CN111653405A - Preparation method of low-nitrogen RE-Fe-B series permanent magnet material and product thereof - Google Patents

Preparation method of low-nitrogen RE-Fe-B series permanent magnet material and product thereof Download PDF

Info

Publication number
CN111653405A
CN111653405A CN202010610108.8A CN202010610108A CN111653405A CN 111653405 A CN111653405 A CN 111653405A CN 202010610108 A CN202010610108 A CN 202010610108A CN 111653405 A CN111653405 A CN 111653405A
Authority
CN
China
Prior art keywords
hydrogen
nitrogen
sintering
mixed gas
permanent magnet
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202010610108.8A
Other languages
Chinese (zh)
Inventor
兰文辉
孔维峰
邹锦延
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xiamen Tungsten Co Ltd
Fujian Changting Jinlong Rare Earth Co Ltd
Original Assignee
Xiamen Tungsten Co Ltd
Fujian Changting Jinlong Rare Earth Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Xiamen Tungsten Co Ltd, Fujian Changting Jinlong Rare Earth Co Ltd filed Critical Xiamen Tungsten Co Ltd
Priority to CN202010610108.8A priority Critical patent/CN111653405A/en
Publication of CN111653405A publication Critical patent/CN111653405A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
    • H01F1/0577—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together sintered
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/02—Compacting only
    • B22F3/04—Compacting only by applying fluid pressure, e.g. by cold isostatic pressing [CIP]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/10—Sintering only
    • B22F3/1003—Use of special medium during sintering, e.g. sintering aid
    • B22F3/1007—Atmosphere
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/02—Making metallic powder or suspensions thereof using physical processes
    • B22F9/023—Hydrogen absorption
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/02—Making metallic powder or suspensions thereof using physical processes
    • B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
    • H01F41/0266—Moulding; Pressing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • B22F2003/248—Thermal after-treatment

Abstract

The invention provides a preparation method of a low-nitrogen RE-Fe-B series permanent magnet material and a product prepared by the same, wherein the preparation method comprises the steps of vacuum rapid hardening of raw materials for preparing the RE-Fe-B series permanent magnet material, hydrogen crushing, jet milling, profiling and sintering, wherein the jet milling is carried out by using mixed gas of nitrogen and hydrogen or nitrogen and oxygen, the volume of the hydrogen is 0.01-2% of the volume of the mixed gas, and the mass of the oxygen is 0.01-0.2% of the mass of the mixed gas. The preparation method of the invention does not need to adopt low-temperature nitrogen or argon or increase the investment of a refrigerator and the consumption of a large amount of electricity fee, does not need to adopt argon in the jet milling process, obviously improves the jet milling crushing efficiency, has low production cost and high efficiency, and is beneficial to industrial production. The product prepared by the method keeps the carbon content below 600 mu g/g, simultaneously controls the nitrogen content below 300 mu g/g, and improves the corrosion resistance and the magnetic performance index.

