Background technology
Dimensional accuracy is high, the form degree of freedom is large, mechanical strength good, be convenient to the advantages such as production in enormous quantities because it has for NdFeB Bonded Magnets, is widely used in the fields such as space flight, traffic, computer, medical treatment.At present, NdFeB Bonded Magnets is mostly isotropic magnet, and the magnetic property of this kind of magnet is general very low, limits its further application & development.Therefore, along with electronic product develops to microminiaturized, complex-shapedization such as light, thin, micro-, little, the anisotropic bonded NdFeB magnet with more high magnetic characteristics is placed high hopes by people.
In order to make anisotropic bonded NdFeB magnet have high magnetic characteristics, the magnetic of magnet inside must be made to align, and therefore anisotropic bonded NdFeB magnet generally needs at magnetic field compacted under.Early stage researchers once attempted the method for preparing anisotropic permanent NdFeB Bonded Magnets adopting room temperature magnetic field dry pressing, if publication number is the hard resin for the production of anisotropic bonded magnet as described in the patent of invention of CN1087744 A and manufacture method thereof: after anisotropic bonded NdFeB magnetic and binding agent mix and blend, adopt the method cracking magnetic of ball milling, then magnetic field is at room temperature carried out dry-pressing formed, although this method can prepare anisotropic bonded NdFeB magnet, but, because under room temperature, the binding agent on magnetic surface is solid-state, frictional force between magnetic is very large, cause magnetic orientation difficulty under magnetic field, therefore the anisotropic bonded NdFeB magnet preparing excellent performance is difficult to.Follow-up researcher also been proposed the shaping method of magnetic-field temperature-pressure, the manufacture method of the magnetic anisotropic resin mating-type magnetic body as described in No. 8-31677, Japanese Patent Laid-Open: by anisotropic bonded NdFeB magnetic and binding agent mix and blend, form the magnetic powder particle of binding agent coating, then magnetic powder particle is put into mould to heat, binding agent is made to be in molten condition, finally carry out magnetic field orientating, prepare the anisotropic bonded NdFeB magnet of high-orientation, to this method solve under room temperature frictional force between magnetic powder particle large, the problem of orientation difficulty, but, due to the binding agent on magnetic surface under heated condition softening after easily stick on the mould wall, also there is the problem of reinforced difficulty in the method.For this difficult problem, publication number is the method that the patent of invention of CN1087744 A proposes multistep shaping manufacture anisotropic bonded NdFeB magnet: the magnetic after hybrid adhesive is first carried out cold moudling, prepare the preformed compact that density is lower, then by preformed compact warm compaction molding under magnetic field, final curing obtains anisotropic bonded NdFeB magnet, although the problem of this method reinforced difficulty under solving anisotropic magnet powder Warm status, but undesirably increase technology difficulty, reduce production efficiency.Magnetic field Wet-pressing molding technique is as a kind of effective technique preparing anisotropy magnet, be widely used in the production of anisotropy ferrite sintered body, as the publication number patent of invention that is CN101354939A discloses a kind of preparation method of superfine permanent ferrite forming slurry, after this slurry is carried out magnetic field Wet-pressing molding, carry out sintering processes, high performance ferrite permanent-magnet can be prepared, but, the method but not anisotropic bonded NdFeB magnet shaping on be applied.
Summary of the invention
The present invention is directed to existing anisotropic bonded NdFeB magnet complicated process of preparation, deficiency that production efficiency is low, a kind of preparation method of room temperature Wet-pressing molding anisotropic bonded NdFeB magnet is provided.
The object of the invention is to be implemented by the following technical programs:
A kind of preparation method of room temperature Wet-pressing molding anisotropic bonded NdFeB magnet, comprise magnetic surface-modification processes, binding agent and magnetic mixed processes, magnetic slurry preparation section, magnetic field compression molding operation and the several operation of vacuum solidification operation, wherein, the molding mode adopted in described magnetic field compression molding operation is Wet-pressing molding under room temperature.
Inventor finds, when adopting Wet-pressing molding technique, owing to there is the liquid barrier film of one deck between magnetic powder particle, frictional force when significantly reducing orientation between magnetic powder particle, thus be conducive to the degree of orientation improving magnetic, make magnet have excellent magnetic property, and, because Wet-pressing molding technique is at room temperature carried out, the situation occurring reinforced difficulty in warm compaction process can be avoided.
Inventor also finds, when carrying out Wet-pressing molding step, the solvent in slurry can be extruded magnet under the effect of press power, does not affect the final densities of magnet.
As preferably, according to the preparation method of a kind of room temperature Wet-pressing molding anisotropic bonded NdFeB magnet of the present invention, wherein, the magnetic field intensity adopted in described magnetic field compression molding operation is 1-2T, and pressure is 3-9t/m
2.So doing is to improve the degree of orientation of magnetic and the density of magnet in magnet, thus improves the magnetic property of magnet.
