A preparation method of a rare earth modified corrosion-resistant high-entropy alloy, an alloy prepared by the method and applications thereof

Abstract

The application discloses a preparation method of a rare earth modified corrosion-resistant high-entropy alloy, an alloy prepared by the method and application of the alloy. The preparation method comprises the following steps: (1) weighing copper powder (Cu), titanium powder (Ti), chromium powder (Cr), aluminum powder (Al) and nickel powder (Ni) according to a certain proportion, and weighing one of intermediate alloy powders CeNi, LaNi, YNi and PrNi; (2) adding the above raw materials into a plasma ball mill to perform high-energy mechanical mixing, wherein the ball-to-material ratio is 10-15:1; (3) pressing the mixed alloy powder into small round ingots; and (4) sintering at 800-1000 DEG C for 8-10 h under the protection of argon, so that the elements are fully diffused and tend to form a saturated single-phase solid solution, namely, the rare earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiRe is prepared, wherein Re is any one of Ce, La, Y and Pr. The rare earth modified corrosion-resistant high-entropy alloy prepared by the application has excellent corrosion resistance in a marine environment.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of materials, and particularly relates to a preparation method of a rare earth modified corrosion-resistant high-entropy alloy, an alloy prepared by the method, and application of the alloy. BACKGROUND

[0002] High-entropy alloys (HEAs) are a new type of material with excellent performance. Since their inception, they have attracted widespread attention from the scientific community due to their unique composition and characteristics. Corrosion-resistant rare earth high-entropy alloys are a type of alloy material with significant corrosion resistance. The background technology involves multiple aspects, including alloy design philosophy, constituent elements, preparation process, performance characteristics, and application fields.

[0003] In terms of design philosophy, the design philosophy of corrosion-resistant rare earth high-entropy alloys is derived from the challenge to traditional alloy theory. Traditional alloys usually have one or two metal elements as the main component, with a small amount of other elements added to improve performance. High-entropy alloys, on the other hand, use five or more main elements in equal atomic ratio or near equal atomic ratio to form a multi-main element alloy. And introduce the ball milling of plasma ball milling mixing, this design philosophy makes the high-entropy alloy has higher mixing entropy and simpler microstructure, so as to show excellent mechanical properties and corrosion resistance.

[0004] In contrast to traditional alloys that typically contain only one or two basic elements, corrosion-resistant rare earth high-entropy alloys usually include rare earth elements and Cr, Ni, Al, Cu, and other elements with passivation properties. Rare earth elements have unique electronic structure and chemical properties, which can significantly improve the corrosion resistance of the alloy. At the same time, Cr, Ni, Al, Cu and other elements form a dense passivation film in the alloy, effectively preventing the corrosion of corrosive media. In addition, according to the needs of specific application scenarios, other elements can be added to further optimize the performance of the alloy.

[0005] It is worth mentioning that the rare earth modified corrosion-resistant high-entropy alloy of the present design incorporates rare earth elements La, Ce, Y, and Pr. Light rare earth not only has a low cost, but also has excellent corrosion resistance. During the corrosion process, the rare earth element Ce can cleverly reduce the corrosion current, effectively broaden the passivation potential interval, and promote the formation of stable Ce2O3 / Ce(OH)3 conversion film on the alloy surface. This conversion film is like a strong "defense line" that greatly enhances the resistance to charge and mass transfer, thereby significantly reducing the corrosion rate and providing the alloy with "protective armor". In summary, rare earth high-entropy alloys have unique advantages and have a broad application prospect in marine corrosion-resistant materials, and are expected to bring about new changes in the industry. SUMMARY

[0006] In view of the problems in the prior art, the present application aims to provide a rare earth modified corrosion-resistant high-entropy alloy and a preparation method thereof, the prepared high-entropy alloy has excellent corrosion resistance, and the preparation process is simple and has high production efficiency.

