KR0128137B1 - Producing method of al-ni-co complex magnetic powder - Google Patents

Abstract

quenching an alnico alloy to be formed a fine crystal quenching powder and pulverizing into fine powder, and thermal annealing in the external magnetic field of 1 - 10KOe in the temperature of 650 - 950deg.C for 2 - 30 minutes, and then performing the thermal annealing in the temperature of 50 - 700deg.C for 1 - 10 hours; performing the surface treatment the fabricated magnetic powder with the silane coupling agent of 0.5 - 2.0 weight% in the reference of the weight of the magnetic powder; and mixing the surface-treated magnetic powder with a thermosetting resin containing a fat carbon ester 5 - 30 weight% in the reference of the weight of the thermosetting resin.

Description

The present invention is a manufacturing method of alnico compound magnetic powder for thermosetting resin magnet

The present invention relates to a method for producing alnico composite magnetic powder for thermosetting resin magnet, and more particularly, to a method for preparing alnico composite magnetic powder for thermosetting resin magnet using rapid cooling method.

Conventional alnico magnetic alloys containing Al, Ni, Co, Cu, Fe or Al, Ni, Co, Cu, Ti, Fe as the main components are generally melt casting methods (Japanese Patent Laid-Open No. 41-9284 and ( 39-24213), but the cutting process is very difficult due to the characteristics of the hard and fragile aluminum magnets. Therefore, the magnets having a small and complicated shape are made of powder metallurgy (Japanese Patent Laid-Open No. 57-24). 207101 and (small) 61-127848). However, powder metallurgy also has limitations in producing magnets of very thin dimensions or complex shapes, and has the disadvantage of being expensive. Therefore, to compensate for these disadvantages, an alnico resin magnet is used in which the alnico magnetic powder is molded into a desired shape using an organic resin (hereinafter referred to as a resin) as a binder.

The alnico resin magnet (or bond magnet) is compression molded using a thermosetting resin such as epoxy resin or phenol resin, or injection molding using a thermoplastic resin such as nylon. It is manufactured by.

Conventionally, alnico-based magnetic powder for resin magnets is prepared by inducing and melting an ingredient of a desired composition to ingot (ingot), and then ingot-treated at 900-1300 ^o C for 30-60 minutes. Continuous cooling in a magnetic field at 650-950 ^° C. After the aging at 500-700 ^o C again, the obtained heat-treated product was prepared by coarsely pulverizing and pulverizing. However, this method is complicated and economical, in particular, because the ingot must not only be solution-treated at 900-1300 ^° C. but also needs to be pulverized and manufactured into fine powder.

Accordingly, an object of the present invention is to provide an alnico-based thermoplastic composite powder production method for resin magnets which is inexpensive and has a simple manufacturing process (that is, does not require ingot production, solution treatment, and ingot grinding process). will be.

According to the present invention, Al-Ni-Co-Cu-Fe or Al-Ni-Co-Cu-Ti-Fe as the main component in the manufacturing method of alnico composite magnetic powder for resin magnets, the alnico alloy is fine and then ground to a fine powder and then quenched by rapid cooling to form a crystalline powder of the type and 650-950 ^o C and a temperature giving an external magnetic field of 1-10KOe from 2-30 minutes in a magnetic field heat treatment at 500-700 ^o C l Aging heat treatment for 10 hours Surface treatment of the prepared magnetic powder with 0.5-2.0% by weight of silane coupling agent based on the weight of the magnetic powder and 5-30 weight of aliphatic carboxylic acid ester in the surface-treated magnetic powder Provided is a method for preparing alnico composite powder for thermosetting resin magnets, characterized in that the composition comprises 1-5% by weight of thermosetting resin containing%.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

According to the method of the present invention, the ingot preparation and solution, which are required in the conventional method, are rapidly cooled by quenching an alnico alloy containing Al-Ni-Co-Cu-Fe or Al-Ni-Co-Cu-Ti-Fe as a main component. Alnico alloy powder can be produced directly without treatment and ingot grinding process.

When the powder is manufactured, by using the rapid cooler disclosed in Korean Patent No. 48371, rapid cooling of the molten alnico alloy in a molten state according to the ejection type melt rotation method may be made into a microcrystalline (1-30um) rapid cooling powder. .

At this time, when the linear velocity of the rotor of the rapid cooler is 6 m / sec or less, the force for discharging the alloy in the molten state is weak, so that it is difficult to obtain powder and the linear velocity may be higher than 40 m / sec. It is preferable to make 6-40 m / sec.

