A method for preparing and application of an oxidation-resistant high-entropy nitride coating

Abstract

An antioxidant high-entropy nitride coating, relating to the field of coating technology, comprises: an AlCr transition layer and a (TiZrAlCrSi)N high-entropy nitride working layer sequentially disposed on the surface of a cemented carbide; wherein the atomic percentage of each element in the (TiZrAlCrSi)N high-entropy nitride working layer is Al 10-13 at.%, Cr 12-16 at.%, Ti 7-12 at.%, Zr 9-14 at.%, Si 5-7% at.%, and N 39-60 at.%; the present invention also provides a method for preparing the antioxidant high-entropy nitride coating and its application in the surface protection of cemented carbide.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and specifically to a method for preparing and applying an antioxidant high-entropy nitride coating. Background Technology

[0002] High-speed machining, as an advanced manufacturing technology, has made a significant contribution to high-precision manufacturing. Compared to conventional machining techniques, it combines high efficiency, high quality, and low consumption. During the cutting process, high-speed machining inevitably generates a large amount of heat. To ensure the normal use of cutting tools, most machining processes use cutting fluid to reduce the temperature. To promote the green transformation of high-speed machining, dry cutting technology has been proposed. However, dry cutting technology is a grinding process performed without cooling, lacking the cooling, lubrication, and chip removal functions of cutting fluid. This increases the friction area between the tool and the workpiece in the grinding zone, leading to increased cutting resistance, increased grinding vibration, and poor chip removal, significantly reducing workpiece surface quality and tool life. Typically, to overcome these problems, a high-temperature, high-hardness protective coating needs to be applied to the tool surface.

[0003] Most cutting tools are made of cemented carbide, which is much harder than high-speed steel and has advantages such as good chemical stability and heat resistance. It is widely used in cutting tools, nuclear power plants, aerospace, and automotive manufacturing. However, with the development of high-speed dry cutting technology, cemented carbide often encounters problems such as high-temperature oxidation, wear, and corrosion during use. When the operating temperature exceeds 600℃, the growth rate of the WO3 oxide layer on the cemented carbide surface increases rapidly with rising temperature, causing a sharp decline in the performance of the cemented carbide and significantly shortening the service life of cemented carbide cutting tools.

[0004] Therefore, coating the surface of cemented carbide with a protective coating is of significant practical importance. In Chinese invention patent CN116005109A, a high-entropy nitride anti-erosion coating and its preparation method and device are disclosed. The working layer of this coating is AlTiCrZrNbN high-entropy nitride, which has good hardness and H / E value, resulting in good mechanical properties, hardness, wear resistance and surface quality. However, the production cost of this working layer is high, and the film / substrate bonding force between the coating and the substrate is not high. Furthermore, its ability to hinder the diffusion of oxygen into the interior of cemented carbide during oxidation is not very good. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing and applying an antioxidant high-entropy nitride coating, which solves the problems of high cost, poor film / substrate adhesion to cemented carbide, and insufficient ability to hinder oxygen diffusion in existing coatings.

[0006] An antioxidant high-entropy nitride coating, comprising:

[0007] An AlCr transition layer and a (TiZrAlCrSi)N high-entropy nitride working layer are sequentially disposed on the surface of the cemented carbide.

[0008] The atomic percentage of each element in the (TiZrAlCrSi)N high-entropy nitride working layer is as follows: Al 10~13 at.%, Cr 12~16 at.%, Ti 7~12 at.%, Zr 9~14 at.%, Si 5~7% at.%, N 39~60 at.%.

[0009] Preferably, the AlCr transition layer has a thickness of 0.09~0.1μm, and the (TiZrAlCrSi)N high-entropy nitride working layer has a thickness of 1~1.1μm.

[0010] This invention also provides a method for preparing an antioxidant high-entropy nitride coating, comprising the following steps:

[0011] (1) Polish and ultrasonically clean the cemented carbide to remove rust and oil stains;

[0012] (2) Place the pretreated hard alloy into the vacuum chamber of the magnetron sputtering coating equipment, control the internal vacuum level, and introduce argon into the vacuum chamber. Then turn on the radio frequency power supply to perform glow discharge cleaning on the hard alloy for 10-15 minutes to remove the surface oxide layer.

