阅读说明：本技术 一种利用高压超声热分解法制备高性能永磁复合材料的方法 (Method for preparing high-performance permanent magnet composite material by using high-pressure ultrasonic thermal decomposition method ) 是由 杨杭福 吴琼 华思昊 葛洪良 于 2021-09-12 设计创作，主要内容包括：本发明公开了一种利用高压超声热分解制备高性能永磁复合材料的方法。本发明的永磁复合材料的化学组成式为A-(1-x)Ln-(x)Fe-(12)O-(19)/Co(Ni),所述化合物中元素A为Sr或Ba元素,Ln为La或Ca金属元素的一种或两张,0.0≤x≤0.3。本发明通过高压超声热分解法制备A-(x)Ln-(1-x)Fe-(12)O-(19)微米级永磁材料,并使用高能球磨将Co和Ni磨成纳米级颗粒,之后在气氛保护条件下,高温高压烧结得到永磁复合材料,该制备方法能够是的纳米铁磁颗粒均匀附着在微米级铁氧体颗粒表面,铁磁交换耦合作用更强,有效提高永磁铁氧体的磁性能,制备方法能够有效降低高温烧结温度与时间,节约能耗。(The invention discloses a method for preparing a high-performance permanent magnet composite material by utilizing high-pressure ultrasonic thermal decomposition. The chemical composition formula of the permanent magnet composite material is A 1‑x Ln x Fe 12 O 19 The element A in the compound is Sr or Ba, Ln is one or two of La or Ca metal elements, and x is more than or equal to 0.0 and less than or equal to 0.3. The invention prepares A by a high-pressure ultrasonic thermal decomposition method x Ln 1‑x Fe 12 O 19 The preparation method can uniformly attach the nano ferromagnetic particles on the surface of the micron ferrite particles, has stronger ferromagnetic exchange coupling effect, and effectively improves the permanent magnetThe magnetic property of the ferrite and the preparation method can effectively reduce the high-temperature sintering temperature and time and save energy consumption.)

1. A method for preparing a high-performance permanent magnet composite material by using a high-pressure ultrasonic thermal decomposition method is characterized by comprising the following steps:

(1) solution preparation: dissolving barium salt or strontium salt, ferric salt, lanthanum salt and calcium salt in water, and fully stirring to obtain a mixed solution;

(2) preparing the permanent magnetic ferrite: atomizing the mixed solution obtained in the step (1) in an air pressure type atomizer consisting of a high-pressure bottle and an atomizing nozzle by utilizing a high-pressure ultrasonic atomizing principle, conveying the atomized mixed solution into a tube furnace under the action of carrier gas and air pressure, evaporating, dehydrating and carrying out a salt-heat reaction under the action of high temperature, and finally conveying the atomized mixed solution onto a collector at the tail end of the tube furnace by the carrier gas to obtain permanent magnetic ferrite micro-particles;

(3) metal nanoparticles: grinding Co or Ni metal into nano metal particles by a high-energy ball mill;

(4) and (3) heat treatment: and (3) carrying out high-pressure heat treatment on the permanent magnetic ferrite obtained in the step (2) and the Co or Ni nano metal particles obtained in the step (3) in a nitrogen or argon atmosphere to obtain the permanent magnetic composite material.

2. The method of claim 1, wherein the salt in step (1) is one or more of nitrate, sulfate or chloride.

3. The method according to claim 1, wherein the gas flow rate in the step (2) is 3 to 6L/min, the carrier gas is an inert gas of argon or nitrogen, and the length of the tube furnace is 1.5 m.

4. The method of claim 1, wherein the core temperature of the tube furnace in step (2) is 800 ℃^oC-900 ^oC, forming a centrosymmetric temperature gradient along the length direction, wherein the permanent magnet is A_1-xLn_xFe₁₂O₁₉In the compound, the element A is Sr or Ba, Ln is one or two of La and Ca metal elements, and x is more than or equal to 0.0 and less than or equal to 0.3.

5. The method as claimed in claim 1, wherein the step (3) uses alumina or zirconia ceramic balls with a ball-to-material ratio of 10:1-20:1 and a ball milling time of 4-8 h.

6. The method of claim 1, wherein the Co or Ni nanoparticles in step (3) have a particle size of about 100 nm to about 300 nm.

7. The method as claimed in claim 1, wherein the mass fraction of the Co or Ni metal nanoparticles in the step (4) is about 5-20% of the total mass of the composite material, and the heat treatment temperature is 500% ^oC -600 ^oCThe pressure is 5-15 Mpa, and the time is 30 min-5 h.

Technical Field

The invention relates to a method for preparing a high-performance permanent magnet composite material by using a high-pressure ultrasonic thermal decomposition method, in particular to a method for preparing a high-performance permanent magnet composite material with low energy consumption.

