CN109727742A

CN109727742A - A kind of low heavy rare earth NdFeB material and preparation method thereof

Info

Publication number: CN109727742A
Application number: CN201910063592.4A
Authority: CN
Inventors: 罗立伟
Original assignee: NINGBO HESHENG MAGNETIC CO Ltd
Current assignee: NINGBO HESHENG MAGNETIC CO Ltd
Priority date: 2019-01-23
Filing date: 2019-01-23
Publication date: 2019-05-07

Abstract

The invention discloses a kind of low heavy rare earth NdFeB materials, it is characterized in that, by following component according to mass percentage composition: Pr+Nd25 ~ 30%, Dy0.2 ~ 5%, Zr0.05 ~ 0.1%, B0.98 ~ 1%, Co0.1 ~ 1%, Ga0.1 ~ 0.3%, Al0.1 ~ 0.4%, Cu0.1 ~ 0.3%, Tb0 ~ 0.8%, Fe surplus.It is prepared as follows: (1) preparing major-minor slab of the thickness at 1 ~ 4 μm；(2) major-minor phase slab hydrogen flour body is prepared；(3) magnetic powder is prepared using airflow milling；(4) molding, etc. static pressure；(5) it is sintered.Compared with prior art, it is an advantage of the invention that due to using Dy instead of Tb, so that the expense of the NdFeB material of per kilogram has dropped 3~8%；It is reduced sintering temperature instead of Nb with Zr and is easy to be sintered, and shown according to test data, the performance of NdFeB material of the present invention uses the performance indicator of material when heavy rare earth metal Tb consistent with traditional additive.

Description

A kind of low heavy rare earth NdFeB material and preparation method thereof

Technical field

Material Field of the present invention more particularly to a kind of low heavy rare earth NdFeB material and preparation method thereof.

Background technique

NdFeB material is a kind of magnetic material, has high energy product, coercivity and energy density, is known as magnetic king, because This, is widely used in the fields such as electronics, toy, packaging, space flight and aviation and automobile.

The tetragonal crystal that its main ingredient rare earth essence neodymium (Nd) and iron (Fe), boron (B) are formed, in order to obtain not It can be substituted with other rare earth metals such as part dysprosium (Dy), praseodymium (Pr) with performance, iron can also be by the metal substitutes such as cobalt (Co), aluminium, boron Content it is smaller, but important function is surpassed to the tetragonal structure intermetallic compound of formation, so that compound has height Saturation magnetization, uniaxial anisotropy and Curie temperature.Neodymium-iron-boron magnetic material is divided into according to maximum magnetic energy product multiple The trade mark, such as N30-N52,30M-50M, 30H-50H, 30SH-48SH, 28UH-45UH, 28EH-40EH.

With industrial development, the volume that magnetic material uses constantly reduces, this requires the magnet steel of high energy product to meet The requirement that volume reduces.This makes NdFeB material application more and more wider, and requirement of the market to neodymium iron boron performance is tighter Lattice have very in practical applications such as using N52,50M, 48H, 45SH and 42UH as the trade mark of high energy product in each serial trade mark The big market demand.Due to the aforementioned magnetic trade mark, the formulation cost and process costs of most of producer's production are relatively high, largely The market demand and high price cost formed contradiction.

It therefore, can be very with the exploitation of the high grade neodymium-iron-boron material of the low heavy rare earth such as N52,50M, 48H, 45SH and 42UH It reduces the production cost of enterprise in big degree and obtains market, client can obtain required high energy product also with lower price N52, obtain the situation of two-win.

In the prior art, fabrication processing is as follows:

Ingredient → melting ingot/, which is got rid of band → powder → die mould → sintering tempering → magnetic detection → mill processing → pin processed and cut, to be added Work → plating → finished product.

Most improved magnetic materials are improved slightly by above-mentioned technique, as number of patent application 2016111575459 discloses one Kind Nd-Fe-B permanent magnet material, specifically comprises the following steps:

(1) ingredient melting is obtained into magnetic ingot, then wears into magnetic powder；

(2) Surface Treatment with Plasma is carried out to above-mentioned magnetic powder by Zn-Al alloy powder；

(3) fluorinated graphene is prepared, is then added in above-mentioned (2), obtains mixture；

(4) static pressure, vacuum-sintering, Primary product, then carry out Surface Treatment with Plasma；

(5) after radiation polymerization erosion resistant coating, finished product is obtained.

