JPH01290205A - Manufacture of high-polymer composite type rare-earth magnet - Google Patents

Abstract

PURPOSE:To obtain a polymer composite type rare-earth magnet having anisotropy whose magnet characteristic is excellent by a method wherein a heat-treated molded substance is impregnated with a high-polymer resin and composite-molded. CONSTITUTION:An R2T14B-based (where R represents Y and at least one kind of rare-earth elements and T represents a transition element) ingot containing Nd, Fe and B as main components is crushed finely; after that, a powder molded substance which has been obtained by a molding operation in a magnetic field is sintered to form a sintered substance whose crystal orientation degree is high. Then, this sintered substance is crushed; after that, a powder, for molding use, is adjusted so as not to contain a powder whose particle diameter is less than 10mum; the powder is molded in the magnetic field and heat-treated; after that, this heat-treated molded substance is impregnated with a polymer resin. It is desirable that a heat-treatment temperature for a heat-treatment process is within a range of 480-1120 deg.C. By this setup, it is possible to obtain an R-T-B- based polymer composite type magnet having a high magnetic characteristic.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method of manufacturing a polymer composite magnet, typically a so-called rubber magnet or a plastic magnet.
R2 whose main components are rare earth metals (R), transition metals (T), and boron (B), typified by Fe-B permanent magnets.
This invention relates to improving the magnetic properties of a polymer composite rare earth magnet using T 14 B-based rare earth magnet powder.

[Prior Art] A polymer composite magnet is one in which magnet powder is dispersed in a polymer resin, or one in which magnet powder is bound with a polymer resin. This magnet has various advantages not found in cast magnets, sintered magnets, etc., such as elasticity and ease of processing, and is used in various fields. However, this polymer composite magnet consists of magnetic powder and non-magnetic v! Since it is made of J#, it has the disadvantage of having lower magnetic properties than sintered magnets and the like. Therefore, attempts are being made to achieve high magnetic properties by making the powder anisotropic, such as by orienting the powder in a magnetic field.

Various types of magnet powder have been used to disperse and bind, but a representative example is Nd-Fe/B sintered magnet powder, which currently exhibits high magnetic properties. .

[Problems to be solved by the invention] Conventional polymer composite magnets using rare earth magnet powder are made by heat-treating an alloy ingot obtained by melting raw materials, pulverizing it, mixing the powder with polymer resin, It was manufactured by molding in a magnetic field. The magnet alloy powder used here was desirably composed of fine single crystal grains in order to improve crystal grain orientation in a magnetic field. However, Nd
-In R2T I4B alloys represented by Fe/B magnets, mechanical stress during crushing causes a decrease in coercive force (IHc), and in fine regions where the powder is composed of single crystal grains, IHc was decreasing. Therefore, in a manufacturing method using a molten ingot as a starting material, even if a sintered magnet having a high IHc is crushed and used as magnet powder, the result is a polymer composite magnet that exhibits extremely poor magnetic properties.

On the other hand, R-
A liquid quenching method is known as a method for producing a T-B magnet alloy. However, the powder obtained by this manufacturing method could not achieve anisotropy. Subsequently, it was discovered that by hot working this liquid quenched alloy, it was possible to obtain magnet powder that could be made anisotropic.
Since it requires high temperature and high pressure, the equipment is expensive and large-scale, and there are concerns about stabilizing the characteristics in the manufacturing state, so although it may not be useful from an industrial perspective. sea bream.

Therefore, the technical problem of the present invention is to provide a method for manufacturing a high-performance anisotropic polymer composite rare earth magnet by utilizing the normally practiced manufacturing process of R-T-B sintered magnets. It is something to do.