As preferably, according to the preparation method of a kind of room temperature Wet-pressing molding anisotropic bonded NdFeB magnet of the present invention, wherein, add solvent in described magnetic slurry preparation section, described solvent is made up of one or several in methyl alcohol, ethanol, water, phosphoric acid solution or mineral oil.Amount of solvent controls in about 50% of NdFeB magnetic quality.
As preferably, according to the preparation method of a kind of room temperature Wet-pressing molding anisotropic bonded NdFeB magnet of the present invention, wherein, add surfactant in described magnetic slurry preparation section, described surfactant is made up of one or several in neopelex, polysorbate, fatty glyceride, sodium pyrophosphate, sodium phosphate trimer or sodium metaphosphate.So doing is in order to agglomerated magnetic powder particle is together scattered, and suspends in a solvent, forms magnetic slurry.The consumption of surfactant is 0.1% ~ 1% of NdFeB magnetic quality, and consumption cannot make magnetic be distributed in solvent very little, forms uniform magnetic slurry; Consumption is too many, and then effect is saturated, and non-magnetic phase increases the magnetic property affecting magnet simultaneously.
As preferably, according to the preparation method of a kind of room temperature Wet-pressing molding anisotropic bonded NdFeB magnet of the present invention, wherein, add lubricant in described magnetic slurry preparation section, described lubricant is cured by zinc stearate, calcium stearate, PE, one or several in ethylene bis stearamide or pentaerythritol stearate form.So doing is frictional resistance in order to reduce during magnetic orientation, improves the degree of orientation.The addition of lubricant is generally 0.1% ~ 1% of NdFeB magnetic quality, on the weak side lower than 0.1% lubricant effect, reduces the magnetic degree of orientation, saturated higher than 1% lubricant effect, increases non-magnetic phase content and reduces magnet magnetic property.
As preferably, according to the preparation method of a kind of room temperature Wet-pressing molding anisotropic bonded NdFeB magnet of the present invention, wherein, in described magnetic slurry preparation section, add solvent, and ball milling is carried out to magnetic and solvent, the abrading-ball density adopted during ball milling is 2-5g/cm
3, as glass marble, aluminium ball, alumina balls.Ball milling can make coherent magnetic generation cracking in binding agent and magnetic mixed processes, forms single anisotropic magnetic powder particles, can further improve the degree of orientation of magnetic in magnet.The too low abrading-ball of density cannot make magnetic powder particle cracking, and the too high abrading-ball of density can cause magnetic tissue to be destroyed, and reduces magnetic property.
Compared with prior art, the present invention has the following advantages:
In the present invention, the molding procedure of magnet is at room temperature carried out, therefore there is the advantage that moulding process is simple, production efficiency is high, energy consumption is low, and owing to being Wet-pressing molding, one deck fluid film is there is between magnetic powder particle, effectively can reduce frictional resistance during magnetic powder particle orientation, improve the magnetic property of magnet.
Embodiment
Below in conjunction with embodiment, further illustrate content of the present invention.Should be appreciated that enforcement of the present invention is not limited to the following examples, any pro forma accommodation make the present invention and/or change all will fall into scope.
In the present invention, if not refer in particular to, all parts, percentage are unit of weight, and all equipment and raw material etc. all can be buied from market or the industry is conventional.Method in following embodiment, if no special instructions, is the conventional method of this area.
embodiment 1:
The anisotropic bonded NdFeB magnetic that the present embodiment adopts HDDR technique to prepare is as raw material magnetic, and its maximum magnetic energy product is (BH) max=288kJ/m
3, HCJ Hcj=1040kA/m.
A preparation method for room temperature Wet-pressing molding anisotropic bonded NdFeB magnet, comprising:
The silane coupler (commercially available KH550) of pulp furnish: 0.1wt%, the anisotropic bonded NdFeB magnetic of 99.6wt%, the epoxy adhesive of 0.3wt%.
(1), magnetic surface-modification processes: the silane coupler (commercially available KH550) of 0.1wt% is dissolved with ethanol, then add the anisotropic bonded NdFeB magnetic of 99.6wt% and mix, then dry at 40 ~ 80 DEG C, obtain the anisotropic bonded NdFeB magnetic of surface modification.
(2), binding agent and magnetic mixed processes: by the epoxy adhesive acetone solution of 0.3wt%, add above-mentioned in the anisotropic bonded NdFeB magnetic of surface modification, and mix, dry.
(3), magnetic slurry preparation section: magnetic-epoxy resin composition is placed in planetary ball mill, add neopelex (0.1% of magnetic quality), ethanol (50% of magnetic quality) and calcium stearate (0.1% of magnetic quality), carry out mechanical ball milling, form magnetic slurry, wherein, abrading-ball adopts density to be 3.97g/cm
3alumina balls.