Description

Preparation method of low-nitrogen RE-Fe-B series permanent magnet material and product thereof
Technical Field
The invention relates to a preparation method of a low-nitrogen RE-Fe-B series permanent magnet material and a product thereof.
Background
RE-Fe-B series permanent magnetic material RE composed of rare earth elements2Fe14The B type compound is a main phase and is widely applied to the fields of energy, transportation, machinery, medical treatment, computers, household appliances and the like. Generally, the low-nitrogen RE-Fe-B permanent magnet material is mainly an RE-Fe-B permanent magnet material with the nitrogen content controlled within 300 mu g/g (ppm).
In the prior art, when RE-Fe-B series permanent magnet materials such as sintered neodymium iron boron (NdFeB) are prepared, a casting process or a rapid hardening flake process is generally adopted, then ingot casting alloy or the rapid hardening flake is crushed into coarse powder through a hydrogen explosion process or a crusher, the coarse powder is prepared into fine powder through airflow grinding, and the whole process needs nitrogen protection. The nitrogen content of the finally obtained material is in the range of 400-2000 mu g/g, the nitrogen content can only be ensured to be in the range of 436-675 mu g/g under the disclosed fully-sealed process condition, and the high nitrogen content can influence the performance improvement of the magnet and the improvement of the corrosion resistance.
CN101615462A discloses a method for preparing a Re-Fe-B permanent magnet material containing trace nitrogen, wherein a special hydrogen absorption dehydrogenation process and a low-temperature nitrogen or argon crushing and air flow grinding process are adopted, so that the nitrogen content of the RE-Fe-B permanent magnet material can be controlled to be less than or equal to 300 mu g/g. The method needs to adopt low-temperature nitrogen or argon, the temperature of the nitrogen or argon needs to be kept less than or equal to 10 ℃, the investment of a refrigerator and the consumption of a large amount of electricity charges need to be increased, and the process cost is overhigh. Adopt argon gas jet mill, because argon gas molecular weight is bigger than nitrogen gas, the difficult compression of argon gas, the same model air compressor machine, argon gas air current speed is less, causes production efficiency to descend and the air compressor machine burden is big, and argon gas cost is too high simultaneously, causes the gas consumption cost to increase.
Disclosure of Invention
The invention aims to overcome the defects that the prior preparation method of the low-nitrogen RE-Fe-B permanent magnetic material needs to adopt low-temperature nitrogen, needs to increase the investment of a refrigerator and consume a large amount of electricity so as to cause overhigh process cost, needs to adopt argon so as to cause reduction of production efficiency, large burden of an air compressor, overhigh cost and the like, and provides the preparation method of the low-nitrogen RE-Fe-B permanent magnetic material and the low-nitrogen RE-Fe-B permanent magnetic material prepared by the same. The preparation method of the invention does not need to adopt low-temperature nitrogen or argon, does not need to increase the investment of a refrigerator and the consumption of a large amount of electricity fee, does not need to adopt argon in the jet milling process, obviously improves the crushing efficiency of the jet mill in the preparation process, has low production cost and high production efficiency, and is beneficial to industrial production. The low-nitrogen RE-Fe-B series permanent magnetic material prepared by the preparation method can keep the carbon content below 600 mu g/g, the nitrogen content below 300 mu g/g, and the corrosion resistance and the magnetic performance indexes (such as remanence, intrinsic coercive force and the like) of the obtained permanent magnetic material are improved.
The excessive nitrogen content in the RE-Fe-B permanent magnet material affects the performance improvement of the magnet and the improvement of the corrosion resistance, and those skilled in the art are always seeking various ways to try to reduce the nitrogen content in the finally obtained permanent magnet material, such as adding low-temperature argon gas in the CN101615462A during the crushing and jet milling process, but still have the problems of excessive cost, low production efficiency, etc. Through a large number of experiments, the inventor unexpectedly discovers that in the process of preparing the RE-Fe-B series permanent magnet material, when hydrogen or mixed gas formed by oxygen and nitrogen is used as circulating gas of the jet mill, the nitrogen content of the obtained RE-Fe-B series permanent magnet material can be controlled below 300 mug/g without changing the conditions of other existing preparation processes, so that the low-nitrogen RE-Fe-B series permanent magnet material is prepared; meanwhile, the carbon content can be controlled below 600 mug/g, the corrosion resistance and magnetic performance indexes of the obtained permanent magnet material can be improved, the jet mill crushing efficiency is obviously improved, and the process cost is reduced.
