CN115910584A - Low-heat-demagnetization-rate bonded neodymium-iron-boron magnet and preparation method thereof - Google Patents

Abstract

The invention discloses a bonded neodymium iron boron magnet with low heat demagnetization rate, which is prepared from neodymium iron boron magnetic powder, and has low heat demagnetization rate, and the preparation method of the bonded neodymium iron boron magnet comprises the following steps: the production method comprises the following steps of S1, preparing powder, mixing neodymium iron boron magnetic powder with a bonding agent to prepare magnetic rubber powder, S2, forming the magnetic rubber powder into a pressed blank through an automatic press, S3, curing the pressed blank through curing equipment to enable a product to reach certain mechanical strength, S4, carrying out surface treatment, carrying out anti-corrosion treatment on the surface of the pressed blank to improve the oxidation resistance of the magnet, S5, magnetizing the magnet through a magnetizing machine, a magnetizing coil and a special clamp, S6, carrying out heat treatment, carrying out low-temperature heat treatment on the magnetized magnet, carrying out heat treatment at the temperature of 80-120 ℃, carrying out heat treatment for 0.5-4 h, S7, packaging and delivering, carrying out inspection on the magnet after heat treatment, and packaging and delivering the magnet qualified through inspection according to requirements.

Description

Low-heat-demagnetization-rate bonded neodymium-iron-boron magnet and preparation method thereof

Technical Field

The invention relates to the technical field of bonded neodymium iron boron magnets, in particular to a bonded neodymium iron boron magnet with low heat demagnetization rate and a preparation method thereof.

Background

The bonded neodymium iron boron has the advantages of good formability, high dimensional precision, good magnetic property uniformity, large degree of freedom of shape, low production energy consumption and the like, and is widely applied to the fields of computers, electronic technologies, household appliances, office supplies, automobiles and the like;

with the continuous expansion of the application field of the bonded neodymium iron boron, the market demand is continuously strong, the client's understanding of the product is continuously improved, as a key index of the high-performance bonded neodymium iron boron, the thermal demagnetization index gradually becomes the focus of attention of the client as the indexes such as the magnetic flux value, the remanence, the coercive force, the magnetic energy product and the like of the magnet, namely, the magnet is baked for a certain time at high temperature, such as 100 ℃,120 ℃ and the like, and then cooled to room temperature, and then the magnetic flux/surface magnetism of the magnet is attenuated according to the attenuation ratio of the magnetic flux/surface magnetism of the magnet to the magnetic flux/surface magnetism of the magnetic steel before baking, and the smaller the attenuation ratio is, the better the temperature resistance of the magnet is;

at present, three methods for improving the thermal demagnetization rate of bonded neodymium iron boron magnets in the industry are mainly used: the first method is a grain refinement method, the bonded neodymium iron boron magnetic powder generally adopts a rapid quenching method, the magnetic powder obtains a nanocrystalline structure after crystallization, the diameter of grains is tens of nanometers, the antimagnetic attenuation capability of the magnetic powder is greatly improved, the second method is to add trace elements such as Co and the like to improve the temperature coefficient of the magnetic powder and improve the antimagnetic attenuation capability, but the method has limited action, the third method is to add heavy rare earth elements such as Dy and Tb and the like into the magnetic powder to generate a higher anisotropic field phase Dy (Tb) 2Fe14B, dy (Tb) 2Fe14B in the magnetic powder, the antimagnetic attenuation capability is improved by improving the intrinsic coercive force of the magnet, the method is effective, but the material cost is greatly improved, the residual magnetic value of the magnetic powder is greatly reduced, so that the magnetic flux/surface magnetism of the bonded neodymium iron boron magnet is reduced, the method can be used on some products with low magnetic flux/surface magnetism requirements, but on elements with higher and higher magnetic flux/surface magnetism requirements, the method is limited, the three measures need to finish the preparation of the magnetic powder in the process, and once the magnetic flux/surface magnetism index is reduced;

accordingly, one skilled in the art provides a bonded ndfeb magnet with low thermal demagnetization rate and a method for manufacturing the same to solve the problems set forth in the background art.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a bonded neodymium iron boron magnet with low heat demagnetization rate and a preparation method thereof.

The technical scheme adopted by the invention for solving the technical problems is as follows: the utility model provides a low heat subtracts magnetic rate bonding neodymium iron boron magnetism body, includes the neodymium iron boron magnetism body, the neodymium iron boron magnetism body is made by the neodymium iron boron magnetic, the neodymium iron boron magnetism body has low heat and subtracts magnetic rate.

