CN116652182A - Sintering material box and method for improving consistency of magnetic properties of rare earth permanent magnet material - Google Patents

Sintering material box and method for improving consistency of magnetic properties of rare earth permanent magnet material Download PDF

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Publication number
CN116652182A
CN116652182A CN202310960548.XA CN202310960548A CN116652182A CN 116652182 A CN116652182 A CN 116652182A CN 202310960548 A CN202310960548 A CN 202310960548A CN 116652182 A CN116652182 A CN 116652182A
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CN
China
Prior art keywords
groove
side plate
sintering
area
rare earth
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Pending
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CN202310960548.XA
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Chinese (zh)
Inventor
刘峰
王茹钰
郭锋
李井朋
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Baotou Yunsheng Strong Magnetic Material Co ltd
Ningbo Yunsheng Magnet Devices Technology Co Ltd
Ningbo Yunsheng Co Ltd
Original Assignee
Baotou Yunsheng Strong Magnetic Material Co ltd
Ningbo Yunsheng Magnet Devices Technology Co Ltd
Ningbo Yunsheng Co Ltd
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Application filed by Baotou Yunsheng Strong Magnetic Material Co ltd, Ningbo Yunsheng Magnet Devices Technology Co Ltd, Ningbo Yunsheng Co Ltd filed Critical Baotou Yunsheng Strong Magnetic Material Co ltd
Priority to CN202310960548.XA priority Critical patent/CN116652182A/en
Publication of CN116652182A publication Critical patent/CN116652182A/en
Pending legal-status Critical Current

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    • 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
    • B22F3/003—Apparatus, e.g. furnaces
    • 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
    • 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
    • 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
    • H01F1/0573—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 obtained by reduction or by hydrogen decrepitation or embrittlement
    • 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
    • H01F1/0576—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 pressed, e.g. hot working
    • 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
    • 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

Abstract

The invention discloses a sintering material box and a method for improving the consistency of magnetic properties of rare earth permanent magnetic materials, wherein the sintering material box comprises a rectangular box body with an opening at the upper end, wherein the rectangular box body is formed by arranging and sequentially connecting a front side plate, a rear side plate, a left side plate, a right side plate and a bottom plate according to the front-rear left-right lower directions, a rectangular material cavity is formed by enclosing the front side plate, the rear side plate, the left side plate, the right side plate and the bottom plate, a first concave groove which is downwards concave is formed in the middle of the upper end of the front side plate, a second concave groove which is downwards concave is formed in the middle of the upper end of the rear side plate, a third concave groove which is downwards concave is formed in the middle of the upper end of the left side plate, and a fourth concave groove which is downwards concave is formed in the middle of the upper end of the right side plate; the method has the advantages that the method has the sealing and exhausting functions, improves the consistency of residual magnetism and intrinsic coercivity of the rare earth permanent magnet material, and is low in manufacturing cost, simple in operation steps, low in production and operation difficulty, free of influencing the production efficiency of the sintered neodymium-iron-boron magnet, free of using liquid sealing and free of introducing other impurities.

Description

Sintering material box and method for improving consistency of magnetic properties of rare earth permanent magnet material
Technical Field
The invention relates to a technology for improving consistency of magnetic properties of rare earth permanent magnet materials, in particular to a sintering material box and a method for improving consistency of magnetic properties of rare earth permanent magnet materials.
Background
The sintered NdFeB magnet is used as a third-generation rare earth permanent magnet material and is widely applied to equipment in the high and new technical fields of new energy automobiles, intelligent manufacturing, medical treatment, aerospace and the like due to the excellent magnetic performance. The sintered neodymium-iron-boron magnets applied to the equipment in the high and new technical field are often small-size blocks with a large number and cut by a large blank, and the consistency of the magnetic properties of each sintered neodymium-iron-boron magnet is ensured in order to ensure stable equipment performance. In terms of the development of the current industry, the consistency of magnetic performance is not solved well, and the poor consistency of magnetic performance is actually expressed in the following steps: the magnetic properties of sintered NdFeB magnets of the same brand and different batches are large, or the magnetic properties of blanks at different positions in a furnace are not small in the same batch of the furnace. Moreover, the magnetic properties of the same sintered NdFeB magnet are different from each other in different positions. Therefore, improving the consistency of the performance of sintered NdFeB products is an urgent problem to be solved by enterprises producing sintered NdFeB magnets.
In the preparation process of the sintered NdFeB magnet, a blank of the sintered NdFeB magnet needs to be protected by a material box in the sintering furnace entering process, and if nitrogen in the material box has gas exchange with outside air in the furnace entering process, the nitrogen has high probability of oxidizing a product. However, if only the tightness of the material box is considered, the release and volatilization of the gas in the deflation stage in the heating process are not timely, the shrinkage degree of the product and the compactness degree of the product are affected, the size of the sintered blank is inconsistent, and the performance of the product is greatly reduced, so that the exhaust function of the material box is also important. Therefore, it is very important to research a material box and sintering method for sintering NdFeB to consider the sealing performance and the exhaust effect of the material box.
The Chinese patent publication No. CN114054753A discloses a material box for sintering neodymium iron boron and a sintering method, wherein the material box comprises a box body and a box cover, a circle of grooves are formed in the middle of the upper end of the peripheral side wall of the box body, and a plurality of air grooves are formed in the bottoms of the grooves; the lower end of the box cover is provided with a circle of flange with a shape matched with the groove, the thickness of the flange at the position right above the air groove is smaller than the distance between the inner wall and the outer wall of the air groove, a blank is required to be put into the box during sintering, sealing liquid with a low boiling point is poured into the groove, the liquid level is positioned above the upper end face of the air groove and the bottom of the groove, the flange is aligned with the groove to cover the box cover, and the box cover is put into the sintering furnace. The material box can give consideration to the tightness and the exhaust function, the dimensional shrinkage consistency of sintered billets after sintering is good, the dimensional deviation of single products is greatly reduced, the density of the products is uniform and consistent, and the consistency of the magnetic performance (remanence and intrinsic coercivity) of sintered NdFeB magnets can be improved. However, the operation steps are complex, the operation difficulty is high, the production efficiency is affected, the sealing liquid is easy to introduce impurities, and the manufacturing cost of the box body and the box cover is high.
Disclosure of Invention
One of the technical problems to be solved by the invention is to provide a sintering material box for improving the consistency of the magnetic performance of the rare earth permanent magnet material, wherein the sintering material box has the advantages of improving the consistency of the residual magnetism and the intrinsic coercivity of the rare earth permanent magnet material while taking the tightness and the exhaust function into consideration, along with low manufacturing cost, simple operation steps, reduction of the production operation difficulty, no influence on the production efficiency of the sintered neodymium-iron-boron magnet, no need of using liquid sealing and no introduction of other impurities.
