CN114645254B - TiAlMoNbW high-entropy alloy nitride film and preparation process thereof - Google Patents

Abstract

The invention _relates to _{a TiAlMoNbW} high- _{entropy alloy} nitride film and a preparation process thereof _. 6. d: 6-10, e: 5-9, x: 55-70, a+b+c+d+e+x=100, and the film is a columnar nanocrystalline structure with a grain size of 10- 70nm. The high-entropy alloy nitride film has high wear resistance, high corrosion resistance, and high mechanical properties.

Description

A TiAlMoNbW high-entropy alloy nitride thin film and its preparation process

technical field

The invention relates to the field of surface modification, in particular to a TiAlMoNbW high-entropy alloy nitride film and a preparation process thereof.

Background technique

High-entropy alloy is a new type of multi-principal alloy material composed of five or more elements in (nearly) equiatomic ratio. Since high-entropy alloys are different from traditional alloys in terms of design concept, equiatomic ratio or approximate Multiple elements with equal atomic ratio are the main components, which determines the different characteristics of high-entropy alloys and traditional alloys. However, compared with traditional alloy materials, the research and development of high-entropy alloys started late, the experimental basis is relatively weak, and the theoretical work is still not detailed enough. As a result, although this new type of alloy has great application potential, it is still difficult to achieve industrial production and application. Longer way to go.

The high-entropy alloy film developed on the basis of high-entropy alloys is a low-dimensional (micron-scale) high-entropy alloy material, which not only exhibits excellent properties similar to bulk high-entropy alloys, but also has certain properties (such as Hardness) is even better than bulk high-entropy alloys. At present, research in the field of high-entropy alloys is mainly based on as-cast alloys, while research on high-entropy alloy thin films is less, and high-entropy alloy nitride films are plated on the surface of the substrate to simultaneously improve its mechanical properties, wear resistance, There are fewer studies on corrosion resistance. And the commonly used method for preparing thin films is laser cladding, but it is prone to various defects, the surface is uneven, and the cracking sensitivity of the cladding layer is obvious, which limits the wide application of high-entropy alloy coatings.

Therefore, there is a need for a TiAlMoNbW high-entropy alloy nitride thin film with high wear resistance, high corrosion resistance, and high mechanical properties and a preparation process thereof.

Contents of the invention

The first technical problem to be solved by the present invention is to provide a TiAlMoNbW high-entropy alloy nitride film with high wear resistance, high corrosion resistance, and high mechanical properties in view of the current state of the art.

The second technical problem to be solved by the present invention is to provide a preparation process for the TiAlMoNbW high-entropy alloy nitride thin film.

The technical solution adopted by the present invention to solve the above technical problems is: the composition expression of this _TiAlMoNbW high-entropy alloy nitride thin film is Ti _a Al _b Mo _c Nb _d We N _x , a: 4～9, b: 4～ 8. c: 1~6, d: 6~10, e: 5~9, x: 55~70, a+b+c+d+e+x=100, and the film is nanocrystalline structure, crystal The particle size is 10-70nm. It is further preferred that the grain size is 20-40 nm.

Preferably, the value range is: a: 5-8, b: 5-7, c: 2-5, d: 7-9, e: 6-8, x: 60-65, a+b+c+ d+e+x=100.

Preferably, the thickness of the film is 500-1100 nm. More preferably, it is 60 to 900 nm.

Preferably, the thin film has a columnar nanocrystalline structure.

The film of the present invention is transformed from a TiAlMoNbW high-entropy alloy film with a BCC structure into a TiaAlbMocNbdWeNx high-entropy alloy nitride film with an FCC structure after the nitrogen gas is introduced into the film, and the crystal grain shape changes from needle-shaped to granular, and The grain orientations are mainly (200), (111), (220). Therefore preferably, the crystal structure of described thin film is FCC structure, and crystal orientation is (200), (111), (220) quantity accounts for more than 95% of crystal total amount, and the quantitative relation of each grain orientation is: ( 200)>(111)>(220), the quantity ratio between further preferred grain orientations is (200):(111):(220)=(8-12):(1-3):(0 -2). Choosing this kind of grain orientation can significantly improve the corrosion resistance while ensuring the overall performance.

Preferably, the nanohardness of the film is 19-27GPa, the modulus is 280-330GPa, and the density is above 95%.

