A method for preparing CoMnSi-based alloy spherical single crystal particles by using a rapid quenching process

Abstract

The application aims to provide a method for preparing CoMnSi-based alloy spherical single crystal particles by using a rapid quenching process, and the specific steps include: (1) preparing CoMnSi-based alloy particles with a size of 30-300 microns; (2) uniformly mixing the CoMnSi-based alloy particles with boron nitride powder; (3) spheroidizing treatment of the CoMnSi-based alloy particles: annealing the uniformly mixed powder at 1220 DEG C; (4) single crystal treatment of the CoMnSi-based alloy particles: quenching the uniformly mixed powder at 950 DEG C to induce the particles to become single crystal particles at room temperature; (5) tempering the above particles to eliminate the internal stress of the particles. The CoMnSi-based alloy has a molecular formula of CoMn x SiM y , wherein the value range of x is 1-0.8, the value range of y is 0-0.2, and M is selected from one or more of Sc, Ti, Cr, V, Ge, Fe and Ni.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of powder metallurgy, in particular to a method for preparing CoMnSi-based alloy spherical single crystal particles by using a rapid quenching process. BACKGROUND

[0002] Magnetostrictive materials have many excellent physical properties such as high energy density, fast response speed, simple driving mode, and thus have a wide range of applications in the fields of ultrasonic transducers, pressure sensors, micro-drivers, etc. The commercial Terfenol-D alloy is one of them. Terfenol-D alloy has the characteristics of small driving magnetic field, large stress output, and large strain output, and is the most widely used magnetostrictive material. However, its raw materials contain expensive heavy rare earth elements: Tb, Dy, and high cost limits the practical application of the material. At present, there is still an urgent need for a cheap and recyclable magnetostrictive material on the market.

[0003] In recent years, CoMnSi-based alloys have attracted attention as a potential magnetostrictive material. CoMnSi-based alloys are inexpensive, easy to prepare, and not easily oxidized, and have a huge magnetostrictive effect (up to 4000ppm) in their antiferromagnetic-ferromagnetic magnetic phase transition driven by a magnetic field. In order to overcome the intrinsic brittleness of CoMnSi-based alloys, people usually use epoxy resin bonding to prepare oriented and dense CoMnSi-based alloy / epoxy resin composites. However, the CoMnSi-based alloy particles at the present stage are mostly obtained by mechanical crushing of ingots and are mostly polycrystalline. Therefore, the alloy particles in the CoMnSi-based alloy composite exhibit poor single particle performance and are difficult to orient, and the magnetostrictive performance of the material is difficult to improve. In order to prepare CoMnSi-based alloy / epoxy resin composites with high magnetostrictive performance, it is urgent to find a high-performance and easily oriented CoMnSi particle.

[0004] CoMnSi-based alloy spherical single crystal particles are excellent alloy particles suitable for CoMnSi-based alloy / epoxy resin composites. The CoMnSi-based alloy spherical single crystal particles combine the properties of single crystals and the spherical appearance. The properties of single crystals determine that the particles themselves have excellent magnetostrictive properties, and the spherical appearance is conducive to the free rotation of the particles during magnetic field orientation, which is conducive to improving the orientation degree of the composite material. However, there is no report on the preparation of CoMnSi-based alloy single crystal blocks or single crystal particles. At about 920°C, the CoMnSi-based alloy will undergo a martensitic phase transition, which is accompanied by a huge lattice distortion, internal stress and the generation of martensitic twin variants. The martensitic phase transition determines that it is difficult to prepare dense CoMnSi-based alloy single crystals by conventional single crystal preparation methods such as the Czochralski method, the Bridgman method and the like. At present, there is still no conventional technology to prepare CoMnSi-based alloy spherical single crystal particles. SUMMARY

[0005] In view of the deficiencies in the prior art, the purpose of the present application is to provide a preparation method of CoMnSi-based alloy spherical single crystal particles. The method starts from the crystal growth mechanism, utilizes the characteristics of high-temperature quenching and rapid cooling, suppresses the spontaneous generation of martensite nuclei during the martensitic phase transition, thereby avoiding the generation of CoMnSi-based alloy martensite variants, and inducing the growth of CoMnSi-based alloy austenite spherical single crystal particles into martensite spherical single crystal particles. The preparation method has the characteristics of simple and controllable synthesis route, low production cost and high single crystal rate.

