Hydrogenated heavy rare earth-based amorphous alloy powder material and method of making same

Abstract

This invention discloses a hydrogenated heavy rare earth-based amorphous alloy powder material, and also discloses a method for preparing the aforementioned hydrogenated heavy rare earth-based amorphous alloy powder material. This invention achieves amorphous forming capability by selecting specific components and synergistically adjusting their content. The invention utilizes a gas atomization method to obtain amorphous alloy powders with uniform size and good sphericity, effectively suppressing the crystallization degree of the alloy material and significantly improving the hydrogen absorption degree and rate of the amorphous alloy powder during hydrogenation. Furthermore, by subjecting the amorphous alloy powder to isothermal hydrogen absorption treatment, this invention significantly increases the magnetic entropy change of the alloy, achieving a maximum magnetic entropy change of 18.7 J kg under a 5T external field. ‑1 K ‑1 The hydrogenated heavy rare earth-based amorphous alloy powder material of this invention can be used as a refrigerant in the field of low-temperature magnetic refrigeration and has good thermal conversion efficiency.

Description

Technical Field

[0001] This invention relates to a hydrogenated heavy rare earth-based amorphous alloy powder material, and also to a method for preparing the above-mentioned amorphous alloy powder material. Background Technology

[0002] Refrigeration technology has a wide range of applications, from high-tech to everyday life. In recent years, magnetic refrigeration technology, as a novel refrigeration technology, has received widespread attention from scientists. Compared with traditional gas compression refrigeration technology, magnetic refrigeration technology, with its superior characteristics such as being environmentally friendly, highly efficient and energy-saving, and exhibiting low vibration, is considered to have broad application prospects in a range of refrigeration fields, including industrial production, biomedicine, and aerospace.

[0003] Magnetic refrigeration technology is based on the magnetocaloric effect of materials, specifically the thermal phenomenon caused by changes in the alignment of magnetic moments when an external magnetic field changes. Over decades of development, scientists have discovered a series of alloy systems with excellent magnetocaloric effects, such as Gd5(Si2Ge2), LaFeSi, and NiMnGa alloys, all of which exhibit giant magnetocaloric effects. However, these alloy systems are all first-order magnetic phase transition materials, and their narrow cooling temperature range, large magnetic hysteresis, and thermal hysteresis limit their application areas.

[0004] Compared to crystalline materials, amorphous magnetic refrigeration materials exhibit second-order magnetic phase transition characteristics. Due to their disordered atomic structure, they possess a wider magnetic transition temperature range, smaller magnetic hysteresis and thermal hysteresis, resulting in higher refrigeration efficiency. Furthermore, amorphous magnetic refrigeration materials also possess advantages such as high resistivity, adjustable magnetic transition temperature, and wear and corrosion resistance, better meeting the diverse needs of practical production and daily life. In recent years, scientists have explored the preparation of RETMAl (RE represents rare earth elements, TM represents transition metal elements) alloy systems, such as GdCoAl, GdNiAl, and DyCoAlSi; however, most of these alloys exhibit limited magnetic entropy changes.

[0005] Chinese patent CN106929775A discloses a gadolinium-based bulk amorphous alloy material with high amorphous forming ability and high magnetocaloric effect, with the chemical formula Gd. a Co b Al c Si d Fe e Where a, b, c, d, and e represent the atomic percentages of the corresponding elements, and most alloys in this system have a maximum magnetic entropy change of less than 10 J kg under a 5T external field. -1 K -1 The value is relatively low.

[0006] Chinese patent CN102691020B discloses a gadolinium-based bulk amorphous alloy with both large amorphous forming capability and high magnetocaloric effect, and its preparation method. The molecular formula is Gd. a Ni b Al c M d Where a, b, c, and d represent the atomic percentages of the corresponding elements, and M is one or more of B, Si, C, and P. The maximum magnetic entropy change of this alloy under a 5T external field can only reach 9.25 J / kg. -1 K -1 This limits the application of the alloy.

[0007] Chinese patent CN112342475A discloses a microalloyed heavy rare earth-based amorphous alloy, its preparation method, and its application, with the molecular formula R. 55 Co 20 Al 25-x M x In this system, R represents a heavy rare earth element selected from Gd, Tb, Dy, Ho, Er, and Tm; and M represents a metalloid element selected from B, C, N, and Si. However, most alloys in this system exhibit a maximum magnetic entropy change of less than 10 J kg under a 5T external field. -1 K -1 The value is relatively low. Summary of the Invention

[0008] Purpose of the invention: The purpose of this invention is to provide a hydrogenated heavy rare earth-based amorphous alloy powder material, which can significantly improve the magnetic entropy change value of amorphous alloys, thereby effectively solving the problem of low magnetic entropy change value in existing heavy rare earth-based amorphous alloy systems. Another purpose of this invention is to provide a method for preparing the above-mentioned hydrogenated heavy rare earth-based amorphous alloy powder material.

[0009] Technical solution: The hydrogenated heavy rare earth-based amorphous alloy powder material of the present invention has the following molecular formula based on the percentage content of each element: (R a T b Al e ) 100-x H x ;

[0010] Where R represents a heavy rare earth element, either Gd or Dy; T represents a transition metal element, either Co or Ni.