[0013] (3) The hard alloy after glow discharge cleaning is subjected to magnetron sputtering to form an AlCr transition layer;

[0014] (4) Nitrogen gas is introduced into the vacuum chamber and the sample sputtered by magnetron sputtering is further magnetron sputtered to form a (TiZrAlCrSi)N high-entropy nitride working layer.

[0015] Preferably, in step (1), polishing is performed by sequentially grinding the surface of the cemented carbide with 400#, 600#, 800# and 1000# sandpaper.

[0016] Preferably, the ultrasonic cleaning in step (1) uses ethanol and acetone cleaning solution.

[0017] Preferably, in step (2), when the vacuum level of the vacuum chamber is lower than 5 × 10⁻⁶, -5 After Torr, continue evacuating to 5×10 -6 Torr, and set the RF power supply to 150W.

[0018] Preferably, in step (3), during the deposition of the AlCr transition layer, the power of the radio frequency power supply is set to 50W and the sputtering power of the AlCr metal target is set to 250W.

[0019] Preferably, in step (4), the nitrogen flux is 5~20 sccm, and the sputtering power of the AlCr metal target is set to 250W, the sputtering power of the TiZr metal target is 300W, and the sputtering power of the Si target is 100W.

[0020] Preferably, the AlCr metal target, TiZr metal target, and Si target are all powered by DC power.

[0021] The present invention also provides an application of an antioxidant high-entropy nitride coating in the surface protection of cemented carbide.

[0022] Compared with existing technologies, the present invention has the following advantages: Because the coating provided by the present invention has fine, uniform, and dense grains and is inexpensive, it exhibits excellent oxidation resistance under high-temperature operating conditions. Furthermore, since cemented carbide is primarily a W and Co alloy, directly applying magnetron sputtering coating to the cemented carbide would result in poor film adhesion. Therefore, when modifying the surface of the cemented carbide, the present invention first performs polishing, ultrasonic cleaning, and glow discharge cleaning to remove impurities and oxide layers from the surface. Subsequently, a physical vapor deposition of an AlCr transition layer is performed on the surface of the cemented carbide. To achieve high film / substrate adhesion, making the coating less prone to peeling, a (TiZrAlCrSi)N high-entropy nitride working layer is then deposited on the AlCr transition layer. During the deposition process, nitrogen atoms form nitrides with Al, Ti, Zr, Si, and Cr in the coating, which can further improve hardness. At the same time, Al, Cr, and Si will generate Al2O3, Cr2O3, and SiO2 protective oxide layers during oxidation, which can effectively prevent further diffusion of oxygen into the cemented carbide, improve the material's oxidation resistance, and solve the problem of insufficient adhesion between the coating and the cemented carbide.

[0023] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0024] Figure 1 The figures show the loading and unloading curves of the coating nanoindentation test in various embodiments of the present invention.

[0025] Figure 2 These are test diagrams showing the coating film / substrate adhesion performance of various embodiments of the present invention.

[0026] Figure 3 The images show cross-sectional views of coating wear scratches in various embodiments of the present invention. Detailed Implementation

[0027] To make the technical means, creative features, objectives, and effects of this invention clearer and easier to understand, the invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

[0028] Example 1

[0029] After polishing the cemented carbide with 400#, 600#, 800# and 1000# sandpaper in sequence, the polished cemented carbide was then ultrasonically cleaned with ethanol and acetone in sequence to make its surface clean.

[0030] A dry, clean hard alloy is placed into the vacuum chamber of a magnetron sputtering coating apparatus, which is then evacuated and heated simultaneously. When the vacuum level in the vacuum chamber is below 5 × 10⁻⁶... -5 After Torr, continue evacuating to 5×10 -6 After the torsion process, argon gas was introduced, and at the same time, the RF power supply was turned on and the power was set to 150W. The sample to be plated was then subjected to plasma glow cleaning for 13 minutes.

[0031] Then, the power of the RF power supply was controlled to be 50W and the power of the AlCr metal target was 250W to deposit an AlCr transition layer with a thickness of 0.098μm.

[0032] Keeping the RF power supply constant, nitrogen gas with a flow rate of 5 sccm was introduced. The power of the AlCr metal target was adjusted to 250W, the power of the TiZr metal target to 300W, and the sputtering power of the Si target to 100W. A (TiZrAlCrSi)N high-entropy nitride working layer was deposited to obtain a (TiZrAlCrSi)N high-entropy nitride working layer with a thickness of 1.03 μm.