In addition, the present invention also provides a preparation process for the TiAlMoNbW high-entropy alloy nitride thin film, comprising the following steps:

1. Prepare the target material: select the TiAlMoNbW high-entropy alloy target material containing five elements: Ti, Al, Mo, Nb, and W. The atomic ratio of its constituent elements is Ti:Al:Mo:Nb:W=1:1:1: 1:1at.%.

2. Prepare the substrate: the present invention can choose any metal substrate whose surface properties are to be improved, preferably CSS-42L steel, H13 steel, H11 steel, copper, etc.

3. Thin film deposited by sputtering:

3a. Pre-evacuate to 0.8×10-1～1.5×10-1Pa, continue to evacuate to 2.0×10-3～3.0×10-3Pa, and inject the mixed gas of argon and nitrogen as the working gas;

3b. Turn on the negative bias, clean the target, turn off the bias, adjust the working pressure, pre-sputter the target, and remove the oxides and pollutants on the surface of the high-entropy alloy target;

3c. Sputtering: the sputtering power is 80-350W, the substrate temperature is 20-350°C, and the substrate is sputtered. After the sputtering is finished, a sample deposited with a high-entropy alloy nitride thin film is obtained. The sputtering power changes the kinetic energy and sputtering rate of the sputtered particles by affecting the energy of the incident ions, and further controls the deposition rate and preferred orientation of the film; as the sputtering power increases, the sputtering rate will continue to increase, but when the sputtering rate When it is too large, the deposition rate of the target atoms is too fast to react with the reaction gas, which will eventually affect the composition and performance of the film; the preferred sputtering power of the present invention is 80-350W. The substrate temperature will change the cooling rate during the film deposition process, which will have a greater impact on the crystal structure, growth mode and film-substrate bonding force of the film; increasing the substrate temperature can increase the activation reaction of nitrogen atoms and metal atoms, while cooling The reduction of the speed will increase its diffusion rate and particle size; a lower substrate temperature will result in a looser film and cause the film to fall off, and an excessively high substrate temperature will also cause the film to shrink due to the difference in thermal expansion coefficient between the substrate and the film. The substrate binding force decreases; the substrate temperature also has a significant impact on the phase structure of HEFs. In addition, with the increase of the substrate temperature, the grain size becomes larger, which is because the increase of the substrate temperature improves the adsorption capacity of atoms and surface mobility, crystal grains are easy to grow; the preferred substrate temperature of the present invention is 20-350°C.

Preferably, the size of the substrate in step 2 is 8-12mm×8mm˜12mm×2-6mm.

Preferably, the substrate in step 2 is pre-treated: the surface of the substrate is ground to 1200-1700# sandpaper and polished, first ultrasonically treated with acetone for 30-50 minutes, then ultrasonically treated with alcohol for 10-30 minutes, and cleaned in deionized water Perform ultrasonic cleaning for 10-30 minutes, then put them into alcohol for ultrasonic cleaning for 10-30 minutes, and set the temperature at 20°C, and finally put them into a vacuum drying oven for drying at 100-140°C.

Preferably, the working gas in step 3a is 50% argon and 50% nitrogen. The argon gas is used as a protective gas, and the nitrogen gas is used for the formation of the nitride film. The working atmosphere of magnetron sputtering in the present invention is composed of sputtering gas argon and reaction gas nitrogen. When the total pressure is constant, with the increase of the partial pressure of the reaction gas, the Ar content will be relatively low, resulting in sputtering production. Therefore, the sputtering rate will continue to decrease. Properly reducing the sputtering rate can provide more time for the migration of surface particles, refine the grains, and reduce the roughness of the film; in addition, due to the solid solution strengthening Effect and dense film structure, the hardness of the nitride film increases with the increase of nitrogen content. However, as the flow rate of nitrogen continues to increase, the content of nitrogen atoms is too high, and the number of metal nitride phases in the film increases rapidly. The above trends lead to the formation of defects such as columnar coarse grains and pores in the film, resulting in a decrease in film hardness and elastic modulus. Increase; at the same time, when the partial pressure of the reactant gas is too large, the vacancies in the film will increase, and this defect will reduce the performance of the film. The preferred working gas of the present invention is 50% argon and 50% nitrogen.

Preferably, the negative bias in step 3b is 12-22V, and the cleaning time is 3-10 minutes.

