A method for preparing a corrosion-resistant CoCrNiTiN medium-entropy alloy nitride film

Abstract

The application relates to a preparation method of a corrosion-resistant CoCrNiTiN medium-entropy alloy nitride film, and relates to a film material preparation method. The application aims to solve the problem that existing cutters and engineering equipment will face corrosion failure risks when serving in a saline-alkali environment. The method comprises the following steps: one, pretreatment; two, pre-sputtering a titanium target; three, magnetron sputtering of a cobalt-chromium-nickel alloy target and a titanium single-element target, so that a N-enhanced CoCrNiTiN medium-entropy nitride film is obtained on the surface of a workpiece. The application realizes the improvement of the corrosion resistance of the nitride film under the premise of keeping the medium-entropy structure through the synergistic effect of the nitrogen-promoted structural crystallization in the film and the multi-component solid solution in the medium-entropy structure. The application has a simple process and avoids complicated steps in the preparation process. The application can obtain a corrosion-resistant CoCrNiTiN medium-entropy alloy nitride film.

Description

Technical Field

[0001] The present invention relates to a method for preparing a thin film material, and in particular to a method for preparing a corrosion-resistant medium-entropy alloy nitride thin film. Background Art

[0002] Medium-entropy alloy nitride (MEAN) thin films, originating from bulk medium-entropy alloys, have garnered significant research interest over the past decade. From a thermodynamic perspective, MEAN films favor the formation of multicomponent solid solution phases rather than complex intermetallic compounds due to the high mixing entropy effect resulting from the increased number of principal elements. Kinetically, the significant lattice distortion caused by the large difference in atomic size reduces the cooperative diffusion between different elements, thereby promoting the formation of nanocrystalline or even amorphous structures. The prepared MEAN films exhibit numerous exceptional properties unmatched by conventional nitride films, such as high hardness, excellent wear and corrosion resistance, and strong diffusion barrier capability. Therefore, MEAN films hold great potential for applications such as tool and engineering equipment protection.

[0003] Traditional alloy materials have limited performance and may face severe corrosion failure risks when operating in extreme environments. For example, in marine environments, complex natural environments such as salt, alkali, and seawater impact can cause severe corrosion damage to engineering equipment. There is an urgent need for a novel and effective solution that can meet the needs of equipment in various environments and extend the service life of workpieces and equipment. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem that existing cutting tools and engineering equipment face the risk of corrosion failure when serving in saline-alkali environments, and to provide a method for preparing a corrosion-resistant CoCrNiTiN medium-entropy alloy nitride film.

[0005] A method for preparing a corrosion-resistant CoCrNiTiN medium-entropy alloy nitride film is specifically completed by the following steps:

[0006] 1. Preprocessing:

[0007] The surface of the pre-coated workpiece is ground with sandpaper, and then the workpiece is polished, and then the workpiece is ultrasonically cleaned and dried to obtain a pre-treated workpiece;

[0008] 2. Install the cobalt-chromium-nickel alloy target and the titanium target with equal atomic ratio on the target position of the DC power supply in sequence, load the pre-treated workpiece into the workpiece tray, close the vacuum chamber, and evacuate to 5×10 -3 Pa below; introduce argon gas into the vacuum chamber to maintain the pressure in the vacuum chamber at 0.5Pa~0.6Pa, turn on the negative bias power supply, adjust the negative bias voltage to -50V, then turn on the power supply of the titanium target and pre-sputter for a period of time;

[0009] 3. After the pre-sputtering is completed, turn off the power supply of the titanium target and introduce a mixture of nitrogen and argon to maintain the pressure in the vacuum chamber at 0.5Pa~0.6Pa. At the same time, turn on the power supply of the cobalt-chromium-nickel alloy target and the power supply of the titanium target, maintain a negative bias of -50V, and perform magnetron sputtering for a period of time to obtain an N-enhanced CoCrNiTiN medium-entropy nitride film on the surface of the workpiece.

[0010] Principle of the present invention:

[0011] The present invention achieves the improvement of corrosion resistance of the nitride film while maintaining the mesoentropy structure through the synergistic effect of nitrogen promoting structural crystallization in the film and multi-component solid solution in the mesoentropy structure.