[0011] Wherein, when R is Gd, 0≤a≤0.6; when R is Dy, 0≤a≤0.6; when T is Co, 0≤b≤0.2; when T is Ni, 0≤b≤0.2; 0.2≤e≤0.3; a+b+e=1; 50≤x≤70;

[0012] Or the molecular formula is: (R)a T b Al e M f ) 100-x H x ;

[0013] Wherein, R represents heavy rare earth elements, namely Gd or Dy; T represents transition metal elements, namely Co or Ni; and M represents metalloid elements, namely Si.

[0014] Where, 0≤a≤0.6, 0≤b≤0.2, 0.2≤e≤0.3, 0≤f≤0.01, a+b+e+f=1, 50≤x≤70.

[0015] The preparation method of the above-mentioned hydrogenated heavy rare earth-based amorphous alloy powder material includes the following steps:

[0016] (1) Weigh the corresponding raw materials according to the molecular formula of the heavy rare earth-based alloy (i.e., according to the mass ratio of each element); mix the raw materials and put them into an electric arc melting furnace, carry out electric arc melting under the protection of argon atmosphere, and obtain the master alloy ingot after cooling.

[0017] (2) Gas atomization powder preparation: The master alloy ingot is placed in the high-frequency melting furnace of the ultra-small metal powder preparation device to melt the alloy. When the alloy liquid flows into the atomization chamber for gas atomization dispersion, after cooling, high sphericity and low oxygen content amorphous alloy powder is obtained. The obtained powder is graded and sieved to obtain amorphous alloy powder with a particle size of 25-30 μm.

[0018] (3) Isothermal hydrogenation: The amorphous alloy powder obtained in step (2) is subjected to isothermal hydrogen absorption treatment to obtain hydrogenated heavy rare earth-based amorphous alloy powder material.

[0019] In step (1), the purity of Gd and Dy in the raw materials is not less than 99.9 wt%.

[0020] In step (1), the smelting process is as follows: the raw material is placed on a copper mold inside the electric arc melting furnace, the cavity is closed, and the cavity is evacuated to a vacuum of 5×10⁻⁶. -3 Below Pa, then high-purity argon gas is introduced until the pressure reaches 5 × 10⁻⁶. 4 Pa; First, the titanium ingot is melted to further remove the residual oxygen in the cavity, and then the remaining raw materials are melted; after the raw materials are melted, the melting continues for 2-3 minutes and heating is stopped. After the alloy is cooled to solidification with the crucible, it is turned over and melted repeatedly 5 times to obtain a master alloy ingot with uniform composition and small burn loss.

[0021] Vacuuming the smelting chamber is a necessary condition for preparing metal alloy ingots; the higher the vacuum level, the better, because a higher vacuum level results in a lower residual oxygen content within the chamber. High-purity argon gas is then introduced until the pressure reaches 5 × 10⁻⁶. 4Pa, because a protective atmosphere is needed after vacuuming; after the raw material melts, continue to melt for 2-3 minutes to make the raw material melt completely and mix more evenly; after melting once, turn the material over, and melt a total of five times. After turning the material over and melting five times, the element distribution of the alloy ingot is relatively uniform.

[0022] In step (2), the gas atomization powder preparation process is as follows: the surface oxide layer of the master alloy ingot is removed and cleaned, the alloy ingot is loaded into a quartz tube with an open top and placed into the high-frequency melting furnace of the ultra-small metal powder preparation device, and the alloy ingot is melted by induction melting under the protection of argon atmosphere. The alloy melt is sprayed through the graphite nozzle at the bottom of the quartz tube and atomized into fine droplets when it meets the high-speed argon gas flow. The droplets are rapidly solidified into amorphous alloy powder in the closed atomization tube.

[0023] In the gas atomization method, the entire cavity is evacuated to a high vacuum of 5×10⁻⁶ during the preparation process. -3 The pressure is then equalized by filling the cavity with high-purity argon gas until the pressure inside and outside is equal. This ensures that the alloy ingot is virtually free from oxygen during its transformation from solid to molten alloy and then to atomization into powder, resulting in a low oxygen content. Compared to ball milling, ball milling cannot achieve a vacuum degree of 5 × 10⁻⁶. -3 Pa. In addition, the powder preparation time of gas atomization is basically 30 minutes, but ball milling generally requires more than 6 hours. The longer time and lower vacuum will result in a high oxygen content in the powder produced by ball milling. Oxygen will react with all the metal elements in the alloy system to form metal oxides, which will affect the magnetocaloric properties of the alloy material.

[0024] The conditions for gas atomization powder production are as follows: first, evacuate the cavity to a vacuum of 5×10⁻⁶. -3 The pressure is below 8 MPa, and then argon gas is introduced for atomization.

[0025] The pressure of the argon gas flow during atomization affects the particle size of the resulting powder. The principle of gas atomization is that the molten alloy is sprayed into the atomization chamber, where it encounters the high-speed argon gas flow, breaking down into fine droplets that rapidly solidify into small powder particles. Insufficient atomization pressure leads to incomplete breakage, resulting in generally larger powder particles; conversely, excessive atomization pressure also results in generally larger powder particles. Atomization pressure of 8 MPa produces a higher proportion of small-diameter powder. The degree of crystallinity is primarily influenced by powder size. A high cooling rate is required for the alloy melt to form amorphous particles. Smaller powders experience higher cooling rates and thus higher amorphousness; larger powders have relatively lower cooling rates and are therefore more likely to crystallize.