Preferably, the working pressure in step 3b is 0.5-1 Pa, and the pre-sputtering time is 10-30 min.

Compared with the prior art, the present invention has the advantages of:

1. Ti, Mo, Nb, and W are high melting point elements located in Group 4 to Group 6 (commonly known as refractory metals) in the periodic table of elements. The four elements have similar atomic radii and properties, and are easier to form stable solid solutions alloy, so it can form a dense columnar crystal structure together with N element.

2. Since the density of TiMoNbW alloy is as high as 13.75g/cm ³ , adding low-density element Al to the alloy reduces the overall density, and adding Al element can cause lattice distortion, refine grain, and play a role of solid solution strengthening function to improve its strength and hardness; the interstitial element nitrogen is introduced during the film preparation process to fill the gaps in the crystal lattice, refine the grains, reduce the surface roughness, and obtain a dense columnar nanocrystalline structure; and Ti, Al, Mo, and Nb, as strong nitride-forming elements, are easy to combine with nitrogen to form nitrides, so that the crystal structure of the alloy film changes from a BCC structure to a high-hardness FCC structure. Due to the dense columnar nanocrystalline structure and the crystal structure is FCC, the mechanical properties of the film are further improved. The nanohardness increases from 11.42GPa of the alloy film to 25.7GPa of the nitride film, and the modulus increases from 233.1GPa of the alloy film. to 313.6GPa of the nitride film. At the same time, Mo and W elements will form a lubricating oxide film on the surface of the nitride coating, which reduces the friction resistance during the sliding process and further improves the wear resistance. The wear volume decreases from 2.14×10 ⁹ of the substrate to 0.436×10 ⁹ cm ³ .

3, the high-entropy alloy nitride thin film that the present invention adopts, because the number of elements in the Ti _a Al _b Mo _c Nb _d We _e high-entropy alloy is enough, cause the mixed entropy ratio of system to form the entropy of intermetallic compound to become larger, thereby Inhibit the appearance of intermetallic compounds, so that the Ti _a Al _b Mo _{c Nb d} We N _x high-entropy alloy nitride film forms a simple FCC solid solution structure, the composition distribution is uniform, the structure is compact, and the formation of the original battery is reduced. The corrosion tendency is reduced, and Al, Nb, and W are corrosion-resistant elements, which promote the formation of a passivation film and can effectively improve the corrosion resistance of the substrate. In NaCl corrosion medium, the corrosion rate of the base steel decreased from 0.493mpy to 0.03mpy, and the self-corrosion current decreased from 1544nA to 103.48nA.

4, the present invention adopts magnetron sputtering method to carry out thin film preparation: (a) the thin film that uses magnetron sputtering technology to obtain is relatively uniform, the performance of equipment is very stable, repeatability is strong, is very suitable for large-scale production; (b) magnetic The controlled equipment is easy to operate and the process parameters are controllable. Films with different performance requirements can be obtained by controlling parameters such as sputtering power, substrate temperature, and working gas ratio; (c) high-entropy alloys prepared by magnetron sputtering Films generally have residual compressive stress and a dense structure, which is conducive to the improvement of film performance.

Description of drawings

Fig. 1 is the SEM sectional view of the Ti _a Al _b Mo _{c Nb d} We N _x high-entropy alloy nitride film of embodiment 1 of the present invention;

Fig. 2 is the SEM surface topography figure of embodiment 1 of the present invention Ti _a Al _b Mo _{c Nb d} We N _x high-entropy alloy nitride film;

Fig. 3 is the SEM surface topography picture of TiAlMoNbW high-entropy alloy thin film;

Fig. 4 is the XRD spectrum of embodiment 1 of the present invention Ti _a Al _b Mo _{c Nb d} We N _x high-entropy alloy nitride film;

Fig. 5 is the friction coefficient graph of embodiment 1 of the present invention Ti _a Al _b Mo _{c Nb d} We N _x high-entropy alloy nitride film;

Fig. 6 is the wear cross-sectional contour figure of Ti _a Al _b Mo _{c Nb d} We N _x high-entropy alloy nitride film of embodiment 1 of the present invention;

Fig. 7 is the polarization curve of Ti _a Al _b Mo _{c Nb d} We N _x high-entropy alloy nitride thin film in 1mol/L sulfuric acid corrosion medium of embodiment 1 of the present invention;

Fig. 8 is the Nyquist curve graph obtained by Ti _a Al _b Mo _{c Nb d} We N _x high-entropy alloy nitride film impedance test of embodiment 1 of the present invention;

Fig. 9 is a Bode curve obtained from the resistance test of Ti _a Al _b Mo _{c Nb d} We N _x high-entropy alloy nitride film in Example 1 of the present invention.