The neodymium-iron-boron magnetic material of above-mentioned modification, although improving magnetic energy product, its manufacturing process is longer, is changed Property after magnetic density of material do not get a promotion, cost rises instead, can not obtain market approval cheap magnetic Property material.

Summary of the invention

Present invention seek to address that the above problem, by formula and process modification, to increase magnetic material density to obtain more The low heavy rare earth NdFeB material of high energy product.

To achieve this purpose, the present invention adopts the following technical scheme:

A kind of low heavy rare earth NdFeB material, by following component according to mass percentage composition:

Above-mentioned low heavy rare earth NdFeB material, is made in accordance with the following steps:

(1) slab

It is designed according to above-mentioned formula, main-phase alloy and secondary phase alloy is made, and be respectively implanted in slab equipment and cast Piece crystallization, control slab crystallization thickness is in 0.1~0.45mm；

(2) the broken processing of hydrogen

The broken processing of hydrogen will be first carried out after main phase slab and secondary phase slab proportionally 94~95% and 5~6% mixing；

(3) airflow milling powder

Then slab of the above-mentioned hydrogen after broken is worn into powder using airflow milling, granularity is controlled in D50:4.9~5.3 μm, SMD:2.95~3.15 μm obtain magnetic powder；

(4) molding/static pressure

Magnetic powder in step (3) is formed by moulding press green compact, Vacuum Package, after waiting static pressure, oil pressure, Green compact are made；

(5) it is sintered

Green compact obtained in step (4) are handled by sintering furnace, sintering temperature control is at 1040~1080 DEG C, level-one Tempering temperature is 880~1000 DEG C, and second annealing temperature is 480~530 DEG C, makes the control of its compact density 7.5~7.6 Blank material, and make degassing completely, it shrinks and crystal grain is grown up uniformly, low heavy rare earth NdFeB material.

Preferably, it prepares magnetic trade mark N52 to be made of by mass percentage following component: Pr+Nd 28~30%, Dy 0.2 ~0.5%, Zr 0.05~0.1%, B 0.98~1%, Co 0.1~0.3%, Ga 0.1~0.3%, Al 0.1~ 0.3%, Cu 0.1~0.3% and Fe surplus.

Preferably, above-mentioned magnetic trade mark N52 is prepared, wherein selection main phase slab and secondary phase slab ratio point in step (2) It Wei 95.5% and 4.5%；Step (3) is anaerobic grinding, and selecting sintering temperature in step (5) is 1040~1060 DEG C, level-one Tempering temperature is 880~1000 DEG C, and second annealing temperature is 500~530 DEG C.

Preferably, it prepares magnetic trade mark 50M to be made of by mass percentage following component: Pr+Nd 28~30%, Dy 0.5 ~1.5%, Zr 0.08~0.1%, B 0.98~1%, Co 0.1~0.3%, Ga 0.1~0.3%, Al 0.1~ 0.3%, Cu 0.1~0.3% and Fe surplus.

Preferably, magnetic trade mark 48H is prepared to be made of by mass percentage following component: Pr+Nd 28~30%, Dy 1~ 2%, Zr 0.08~0.1%, B 0.98~1%, Co 0.1~0.3%, Ga 0.1~0.3%, Al 0.2~0.4%, Cu 0.1~0.3% and Fe surplus.

Preferably, it prepares magnetic trade mark 45SH to be made of by mass percentage following component: Pr+Nd 26~28%, Dy 2 ~3%, Zr 0.05~0.1%, B 0.98~1%, Co 0.6~1%, Ga 0.1~0.3%, Al 0.2~0.4%, Cu 0.1~0.3% and Fe surplus.

Preferably, magnetic trade mark 42UH is prepared to be made of by mass percentage following component: Pr+Nd 25~27%, Dy 4~ 5%, Zr 0.08~0.1%, B 0.98~1%, Co 0.1~0.3%, Ga 0.1~0.3%, Al 0.2~0.4%, Cu 0.1~0.3%, Tb 0.5~0.8% and Fe surplus.