[0026] In step (2), the grading and sieving process is as follows: the base plate, the 600-mesh screen, and the 500-mesh screen are placed sequentially from bottom to top. The alloy powder obtained in step (2) is placed on the 500-mesh screen, the top cover is placed on it, and the powder is sieved on a powder sieving machine for 20 minutes to obtain alloy powder with a particle size of 25-30 μm.

[0027] In step (3), the isothermal hydrogen absorption process is as follows: the heavy rare earth-based amorphous alloy powder obtained in step (2) is placed in a Sieverts-type gas-solid reaction test device, and the hydrogen pressure in the chamber is set to 5 MPa. A higher hydrogen pressure can accelerate the hydrogen absorption rate. The isothermal temperature is 200°C, which is below the glass transition temperature of the heavy rare earth-based alloy powder. After long-term isothermal treatment at this temperature, the amorphous alloy has a very low degree of crystallization, thus maintaining excellent magnetocaloric properties. The isothermal time is not less than 26 hours. The isothermal hydrogen absorption treatment can induce the precipitation of rare earth hydrides in the amorphous matrix, thereby significantly increasing the magnetic entropy change value of the alloy.

[0028] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The present invention enables the alloy material to have amorphous forming ability by selecting specific components and coordinating the content of each component; (2) The present invention can obtain amorphous alloy powder with uniform size and good sphericity by gas atomization, which can effectively suppress the degree of crystallization of the alloy material on the one hand, and effectively improve the degree and rate of hydrogen absorption of the amorphous alloy powder during hydrogenation on the other hand; (3) The present invention significantly improves the magnetic entropy change value of the alloy by isothermal hydrogen absorption treatment of the amorphous alloy powder, and the maximum magnetic entropy change value can reach 18.7 J kg under a 5T external field. -1 K -1 The hydrogenated heavy rare earth-based amorphous alloy powder material of this invention can be used as a refrigerant in the field of low-temperature magnetic refrigeration and has good thermal conversion efficiency. Attached Figure Description

[0029] Figure 1 (Gd) prepared for Example 1 and Comparative Example 1 0.55 Co 0.175 Al 0.275 ) 38.9 H 61.1 and Gd 55 Co 17.5 Al 27.5 XRD pattern of the powder;

[0030] Figure 2 To prepare 25–30 μm Gd by gas atomization 55 Co 17.5 Al 27.5 SEM images of amorphous alloy powder;

[0031] Figure 3 (Gd) prepared in Example 1 0.55 Co 0.175 Al 0.275 ) 38.9 H 61.1Magnetization curves of powder samples under field-cooled (FC) and zero-field-cooled (ZFC) conditions, with an external field of 0.01T;

[0032] Figure 4 (Gd) prepared in Example 1 0.55 Co 0.175 Al 0.275 ) 38.9 H 61.1 Isothermal magnetization curve of powder sample;

[0033] Figure 5 (Gd) prepared in Example 1 0.55 Co 0.175 Al 0.275 ) 38.9 H 61.1 Magnetic entropy change curve of powder sample;

[0034] Figure 6 Gd prepared for Comparative Example 1 55 Co 17.5 Al 27.5 Magnetization curves of powder samples under field-cooled (FC) and zero-field-cooled (ZFC) conditions, with an external field of 0.01T;

[0035] Figure 7 Gd prepared for Comparative Example 1 55 Co 17.5 Al 27.5 Isothermal magnetization curve of powder sample;

[0036] Figure 8 Gd prepared for Comparative Example 1 55 Co 17.5 Al 27.5 Magnetic entropy change curve of powder sample;

[0037] Figure 9 (Gd) prepared for Example 2 and Comparative Example 2 0.55 Ni 0.175 Al 0.275 ) 41.1 H 58.9 and Gd 55 Ni 17.5 Al 27.5 XRD pattern of the powder;

[0038] Figure 10 (Gd) prepared in Example 2 0.55 Ni 0.175 Al 0.275 ) 41.1 H 58.9 Magnetic entropy change curve of powder sample;

[0039] Figure 11 Gd prepared for Comparative Example 255 Ni 17.5 Al 27.5 Magnetic entropy change curve of powder sample;

[0040] Figure 12 Prepared for Example 3 and Comparative Example 3 (Dy 0.55 Co 0.2 Al 0.24 Si 0.01 ) 39.5 H 60.5 and Dy 55 Co 20 Al 24 XRD pattern of Si1 powder;

[0041] Figure 13 (Dy) prepared in Example 3 0.55 Co 0.2 Al 0.24 Si 0.01 ) 39.5 H 60.5 Magnetic entropy change curve of powder sample;

[0042] Figure 14 Dy prepared for Comparative Example 3 55 Co 20 Al 24 Magnetic entropy change curve of Si1 powder sample. Detailed Implementation

[0043] Example 1

[0044] The chemical formula is (Gd 0.55 Co 0.175 Al 0.275 ) 38.9 H 61.1 The preparation method of heavy rare earth-based amorphous alloy powder materials includes the following steps:

[0045] (1) Gd, Co, and Al raw materials with a purity greater than 99.9 wt.% were processed according to the molecular formula Gd 55 Co 17.5 Al 27.5 The atomic percentage of ingredients is shown.