Detailed ways

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. Those who do not indicate the specific conditions in the examples are carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used were not indicated by the manufacturer, and they were all conventional products that could be purchased from the market. The base materials of the following embodiments are all CSS-42L steels. In addition, H13 steel, H11 steel, copper and other base materials also have similar technical effects.

Example 1:

1. Prepare the target material: select a disc-shaped TiAlMoNbW high-entropy alloy target material containing five elements: Ti, Al, Mo, Nb, and W. The atomic ratio of its constituent elements is Ti:Al:Mo:Nb:W=1:1 :1:1:1at.%. The diameter of the target is 101.6mm, and the thickness of the target is 3mm. The preparation of the target in this embodiment specifically includes the following steps,

a. Prepare Ti, Al, Mo, Nb metal blocks and W metal powder according to the composition ratio;

b. Master alloy refining:

b1. First add Ti and Al metal blocks with a melting point lower than 2000K and an atomic ratio of 1:1 for smelting to obtain a TiAl master alloy;

b2. Then add Mo and Nb metal blocks with a melting point lower than 3000K and an atomic ratio of 1:1 for smelting to obtain a TiAlMoNb master alloy;

c. Preparation of TiAlMoNb master alloy powder: crush and refine the TiAlMoNb master alloy to obtain 150-300 mesh metal powder;

d. Preparation of TiAlMoNbW high-entropy alloy powder: add 300-1000 mesh W metal powder to TiAlMoNb master alloy powder, and mix evenly to obtain TiAlMoNbW high-entropy alloy powder;

e. The TiAlMoNbW high-entropy alloy powder is prepared through a molding process to obtain a TiAlMoNbW high-entropy alloy target.

2. Prepare the substrate: CSS-42L steel is selected in this embodiment, and the preparation of the substrate in this embodiment specifically includes the following steps,

2a. Choose electrolytic iron (Fe), 99% chromium (Cr), 99.95% molybdenum (Mo), 99.7% vanadium (V), 99.95% nickel (Ni), 99.5% Silicon (Si), 99.7% manganese (Mn) and 99.9% graphite (C), are ultrasonically cleaned with acetone and dried at 120°C;

2b. Three master alloys of Fe-4.3C, Fe-20Si and Fe-50Mn were prepared by vacuum induction melting furnace;

2c. After the intermediate alloy is smelted, use grinding wheel grinding and lathe turning to remove the oxide skin and impurities on the alloy surface, and then melt the CSS-42L steel ingot according to the ratio;

2d. Cut the smelted CSS-42L steel ingot into a 10mm×10mm×4mm block with wire cutting equipment, polish the surface to 1500# sandpaper and polish, perform ultrasonic cleaning for 15min, put it in a vacuum oven to dry, and the temperature Set to 120°C;

2e. Put the dried CSS-42L steel substrate and high-entropy alloy target on the sample stage and evaporation source in the vacuum chamber of the DC magnetron sputtering equipment.

3. Thin film deposited by sputtering:

3a. Close the vacuum chamber of the DC magnetron sputtering equipment, turn on the mechanical pump, and turn on the pre-vacuumization state of the vacuum chamber. When the air pressure reaches 1.0×10 ^-1 Pa, open the molecular pump and the flapper valve for further vacuuming. Evacuate to 2.5 × 10 ^-3 Pa, based on the goal of preparing the nitride film of the present invention, feed a mixed gas of 60% high-purity argon and 40% high-purity nitrogen as the working gas;

3b. Close the sample stage valve and the evaporation source valve, turn on the 15V substrate negative bias, and clean the target for 5 minutes to remove the pollutants attached to the surface of the high-entropy alloy target, close the bias, and adjust the working pressure to 0.8 Pa, pre-sputtering the target for 10-20 minutes to remove the oxides on the surface of the high-entropy alloy target;

3c. Continue to rotate the sample stage, open the valve of the sample stage and the evaporation valve for sputtering, the sputtering power is 100W, the substrate temperature is 27°C, the sputtering time is 4651s, after the sputtering is over, take out the deposited high-entropy alloy nitride film sample.