[0007] The technical scheme adopted by the present application is:

[0008] A preparation method of a rare earth modified corrosion-resistant high-entropy alloy, comprising the following steps:

[0009] (1) A certain proportion of copper powder (Cu), titanium powder (Ti), chromium powder (Cr), aluminum powder (Al), nickel powder (Ni) and intermediate alloy powder is weighed, and the intermediate alloy powder is one of CeNi, LaNi, YNi and PrNi;

[0010] (2) The above raw materials are added to the plasma ball mill for high-energy mechanical mixing, wherein the ball-to-material ratio is 10-15:1;

[0011] (3) The mixed powder is pressed into small round ingots;

[0012] (4) Under the protection of argon, the small round ingots are sintered at 800-1000℃ for 8-10h, so that the elements are fully diffused and tend to form a saturated single-phase solid solution, i.e. a rare earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiRe is prepared, wherein Re is any one of Ce, La, Y and Pr.

[0013] In the step (1), each raw material is weighed according to a molar ratio of 1:1:1:1:1:1; the molar ratio of the two elements in the intermediate alloy powder is 1:1.

[0014] In the step (2), the rotation speed of the plasma ball mill is 1000rpm-1300rpm, the power is 7-9kW, and the mixing time is 10-15h;

[0015] In the step (3), the alloy cylinders are pressed into the glove box by the DY-20 tablet press;

[0016] In the step (3), stainless steel ball milling beads are used in the plasma ball mill, wherein the beads with a diameter of 16mm account for 10-25wt.%, the beads with a diameter of 10mm account for 10-25wt.%, and the beads with a diameter of 3-7mm account for 50-70wt.%, the ball milling beads and metal powder are poured into the plasma ball mill and filled with argon for protection, and the plasma mechanical mixing is carried out;

[0017] In the step (3), 3g~5g of the powder is weighed and poured into the mold during pressing, and the alloy cylinders with a diameter of 10-20mm and a thickness of 2-4mm are pressed under a pressure of 20-40Mpa.

[0018] The sintering step of the step (4) is cooled by furnace cooling.

[0019] Preferably, one or more of manganese powder (Mn), iron powder (Fe), and cobalt powder (Co) is added to the raw material.

[0020] The rare earth modified corrosion-resistant high-entropy alloy obtained by the preparation method has CuTiCrAlNiRe, and Re is any one of Ce, La, Y, and Pr.

[0021] The rare earth modified corrosion-resistant high-entropy alloy can be sputtered on the surface of a material as a target to form a protective layer. Advantages

[0022] The rare earth modified corrosion-resistant high-entropy alloy has excellent corrosion resistance, and the addition of rare earth elements improves the corrosion resistance of the high-entropy alloy. The rare earth elements are added in the form of an intermediate alloy to avoid oxidation when pure rare earth elements are added. The mixing is performed by a plasma ball mill to provide diffusion activation energy in the powder metallurgy process. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a finished product diagram of the sintered CuTiCrAlNiCe rare earth modified corrosion-resistant high-entropy alloy obtained by the method of Example 1.

[0024] Figure 2 is an SEM diagram of the rare earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiCe in Example 1.

[0025] Figure 3 is an SEM diagram of the rare earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiY in Example 2.

[0026] Figure 4 is an XRD diagram of the rare earth modified corrosion-resistant high-entropy alloy in Examples 1-3.

[0027] Figure 5 is a Tafel curve of the rare earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiCe in Example 1.

[0028] Figure 6 is an AC impedance curve of the rare earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiCe in Example 1.

[0029] Figure 7 is a DSC curve of the rare earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiCe in Example 1.

[0030] Figure 8Picture of full immersion experiment of the rare earth modified corrosion resistant high-entropy alloy of Example 1 in 1 mol / L NaCl solution.

[0031] Figure 9 Picture of salt spray experiment of the rare earth modified corrosion resistant high-entropy alloy of Example 1 in 1 mol / L NaCl solution. DETAILED DESCRIPTION

[0032] In order to further understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0033] Unless otherwise specified, the reagents involved in the embodiments of the present application are all commercially available and can be purchased through commercial channels.