[0046] (2) Place the raw material weighed in step (1) onto the copper mold inside the electric arc melting furnace, close the cavity, and evacuate the cavity to a vacuum of 5×10⁻⁶. -3 Below Pa, then high-purity argon gas is introduced until the pressure reaches 5 × 10⁻⁶. 4Pa; First, melt the titanium ingot for 2-3 minutes to further consume the residual oxygen in the cavity. Then, melt the alloy ingot twice with a small current (120-150A), and then melt the alloy ingot three times with a large current (200-250A). Before each melting, the alloy ingot is turned over by the robot arm equipped with the electric arc melting furnace. After the last melting is completed, it is naturally cooled for 20 minutes to obtain a master alloy ingot with uniform composition and small burn loss.

[0047] (3) Remove surface impurities from the master alloy ingot obtained in step (2) and clean it in alcohol using an ultrasonic cleaner for 3 minutes. Crush the cleaned alloy ingot into small pieces, load the alloy ingots into a quartz tube with a bottom aperture of 0.7 mm, and place it into the melting furnace of the ultra-small metal powder preparation device. Close the furnace door and evacuate the cavity to a vacuum of 5 × 10⁻⁶. -3 Below Pa, high-purity argon gas is then introduced until the pressure inside and outside the furnace door is equal. The pressure of the atomizing argon gas flow is set to 8 MPa, and the cooling water temperature is set to 10°C. Under the protection of the argon atmosphere, the induction heating power supply is turned on and the current is gradually increased until the alloy ingot melts. The molten alloy is sucked into the atomizing cylinder below the melting furnace through the graphite nozzle at the bottom of the quartz tube using the pressure difference. In the atomizing cylinder, the molten alloy meets the high-speed argon gas flow and is atomized into fine droplets, which are then quickly solidified into alloy powder. Under the action of the high-speed argon gas flow, the powder falls into the receiving hopper to obtain heavy rare earth-based amorphous alloy powder.

[0048] (4) Take out the alloy powder obtained in step (3) and sieve it with 500 and 600 mesh metal sieves to obtain Gd with a particle size of 25-30 μm. 55 Co 17.5 Al 27.5 powder;

[0049] (5) Place the amorphous alloy powder sample obtained in step (4) into a Sieverts-type gas-solid reaction test apparatus, raise the temperature of the sample chamber to 200℃ and hold for 30 min, fill the sample chamber with hydrogen to a pressure of 5 MPa, and perform isothermal treatment for 26 h. The mass fraction of hydrogen absorbed by the amorphous alloy powder is 1.51%. After conversion to atomic percentage, the molecular formula of the resulting hydrogenated heavy rare earth-based amorphous alloy powder is (Gd 0.55 Co 0.175 Al 0.275 ) 38.9 H 61.1 .

[0050] Comparative Example 1

[0051] The chemical formula is Gd 55 Co 17.5 Al 27.5 The preparation method of heavy rare earth-based amorphous alloy powder materials includes the following steps:

[0052] (1) Gd, Co, and Al raw materials with a purity greater than 99.9 wt.% were processed according to the molecular formula Gd 55 Co 17.5 Al 27.5 The atomic percentage of ingredients is shown.

[0053] (2) Place the raw material weighed in step (1) onto the copper mold inside the electric arc melting furnace, close the cavity, and evacuate the cavity to a vacuum of 5×10⁻⁶. -3 Below Pa, then high-purity argon gas is introduced until the pressure reaches 5 × 10⁻⁶. 4 Pa; First, melt the titanium ingot for 2-3 minutes to further consume the residual oxygen in the cavity. Then, melt the alloy ingot twice with a small current (120-150A), and then melt the alloy ingot three times with a large current (200-250A). Before each melting, the alloy ingot is turned over by the robot arm equipped with the electric arc melting furnace. After the last melting is completed, it is naturally cooled for 20 minutes to obtain a master alloy ingot with uniform composition and small burn loss.

[0054] (3) Remove surface impurities from the master alloy ingot obtained in step (2) and clean it in alcohol using an ultrasonic cleaner for 3 minutes. Crush the cleaned alloy ingot into small pieces, load the alloy ingots into a quartz tube with a bottom aperture of 0.7 mm, and place it into the melting furnace of the ultra-small metal powder preparation device. Close the furnace door and evacuate the cavity to a vacuum of 5 × 10⁻⁶. -3 Below Pa, high-purity argon gas is then introduced until the pressure inside and outside the furnace door is equal. The pressure of the atomizing argon gas flow is set to 8 MPa, and the cooling water temperature is set to 10°C. Under the protection of the argon atmosphere, the induction heating power supply is turned on and the current is gradually increased until the alloy ingot melts. The molten alloy is sucked into the atomizing cylinder below the melting furnace through the graphite nozzle at the bottom of the quartz tube using the pressure difference. In the atomizing cylinder, the molten alloy meets the high-speed argon gas flow and is atomized into fine droplets, which are then quickly solidified into alloy powder. Under the action of the high-speed argon gas flow, the powder falls into the receiving hopper to obtain heavy rare earth-based amorphous alloy powder.

[0055] (4) Take out the alloy powder obtained in step (3) and sieve it with 500 and 600 mesh metal sieves to obtain Gd with a particle size of 25-30 μm. 55 Co 17.5 Al 27.5 powder.

[0056] The XRD patterns of the amorphous alloy powders prepared in Example 1 and Comparative Example 1 are as follows: Figure 1 As shown, the XRD pattern does not contain any sharp crystallization peaks, indicating that the Gd prepared in Example 1 and Comparative Example 1 are not crystallized. 55 Co 17.5 Al 27.5 All powder samples were amorphous.

