JPH08264360A - Resin-bonded magnet manufacturing method and resin-bonded magnet - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a method for manufacturing a resin-bonded magnet in which the quality variation is small in a short time or in a small number of steps. [Structure] Magnetic powder as a raw material powder, polyamide resin,
Or polyimide resin, epoxy resin, polyethylene,
Polyphenylene sulfide, ABS resin, amino resin,
A manufacturing method for manufacturing a resin-bonded magnet using a discharge plasma sintering method using a material to which any one of a phenol resin, polyethylene terephthalate and polycarbonate is added.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-bonded magnet manufacturing method and a resin-bonded magnet.

[0002]

2. Description of the Related Art Demand for resin-bonded magnets currently in production is growing, centering on small motors used in office automation equipment, cameras, home appliances, etc. Shows. For resin-bonded magnets
By a compression molding method using a thermosetting resin as disclosed in Japanese Patent No. 18559 and Japanese Patent Publication No. 55-331.
No. 73 or Japanese Examined Patent Publication No. 58-53491, and the more recent magnets manufactured by the injection molding method, and more recently, Japanese Unexamined Patent Publication No. 61-121307 or Japanese Unexamined Patent Publication No. 62-20.
There is an extruded magnet as disclosed in Japanese Patent No. 8612.

At present, the largest amount of production is a magnet using a thermosetting resin. This is because a high performance magnet can be obtained because the magnet can be molded with a small amount of resin. On the other hand, injection-molded magnets and extruded magnets using thermoplastic resins can have magnets with complicated shapes or pipe shapes, but a certain degree of fluidity is required for the mixture of resin and magnetic powder during molding. The amount of resin to be added is larger than that of the thermosetting resin, and in actuality, it does not reach the thermosetting resin type in terms of performance.

Further, in order to mold a magnet by a compression molding method using a thermoplastic resin, it is necessary to put resin and magnetic powder into a mold and pressurize while heating, and in the prior art, hot pressing corresponds to this.

[0005]

However, the prior art has the following problems.

[0006] In the hot press, it takes time to heat up, mold and cool, which lowers the productivity, and since the heating is conducted by heat transfer, a temperature difference occurs inside the molded body during molding, which causes a large density difference depending on the location. It is a cause and causes a variation in performance. Further, when a thermosetting resin is used, it is necessary to heat the resin after molding to cure the resin, and in order to obtain a product, at least two steps of molding and baking are required. Further, the molded product before curing the resin has weak mechanical strength and is liable to be deformed or chipped, so that it is necessary to handle it with sufficient care.

The present invention relates to a method for producing a resin-bonded magnet using a thermoplastic resin or a thermosetting resin as magnetic powder and a resin-bonded magnet, and an object of the invention is to solve the above problems. In addition, a thermoplastic resin or thermosetting resin was added to the magnetic powder to produce a resin-bonded magnet that is efficient and has little quality variation by manufacturing by the spark plasma sintering method. The present invention provides a resin-bonded magnet manufactured by the manufacturing method.

[0008]

The present invention is characterized in that a thermoplastic resin or a thermosetting resin is added to magnetic powder and the magnetic powder is manufactured by a spark plasma sintering method.

The discharge plasma sintering method is a method also called plasma activated sintering method, in which a pulsed electric current is directly applied to the metal powder under pressure to cause spark discharge and plasma generation between the particles to cause powder generation. It is what is sintered. FIG. 1 shows the basic configuration. The basic structure consists of a press for molding, a power supply for energizing, and a molding die.
This method was developed in the 1960s and has been applied to the development of intermetallic compounds, functionally graded materials and the like. In the discharge plasma sintering method, since the generation of discharge plasma is used as energy for sintering, a temperature difference hardly occurs depending on a place, and a homogeneous and high-quality sintered body can be obtained. Further, the sintering rate is also higher than that of the conventional sintering method. Another feature is that it is possible to bond ceramics and metal, which has been considered difficult until now, and to manufacture a porous sintered body.

The present invention applies the discharge plasma sintering method as a heating means for inducing a melting or curing reaction of a resin as a binder added to magnetic powder, instead of the usual sintering of metal or ceramics. is there.