The composition expression of the high-entropy alloy nitride thin film of this embodiment is Ti _a Al _b Mo _c Nb _d We N _x , where a=8, b=7, c=3, d=10, _e =7, x =65, a+b+c+d+e+x=100. The grain distribution of the thin film in this embodiment is uniform, all are columnar nanocrystals, the thickness is 544nm, the grain size is 10-58nm, the density is 98%, the nanohardness is 20.53GPa, and the modulus is 280GPa, as shown in Figure 1 . And as shown in Figure 2 is the SEM surface morphology of the Ti _a Al _b Mo _c Nb _d We N _x high-entropy alloy nitride film, compared with the _TiAlMoNbW high-entropy alloy film shown in Figure 3, and with other tests , the film is converted from the _TiAlMoNbW high-entropy alloy film with the BCC structure to the Ti _a Al _b Mo _c Nb _d We N _x high-entropy alloy nitride film with the FCC structure after the nitrogen gas is introduced into the film, and its grain morphology has changed from the needle leaf The transition from granular to granular, its grain orientations are mainly (200), (111), (220), and the number of grain orientations (200), (111), (220) accounts for more than 95% of the total crystals , and the quantity ratio between each grain orientation is (200):(111):(220)=10:2:1.

Fig. 4 is the XRD pattern of the thin film of this embodiment, which is a single-phase FCC solid solution structure after jade analysis.

Fig. 5 is the reciprocating friction friction coefficient curve of present embodiment sample and substrate, can see that the friction coefficient of substrate CSS-42L steel is 0.73 according to curve, and the friction coefficient of present embodiment film is 0.61, illustrates that the film of the present invention has good wear resistance.

Figure 6 is a schematic diagram of the reciprocating friction and wear profile between the sample and the substrate in this embodiment. According to the curve, it can be seen that the wear depth of the nitride film is about 1/3 of that of the substrate steel, showing good wear resistance.

Fig. 7 is the potentiodynamic polarization curve of the sample and the substrate in 1mol/L sulfuric acid corrosion solution of this embodiment. It can be seen from the figure that the sample has a passivation zone in the sulfuric acid corrosion solution, but the CSS- The passivation zone of 42L steel appeared later than that of the Ti _a Al _b Mo _{c Nb d} We N _x high-entropy alloy thin film sample, indicating that a stable passivation film was formed on the surface during the polarization process, which can effectively prevent acid radicals from entering the matrix. The pitting corrosion resistance of the high-entropy alloy film is better than that of CSS-42L steel.

Figures 8-9 are the Nyquist curves and Bode curves obtained by the impedance test of the samples of this example and the substrate in 1mol/L sulfuric acid corrosive solution respectively. It can be seen from the figures that both the film and the base steel are double-arc spectra . In the Nyquist spectrum, the radius of the semicircular arc is related to the polarization ability of the passivation layer, and the larger the radius, the stronger the polarization ability of the passivation layer. The Nyquist curve radius of the high-entropy alloy nitride film is much higher than that of the base CSS-42L steel. It can be seen from the Bode curve that the impedance modulus of the nitride film is about 15 times that of the CSS-42L base steel, showing the good corrosion resistance of the film.

Example 2:

1. Prepare the target material: select a disc-shaped TiAlMoNbW high-entropy alloy target material containing five elements: Ti, Al, Mo, Nb, and W. The atomic ratio of its constituent elements is Ti:Al:Mo:Nb:W=1:1 :1:1:1at.%. The diameter of the target is 101.6mm, and the thickness of the target is 3mm. The preparation of the target in this embodiment specifically includes the following steps,

a. Prepare Ti, Al, Mo, Nb metal blocks and W metal powder according to the composition ratio;

b. Master alloy refining:

b1. First add Ti and Al metal blocks with a melting point lower than 2000K and an atomic ratio of 1:1 for smelting to obtain a TiAl master alloy;

b2. Then add Mo and Nb metal blocks with a melting point lower than 3000K and an atomic ratio of 1:1 for smelting to obtain a TiAlMoNb master alloy;

c. Preparation of TiAlMoNb master alloy powder: crush and refine the TiAlMoNb master alloy to obtain 150-300 mesh metal powder;

d. Preparation of TiAlMoNbW high-entropy alloy powder: add 300-1000 mesh W metal powder to TiAlMoNb master alloy powder, and mix evenly to obtain TiAlMoNbW high-entropy alloy powder;

e. The TiAlMoNbW high-entropy alloy powder is prepared through a molding process to obtain a TiAlMoNbW high-entropy alloy target.