[0033] The above coating was named N5. The prepared cemented carbide with the coating was placed in a high-temperature muffle furnace for high-temperature oxidation treatment at 800°C for 1 hour.

[0034] Example 2

[0035] After polishing the cemented carbide with 400#, 600#, 800# and 1000# sandpaper in sequence, the polished cemented carbide was then ultrasonically cleaned with ethanol and acetone in sequence to make its surface clean.

[0036] A dry, clean hard alloy is placed into the vacuum chamber of a magnetron sputtering coating apparatus, which is then evacuated and heated simultaneously. When the vacuum level in the vacuum chamber is below 5 × 10⁻⁶... -5 After Torr, continue evacuating to 5×10 -6After the torsion process, argon gas is introduced, and at the same time, the RF power supply is turned on and the power is set to 150W. The sample to be plated is then subjected to plasma glow cleaning for 15 minutes.

[0037] Then, the power of the RF power supply was controlled to be 50W and the power of the AlCr metal target was 250W to deposit an AlCr transition layer with a thickness of 0.09μm.

[0038] Keeping the RF power supply constant, nitrogen gas with a flow rate of 10 sccm was introduced. The power of the AlCr metal target was adjusted to 250W, the power of the TiZr metal target to 300W, and the sputtering power of the Si target to 100W. A (TiZrAlCrSi)N high-entropy nitride working layer was deposited to obtain a (TiZrAlCrSi)N high-entropy nitride working layer with a thickness of 1.1 μm.

[0039] The above coating was named N10. The prepared cemented carbide with the coating was placed in a high-temperature muffle furnace for high-temperature oxidation treatment at 800°C for 1 hour.

[0040] Example 3

[0041] After polishing the cemented carbide with 400#, 600#, 800# and 1000# sandpaper in sequence, the polished cemented carbide is then ultrasonically cleaned with ethanol and acetone in sequence to make its surface clean.

[0042] A dry, clean hard alloy is placed into the vacuum chamber of a magnetron sputtering coating apparatus, which is then evacuated and heated simultaneously. When the vacuum level in the vacuum chamber is below 5 × 10⁻⁶... -5 After Torr, continue evacuating to 5×10 -6 After the torsion process, argon gas is introduced, and at the same time, the RF power supply is turned on and the power is set to 150W. The sample to be plated is then subjected to plasma glow cleaning for 15 minutes.

[0043] Then, the power of the RF power supply was controlled to be 50W and the power of the AlCr metal target was 250W to deposit an AlCr transition layer with a thickness of 0.09μm.

[0044] Keeping the RF power supply constant, nitrogen gas with a flow rate of 15 sccm was introduced. The power of the AlCr metal target was adjusted to 250W, the power of the TiZr metal target to 300W, and the sputtering power of the Si target to 100W. A (TiZrAlCrSi)N high-entropy nitride working layer was deposited to obtain a (TiZrAlCrSi)N high-entropy nitride working layer with a thickness of 1.1 μm.

[0045] The above coating was named N15. The prepared cemented carbide with the coating was placed in a high-temperature muffle furnace for high-temperature oxidation treatment at 800°C for 1 hour.

[0046] Example 4

[0047] After polishing the cemented carbide with 400#, 600#, 800# and 1000# sandpaper in sequence, the polished cemented carbide was then ultrasonically cleaned with ethanol and acetone in sequence to make its surface clean.

[0048] A dry, clean hard alloy is placed into the vacuum chamber of a magnetron sputtering coating apparatus, which is then evacuated and heated simultaneously. When the vacuum level in the vacuum chamber is below 5 × 10⁻⁶... -5 After Torr, continue evacuating to 5×10 -6 After the torsion process, argon gas is introduced, and at the same time, the RF power supply is turned on and the power is set to 150W. The sample to be plated is then subjected to plasma glow cleaning for 10 minutes.

[0049] Then, the power of the RF power supply was controlled to be 50W and the power of the AlCr metal target was 250W to deposit an AlCr transition layer with a thickness of 0.1μm.

[0050] Keeping the power of the RF power supply constant, nitrogen gas with a flow rate of 20 sccm was introduced, and the power of the AlCr metal target was adjusted to 250W, the power of the TiZr metal target to 300W, and the sputtering power of the Si target to 100W. A (TiZrAlCrSi)N high-entropy nitride working layer was deposited to obtain a (TiZrAlCrSi)N high-entropy nitride working layer with a thickness of 1 μm.