Preferably, the thermal demagnetization rate of the neodymium iron boron magnet is less than 1%.

Preferably, the thermal demagnetization rate of the neodymium iron boron magnet is less than 3%.

Preferably, the NdFeB magnetic powder is BNP-6, BNP-8, BNP-9, BNP-10, BNP-11 or BNP-12.

A preparation method of a neodymium iron boron magnet comprises the following steps:

step S1, pulverizing, namely mixing neodymium iron boron magnetic powder with a bonding agent to prepare magnetic rubber powder;

s2, molding, namely molding the magnetic glue powder into a pressing blank by an automatic press;

s3, curing, namely curing the pressed blank by using curing equipment to ensure that the product reaches certain mechanical strength;

s4, performing surface treatment, namely performing anti-corrosion treatment on the surface of the pressed blank to improve the oxidation resistance of the magnet;

s5, magnetizing, namely magnetizing the magnet through a magnetizing machine, a magnetizing coil and a special clamp;

s6, performing heat treatment, namely performing low-temperature heat treatment on the magnetized magnet, wherein the temperature range of the heat treatment is 80-120 ℃, and the time of the heat treatment is 0.5-4 h;

and S7, packaging and delivering, namely inspecting the heat-treated magnet, and packaging and delivering the qualified magnet according to the requirement.

Compared with the prior art, the invention has the beneficial effects that:

compared with the 3-10% thermal demagnetization rate of the traditional magnet, the bonded neodymium iron boron magnet with the low thermal demagnetization rate can reduce the thermal demagnetization rate of the bonded neodymium iron boron magnet to be within 3%, even can be controlled to be within 1%, can meet the requirement on thermal demagnetization indexes, is relatively simple in process, convenient, effective, obvious in cost advantage and suitable for automatic, intelligent and large-scale preparation.

Drawings

Fig. 1 is a flow chart of a preparation process of the bonded neodymium iron boron magnet with low thermal demagnetization rate.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

As shown in fig. 1, the invention provides a bonded neodymium iron boron magnet with low heat demagnetization rate, which comprises a neodymium iron boron magnet, wherein the neodymium iron boron magnet is made of neodymium iron boron magnetic powder and has low heat demagnetization rate.

The thermal demagnetization rate of the neodymium iron boron magnet is less than 1%.

The thermal demagnetization rate of the neodymium iron boron magnet is less than 3%.

The neodymium iron boron magnetic powder is BNP-6 or BNP-8 or BNP-9 or BNP-10 or BNP-11 or BNP-12.

A preparation method of a neodymium iron boron magnet comprises the following steps:

step S1, pulverizing, namely mixing neodymium iron boron magnetic powder with a bonding agent to prepare magnetic rubber powder;

s2, molding, namely molding the magnetic glue powder into a pressing blank through an automatic press;

s3, solidifying, namely solidifying the pressed blank through solidification equipment to ensure that the product reaches certain mechanical strength;

s4, performing surface treatment, namely performing anti-corrosion treatment on the surface of the pressed blank to improve the oxidation resistance of the magnet;

s5, magnetizing, namely magnetizing the magnet through a magnetizing machine, a magnetizing coil and a special clamp;

s6, performing heat treatment, namely performing low-temperature heat treatment on the magnetized magnet, wherein the temperature range of the heat treatment is 80-120 ℃, and the time of the heat treatment is 0.5-4 h;

and S7, packaging and delivering, inspecting the heat-treated magnet, and packaging and delivering the qualified magnet according to requirements.

Example one

The neodymium-iron-boron magnet is prepared from commercially available BNP-12 magnetic powder, the specification of the magnet is 14.2 x 12.6 x 3.7mm, and the pressing density is 6.0g/cm ³ Curing at 180 ℃ for 30 minutes, carrying out low-temperature heat treatment on the battery and the magnet after saturation magnetization, wherein the treatment temperature is 80 ℃ and the treatment time is 60 minutes, and testing the thermal demagnetization rate of the obtained magnet;

comparative example 1

Different from the preparation steps of the first embodiment, after electrophoresis and saturation magnetization, the magnet is not subjected to low-temperature heat treatment, the rest is the same, and the obtained magnet is tested for thermal demagnetization rate;

the results of the magnet testing thermal demagnetization rates for the first example and the first comparative example are shown in the following figures:

