Permanent magnetic rare earth high-entropy alloy and preparation method thereof

Abstract

The invention discloses a permanent magnetic rare earth high-entropy alloy and a preparation method thereof, and belongs to the technical field of new materials. An RE-Fe-Co-X alloy strip is prepared through consumable vacuum arc or induction melting and single-roller melt-spinning, and then a single-phase or complex-phase structure composed of rare earth permanent magnetic phases is obtained through vacuum annealing treatment, so that the alloy has the obvious permanent magnetic characteristic. The coercive force of the RE-Fe-Co-X high-entropy alloy prepared by the method provided by the invention under a 1.8 T external magnetic field exceeds 134.6 kA / m. The permanent magnetic rare earth high-entropy alloy is obtained through electric arc melting, melt-spinning and proper heat treatment. The technical blank of preparing the permanent magnetic high-entropy alloy material is filled, and the development direction of the permanent magnetic material is expanded.

Description

Technical Field

[0001] This invention relates to the field of new materials technology, and in particular to a permanent magnetic rare earth high entropy alloy and its preparation method. Background Technology

[0002] High-entropy alloys are novel alloys composed of multiple elements in equiatomic or near-equiatomic ratios. They represent an emerging field in materials research with significant research value and broad application prospects. By designing the alloy components and composition, high-entropy alloys with varying combinations of properties, such as high hardness, work-hardening strength, resistivity, ferromagnetism, and corrosion resistance, can be obtained. In recent years, the unique ferromagnetic properties of high-entropy alloys have also attracted increasing attention; for example, FeCoNi(AlSi) alloys have been discovered. 0.2 High-entropy alloys possess excellent comprehensive properties, exhibiting high saturation magnetization and resistivity [W. Feng, et al., Metals, 7, (2017); J. Wang, et al., Entropy, 20, (2018).]. High-entropy alloys with excellent magnetocaloric capabilities can be prepared by introducing heavy rare earth elements [MCGao, et al., Springer, 2016]. Fe-Co-Ni-(C,Si,P,B) high-entropy amorphous alloys, combining the characteristics of high-entropy and amorphous alloys, possess excellent soft magnetic properties such as low coercivity, high effective permeability, and low iron loss [T. Qi, et al., Intermetallics, 66, (2015).]. Adding Co to Fe-Pt-B alloys yields soft magnetic nanocrystalline and amorphous alloys that conform to the compositional characteristics of high-entropy alloys [Ma Dianguo et al., Acta Metallurgica Sinica, 53, (2017)]. These studies only involve the soft magnetic properties of high-entropy alloys, while there are no reports on their permanent magnetic properties.

[0003] Rare-earth permanent magnet alloys are a major research direction in current permanent magnet materials. These alloys are composed of rare-earth elements (RE) and transition metals (TM), such as SmCo5 and Sm2Co. 17 Sm2Fe 17 N x and Nd2Fe 14Alloys such as B exhibit excellent permanent magnetic properties. Recently, nanocomplex permanent magnet materials, possessing both the high magnetization and high coercivity of soft magnetic materials and exhibiting extremely high theoretical energy products, have been proposed and have rapidly become a hot topic in the research and development of novel permanent magnet materials. Current research indicates that the microalloying of metalloid elements is beneficial for refining the alloy microstructure and improving the magnetic properties of the alloy [TRGao, et al., Appl. Phys. Lett., 102, (2013).]. This invention proposes a method for preparing rare-earth-based high-entropy permanent magnet alloys, combining the compositional characteristics of high-entropy alloys with the structural requirements of nanocomplex permanent magnet materials. This not only provides a new approach to the preparation of permanent magnet materials but also opens up a new research direction for high-entropy alloys. Summary of the Invention