The technical scheme adopted by the invention for solving one of the technical problems is as follows: the utility model provides an improve sintering magazine of tombarthite permanent magnet material magnetism performance uniformity, includes upper end open-ended rectangle box body, rectangle box body pass through preceding curb plate, posterior lateral plate, left side board, right side board and bottom plate and arrange and connect gradually the constitution according to the position under the front and back, posterior lateral plate left side board right side board and the bottom plate between enclose into the rectangle material chamber, the upper end middle part of preceding curb plate be provided with the first recess of undercut, the upper end middle part of posterior lateral plate be provided with the second recess of undercut, the upper end middle part of left side board be provided with the third recess of undercut, the upper end middle part of right side board be provided with the fourth recess of undercut.
The cross sections of the first groove, the second groove, the third groove and the fourth groove along the vertical direction are isosceles trapezoids, and the lower bottoms of the isosceles trapezoids are positioned above the upper bottoms of the first groove, the second groove, the third groove and the fourth groove. In this structure, when a plurality of sintering magazine of range upon range of, because sintering magazine is loaded with the weight after the product is heavier, the sintering magazine of upper strata can generally be shelved earlier at next layer sintering magazine top and forward promotion again, makes upper layer sintering magazine and next layer sintering magazine align the range upon range of from top to bottom, and first recess, second recess, third recess and fourth recess are isosceles trapezoid along the cross-section of vertical direction, can avoid the last layer sintering magazine to appear blocking in the promotion in-process, and the operation is more quick and handy.
The height of the cross sections of the first groove, the second groove, the third groove and the fourth groove along the vertical direction is not more than 5mm, the difference between the bottoms and the bottoms of the cross sections of the first groove, the second groove, the third groove and the fourth groove along the vertical direction is not more than 50mm, the area of the cross section of the first groove is 1% -3% of the area of the front side surface of the rectangular material cavity, the area of the cross section of the second groove is 1% -3% of the area of the rear side surface of the rectangular material cavity, the area of the cross section of the third groove is 1% -3% of the area of the left side surface of the rectangular material cavity, and the area of the cross section of the fourth groove is 1% -3% of the area of the right side surface of the rectangular material cavity.
The bottom of bottom plate be provided with first annular groove, first annular groove's degree of depth be less than first recess second recess third recess and fourth recess's degree of depth, when a plurality of sintering magazine stacks from top to bottom, the top embedding that is located anterior board, posterior lateral plate, left side board and the right side board of the sintering magazine of next floor is located in the first annular groove that the bottom of the sintering magazine of upper strata set up.
The sintering material box for improving the consistency of the magnetic properties of the rare earth permanent magnetic materials further comprises a cover plate, a second annular groove is formed in the bottom of the cover plate, the depth of the second annular groove is smaller than that of the first groove, the second groove, the third groove and the fourth groove, and when the cover plate is arranged above the front side plate, the rear side plate, the left side plate and the right side plate, the front side plate, the rear side plate, the left side plate and the top of the right side plate can be embedded into the second annular groove.
The length of the front side plate along the left-right direction is 250-500mm, the height of the rear side plate along the up-down direction is 30-80mm, the thickness of the rear side plate along the front-back direction is 5-12mm, the length of the rear side plate along the left-right direction is equal to the length of the front side plate along the left-right direction, the height of the rear side plate along the up-down direction is equal to the height of the front side plate along the up-down direction, and the thickness of the rear side plate along the front-back direction is equal to the thickness of the front side plate along the front-back direction; the length of the left side plate along the front-back direction is 250-500mm, the height of the left side plate along the up-down direction is 30-80mm, the thickness of the right side plate along the left-right direction is 5-12mm, the length of the right side plate along the front-back direction is equal to the length of the left side plate along the front-back direction, the height of the right side plate along the up-down direction is equal to the height of the left side plate along the up-down direction, and the thickness of the right side plate along the left-right direction is equal to the thickness of the left side plate along the left-right direction.
The front side plate, the rear side plate, the left side plate, the right side plate and the bottom plate are made of graphite or carbon fiber.
Compared with the prior art, the sintering material box has the advantages that the middle part of the upper end of the front side plate of the sintering material box is provided with the first concave groove which is concave downwards, the middle part of the upper end of the rear side plate is provided with the second concave groove which is concave downwards, the middle part of the upper end of the left side plate is provided with the third concave groove which is concave downwards, the middle part of the upper end of the right side plate is provided with the fourth concave groove which is concave downwards, so that the exhaust channel of blanks during sintering is effectively increased, impurity gas is exhausted from the first concave groove, the second concave groove, the third concave groove and the fourth concave groove in the stage of massive air release of the blanks, the exhaust efficiency and the uniformity of blank exhaust at different positions are improved, the carbon content of the blanks is reduced, the consistency of the carbon content of the blanks is also improved, the consistency of the residual magnetic intrinsic coercive force of rare earth permanent magnet materials of neodymium-iron-boron materials is improved, meanwhile, the bottom plate of the sintering material box is provided with the first annular groove, the cover plate of the sintering material box is provided with a second annular groove, the depths of the first annular groove and the second annular groove are smaller than the depths of the first groove, the second groove, the third groove and the fourth groove, when a plurality of sintering material boxes are stacked up and down and the cover plate is covered on the uppermost sintering material box, the tops of the front side plate, the rear side plate, the left side plate and the right side plate of the uppermost sintering material box are embedded into the second annular groove on the cover plate, and the tops of the front side plate, the rear side plate, the left side plate and the right side plate of the next sintering material box are embedded into the first annular groove arranged at the bottom plate of the sintering material box on the upper layer in other layers of sintering material boxes, so that the blank and air can be prevented from being directly contacted in a large area in the process of entering the sintering furnace, the sealing performance is considered, therefore, the sintering material box of the invention has both the sealing performance and the exhaust function, the consistency of the remanence and intrinsic coercivity of the rare earth permanent magnet material is improved, the manufacturing cost is low, the operation steps are simple, the production operation difficulty is reduced, the production efficiency of the sintered neodymium-iron-boron magnet is not affected, liquid sealing is not needed, and other impurities are not introduced. The second technical problem to be solved by the invention is to provide a method for improving the consistency of the magnetic properties of rare earth permanent magnetic materials. According to the method, the sintering process is adjusted, so that the degassing temperature of the degassing agent is changed from the original fixed temperature to the fluctuation temperature, the degassing process of the neodymium-iron-boron blank is increased, the degassing effect is further improved, impurities are effectively removed, the consistency of the residual magnetism and the intrinsic coercivity of the rare earth permanent magnet material is further improved, meanwhile, the sintering material box is improved, the tightness and the degassing function are both considered, the consistency of the residual magnetism and the intrinsic coercivity of the rare earth permanent magnet material is improved, meanwhile, the manufacturing cost is low, the operation steps are simple, the production operation difficulty is reduced, the production efficiency of the sintered neodymium-iron-boron magnet is not affected, and the impurities are not introduced.