In order to solve the technical problem, the invention provides a preparation method of a low-nitrogen RE-Fe-B series permanent magnet material, which comprises the steps of vacuum rapid hardening of raw materials for preparing the RE-Fe-B series permanent magnet material, hydrogen crushing, jet milling, compression molding and sintering,
the jet mill is carried out by using a mixed gas of nitrogen and hydrogen or a mixed gas of nitrogen and oxygen, wherein the volume of the hydrogen accounts for 0.01-2% of the volume of the mixed gas of the nitrogen and the hydrogen, and the mass of the oxygen accounts for 0.01-0.2% of the mass of the mixed gas of the nitrogen and the oxygen. The inventor finds in experiments that if the volume of hydrogen is higher than 2%, the hydrogen is easy to combust and causes explosion; if the volume of hydrogen is less than 0.01%, the nitrogen content of the final product may exceed 300. mu.g/g, resulting in a decrease in magnetic properties and corrosion resistance of the final product. If the oxygen mass percentage is higher than 0.2%, the product is easy to oxidize, so that the magnetic performance and the corrosion resistance of the product are reduced; if the mass ratio of the oxygen is less than 0.01%, the nitrogen content of the prepared final product can exceed 300 ug/g.
In the invention, the composition and proportion of the raw materials for preparing the RE-Fe-B permanent magnetic material can be conventional in the field as long as the RE-Fe-B permanent magnetic material can be prepared; for example, it may include rare earth elements, iron (Fe), and boron (B), and may further include one or more of other elements such as aluminum (Al), copper (Cu), cobalt (Co), gallium (Ga), niobium (Nb), titanium (Ti), molybdenum (Mo), vanadium (V), and zirconium (Zr). In a preferred embodiment of the present invention, the raw materials for preparing the RE-Fe-B series permanent magnetic material comprise 31% PrNd, 0.6% Dy, 0.8% Ho, 0.98% B, 0.5% Al, 0.2% Cu, 0.13% Ga, 0.2% Nb, and the balance Fe, wherein the percentages are mass percentages.
In the present invention, the rare earth element may be, for example, one or more of lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), yttrium (Y), and/or may further include a mixed rare earth such as PrNd.
In the present invention, the misch metal may be conventional in the art, and may generally refer to a misch metal (alloy) formed by mixing different rare earth elements.
In the present invention, the vacuum rapid solidification step may be conventional in the art, and may include, for example, a step of melting the raw material under vacuum conditions to produce a rapid solidification flake. Wherein the vacuum condition may be a vacuum condition conventionally defined in the art, for example, maintaining a vacuum degree below 30 Pa. The smelting may be carried out by methods conventional in the art, the purpose of which is mainly to melt the raw materials into molten steel, so that the alloy may be obtained by subsequent cooling, and the smelting may be carried out, for example, in a smelting furnace. After smelting, the method can also comprise the steps of casting and/or cooling, wherein the casting and cooling are generally carried out under the protection of an argon environment. The resulting quick set flakes may be typically quick set melt spun alloy flakes that appear silvery white. The sheet thickness of the rapid hardening melt-spun alloy sheet may be generally in the range of 0.2 to 0.4 mm.
In the present invention, the step of hydrogen-crushing may be conventional in the art, and for example, may include a step of hydrogen-absorbing and crushing the rapidly solidified sheet obtained as described above. Wherein the hydrogen absorption can be that the quick-setting sheet is put into a hydrogen crushing furnace to absorb hydrogen, and the quick-setting sheet is crushed to obtain coarse powder. Before the quick-setting sheet is put into a hydrogen crushing furnace, negative pressure leak detection is generally carried out to keep the pressure rise rate less than 10Pa/min, so that the air tightness of the hydrogen crushing furnace is kept good. In the hydrogen absorption process, the pressure of the reaction vessel of the hydrogen pulverizer is usually controlled to be positive pressure, and the hydrogen content in the coarse powder (hydrogen pulverized powder) obtained after hydrogen pulverization is controlled to be 1200 μ g/g or less, for example, 815 μ g/g. The inventor finds that if the pressure of the reaction kettle of the hydrogen crushing furnace is controlled to be negative pressure in the experimental process, nitrogen in the air can contact with the raw materials, and the nitrogen content of the finally obtained product is influenced. Furthermore, the inventors have found that when the hydrogen content in the coarse powder (hydrogen crumbled powder) obtained after hydrogen crumbling is controlled to be higher than 1200. mu.g/g, the finally produced product is liable to crack, resulting in its rejection.