[0004] The purpose of this invention is to provide a permanent magnetic rare earth high entropy alloy and its preparation method to solve the above-mentioned technical problems.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A permanent magnetic rare-earth high-entropy alloy, wherein the alloy is a single or multi-phase structure composed of rare-earth permanent magnetic phases, mainly composed of rare earth elements (RE = La, Ce, Pr, Nd, Sm, Gd, Dy, Er, etc.), Fe, Co, Y, Ti, V, Cr, Mn, Ni, Cu, Zn, Zr, Nb, Hf, Ta, WB, C, Al, Si, P, etc., and its chemical composition is RE a Fe b Co c X d In the formula, X = Y, Ti, V, Cr, Mn, Ni, Cu, Zn, Zr, Nb, Hf, Ta, WB, C, Al, Si or P; a, b, c and d represent the atomic percentages of the corresponding elements, satisfying 10≤a≤50, 10≤b≤55, 0≤c≤55, 0≤d≤40, and a+b+c+d=100.

[0007] High-entropy alloys possess permanent magnet properties, with a coercivity of 134.6-885.7 kA / m when an external magnetic field of 1.8 T is applied.

[0008] A method for preparing a permanent magnetic rare-earth high-entropy alloy includes the following steps:

[0009] (1) RE-Fe-Co-X (X = Y, Ti, V, Cr, Mn, Ni, Cu, Zn, Zr, Nb, Hf, Ta, WB, C, Al, Si or P) master alloy ingots were prepared by arc melting or high-frequency induction melting under Ar atmosphere;

[0010] (2) Amorphous or amorphous / nanocrystalline alloy strips are prepared by single-roller spinning technology, and the strip thickness and phase structure are controlled by the rotation speed of the copper roller;

[0011] (3) Obtain a sample containing uniformly distributed SmCo3, SmCo5, SmCo7, and SmFe by directly or by vacuum annealing the strip sample. 12 Sm2Co 17 Sm3Fe 29 or Nd2Fe 14 Permanent magnetic rare earth high-entropy RE-Fe-Co-X alloy with rare earth permanent magnetic phases such as B.

[0012] A method for preparing a permanent magnetic rare-earth high-entropy alloy includes the following steps:

[0013] (1) Use high-purity raw materials or Fe-P binary alloys with a purity greater than 99.5wt% for La, Ce, Pr, Nd, Sm, Gd, Dy, Er, Y, Fe, Co, Ni, Ti, V, Cr, Mn, Cu, Zn, Zr, Nb, Hf, Ta, W, B, C, Al, and Si, or according to RE a Fe b Co c X d (Atomic percentage, 10≤a≤50, 10≤b≤55, 0≤c≤55, 0≤d≤40, and a+b+c+d=100) The nominal components are weighed and batched.

[0014] (2) Alloys containing P or C elements are prepared into master alloy ingots by high-frequency induction melting in an Ar atmosphere. Other alloys are prepared into master alloy ingots by non-consumable electric arc furnace in an Ar atmosphere. The alloys are repeatedly melted four times to ensure uniform composition. The master alloy ingots are made into continuous alloy strip samples with a width of about 2 mm and a thickness of about 10 to 50 μm by single-roller strip spinning equipment in an Ar atmosphere. The strip thickness is controlled by the rotation speed of the copper roller.

[0015] (3) Detect the structure and thermal properties of the alloy strip samples prepared at different copper roller speeds; combine the structure and thermal properties analysis to determine the heat treatment temperature of the alloy strip; if the alloy strip contains a permanent magnetic phase, step (5) can be implemented directly; otherwise, step (4) is implemented.

[0016] (4) The alloy strips are annealed by vacuum heat treatment to obtain an alloy containing rare earth permanent magnet phase;

[0017] (5) The obtained alloy strips were characterized by their structure and tested for their magnetic properties;

[0018] The structure of the samples before and after heat treatment was characterized by X-ray diffraction and high-resolution transmission electron microscopy; the alloy composition distribution was determined by energy dispersive spectroscopy; the thermal properties of the strip samples were detected by differential scanning calorimetry; and the magnetic properties of the alloy samples before and after heat treatment were tested using a vibrating sample magnetometer.