[0006] In order to achieve the above-mentioned purpose, the present application provides the following scheme:

[0007] The present application provides a preparation method of CoMnSi-based alloy spherical single crystal particles, whose molecular formula is CoMn x SiM y , wherein the value range of x is 1-0.8, the value range of y is 0-0.2, and M is selected from one or more of Sc, Ti, Cr, V, Ge, Fe and Ni, comprising the following steps:

[0008] a. The CoMn x SiM y alloy ingot is broken into particles of 30-300 μm by mechanical crushing, mortar grinding and the like for standby;

[0009] b. The CoMn x SiM y particles and boron nitride powder are accurately weighed according to the mass ratio of CoMn x SiM y particles to boron nitride of 1:z, and the value range of z is 1-3; the CoMn x SiMy The particles and boron nitride powder are uniformly mixed by mechanical means and put into a sealed quartz tube;

[0010] c. The quartz tube obtained in step b is placed in a high-temperature tube furnace and annealed at 700 ℃ for 0.5-2 h in a flowing hydrogen atmosphere;

[0011] d. The quartz tube obtained in step c is vacuumed and filled with argon to 0.02 MPa for storage;

[0012] e. The quartz tube obtained in step d is placed in a high-temperature furnace and heated from room temperature to 1220 ℃ for 8-10 min, cooled to 1000 ℃ at a rate of 10 ℃ / min for 0.5-2 h, and then cooled to 950 ℃ at a rate of 10 ℃ / min for 0.5-2 h. Finally, the quartz tube is taken out and broken in cold water;

[0013] f. The CoMn x SiM y particles obtained in step e are collected by magnetic attraction;

[0014] g. The CoMn x SiM y particles obtained in step f are put into a quartz tube and vacuumed for storage;

[0015] h. The quartz tube obtained in step g is placed in a high-temperature furnace and heated to 850 ℃ for 0.5-2 h, and then naturally cooled to room temperature to obtain CoMn x SiM y spherical single crystal particles.

[0016] Further, in step a, the CoMn x SiM y alloy ingot can be obtained by arc melting, induction melting, or other ingot preparation methods;

[0017] Further, in step b, the boron nitride powder has a particle size of less than 2 μm;

[0018] Further, in step c, the tube furnace is first vacuumed to below 20 Pa using a mechanical pump, then filled with hydrogen gas to standard atmospheric pressure, and then heated from room temperature;

[0019] Further, in step d, the vacuum is first extracted to below 10 Pa using a mechanical pump, then extracted to 1×10 -3 Pa using a molecular pump, the molecular pump is closed, and argon is filled to 0.6 atmospheric pressure;

[0020] Further, in step f, the CoMnx SiM y The particles are put into a beaker containing anhydrous ethanol, and then put into an ultrasonic cleaning instrument for ultrasonic cleaning, the ultrasonic cleaning time is 1-3 min, the turbid liquid is poured out and clear anhydrous ethanol is added again, and the ultrasonic cleaning is repeated until the liquid in the beaker is transparent and clear.

[0021] Further, in step g, a mechanical pump is used to extract vacuum to below 10 Pa, and then a molecular pump is used to extract vacuum to 1*10 -3 Pa for sealing.