In the present invention, in the jet milling process, the volume of the hydrogen gas may be 0.15% of the volume of the mixed gas of the nitrogen gas and the hydrogen gas. The percentage of the mass of the oxygen gas to the mass of the mixed gas of the nitrogen gas and the oxygen gas may be 0.025%. The purpose of the jet mill is primarily to pulverize the hydrogen powder into a fine powder, which may have a particle size D50 of 2-5 μm, for example 4.3. mu.m. In a preferred embodiment of the invention, a mixed gas of nitrogen and hydrogen is used as the circulating process gas of the jet mill, the volume of the hydrogen accounts for 0.15 percent of the total mixed volume, the jet mill grinds the coarse powder (hydrogen crushed powder) obtained after hydrogen crushing into fine powder, the particle size D50 of the fine powder is 4.3 mu m, and the production efficiency of the jet mill is improved by about 15 percent.
In the present invention, the step of profiling (press forming) may be conventional in the art, and for example, profiling may be performed under the condition that the oriented magnetic field strength is higher than 1.4T. The profiling can be carried out generally using a sample-forming press. The pressed compact obtained after pressing can be pressed by isostatic pressing or non-isostatic pressing, and the pressure of the isostatic pressing can be 180 +/-20 MPa.
In the present invention, the sintering step may be conventional in the art, and for example, may include a step of sintering the product after the jet milling under vacuum, and the vacuum degree may be controlled to be lower than 1Pa, and it is found in the experiment that when the vacuum degree is controlled to be higher than 1Pa, the final product does not reach the level of trace nitrogen. The sintering may be the end of the sintering degassing stage and the beginning of the sintering stage. The temperature of the sintering may be 1050 ± 20 ℃.
In the invention, the sintering process also comprises an aging step. The ageing step may be conventional in the art and may for example comprise a primary ageing step at a temperature of 910 + -50 deg.C and a secondary ageing step at a temperature of 530 + -50 deg.C.
In a preferred embodiment of the present invention, the method for preparing the low-nitrogen RE-Fe-B permanent magnetic material comprises the following steps:
(1) vacuum rapid solidification: smelting raw materials for preparing RE-Fe-B series permanent magnet materials, wherein the smelting is vacuumizing, heating and drying the materials, vacuumizing to less than or equal to 30Pa, and then casting and cooling in an argon environment to obtain a quick-setting sheet with the thickness of 0.2-0.4 mm; the raw materials for preparing the RE-Fe-B series permanent magnetic material comprise 31% of PrNd, 0.6% of Dy, 0.8% of Ho, 0.98% of B, 0.5% of Al, 0.2% of Cu, 0.13% of Ga, 0.2% of Nb and the balance of Fe in percentage by mass;
(2) hydrogen disruption (also known as hydrogen disruption to make meal): carrying out negative pressure leak detection on the hydrogen crushing furnace, keeping the pressure rise rate of the hydrogen crushing furnace less than 10Pa/min, then carrying out hydrogen crushing and hydrogen absorption, controlling the pressure of a reaction kettle in the hydrogen crushing furnace to be positive pressure, and controlling the hydrogen content of hydrogen crushed powder obtained after hydrogen crushing to be 815 mug/g;
(3) jet mill (micro-pulverization): the mixed gas of nitrogen and hydrogen is used as circulating process gas of the jet mill, the volume of the hydrogen accounts for 0.15 percent of the volume of the total mixed gas, the jet mill grinds the hydrogen into fine powder, and the granularity D50 of the fine powder is 4.3 mu m;
(4) profiling: pressing into a pressed compact by using a sampling forming press, wherein the oriented magnetic field intensity is more than 1.4T, and the pressed compact is pressed by isostatic pressing, and the pressure of the isostatic pressing is 180 MPa;
(5) sintering and aging: after sintering treatment, the sintering degassing section is finished, the vacuum degree is controlled to be less than 1Pa, the sintering temperature is 1050 ℃, and then primary aging 910 ℃ and secondary aging 530 ℃ are carried out.
In a preferred embodiment of the present invention, the method for preparing the low-nitrogen RE-Fe-B permanent magnetic material comprises the following steps:
(1) vacuum rapid solidification: smelting raw materials for preparing RE-Fe-B series permanent magnet materials, wherein the smelting is vacuumizing, heating and drying the materials, vacuumizing to less than or equal to 30Pa, and then casting and cooling in an argon environment to obtain a quick-setting sheet with the thickness of 0.2-0.4 mm; the raw materials for preparing the RE-Fe-B series permanent magnetic material comprise 31% of PrNd, 0.6% of Dy, 0.8% of Ho, 0.98% of B, 0.5% of Al, 0.2% of Cu, 0.13% of Ga, 0.2% of Nb and the balance of Fe in percentage by mass;
