[0081] S8. Keep Cr 99.9 Target, Al 99.9 Target and Zr 99.9 Target electrification, Cr 99.9 The target current is kept at 90A, Al 99.9 The target current is kept at 120A, Zr 99.9 The target current was maintained at 160 A, the substrate bias was at -40 V, and the ZrAlCrN functional layer was deposited for 12 min.

[0082] S9. Introduce nitrogen and acetylene, nitrogen flow rate 450sccm, acetylene flow rate 5sccm, close Al 99.9 Target, open Cr 99.9 Target and Zr 99.9 Target, Zr 99.9 The target current gradually changes from 160A to 130A, Cr 99.9 The target current was gradually changed from 90A to 160A, the substrate bias was at -40V, and the ZrCrCN transition layer was deposited for 5min.

[0083] S10. Turn off Zr 99.9 Target, open Cr 99.9 Target, nitrogen and acetylene, nitrogen flow rate 400sccm, acetylene flow rate 20sccm, Cr 99.9 The target current was maintained at 160 A, the substrate bias was at -40 V, and the CrCN layer was deposited for 15 min. After the deposition, a composite coating was obtained.

[0084] The composite coating of this embodiment has a thickness of 3.6 μm, a dense coating structure without pores, good bonding between the coatings and between the coating and the substrate, and poorer adhesive wear resistance than that of Example 1 during high-speed milling of TiAl6V4 titanium alloy.

[0085] Example 3

[0086] A method for preparing a composite coating is different from that of Example 2 in that: in step S10, the flow rate of acetylene is 110 sccm, and the rest is the same as that of Example 2.

[0087] In this embodiment, due to the change in the flow rate of acetylene, the wear resistance of the obtained composite coating is worse than that of Example 2, and the adhesive wear resistance is worse than that of Example 2 when high-speed milling TiAl6V4 titanium alloy.

[0088] Comparative Example 1

[0089] A composite coating, the preparation method of which comprises the following steps:

[0090] S1. The cemented carbide substrate was ground and polished, ultrasonically cleaned in anhydrous ethanol, dried, and placed in the Platit411plus furnace chamber with a distance of 50 mm between the substrate and the target. The vacuum was then evacuated to a vacuum degree of 2.5 × 10 -3 Pa, heating the substrate to 400 ° C; argon gas was introduced into the furnace chamber to ensure a gas flow of 350 sccm; there were three columnar targets in the furnace, target 1 was Zr 99.9 , 2# target is Al 99.9 , 3# target is Cr 99.9 , target 2# is connected to an external LGD (low voltage glow discharge) anode power supply; target 3# and LGD power supply are turned on, target current is set to 120A and substrate bias is set to -400V during etching, shield cover of target 3# is closed, target 3# arc discharges, electrons escaping from the back of the target material move toward target 2#, bombarding the argon gas in the furnace to generate high-energy Ar ions during the movement, and Ar ions bombard the substrate under the action of negative bias, and the etching time is 15min;

[0091] S2. Open Cr 99.9 Target and Al 99.9 Target, Cr 99.9 Target current 110A, Al 99.9 The AlCrN transition layer was deposited at a target current of 175 A, a nitrogen flow rate of 450 sccm, a substrate bias of -40 V, and a deposition time of 5 min.

[0092] S3. Maintain nitrogen gas flow rate at 450 sccm, Cr 99.9 Target and Al 99.9 The target continues to be energized, Cr 99.9 The target current was kept at 110A, Al 99.9 The target current was 175 A, the substrate bias was -40 V, and the multilayer coating was deposited in a multilayer mode. The nano-multilayer AlCrN functional layer was deposited for 10 min.

[0093] S4. Open Cr at the same time 99.9 Target, Al 99.9 Target and Zr 99.9 Target, Cr 99.9 The target current is 110A, Al 99.9 The target current is 175A, Zr 99.9 The target current was 130 A, the substrate bias was -40 V, and the ZrAlCrN functional layer was deposited for 15 min.