The invention has the benefit that

1. more original old formula is compared, heavy rare earth niobium is replaced using metal zirconium, increases dysprosium content and substitutes or remove and is low Heavy rare earth terbium content, reaches the purpose for reducing cost.

2. the blank of higher density is obtained using static pressure and oil pressure cntrol density using airflow milling Control granularity size, Improve magnetic energy product.

3. compared with prior art, it is an advantage of the invention that due to using Dy instead of Tb, so that the neodymium iron boron of per kilogram The expense of material has dropped 3~8%；It is reduced sintering temperature instead of Nb with Zr and is easy to be sintered, and shown according to test data, The performance of NdFeB material of the present invention uses the performance indicator of material when heavy rare earth metal Tb consistent with traditional additive.

Specific embodiment

The technical scheme of the invention is further explained by means of specific implementation.

Embodiment 1

The present embodiment is the low heavy rare earth NdFeB material that magnetic trade mark N52 is embodied, by mass percentage, by as follows Formula shown in table 1:

Table 1

Above-mentioned table 1 is formulated, is prepared as follows:

(1) slab

It is designed according to above-mentioned formula, main-phase alloy and secondary phase alloy is made, and be respectively implanted in slab equipment and cast Piece crystallization, when melting is cast, to accelerate and guaranteeing that crystallisation by cooling of the slab in casting is more stable, copper rod inflow temperature control System is at 10~25 DEG C, and for the thickness for controlling slab, copper roller revolving speed is controlled at 38 rpms, and slab is finally crystallized thickness control System is in 0.1~0.45mm.

(2) the broken processing of hydrogen

The broken processing of hydrogen will be first carried out after main phase slab and secondary phase slab proportionally 94.5% and 5.5% mixing, is prepared into The broken magnet of hydrogen.

(3) main phase slab of the above-mentioned hydrogen after broken is then worn into powder with secondary phase slab using airflow milling, is examined using granularity Instrument detection is surveyed, granularity is controlled in D50:4.95~5.35 μm, SMD:3.0~3.2 μm respectively obtain major and minor phase magnetic powder；

(4) molding/static pressure

Major and minor phase magnetic powder in step (3) is formed by moulding press green compact, Vacuum Package, using equal static pressure, After oil pressure, green compact magnet is made；

(5) it is sintered

Green compact obtained in step (4) are handled by sintering furnace, sintering temperature control is at 1040~1060 DEG C, level-one Tempering temperature is 880~1000 DEG C, and second annealing temperature is 480~530 DEG C, makes the control of its compact density 7.5~7.6 Blank material, and make degassing completely, it shrinks and crystal grain is grown up uniformly, magnet after being sintered.

In the above-mentioned preparation process, whole protection against oxidation influences final magnetism to protect magnetic powder that oxidation does not occur Energy.

N52 magnet manufactured in the present embodiment has following features compared with the formula of N52 before:

Table 2

Table 2 is formula of my the original corporation for N52.

Sintered blank magnet is subjected to six face polishings with big Vertical Mill grinding machine, leaching in thermostatic water bath is then placed in and sets 20- 30 minutes, water temperature was set as 20 DEG C, finally takes out and dries, carries out magnetic parameter survey with AMT-4 magnetic property automatic measuring instrument Amount.

Specific test result is as shown in table 3, table 4:

Table 3

Table 4

Table 3 is that original formula is prepared, and table 4 is that the present embodiment formula is prepared.

As can be seen from the above table, reduce production cost after N52 in terms of magnetic parameter comparison, br, Hcj, BH's Value is substantially close, and the older technique of HK/Hcj will be slightly good and stablizes.(GB/T13560-2017 national standard N52:br " 14.2, Hcj " 12, BH:49-53、Hk/Hcj》95)

Present embodiment, compared with prior art, it is an advantage of the invention that due to using Dy instead of Tb, so that every public affairs The expense of the NdFeB material of jin has dropped 3~5%；It is reduced sintering temperature instead of Nb with Zr and is easy to be sintered, and according to survey It tries data to show, the performance of the material when performance of NdFeB material of the present invention and traditional additive are using heavy rare earth metal Tb Index is consistent, Br14.3~14.6, Hcj " 12, BH " 50, Hk/Hcj " 95%, production cost reduces by 3~5% than before.Separately Outside, the N52 material that old technique, old formula produce before comparing in terms of machining machinability has obvious promotion.Cause There is biggish application market in this block field in electroacoustic for N52, so the small column within some diameter D18 of production requires Punching, the material client that produces before and machining feedback machinability are poor, and when punching is easy to crack.Change by formula, technique After good, qualification rate of the N52 in machining process is obviously improved.