[0057] SEM image of the amorphous alloy powder prepared in Comparative Example 1 is shown below. Figure 2 As shown, the powder prepared by the gas atomization method has good sphericity.

[0058] Determination of magnetic properties of amorphous alloys using MPMS:

[0059] The (Gd) prepared in Example 1 and Comparative Example 1 0.55 Co 0.175 Al 0.275 ) 38.9 H 61.1 and Gd 55 Co 17.5 Al 27.5 Magnetization curves of powder samples under field-cooled (FC) and zero-field-cooled (ZFC) conditions are shown below. Figure 3 and Figure 6 As shown in Table 1, the Curie temperatures of the samples before and after hydrogen absorption were obtained by taking the first derivative of the field cooling curves. The results were 97 K and 7 K, respectively.

[0060] The (Gd) prepared in Example 1 and Comparative Example 1 0.55 Co 0.175 Al 0.275 ) 38.9 H 61.1 and Gd 55 Co 17.5 Al 27.5 The isothermal magnetization curves of the powder samples are as follows: Figure 4 and Figure 7 As shown.

[0061] based on Figure 4 and Figure 7 The isothermal magnetization curves were obtained, and the magnetic entropy change as a function of temperature for the amorphous alloy powder samples of Example 1 and Comparative Example 1 were calculated using Maxwell's relation, as shown below. Figure 5 and Figure 8 As shown, the magnetic entropy change of the sample increases significantly after hydrogen absorption, with the maximum magnetic entropy change increasing from 9.1 J kg under a 5T external field. -1 K -1 Increased to 18.7 J kg -1 K -1 This represents an increase of 105.5%.

[0062] Example 2

[0063] The chemical formula is (Gd 0.55 Ni 0.175 Al 0.275 ) 41.1 H 58.9 The preparation method of heavy rare earth-based amorphous alloy powder materials includes the following steps:

[0064] (1) Gd, Ni, and Al raw materials with a purity greater than 99.9 wt.% are processed according to the molecular formula Gd 55 Ni 17.5 Al 27.5 The atomic percentage of ingredients is shown.

[0065] (2) Place the raw material weighed in step (1) onto the copper mold inside the electric arc melting furnace, close the cavity, and evacuate the cavity to a vacuum of 5×10⁻⁶. -3 Below Pa, then high-purity argon gas is introduced until the pressure reaches 5 × 10⁻⁶. 4 Pa; First, melt the titanium ingot for 2-3 minutes to further consume the residual oxygen in the cavity. Then, melt the alloy ingot twice with a small current (120-150A), and then melt the alloy ingot three times with a large current (200-250A). Before each melting, the alloy ingot is turned over by the robot arm equipped with the electric arc melting furnace. After the last melting is completed, it is naturally cooled for 20 minutes to obtain a master alloy ingot with uniform composition and small burn loss.

[0066] (3) Remove surface impurities from the master alloy ingot obtained in step (2) and clean it in alcohol using an ultrasonic cleaner for 3 minutes. Crush the cleaned alloy ingot into small pieces, load the alloy ingots into a quartz tube with a bottom aperture of 0.7 mm, and place it into the melting furnace of the ultra-small metal powder preparation device. Close the furnace door and evacuate the cavity to a vacuum of 5 × 10⁻⁶. -3 Below Pa, high-purity argon gas is then introduced until the pressure inside and outside the furnace door is equal. The pressure of the atomizing argon gas flow is set to 8 MPa, and the cooling water temperature is set to 10°C. Under the protection of the argon atmosphere, the induction heating power supply is turned on and the current is gradually increased until the alloy ingot melts. The molten alloy is sucked into the atomizing cylinder below the melting furnace through the graphite nozzle at the bottom of the quartz tube using the pressure difference. In the atomizing cylinder, the molten alloy meets the high-speed argon gas flow and is atomized into fine droplets, which are then quickly solidified into alloy powder. Under the action of the high-speed argon gas flow, the powder falls into the receiving hopper to obtain heavy rare earth-based amorphous alloy powder.

[0067] (4) Take out the alloy powder obtained in step (3) and sieve it with 500 and 600 mesh metal sieves to obtain Gd with a particle size of 25-30 μm. 55 Ni 17.5 Al 27.5 powder;

[0068] (5) Place the amorphous alloy powder sample obtained in step (4) into a Sieverts-type gas-solid reaction test apparatus, raise the temperature of the sample chamber to 200℃ and hold for 30 min, fill the sample chamber with hydrogen gas to a pressure of 5 MPa, and perform isothermal treatment for 35 h. The mass fraction of hydrogen absorbed by the amorphous alloy powder is 1.38%. After conversion to atomic percentage, the molecular formula of the obtained hydrogenated heavy rare earth-based amorphous alloy powder is (Gd 0.55 Ni 0.175 Al0.275 ) 41.1 H 58.9 .

[0069] Comparative Example 2

[0070] The chemical formula is Gd 55 Ni 17.5 Al 27.5 The preparation method of heavy rare earth-based amorphous alloy powder materials includes the following steps:

[0071] (1) Gd, Ni, and Al raw materials with a purity greater than 99.9 wt.% are processed according to the molecular formula Gd 55 Ni 17.5 Al 27.5 The atomic percentage of ingredients is shown.