[0094] S5. Maintain Cr 99.9 Target, Al 99.9 Target and Zr 99.9Target electrification, Cr 99.9 The target current gradually changes from 110A to 90A, Al 99.9 The target current gradually changes from 175A to 120A, Zr 99.9 The target current was gradually changed from 130 A to 160 A, the substrate bias was set at -40 V, and the ZrAlCrN transition layer was deposited for 5 min.

[0095] S6. Maintain Cr 99.9 Target, Al 99.9 Target and Zr 99.9 Target electrification, Cr 99.9 The target current is kept at 90A, Al 99.9 The target current is kept at 120A, Zr 99.9 The target current was maintained at 160 A, the substrate bias was at -40 V, and the ZrAlCrN functional layer was deposited for 12 min.

[0096] S7. Introduce nitrogen and acetylene, nitrogen flow rate 450sccm, acetylene flow rate 5sccm, close Al 99.9 Target, open Cr 99.9 Target and Zr 99.9 Target, Zr 99.9 The target current gradually changes from 160A to 130A, Cr 99.9 The target current was gradually changed from 90A to 160A, the substrate bias was at -40V, and the ZrCrCN transition layer was deposited for 5min.

[0097] S8. Turn off Zr 99.9 Target, open Cr 99.9 Target, nitrogen and acetylene, nitrogen flow rate 400sccm, acetylene flow rate 20sccm, Cr 99.9 The target current was maintained at 160 A, the substrate bias was at -40 V, and the CrCN layer was deposited for 15 min. After the deposition, a composite coating was obtained.

[0098] The thickness of the composite coating in this comparative example is 3.6 μm, the coating structure is dense and free of pores, and the coatings are well bonded to each other and to each other. However, compared with Examples 1 and 2, due to the lack of a CrN transition layer and a CrN functional layer, the bonding force between the coating and the substrate is lower than that of Examples 1 and 2, and the resistance to adhesive wear is also poor.

[0099] Result detection

[0100] The composite coatings obtained in the above examples and comparative examples were tested for performance. Figures 2-4 The results are analyzed as follows:

[0101] 1. Ball mark test

[0102] The composite coating obtained in Example 2 was tested using a Supu BCT1000 ball pit tester. The results are as follows: Figure 2 As shown in Figure (a) in the figure, it can be seen that the total thickness of the composite coating obtained in Example 2 is 3.6 μm.

[0103] 2. Indentation test

[0104] The composite coating obtained in Example 2 was tested using Laizhou Huayin HR-150A Rockwell hardness tester. The results are as follows: Figure 2 As shown in Figure (b), the indentation bonding strength of the composite coating is HF1, and the bonding strength between the layers and between the coating and the substrate is high.

[0105] 3. Scratch test

[0106] The composite coatings of the embodiment and the comparative example were tested using Anton Paar RST3 scratch tester. The results are as follows: Figure 3 shown. Figure 3 The scratch morphology and bonding strength of the composite coatings prepared in Examples 1 and 2 and Comparative Example 1 are shown. It can be seen that the composite coating in Example 1 has the highest bonding strength with the substrate, while that in Example 2 is lower than that in Example 1, and the bonding strength in Comparative Example 1 is the worst.

[0107] 4. Milling TiAl6V4 titanium alloy test

[0108] Using the same preparation method as in the examples and comparative examples, the substrate was replaced with a tool used for milling titanium alloy, and a composite coating was deposited on the tool using the same parameters as in the examples and comparative examples; the tool was a cemented carbide tool with a diameter of 6 mm; the obtained tool was used to mill TiAl6V4 titanium alloy at a processing speed of 3200 rpm for 200 minutes, and its adhesive wear was observed.

[0109] The test results are as follows Figure 4 shown. Figure 4 The following figures show the morphology of the tool faces after milling titanium alloy using the composite coatings prepared using the methods of Examples 1-2 and Comparative Example 1. It can be seen that the tool in Comparative Example 1 exhibits the most severe wear, with slight edge chipping, while the tool in Example 1 exhibits the least wear, demonstrating excellent resistance to adhesive wear. Example 2 also exhibits less wear than Comparative Example 1, but exhibits more severe adhesive wear than Example 1, with noticeable white, reflective adhesive deposits on the cutting edge.