2. Prepare the substrate: CSS-42L steel is selected in this embodiment, and the preparation of the substrate in this embodiment specifically includes the following steps,

2a. Choose electrolytic iron (Fe), 99% chromium (Cr), 99.95% molybdenum (Mo), 99.7% vanadium (V), 99.95% nickel (Ni), 99.5% Silicon (Si), 99.7% manganese (Mn) and 99.9% graphite (C), are ultrasonically cleaned with acetone and dried at 120°C;

2b. Three master alloys of Fe-4.3C, Fe-20Si and Fe-50Mn were prepared by vacuum induction melting furnace;

2c. After the intermediate alloy is smelted, use grinding wheel grinding and lathe turning to remove the oxide skin and impurities on the alloy surface, and then melt the CSS-42L steel ingot according to the ratio;

2d. Cut the smelted CSS-42L steel ingot into a 10mm×10mm×4mm block with wire cutting equipment, polish the surface to 1500# sandpaper and polish, perform ultrasonic cleaning for 15min, put it in a vacuum oven to dry, and the temperature Set to 120°C;

2e. Put the dried CSS-42L steel substrate and high-entropy alloy target on the sample stage and evaporation source in the vacuum chamber of the DC magnetron sputtering equipment.

3. Thin film deposited by sputtering:

3a. Close the vacuum chamber of the DC magnetron sputtering equipment, turn on the mechanical pump, and turn on the pre-vacuumization state of the vacuum chamber. When the air pressure reaches 1.0×10 ^-1 Pa, open the molecular pump and the flapper valve for further vacuuming. Evacuate to 2.5 × 10 ^-3 Pa, based on the goal of preparing the nitride film of the present invention, feed a mixed gas of 50% high-purity argon and 50% high-purity nitrogen as the working gas;

3b. Close the sample stage valve and the evaporation source valve, turn on the 15V substrate negative bias, and clean the target for 5 minutes to remove the pollutants attached to the surface of the high-entropy alloy target, close the bias, and adjust the working pressure to 0.8 Pa, pre-sputtering the target for 10-20 minutes to remove the oxides on the surface of the high-entropy alloy target;

3c. Continue to rotate the sample stage, open the valve of the sample stage and the evaporation valve for sputtering, the sputtering power is 200W, the substrate temperature is 177°C, and the sputtering time is 2325s. After the sputtering is over, take out the deposited high-entropy alloy nitride film sample.

The composition expression of the high-entropy alloy nitride thin film of this embodiment is Ti _a Al _b Mo _c Nb _d We N _x , where a=9, b=5, c=1, d=8, _e =8, x =69, a+b+c+d+e+x=100. The grain distribution of the thin film in this embodiment is uniform, all are columnar nanocrystals, the thickness is 611nm, the grain size is 25-70nm, the density is 96%, the nanohardness is 21.76GPa, the modulus is 286.3GPa, and the film is FCC structure , the grain orientations are mainly (200), (111), (220), and the number of crystal orientations (200), (111), (220) accounts for more than 95% of the total crystals, and each grain orientation The quantity ratio between them is (200):(111):(220)=8:3:1.

The reciprocating friction experiment was carried out between the sample and the substrate in this embodiment, and it was found that the friction coefficient of the substrate was 0.73, while the friction coefficient of the nitride film was 0.62, showing that the film of the present invention has good wear resistance.

The sample and substrate of this embodiment are carried out in the electrochemical experiment in NaCl corrosion medium, the corrosion rate of CSS-42L steel is 0.439mpy, and the self-corrosion current is 1544nA, and the thin film corrosion rate of the present invention is 0.033mpy, self-corrosion The current is 103.48nA. It is found by comparison that the film can effectively reduce the corrosion tendency of the base steel and improve its corrosion resistance.