[0051] The above coating was named N20. The prepared cemented carbide with the coating was placed in a high-temperature muffle furnace for high-temperature oxidation treatment at 800°C for 1 hour.

[0052] The performance of the four embodiments prepared according to the present invention was tested as follows:

[0053] (1) Coating hardness test

[0054] For each embodiment, six test points were selected, and the test method is as follows:

[0055]

[0056] Test results are as follows Figure 1 As shown, according to Figure 1 It can be calculated that the hardness of N20 is the highest at 28.8 GPa. Moreover, the comparison between Example 2 and Example 3 shows that increasing the flow rate of nitrogen can effectively improve the hardness of the coating.

[0057] (2) Membrane / substrate bonding performance test

[0058] The test conditions are as follows:

[0059]

[0060] Test results are as follows Figure 2 As shown, combining light microscopy images and acoustic signals, the film / substrate adhesion of N2O before oxidation treatment reached 160 N; and from... Figure 2 The comparison between the oxidation treatment before and after the various embodiments shows that the film / substrate bonding force is slightly reduced due to the formation of an oxide film on the surface of the cemented carbide.

[0061] (3) Wear test before and after oxidation

[0062] Each sample group was tested in triplicate, under the following conditions:

[0063]

[0064] Test results are as follows Figure 3 As shown, the four embodiments obtained wear scratch cross-sectional diagrams before and after oxidation through the same wear test. It can be seen that the cross-sectional area of ​​each scratch is similar before and after oxidation, and N20 has the smallest wear scratch cross-sectional area and the lowest wear rate. This indicates that the wear resistance properties of the coating are similar before and after oxidation, and the oxidation treatment does not reduce the wear resistance of the coating.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing an antioxidant high-entropy nitride coating, characterized in that, Includes the following steps: (1) Polish and ultrasonically clean the cemented carbide to remove rust and oil stains; (2) Place the pretreated hard alloy into the vacuum chamber of the magnetron sputtering coating equipment, control the internal vacuum level, and introduce argon into the vacuum chamber. Then turn on the radio frequency power supply to perform glow discharge cleaning on the hard alloy for 10-15 minutes to remove the surface oxide layer. (3) The hard alloy after glow discharge cleaning is subjected to magnetron sputtering to form an AlCr transition layer; (4) Nitrogen gas is introduced into the vacuum chamber and the sample sputtered by magnetron sputtering is further magnetron sputtered to form a (TiZrAlCrSi)N high-entropy nitride working layer. The nitrogen gas flux is 5~20 sccm, and the sputtering power of AlCr metal target is set to 250W, the sputtering power of TiZr metal target is 300W, and the sputtering power of Si target is 100W.

2. The method for preparing an antioxidant high-entropy nitride coating according to claim 1, characterized in that, The thickness of the AlCr transition layer is 0.09~0.1μm, and the thickness of the (TiZrAlCrSi)N high-entropy nitride working layer is 1~1.1μm.

3. The method for preparing an antioxidant high-entropy nitride coating according to claim 1, characterized in that, In step (1), polishing is done by using 400#, 600#, 800# and 1000# sandpaper to grind the surface of the cemented carbide in sequence.

4. The method for preparing an antioxidant high-entropy nitride coating according to claim 1, characterized in that, In step (1), ultrasonic cleaning uses ethanol and acetone cleaning solutions.

5. The method for preparing an antioxidant high-entropy nitride coating according to claim 1, characterized in that, In step (2), when the vacuum level of the vacuum chamber is lower than 5×10 -5 After Torr, continue evacuating to 5×10 -6 Torr, and set the RF power supply to 150W.

6. The method for preparing an antioxidant high-entropy nitride coating according to claim 1, characterized in that, In step (3), during the deposition of the AlCr transition layer, the power of the RF power supply is set to 50W and the sputtering power of the AlCr metal target is set to 250W.

7. The method for preparing an antioxidant high-entropy nitride coating according to claim 1, characterized in that, The AlCr, TiZr, and Si targets all use DC power supplies.

8. The application of the antioxidant high-entropy nitride coating prepared by the method for preparing the antioxidant high-entropy nitride coating according to claim 1 in the surface protection of cemented carbide.

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