[0022] The present application discloses the following technical effects:

[0023] The CoMnSi-based alloy spherical single crystal particle preparation method of the present application, on the basis of CoMnSi-based alloy parent phase austenitic single crystal, utilizes the rapid quenching process to suppress the spontaneous generation of martensite crystal nucleus during the martensitic phase transformation of the CoMnSi-based alloy, thereby preparing CoMnSi-based alloy 30-300 μm spherical single crystal particles at room temperature. Moreover, this method avoids the problem of cracks on the bulk material and particles caused by the huge internal stress during the martensitic phase transformation, and obtains dense CoMnSi-based alloy spherical single crystal particles. This method has the characteristics of high single crystal particle rate, simplicity, and suitability for large-scale production. The prepared CoMnSi-based alloy spherical single crystal particles are suitable for basic physics research, development of new magnetostrictive materials represented by CoMnSi-based alloy composites, and other fields. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is the SEM characterization graph of the CoMnSi-based alloy particles in Example 1.

[0025] Figure 2 is the EBSD characterization graph of the CoMnSi-based alloy particles in Example 1.

[0026] Figure 3 is the XRD characterization graph of the CoMnSi-based alloy particles before and after orientation in Example 1.

[0027] Figure 4 is the SEM characterization graph of the CoMnSi-based alloy particles in Example 2.

[0028] Figure 5 is the EBSD characterization graph of the CoMnSi-based alloy particles in Example 2. IMPLEMENTATION

[0029] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present application is not limited to the following specific embodiments.

[0030] Unless otherwise defined, all terms used in the present invention, including technical terms and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains. The terms used in the present invention have been used only for the purpose of describing specific embodiments and are not intended to limit the scope of the present invention.

[0031] Unless otherwise specified, each of the various materials, reagents, instruments and apparatuses used in the present invention can be purchased on the market or can be prepared by the existing method. Example 1

[0032] CoNi 0.05 Mn 0.95 Si single crystal particle preparation

[0033] CoNi 0.05 Mn 0.95 Si intermetallic compound (subscript is atomic percentage), mechanical crushing to obtain powder with average size of 50 μm ~ 100 μm or so as raw material. Take 2.5 grams of CoNi 0.05 Mn 0.95 Si intermetallic compound powder and nanometer-sized boron nitride powder are mixed in a weight ratio of 1:2, and are uniformly mixed after mechanical stirring.

[0034] CoNi 0.05 Mn 0.95 Si intermetallic compound / boron nitride powder into a quartz tube, the quartz tube is placed in a high-temperature tube furnace, and is annealed at 700 ℃ for 1 h in a flowing hydrogen atmosphere, and is cooled to room temperature with the furnace; then, the quartz tube is evacuated to 1.0 x 10 -3 Pa, and is sealed after being filled with argon gas to 0.06 MPa, and the quartz tube containing the mixed CoNi 0.05 Mn 0.95 Si intermetallic compound / boron nitride powder is placed into an annealing furnace heated to 1220 ℃ and is kept for 10 min, and is cooled to 1000 ℃ at a cooling rate of 10 ℃ / min and is kept for 1 h, and is cooled to 950 ℃ at a cooling rate of 10 ℃ / min, and the quartz tube is taken out and is rapidly quenched by knocking the tube wall in cooling water.

[0035] CoNi 0.05 Mn 0.95 Si intermetallic compound particles, and CoNi 0.05 Mn 0.95 Si intermetallic compound particles. The washed CoNi 0.05 Mn 0.95 Si intermetallic compound particles into a quartz tube, and the quartz tube is evacuated to 1.0 x 10 -3Pa. The quartz tube was put into an annealing furnace heated to 800℃ and kept for 2h, and then cooled to room temperature.