[0019] Compared with existing technologies, this invention has the following advantages: This invention obtains a permanent magnetic rare-earth high-entropy alloy through arc melting, strip spinning, and appropriate heat treatment. This invention fills the technological gap in the preparation of permanent magnetic high-entropy alloy materials and expands the development direction of permanent magnet materials. Attached Figure Description

[0020] Figure 1 The Sm of this invention is annealed at 863K for 600s. 30 Fe 35 Co 35 X-ray diffraction pattern of alloy strips.

[0021] Figure 2 The Sm of this invention is annealed at 863K for 600s. 30 Fe 35 Co 35 Transmission electron microscope image of the alloy strip.

[0022] Figure 3 The Sm of this invention is annealed at 863K for 600s. 30 Fe 35 Co 35 Hysteresis loop diagram of alloy strip. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0024] Example 1

[0025] Now, let's take the component as Sm 30 Fe 35 Co 35 Taking rare earth-based high-entropy permanent magnet alloys as an example, the implementation methods for their preparation and performance testing are described in detail with reference to the accompanying drawings.

[0026] Step 1: Prepare the ingredients;

[0027] High-purity Fe (99.9 wt.%), Co (99.9 wt.%) and Sm (99.5 wt.%) raw materials were selected and processed according to Sm... 30 Fe 35 Co 35 The ingredients are weighed and dispensed.

[0028] Step 2: Alloy ingot smelting;

[0029] The weighed metal raw material is placed into the water-cooled copper crucible of the electric arc melting furnace, and a vacuum of 3×10⁻⁶ is drawn. -3 Pa was then introduced, followed by the filling of an appropriate amount of argon gas, and the alloy was smelted. After smelting, the alloy ingot was flipped over and smelted repeatedly four times to obtain Sm with uniform composition. 30 Fe 35 Co 35 Alloy ingot.

[0030] Step 3: Preparation of rapidly cooled strip samples;

[0031] After the alloy ingot is crushed, it is placed into a quartz tube with a nozzle diameter of approximately 0.5 mm, and then placed inside an induction heating coil. Using liquid quenching technology under argon protection, the alloy sample is melted and sprayed onto a high-speed rotating copper roller to prepare Sm. 30 Fe 35 Co 35 Alloy strip sample. The strip spinning speed is about 40 m / s, the width of the alloy strip is about 1-2 mm, and the thickness is about 20 μm.

[0032] Step 4: Microstructure analysis of the alloy strip;

[0033] The structure of the quenched strip alloy was analyzed by X-ray diffraction (XRD) (Cu-Kα radiation, λ = 0.15406 nm).

[0034] Step 5: Vacuum annealing;

[0035] The alloy strip was placed into a quartz tube with an inner diameter of 6 mm and a wall thickness of 1 mm, and the vacuum was reduced to 2 × 10⁻⁶. -3 The sample was sealed below Pa, and then placed in an annealing furnace for isothermal annealing at 863K for 600s, and then removed and water-quenched.

[0036] Step Six: Measurement of the microstructure and magnetic properties of the annealed sample;

[0037] The structure of the annealed sample was analyzed by XRD. Figure 1 The XRD pattern shows that the annealed sample consists of a permanent magnetic Sm(Fe,Co)7 phase and a soft magnetic Sm(Fe,Co)2 phase. Figure 2 This indicates that the high-entropy alloy has a uniform microstructure after heat treatment, with an average grain size of about 50 nm. Figure 3 This is the hysteresis loop of the high-entropy alloy under an external magnetic field of 1.8T, indicating that the alloy possesses excellent permanent magnet properties; when the annealing temperature is 863K, the alloy's coercivity ( i H c The value is 357.3 kA / m.

[0038] Example 2

[0039] The component is Sm12.5 Fe 40 Co 40 (V 0.7 W 0.3 ) 7.5 High-entropy alloys;

[0040] The specific implementation steps are the same as in Example 1, and the final alloy obtained is... i H c It is 462.4 kA / m.