The second technical scheme adopted for solving the technical problems is as follows: a method for improving consistency of magnetic properties of rare earth permanent magnet materials comprises the following steps:
(1) Preparing a material according to a formula of the rare earth permanent magnet material, and obtaining a cast sheet through a rapid hardening and sheet throwing technology;
(2) Hydrogen crushing the cast sheet to obtain alloy coarse powder, and then filling the alloy coarse powder into a tank body protected by inert gas for preservation;
(3) Transferring the alloy coarse powder into an air flow grinding device for grinding to obtain fine powder with the granularity D50 of 4.0-4.5 mu m, and then filling the fine powder into a tank body protected by inert gas, wherein oxygen supplementing is carried out according to the process requirements during the grinding process of the air flow grinding device, and the online oxygen content of the air flow grinding device is kept between 0 and 50 ppm;
(4) Transferring the fine powder to a forming workshop, performing compression forming on the fine powder through a press to obtain a blank, packaging the blank with a vacuum packaging bag, and packaging with a vacuum packaging machine, wherein inert gas is always filled into the press in the compression forming process, and the oxygen content is always lower than 0.02%;
(5) The packaged blank is sent into a sintering film stripping glove box after being subjected to water isostatic pressing treatment, and the oxygen content in the sintering film stripping glove box is reduced to below 0.02 percent;
(6) In a sintering film stripping glove box, film stripping treatment is carried out on blanks, the blanks are taken out from a vacuum packaging bag and then are arranged in a sintering material box which is placed in the sintering film stripping glove box in advance, the sintering material box comprises a rectangular box body with an opening at the upper end, the rectangular box body is formed by splicing a front side plate, a rear side plate, a left side plate, a right side plate and a bottom plate according to the directions of front, rear, left and right sides, rectangular material cavities for arranging the blanks are formed between the front side plate, the rear side plate, the right side plate and the bottom plate in a surrounding manner, a first concave groove which is downwards concave is formed in the middle of the upper end of the front side plate, a second concave groove which is downwards concave is formed in the middle of the upper end of the rear side plate, a third concave groove which is downwards concave is formed in the middle of the upper end of the left side plate, and a fourth concave groove which is downwards concave is formed in the middle of the upper end of the right side plate;
(7) Under the protection of nitrogen, stacking the sintering material boxes filled with blanks up and down according to the furnace loading amount, covering a cover plate on the uppermost sintering material box, and then orderly arranging the stacked sintering material boxes in a furnace chamber of a sintering furnace for high-temperature sintering in a furnace back feeding mode, wherein the high-temperature sintering process adopts a vibration sintering process, and the specific process is as follows: heating for 20min-50min to 330-430 ℃, then repeating the cooling and heating process for 2-5 times, then continuously heating for 60min-120min to 540-650 ℃ and preserving heat for 1h-3h, then heating for 60min-120min to 780-900 ℃ and preserving heat for 1h-3h, continuously heating for 20min-50min to 900-980 ℃ and preserving heat for 1h-3h, then continuously heating for 30min-60min to 1000-1100 ℃ and preserving heat for 3h-8h, finally performing subsequent aging treatment, and discharging after the aging treatment is finished to obtain a sintered neodymium iron boron magnet, namely a rare earth permanent magnet material, wherein the cooling and heating process each time is as follows: firstly cooling for 20min-50min, wherein the cooling amplitude is 40-80 ℃, and then heating for 20min-50min to 330-430 ℃.
The cross sections of the first groove, the second groove, the third groove and the fourth groove along the vertical direction are isosceles trapezoids, and the lower bottoms of the isosceles trapezoids are positioned above the upper bottoms of the first groove, the second groove, the third groove and the fourth groove. The height of the cross sections of the first groove, the second groove, the third groove and the fourth groove along the vertical direction is not more than 5mm, the difference between the bottoms and the bottoms of the cross sections of the first groove, the second groove, the third groove and the fourth groove along the vertical direction is not more than 50mm, the area of the cross section of the first groove is 1% -3% of the area of the front side surface of the rectangular material cavity, the area of the cross section of the second groove is 1% -3% of the area of the rear side surface of the rectangular material cavity, the area of the cross section of the third groove is 1% -3% of the area of the left side surface of the rectangular material cavity, and the area of the cross section of the fourth groove is 1% -3% of the area of the right side surface of the rectangular material cavity.
Compared with the prior patent, the method has the advantages that the middle part of the upper end of the front side plate of the sintering material box is provided with the first concave groove which is downward, the middle part of the upper end of the rear side plate is provided with the second concave groove which is downward, the middle part of the upper end of the left side plate is provided with the third concave groove which is downward, the middle part of the upper end of the right side plate is provided with the fourth concave groove which is downward, thus effectively increasing the exhaust passage of blanks during sintering, and in the stage of discharging a large amount of blanks, impurity gas is discharged from the first concave groove, the second concave groove, the third concave groove and the fourth concave groove, improving the exhaust efficiency and the uniformity of blank exhaust at different positions, reducing the carbon content of the blanks, improving the uniformity of the carbon content of the blanks, and improving the uniformity of the residual magnetic intrinsic coercivity of the rare earth permanent magnet material of the neodymium-iron-boron material, meanwhile, the bottom plate of the sintering material box is provided with a first annular groove, the cover plate of the sintering material box is provided with a second annular groove, the depths of the first annular groove and the second annular groove are smaller than those of the first groove, the second groove, the third groove and the fourth groove, when a plurality of sintering material boxes are stacked up and down and the cover plate is covered on the uppermost sintering material box, the tops of the front side plate, the rear side plate, the left side plate and the right side plate of the uppermost sintering material box are embedded into the second annular groove on the cover plate, the tops of the front side plate, the rear side plate, the left side plate and the right side plate of the sintering material box on the next layer are embedded into the first annular groove arranged at the bottom plate of the sintering material box on the previous layer, so that the blanks can be prevented from directly contacting with air in a large area in the process of entering a sintering furnace, and tightness is considered, during sintering, the stacked sintering material boxes adopt a mode of feeding the sintering material boxes into a furnace after the furnace (the mode of feeding the sintering material boxes into the furnace after the furnace refers to that a film stripping glove box is connected with a sintering furnace back door, the sintering furnace back door is opened, the stacked sintering material boxes in the film stripping glove box are transferred into the sintering furnace under the protection of nitrogen), and the stacked sintering material boxes are arranged in sequence in the furnace chamber of the sintering furnace to perform high-temperature sintering, so that blanks are prevented from contacting air and oxidization of the blanks is prevented; in addition, the sintered NdFeB magnet is added with an antioxidant, a lubricant and other additives which ensure that powder is not oxidized and help the powder to be ground by air flow grinding, the additives such as the lubricant, a release agent and the like are also used for improving the powder formability in the stirring and forming stages, the