Background

In recent years, permanent magnetic ferrite materials have been developed rapidly, and especially permanent magnetic ferrite composite materials have attracted extensive attention by virtue of the advantages of large magnetic energy product, stable chemical properties, no toxicity and the like. However, the process flow of the traditional permanent magnetic ferrite composite material prepared by high-temperature solid-phase sintering is complex, and particularly for the permanent magnetic ferrite sintered secondarily, the sintering time is long, the temperature is high, the energy consumption is very high, and the magnetic performance of the prepared material is low.

In order to improve the magnetic property of the permanent magnetic composite material and reduce energy consumption, researchers adopt a sol-gel method to prepare nano-scale and micron-scale permanent magnetic composite materials, so that the uniformity of the materials is improved, the magnetic property of the materials is also improved to a certain extent, but the sol-gel method causes larger pollution and higher cost, so that the method cannot be applied to actual industrial production in a large scale.

The permanent magnetic ferrite material prepared by the high-pressure ultrasonic thermal decomposition method has the advantages that the particle size can be controlled to be 5-10 mu m, the uniformity is good, the magnetic performance is good, the solid-phase sintering is used for carrying out double-phase compounding with metal particles such as Co, Ni and the like, the magnetic performance is further improved, the required sintering temperature and time are greatly reduced, and the energy consumption is reduced.

Disclosure of Invention

The invention aims to provide a method for preparing a high-performance permanent magnet composite material by using a high-pressure ultrasonic thermal decomposition method. Compared with the existing method for preparing the permanent magnet composite material, the method provided by the invention has the advantages of simple process, high reaction speed and low energy consumption.

The invention provides a method for preparing a high-performance permanent magnet composite material by using a high-pressure ultrasonic thermal decomposition method, which comprises the following preparation steps:

(1) solution preparation: dissolving barium salt or strontium salt, ferric salt, lanthanum salt and calcium salt in water, and fully stirring to obtain a mixed solution; (2) preparing the permanent magnetic ferrite: atomizing the mixed solution obtained in the step (1) in an air pressure type atomizer consisting of a high-pressure bottle and an atomizing nozzle by utilizing a high-pressure ultrasonic atomizing principle, conveying the atomized mixed solution into a tube furnace under the action of carrier gas and air pressure, evaporating, dehydrating and carrying out a salt-heat reaction under the action of high temperature, and finally conveying the atomized mixed solution onto a collector at the tail end of the tube furnace by the carrier gas to obtain permanent magnetic ferrite micro-particles; (3) metal nanoparticles: grinding Co or Ni metal into nano metal particles by a high-energy ball mill; (4) and (3) heat treatment: and (3) carrying out high-pressure heat treatment on the permanent magnetic ferrite obtained in the step (2) and the Co or Ni nano metal particles obtained in the step (3) in a nitrogen or argon atmosphere to obtain the permanent magnetic composite material.

Especially, preferably, the salt in the step (1) may be one or more of nitrate, sulfate or chloride.

Particularly, it is preferable that the gas flow rate in the step (2) is 3 to 6L/min, the carrier gas to be transported is an inert gas such as argon, nitrogen, etc., and the length of the tube furnace is 1.5 m.

Particularly, preferably, the central temperature of the tube furnace in the step (2) is 800-_1-xLn_xFe₁₂O₁₉In the compound, the element A is Sr or Ba, Ln is one or two of La and Ca metal elements, and x is more than or equal to 0.0 and less than or equal to 0.3.

In particular, preferably, alumina or zirconia ceramic balls are used in the step (3) with a ball-to-material ratio of

10:1-20:1, and the ball milling time is 4-8 h.

In particular, the particle size of the Co and Ni nanoparticles in the step (3) is preferably about 100-300 nm. Particularly, preferably, the mass fraction of the Co or Ni metal nanoparticles in the step (4) is about 5-20% of the total mass of the composite material, and the heat treatment temperature is 500% ^oC -600 ^oCThe pressure is 5-15 Mpa, and the time is 30 min-5 h.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) nitrate or sulfate is used as a raw material, so that organic salt is avoided, the raw material cost is low, and the experiment is nontoxic;

(2) compared with the traditional solid phase sintering method, the high pressure ultrasonic thermal decomposition method has short reaction time and reduced energy consumption;

(3) the obtained composite material effectively improves the remanence and magnetic energy product of the material because the Co and Ni ferromagnetic nano particles are fully coupled with the surface magnetism of the micron permanent magnetic ferrite.

Drawings

FIG. 1 is a schematic diagram of a high-pressure ultrasonic thermal decomposition device for preparing ferrite materials, 1, an air compressor 2, an air filter 3, a liquid storage tank 4, a pump 5, a flow meter 6, an ultrasonic atomizer 7, a temperature control furnace 8, a quartz tube 9, a powder catcher 10 and a gas washing device.

FIG. 2 Sr produced by thermal decomposition_0.7La_0.3Fe₁₂O₁₉SEM electron micrograph of (1).

Detailed Description

Preparation A is illustrated below with reference to specific examples_1-xLn_xFe₁₂O₁₉Co and A_1-xLn_xFe₁₂O₁₉A method for preparing a Ni permanent magnet composite material.