After adding a thermoplastic resin or a thermosetting resin to the magnetic powder and filling the mold, a pulse current is applied while pressure is applied according to the principle of discharge plasma sintering, and the powder generates heat by heating to heat the surrounding resin. To do. If the resin is a thermoplastic resin, it melts and enters into the voids between the magnetic powders by the pressure applied at the same time, functions as a liquid lubricant, and compacts the compact. After densifying to some extent, the mold is cooled and the molded body is taken out. This makes it possible to obtain a high-performance resin-bonded magnet having a higher content of magnetic powder than that obtained by injection molding or extrusion molding while using a thermoplastic resin as a binder. If the resin is a thermosetting resin such as an epoxy resin, the resin is heated in the same manner, and once the resin is heated, the resin softens or the viscosity decreases. At this time, densification of the molded body occurs due to pressurization, and then a curing reaction occurs and cures as the temperature rises. After curing, it is cooled and the molded product is taken out. As a result, what has heretofore been two steps of molding and baking for curing the resin can be performed in one step.

In the twelfth to fourteenth aspects, the amount of the resin added is set to 0.5 to 10% by weight, as will be described in the examples, and the superiority of the magnetic properties of the product of the present invention is clearly recognized in comparison with the conventional method. This is because it is a range.

[0013]

EXAMPLES Examples will be described below.

(Example 1) Nd, Fe as raw material powder,
Magnetic powder containing B and Co as the main components by the quenching ribbon method was used. Magnetic powder with a vibrating ball mill has an average particle size of about 36 μm.
After pulverizing into particles, the particles having a size of 90 μm or more were removed by a sieve. Nylon 12 having an average particle size of 20 μm was added to the obtained powder in an amount of 1.0 and 2.0 wt%, and a total weight of 5 kg was mixed with a high-speed flow type mixer (6500 RPM) having a volume of 15 l for 10 times.
Mix for minutes. 45 g of the obtained powder was filled in a pellet molding die having an outer diameter of 20 mm and set in a discharge plasma sintering apparatus. The sintering conditions are a temperature rising rate of 80 degrees / minute, a sintering temperature (holding temperature) of 230 ° C, a holding time of 3 minutes, and a cooling temperature of 60 ° C.
/ Min, pressing force 650 kgf / cm2, current value 1000
It was set to A to 1500A.

After sintering, a cylindrical molded body having an outer diameter of 20 mm and a height of about 30 mm was taken out, divided into 5 equal parts in the height direction, and the respective densities were measured by the Archimedes method. For comparison, a compression-molded magnet having the same shape of nylon 12 as a binder was prepared by hot pressing and the same measurement was performed (nylon 12 was used in the form of powder having an average particle size of 20 μm or less, and the addition amount was Was 1.0, 2.0 wt%, heating was 50 ° C./minute, holding temperature was 230 ° C., molding holding time was 3 minutes, cooling rate was 30 ° C./minute, molding pressure was 650 kgf /
cm2).

The results are shown in FIG.

It can be seen from FIG. 2 that the present invention can provide a uniform resin-bonded magnet having a small density difference depending on the location.

(Example 2) Nd, Fe as raw material powder,
Magnetic powder containing B and Co as the main components by the quenching ribbon method was used. Magnetic powder with a vibrating ball mill has an average particle size of about 36 μm.
After pulverizing into particles, the particles having a size of 90 μm or more were removed by a sieve. 1.0 and 2.0 wt% of a polyimide resin having an average particle diameter of 20 μm was added to the obtained powder, and a total weight of 5 kg was mixed with a high-speed flow type mixer (6500 RPM) having a volume of 15 l.
Mix for 0 minutes. 45 g of the obtained powder was filled in a pellet molding die having an outer diameter of 20 mm and set in a discharge plasma sintering apparatus. The sintering conditions are a temperature rising rate of 80 degrees / minute, a sintering temperature (holding temperature) of 270 ° C., a holding time of 5 minutes, and a cooling temperature of 60 ° C.
/ Min, pressing force 650 kgf / cm2, current value 1000
It was set to A to 1500A.