[0036] Figure 1 CoNi 0.05 Mn 0.95 Scanning electron microscope (SEM) image of the intermetallic compound particles of Si. The particle size is in the range of 30μm to 100μm. Figure 2 CoNi 0.05 Mn 0.95 Electron backscatter diffraction (EBSD) analysis of the intermetallic compound particles of Si. It can be seen that the grain boundary of the particles shows a single color, indicating that the particles are single crystals. Figure 3 CoNi 0.05 Mn 0.95 The particles of Si achieved good orientation under the applied magnetic field. Example 2

[0037] CoNi 0.05 Mn 0.95 The intermetallic compound of Si (subscript is atomic percentage) was obtained by a melting method, and the powder with an average size of about 50μm to 100μm was obtained by mechanical crushing as a raw material. 2.5 grams of CoNi 0.05 Mn 0.95 The intermetallic compound powder of Si and the nano-sized boron nitride powder were mixed uniformly by mechanical stirring in a weight ratio of 1:2.

[0038] The mixed CoNi 0.05 Mn 0.95 Si intermetallic compound / boron nitride powder was put into a quartz tube, and the quartz tube was placed in a high-temperature tube furnace in a flowing hydrogen environment at 700℃ for 1h, and then cooled to room temperature. Subsequently, the quartz tube was vacuumed to 1.0×10 -3 Pa, and then sealed after the argon gas was introduced to 0.06MPa. The quartz tube containing the mixed CoNi 0.05 Mn 0.95 Si intermetallic compound / boron nitride powder was put into an annealing furnace heated to 1220℃ and kept for 10min, and then cooled to 1000℃ at a cooling rate of 10℃ / min for 1h, cooled to 950℃ at a cooling rate of 10℃ / min, cooled to 850℃ at a cooling rate of 1℃ / min and kept for 1h, and then cooled with the furnace. The CoNi 0.05 Mn 0.95 Si intermetallic compound powder, and the CoNi 0.05 Mn 0.95Si intermetallic compound particles.

[0039] Figure 4 CoNi 0.05 Mn 0.95 Scanning electron microscope image of Si intermetallic compound particles with a size of 30-100 μm. Figure 5 CoNi 0.05 Mn 0.95 Electron backscatter diffraction (EBSD) analysis of Si intermetallic compound particles. It can be seen that the grains on the cross section of the particles exhibit a banded feature, which indicates that the particles have twin variants, and exhibit a polycrystalline state at room temperature. Example 3

[0040] CoFe 0.05 Mn 0.95 Preparation of Si single crystal particles

[0041] CoFe 0.05 Mn 0.95 Si intermetallic compound (subscript: atomic percentage) was obtained by a melting method, and mechanically broken to obtain a powder with an average size of about 50-100 μm as a raw material. 2.5 g of CoFe 0.05 Mn 0.95 Si intermetallic compound powder was mixed with nano-sized boron nitride powder at a weight ratio of 1:2, and uniformly mixed after mechanical stirring.

[0042] CoFe 0.05 Mn 0.95 Si intermetallic compound / boron nitride powder was placed in a quartz tube, and the quartz tube was placed in a high-temperature tube furnace, annealed at 700°C for 1 h in a flowing hydrogen atmosphere, and cooled to room temperature with the furnace; then, the quartz tube was evacuated to 1.0 x 10 -3 Pa, and sealed after argon was introduced to 0.06 MPa. The quartz tube containing the mixed CoFe 0.05 Mn 0.95 Si intermetallic compound / boron nitride powder under argon protection was placed in an annealing furnace heated to 1220°C, and held for 10 min, then cooled to 1000°C at a rate of 10°C / min, held for 1 h, cooled to 950°C at a rate of 10°C / min, and the quartz tube was removed and rapidly quenched in cooling water by knocking the tube wall.

[0043] CoFe 0.05 Mn 0.95 Si intermetallic compound powder was obtained by ultrasonic cleaning. 0.05 Mn 0.95 Si intermetallic compound particles. The cleaned CoFe 0.05 Mn0.95 Si intermetallic compound particles were put into a quartz tube, which was evacuated to 1.0 x 10 -3 Pa and sealed. The quartz tube was put into an annealing furnace heated to 800°C and held for 2h, and then cooled to room temperature in the furnace.