Example 1

(1) Preparation of A by high pressure ultrasonic thermal decomposition_1-xLn_xFe₁₂O₁₉Precursor, A is strontium, Ln is lanthanum, wherein x =0.3, and Sr is prepared_0.7La_0.3Fe₁₂O₁₉The precursor, the high-pressure ultrasonic thermal decomposition device is shown in figure 1.

Sr (NO)₃)₂、La(NO₃)₃、Fe(NO₃)₃According to a molar ratio of 0.7: 0.3: 12 is prepared into 500mL of metal salt solution with the proportion of 1mol/L, the metal salt solution is poured into a high-pressure bottle, the tube furnace is heated to 800 ℃ at the speed of 10 ℃/min, an atomizer is opened, the internal pressure of high pressure is 10MPa, and N is₂The gas flow rate of (2) was set to 5L/min, and the atomized water mist was transported to a tube furnace by a carrier gas, and the product was collected in a collector at the end of the tube. Putting the collected product into a mortar, grinding until no granular sensation exists, putting a magnet at the bottom of the mortar, pouring the washing liquid by utilizing the magnetic separation principle, and washing for 3 times by using absolute ethyl alcohol. Drying the cleaned product in a vacuum drying oven at 60 deg.C for 12 hr to obtain pure Sr_0.7La_0.3Fe₁₂O₁₉Permanent magnetic particles, as shown in fig. 2.

(2) And (3) grinding the Co metal into particles of 100 nm and 300nm by using a high-energy ball mill with the ball-to-material ratio of 10:1-20:1 and the ball milling time of 4-8 h.

(3) Preparation of Sr by sintering process_0.7La_0.3Fe₁₂O₁₉A permanent magnet/Co composite material prepared by mixing Sr_0.7La_0.3Fe₁₂O₁₉Putting the precursor and Co nano particles into a sintering furnace, introducing nitrogen, and introducing 10MPa of pressure ^oCThe temperature rise rate of/min is increased to 500^oC, sintering for 2h, and slowly cooling to room temperature to obtain Sr_0.7La_0.3Fe₁₂O₁₉The magnetic hysteresis loop of the/Co permanent magnet composite material is measured by using VSM, and the magnetic property of the permanent magnet composite material is obtained by: (BH)_max=4.25MGOe, with uncomplexed Sr_0.7La_0.3Fe₁₂O₁₉In contrast, Sr_0.7La_0.3Fe₁₂O₁₉The magnetic energy product of/Co is improved by 21 percent.

Example 2

(1) Preparation of A by high pressure ultrasonic thermal decomposition_1-xLn_xFe₁₂O₁₉Precursor, A is barium, Ln is calcium, wherein x =0.3, Ba is prepared_0.7Ca_0.3Fe₁₂O₁₉The precursor, the high-pressure ultrasonic thermal decomposition device is shown in figure 1.

Mixing Ba (NO)₃)₂、Ca(NO₃)₂、Fe(NO₃)₃According to a molar ratio of 0.7: 0.3: 12 is prepared into 500mL of metal salt solution with the proportion of 1mol/L, the metal salt solution is poured into a high-pressure bottle, the tube furnace is heated to 800 ℃ at the speed of 10 ℃/min, an atomizer is opened, the internal pressure of high pressure is 10MPa, and N is₂The gas flow rate of (2) was set to 5L/min, and the atomized water mist was transported to a tube furnace by a carrier gas, and the product was collected in a collector at the end of the tube. Putting the collected product into a mortar, grinding until no granular sensation exists, putting a magnet at the bottom of the mortar, pouring the washing liquid by utilizing the magnetic separation principle, and washing for 3 times by using absolute ethyl alcohol. Drying the cleaned product in a vacuum drying oven at 60 deg.C for 12 hr to obtain pure Ba_0.7Ca_0.3Fe₁₂O₁₉Ferrite.

(2) And (3) grinding the Ni metal into particles of 100 nm and 300nm by using a high-energy ball mill with the ball-to-material ratio of 10:1-20:1 and the ball milling time of 4-8 h.

(3) Preparation of Ba by sintering process_0.7Ca_0.3Fe₁₂O₁₉a/Ni permanent magnet composite material prepared from Ba_0.7Ca_0.3Fe₁₂O₁₉Putting the precursor and Ni nano-particles into a sintering furnace, introducing argon, and controlling the pressure to be 20 MPa under the pressure of 10MPa^oThe temperature rise speed of C/min is increased to 600^oC, sintering for 6h, and slowly cooling to room temperature to obtain Ba_0.7Ca_0.3Fe₁₂O₁₉The magnetic hysteresis loop of the/Ni permanent magnet composite material is measured by using VSM, and the magnetic property of the permanent magnet composite material is obtained by: (BH)_max=4.13 MGOe, with uncomplexed Ba_0.7Ca_0.3Fe₁₂O₁₉In contrast, Ba_0.7Ca_0.3Fe₁₂O₁₉The magnetic energy product of/Ni is improved by 12 percent.