After sintering, a cylindrical molded body having an outer diameter of 20 mm and a height of about 30 mm was taken out, divided into 5 equal parts in the height direction, and the respective densities were measured by the Archimedes method. For comparison, a compression-molded magnet having the same shape of a polyimide resin as a binder was prepared by hot pressing and the same measurement was carried out (a polyimide resin powder having an average particle size of 20 μm or less was used, and the addition amount was Was 1.0, 2.0 wt%, heating was 50 ° C./min, holding temperature was 270 ° C., molding holding time was 5 minutes, cooling rate was 30 ° C./min, molding pressure was 650 k.
gf / cm2).

The results are shown in FIG.

It can be seen from FIG. 3 that the present invention can provide a uniform resin-bonded magnet having a small density difference depending on the location.

Example 3 As a raw material powder, a magnetic powder prepared by crushing an alloy containing Sm and Co as main components and prepared by a casting method was used. The magnetic powder is finally crushed with a vibrating ball mill to an average particle size of about 36 μm and then sieved to 90 μm.
Items over m were removed. The obtained powder has an average particle size of 2
1.0 and 2.0 wt% of 0 μm epoxy resin powder was added, and the powder having a total weight of 5 kg was mixed for 10 minutes by a high-speed flow type mixer (6500 RPM) having a volume of 15 l. 45 g of the obtained powder was filled in a pellet molding die having an outer diameter of 20 mm and set in a discharge plasma sintering apparatus. The sintering conditions are a temperature rising rate of 80 degrees / minute, a sintering temperature (holding temperature) of 230 ° C., a holding time of 3 minutes, a cooling temperature of 60 ° C./minute, and a pressing force of 650 kgf.
/ Cm2, and the current value was 1000A to 1500A.

After sintering, a cylindrical molded body having an outer diameter of 20 mm and a height of about 30 mm was taken out, divided into 5 equal parts in the height direction, and the respective densities were measured by the Archimedes method. For comparison, a compression-molded magnet having an epoxy resin of the same shape as a binder was prepared and the same measurement was performed (the epoxy resin used was a powder having an average particle size of 20 μm or less, and the addition amount was 1.
Molding pressure of 650 kgf / cm, with 0, 2.0 wt%
After molding at 2, the resin was cured by baking at 150 ° C. for 1 hour).

The results are shown in FIG.

It can be seen from FIG. 4 that the present invention can provide a uniform resin-bonded magnet with a small density difference depending on the location.

Example 4 As a raw material powder, a magnetic powder prepared by crushing an alloy containing Sm and Co as main components and prepared by a casting method was used. The magnetic powder is finally crushed with a vibrating ball mill to an average particle size of about 36 μm and then sieved to 90 μm.
Items over m were removed. The obtained powder has an average particle size of 2
1.0 and 2.0 wt% of 0 μm polyethylene powder was added, and the powder having a total weight of 5 kg was mixed for 10 minutes by a high-speed flow type mixer (6500 RPM) having a volume of 15 l. 45 g of the obtained powder was filled in a pellet molding die having an outer diameter of 20 mm and set in a discharge plasma sintering apparatus. The sintering conditions are a heating rate of 80 degrees / minute, a sintering temperature (holding temperature) of 120 ° C., a holding time of 3 minutes, a cooling temperature of 60 ° C./minute, and a pressing force of 650 kgf.
/ Cm2, and the current value was 1000A to 1500A.

After sintering, a cylindrical molded body having an outer diameter of 20 mm and a height of about 30 mm was taken out, divided into 5 equal parts in the height direction, and the respective densities were measured by the Archimedes method. For comparison, a compression-molded magnet using polyethylene of the same shape as a binder was prepared and the same measurement was performed (polyethylene powder having an average particle size of 20 μm or less was used, and the addition amount was 1.
0, 2.0 wt% and heating rate is 50 ° C /
Min, holding temperature 120 ° C, molding holding time 5 minutes, cooling rate 3
The molding pressure was 0 ° C./min and the molding pressure was 650 kgf / cm 2.

The results are shown in FIG.

It can be seen from FIG. 5 that the present invention can provide a uniform resin-bonded magnet having a small density difference depending on the location.