As described above, the powder prepared by quenching is easily pulverized in the form of flakes and very brittle. Therefore, it can be easily prepared to a particle size of less than 250 mesh by a conventional grinding process in an organic solvent such as hexane, acetone, alcohol or the like.

Thereafter, the pulverized quench powder was filled in a vacuum quartz tube and then heat-treated in a magnetic field under an argon or hydrogen atmosphere for 2-30 minutes while loading an external magnetic field of 1-10 KOe at a temperature range of 650-950 ^° C.

By heat treatment in the magnetic field as described above, the amount of the Fe-Co-based precipitate (which exhibits the ferromagnetic property) precipitated in the alnico magnetic alloy material during the heat treatment is increased and grows in a directionally constant arrangement during precipitation.

If the heat treatment for 2 minutes or less in the magnetic field does not completely produce a precipitate, the magnetic properties are lowered. If the heat treatment for 30 minutes or more, the precipitate is coarse and the magnetic properties are lowered.

After the heat treatment, aged at 500-700 ^o C for 1-10 hours. When the temperature is less than 500 ^o C at the time of aging treatment, the effect is not sufficient, and when it is above 700 ^o C, it is preferable that the aging treatment is performed at 500-700 ° C. as the precipitate grows and the magnetic field treatment effect is reduced.

Thereafter, the prepared magnetic powder is surface treated with a coupling agent. By surface treatment, lubricity is imparted to the magnetic powder, dispersibility and molding processability are improved, and magnetic properties and mechanical strength of the resin magnet are improved.

As the coupling agent, a conventional coupling agent may be used, but gamma-amino propyltriethoxy silane, gamma-glycidoxypropyl trimethoxy silane, and gamma- Preference is given to using a silane coupling agent selected from the group consisting of methacryloxypropyl trimethoxy silane.

The coupling agent is added to the magnetic powder at 0.5 to 2.0% by weight based on the weight of the magnetic powder.

This is because when the added amount is 0.5% by weight or less, the effect of treating the coupling agent is insufficient, and when it is 2.0% by weight or more, the unreacted coupling agent is left, resulting in adverse effects such as reducing the residual magnetic flux density.

In the case of surface treatment of the magnetic powder with a sallan-based coupling agent, since the silane coupling agent is liquid, it can be directly mixed as it is, but mixing using a solvent such as alcohol and acetone is preferable since it is uniformly coated on the magnetic powder. Surface treatment is usually carried out at room temperature or below 100 ° C.

Finally, a thermosetting resin containing an aliphatic ester is added to the magnetic powder surface-treated with the coupling agent and mixed to prepare an alnico composite powder for thermosetting resin magnets.

By adding an aliphatic carboxylic acid ester to the thermosetting resin, friction between the magnetic powder and the resin and interaction between the polar groups in the resin are reduced, so that the amount of the magnetic powder is increased to improve the magnetic properties.

As the aliphatic carboxylic acid ester added to the thermosetting resin, ethyl stearate, ethyl oleate, methyl linoleate, and the like are used. When the amount of the thermosetting resin is added in an amount of 5% by weight or less, the effect is insignificant, and 30% by weight or more. In this case, it is preferable to add 5-30% by weight, adversely affecting the magnetic properties.

As the thermosetting resin, a thermosetting resin generally used may be used, and an epoxy resin is generally used.

When the amount of the thermosetting resin containing the aliphatic ester to the surface-treated ejaculate powder is 5% by weight or more based on the weight of the magnetic powder, the amount of the resin is too large and the magnetic properties are reduced. It is preferable to add 1-5% by weight since the strength of the magnet is lowered.

The composite magnetic powder prepared as described above is molded and cured to produce a resin magnet. When the molding is severely damaged by the mold increase the molding pressure not less than the molding pressure is 1ton / cm ^2, the molding pressure is low, it is difficult to maintain the strength, 10ton / cm ² or less, the molding pressure of 1-10ton / cm ² It is preferable to form a molded body by molding, and the molded body is cured by heating at 120-180 ^° C. for 1-4 hours in a vacuum dry oven to prepare a resin magnet. The curing temperature and time set forth above are adjustable in an appropriate range so that the epoxy resin has a completely three-dimensional network.

Hereinafter, embodiments of the present invention will be described in detail.

Example 1

Al, Ni, Co, Cu and Fe ingots are 8% by weight (hereinafter referred to as%). Al-14% Ni-24% Co-3% Cu-51% Fe composition is weighed in an Alnico 5-based composition and completely melted by plasma in an argon (Ar) gas atmosphere, followed by flakes with an ejection melting rotor. ) Quenching powder was prepared and the cooling speed at this time, that is, the linear linear velocity of the cooling rotor was changed to 8.5-32.7 m / sec.