orientation degree of powder particles in a magnetic field is improved, the types of the existing additives are various, the use of the powder modification additive can improve the performance of the sintered NdFeB magnet, so that the addition amount of the powder modification additive in the industry is gradually increased, but the additives are a multi-component organic compound, a large amount of C elements and O elements are introduced, and the performance of the NdFeB permanent magnet material is affected if the excessive C elements and O elements are not discharged in time, so the invention further improves the sintering process into an oscillation sintering process, and the invention comprises the following steps of: heating for 20min-50min to 330-430 ℃, then repeating the cooling and heating process for 2-5 times, then continuously heating for 60min-120min to 540-650 ℃ and preserving heat for 1h-3h, then heating for 60min-120min to 780-900 ℃ and preserving heat for 1h-3h, continuously heating for 20min-50min to 900-980 ℃ and preserving heat for 1h-3h, then continuously heating for 30min-60min to 1000-1100 ℃ and preserving heat for 3h-8h, finally performing subsequent aging treatment, and discharging after the aging treatment is finished to obtain a sintered neodymium iron boron magnet, namely a rare earth permanent magnet material, wherein the cooling and heating process each time is as follows: the temperature is reduced for 20min-50min, wherein the temperature reduction range is 40-80 ℃, the temperature is increased for 20min-50min to 330-430 ℃, C and O are discharged through alternation of temperature increase and temperature reduction in the vibration sintering process (wherein the temperature stage of 330-430 ℃ is the optimal temperature range for C and O discharge), so that the invention changes the degassing temperature of the degassing agent from the original fixed temperature to the fluctuating temperature through adjusting the sintering process, increases the degassing process of the neodymium-iron-boron green compact, further improves the degassing effect, effectively removes impurities, improves the consistency of residual magnetism and intrinsic coercivity of the rare earth permanent magnet material, combines the improved sintering material box, ensures that the manufacturing cost is low while the consistency of residual magnetism and intrinsic coercivity of the rare earth permanent magnet material is improved, has simple operation steps, reduces the production operation difficulty, does not influence the production efficiency of the sintered neodymium-iron-boron magnet, and does not introduce impurities.
Drawings
FIG. 1 is a schematic diagram of a sintering material box for improving consistency of magnetic properties of rare earth permanent magnet materials;
FIG. 2 is a schematic diagram II of a sintering material box for improving the consistency of magnetic properties of rare earth permanent magnet materials;
FIG. 3 is a front view of a sintering magazine for improving consistency of magnetic properties of rare earth permanent magnet materials according to the present invention;
FIG. 4 is a left side view of the sintering material box for improving the consistency of the magnetic properties of the rare earth permanent magnet material;
fig. 5 is a top view of the sintering material box for improving the consistency of the magnetic properties of the rare earth permanent magnet material.
Detailed Description
The invention discloses a sintering material box for improving consistency of magnetic properties of rare earth permanent magnet materials, and the sintering material box is further described in detail below with reference to the embodiment of the drawings.
Embodiment one: as shown in fig. 1 to 5, a sintering magazine for improving the consistency of magnetic properties of rare earth permanent magnet materials comprises a rectangular box body with an opening at the upper end, wherein the rectangular box body is formed by arranging and sequentially connecting a front side plate 1, a rear side plate 2, a left side plate 3, a right side plate 4 and a bottom plate 5 according to the front-back left-right lower directions, a rectangular material cavity 6 is formed by encircling between the front side plate 1, the rear side plate 2, the left side plate 3, the right side plate 4 and the bottom plate 5, a first concave groove 7 which is concave downwards is arranged in the middle of the upper end of the front side plate 1, a second concave groove 8 which is concave downwards is arranged in the middle of the upper end of the rear side plate 2, a third concave groove 9 which is concave downwards is arranged in the middle of the upper end of the left side plate 3, and a fourth concave downwards is arranged in the middle of the upper end of the right side plate 4.
In this embodiment, the front side plate 1, the rear side plate 2, the left side plate 3, the right side plate 4 and the bottom plate 5 are made of graphite.
Embodiment two: this embodiment is substantially the same as embodiment one, except that: in this embodiment, the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 along the vertical direction are isosceles trapezoids, and the lower bottoms of the isosceles trapezoids are located above the upper bottoms thereof.
In this embodiment, the heights of the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 along the vertical direction are 3mm, the difference between the bottoms and the bottoms of the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 along the vertical direction is 50mm, the area of the cross section of the first groove 7 is 1% of the front side surface area of the rectangular material cavity 6, the area of the cross section of the second groove 8 is 1% of the rear side surface area of the rectangular material cavity 6, the area of the cross section of the third groove 9 is 1% of the left side surface area of the rectangular material cavity 6, and the area of the cross section of the fourth groove 10 is 1% of the right side surface area of the rectangular material cavity 6.
In this embodiment, the bottom of the bottom plate 5 is provided with a first annular groove 11, the depth of the first annular groove 11 is smaller than the depths of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10, and when a plurality of sintering cartridges are stacked up and down, the top of the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4 of the sintering cartridge located in the next layer is embedded into the first annular groove 11 provided at the bottom of the sintering cartridge located in the previous layer.
In this embodiment, a sintering magazine for improving consistency of magnetic properties of rare earth permanent magnetic materials further includes a cover plate 12, a second annular groove 13 is provided at the bottom of the cover plate 12, the depth of the second annular groove 13 is smaller than the depth of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10, and when the cover plate 12 is disposed above the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4, the top of the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4 can be embedded into the second annular groove 13, and the cover plate 12 is made of graphite.
In the present embodiment, the length of the front side plate 1 in the left-right direction is 500mm, the height in the up-down direction is 80mm, the thickness in the front-back direction is 5mm, the length of the rear side plate 2 in the left-right direction is equal to the length of the front side plate 1 in the left-right direction, the height of the rear side plate 2 in the up-down direction is equal to the height of the front side plate 1 in the up-down direction, and the thickness of the rear side plate 2 in the front-back direction is equal to the thickness of the front side plate 1 in the front-back direction; the length of the left side plate 3 in the front-rear direction is 300mm, the height in the up-down direction is 80mm, the thickness in the left-right direction is 5mm, the length of the right side plate 4 in the front-rear direction is equal to the length of the left side plate 3 in the front-rear direction, the height of the right side plate 4 in the up-down direction is equal to the height of the left side plate 3 in the up-down direction, and the thickness of the right side plate 4 in the left-right direction is equal to the thickness of the left side plate 3 in the left-right direction.
Embodiment III: this embodiment is substantially the same as embodiment one, except that: in this embodiment, the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 along the vertical direction are isosceles trapezoids, and the lower bottoms of the isosceles trapezoids are located above the upper bottoms thereof.