Embodiment 2

The present embodiment is used to prepare the magnet material of magnetic trade mark 50M, forms by mass percentage by following component:

Pr+Nd 28~30%, Dy 0.5~1.5%, Zr 0.08~0.1%, B 0.98~1%, Co 0.1~ 0.3%, Ga 0.1~0.3%, Al 0.1~0.3%, Cu 0.1~0.3% and Fe surplus.

By above-mentioned formula, prepare as follows:

(1) slab

(2) the broken processing of hydrogen

(3) main phase slab of the above-mentioned hydrogen after broken is then worn into powder with secondary phase slab using airflow milling, is examined using granularity Instrument detection is surveyed, granularity is controlled in D50:4.90~5.30 μm, SMD:2.95~3.15 μm respectively obtain major and minor phase magnetic powder.

(4) molding/static pressure

Major and minor phase magnetic powder in step (3) is formed by moulding press green compact, Vacuum Package, using equal static pressure, After oil pressure, green compact magnet is made.

(5) it is sintered

Green compact obtained in step (4) are handled by sintering furnace, sintering temperature control is at 1050~1070 DEG C, level-one Tempering temperature is 880~1000 DEG C, and second annealing temperature is 490~530 DEG C, makes the control of its compact density 7.5~7.6 Blank material, and make degassing completely, it shrinks and crystal grain is grown up uniformly, magnet after being sintered.

Originally my corporation was as shown in table 5 for 50M formula:

Table 5

Measurement is respectively as shown in table 6, table 7

Table 6

Table 7

Table 6 is original formula test result

Table 7 is the present embodiment test result

By above-mentioned comparison, low heavy rare earth and the 50M after cost declining are changed in terms of magnetic parameter comparison, br relatively low one Point, Hcj improve that many, the value of BH is more slightly lower, and the older technique of HK/Hcj will be slightly good and stablizes.(GB/T13560-2017 state Mark 50M:br " 13.9, Hcj " 14, BH:47-51, Hk/Hcj " 95).

Compared with prior art, advantage is using Dy instead of Tb, so that the NdFeB material of per kilogram the present embodiment Expense have dropped 5~8%；It is reduced sintering temperature instead of Nb with Zr and is easy to be sintered, and shown according to test data, this board The performance of the NdFeB material of number 50M uses the performance indicator of material when heavy rare earth metal Tb consistent with traditional additive. Br " 14.0, Hcj " 14, BH " 48, Hk/Hcj " 95%, the material of the old and new's process recipe is compared, discovery is omited in terms of machinability There is promotion, but is not apparent.But in zero-G test comparison, discovery new process is obviously better than old technique very much, and opposite Consistency is stablized.This has good promotion to 50M magnet prolonging the service life in the presence of a harsh environment.

Embodiment 3

The present embodiment is used to prepare magnetic trade mark 48H magnet material, is specifically made of by mass percentage following component:

Pr+Nd 28~30%, Dy 1~2%, Zr 0.08~0.1%, B 0.98~1%, Co 0.1~0.3%, Ga 0.1~0.3%, Al 0.2~0.4%, Cu 0.1~0.3% and Fe surplus.

By above-mentioned formula, prepare as follows:

(1) slab

(2) the broken processing of hydrogen

The broken processing of hydrogen will be first carried out after main phase slab and secondary phase slab proportionally 94% and 6% mixing, it is broken to be prepared into hydrogen Magnet.

(3) main phase slab of the above-mentioned hydrogen after broken is then worn into powder with secondary phase slab using airflow milling, is examined using granularity Instrument detection is surveyed, granularity is controlled in D50:4.95~5.35 μm, SMD:3.0~3.2 μm respectively obtain major and minor phase magnetic powder.It should Oxygenation control is in 5~10ppm in the process.