X-ray diffraction analysis and average grain size of the quench powder prepared as described above were measured, and the results are shown in Table 1 below.

As can be seen in Table 1 below, all appeared crystalline tissue.

Each quenched powder prepared as described above was pulverized using an attritor in an alcohol solvent and classified using a sieve specified in ASTM E11 of 60 mesh to have a particle size of 250 micrometers or less. A powder was obtained. These powders were filled in quartz tubes and then 650-900 under argon gas atmosphere. After cooling with load of 7 KOe magnetic field in temperature range, 600 After aging at C for 4 hours to obtain a magnetic powder, 0.5 wt% of γ-aminopropyl triethoxysilane was diluted in ethyl alcohol as a coupling agent. The magnetic powder surface was treated by drying to remove alcohol.

After mixing 97.5% by weight of the magnetic powder surface treated with the coupling agent and 2.5% by weight of epoxy resin containing 20% by weight of ethyl stearate, the mixture was compression-molded at 8 ton / cm 2 and the produced molded product was dried in a vacuum dry oven. Curing treatment with C for 1 hour to prepare a resin magnet. Magnetic properties of these resin magnets were measured and the results are shown in Table 2 below.

Example 2

Al, Ni, Co, Cu, Ti, Fe ingots were weighed with an Alnico 8-based alloy composition having the composition shown in Table 3, followed by complete melting with a plasma arc in an argon gas atmosphere, followed by quenching in a short fiber shape with an ejection melt rotor. Powder was prepared and the cooling speed at this time, that is, the rotation speed of the cooling rotor was 8.51 m / sec.

X-ray diffraction analysis of the quenched powder prepared as described above showed all crystalline structures, and the composition of the alloy dissolved in Table 3 below.

Each quenched powder prepared as described above was pulverized in an alcohol solvent using an attritor and then classified using a sieve defined in ASTM E11 of 60 mesh to obtain a powder having a particle size of 250 μm or less. These powders were charged in a quartz tube and then 780-840 under argon gas atmosphere. After isothermal magnetic field heat treatment for 10 minutes while loading 7 KOe magnetic field at C temperature, 600 Aged at C for 10 hours to obtain magnetic powder. 0.5 wt% of γ-amino propyl triethoxysilane as a coupling agent was diluted in ethyl alcohol, and then impregnated with magnetic powder to stir evenly on the surface of the magnetic powder, followed by drying to remove alcohol. Was surface treated.

97.5% by weight of each magnetic powder surface-treated with the coupling agent and 2.5% by weight of epoxy resin containing 20% by weight of ethyl stearate were mixed, and then the mixture was 8 ton / cm. Molded and molded in a vacuum dry oven Curing treatment with C for 1 hour to prepare a resin magnet. Magnetic properties of these resin magnets were measured and the results are shown in Table 4 below.

As shown in Tables 2 and 4, the thermosetting resin magnets prepared according to the present invention have similar magnetic properties as compared to the thermosetting resin magnets obtained by pulverizing the ingot prepared by the conventional casting method, and do not require solution treatment. And it can be seen that the alnico-based composite powder for thermosetting resin magnets can be manufactured in an inexpensive and simple process due to easy grinding.

Claims (2)

In the method for producing alnico composite magnetic powder for resin magnets, in which Al-Ni-Co-Cu-Fe or Al-Ni-Co-Cu-Ti-Fe is a main component, an alnico alloy is a microcrystalline quenching type. After quenching to form a powder, it was pulverized into fine powder, heat-treated for 2-30 minutes in the magnetic field while loading an external magnetic field of 1-10KOe at a temperature of 650-950 ° C, and aged for 1-10 hours at 50-700 ° C. Step The surface of the prepared magnetic powder with a silane coupling agent of 0.5-2.0% by weight based on the weight of the magnetic powder and 5-30 weight of aliphatic carboxylic acid ester based on the weight of the thermosetting resin on the surface-treated magnetic powder A method for producing an alnico composite powder for thermosetting resin magnets, characterized in that it comprises a 1 to 5% by weight of the thermosetting resin containing% based on the weight of the magnetic powder. The method of claim 1, wherein the silane coupling agent is gamma-aminopropyl triethoxy silane (gamma-aminopropyl triethoxy silane), gamma-glycidoxypropyl trimethoxy silane (gamma-glycidoxypropyl trimethoxy silane) and γ-methacryloxy Characterized in that it is selected from the group consisting of gamma-methacryloxypropyl trimethoxy silane.