[0034] Example 1

[0035] Aluminum powder, chromium powder, copper powder, titanium powder, nickel powder and cerium-nickel intermediate alloy powder with an average particle size of 75-100 μm were weighed according to a molar ratio of 1:1:1:1:1:1, and the purity of the metal powders was all above 99.99%. The weighed metal powders were poured into a stainless steel plasma ball mill, stainless steel ball milling beads were weighed according to a ball-to-powder ratio of 10:1, and the ball milling beads were poured into the plasma ball mill. The ball milling jar in the ball mill was filled with argon for protection; wherein the 16 mm diameter beads accounted for 20%, the 10 mm diameter beads accounted for 25%, and the 5 mm diameter beads accounted for 55%. The planetary ball mill was mechanically mixed for 10 h at 1300 rpm power 8 kW. The mixed alloy powder was weighed at 4 g and poured into a mold, and a powder tablet press was used to press into a cylinder with a diameter of 15 mm and a thickness of 4 mm under a pressure of 35 Mpa. The pressed metal cylinder tablet was placed in a quartz crucible and sintered in a vertical tube furnace, with a sintering temperature of 1000 ℃ and a sintering time of 10 h. Argon was introduced for protection during sintering to prevent oxidation. The cooling was performed by furnace cooling. After cooling, a rare earth modified corrosion resistant high-entropy alloy CuTiCrAlNiCe was obtained, which can be used as a target material to be sputtered onto the surface of a material to form a protective layer. The obtained rare earth modified corrosion resistant high-entropy alloy is shown in FIG. 1. Figure 1

[0036] Example 2

[0037] ​Aluminum powder, chromium powder, copper powder, titanium powder, nickel powder and yttrium-nickel intermetallic powder with average particle size of 75-100 μm were weighed according to the molar ratio of 1:1:1:1:1:1, yttrium-nickel intermetallic powder was weighed according to the molar ratio of 1:1, and the purity of the metal powder was more than 99.99%. The weighed metal powder was poured into a stainless steel plasma ball mill, and stainless steel ball milling beads were weighed according to the ball-to-powder ratio of 10:1. The ball milling beads were poured into the plasma ball mill, and argon was filled into the ball milling tank for protection. The beads with a diameter of 16 mm accounted for 20%, the beads with a diameter of 10 mm accounted for 25%, and the beads with a diameter of 5 mm accounted for 55%. The planetary ball mill was operated at 1300 rpm power 8 kW for 10 h of plasma mechanical mixing. The mixed alloy powder was weighed 4 g and poured into a mold, and a powder tablet press was used to press into a cylinder with a diameter of 15 mm and a thickness of 4 mm under a pressure of 35 Mpa. The pressed metal cylinder sheet was placed in a quartz crucible and sintered in a vertical tube furnace, with a sintering temperature of 1000 ℃ and a sintering time of 10 h. Argon was introduced during sintering to prevent oxidation. The cooling was carried out by furnace cooling. After cooling, the rare earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiY was obtained.

[0038] Figure 2 、 Figure 3 The SEM images of the rare earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiRe of Example 1 and the rare earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiY of Example 2, respectively. It can be clearly seen from Figure 2 and 3 that the alloy presents uniform and dense microstructure, without obvious loose, pore or composition segregation phenomenon, reducing the penetration channel of corrosion medium and avoiding the acceleration of corrosion at defects. Combined with the conversion film effect of rare earth elements, a synergistic protection mechanism is formed; the microstructure prevents the penetration of corrosion medium, and the conversion film inhibits the electrochemical corrosion of the alloy matrix, which together ensures the excellent corrosion resistance of the alloy.

[0039] Example 3

[0040] Aluminum powder, chromium powder, copper powder, titanium powder, nickel powder and lanthanum-nickel interalloy powder with an average particle size of 75-100 μm were weighed according to a molar ratio of 1:1:1:1:1:1, and the purity of the metal powder was above 99.99%. The weighed metal powder was poured into a stainless steel plasma ball mill, stainless steel ball milling beads were weighed according to a ball-to-powder ratio of 10:1, and the ball milling beads were poured into the plasma ball mill. The ball milling jar in the ball mill was filled with argon for protection. The 16 mm diameter beads accounted for 20%, the 10 mm diameter beads accounted for 25%, and the 5 mm diameter beads accounted for 55%. The plasma mechanical mixing was performed on the planetary ball mill at 1300 rpm and 8 kW for 10 h. The mixed alloy powder was weighed at 5 g and poured into a mold. A powder tablet press was used to press the alloy powder into a cylindrical body with a diameter of 15 mm and a thickness of 4 mm under a pressure of 35 Mpa. The pressed metal cylindrical body was placed in a quartz crucible and sintered in a vertical tube furnace. The sintering temperature was 1000 ℃, and the sintering time was 10 h. Argon was introduced during the sintering process to prevent oxidation. The cooling was performed by furnace cooling. After cooling, the rare earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiLa was obtained.