[0110] In summary, the present invention provides a composite coating that improves the wear resistance and oxidation resistance of the composite coating and enhances its ability to resist adhesive wear through the design of the coating composition and structure. The composite coating is prepared using physical vapor deposition technology, and further improved through the combination of different modes and different parameters to improve the wear resistance and adhesive wear resistance of the composite coating. The resulting composite coating has the advantages of high hardness, high bonding strength, high wear resistance and high adhesive wear resistance, and has good oxidation resistance. It is suitable for use as a tool coating. The resulting tool is not prone to chipping or adhesive wear when performing titanium alloy cutting, which significantly improves the tool life.

[0111] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A composite coating, characterized in that: The composite coating comprises a CrN layer, an AlCrN layer, a ZrAlCrN layer, a ZrCrCN layer and a CrCN layer which are stacked in sequence; the CrCN layer is a surface layer.

2. The composite coating according to claim 1, characterized in that The thickness of the composite coating is 2 to 4 μm.

3. The composite coating according to claim 1 or 2, characterized in that: The CrN layer, the AlCrN layer and the ZrAlCrN layer each independently include at least two coating layers.

4. A method for preparing a composite coating according to any one of claims 1 to 3, characterized in that: The following steps are involved: A CrN layer, an AlCrN layer, a ZrAlCrN layer, a ZrCrCN layer and a CrCN layer are sequentially deposited on the substrate to obtain the composite coating.

5. The preparation method according to claim 4, characterized in that The preparation method comprises the following steps: A CrN transition layer, a CrN functional layer, an AlCrN transition layer, an AlCrN functional layer, a ZrAlCrN functional layer, a ZrAlCrN transition layer, a ZrAlCrN functional layer, a ZrCrCN transition layer and a CrCN layer are sequentially deposited on the substrate to obtain the composite coating.

6. The preparation method according to claim 5, characterized in that The deposition process comprises the following steps: The Cr target current was set to gradually change from 90 to 110 A to 150 to 180 A to deposit the CrN transition layer; the Cr target current was set to 150 to 180 A to deposit the CrN functional layer; The Cr target current was set to gradually change from 150-180A to 90-130A, and the Al target current was set to gradually change from 90-110A to 150-180A to deposit the AlCrN transition layer; the Cr target current was set to 90-130A, and the Al target current was set to 150-180A to deposit the AlCrN functional layer; The Cr target current is set to 90-130A, the Al target current is 150-180A, and the Zr target current is 110-150A to deposit the ZrAlCrN functional layer; the Cr target current is set to 90-130A, the Al target current is gradually changed from 150-180A to 110-140A, and the Zr target current is gradually changed from 110-150A to 150-180A to deposit the ZrAlCrN transition layer; the Cr target current is set to 90-130A, the Al target current is 110-140A, and the Zr target current is 150-180A to deposit the ZrAlCrN functional layer; The Cr target current was set to gradually change from 90-130A to 150-180A, and the Zr target current was set to gradually change from 150-180A to 110-150A to deposit the ZrCrCN transition layer; The Cr target current was set to 150-180 A to deposit the CrCN layer.

7. The preparation method according to claim 6, characterized in that The deposition time is 5 to 20 minutes; And / or, during the deposition process, the substrate bias voltage is set to -30 to -120 V; the substrate bias voltage is gradual or constant.

8. The preparation method according to any one of claims 4 to 7, characterized in that The method also includes a substrate etching step before the deposition; the etching is performed by low-pressure glow discharge.

9. A cutting tool, characterized in that: The cutting tool comprises the composite coating according to any one of claims 1 to 3; or, comprises the composite coating prepared by the preparation method according to any one of claims 4 to 7.

10. Use of the cutting tool according to claim 9 in titanium alloy processing.

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