[0012] The beneficial effects of the present invention are:

[0013] 1. The present invention provides a method for preparing a highly corrosion-resistant CoCrNiTiN medium-entropy alloy nitride film;

[0014] Second, the magnetron sputtering process is simple, avoiding the tedious steps in the preparation process;

[0015] 3. The film reacts during magnetron sputtering to form a nitride-enhanced medium-entropy alloy. Nitride is inert to ordinary metal materials, so it can reduce tool sticking when cutting ordinary metals and increase tool life. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is the XRD pattern of Comparative Example and Example 1;

[0017] Figure 2 This is a cross-sectional SEM morphology image of the corrosion-resistant CoCrNiTiN medium-entropy alloy nitride film prepared in Example 1;

[0018] Figure 3 This is a cross-sectional SEM morphology image of the corrosion-resistant CoCrNiTiN medium-entropy alloy nitride film prepared in Example 2;

[0019] Figure 4 Surface SEM morphology images of the comparative example, embodiment 1 and embodiment 2, the left image is the comparative example, the middle image is embodiment 1, and the right image is embodiment 2;

[0020] Figure 5 Impedance curves of Comparative Example and Example 1, Example 2, and Example 3 in 3.5 wt.% NaCl solution;

[0021] Figure 6 These are the moving point polarization curves of the comparative example and examples 1, 2, and 3 in 3.5 wt.% NaCl solution. DETAILED DESCRIPTION

[0022] Specific embodiment 1: This embodiment is a method for preparing a corrosion-resistant CoCrNiTiN medium-entropy alloy nitride film, which is specifically completed by the following steps:

[0023] 1. Preprocessing:

[0024] The surface of the pre-coated workpiece is ground with sandpaper, and then the workpiece is polished, and then the workpiece is ultrasonically cleaned and dried to obtain a pre-treated workpiece;

[0025] 2. Install the cobalt-chromium-nickel alloy target and the titanium target with equal atomic ratio on the target position of the DC power supply in sequence, load the pre-treated workpiece into the workpiece tray, close the vacuum chamber, and evacuate to 5×10 -3 Pa below; introduce argon gas into the vacuum chamber to maintain the pressure in the vacuum chamber at 0.5Pa~0.6Pa, turn on the negative bias power supply, adjust the negative bias voltage to -50V, then turn on the power supply of the titanium target and pre-sputter for a period of time;

[0026] 3. After the pre-sputtering is completed, turn off the power supply of the titanium target and introduce a mixture of nitrogen and argon to maintain the pressure in the vacuum chamber at 0.5Pa~0.6Pa. At the same time, turn on the power supply of the cobalt-chromium-nickel alloy target and the power supply of the titanium target, maintain a negative bias of -50V, and perform magnetron sputtering for a period of time to obtain an N-enhanced CoCrNiTiN medium-entropy nitride film on the surface of the workpiece.

[0027] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the material of the workpiece in step 1 is 42CrMo. The other steps are the same as those in specific embodiment 1.

[0028] Specific embodiment 3: This embodiment differs from specific embodiments 1 or 2 in that, in step 1, the surface of the pre-coated workpiece is polished using 240#, 600#, and 800# water-sandpaper, and 400#, 600#, and 800# metallographic sandpaper, respectively. The other steps are the same as those of specific embodiments 1 or 2.

[0029] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the polishing process described in step 1 is to polish the workpiece for 1 to 2 minutes using a polishing agent with a particle size of 2.5 μm. The other steps are the same as specific embodiments 1 to 3.

[0030] Specific embodiment 5: This embodiment differs from specific embodiments 1 to 4 in that the ultrasonic cleaning described in step 1 is: first, the workpiece is ultrasonically cleaned using petroleum ether for 10 to 15 minutes to remove oil stains on the workpiece surface, and then the workpiece is ultrasonically cleaned using anhydrous ethanol for 10 to 15 minutes to remove petroleum ether and other impurities on the workpiece surface. The other steps are the same as specific embodiments 1 to 4.

[0031] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that the flow rate of argon gas introduced into the vacuum chamber in step 2 is 10 sccm to 100 sccm. The other steps are the same as those of specific embodiments 1 to 5.

[0032] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that the pre-sputtering time in step 2 is 10 to 30 minutes and the power of the titanium target in step 2 is set to 30 W to 90 W. The other steps are the same as specific embodiments 1 to 6.

[0033] Specific embodiment 8: This embodiment differs from specific embodiments 1 to 7 in that the flow rate of nitrogen in the nitrogen and argon mixture in step 3 is 3 sccm to 20 sccm, and the flow rate of argon is 10 sccm to 100 sccm. The other steps are the same as specific embodiments 1 to 7.

[0034] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that the magnetron sputtering time in step 3 is 60 minutes to 120 minutes. The other steps are the same as those in specific embodiments 1 to 8.

[0035] Specific embodiment 10: This embodiment differs from specific embodiments 1 to 9 in that the power of the cobalt-chromium-nickel alloy target in step 3 is 100 W to 200 W, and the power of the titanium target is set to 30 W to 90 W. The other steps are the same as specific embodiments 1 to 9.