[0072] (2) Place the raw material weighed in step (1) onto the copper mold inside the electric arc melting furnace, close the cavity, and evacuate the cavity to a vacuum of 5×10⁻⁶. -3 Below Pa, then high-purity argon gas is introduced until the pressure reaches 5 × 10⁻⁶. 4 Pa; First, melt the titanium ingot for 2-3 minutes to further consume the residual oxygen in the cavity. Then, melt the alloy ingot twice with a small current (120-150A), and then melt the alloy ingot three times with a large current (200-250A). Before each melting, the alloy ingot is turned over by the robot arm equipped with the electric arc melting furnace. After the last melting is completed, it is naturally cooled for 20 minutes to obtain a master alloy ingot with uniform composition and small burn loss.

[0073] (3) Remove surface impurities from the master alloy ingot obtained in step (2) and clean it in alcohol using an ultrasonic cleaner for 3 minutes. Crush the cleaned alloy ingot into small pieces, load the alloy ingots into a quartz tube with a bottom aperture of 0.7 mm, and place it into the melting furnace of the ultra-small metal powder preparation device. Close the furnace door and evacuate the cavity to a vacuum of 5 × 10⁻⁶. -3 Below Pa, high-purity argon gas is then introduced until the pressure inside and outside the furnace door is equal. The pressure of the atomizing argon gas flow is set to 8 MPa, and the cooling water temperature is set to 10°C. Under the protection of the argon atmosphere, the induction heating power supply is turned on and the current is gradually increased until the alloy ingot melts. The molten alloy is sucked into the atomizing cylinder below the melting furnace through the graphite nozzle at the bottom of the quartz tube using the pressure difference. In the atomizing cylinder, the molten alloy meets the high-speed argon gas flow and is atomized into fine droplets, which are then quickly solidified into alloy powder. Under the action of the high-speed argon gas flow, the powder falls into the receiving hopper to obtain heavy rare earth-based amorphous alloy powder.

[0074] (4) Take out the alloy powder obtained in step (3) and sieve it with 500 and 600 mesh metal sieves to obtain Gd with a particle size of 25-30 μm. 55 Ni 17.5 Al 27.5 powder.

[0075] The XRD patterns of the alloy powders prepared in Example 2 and Comparative Example 2 are as follows: Figure 9 As shown, the XRD pattern does not show any sharp crystallization peaks, indicating that the powder samples prepared in Example 2 and Comparative Example 2 are both amorphous structures.

[0076] Determination of magnetic properties of amorphous alloys using MPMS:

[0077] The (Gd) prepared by Example 2 and Comparative Example 2 0.55 Ni 0.175 Al 0.275 ) 41.1 H 58.9 and Gd 55 Ni 17.5 Al 27.5 The first derivative of the field-cooled curve of the powder sample was obtained, and the Curie temperatures of the sample before and after hydrogen absorption were 69K and 9K, respectively, as shown in Table 1.

[0078] Based on the (Gd) prepared in Example 2 and Comparative Example 2 0.55 Ni 0.175 Al 0.275 ) 41.1 H 58.9 and Gd 55 Ni 17.5 Al 27.5 The isothermal magnetization curves of the powder samples, and the magnetic entropy change versus temperature curves of the amorphous alloy powder samples of Example 2 and Comparative Example 2, can be calculated using Maxwell's relations, as shown below. Figure 10 and Figure 11 As shown, through Figures 10-11 As can be seen, the magnetic entropy change of the powder sample increased significantly after hydrogen absorption, with the maximum magnetic entropy change increasing from 7.1 J kg under an external field of 5 T. -1 K -1 Increased to 14.6 J kg -1 K -1 This represents an increase of 105.6%.

[0079] Example 3

[0080] The chemical formula is (Dy 0.55 Co 0.2 Al 0.24 Si 0.01 ) 39.5 H 60.5 The preparation method of heavy rare earth-based amorphous alloy powder materials includes the following steps:

[0081] (1) Dy, Co, Al, and Si raw materials with a purity greater than 99.9 wt.% were processed according to the molecular formula Dy 55 Co 20 Al24 Si1 shows the atomic percentage of ingredients;

[0082] (2) Place the raw material weighed in step (1) onto the copper mold inside the electric arc melting furnace, close the cavity, and evacuate the cavity to a vacuum of 5×10⁻⁶. -3 Below Pa, then high-purity argon gas is introduced until the pressure reaches 5 × 10⁻⁶. 4 Pa; First, melt the titanium ingot for 2-3 minutes to further consume the residual oxygen in the cavity. Then, melt the alloy ingot twice with a small current (120-150A), and then melt the alloy ingot three times with a large current (200-250A). Before each melting, the alloy ingot is turned over by the robot arm equipped with the electric arc melting furnace. After the last melting is completed, it is naturally cooled for 20 minutes to obtain a master alloy ingot with uniform composition and small burn loss.

[0083] (3) Remove surface impurities from the master alloy ingot obtained in step (2) and clean it in alcohol using an ultrasonic cleaner for 3 minutes. Crush the cleaned alloy ingot into small pieces, load the alloy ingots into a quartz tube with a bottom aperture of 0.7 mm, and place it into the melting furnace of the ultra-small metal powder preparation device. Close the furnace door and evacuate the cavity to a vacuum of 5 × 10⁻⁶. -3 Below Pa, high-purity argon gas is then introduced until the pressure inside and outside the furnace door is equal. The pressure of the atomizing argon gas flow is set to 8 MPa, and the cooling water temperature is set to 10°C. Under the protection of the argon atmosphere, the induction heating power supply is turned on and the current is gradually increased until the alloy ingot melts. The molten alloy is sucked into the atomizing cylinder below the melting furnace through the graphite nozzle at the bottom of the quartz tube using the pressure difference. In the atomizing cylinder, the molten alloy meets the high-speed argon gas flow and is atomized into fine droplets, which are then quickly solidified into alloy powder. Under the action of the high-speed argon gas flow, the powder falls into the receiving hopper to obtain heavy rare earth-based amorphous alloy powder.