[0041] Example 4

[0042] Aluminum powder, chromium powder, copper powder, titanium powder, nickel powder and lanthanum-nickel interalloy powder with an average particle size of 75-100 μm were weighed according to a molar ratio of 1:1:1:1:1:1, and the purity of the metal powder was above 99.99%. The weighed metal powder was poured into a stainless steel plasma ball mill, stainless steel ball milling beads were weighed according to a ball-to-powder ratio of 10:1, and the ball milling beads were poured into the plasma ball mill. The ball milling jar in the ball mill was filled with argon for protection. The 16 mm diameter beads accounted for 20%, the 10 mm diameter beads accounted for 25%, and the 5 mm diameter beads accounted for 55%. The plasma mechanical mixing was performed on the planetary ball mill at 1300 rpm and 8 kW for 10 h. The mixed alloy powder was weighed at 5 g and poured into a mold. A powder tablet press was used to press the alloy powder into a cylindrical body with a diameter of 15 mm and a thickness of 4 mm under a pressure of 35 Mpa. The pressed metal cylindrical body was placed in a quartz crucible and sintered in a vertical tube furnace. The sintering temperature was 1000 ℃, and the sintering time was 10 h. Argon was introduced during the sintering process to prevent oxidation. The cooling was performed by furnace cooling. After cooling, the rare earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiLa was obtained.

[0043] Comparative Example 1

[0044] The same method as in Example 1 was used to prepare a high-entropy alloy, except that no rare earth raw material was added to the raw materials. Comparative Example 1 prepared a high-entropy alloy CuTiCrAlNi.

[0045] Figure 4XRD patterns of high-entropy alloys prepared for Examples 1-3 and Comparative Example 1, from Figure 4 As can be seen from the XRD, a clear characteristic diffraction peak of body-centered cubic (BCC) phase appears at 2θ=43°, indicating that the prepared alloy is a single solid solution structure, and the crystal structure type is clearly BCC phase; further observation of the XRD pattern shows that the alloy only presents a sharp single-phase solid solution characteristic peak, and no impurity phase diffraction peak is detected, indicating that when Y and La are used as rare earth (Re) elements, the "plasma ball milling + powder metallurgy" composite preparation process defined in the present application can effectively construct a thermodynamically stable single-phase solid solution structure.

[0046] Example 5

[0047] The rare earth modified corrosion resistant high-entropy alloy CuTiCrAlNiCe prepared by the same method as Example 1 is different from Example 1 in that the plasma ball milling time is 15h, 20h, or a planetary ball mill is used for 10h. Figure 5 Tafel polarization curves for different ball milling methods (e.g. plasma ball milling vs. planetary ball milling), different plasma ball milling times (5h, 15h, 20h); Figure 6 The Nyquist plot of the rare earth modified corrosion resistant high-entropy alloy CuTiCrAlNiCe of Example 1. The results show that the Nyquist plot of the alloy ball milled for 15h has a relatively large capacitive arc in the high frequency region, indicating that its charge transfer resistance is relatively high, and the corrosion reaction on the electrode surface is hindered. The impedance value corresponding to the curve in the low frequency region is the highest. This indicates that at low frequency, the corrosion medium diffuses to the alloy surface with the greatest difficulty, i.e. the alloy has the strongest resistance to corrosion medium. Comparing the Nyquist plot of the alloy ball milled for 10h, it is found that its impedance value in the low frequency region is significantly lower than that of the alloy ball milled for 15h, indicating that the alloy ball milled for 10h has relatively easy diffusion of corrosion medium and poor corrosion resistance; the impedance value of the alloy ball milled for 20h in the low frequency region is also lower than that of the alloy ball milled for 15h, indicating that the alloy ball milled for 20h has poor corrosion resistance. The impedance arc reflects the hindering effect of charge transfer on the electrode surface, the larger the radius of the capacitive arc, the greater the resistance of charge transfer, and the better the corrosion resistance of the material. The slope can also reflect the pros and cons of corrosion resistance. The smaller the slope, the smaller the reaction resistance, the greater the corrosion rate, and the more easily corroded. The larger the slope, the greater the reaction resistance, the smaller the corrosion rate, and the more corrosion resistant.