Example 5 As a raw material powder, a magnetic powder prepared by crushing an alloy containing Sm and Co as main components and prepared by a casting method was used. The magnetic powder is finally crushed with a vibrating ball mill to an average particle size of about 36 μm and then sieved to 90 μm.
Items over m were removed. The obtained powder has an average particle size of 2
0 .mu.m polyphenylene sulfide powder 1.0, 2.
0 wt% was added, and a powder having a total weight of 5 kg was mixed for 10 minutes by a high-speed flow type mixer (6500 RPM) having a volume of 15 l. 45 g of the obtained powder was filled in a pellet molding die having an outer diameter of 20 mm and set in a discharge plasma sintering apparatus.
Sintering conditions are heating rate of 80 degrees / minute, sintering temperature (holding temperature)
350 ° C., holding time 3 minutes, cooling temperature 60 ° C./minute, pressure 650 kgf / cm 2, current value 1000 A to 1500 A
And

After sintering, a cylindrical molded body having an outer diameter of 20 mm and a height of about 30 mm was taken out, divided into 5 equal parts in the height direction, and the respective densities were measured by the Archimedes method. For comparison, a compression-molded magnet having the same shape of polyphenylene sulfide as a binder was prepared and the same measurement was conducted (polyphenylene sulfide was used in the form of powder having an average particle size of 20 μm or less, and the addition amount was 1. The heating rate was 50 ° C./minute, the holding temperature was 350 ° C., the molding holding time was 8 minutes, the cooling rate was 30 ° C./minute, and the molding pressure was 650 k.
gf / cm2).

The results are shown in FIG.

It can be seen from FIG. 6 that the present invention can provide a uniform resin-bonded magnet with a small density difference depending on the location.

Example 6 Nd, Fe as raw material powder,
Magnetic powder containing B and Co as the main components by the quenching ribbon method was used. Magnetic powder with a vibrating ball mill has an average particle size of about 36 μm.
After pulverizing into particles, the particles having a size of 90 μm or more were removed by a sieve. To the obtained powder, 1.0 and 2.0 wt% of ABS resin having an average particle diameter of 20 μm was added, and a total weight of 5 kg was mixed with a high-speed flow type mixer (6500 RPM) having a volume of 15 l for 10 times.
Mix for minutes. 45 g of the obtained powder was filled in a pellet molding die having an outer diameter of 20 mm and set in a discharge plasma sintering apparatus. The sintering conditions are a temperature rising rate of 80 degrees / minute, a sintering temperature (holding temperature) of 130 ° C, a holding time of 3 minutes, and a cooling temperature of 60 ° C.
/ Min, pressing force 650 kgf / cm2, current value 1000
It was set to A to 1500A.

After sintering, a cylindrical molded body having an outer diameter of 20 mm and a height of about 30 mm was taken out, divided into 5 equal parts in the height direction, and the respective densities were measured by the Archimedes method. For comparison, a compression-molded magnet having the same shape of ABS resin as a binder was prepared by hot pressing and the same measurement was performed (AB
Use the S resin in powder form with an average particle size of 20 μm or less,
The addition amount was 1.0 and 2.0 wt%, and the heating rate was 50 ° C./min, the holding temperature was 130 ° C., and the molding holding time was 3
Min, cooling rate 30 ° C / min, molding pressure 650kgf / c
m2).

The results are shown in FIG.

It can be seen from FIG. 7 that the present invention makes it possible to obtain a uniform resin-bonded magnet having a small density difference depending on the location.

Example 7 Nd, Fe as raw material powder,
Magnetic powder containing B and Co as the main components by the quenching ribbon method was used. Magnetic powder with a vibrating ball mill has an average particle size of about 36 μm.
After pulverizing into particles, the particles having a size of 90 μm or more were removed by a sieve. 1.0 and 2.0 wt% of an amino resin having an average particle size of 20 μm was added to the obtained powder, and a powder having a total weight of 5 kg was mixed with a high-speed flow type mixer (6500 RPM) having a volume of 15 l for 10 times.
Mix for minutes. 45 g of the obtained powder was filled in a pellet molding die having an outer diameter of 20 mm and set in a discharge plasma sintering apparatus. The sintering conditions are a temperature rising rate of 80 degrees / minute, a sintering temperature (holding temperature) of 240 ° C, a holding time of 5 minutes, and a cooling temperature of 60 ° C.
/ Min, pressing force 650 kgf / cm2, current value 1000
It was set to A to 1500A.