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example two

The neodymium-iron-boron magnet is prepared from commercially available BNP-6 magnetic powder, the specification of the magnet is 44 x 38 x 16mm, and the pressing density is 6.0g/cm ³ Curing at 180 ℃ for 30 minutes, carrying out low-temperature heat treatment on the battery and the magnet after saturation magnetization, wherein the treatment temperature is 90 ℃ and the treatment time is 240 minutes, and testing the thermal demagnetization rate of the obtained magnet;

comparative example No. two

Different from the preparation steps of the embodiment 2, the magnet is not subjected to low-temperature heat treatment after electrophoresis and saturation magnetization, the rest is the same, and the obtained magnet is tested for the thermal demagnetization rate;

the results of the magnet testing thermal demagnetization rates for example two and comparative example two are shown in the following figures:

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EXAMPLE III

The neodymium-iron-boron magnet is prepared from commercially available BNP-6 magnetic powder, the specification of the magnet is 44 x 38 x 16mm, and the pressing density is 6.0g/cm ³ Curing at 180 ℃ for 30 minutes, carrying out low-temperature heat treatment on the battery and the magnet after saturation magnetization, wherein the treatment temperature is 100 ℃, the treatment time is 60 minutes, and testing the thermal demagnetization rate of the obtained magnet;

comparative example No. three

Different from the preparation steps of the embodiment 3, the magnet is not subjected to low-temperature heat treatment after electrophoresis and saturation magnetization, the rest is the same, and the obtained magnet is tested for the thermal demagnetization rate;

the results of the magnet test thermal demagnetization rate for example three and comparative example three are shown in the following graphs:

example four

The NdFeB magnet is prepared from commercially available BNP-12 magnetic powder, the specification of the magnet is 14.2 multiplied by 12.6 multiplied by 3.7mm, and the pressing density is 6.0g/cm ³ Curing at 180 ℃ for 30 minutes, carrying out low-temperature heat treatment on the battery and the magnet after saturation magnetization, wherein the treatment temperature is 120 ℃, the treatment time is 30 minutes, and testing the thermal demagnetization rate of the obtained magnet;

comparative example No. four

Different from the preparation steps of the embodiment 4, the magnet is not subjected to low-temperature heat treatment after electrophoresis and saturation magnetization, the rest is the same, and the obtained magnet is tested for the thermal demagnetization rate;

the results of the magnet test thermal demagnetization rates for example four and comparative example four are shown in the following figures:

in summary, it can be seen from the above embodiments and comparative examples that the bonded ndfeb magnet with a low thermal demagnetization rate provided by the present invention can reduce the thermal demagnetization rate of the bonded ndfeb magnet to within 3%, even within 1%, compared with the 3-10% thermal demagnetization rate of the conventional magnet, and can meet the requirements for the thermal demagnetization index, and meanwhile, the process is relatively simple, convenient, effective, and has an obvious cost advantage, and is suitable for automated, intelligent, and large-scale preparation.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims (5)

1. The utility model provides a low heat subtracts magnetic rate bonding neodymium iron boron magnetism body which characterized in that, includes the neodymium iron boron magnetism body, the neodymium iron boron magnetism body is made by the neodymium iron boron magnetism powder, the neodymium iron boron magnetism body has low heat and subtracts magnetic rate.

2. A low thermal demagnetization bonded ndfeb magnet as claimed in claim 1 wherein the thermal demagnetization of the ndfeb magnet is less than 3%.

3. A low thermal demagnetization bonded ndfeb magnet as claimed in claim 1 wherein the thermal demagnetization of the ndfeb magnet is less than 1%.

4. The bonded neodymium iron boron magnet with low heat demagnetization rate as claimed in claim 1, wherein the neodymium iron boron magnetic powder is BNP-6 or BNP-8 or BNP-9 or BNP-10 or BNP-11 or BNP-12 or BNP-13.

5. The preparation method of the neodymium-iron-boron magnet based on the claim 1 is characterized by comprising the following steps:

step S1, pulverizing, namely mixing neodymium iron boron magnetic powder with a bonding agent to prepare magnetic rubber powder;

s2, forming, namely forming the magnetic glue powder into a pressed blank through an automatic press;

s3, curing, namely curing the pressed blank by using curing equipment to ensure that the product reaches certain mechanical strength;

s4, performing surface treatment, namely performing anti-corrosion treatment on the surface of the pressed compact to improve the oxidation resistance of the magnet;

s5, magnetizing, namely magnetizing the magnet through a magnetizing machine, a magnetizing coil and a special clamp;

s6, performing heat treatment, namely performing low-temperature heat treatment on the magnetized magnet, wherein the temperature range of the heat treatment is 80-120 ℃, and the time of the heat treatment is 0.5-4 h;

and S7, packaging and delivering, namely inspecting the heat-treated magnet, and packaging and delivering the qualified magnet according to the requirement.

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