(4) molding/static pressure

Major and minor phase magnetic powder in step (3) is formed by moulding press green compact, Vacuum Package, using equal static pressure, The secondary compacting of oil pressure makes green density improve and be evenly distributed, and green compact magnet is made.

(5) it is sintered

Green compact obtained in step (4) are handled by sintering furnace, sintering temperature control is at 1060~1080 DEG C, level-one Tempering temperature is 880~1000 DEG C, and second annealing temperature is 480~520 DEG C, makes the control of its compact density 7.5~7.6 Blank material, and make degassing completely, it shrinks and crystal grain is grown up uniformly, magnet after being sintered.

The magnetic trade mark 48H formula of my company's original production is as follows:

Table 8

Through the test mode in previous embodiment 1, test result is as follows:

Table 9

Table 10

Table 8 is original formula test result

Table 9 is the present embodiment test result

Table 9 is compared with table 8, and the 48H after cost declining is in terms of magnetic parameter comparison, and br is substantially close, Hcj slightly lower one Point, the value of BH are more slightly lower, and the older technique of HK/Hcj will be slightly good and stablizes.(GB/T13560-2017 national standard 48H:br " 13.7, Hcj》16、BH:45-49、Hk/Hcj》95)。

Compared with prior art, advantage of this embodiment is that due to using Dy instead of Tb, so that the neodymium iron boron of per kilogram The expense of material has dropped 8~10%；It with Zr instead of Nb, reduces sintering temperature and is easy to be sintered, and is aobvious according to test data Show, the performance indicator of the material when performance of NdFeB material and traditional additive are using heavy rare earth metal Tb in the present embodiment Unanimously；Br " 13.8, Hcj " 17, BH " 46, Hk/Hcj " 95%.

The old and new's Recipe production material by comparison, it was found that, new process production magnet steel in bending strength and resistance to compression There is obvious promotion in intensity, the magnet steel difference of the older technique production of other magnetic properties is almost unchanged.This 48H magnetic Steel can satisfy some demands for having and using product under directly contact and surge environment.

Embodiment 4

The present embodiment is used to prepare magnetic trade mark 45SH, is specifically made of by mass percentage following component: Pr+Nd 26~ 28%Dy 2~3%, Zr 0.05~0.1%, B 0.98~1%, Co 0.6~1%, Ga 0.1~0.3%, Al 0.2~ 0.4%, Cu 0.1~0.3% and Fe surplus.

By above-mentioned formula, prepare as follows:

(1) slab

It is designed according to above-mentioned formula, main-phase alloy and secondary phase alloy is made, and be respectively implanted in slab equipment and cast Piece crystallization, when melting is cast, to accelerate and guaranteeing that crystallisation by cooling of the slab in casting is more stable, copper rod inflow temperature control System is at 10~25 DEG C, and for the thickness for controlling slab, copper roller revolving speed is controlled at 40 rpms, and slab is finally crystallized thickness control System is in 0.1~0.45mm.

(2) the broken processing of hydrogen

The broken processing of hydrogen will be first carried out after main phase slab and secondary phase slab proportionally 95% and 5% mixing, it is broken to be prepared into hydrogen Magnet.

(3) main phase slab of the above-mentioned hydrogen after broken is then worn into powder with secondary phase slab using airflow milling, is examined using granularity Instrument detection is surveyed, granularity is controlled in D50:4.8~5.2 μm, SMD:2.9~3.1 μm respectively obtain major and minor phase magnetic powder.The mistake Oxygenation control is in 10~15ppm in journey.

(4) molding/static pressure

(5) it is sintered

Originally formula is as shown in table 10:

Table 10

Test result is as follows after above-mentioned Formulation Implementation:

Table 11

Table 12

Table 11 is original formula result；

Table 12 is that the present embodiment is formulated result.