[0044] CoFe 0.05 Mn 0.95 Si alloy particles / nitrogen boride mixed powder, CoFe 0.05 Mn 0.95 Si alloy particles were characterized by electron backscatter diffraction (EBSD). CoFe 0.05 Mn 0.95 Si alloy particles were single-crystal. According to the manufacturing method of the metal particles of the present application, it was confirmed that CoFe 0.05 Mn 0.95 Si alloy single-crystal particles.

[0045] The foregoing description of the disclosed embodiments enables a person skilled in the art to carry out or use the present application. The present application will not be limited to the embodiments shown herein, but will be construed in the widest scope possible in accordance with the principles and novel features disclosed herein.

Claims

1. A method for producing CoMnSi-based alloy spherical single-crystal particles by a rapid quenching process, characterized by, The method comprises the following steps: a. CoMn x SiM y The alloy ingot is broken into 30-300 μm particles by mechanical crushing or mortar grinding for standby use. b. CoMn x SiM y The particles and boron nitride powder are mixed uniformly by mechanical means and placed in a quartz tube with one end sealed, and the boron nitride powder has a particle size of less than 2 μm. x SiM y The particles and boron nitride powder are mixed uniformly by mechanical means and placed in a quartz tube with one end sealed, and the boron nitride powder has a particle size of less than 2 μm. x SiM y The particles and boron nitride powder are mixed uniformly by mechanical means and placed in a quartz tube with one end sealed, and the boron nitride powder has a particle size of less than 2 μm. c. annealing the quartz tube obtained in step b in a high-temperature tube furnace at 700 ℃ for 0.5-2 h in a hydrogen flow environment; d. vacuumizing the quartz tube obtained in step c and sealing it by filling argon to 0.06 MPa; e. placing the quartz tube obtained in step d into a high-temperature furnace, heating it from room temperature to 1220 ℃ for 8-10 min, cooling it to 1000 ℃ at a rate of 10 ℃ / min for 0.5-2 h, cooling it to 950 ℃ at a rate of 10 ℃ / min for 0.5-2 h, and finally taking out the quartz tube and rapidly quenching it by knocking the tube wall in cold water; f. CoMn obtained in step e is collected using a magnet attraction method x SiM y The particles are then put into an ultrasonic cleaning instrument to separate and clean the alloy powder. g. CoMn obtained in step f is mixed with SiM x SiM y The particles are put into a quartz tube, vacuumed and sealed. h. The quartz tube obtained in step g is placed in a high-temperature furnace and heated to 850°C for 0.5-2 h, and then naturally cooled to room temperature to obtain CoMn x SiM y spherical single-crystal particles.

2. The method for preparing CoMnSi-based alloy spherical single-crystal particles by using a rapid quenching process according to claim 1, characterized in that: The CoMnSi-based alloy has a molecular formula of CoMn x SiM y， wherein x is in a range of 1-0.8, y is in a range of 0-0.2, and M is selected from one or more of Sc, Ti, Cr, V, Ge, Fe, and Ni.

3. The method for preparing CoMnSi-based alloy spherical single-crystal particles by using a rapid quenching process according to claim 1, characterized in that: In step a, CoMn x SiM y The alloy ingot is obtained by an ingot preparation method of an arc melting method or an induction melting method.

4. The method for preparing CoMnSi-based alloy spherical single-crystal particles by using a rapid quenching process according to claim 1, characterized in that: In step d, first, a mechanical pump is used to extract vacuum to 10 Pa or less, and then a molecular pump is used to extract vacuum to 1 x 10 -3 Pa or less, the molecular pump is closed, and argon is filled to 0.6 atm.

5. The method for preparing CoMnSi-based alloy spherical single-crystal particles by using a rapid quenching process according to claim 1, characterized in that: In step g, first, a mechanical pump is used to extract vacuum to 10 Pa or less, and then a molecular pump is used to extract vacuum to 1 x 10 -3 Pa for storage.

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