After sintering, a cylindrical molded body having an outer diameter of 20 mm and a height of about 30 mm was taken out, divided into 5 equal parts in the height direction, and the respective densities were measured by the Archimedes method. For comparison, a compression-molded magnet having the same shape of an amino resin as a binder was prepared by hot pressing and the same measurement was performed (the amino resin used was a powder having an average particle size of 20 μm or less,
The addition amount was 1.0 and 2.0 wt%, and the heating rate was 50 ° C./min, the holding temperature was 240 ° C., and the molding holding time was 20.
Min, cooling rate 30 ° C / min, molding pressure 650kgf / c
m2).

The results are shown in FIG.

It can be seen from FIG. 8 that the present invention makes it possible to obtain a uniform resin-bonded magnet having a small density difference depending on the location.

Example 8 As the raw material powder, a magnetic powder prepared by crushing an alloy containing Sm and Co as main components and prepared by a casting method was used. The magnetic powder is finally crushed with a vibrating ball mill to an average particle size of about 36 μm and then sieved to 90 μm.
Items over m were removed. The obtained powder has an average particle size of 2
1.0 and 2.0 wt% of 0 μm phenol resin powder was added, and the powder having a total weight of 5 kg was mixed for 10 minutes by a high-speed fluid type mixer (6500 RPM) having a volume of 15 l. 45 g of the obtained powder was filled in a pellet molding die having an outer diameter of 20 mm and set in a discharge plasma sintering apparatus. The sintering conditions are a heating rate of 80 degrees / minute, a sintering temperature (holding temperature) of 250 ° C., a holding time of 3 minutes, a cooling temperature of 60 ° C./minute, and a pressing force of 650 kgf.
/ Cm2, and the current value was 1000A to 1500A.

After sintering, a cylindrical molded body having an outer diameter of 20 mm and a height of about 30 mm was taken out, divided into 5 equal parts in the height direction, and the respective densities were measured by the Archimedes method. For comparison, a compression-molded magnet having the same shape of a phenol resin as a binder was prepared and the same measurement was performed (the phenol resin used was a powder having an average particle size of 20 μm or less, and the addition amount was 1. Molding pressure 650 kgf /
After molding at cm 2, the resin was cured by firing at 250 ° C for 1 hour).

The results are shown in FIG.

It can be seen from FIG. 9 that the present invention can provide a uniform resin-bonded magnet having a small density difference depending on the location.

(Example 9) As a raw material powder, a magnetic powder prepared by crushing an alloy containing Sm and Co as main components and prepared by a casting method was used. The magnetic powder is finally crushed with a vibrating ball mill to an average particle size of about 36 μm and then sieved to 90 μm.
Items over m were removed. The obtained powder has an average particle size of 2
1.0 μm of 0 μm polyethylene terephthalate powder,
2.0 wt% was added, and the total weight of the powder was 5 kg.
The mixture was mixed for 10 minutes using the high speed fluid mixer (6500 RPM). 45 g of the obtained powder was filled in a pellet molding die having an outer diameter of 20 mm and set in a discharge plasma sintering apparatus. The sintering conditions are a temperature rising rate of 80 degrees / minute, a sintering temperature (holding temperature) of 130 ° C., a holding time of 3 minutes, a cooling temperature of 60 ° C./minute, a pressing force of 650 kgf / cm 2, and a current value of 1000 A to 150.
It was set to 0A.

After sintering, a cylindrical molded body having an outer diameter of 20 mm and a height of about 30 mm was taken out, divided into 5 equal parts in the height direction, and the respective densities were measured by the Archimedes method. For comparison, a compression-molded magnet having the same shape of polyethylene terephthalate as a binder was prepared and the same measurement was performed (polyethylene terephthalate was used in the form of powder having an average particle size of 20 μm or less, and the addition amount was 1. 0, 2.0 wt%,
The heating rate is 50 ° C./minute, the holding temperature is 130 ° C., the molding holding time is 5 minutes, the cooling rate is 30 ° C./minute, and the molding pressure is 65 minutes.
0 kgf / cm2).

The results are shown in FIG.