45SH after cost declining in terms of magnetic parameter comparison, br is substantially close, Hcj slightly improve a bit, BH slightly mentions It is high a bit, the substantially close stabilization of HK/Hcj.(GB/T13560-2017 national standard 45SH:br " 13.3, Hcj " 20, BH:43-46, Hk/Hcj》90)

The present embodiment compared with prior art, its advantage is that due to using Dy instead of Tb, so that the neodymium iron boron of per kilogram The expense of material has dropped 8~10%, saves cost；With Zr instead of Nb, reduces sintering temperature and be easy to be sintered, and according to Test data shows that the performance and tradition additive of the NdFeB material of the present embodiment use material when heavy rare earth metal Tb Performance indicator it is consistent.

The 45SH magnetic property of new formula and the low heavy rare earth of process matched therewith production is relatively stable, Br13.3~13.7, Hcj " 20, BH " 43, Hk/Hcj " 95%, which has very big advantage in whole market is offered, well below general producer. It is compared by the old and new's Recipe material, in addition to degradation is slightly poorer than old Recipe, remaining zero-G test, machining Property is obviously improved, and magnetic property can stably reach international standard.

Embodiment 5

Preferably, it prepares magnetic trade mark 42UH to be made of by mass percentage following component: Pr+Nd 25~27%, Dy 4 ~5%Zr 0.08~0.1%, B 0.98~1%, Co 0.1~0.3%, Ga 0.1~0.3%, Al 0.2~0.4%, Cu 0.1~0.3%, Tb 0.5~0.8% and Fe surplus.

By above-mentioned formula, prepare as follows:

(1) slab

(2) the broken processing of hydrogen

(3) main phase slab of the above-mentioned hydrogen after broken is worn into powder with secondary phase slab using airflow milling, utilizes granularity Detection instrument Detection controls granularity in D50:4.9~5.3 μm, and SMD:2.95~3.15 μm respectively obtain major and minor phase magnetic powder.The process Middle oxygenation control is in 10~20ppm.

(4) form/wait static pressure/oil pressure

(5) it is sintered

In entire production process in addition to pulverizing process adds micro- oxygen, the design of remaining process full set protection against oxidation, with Protecting magnetic powder that oxidation does not occur influences final magnetic property.

Originally our company produces the formula of 42UH trade mark magnet:

Table 13

Test result is as follows:

Table 14

Table 15

Table 14 is original formula test result

Table 15 is the present embodiment test result

By comparing discovery in table, the 42UH after cost declining is in terms of magnetic parameter comparison, the basic phase of br, Hcj, BH Closely, HK/Hcj will be slightly good and stablizes.(GB/T13560-2017 national standard 42UH:br " 12.9, Hcj " 25, BH:40-43, Hk/ Hcj》90)。

Compared with prior art, advantage of this embodiment is that due to using Dy instead of most of Tb and a small amount of Pr+Nd, Since the price of Tb is three times of Dy, so that the expense of the NdFeB material of per kilogram has dropped 8~10%, cost is saved, And it is shown according to test data, the material when performance of the present embodiment NdFeB material and traditional additive are using heavy rare earth metal Tb The performance indicator of material is consistent；The 42UH magnetic property of new formula and the low heavy rare earth of process matched therewith production is relatively stable, and Br12.8~ 13, Hcj " 25, BH " 40, Hk/Hcj " 90%, the older Recipe of the production cost of new Recipe reduces by 8~10%.

The material items Experimental Comparison discovery of the old and new's Recipe production, the material zero-G test of new Recipe production (corrosion resistance) this use to being conducive to 42UH in some moist adverse circumstances.

The technical principle of the invention is described above in combination with a specific embodiment.These descriptions are intended merely to explain of the invention Principle, and shall not be construed in any way as a limitation of the scope of protection of the invention.Based on the explanation herein, the skill of this field Art personnel can associate with other specific embodiments of the invention without creative labor, these modes all will It falls under the scope of the present invention.