[0084] (4) Take out the alloy powder obtained in step (3) and sieve it using 500 and 600 mesh metal sieves to obtain Dy particles with a particle size of 25-30 μm. 55 Co 20 Al 24 Si1 powder;

[0085] (5) Place the amorphous alloy powder sample obtained in step (4) into a Sieverts-type gas-solid reaction test apparatus, raise the temperature of the sample chamber to 200℃ and hold for 30 min, fill the sample chamber with hydrogen gas to a pressure of 5 MPa, and perform isothermal treatment for 30 h. The mass fraction of hydrogen absorbed by the amorphous alloy powder is 1.42%. After conversion to atomic percentage, the molecular formula of the obtained hydrogenated heavy rare earth-based amorphous alloy powder is (Dy 0.55 Co 0.2 Al 0.24 Si 0.01 ) 39.5 H 60.5 .

[0086] Comparative Example 3

[0087] The chemical formula is Dy 55 Co 20 Al 24 The preparation method of Si1 heavy rare earth-based amorphous alloy powder material includes the following steps:

[0088] (1) Dy, Co, Al, and Si raw materials with a purity greater than 99.9 wt.% were processed according to the molecular formula Dy 55 Co 20 Al 24 Si1 shows the atomic percentage of ingredients;

[0089] (2) Place the raw material weighed in step (1) onto the copper mold inside the electric arc melting furnace, close the cavity, and evacuate the cavity to a vacuum of 5×10⁻⁶. -3 Below Pa, then high-purity argon gas is introduced until the pressure reaches 5 × 10⁻⁶. 4 Pa; First, melt the titanium ingot for 2-3 minutes to further consume the residual oxygen in the cavity. Then, melt the alloy ingot twice with a small current (120-150A), and then melt the alloy ingot three times with a large current (200-250A). Before each melting, the alloy ingot is turned over by the robot arm equipped with the electric arc melting furnace. After the last melting is completed, it is naturally cooled for 20 minutes to obtain a master alloy ingot with uniform composition and small burn loss.

[0090] (3) Remove surface impurities from the master alloy ingot obtained in step (2) and clean it in alcohol using an ultrasonic cleaner for 3 minutes. Crush the cleaned alloy ingot into small pieces, load the alloy ingots into a quartz tube with a bottom aperture of 0.7 mm, and place it into the melting furnace of the ultra-small metal powder preparation device. Close the furnace door and evacuate the cavity to a vacuum of 5 × 10⁻⁶. -3 Below Pa, high-purity argon gas is then introduced until the pressure inside and outside the furnace door is equal. The pressure of the atomizing argon gas flow is set to 8 MPa, and the cooling water temperature is set to 10°C. Under the protection of the argon atmosphere, the induction heating power supply is turned on and the current is gradually increased until the alloy ingot melts. The molten alloy is sucked into the atomizing cylinder below the melting furnace through the graphite nozzle at the bottom of the quartz tube using the pressure difference. In the atomizing cylinder, the molten alloy meets the high-speed argon gas flow and is atomized into fine droplets, which are then quickly solidified into alloy powder. Under the action of the high-speed argon gas flow, the powder falls into the receiving hopper to obtain heavy rare earth-based amorphous alloy powder.

[0091] (4) Take out the alloy powder obtained in step (3) and sieve it using 500 and 600 mesh metal sieves to obtain Dy particles with a particle size of 25-30 μm. 55 Co 20 Al 24 Si1 powder.

[0092] The XRD patterns of the alloy powders prepared in Example 3 and Comparative Example 3 are as follows: Figure 12 As shown, the XRD pattern does not show any sharp crystallization peaks, indicating that the powder samples prepared in Example 3 and Comparative Example 3 are both amorphous structures.

[0093] Determination of magnetic properties of amorphous alloys using MPMS:

[0094] The (Dy) prepared by Example 3 and Comparative Example 3 0.55 Co 0.2 Al 0.24 Si 0.01 ) 39.5 H 60.5 and Dy 55 Co 20 Al 24 The first derivative of the field-cooled curve of the Si1 powder sample was obtained, and the Curie temperatures of the sample before and after hydrogen absorption were 27K and 5K, respectively, as shown in Table 1.

[0095] Based on the (Dy) prepared in Example 3 and Comparative Example 3 0.55 Co 0.2 Al 0.24 Si 0.01 ) 39.5 H 60.5 and Dy 55 Co 20 Al 24 The isothermal magnetization curves of the Si1 powder sample, and the magnetic entropy change versus temperature curves of the amorphous alloy powder samples of Example 3 and Comparative Example 3, can be calculated using Maxwell's relations, as shown below. Figure 13 and Figure 14 As shown. (Through) Figures 13-14 It can be seen that the magnetic entropy change of the powder sample increases significantly after hydrogen absorption, with the maximum magnetic entropy change increasing from 8.5 J kg under an external field of 5 T. -1 K -1 Increased to 15.5J kg -1 K -1 This represents an increase of 82.4%.