In this embodiment, the height of the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 in the vertical direction is 5mm, the difference between the bottom and the upper bottom of the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 in the vertical direction is 50mm, the area of the cross section of the first groove 7 is 3% of the front side area of the rectangular material cavity 6, the area of the cross section of the second groove 8 is 3% of the rear side area of the rectangular material cavity 6, the area of the cross section of the third groove 9 is 3% of the left side area of the rectangular material cavity 6, and the area of the cross section of the fourth groove 10 is 3% of the right side area of the rectangular material cavity 6.
In this embodiment, the bottom of the bottom plate 5 is provided with a first annular groove 11, the depth of the first annular groove 11 is smaller than the depths of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10, and when a plurality of sintering cartridges are stacked up and down, the top of the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4 of the sintering cartridge located in the next layer is embedded into the first annular groove 11 provided at the bottom of the sintering cartridge located in the previous layer.
In this embodiment, a sintering magazine for improving consistency of magnetic properties of rare earth permanent magnetic materials further includes a cover plate 12, a second annular groove 13 is provided at the bottom of the cover plate 12, the depth of the second annular groove 13 is smaller than the depth of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10, and when the cover plate 12 is disposed above the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4, the top of the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4 can be embedded into the second annular groove 13, and the cover plate 12 is made of graphite.
In the present embodiment, the length of the front side plate 1 in the left-right direction is 500mm, the height in the up-down direction is 80mm, the thickness in the front-back direction is 5mm, the length of the rear side plate 2 in the left-right direction is equal to the length of the front side plate 1 in the left-right direction, the height of the rear side plate 2 in the up-down direction is equal to the height of the front side plate 1 in the up-down direction, and the thickness of the rear side plate 2 in the front-back direction is equal to the thickness of the front side plate 1 in the front-back direction; the length of the left side plate 3 in the front-rear direction is 300mm, the height in the up-down direction is 80mm, the thickness in the left-right direction is 5mm, the length of the right side plate 4 in the front-rear direction is equal to the length of the left side plate 3 in the front-rear direction, the height of the right side plate 4 in the up-down direction is equal to the height of the left side plate 3 in the up-down direction, and the thickness of the right side plate 4 in the left-right direction is equal to the thickness of the left side plate 3 in the left-right direction.
The invention also discloses a method for improving the consistency of the magnetic properties of the rare earth permanent magnet material, and the method is further described in detail below with reference to the embodiment of the drawings.
Embodiment four: a method for improving consistency of magnetic properties of rare earth permanent magnet materials comprises the following steps:
(1) Preparing materials according to the formula of a 42SH brand neodymium-iron-boron magnet, and obtaining cast sheets through a rapid hardening and sheet throwing technology;
(2) Hydrogen crushing the cast sheet to obtain alloy coarse powder, and then filling the alloy coarse powder into a tank body protected by inert gas for preservation;
(3) Transferring the alloy coarse powder into an air flow grinding device for grinding to obtain fine powder with the granularity D50 of 4.0-4.5 mu m, and then filling the fine powder into a tank body protected by inert gas, wherein oxygen supplementing is carried out according to the process requirements during the grinding process of the air flow grinding device, and the online oxygen content of the air flow grinding device is kept between 0 and 50 ppm;
(4) Transferring the fine powder to a forming workshop, performing compression forming on the fine powder through a press to obtain a blank, packaging the blank with a vacuum packaging bag, and packaging with a vacuum packaging machine, wherein inert gas is always filled into the press in the compression forming process, and the oxygen content is always lower than 0.02%;
(5) The packaged blank is sent into a sintering film stripping glove box after being subjected to water isostatic pressing treatment, and the oxygen content in the sintering film stripping glove box is reduced to below 0.02 percent;
(6) In a sintering film peeling glove box, film peeling treatment is carried out on blanks, the blanks are taken out from a vacuum packaging bag and then are arranged in a sintering material box which is placed in the sintering film peeling glove box in advance, as shown in fig. 1 to 5, the sintering material box comprises a rectangular box body with an opening at the upper end, the rectangular box body is formed by splicing a front side plate 1, a rear side plate 2, a left side plate 3, a right side plate 4 and a bottom plate 5 according to the directions of front, rear, left and right sides, the front side plate 1, the rear side plate 2, the left side plate 3, the right side plate 4 and the bottom plate 5, a rectangular material cavity 6 for arranging the blanks is enclosed between the front side plate 1, the rear side plate 2, the left side plate 3, the right side plate 4 and the bottom plate 5, a first concave groove 7 which is downwards concave is arranged at the middle part of the upper end of the front side plate 1, a second concave groove 8 which is downwards concave is arranged at the middle part of the upper end of the rear side plate 2, a third concave groove 9 which is downwards concave is arranged at the middle part of the upper end of the left side plate 3, and a fourth concave groove 10 which is downwards concave is arranged at the middle part of the upper end of the right side plate 4; the front side plate 1, the rear side plate 2, the left side plate 3, the right side plate 4 and the bottom plate 5 are made of graphite;
(7) Under the protection of nitrogen, stacking the sintering material boxes filled with blanks up and down according to the furnace loading amount, covering a cover plate 12 on the uppermost sintering material box, wherein the cover plate 12 is made of graphite, and then arranging the stacked sintering material boxes in a furnace chamber of a sintering furnace in sequence by adopting a furnace-after-furnace feeding mode for high-temperature sintering, wherein the high-temperature sintering process adopts a vibration sintering process, and the specific process is as follows: heating for 30min to 430 ℃, repeating the cooling and heating process for 3 times, continuously heating for 90min to 600 ℃ and preserving heat for 1h, heating for 90min to 850 ℃ and preserving heat for 1h, continuously heating for 40min to 960 ℃ and preserving heat for 1.5h, then heating for 30min to 1060 ℃ and preserving heat for 4h, finally performing subsequent aging treatment, and discharging after the aging treatment is finished to obtain a sintered neodymium-iron-boron magnet, namely a rare earth permanent magnet material, wherein the cooling and heating process for each time is as follows: firstly cooling for 30min to 350 ℃, and then heating for 30min to 430 ℃.
In this embodiment, the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 along the vertical direction are isosceles trapezoids, and the lower bottoms of the isosceles trapezoids are located above the upper bottoms thereof.
In this embodiment, the height of the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 in the vertical direction is 3mm, the difference between the bottom and the upper bottom of the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 in the vertical direction is 50mm, the area of the cross section of the first groove 7 is 1% of the front side area of the rectangular cavity 6, the area of the cross section of the second groove 8 is 1% of the rear side area of the rectangular cavity 6, the area of the cross section of the third groove 9 is 1% of the left side area of the rectangular cavity 6, and the area of the cross section of the fourth groove 10 is 1% of the right side area of the rectangular cavity 6.