It can be seen from FIG. 10 that the present invention can provide a uniform resin-bonded magnet having a small density difference depending on the location.

(Example 10) Sm and Co as raw material powders
A magnetic powder prepared by crushing an alloy containing as a main component and prepared by a casting method was used. The magnetic powder is finally crushed with a vibrating ball mill to an average particle size of about 36 μm and then sieved to 90
Those having a size of μm or more were removed. 1.0, 2.0 wt. Of polycarbonate powder having an average particle size of 20 μm is added to the obtained powder.
%, And the powder having a total weight of 5 kg was mixed for 10 minutes by a high-speed flow type mixer (6500 RPM) having a volume of 15 l. 45 g of the obtained powder was filled in a pellet molding die having an outer diameter of 20 mm and set in a discharge plasma sintering apparatus. The sintering conditions are a temperature rising rate of 80 degrees / minute and a sintering temperature (holding temperature) of 180.
℃, holding time 3 minutes, cooling temperature 60 ℃ / min, pressure 650
The kgf / cm2 and the current value were 1000A to 1500A.

After sintering, a cylindrical molded body having an outer diameter of 20 mm and a height of about 30 mm was taken out, divided into 5 equal parts in the height direction, and the respective densities were measured by the Archimedes method. For comparison, a compression-molded magnet having a polycarbonate of the same shape as a binder was prepared and the same measurement was performed (the polycarbonate is a powder having an average particle size of 20 μm or less, and the addition amount is 1.0, 2.0 wt% and heating rate is 5
0 ° C./minute, holding temperature 180 ° C., molding holding time 5 minutes, cooling rate 30 ° C./minute, molding pressure 650 kgf / cm 2).

The results are shown in FIG.

It can be seen from FIG. 12 that the present invention can provide a uniform resin-bonded magnet having a small density difference depending on the location.

(Example 11) Nd, F as raw material powder
A magnetic powder containing e, B, and Co as the main components by the quenching ribbon method was used. Magnetic powder with a vibrating ball mill has an average particle size of about 36
After pulverizing to a size of μm, the particles having a size of 90 μm or more were removed by a sieve. Nylon 6 with an average particle size of 20 μm was added to the obtained powder.
Was added at intervals of 0.2 wt% in the range of 0.3 to 12 wt%, and the powder having a total weight of 5 kg was mixed for 10 minutes by a high-speed flow type mixer (6500 RPM) having a volume of 15 l. 15 g of the obtained powder was filled in a pellet molding die having an outer diameter of 20 mm and set in a discharge plasma sintering apparatus. The sintering conditions are a heating rate of 80 degrees / minute, a sintering temperature (holding temperature) of 230 ° C., a holding time of 3 minutes and 10 minutes, a cooling temperature of 60 ° C./minute, and a pressing force of 65.
The current value was 0 kgf / cm2 and the current value was 1000A to 1500A.

After sintering, a cylindrical molded body having an outer diameter of 20 mm and a height of about 10 mm was taken out, and its magnetic performance was measured. still,
For comparison, a compression-molded magnet having the same shape of nylon 6 as a binder was prepared by hot pressing and the same measurement was performed (nylon 12 was used in the form of powder having an average particle size of 20 μm or less, and the addition amount was 1 The heating rate was 50 ° C / minute, the holding temperature was 230 ° C, the molding holding time was 3 minutes and 10 minutes, the cooling rate was 30 ° C / minute, and the molding pressure was 6%.
50 kgf / cm2).

The results are shown in FIG.

From FIG. 12, the product of the present invention has a retention time of 3
The performance is saturated in minutes, but the retention time is 10 in the conventional method.
It can be seen that the product of the present invention cannot be caught up unless it is understood.
In terms of performance, it can be seen that when the holding time is 3 minutes, the product of the present invention is superior when the amount of nylon 12 added is in the range of 0.5 to 10 wt%.