(2) hydrogen crushing: carrying out negative pressure leak detection on the hydrogen crushing furnace, keeping the pressure rise rate of the hydrogen crushing furnace less than 10Pa/min, then carrying out hydrogen crushing and absorbing, controlling the pressure of a reaction kettle in the hydrogen crushing furnace to be positive pressure, and controlling the hydrogen content of hydrogen crushed powder obtained after hydrogen crushing to be 815 mug/g;
(3) and (3) jet milling: the mixed gas of nitrogen and oxygen is used as circulating process gas of the jet mill, the mass percentage of the oxygen in the total mixed gas is 0.025%, the jet mill grinds the hydrogen powder into fine powder, and the granularity D50 of the fine powder is 4.3 mu m;
(4) profiling: pressing into a pressed compact by using a sampling forming press, wherein the oriented magnetic field intensity is more than 1.4T, and the pressed compact is pressed by isostatic pressing, and the pressure of the isostatic pressing is 180 MPa;
(5) sintering and aging: after sintering treatment, the sintering degassing section is finished, the vacuum degree is controlled to be less than 1Pa, the sintering temperature is 1050 ℃, and then primary aging 910 ℃ and secondary aging 530 ℃ are carried out.
In order to solve the technical problem, the invention also provides a product (the low-nitrogen RE-Fe-B permanent magnetic material) prepared by the preparation method of the low-nitrogen RE-Fe-B permanent magnetic material.
In the present invention, the "comprising or including" may mean that other components exist in addition to the components listed later; it may also mean "consisting of … …", i.e. including only the ingredients listed later without the presence of other ingredients.
On the basis of the common knowledge in the field, the above preferred conditions can be combined randomly to obtain the preferred embodiments of the invention.
The reagents and starting materials used in the present invention are commercially available.
The positive progress effects of the invention are as follows: the preparation method of the invention does not need to adopt low-temperature nitrogen or argon, does not need to increase the investment of a refrigerator and the consumption of a large amount of electricity fee, does not need to adopt argon in the jet milling process, obviously improves the crushing efficiency of the jet mill in the preparation process, has low production cost and high production efficiency, and is beneficial to industrial production. The low-nitrogen RE-Fe-B series permanent magnetic material prepared by the preparation method has the advantages that the nitrogen content can be controlled below 300 mu g/g, the carbon content can be controlled below 600 mu g/g, and the corrosion resistance and the magnetic performance indexes (such as remanence, intrinsic coercive force and the like) of the obtained permanent magnetic material are improved. In a preferred embodiment of the present invention, the obtained low-nitrogen RE-Fe-B permanent magnetic material has a carbon content of 460 μ g/g and a nitrogen content of 218 μ g/g, and the magnetic properties of the obtained permanent magnetic material include Br of 13.1KGs, Hcj of 22Koe, and Hk/Hcj of 98.8%.
Detailed Description
The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.
EXAMPLE 1 preparation of Low-Nitrogen RE-Fe-B permanent magnet Material
1. Material preparation and vacuum quick setting: preparing materials from raw materials, wherein the raw materials comprise 31% of PrNd, 0.6% of Dy, 0.8% of Ho, 0.98% of B, 0.5% of Al, 0.2% of Cu, 0.13% of Ga, 0.2% of Nb and the balance of Fe (the percentages are mass percentages), smelting the prepared materials to melt the prepared materials, wherein the smelting is vacuumizing, heating and drying the materials, vacuumizing to less than or equal to 30Pa, and then carrying out casting and cooling processes in the argon environment protection to obtain a silvery white quick-setting melt-spun alloy sheet, and the thickness of the sheet is 0.2-0.4 mm;
2. hydrogen crushing to prepare coarse powder (hydrogen crushing powder): firstly, carrying out negative pressure leak detection on a hydrogen crushing furnace, keeping the pressure rise rate of the hydrogen crushing furnace less than 10Pa/min, then carrying out a hydrogen crushing and absorbing process, controlling the pressure of a reaction kettle in the hydrogen crushing furnace to be positive pressure, and controlling the hydrogen content of hydrogen crushed powder obtained after hydrogen crushing to be 815 mug/g;
3. performing airflow grinding and micro-crushing: a mixed gas formed by nitrogen and hydrogen is used as circulating process gas of the jet mill, the volume of the hydrogen accounts for 0.15 percent of the total mixed volume, the jet mill grinds hydrogen into fine powder, the granularity D50 of the fine powder is 4.3 mu m, the production efficiency of the jet mill is improved by about 15 percent (the yield obtained after the jet mill is 400kg/h, the yield obtained by the jet mill by adopting the traditional method (namely under the condition of comparative example 1) is 347.8kg/h, and the production efficiency is (400-347.8)/347.8 is 15 percent);