Example 3:

1. Prepare the target material: select a disc-shaped TiAlMoNbW high-entropy alloy target material containing five elements: Ti, Al, Mo, Nb, and W. The atomic ratio of its constituent elements is Ti:Al:Mo:Nb:W=1:1 :1:1:1at.%. The diameter of the target is 101.6mm, and the thickness of the target is 3mm. The preparation of the target in this embodiment specifically includes the following steps,

a. Prepare Ti, Al, Mo, Nb metal blocks and W metal powder according to the composition ratio;

b. Master alloy refining:

b1. First add Ti and Al metal blocks with a melting point lower than 2000K and an atomic ratio of 1:1 for smelting to obtain a TiAl master alloy;

b2. Then add Mo and Nb metal blocks with a melting point lower than 3000K and an atomic ratio of 1:1 for smelting to obtain a TiAlMoNb master alloy;

c. Preparation of TiAlMoNb master alloy powder: crush and refine the TiAlMoNb master alloy to obtain 150-300 mesh metal powder;

d. Preparation of TiAlMoNbW high-entropy alloy powder: add 300-1000 mesh W metal powder to TiAlMoNb master alloy powder, and mix evenly to obtain TiAlMoNbW high-entropy alloy powder;

e. The TiAlMoNbW high-entropy alloy powder is prepared through a molding process to obtain a TiAlMoNbW high-entropy alloy target.

2. Prepare the substrate: CSS-42L steel is selected in this embodiment, and the preparation of the substrate in this embodiment specifically includes the following steps,

2a. Choose electrolytic iron (Fe), 99% chromium (Cr), 99.95% molybdenum (Mo), 99.7% vanadium (V), 99.95% nickel (Ni), 99.5% Silicon (Si), 99.7% manganese (Mn) and 99.9% graphite (C), are ultrasonically cleaned with acetone and dried at 120°C;

2b. Three master alloys of Fe-4.3C, Fe-20Si and Fe-50Mn were prepared by vacuum induction melting furnace;

2c. After the intermediate alloy is smelted, use grinding wheel grinding and lathe turning to remove the oxide skin and impurities on the alloy surface, and then melt the CSS-42L steel ingot according to the ratio;

2d. Cut the smelted CSS-42L steel ingot into a 10mm×10mm×4mm block with wire cutting equipment, polish the surface to 1500# sandpaper and polish, perform ultrasonic cleaning for 15min, put it in a vacuum oven to dry, and the temperature Set to 120°C;

2e. Put the dried CSS-42L steel substrate and high-entropy alloy target on the sample stage and evaporation source in the vacuum chamber of the DC magnetron sputtering equipment.

3. Thin film deposited by sputtering:

3a. Close the vacuum chamber of the DC magnetron sputtering equipment, turn on the mechanical pump, and turn on the pre-vacuumization state of the vacuum chamber. When the air pressure reaches 1.0×10 ^-1 Pa, open the molecular pump and the flapper valve for further vacuuming. Vacuumize to 2.5 × 10 ^-3 Pa, based on the goal of preparing the nitride film of the present invention, feed a mixed gas of 40% high-purity argon and 60% high-purity nitrogen as the working gas;

3b. Close the sample stage valve and the evaporation source valve, turn on the 15V substrate negative bias, and clean the target for 5 minutes to remove the pollutants attached to the surface of the high-entropy alloy target, close the bias, and adjust the working pressure to 0.8 Pa, pre-sputtering the target for 10-20 minutes to remove the oxides on the surface of the high-entropy alloy target;

3c. Continue to rotate the sample stage, open the valve of the sample stage and the evaporation valve for sputtering, the sputtering power is 300W, the substrate temperature is 327°C, the sputtering time is 1550s, after the sputtering is over, take out the deposited high-entropy alloy nitride film sample.

The composition expression of the high-entropy alloy nitride thin film of this embodiment is Ti _a Al _b Mo _c Nb _d We N _x , where a=8, b=5, c=2, d=7, _e =8, x =70, a+b+c+d+e+x=100. The grain distribution of the thin film in this embodiment is uniform, all are columnar nanocrystals, the thickness is 643nm, the grain size is 23-66nm, the density is 95%, the nanohardness is 25.7GPa, the modulus is 313.6GPa, and the film is a single phase FCC structure, its grain orientation is mainly (200), (111), (220), and the number of crystal orientations (200), (111), (220) accounts for more than 95% of the total crystals, and each grain The quantitative ratio between the orientations is (200):(111):(220)=12:1:0.8.

The sample of this embodiment and the substrate carry out the reciprocating friction experiment to obtain the friction coefficient, the friction coefficient of the substrate CSS-42L steel is 0.73, and the friction coefficient of the nitride film is 0.59, showing the good wear resistance of the film of the present invention .