[0096] This invention utilizes a magnetic measurement system (MPMS) to determine the temperature-rising magnetization curves (zero field and band field) and isothermal magnetization curves of heavy rare earth-based amorphous alloys, and calculates the Curie temperature (T) of the sample. C ) and magnetic entropy change (-ΔS) M For the calculation process of the relevant parameters, please refer to the literature Annu.Rev.Mater.Sci.2000(30):387-429.

[0097] Table 1 shows the magnetic properties of the amorphous alloy samples obtained in Examples 1-3 and Comparative Examples 1-3.

[0098]

Claims

1. A hydrogenated heavy rare earth-based amorphous alloy powder material, characterized by: The molecular formula of the compound is: (R a T b Al e ) 100-x H x ; wherein, R is a heavy rare earth element, Gd or Dy; T is a transition metal element, Co or Ni; wherein, when R is Gd, 0≤a≤0.6, when R is Dy, 0≤a≤0.6, when T is Co, 0≤b≤0.2, when T is Ni, 0≤b≤0.2, 0.2≤e≤0.3; a+b+e=1, 50≤x≤70; Or the molecular formula is: (R a T b Al e M f ) 100-x H x ; wherein, R is a heavy rare earth element, Gd or Dy; T is a transition metal element, Co or Ni; M is a metalloid element, Si; wherein, 0≤a≤0.6, 0≤b≤0.2, 0.2≤e≤0.3, 0≤f≤0.01, a+b+e+f=1, 50≤x≤70.

2. The method of producing a hydrogenated heavy rare earth-based amorphous alloy powder material according to claim 1, characterized by, comprising the following steps: (1) weighing corresponding raw materials according to the heavy rare earth-based alloy formula; mixing the raw materials and placing them into an electric arc furnace for electric arc smelting under the protection of an inert atmosphere, and obtaining a master alloy ingot after cooling; (2) gas atomization powder preparation: placing the master alloy ingot into a high-frequency smelting furnace to melt the alloy, and when the alloy melt flows into an atomization chamber for gas atomization dispersion, the alloy is classified and sieved after cooling to obtain heavy rare earth-based amorphous alloy powder; (3) isothermal hydrogenation: the amorphous alloy powder obtained in step (2) is subjected to isothermal hydrogenation treatment to obtain hydrogenated heavy rare earth-based amorphous alloy powder material.

3. The method for preparing hydrogenated heavy rare earth-based amorphous alloy powder material according to claim 2, characterized in that: In step (1), the melting process is as follows: the raw materials are placed on a copper mold in an arc melting furnace, the chamber is closed, the chamber is vacuumed to 5x10 - 3 Pa, and then high-purity argon is filled to a gas pressure of 5x10 4 Pa. The titanium ingot is first melted to further remove residual oxygen in the chamber, and then the remaining raw materials are melted to be molten. After the raw materials are molten, the melting is continued for 2-3 min and the heating is stopped. After the alloy is cooled to solidification with the crucible, it is turned over, and the repeated melting is performed 5 times to obtain a master alloy ingot with uniform composition and small loss on ignition.

4. The method of claim 2, wherein the hydrogenated heavy rare earth-based amorphous alloy powder material is prepared by the steps of: In step (2), the gas atomization powder preparation process is: removing the surface oxide layer of the master alloy ingot and cleaning it, loading the alloy ingot into a quartz tube with an open upper end and placing it into a high-frequency smelting furnace of a metal powder preparation device, melting the alloy ingot by induction smelting under the protection of an argon atmosphere, and spraying the alloy melt through a graphite nozzle at the bottom of the quartz tube to meet a high-speed argon gas stream to atomize it into fine droplets. The droplets rapidly solidify into amorphous alloy powder in a closed atomization cylinder. ​ 5. The method of claim 4, wherein the hydrogenated heavy rare earth-based amorphous alloy powder material is prepared by the steps of: The gas atomization powdering conditions are: first, vacuumize the cavity to 5×10 -3 Pa, then fill in the atomization gas argon, the pressure of the atomization argon gas flow is 8 MPa. ​ 6. The method of claim 2, wherein the hydrogenated heavy rare earth-based amorphous alloy powder material is prepared by the steps of: In step (2), the classification and sieving is: placing a bottom disc, a 600-mesh screen, and a 500-mesh screen from bottom to top in order; placing the prepared alloy powder on the 500-mesh screen, covering the top cover, and sieving on a powder sifter for no less than 20 minutes. ​ 7. The method of claim 6, wherein the hydrogenated heavy rare earth-based amorphous alloy powder material is prepared by the steps of: The classification and sieving obtains heavy rare earth-based amorphous alloy powder with a particle size of 25-30 μm. ​ 8. The method of claim 2, wherein the hydrogenated heavy rare earth-based amorphous alloy powder material is prepared by the steps of: In step (3), the isothermal hydrogenation treatment process is: placing the heavy rare earth-based amorphous alloy powder obtained in step (4) into a Sieverts-type gas-solid reaction test device, setting the hydrogen gas pressure in the cavity to 5 MPa, and setting the isothermal temperature to be below the glass transition temperature of the heavy rare earth-based alloy powder. ​ 9. The method of claim 8, wherein the hydrogenated heavy rare earth-based amorphous alloy powder material is prepared by the steps of: The isothermal temperature is 200℃. ​ 10. The method of claim 8, wherein the hydrogenated heavy rare earth-based amorphous alloy powder material is prepared by the steps of: The isothermal time is no less than 26 hours. ​

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