4. profiling: pressing into a pressed blank by using a sampling forming press, wherein the oriented magnetic field intensity of the sampling forming press is more than 1.4T, and then performing isostatic pressing on the obtained pressed blank, wherein the isostatic pressing pressure is 180 MPa;
5. and (3) sintering: after sintering treatment, the sintering degassing section is finished and the sintering section is started, the vacuum degree is controlled to be less than 1Pa, the sintering temperature is 1050 ℃, and then primary aging 910 ℃ and secondary aging 530 ℃ are carried out;
6. magnetic properties the magnetic properties were measured with a PFM pulsed magnetic field magnetometer with Br 13.1KGs, Hcj 22KOe and Hk/Hcj 98.8%. And detecting the carbon content and the nitrogen content of the blank by using an oxygen nitrogen hydrogen analyzer, wherein the carbon content is 460 mu g/g, and the nitrogen content is 218 mu g/g.
7. The corrosion resistance test of the permanent magnet material adopts a highly accelerated life test box for short-term detection, the temperature of the high-speed aging test box is 120 ℃, the humidity is 100 percent RH, and the pressure is 0.2 MPa. The results obtained are shown in table 1 below. As can be seen from the table, the permanent magnet material prepared in this example has good corrosion resistance, while the permanent magnet material prepared in comparative example 1 has poor corrosion resistance.
TABLE 1
Example 1 Comparative example 1
Time (h) Weight loss (mg/cm)2) Weight loss (mg/cm)2)
24 1 2
48 2 4
72 2 8
96 3 12
120 4 15
144 6 19
168 7 26
192 8 35
216 8 48
240 9 60
Example 2
In step 3 of example 1, the gas in the jet mill circulation process was replaced with a mixed gas containing 0.025% (oxygen mass percent of the whole mixed gas) of oxygen and nitrogen, and the rest steps were not changed.
The magnetic property of the final product was measured by a PFM pulsed magnetic field magnetometer with Br 13.07KGs, Hcj 20.8KOe, and Hk/Hcj 98.6%. And detecting the carbon content and the nitrogen content of the blank of the obtained product by using an oxygen-nitrogen-hydrogen analyzer, wherein the carbon content is 560 mu g/g, and the nitrogen content is 287 mu g/g.
Comparative example 1
In step 3 of example 1, the mill cycle process gas was replaced with nitrogen only, and the remaining steps were unchanged.
The magnetic property of the final product was measured by a PFM pulsed magnetic field magnetometer with Br 13.08KGs, Hcj 21KOe, and Hk/Hcj 97.6%. The carbon content and the nitrogen content of the blank of the obtained product are detected by an oxygen nitrogen hydrogen analyzer, the carbon content is 755 mu g/g, and the nitrogen content is 462 mu g/g.
Comparative example 2
In step 3 of example 1, the process gas for the jet mill recycle was replaced with argon as an inert gas, and the remaining steps were unchanged.
The magnetic property of the final product was measured by a PFM pulsed magnetic field magnetometer with Br 13.01KGs, Hcj 20.4KOe and Hk/Hcj 98.2%. And detecting the carbon content and the nitrogen content of the blank of the obtained product by using an oxygen nitrogen hydrogen analyzer, wherein the carbon content is 635 mu g/g, and the nitrogen content is 290 mu g/g.
Comparative example 3
In step 2 of example 1, the pressure rise rate in negative pressure leak detection is more than 10Pa/min, and other conditions are the same as example 1.
The magnetic property of the final product was measured by a PFM pulsed magnetic field magnetometer with Br 12.97KGs, Hcj 19.5KOe and Hk/Hcj 95.2%. And detecting the blank carbon content and the nitrogen content of the obtained product by using an oxygen nitrogen hydrogen analyzer, wherein the carbon content is 790 mu g/g, and the nitrogen content is 578 mu g/g.
Comparative example 4
The vacuum degree in step 5 of example 1 was controlled to > 1Pa, and the other conditions were the same as in example 1.
The magnetic property of the final product was measured by a PFM pulsed magnetic field magnetometer with Br 13.01KGs, Hcj 20.6KOe and Hk/Hcj 97.7%. And detecting the carbon content and the nitrogen content of the blank of the obtained product by using an oxygen nitrogen hydrogen analyzer, wherein the carbon content is 730 mu g/g, and the nitrogen content is 450 mu g/g.
Comparative example 5
In step 3 of example 1, the hydrogen gas is replaced by CO (a gas which is easy to react and combine with the RE-Fe-B permanent magnet material at high temperature), namely the gas flow mill circulating process gas is replaced by a mixed gas of CO and nitrogen, and the rest steps are not changed.
And detecting the blank nitrogen content of the obtained product by using an oxygen nitrogen hydrogen analyzer, wherein the nitrogen content is 389 mu g/g.