(Example 12) Nd, F as raw material powder
A magnetic powder containing e, B, and Co as the main components by the quenching ribbon method was used. Magnetic powder with a vibrating ball mill has an average particle size of about 36
After pulverizing to a size of μm, the particles having a size of 90 μm or more were removed by a sieve. Polyimide resin having an average particle size of 20 μm was added to the obtained powder at intervals of 0.2 wt% in the range of 0.3 to 12 wt%, and a total weight of 5 kg was added to a high-speed flow mixer (6500 RPM) having a volume of 15 l for 10 times. Mix for minutes. 15 g of the obtained powder was filled in a pellet molding die having an outer diameter of 20 mm and set in a discharge plasma sintering apparatus. The sintering conditions are a heating rate of 80 degrees / minute, a sintering temperature (holding temperature) of 270 ° C.,
Holding time 5 minutes, 10 minutes, cooling temperature 84 ° C / minute, pressure 6
50kgf / cm2, current value 1000A-1500A
And

After sintering, a columnar molded body having an outer diameter of 20 mm and a height of about 10 mm was taken out and its magnetic performance was measured. still,
For comparison, a compression-molded magnet having a polyimide resin of the same shape as a binder was prepared by hot pressing and the same measurement was performed (the polyimide resin used was a powder having an average particle size of 20 μm or less, and the addition amount was 0). The heating rate was 50 ° C./minute, the holding temperature was 270 ° C., the molding holding time was 5 minutes and 10 minutes, the cooling rate was 30 ° C./minute, and the molding pressure was 650 kgf / cm 2.

The results are shown in FIG.

From FIG. 13, the product of the present invention has a retention time of 5
The performance is saturated in minutes, but the retention time is 10 in the conventional method.
It can be seen that the product of the present invention cannot be caught up unless it is understood.
In terms of performance, it can be seen that when the holding time is 5 minutes, the product of the present invention is superior when the amount of polyimide resin added is in the range of 0.5 to 10 wt%.

Example 13 Sm and Co as raw material powders
A magnetic powder prepared by crushing an alloy containing as a main component and prepared by a casting method was used. The magnetic powder is finally crushed with a vibrating ball mill to an average particle size of about 36 μm and then sieved to 90
Those having a size of μm or more were removed. Epoxy resin powder having an average particle diameter of 20 μm was added to the obtained powder at 0.2 wt% intervals.
3 to 12 wt% is added, and the total weight of 5 kg of powder is 1 with a high-speed flow type mixer (6500 RPM) having a volume of 15 l.
Mix for 0 minutes. 15 g of the obtained powder was filled in a pellet molding die having an outer diameter of 20 mm and set in a discharge plasma sintering apparatus. The sintering conditions are a heating rate of 80 degrees / minute, a sintering temperature (holding temperature) of 230 ° C, a holding time of 3 minutes, and a cooling temperature of 84 ° C.
/ Min, pressing force 650 kgf / cm2, current value 1000
It was set to A to 1500A.

After sintering, a cylindrical molded body having an outer diameter of 20 mm and a height of about 10 mm was taken out and magnetic performance was measured. For comparison, a compression-molded magnet having an epoxy resin of the same shape as a binder was prepared and the same measurement was carried out (the epoxy resin used was a powder having an average particle size of 20 μm or less, and the addition amount was 0.
Molding pressure of 650 kgf / cm2, 3-12 wt%
After molding, the resin was baked by baking at 150 ° C. for 1 hour).

The results are shown in FIG.

It can be seen from FIG. 14 that the product of the present invention has higher performance than the conventional method, but the amount of epoxy added is 0.
The difference is clearly recognized in the range of 5 to 12 wt%.

[0066]

As described above, by using the manufacturing method according to the present invention, a uniform resin-bonded magnet with less density variation can be obtained, and molding and firing which were conventionally two steps can be performed in one step. Therefore, the time spent for manufacturing can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of a spark plasma sintering apparatus in an example of the present invention.

FIG. 2 is a density change depending on a location of a compression molding magnet using the polyamide resin according to the present invention.

FIG. 3 is a density change depending on a location of a compression molding magnet using a polyimide resin according to the present invention.

FIG. 4 is a density change depending on a place of a compression molding type magnet using an epoxy resin according to the present invention.

FIG. 5 shows the density change depending on the location of a compression molding magnet using polyethylene according to the present invention.

FIG. 6 shows the density change with time of the compression-molded magnet using the polyphenylene sulfide according to the present invention.

FIG. 7 is a density change depending on a location of a compression molding type magnet using the ABS resin according to the present invention.