Claims

1. a kind of low heavy rare earth NdFeB material, which is characterized in that by following component according to mass percentage composition:

Pr+Nd 25~30%

Dy 0.2~5%

Zr 0.05~0.1%

B 0.98~1%

Co 0.1~1%

Ga 0.1~0.3%

Al 0.1~0.4%

Cu 0.1~0.3%

Tb 0~0.8%

Fe surplus

(1) slab

It is designed according to above-mentioned formula, main-phase alloy and secondary phase alloy is made, and be respectively implanted progress slab knot in slab equipment Crystalline substance, control slab crystallization thickness is in 0.1 ~ 0.45mm；

(2) the broken processing of hydrogen

The broken processing of hydrogen will be first carried out after main phase slab and secondary phase slab proportionally 94 ~ 96% and 4 ~ 6% mixing;

(3) airflow milling powder

Then slab of the above-mentioned hydrogen after broken is worn into powder using airflow milling, granularity is controlled in D50:4.9~5.3 μm, SMD: 2.95~3.15 μm, obtain magnetic powder;

Molding/static pressure

Magnetic powder in step (3) is formed by moulding press green compact, life is made after waiting static pressure, oil pressure in Vacuum Package Base；

(5) it is sintered

Green compact obtained in step (4) are handled by sintering furnace, at 1040~1080 DEG C, level-one tempering is warm for sintering temperature control Degree is 880~1000 DEG C, and second annealing temperature is 480~530 DEG C, makes blank material of its compact density control 7.5~7.6 Material, and make degassing completely, it shrinks and crystal grain is grown up uniformly, low heavy rare earth NdFeB material.

2. a kind of low heavy rare earth NdFeB material as described in claim 1, which is characterized in that prepare magnetic trade mark N52 by as follows Component forms by mass percentage: Pr+Nd 28 ~ 30%, Dy 0.2 ~ 0.5%, Zr 0.05 ~ 0.1%, B 0.98 ~ 1%, Co 0.1 ~ 0.3%, Ga 0.1 ~ 0.3%, Al 0.1 ~ 0.3%, Cu 0.1 ~ 0.3% and Fe surplus.

3. a kind of low heavy rare earth NdFeB material as claimed in claim 2, which is characterized in that it prepares in magnetic trade mark N52 step, Step (2) selection main phase slab and secondary phase slab ratio are respectively 95.5% and 4.5%, and step (3) is anaerobic grinding, step (5) Middle to select sintering temperature be 1040~1060 DEG C, and level-one tempering temperature is 880~1000 DEG C, and second annealing temperature is 500~530 ℃。

4. a kind of low heavy rare earth NdFeB material as described in claim 1, which is characterized in that prepare magnetic trade mark 50M by as follows Component forms by mass percentage: Pr+Nd 28 ~ 30%, Dy 0.5 ~ 1.5%, Zr 0.08 ~ 0.1%, B 0.98 ~ 1%, Co 0.1 ~ 0.3%, Ga 0.1 ~ 0.3%, Al 0.1 ~ 0.3%, Cu 0.1 ~ 0.3% and Fe surplus.

5. a kind of low heavy rare earth NdFeB material as described in claim 1, which is characterized in that prepare magnetic trade mark 48H by as follows Component forms by mass percentage: Pr+Nd 28 ~ 30%, Dy 1 ~ 2%, Zr 0.08 ~ 0.1%, B 0.98 ~ 1%, Co 0.1 ~ 0.3%, Ga 0.1 ~ 0.3%, Al 0.2 ~ 0.4%, Cu 0.1 ~ 0.3% and Fe surplus.

6. a kind of low heavy rare earth NdFeB material as described in claim 1, which is characterized in that prepare magnetic trade mark 45SH by as follows Component forms by mass percentage: Pr+Nd 26 ~ 28%, Dy 2 ~ 3%, Zr 0.05 ~ 0.1%, B 0.98 ~ 1%, Co 0.6 ~ 1%, Ga 0.1 ~ 0.3%, Al 0.2 ~ 0.4%, Cu 0.1 ~ 0.3% and Fe surplus.

7. a kind of low heavy rare earth NdFeB material as described in claim 1, which is characterized in that prepare magnetic trade mark 42UH by as follows Component forms by mass percentage: Pr+Nd 25 ~ 27%, Dy 4 ~ 5%, Zr 0.08 ~ 0.1%, B 0.98 ~ 1%, Co 0.1 ~ 0.3%, Ga 0.1 ~ 0.3%, Al 0.2 ~ 0.4%, Cu 0.1 ~ 0.3%, Tb 0.5 ~ 0.8% and Fe surplus.