[0036] The following examples are used to verify the beneficial effects of the present invention:

[0037] Example 1: A method for preparing a corrosion-resistant CoCrNiTiN medium-entropy alloy nitride film is specifically completed by the following steps:

[0038] 1. Preprocessing:

[0039] The surface of the pre-coated workpiece is ground with sandpaper, and then the workpiece is polished, and then the workpiece is ultrasonically cleaned and dried to obtain a pre-treated workpiece;

[0040] The material of the workpiece described in step 1 is 42CrMo;

[0041] In step 1, the surface of the pre-coated workpiece is polished using water sandpaper 240#, 600#, 800#, and metallographic sandpaper 400#, 600#, and 800# in sequence;

[0042] The polishing process described in step 1 is as follows: polishing the workpiece for 1 minute using a polishing agent with a particle size of 2.5 μm;

[0043] The ultrasonic cleaning described in step 1 is as follows: first, the workpiece is ultrasonically cleaned with petroleum ether for 10 minutes to remove oil stains on the surface of the workpiece, and then the workpiece is ultrasonically cleaned with anhydrous ethanol for 10 minutes to remove petroleum ether and other impurities on the surface of the workpiece;

[0044] 2. Install the cobalt-chromium-nickel alloy target and the titanium target with equal atomic ratio on the target position of the DC power supply in sequence, load the pre-treated workpiece into the workpiece tray, close the vacuum chamber, and evacuate to 5×10 -3 Pa below; introduce argon gas into the vacuum chamber with a flow rate of 45sccm to maintain the pressure in the vacuum chamber at 0.5Pa, turn on the negative bias power supply, adjust the negative bias voltage to -50V, then turn on the power supply of the titanium target, pre-sputter for 10min,

[0045] The power of the titanium target in step 2 was set to 60W;

[0046] 3. After the pre-sputtering is completed, the power supply of the titanium target is turned off, and a mixture of nitrogen and argon is introduced to maintain the pressure in the vacuum chamber at 0.5 Pa. At the same time, the power supply of the cobalt-chromium-nickel alloy target and the power supply of the titanium target are turned on, and a negative bias voltage of -50 V is maintained. Magnetron sputtering is performed for 90 minutes, and an N-enhanced CoCrNiTiN medium-entropy nitride film is obtained on the surface of the workpiece, which is a corrosion-resistant CoCrNiTiN medium-entropy alloy nitride film.

[0047] In step 3, the flow rate of nitrogen in the mixture of nitrogen and argon is 5 sccm, and the flow rate of argon is 45 sccm;

[0048] In step 3, the power of the cobalt-chromium-nickel alloy target is 150W, and the power of the titanium target is set to 60W.

[0049] Example 2: This example differs from Example 1 in that the flow rate of nitrogen in the nitrogen and argon mixture in step 3 is 10 sccm, and the flow rate of argon is 45 sccm. The other steps and parameters are the same as those in Example 1.

[0050] Example 3: This example differs from Example 1 in that the flow rate of nitrogen in the nitrogen and argon mixture in step 3 is 20 sccm, and the flow rate of argon is 45 sccm. The other steps and parameters are the same as those in Example 1.

[0051] Comparative Example: This embodiment differs from Embodiment 1 in that the flow rate of nitrogen in the nitrogen and argon mixture in step 3 is 0 sccm, and the flow rate of argon is 45 sccm. The other steps and parameters are the same as those in Embodiment 1.

[0052] The comparative example is a pure CoCrNiTi alloy film without N element, and each embodiment is a medium entropy alloy nitride film with different N element contents. Different N element contents lead to different compositions and structures of the films, see Figure 1 As shown;

[0053] Figure 1 are the X-ray diffraction patterns of Comparative Example and Example 1;

[0054] from Figure 1 The XRD pattern shows that the diffraction peaks of the comparative example film are primarily composed of several strong matrix peaks and a broadened bun peak. Due to the thin film, strong diffraction peaks from the substrate silicon wafer are detected among the diffraction peaks. Compared with the comparative example, the XRD pattern of Example 1 clearly shows a sharp diffraction peak at approximately 45°. Further analysis reveals that this peak is CrN, confirming that the addition of nitrogen promotes the transformation of the film's crystal structure from amorphous to crystalline.

[0055] Figure 2 This is a SEM morphology image of the corrosion-resistant CoCrNiTiN medium-entropy alloy nitride film prepared in Example 1;

[0056] Figure 3 This is a SEM morphology image of the corrosion-resistant CoCrNiTiN medium-entropy alloy nitride film prepared in Example 2;

[0057] from Figure 2 and Figure 3 The cross-sectional SEM images also show that Example 1 and Example 2 have obvious columnar crystal features.