Claims (10)

1. A method for preparing a low-nitrogen RE-Fe-B series permanent magnet material is characterized by comprising the steps of vacuum rapid hardening of raw materials for preparing the RE-Fe-B series permanent magnet material, hydrogen crushing, jet milling, profiling and sintering,
the jet mill is carried out by using a mixed gas of nitrogen and hydrogen or a mixed gas of nitrogen and oxygen, wherein the volume of the hydrogen accounts for 0.01-2% of the volume of the mixed gas of the nitrogen and the hydrogen, and the mass of the oxygen accounts for 0.01-0.2% of the mass of the mixed gas of the nitrogen and the oxygen.
2. The production method according to claim 1, wherein the raw materials for producing the RE-Fe-B system permanent magnetic material include rare earth elements, Fe and B;
preferably:
the rare earth elements comprise one or more of La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Y and mixed rare earth, such as PrNd; and/or the raw materials for preparing the RE-Fe-B series permanent magnet material also comprise Al, Cu, Co, Ga, Nb, Ti, Mo, V and/or Zr;
more preferably:
the RE-Fe-B series permanent magnet material is prepared from 31% of PrNd, 0.6% of Dy, 0.8% of Ho, 0.98% of B, 0.5% of Al, 0.2% of Cu, 0.13% of Ga, 0.2% of Nb and the balance of Fe by mass percent.
3. The method of claim 1, wherein the step of vacuum rapid solidification comprises the step of melting the feedstock under vacuum conditions to produce rapidly solidified flakes;
preferably:
the vacuum degree under the vacuum condition is below 30 Pa; and/or the smelting is carried out in a smelting furnace; and/or, the smelting further comprises the steps of casting and cooling, preferably under argon; and/or the thickness of the quick-setting sheet is 0.2-0.4 mm.
4. The method of claim 1, wherein the hydrogen fragmentation comprises a step of hydrogen-absorbing fragmentation of the rapidly solidified sheet;
preferably:
the hydrogen absorption is to put the quick-setting sheet into a hydrogen crushing furnace for hydrogen absorption, the pressure rise rate of the hydrogen crushing furnace is preferably less than 10Pa/min, and the pressure of a reaction kettle in the hydrogen crushing furnace is preferably positive pressure; and/or the hydrogen content in the hydrogen broken powder obtained after the breaking is less than 1200 mu g/g, for example 815 mu g/g.
5. The production method according to claim 1, wherein the volume of the hydrogen gas is 0.15% of the volume of the mixed gas of the nitrogen gas and the hydrogen gas in the jet mill;
and/or the mass of the oxygen accounts for 0.025 percent of the mass of the mixed gas of the nitrogen and the oxygen;
and/or the particle size D50 of the fine powder obtained after the jet milling is 2-5 μm, for example 4.3 μm.
6. The method of claim 1, wherein the profiling is performed at an orienting magnetic field strength above 1.4T;
and/or, the profiling is performed using a sample forming press;
and/or the pressed compact obtained after pressing is subjected to isostatic pressing or non-isostatic pressing, wherein the pressure of the isostatic pressing is preferably 180 +/-20 MPa.
7. The method according to claim 1, wherein the sintering is performed under vacuum conditions, such as a vacuum degree of less than 1 Pa;
and/or the sintering temperature is 1050 +/-20 ℃.
8. The method of claim 7, further comprising the step of aging after said sintering;
preferably, the aging comprises primary aging and secondary aging, the temperature of the primary aging is preferably 910 +/-50 ℃, and the temperature of the secondary aging is preferably 530 +/-50 ℃.
9. The method of claim 1, comprising the steps of:
(1) vacuum rapid solidification: smelting raw materials for preparing RE-Fe-B series permanent magnet materials, wherein the smelting is vacuumizing, heating and drying the materials, vacuumizing to less than or equal to 30Pa, and then casting and cooling in an argon environment to obtain a quick-setting sheet with the thickness of 0.2-0.4 mm; the raw materials for preparing the RE-Fe-B series permanent magnetic material comprise 31% of PrNd, 0.6% of Dy, 0.8% of Ho, 0.98% of B, 0.5% of Al, 0.2% of Cu, 0.13% of Ga, 0.2% of Nb and the balance of Fe in percentage by mass;
(2) hydrogen crushing: carrying out negative pressure leak detection on the hydrogen crushing furnace, keeping the pressure rise rate of the hydrogen crushing furnace less than 10Pa/min, then carrying out a hydrogen crushing process, controlling the pressure of a reaction kettle in the hydrogen crushing furnace to be positive pressure, and controlling the hydrogen content of hydrogen crushed powder obtained after hydrogen crushing to be 815 mug/g;
(3) and (3) jet milling: the mixed gas of nitrogen and hydrogen is used as circulating process gas of the jet mill, the volume of the hydrogen accounts for 0.15 percent of the volume of the total mixed gas, the jet mill grinds the hydrogen into fine powder, and the granularity D50 of the fine powder is 4.3 mu m;
(4) profiling: pressing into a pressed compact by using a sampling forming press, wherein the oriented magnetic field intensity is more than 1.4T, and the pressed compact is pressed by isostatic pressing, and the pressure of the isostatic pressing is 180 MPa;
(5) sintering and aging: after sintering treatment, the sintering degassing section is finished, the vacuum degree is controlled to be less than 1Pa, the sintering temperature is 1050 ℃, and then primary aging 910 ℃ and secondary aging 530 ℃ are carried out;
or, the preparation method comprises the following steps:
(1) vacuum rapid solidification: smelting raw materials for preparing RE-Fe-B series permanent magnet materials, wherein the smelting is vacuumizing, heating and drying the materials, vacuumizing to less than or equal to 30Pa, and then casting and cooling in an argon environment to obtain a quick-setting sheet with the thickness of 0.2-0.4 mm; the raw materials for preparing the RE-Fe-B series permanent magnetic material comprise 31% of PrNd, 0.6% of Dy, 0.8% of Ho, 0.98% of B, 0.5% of Al, 0.2% of Cu, 0.13% of Ga, 0.2% of Nb and the balance of Fe in percentage by mass;
(2) hydrogen crushing: carrying out negative pressure leak detection on the hydrogen crushing furnace, keeping the pressure rise rate of the hydrogen crushing furnace less than 10Pa/min, then carrying out a hydrogen crushing process, controlling the pressure of a reaction kettle in the hydrogen crushing furnace to be positive pressure, and controlling the hydrogen content of hydrogen crushed powder obtained after hydrogen crushing to be 815 mug/g;
(3) and (3) jet milling: the mixed gas of nitrogen and oxygen is used as circulating process gas of the jet mill, the mass percentage of the oxygen in the total mixed gas is 0.025%, the jet mill grinds the hydrogen powder into fine powder, and the granularity D50 of the fine powder is 4.3 mu m;
(4) profiling: pressing into a pressed compact by using a sampling forming press, wherein the oriented magnetic field intensity is more than 1.4T, and the pressed compact is pressed by isostatic pressing, and the pressure of the isostatic pressing is 180 MPa;
(5) sintering and aging: after sintering treatment, the sintering degassing section is finished, the vacuum degree is controlled to be less than 1Pa, the sintering temperature is 1050 ℃, and then primary aging 910 ℃ and secondary aging 530 ℃ are carried out.
10. A product produced by the method of any one of claims 1 to 9.
CN202010610108.8A 2020-06-29 2020-06-29 Preparation method of low-nitrogen RE-Fe-B series permanent magnet material and product thereof Pending CN111653405A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010610108.8A CN111653405A (en) 2020-06-29 2020-06-29 Preparation method of low-nitrogen RE-Fe-B series permanent magnet material and product thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010610108.8A CN111653405A (en) 2020-06-29 2020-06-29 Preparation method of low-nitrogen RE-Fe-B series permanent magnet material and product thereof