In this embodiment, the bottom of the bottom plate 5 is provided with a first annular groove 11, the depth of the first annular groove 11 is smaller than the depths of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10, and when a plurality of sintering cartridges are stacked up and down, the top of the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4 of the sintering cartridge located in the next layer is embedded into the first annular groove 11 provided at the bottom of the sintering cartridge located in the previous layer.
In this embodiment, the bottom of the cover plate 12 is provided with the second annular groove 13, the depth of the second annular groove 13 is smaller than the depths of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10, and when the cover plate 12 is disposed above the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4, the tops of the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4 can be embedded into the second annular groove 13.
In the present embodiment, the length of the front side plate 1 in the left-right direction is 500mm, the height in the up-down direction is 80mm, the thickness in the front-back direction is 5mm, the length of the rear side plate 2 in the left-right direction is equal to the length of the front side plate 1 in the left-right direction, the height of the rear side plate 2 in the up-down direction is equal to the height of the front side plate 1 in the up-down direction, and the thickness of the rear side plate 2 in the front-back direction is equal to the thickness of the front side plate 1 in the front-back direction; the length of the left side plate 3 in the front-rear direction is 300mm, the height in the up-down direction is 80mm, the thickness in the left-right direction is 5mm, the length of the right side plate 4 in the front-rear direction is equal to the length of the left side plate 3 in the front-rear direction, the height of the right side plate 4 in the up-down direction is equal to the height of the left side plate 3 in the up-down direction, and the thickness of the right side plate 4 in the left-right direction is equal to the thickness of the left side plate 3 in the left-right direction.
In this embodiment, during the high temperature sintering process, various impurity gases in the blank can be more rapidly and uniformly discharged through the first groove 7, the second groove 8, the third groove 9, and the fourth groove 10 in the sintering magazine. 8 sintered NdFeB magnets were selected at random positions after being discharged from the furnace and used as samples for testing magnetic properties and carbon content, and specific data are shown in Table 1.
Comparative example one: the present comparative example uses a conventional sintering process, and the sintering cartridge of example four is not used, but a conventional cartridge is used, and the other processes are the same as example four. 8 sintered NdFeB magnets of comparative example I were selected at random positions after tapping and used as samples for testing magnetic properties and carbon content, and specific data are shown in Table 2.
Table 1: example four sample magnetic Properties
Table 2: comparative example one sample magnetic Properties
As can be seen from an analysis of the data in tables 1 and 2: example four samples had a maximum remanence of 13.39 kg Gs, a minimum remanence of 13.31 kg Gs, and a difference (deltaB r ) Is 0.08 kGs, intrinsic coercivityH cJ The maximum value is 20.60 kOe,H cJ minimum 20.24 kOe, difference (deltaH cJ ) 0.36kOe. Comparative example A sample had a maximum remanence of 13.37 kGs, a minimum remanence of 13.12 kGs, and a difference (. DELTA.B r ) Is 0.25kGs, intrinsic coercivity H cJ The maximum value is 20.54 kOe,H cJ minimum 19.82kOe, difference (deltaH cJ ) 0.72kOe. Therefore, the blank in the fourth embodiment has improved remanence and coercivity consistency, lower carbon content,the consistency of the carbon content is obviously improved, and the consistency of the magnetic performance of the sintered NdFeB magnet is generally improved.
Fifth embodiment: a method for improving consistency of magnetic properties of rare earth permanent magnet materials comprises the following steps:
(1) Preparing materials according to the formula of a 45SH brand neodymium-iron-boron magnet, and obtaining cast sheets through a rapid hardening and sheet throwing technology;
(2) Hydrogen crushing the cast sheet to obtain alloy coarse powder, and then filling the alloy coarse powder into a tank body protected by inert gas for preservation;
(3) Transferring the alloy coarse powder into an air flow grinding device for grinding to obtain fine powder with the granularity D50 of 4.0-4.5 mu m, and then filling the fine powder into a tank body protected by inert gas, wherein oxygen supplementing is carried out according to the process requirements during the grinding process of the air flow grinding device, and the online oxygen content of the air flow grinding device is kept between 0 and 50 ppm;
(4) Transferring the fine powder to a forming workshop, performing compression forming on the fine powder through a press to obtain a blank, packaging the blank with a vacuum packaging bag, and packaging with a vacuum packaging machine, wherein inert gas is always filled into the press in the compression forming process, and the oxygen content is always lower than 0.02%;
(5) The packaged blank is sent into a sintering film stripping glove box after being subjected to water isostatic pressing treatment, and the oxygen content in the sintering film stripping glove box is reduced to below 0.02 percent;
(6) In a sintering film peeling glove box, film peeling treatment is carried out on blanks, the blanks are taken out from a vacuum packaging bag and then are arranged in a sintering material box which is placed in the sintering film peeling glove box in advance, as shown in fig. 1 to 5, the sintering material box comprises a rectangular box body with an opening at the upper end, the rectangular box body is formed by splicing a front side plate 1, a rear side plate 2, a left side plate 3, a right side plate 4 and a bottom plate 5 according to the directions of front, rear, left and right sides, the front side plate 1, the rear side plate 2, the left side plate 3, the right side plate 4 and the bottom plate 5, a rectangular material cavity 6 for arranging the blanks is enclosed between the front side plate 1, the rear side plate 2, the left side plate 3, the right side plate 4 and the bottom plate 5, a first concave groove 7 which is downwards concave is arranged at the middle part of the upper end of the front side plate 1, a second concave groove 8 which is downwards concave is arranged at the middle part of the upper end of the rear side plate 2, a third concave groove 9 which is downwards concave is arranged at the middle part of the upper end of the left side plate 3, and a fourth concave groove 10 which is downwards concave is arranged at the middle part of the upper end of the right side plate 4;
(7) Under the protection of nitrogen, stacking the sintering material boxes filled with blanks up and down according to the furnace loading amount, covering a cover plate 12 on the uppermost sintering material box, wherein the cover plate 12 is made of graphite, and then arranging the stacked sintering material boxes in a furnace chamber of a sintering furnace in sequence by adopting a furnace-after-furnace feeding mode for high-temperature sintering, wherein the high-temperature sintering process adopts a vibration sintering process, and the specific process is as follows: heating for 30min to 430 ℃, repeating the cooling and heating process for 3 times, continuously heating for 90min to 600 ℃ and preserving heat for 1h, heating for 90min to 850 ℃ and preserving heat for 2h, continuously heating for 40min to 960 ℃ and preserving heat for 1.5h, then heating for 30min to 1060 ℃ and preserving heat for 4h, finally performing subsequent aging treatment, and discharging after the aging treatment is finished to obtain a sintered neodymium-iron-boron magnet, namely a rare earth permanent magnet material, wherein the cooling and heating process for each time is as follows: firstly cooling for 30min to 350 ℃, and then heating for 30min to 430 ℃.
In this embodiment, the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 along the vertical direction are isosceles trapezoids, and the lower bottoms of the isosceles trapezoids are located above the upper bottoms thereof.