FIG. 8 is a density change depending on a location of a compression molding magnet using an amino resin according to the present invention.

FIG. 9 is a density change depending on a location of a compression molding magnet using a phenol resin according to the present invention.

FIG. 10 shows the density change depending on the location of a compression molding magnet using polyethylene terephthalate according to the present invention.

FIG. 11 is a density change depending on a location of a compression molding magnet using the polycarbonate according to the present invention.

FIG. 12 is a graph showing changes in magnetic performance of a compression molding magnet using the polyamide resin according to the present invention depending on the resin amount and holding time.

FIG. 13 shows changes in magnetic performance of a compression molding magnet using a polyimide resin according to the present invention depending on the resin amount and holding time.

FIG. 14 is a graph showing changes in magnetic performance of a compression-molded magnet using an epoxy resin according to the present invention depending on the resin amount and holding time.

[Explanation of symbols]

 1 Upper electrode 2 Lower electrode 3 Upper punch 4 Lower punch 5 Type 6 Powder 7 Thermocouple 8 Power supply

Claims (15)

[Claims] 1. A method of manufacturing a resin-bonded magnet, comprising adding a thermoplastic resin or a thermosetting resin to magnetic powder and manufacturing the resin-bonded magnet by a discharge plasma sintering method. Method. 2. The method for producing a resin-bonded magnet according to claim 1, wherein the resin powder is produced by adding a polyamide resin to the magnetic powder and using a spark plasma sintering method. . 3. The method for producing a resin-bonded magnet according to claim 1, wherein the resin powder is produced by adding a polyimide resin to the magnetic powder and using a discharge plasma sintering method. . 4. The method for producing a resin-bonded magnet according to claim 1, wherein an epoxy resin is added to the magnetic powder and the resin-bonded magnet is produced by a spark plasma sintering method. . 5. The method for producing a resin-bonded magnet according to claim 1, wherein polyethylene is added to the magnetic powder and the resin-bonded magnet is produced by a discharge plasma sintering method. 6. The method for producing a resin-bonded magnet according to claim 1, wherein polyphenylene sulfide is added to the magnetic powder and the magnet is produced by a spark plasma sintering method.
A method for producing the resin-bonded magnet described. 7. The method for producing a resin-bonded magnet according to claim 1, wherein ABS resin is added to the magnetic powder and the resin-bonded magnet is produced by a spark plasma sintering method. . 8. The method for producing a resin-bonded magnet according to claim 1, wherein the resin powder is produced by adding an amino resin to the magnetic powder and using a discharge plasma sintering method. . 9. The method for producing a resin-bonded magnet according to claim 1, wherein phenol resin is added to the magnetic powder and the resin-bonded magnet is produced by a discharge plasma sintering method. . 10. A method of manufacturing a resin-bonded magnet, comprising:
The method for producing a resin-bonded magnet according to claim 1, wherein polyethylene terephthalate is added to the magnetic powder and the magnetic powder is produced by a discharge plasma sintering method. 11. A method of manufacturing a resin-bonded magnet, comprising:
2. The method for producing a resin-bonded magnet according to claim 1, wherein polycarbonate is added to the magnetic powder and the magnetic powder is produced by a discharge plasma sintering method. 12. A method for manufacturing a resin-bonded magnet, comprising:
The method for producing a resin-bonded magnet according to claim 2, wherein 0.5 to 10 wt% of polyamide resin is added to the magnetic powder and the magnetic powder is produced by a discharge plasma sintering method. 13. A method of manufacturing a resin-bonded magnet, comprising:
The method for producing a resin-bonded magnet according to claim 3, wherein 0.5 to 10 wt% of a polyimide resin is added to the magnetic powder and the magnetic powder is produced by a discharge plasma sintering method. 14. A method of manufacturing a resin-bonded magnet, comprising:
Add 0.5 to 10 wt% of epoxy resin to magnetic powder,
The method of manufacturing a resin-bonded magnet according to claim 4, wherein the resin-bonded magnet is manufactured by using a discharge plasma sintering method. 15. A resin-bonded magnet manufactured by using the spark plasma sintering method according to claim 1 in a resin-bonded magnet.