The sample and substrate of this embodiment are carried out electrochemical experiments in NaCl corrosion medium, the corrosion rate of CSS-42L steel is 0.4033mpy, and the self-corrosion current is 936.58nA, and the thin film corrosion rate of the present invention is 0.021mpy, self-corrosion The corrosion current is 228.72nA. It is found by comparison that the film can effectively reduce the corrosion tendency of the base steel and improve its corrosion resistance.

The technical means disclosed in the solutions of the present invention are not limited to the technical means disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be pointed out that for those skilled in the art, some improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also regarded as the protection scope of the present invention.

Claims (10)

1. A _TiAlMoNbW high-entropy alloy nitride film, characterized in that: the composition expression is Ti _a Al _b Mo _c Nb _d We N _x , a: 4~9, b: 4~8, c: 1~6 , d: 6-10, e: 5-9, x: 55-70, a+b+c+d+e+x=100, and the film has a nanocrystalline structure with a grain size of 10-70nm; The TiAlMoNbW high-entropy alloy nitride thin film is prepared by the following steps: (1) Prepare the target material: select a TiAlMoNbW high-entropy alloy target material containing five elements: Ti, Al, Mo, Nb, and W, and the atomic ratio of its constituent elements is Ti:Al:Mo:Nb:W=1:1:1 :1:1at.%; (2) Prepare the substrate; (3) Thin films deposited by sputtering. 2. The TiAlMoNbW high-entropy alloy nitride thin film according to claim 1, characterized in that the value ranges are: a: 5-8, b: 5-7, c: 2-5, d: 7-9, e: 6-8, x: 60-65, a+b+c+d+e+x=100. 3. The TiAlMoNbW high-entropy alloy nitride thin film according to claim 1, characterized in that the thickness of the thin film is 500-1100 nm. 4. The TiAlMoNbW high-entropy alloy nitride thin film according to claim 1, characterized in that: the thin film has a columnar nanocrystalline structure. 5. The TiAlMoNbW high-entropy alloy nitride thin film according to claim 1, characterized in that: the crystal structure of the thin film is an FCC structure, and the crystal orientations are (200), (111), (220) in the total number of crystals The amount is more than 95%, and the number ratio between each grain orientation is (200):(111):(220)=(8-12):(1-3):(0-2). 6 . The TiAlMoNbW high-entropy alloy nitride thin film according to claim 1 , wherein the nanohardness of the thin film is 19-27 GPa, the modulus is 280-330 GPa, and the density is above 95%. 7. The preparation process for preparing the TiAlMoNbW high-entropy alloy nitride film according to any one of claims 1 to 6, is characterized in that it comprises the following steps: (1) Prepare the target material: select a TiAlMoNbW high-entropy alloy target material containing five elements: Ti, Al, Mo, Nb, and W, and the atomic ratio of its constituent elements is Ti:Al:Mo:Nb:W=1:1:1 :1:1at.%; (2) Prepare the substrate; (3) Sputtering deposited film: 3a. Pre-evacuate to 0.8×10 ^-1 ~ 1.5×10 ^-1 Pa, continue to evacuate to 2.0×10 ^-3 ~ 3.0×10 ^-3 Pa, and inject a mixture of argon and nitrogen as the working gas; 3b. Turn on the negative bias, clean the target, turn off the bias, adjust the working pressure, pre-sputter the target, and remove the oxides and pollutants on the surface of the high-entropy alloy target; 3c. Sputtering: the sputtering power is 80-350W, the substrate temperature is 20-350°C, and the substrate is sputtered. After the sputtering is finished, a sample deposited with a high-entropy alloy nitride thin film is obtained. 8. The process for preparing TiAlMoNbW high-entropy alloy nitride film according to claim 7, characterized in that: the working gas in the step 3a is 50% argon and 50% nitrogen. 9 . The preparation process of TiAlMoNbW high-entropy alloy nitride film according to claim 7 , characterized in that: the negative bias voltage in the step 3b is 12-22V, and the cleaning time is 3-10 minutes. 10. The process for preparing TiAlMoNbW high-entropy alloy nitride film according to claim 7, characterized in that: the working pressure in step 3b is 0.5-1 Pa, and the pre-sputtering time is 10-30 min.

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