In this embodiment, the height of the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 in the vertical direction is 3mm, the difference between the bottom and the upper bottom of the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 in the vertical direction is 50mm, the area of the cross section of the first groove 7 is 1% of the front side area of the rectangular cavity 6, the area of the cross section of the second groove 8 is 1% of the rear side area of the rectangular cavity 6, the area of the cross section of the third groove 9 is 1% of the left side area of the rectangular cavity 6, and the area of the cross section of the fourth groove 10 is 1% of the right side area of the rectangular cavity 6.
In this embodiment, the bottom of the bottom plate 5 is provided with a first annular groove 11, the depth of the first annular groove 11 is smaller than the depths of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10, and when a plurality of sintering cartridges are stacked up and down, the top of the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4 of the sintering cartridge located in the next layer is embedded into the first annular groove 11 provided at the bottom of the sintering cartridge located in the previous layer.
In this embodiment, the bottom of the cover plate 12 is provided with the second annular groove 13, the depth of the second annular groove 13 is smaller than the depths of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10, and when the cover plate 12 is disposed above the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4, the tops of the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4 can be embedded into the second annular groove 13.
In the present embodiment, the length of the front side plate 1 in the left-right direction is 500mm, the height in the up-down direction is 80mm, the thickness in the front-back direction is 5mm, the length of the rear side plate 2 in the left-right direction is equal to the length of the front side plate 1 in the left-right direction, the height of the rear side plate 2 in the up-down direction is equal to the height of the front side plate 1 in the up-down direction, and the thickness of the rear side plate 2 in the front-back direction is equal to the thickness of the front side plate 1 in the front-back direction; the length of the left side plate 3 in the front-rear direction is 300mm, the height in the up-down direction is 80mm, the thickness in the left-right direction is 5mm, the length of the right side plate 4 in the front-rear direction is equal to the length of the left side plate 3 in the front-rear direction, the height of the right side plate 4 in the up-down direction is equal to the height of the left side plate 3 in the up-down direction, and the thickness of the right side plate 4 in the left-right direction is equal to the thickness of the left side plate 3 in the left-right direction.
In this embodiment, during the high temperature sintering process, various impurity gases in the blank can be more rapidly and uniformly discharged through the first groove 7, the second groove 8, the third groove 9, and the fourth groove 10 in the sintering magazine. 8 sintered NdFeB magnets were selected at random positions after being discharged from the furnace and used as samples for testing magnetic properties and carbon content, and specific data are shown in Table 3.
Comparative example two: the sintering magazine of example five was used in this comparative example, but a conventional sintering process was employed. 8 sintered NdFeB magnets of comparative example II were selected at random positions after being discharged from the furnace and used as samples for testing magnetic properties and carbon content, and specific data are shown in Table 4.
Table 3: example five sample magnetic Properties
Table 4: comparative example two sample magnetic Properties
From an analysis of the data in tables 3 and 4, it can be seen that the sample of example five had a maximum remanence of 13.65kGs and a minimum remanence of 13.51kGs, and the difference (ΔB r ) Is 0.14 and kGs. Intrinsic coercivityH cJ The maximum value is 21.95kOe,H cJ the minimum value was 21.62kOe, the difference (. DELTA.H cJ ) 0.33kOe. The sample of comparative example II had a maximum remanence of 13.61kGs, a minimum remanence of 13.40kGs, and a difference (deltaB r ) 0.21 and kGs. Intrinsic coercivityH cJ The maximum value is 22.27kOe,H cJ a minimum value of 21.39kOe, a difference (ΔH cJ ) At 0.88kOe, and at this time the oxygen content of the sample generally increased, the sample was easily oxidized, resulting in a decrease in magnetic properties. Therefore, the sintering process is combined with the proper range of the heights of the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 along the vertical direction, so that the consistency of the residual magnetism and the coercive force of the sintered NdFeB magnet can be improved, the carbon content is lower, the consistency of the carbon content is obviously improved, and the consistency of the magnetic performance of the sintered NdFeB magnet is generally improved.

Claims (10)

1. The utility model provides an improve sintering magazine of tombarthite permanent magnet material magnetism performance uniformity, its characterized in that includes upper end open-ended rectangle box body, rectangle box body pass through preceding curb plate, posterior lateral plate, left side board, right side board and bottom plate and arrange and connect gradually the constitution according to the position of controlling down, preceding curb plate posterior lateral plate left side board right side board and the bottom plate between enclose into rectangular material chamber, the upper end middle part of preceding curb plate be provided with the first recess of undercut, the upper end middle part of posterior lateral plate be provided with the second recess of undercut, the upper end middle part of left side board be provided with the third recess of undercut, the upper end middle part of right side board be provided with the fourth recess of undercut.
2. The sintering material box for improving the consistency of the magnetic properties of rare earth permanent magnetic materials according to claim 1, wherein the cross sections of the first groove, the second groove, the third groove and the fourth groove along the vertical direction are isosceles trapezoids, and the lower bottoms of the isosceles trapezoids are positioned above the upper bottoms of the isosceles trapezoids.
3. The sintering material box for improving the consistency of magnetic properties of rare earth permanent magnetic materials according to claim 2, wherein the heights of the cross sections of the first groove, the second groove, the third groove and the fourth groove along the vertical direction are not more than 5mm, the differences between the bottoms and the bottoms of the cross sections of the first groove, the second groove, the third groove and the fourth groove along the vertical direction are not more than 50mm, the area of the cross section of the first groove is 1% -3% of the area of the front side surface of the rectangular material cavity, the area of the cross section of the second groove is 1% -3% of the area of the rear side surface of the rectangular material cavity, the area of the cross section of the third groove is 1% -3% of the area of the left side surface of the rectangular material cavity, and the area of the cross section of the fourth groove is 1% -3% of the area of the right side surface of the rectangular material cavity.
4. The sintering material box for improving the consistency of the magnetic properties of rare earth permanent magnetic materials according to claim 1, wherein a first annular groove is formed in the bottom of the bottom plate, the depth of the first annular groove is smaller than the depth of the first groove, the depth of the second groove, the depth of the third groove and the depth of the fourth groove, and when a plurality of sintering material boxes are stacked up and down, the tops of the front side plate, the rear side plate, the left side plate and the right side plate of the sintering material box positioned in the next layer are embedded into the first annular groove formed in the bottom of the sintering material box positioned in the previous layer.
5. The sintering material box for improving the consistency of the magnetic properties of rare earth permanent magnetic materials according to claim 1, further comprising a cover plate, wherein a second annular groove is formed in the bottom of the cover plate, the depth of the second annular groove is smaller than the depth of the first groove, the second groove, the third groove and the fourth groove, and when the cover plate is arranged above the front side plate, the rear side plate, the left side plate and the right side plate, the tops of the front side plate, the rear side plate, the left side plate and the right side plate can be embedded into the second annular groove.