Publications (1)

Publication Number Publication Date
CN111653405A true CN111653405A (en) 2020-09-11

Family

ID=72352459

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010610108.8A Pending CN111653405A (en) 2020-06-29 2020-06-29 Preparation method of low-nitrogen RE-Fe-B series permanent magnet material and product thereof

Country Status (1)

Country Link
CN (1) CN111653405A (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01198409A (en) * 1988-02-01 1989-08-10 Shin Etsu Chem Co Ltd Method for pulverizing rare earth group alloy
CN101051544A (en) * 2007-05-10 2007-10-10 浙江大学 Method for preparing high performance sintered neodymium-iron-boron air stream millby hydrogenation
CN101615462A (en) * 2009-05-26 2009-12-30 安徽大地熊新材料股份有限公司 The preparation method who contains trace nitrogen Re-Fe-B series permanent magnetic material
CN105513733A (en) * 2016-01-14 2016-04-20 赣州富尔特电子股份有限公司 Method for preparing sintered rare earth permanent magnetic material
CN111326304A (en) * 2020-02-29 2020-06-23 厦门钨业股份有限公司 Rare earth permanent magnetic material and preparation method and application thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01198409A (en) * 1988-02-01 1989-08-10 Shin Etsu Chem Co Ltd Method for pulverizing rare earth group alloy
CN101051544A (en) * 2007-05-10 2007-10-10 浙江大学 Method for preparing high performance sintered neodymium-iron-boron air stream millby hydrogenation
CN101615462A (en) * 2009-05-26 2009-12-30 安徽大地熊新材料股份有限公司 The preparation method who contains trace nitrogen Re-Fe-B series permanent magnetic material
CN105513733A (en) * 2016-01-14 2016-04-20 赣州富尔特电子股份有限公司 Method for preparing sintered rare earth permanent magnetic material
CN111326304A (en) * 2020-02-29 2020-06-23 厦门钨业股份有限公司 Rare earth permanent magnetic material and preparation method and application thereof

Similar Documents

Publication Publication Date Title
CN104064346B (en) A kind of neodymium iron boron magnetic body and preparation method thereof
CN105575577B (en) Sinter cerium-rich rare earth permanent-magnet material and preparation method thereof
JP7220331B2 (en) Neodymium-iron-boron magnet material, raw material composition, manufacturing method, and application
WO2021169886A1 (en) Neodymium-iron-boron magnet material, raw material composition, preparation method therefor and use thereof
KR102631761B1 (en) Neodymium iron boron magnetic material, raw material composition, manufacturing method and application
CN104575901A (en) Neodymium iron boron magnet added with terbium powder and preparation method thereof
EP3355319A1 (en) Corrosion-resistant sintered neodymium-iron-boron magnet rich in lanthanum and cerium, and manufacturing method
CN104575902A (en) Neodymium iron boron magnet added with cerium and preparation method thereof
CN104575903A (en) Neodymium iron boron magnet added with Dy powder and preparation method thereof
KR20220113506A (en) Neodymium iron boron magnetic material, raw material composition, manufacturing method and application
CN110957092A (en) R-T-B series magnet material, raw material composition, preparation method and application
CN110957089A (en) Preparation method of samarium cobalt permanent magnet material
US8157927B2 (en) Raw material alloy for R-T-B system sintered magnet, R-T-B system sintered magnet and production method thereof
CN112002510A (en) High-coercivity permanent magnet based on holmium-rich rare earth permanent magnet liquid phase alloy and preparation method thereof
JP2011014631A (en) R-t-b-based rare-earth permanent magnet, and motor, automobile, generator and wind turbine generator
CN106328331B (en) Sintered NdFeB magnet assistant alloy slab and preparation method thereof
US11569012B2 (en) Method for improving performance of sintered NdFeB magnets
US20210280344A1 (en) Method for preparing NdFeB magnet powder
CN103667920B (en) Preparation method of Nd-Fe-B rare earth permanent magnetic alloy
CN110993235B (en) High-iron low-copper samarium-cobalt permanent magnet material and preparation method thereof
CN113871120B (en) Mixed rare earth permanent magnet material and preparation method thereof
CN110033914A (en) Improve the coercitive method of Sintered NdFeB magnet
CN111653405A (en) Preparation method of low-nitrogen RE-Fe-B series permanent magnet material and product thereof
CN112992461B (en) R-T-B magnet and preparation method thereof
CN114914046A (en) Medium-high performance neodymium iron boron magnet and preparation method thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
WD01 Invention patent application deemed withdrawn after publication

Application publication date: 20200911

WD01 Invention patent application deemed withdrawn after publication