[0041] Example 3

[0042] The component is (Sm 0.5 Pr 0.5 ) 30 Fe 30 Co 30 B 10 High-entropy alloys;

[0043] The specific implementation steps are the same as in Example 1, and the final alloy obtained is... i H c It is 248.7 kA / m.

[0044] Example 4

[0045] The component is (Sm 0.5 Pr 0.5 ) 20 Fe 30 Co 30 (Ni 0.5 Al 0.5 ) 20 High-entropy alloys;

[0046] The specific implementation steps are the same as in Example 1, and the final alloy obtained is... i H c It is 322.5 kA / m.

[0047] Example 5

[0048] The component is Sm 12.5 Fe 25 Co 55 (Mn 0.25 Cu 0.25 Zr 0.5 ) 7.5 High-entropy alloys;

[0049] The specific implementation steps are the same as in Example 1, and the final alloy obtained is... i H c It is 764.3 kA / m.

[0050] Example 6

[0051] The component is (Sm0.8 La 0.05 Ce 0.15 ) 11 Fe 20 Co 55 (Ti 0.1 Cu 0.1 B 0.8 ) 14 High-entropy alloy; the specific implementation steps are the same as in Example 1, and the final alloy obtained is... i H c It is 506.9 kA / m.

[0052] Example 7

[0053] The component is Pr 12 Fe 27 Co 27( Ni 0.8 B 0.2 ) 34 High-entropy alloys;

[0054] The specific implementation steps are the same as in Example 1, and the final alloy obtained is... i H c It is 236.2 kA / m.

[0055] Example 8

[0056] The component is (Pr 0.8 Nb 0.15 Er 0.05 ) 10 Fe 54 Co 30 B6 high-entropy alloy;

[0057] The specific implementation steps are the same as in Example 1, and the final alloy obtained is... i H c It is 494.8 kA / m.

[0058] Example 9

[0059] The component is (Pr 0.9 Dy 0.1 )8Fe 45 Co 40 (B 0.9 W 0.05 T 0.05 The specific implementation steps for the high-entropy alloy of 7 are the same as in Example 1, and the final alloy obtained is... i H c It is 388.4 kA / m.

[0060] Example 10

[0061] The component is Nd 30 Fe 35Co 35 High-entropy alloys;

[0062] The specific implementation steps are the same as in Example 1, and the final alloy obtained is... i H c It is 134.6 kA / m.

[0063] Example 11

[0064] The component is Nd 10 Fe 50 Co 34 B6 high-entropy alloy;

[0065] The specific implementation steps are the same as in Example 1, and the final alloy obtained is... i H c It is 885.7 kA / m.

[0066] Example 12

[0067] The component is Nd 20 Fe 35 Co 35 Al 10 High-entropy alloys;

[0068] The specific implementation steps are the same as in Example 1, and the final alloy obtained is... i H c It is 363.1 kA / m.

[0069] Example 13

[0070] The component is Nd 12 Fe 50 Co 26 (B 0.9 Si 0.1 ) 12 High-entropy alloys;

[0071] The specific implementation steps are the same as in Example 1, and the final alloy obtained is... i H c It is 579.3 kA / m.

[0072] Example 14

[0073] The component is (Nd 0.5 Pr 0.3 Gd 0.1 Dy 0.1 ) 12 Fe 70 Co6(Ti 0.1 B 0.9 ) 12 High-entropy alloys;

[0074] The specific implementation steps are the same as in Example 1, and the final alloy obtained is...i H c It is 640.3 kA / m.

[0075] Example 15

[0076] The component is (Nd 0.8 Dy 0.17 Y 0.03 )8Fe 52 Co 20 (B 0.8 C 0.1 P 0.1 ) 20 High-entropy alloys;

[0077] P element addition was achieved by proportioning and weighing an Fe-P master alloy, and the master alloy ingot was prepared by high-frequency induction melting in an Ar atmosphere. Other implementation steps were the same as in Example 1. The final alloy obtained was... i H c It is 226.4 kA / m.