6. The sintering material box for improving the consistency of the magnetic properties of rare earth permanent magnetic materials according to claim 1, wherein the length of the front side plate along the left-right direction is 250-500mm, the height of the front side plate along the up-down direction is 30-80mm, the thickness of the rear side plate along the left-right direction is 5-12mm, the height of the rear side plate along the up-down direction is equal to the height of the front side plate along the up-down direction, and the thickness of the rear side plate along the front-rear direction is equal to the thickness of the front side plate along the front-rear direction; the length of the left side plate along the front-back direction is 250-500mm, the height of the left side plate along the up-down direction is 30-80mm, the thickness of the right side plate along the left-right direction is 5-12mm, the length of the right side plate along the front-back direction is equal to the length of the left side plate along the front-back direction, the height of the right side plate along the up-down direction is equal to the height of the left side plate along the up-down direction, and the thickness of the right side plate along the left-right direction is equal to the thickness of the left side plate along the left-right direction.
7. The sintering material box for improving the consistency of the magnetic properties of rare earth permanent magnetic materials according to claim 1, wherein the front side plate, the rear side plate, the left side plate, the right side plate and the bottom plate are made of graphite or carbon fiber.
8. A method for improving consistency of magnetic properties of rare earth permanent magnet materials is characterized by comprising the following steps:
(1) Preparing a material according to a formula of the rare earth permanent magnet material, and obtaining a cast sheet through a rapid hardening and sheet throwing technology;
(2) Hydrogen crushing the cast sheet to obtain alloy coarse powder, and then filling the alloy coarse powder into a tank body protected by inert gas for preservation;
(3) Transferring the alloy coarse powder into an air flow grinding device for grinding to obtain fine powder with the granularity D50 of 4.0-4.5 mu m, and then filling the fine powder into a tank body protected by inert gas, wherein oxygen supplementing is carried out according to the process requirements during the grinding process of the air flow grinding device, and the online oxygen content of the air flow grinding device is kept between 0 and 50 ppm;
(4) Transferring the fine powder to a forming workshop, performing compression forming on the fine powder through a press to obtain a blank, packaging the blank with a vacuum packaging bag, and packaging with a vacuum packaging machine, wherein inert gas is always filled into the press in the compression forming process, and the oxygen content is always lower than 0.02%;
(5) The packaged blank is sent into a sintering film stripping glove box after being subjected to water isostatic pressing treatment, and the oxygen content in the sintering film stripping glove box is reduced to below 0.02 percent;
(6) In a sintering film stripping glove box, film stripping treatment is carried out on blanks, the blanks are taken out from a vacuum packaging bag and then are arranged in a sintering material box which is placed in the sintering film stripping glove box in advance, the sintering material box comprises a rectangular box body with an opening at the upper end, the rectangular box body is formed by splicing a front side plate, a rear side plate, a left side plate, a right side plate and a bottom plate according to the directions of front, rear, left and right sides, rectangular material cavities for arranging the blanks are formed between the front side plate, the rear side plate, the right side plate and the bottom plate in a surrounding manner, a first concave groove which is downwards concave is formed in the middle of the upper end of the front side plate, a second concave groove which is downwards concave is formed in the middle of the upper end of the rear side plate, a third concave groove which is downwards concave is formed in the middle of the upper end of the left side plate, and a fourth concave groove which is downwards concave is formed in the middle of the upper end of the right side plate;
(7) Under the protection of nitrogen, stacking the sintering material boxes filled with blanks up and down according to the furnace loading amount, covering a cover plate on the uppermost sintering material box, and then orderly arranging the stacked sintering material boxes in a furnace chamber of a sintering furnace for high-temperature sintering in a furnace back feeding mode, wherein the high-temperature sintering process adopts a vibration sintering process, and the specific process is as follows: heating for 20min-50min to 330-430 ℃, then repeating the cooling and heating process for 2-5 times, then continuously heating for 60min-120min to 540-650 ℃ and preserving heat for 1h-3h, then heating for 60min-120min to 780-900 ℃ and preserving heat for 1h-3h, continuously heating for 20min-50min to 900-980 ℃ and preserving heat for 1h-3h, then continuously heating for 30min-60min to 1000-1100 ℃ and preserving heat for 3h-8h, finally performing subsequent aging treatment, and discharging after the aging treatment is finished to obtain a sintered neodymium iron boron magnet, namely a rare earth permanent magnet material, wherein the cooling and heating process each time is as follows: firstly cooling for 20min-50min, wherein the cooling amplitude is 40-80 ℃, and then heating for 20min-50min to 330-430 ℃.
9. The method for improving the consistency of magnetic properties of rare earth permanent magnetic materials according to claim 8, wherein the cross sections of the first groove, the second groove, the third groove and the fourth groove along the vertical direction are isosceles trapezoids, and the lower bottoms of the isosceles trapezoids are positioned above the upper bottoms of the first groove, the second groove, the third groove and the fourth groove.
10. The method for improving the magnetic property consistency of rare earth permanent magnet materials according to claim 8, wherein the heights of the cross sections of the first groove, the second groove, the third groove and the fourth groove in the vertical direction are not more than 5mm, the differences between the bottoms and the bottoms of the cross sections of the first groove, the second groove, the third groove and the fourth groove in the vertical direction are not more than 50mm, the area of the cross section of the first groove is 1% -3% of the area of the front side surface of the rectangular material cavity, the area of the cross section of the second groove is 1% -3% of the area of the rear side surface of the rectangular material cavity, the area of the cross section of the third groove is 1% -3% of the area of the left side surface of the rectangular material cavity, and the area of the cross section of the fourth groove is 1% -3% of the area of the right side surface of the rectangular material cavity.
CN202310960548.XA 2023-08-02 2023-08-02 Sintering material box and method for improving consistency of magnetic properties of rare earth permanent magnet material Pending CN116652182A (en)

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CN114054753A (en) * 2021-11-22 2022-02-18 中钢天源股份有限公司 Material box for sintering neodymium iron boron and sintering method
CN115938709A (en) * 2022-11-30 2023-04-07 福建省长汀金龙稀土有限公司 Magnetic steel containing high-abundance rare earth elements and preparation method and application thereof
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004053147A (en) * 2002-07-22 2004-02-19 Imae Kogyo Kk Sintering setter
CN104729293A (en) * 2015-03-20 2015-06-24 重庆科技学院 Flowing atmosphere hot/cold impact sintering resistance furnace
CN105935768A (en) * 2016-06-30 2016-09-14 中铝广西有色金源稀土有限公司 Sintered Nd-Fe-B open type sintering feed box and use method thereof
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CN116313483A (en) * 2023-03-23 2023-06-23 包头韵升强磁材料有限公司 Method for reducing deformation of sheet sintered NdFeB magnet blank

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