[0058] Figure 4 Surface SEM morphology images of the comparative example, embodiment 1 and embodiment 2, the left image is the comparative example, the middle image is embodiment 1, and the right image is embodiment 2;

[0059] From the surface SEM Figure 4 It can also be seen that compared with the smooth surface of the comparative example, the surfaces of Examples 1 and 2 have undulations of columnar crystals.

[0060] Using an electrochemical workstation equipped with a standard three-electrode system, the dynamic polarization curves and impedance curves of Example 1, Example 2, Example 3 and the comparative example in 3.5 wt.% NaCl solution were evaluated. Figures 5 and 6 As shown;

[0061] Figure 5 Impedance curves of Comparative Example and Example 1, Example 2, and Example 3 in 3.5 wt.% NaCl solution;

[0062] Figure 6 These are the moving point polarization curves of the comparative example and examples 1, 2, and 3 in 3.5 wt.% NaCl solution.

[0063] from Figure 5 It can be seen from the impedance curve that the peak values ​​of Example 1, Example 2, and Example 3 are significantly higher than that of the comparative example, showing better corrosion resistance, among which Example 1 shows the best corrosion resistance.

[0064] from Figure 6 It can be seen that the cathodic and anodic polarization curves of Example 1 are wider than those of the comparative example, Examples 2, and 3, showing a more pronounced passivation zone and better corrosion resistance. Furthermore, Example 1 also has a lower current density. Overall, Example 1 has better corrosion resistance than the comparative example, Examples 2, and 3.

[0065] As can be seen from the above examples, the method for preparing a corrosion-resistant CoCrNiTiN medium-entropy alloy nitride film provided by the present invention produces a dense structure and excellent corrosion resistance. By introducing nitrogen during the film preparation process, the film transitions from an amorphous to a crystalline structure, promoting an overall improvement in the film's corrosion resistance.

Claims

1. A method for preparing a corrosion-resistant CoCrNiTiN medium-entropy alloy nitride film, characterized in that The corrosion-resistant CoCrNiTiN medium-entropy alloy nitride film prepared by the preparation method has a dense structure, undulations of columnar crystals appear on the surface, and has good corrosion resistance; The preparation method is specifically completed according to the following steps:

1. Preprocessing: The surface of the pre-coated workpiece is ground with sandpaper, and then the workpiece is polished, and then the workpiece is ultrasonically cleaned and dried to obtain a pre-treated workpiece; The material of the workpiece described in step 1 is 42CrMo; In step 1, the surface of the pre-coated workpiece is polished using water sandpaper 240#, 600#, 800#, and metallographic sandpaper 400#, 600#, and 800# in sequence; The polishing process described in step 1 is as follows: polishing the workpiece for 1 minute using a polishing agent with a particle size of 2.5 μm; The ultrasonic cleaning described in step 1 is as follows: first, the workpiece is ultrasonically cleaned with petroleum ether for 10 minutes to remove oil stains on the surface of the workpiece, and then the workpiece is ultrasonically cleaned with anhydrous ethanol for 10 minutes to remove petroleum ether and other impurities on the surface of the workpiece; 2. Install the cobalt-chromium-nickel alloy target and the titanium target with equal atomic ratio on the target position of the DC power supply in sequence, load the pre-treated workpiece into the workpiece tray, close the vacuum chamber, and evacuate to 5×10 -3 Pa below; introduce argon gas into the vacuum chamber with a flow rate of 45sccm to maintain the pressure in the vacuum chamber at 0.5Pa, turn on the negative bias power supply, adjust the negative bias voltage to -50V, then turn on the power supply of the titanium target, pre-sputter for 10min, The power of the titanium target in step 2 was set to 60W; 3. After the pre-sputtering is completed, the power supply of the titanium target is turned off, and a mixture of nitrogen and argon is introduced to maintain the pressure in the vacuum chamber at 0.5 Pa. At the same time, the power supply of the cobalt-chromium-nickel alloy target and the power supply of the titanium target are turned on, and a negative bias voltage of -50 V is maintained. Magnetron sputtering is performed for 90 minutes, and an N-enhanced CoCrNiTiN medium-entropy nitride film is obtained on the surface of the workpiece, which is a corrosion-resistant CoCrNiTiN medium-entropy alloy nitride film. In step 3, the flow rate of nitrogen in the mixture of nitrogen and argon is 5 sccm, and the flow rate of argon is 45 sccm; In step 3, the power of the cobalt-chromium-nickel alloy target is 150W, and the power of the titanium target is set to 60W.

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