[0078] The above description represents a preferred embodiment of the present invention. For those skilled in the art, any changes, modifications, substitutions, and variations made to the implementation methods without departing from the principles and spirit of the present invention, based on the teachings of the present invention, still fall within the protection scope of the present invention.

Claims

1. A permanent magnetic rare-earth high-entropy alloy, characterized in that, The alloy has a single or multiphase structure composed of rare-earth permanent magnetic phases, and its chemical composition is RE. a Fe b Co c X d In the formula, X = Y, Ti, V, Cr, Mn, Ni, Cu, Zn, Zr, Nb, Hf, Ta, WB, C, Al, Si or P; a, b, c and d represent the atomic percentages of the corresponding elements, satisfying 10≤a≤50, 10≤b≤55, 0≤c≤55, 0≤d≤40, and a+b+c+d=100.

2. The permanent magnetic rare-earth high-entropy alloy according to claim 1, characterized in that, High-entropy alloys possess permanent magnet properties, with a coercivity of 134.6-885.7 kA / m when an external magnetic field of 1.8 T is applied.

3. The method for preparing a permanent magnetic rare-earth high-entropy alloy according to claim 1 or 2, characterized in that, Includes the following steps: (1) RE-Fe-Co-X (X = Y, Ti, V, Cr, Mn, Ni, Cu, Zn, Zr, Nb, Hf, Ta, WB, C, Al, Si or P) master alloy ingots were prepared by arc melting or high-frequency induction melting under Ar atmosphere; (2) Amorphous or amorphous / nanocrystalline alloy strips are prepared by single-roller spinning technology, and the strip thickness and phase structure are controlled by the rotation speed of the copper roller; (3) Obtain a sample containing uniformly distributed SmCo3, SmCo5, SmCo7, and SmFe by directly or by vacuum annealing the strip sample. 12 Sm2Co 17 Sm3Fe 29 or Nd2Fe 14 Permanent magnetic rare earth high-entropy RE-Fe-Co-X alloy with rare earth permanent magnetic phases such as B.

4. The method for preparing a permanent magnetic rare-earth high-entropy alloy according to claim 1 or 2, characterized in that, Includes the following steps: (1) Use high-purity raw materials or Fe-P binary alloys with a purity greater than 99.5wt% for La, Ce, Pr, Nd, Sm, Gd, Dy, Er, Y, Fe, Co, Ni, Ti, V, Cr, Mn, Cu, Zn, Zr, Nb, Hf, Ta, W, B, C, Al, and Si, or according to RE a Fe b Co c X d (Atomic percentage, 10≤a≤50, 10≤b≤55, 0≤c≤55, 0≤d≤40, and a+b+c+d=100) The nominal components are weighed and batched. (2) Alloys containing P or C elements are prepared into master alloy ingots by high-frequency induction melting in an Ar atmosphere. Other alloys are prepared into master alloy ingots by non-consumable electric arc furnace in an Ar atmosphere. The alloys are repeatedly melted four times to ensure uniform composition. The master alloy ingots are made into continuous alloy strip samples with a width of about 2 mm and a thickness of about 10 to 50 μm by single-roller strip spinning equipment in an Ar atmosphere. The strip thickness is controlled by the rotation speed of the copper roller. (3) Detect the structure and thermal properties of the alloy strip samples prepared at different copper roller speeds; combine the structure and thermal properties analysis to determine the heat treatment temperature of the alloy strip; if the alloy strip contains a permanent magnetic phase, step (5) can be implemented directly; otherwise, step (4) is implemented. (4) The alloy strips are annealed by vacuum heat treatment to obtain an alloy containing rare earth permanent magnet phase; (5) The obtained alloy strips were characterized by their structure and tested for their magnetic properties; The structure of the samples before and after heat treatment was characterized by X-ray diffraction and high-resolution transmission electron microscopy; the alloy composition distribution was determined by energy dispersive spectroscopy; the thermal properties of the strip samples were detected by differential scanning calorimetry; and the magnetic properties of the alloy samples before and after heat treatment were tested using a vibrating sample magnetometer.

Images