(4), magnetic field compression molding operation: magnetic slurry is injected mould, is pressed into the magnet standard specimen of Φ 10mm × 10mm under room temperature, compacting magnetic field 1.5T, pressing pressure 9t/cm
2.
(5), vacuum solidification operation: by magnet standard specimen vacuum solidification 3h at 140 DEG C.
The magnet standard specimen obtained by the present embodiment detects, and magnetic energy product (BH) max reaches 172kJ/m
3.
embodiment 2
Other operations of the present embodiment are with embodiment 1, and difference is: the magnetic field adopted is 1T.
The magnet standard specimen obtained by the present embodiment detects, and magnetic energy product (BH) max reaches 155.6kJ/m
3.
embodiment 3
Other operations of the present embodiment are with embodiment 1, and difference is: the magnetic field adopted is 2T.
The magnet standard specimen obtained by the present embodiment detects, and magnetic energy product (BH) max reaches 173.6kJ/m
3.
embodiment 4
Other operations of the present embodiment are with embodiment 1, and difference is: the pressing pressure adopted is 3t/cm
2.
The magnet standard specimen obtained by the present embodiment detects, and magnetic energy product (BH) max reaches 91kJ/m
3.
embodiment 5
Other operations of the present embodiment are with embodiment 1, and difference is: the pressing pressure adopted is 5t/cm
2.
The magnet standard specimen obtained by the present embodiment detects, and magnetic energy product (BH) max reaches 133.6kJ/m
3.
embodiment 6
Other operations of the present embodiment are with embodiment 1, and difference is: the pressing pressure adopted is 9t/cm
2.
The magnet standard specimen obtained by the present embodiment detects, and magnetic energy product (BH) max reaches 142kJ/m
3.
embodiment 7
Other operations of the present embodiment are with embodiment 1, and difference is: the consumption of neopelex is 1% of magnetic quality.
The magnet standard specimen obtained by the present embodiment detects, and magnetic energy product (BH) max reaches 154kJ/m
3.
embodiment 8
Other operations of the present embodiment are with embodiment 1, and difference is: calcium stearate consumption is 1% of magnetic quality.
The magnet standard specimen obtained by the present embodiment detects, and magnetic energy product (BH) max reaches 165kJ/m
3.
comparative example 1
Other operations of the present embodiment are with embodiment 1, and difference is: do not carry out mechanical ball grinder sequence.
The magnet standard specimen obtained by the present embodiment detects, and magnetic energy product (BH) max reaches 112.3kJ/m
3.
comparative example 2
Other operations of the present embodiment are with embodiment 1, and difference is: to adopt abrading-ball to be density be 7.5 g/cm
3stainless steel ball.
The magnet standard specimen obtained by the present embodiment detects, and magnetic energy product (BH) max reaches 150.2kJ/m
3.
comparative example 3
Other operations of the present embodiment are with embodiment 1, and difference is: do not add surfactant.
The magnet standard specimen obtained by the present embodiment detects, and magnetic energy product (BH) max reaches 132.6kJ/m
3.
comparative example 4
The anisotropic magnet powder that this comparative example adopts is with embodiment 1, and processing step is as follows:
1, the coupling agent ethanol of 0.1wt% is dissolved, then add the anisotropic bonded NdFeB magnetic of 99.6wt% and mix, then dry at 40 ~ 80 DEG C, obtain the anisotropic bonded NdFeB magnetic of surface modification.
2, by the epoxy adhesive acetone solution of 0.3wt%, add above-mentioned in the anisotropic bonded NdFeB magnetic of surface modification, and mix, dry.
3, binding agent is put into mould, under room temperature, magnetic field is dry-pressing formed, magnetic field 1.5T, pressure 9t/cm
2.
4, by magnet standard specimen vacuum solidification 3h at 140 DEG C.
The magnet standard specimen obtained by this comparative example detects, and magnetic energy product (BH) max is 78kJ/m
3.
comparative example 5
Other operations of this comparative example are with comparative example 4, and difference is: be shaped to warm compaction molding, and forming temperature is 130 DEG C.
The magnet standard specimen obtained by this comparative example detects, and magnetic energy product (BH) max is 178kJ/m
3, magnetic property is a little more than the anisotropic bonded NdFeB magnet of room temperature Wet-pressing molding, but complex manufacturing, and production efficiency is low.
Above preferred embodiment, just for instruction and explanation of content of the present invention, does not form the restriction to content of the present invention.Although inventor enumerates in more detail to invention has been, but, the content that those skilled in the art discloses according to summary of the invention part and embodiment, various amendment can be made or/and it is obvious for supplementing or adopting similar mode to substitute to described specific embodiment, and technique effect of the present invention can be realized, therefore, repeat no longer one by one herein.The term occurred in the present invention, for the elaboration of technical solution of the present invention and understanding, is not construed as limiting the invention.