[0048] Example 6

[0049] The rare earth modified corrosion resistant high-entropy alloy CuTiCrAlNiCe prepared by the same method as Example 1 is different from Example 1 in that the sintering temperature is 800℃, 900℃.

[0050] Figure 7The image shows the DSC curves of the rare-earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiCe from Example 1. Figure 7 As can be seen, the curves show no obvious abnormal exothermic / endothermic peaks in the 800 to 1200℃ range, and no crystal phase transformation characteristics, proving that the alloy has excellent thermal stability. This characteristic ensures that the alloy will not undergo phase transformation due to temperature fluctuations in practical applications (such as marine environments, temperature range of -20℃ to 60℃), thus maintaining stable corrosion resistance.

[0051] Corrosion resistance test structure for rare earth modified corrosion-resistant high-entropy alloys, such as Figure 8 and Figure 9 As shown. (From...) Figure 8 and Figure 9 It can be seen that: the alloy sintered at 1000℃: after 15 days of full immersion / salt spray test, there are no obvious corrosion spots or rust products on the surface, and the corrosion rate is extremely low, ≤0.1mm / year, which is significantly better than traditional 304 stainless steel; the alloy sintered at 900℃: after 15 days of test, there is no obvious rust on the surface, but a small number of light-colored corrosion spots may appear, with a corrosion rate ≤0.2mm / year, which is slightly higher than that at 1000℃, but still meets the "excellent corrosion resistance" standard; the alloy sintered at 800℃: after 15 days of test, a small number of dark-colored corrosion spots may appear on the surface, but there is no serious rust, and the corrosion rate is less than 0.3mm / year.

[0052] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. Other modifications can be easily made by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A method for preparing a rare earth modified corrosion resistant high-entropy alloy, characterized in that, The method comprises the following steps: (1) weighing copper powder Cu, titanium powder Ti, chromium powder Cr, aluminum powder Al, nickel powder Ni and intermediate alloy powder according to a certain proportion, the intermediate alloy powder being one of CeNi, LaNi, YNi and PrNi; (2) adding the above raw materials into a plasma ball mill for high-energy mechanical mixing, wherein the ball-to-powder ratio is 10-15:1; (3) pressing the mixed powder into small round ingots; (4) sintering the small round ingots at 800-1000℃ for 8-10 h under argon protection, so that the elements are fully diffused to form a saturated single-phase solid solution, i.e. a rare earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiRE is prepared, wherein RE is any one of Ce, La, Y and Pr; In step (1), the raw materials are weighed according to a molar ratio of 1:1:1:1:1:1; the molar ratio of the two elements in the intermediate alloy powder is 1:

1.

2. The production method according to claim 1, characterized by, In step (2), the rotation speed of the plasma ball mill is 1000 rpm-1300 rpm, the power is 7-9 kW, and the mixing time is 10-15 h.

3. The preparation method according to claim 1, characterized in that, In step (2), the plasma ball mill uses stainless steel milling beads, wherein the beads with a diameter of 16 mm account for 10-25 wt.%, the beads with a diameter of 10 mm account for 10-25 wt.%, and the beads with a diameter of 3-7 mm account for 50-70 wt.%. The milling beads and metal powder are poured into the plasma ball mill, argon is filled for protection, and plasma mechanical mixing is carried out.

4. The method of claim 1, wherein, In step (3), the DY-20 tablet press is used to press the alloy cylinders.

5. The preparation method according to claim 1, characterized in that, In step (3), 3-5 g of powder is poured into the mold during pressing, and the alloy cylinders with a diameter of 10-20 mm and a thickness of 2-4 mm are pressed under a pressure of 20-40 MPa.

6. The method of claim 1, wherein, After the sintering step of step (4), the cooling is carried out by furnace cooling.

7. The rare earth modified corrosion-resistant high-entropy alloy prepared by the preparation method according to any one of claims 1-6, wherein the obtained high-entropy alloy is CuTiCrAlNiRE.

8. The use of the rare earth modified corrosion resistant high-entropy alloy according to claim 7, characterized in that The rare earth modified corrosion-resistant high-entropy alloy is used as target material to be sputtered onto the surface of a material to form a protective layer.

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