[Means for Solving the Invention] According to the present invention, an R2T14B (R represents at least one of Y and a rare earth element, T represents a transition element) ingo.y containing Nd, Fe, and B as main components. A first magnetic field compaction step of pulverizing the powder to produce an initial powder, and then compacting the initial powder in a first magnetic field to produce a first magnetic powder compact, and this first magnetic powder compaction. A sintering process in which the body is sintered to produce a sintered body, a sintered body crushing process in which this sintered body is crushed to generate a sintered body crushed powder, and this sintered body crushed powder is processed into a second process. A second magnetic field forming step of forming in a magnetic field to produce a second magnetic powder compact; a heat treatment step of heat treating the second magnetic powder compact to produce a heat-treated compact; and a heat-treated compact. In the method for manufacturing a polymer composite rare earth magnet, the resin composite molding step includes composite molding by impregnating the heat-treated molded body with a polymer resin. A method for manufacturing a polymer composite rare earth magnet is obtained. Here, it is desirable to include a quenching step of quenching the heat-treated molded article after the heat treatment temperature is maintained.

Further, according to the present invention, after pulverizing an R2T14B ingot containing Nd, Fe, and B as main components (R represents at least one of Y and a rare earth element, and T represents a transition element) to generate an initial powder. , a first magnetic field compacting step in which this initial powder is compacted in a first magnetic field to produce a first magnetic powder compact, and this first magnetic powder compact is sintered to produce a sintered compact. a sintering process of pulverizing the sintered body to produce a sintered body pulverized powder; a heat treatment process of heat-treating the sintered body pulverized powder to produce a heat-treated molded body; The heat-treated molded product is pulverized to produce a heat-treated molded product powder, and the heat-treated molded product powder is mixed with a polymeric IfA resin and then compression molded or injection molded in a secondary magnetic field. A method for manufacturing a molecular composite rare earth magnet is obtained.

In the above-described two methods of manufacturing a polymer composite rare earth magnet of the present invention, the heat treatment temperature in the heat treatment step is 4.
The temperature is preferably within the range of 80 to 1120°C.

Furthermore, in the above-described two methods of manufacturing a polymer composite rare earth magnet of the present invention, the sintered body pulverizing step is performed so that the particle size of the sintered body pulverized powder is substantially within the range of 10 μm to 1 μm. It is desirable to crush the sintered body so that

That is, the present invention involves pulverizing an alloy ingot obtained by melting, sintering the obtained powder compact by compacting it in a magnetic field to form a sintered compact with a high degree of crystal orientation, and then After pulverizing the sintered body, a molding powder adjusted so as not to contain powder with a particle size of less than 10 μm is (1) molded in a magnetic field and heat-treated, and then the heat-treated molded body is impregnated with a polymer resin.

■ After heat treatment, it is mixed with polymer resin and molded in a magnetic field.

As a result, an RTB-based polymer composite magnet having high magnetic properties is realized.

The improvement in magnetic properties of the present invention is related to the improvement in IHc and Br due to heat treatment, and this effect is deeply attributable to the fact that the molding powder is composed of a plurality of oriented crystal grains. The present inventors discovered this as a result of various experiments.

The present invention produces R2T14B by crushing R2T14B sintered bodies.
In the method for manufacturing a B-based polymer composite magnet, the particle size of the molding powder prepared by crushing the sintered body is in the range of 10 μm to 1 fl, and the magnet manufacturing process includes magnetic field molding and heat treatment of the magnet powder. It is possible to achieve high magnetic properties, which is very useful industrially.

The reason why the particle size of the sintered compact powder was set to be 10 μm or more is because if the particle size is larger than this, the improvement in IHC due to heat treatment becomes significant, and at the same time, the improvement in B r, (BH), , x becomes significant. It is. For powders with a diameter of 10 μm or less, it is difficult for the magnetic alloy to significantly recover from damage caused by crushing even if heat treatment is performed. On the other hand, the reason why the upper limit of the average pulverized particle size was set as III is that if the particle size is larger than this, the homogeneity of the polymer composite magnet will decrease, and at the same time, it may cause mold breakage during powder compaction or the fluidity may deteriorate. This is because inconveniences such as non-uniformity occur.

Furthermore, even if the minimum particle size of the powder is set to 10 μm or more, the magnetic properties will be improved due to the contribution of the IHc improvement in the present invention, but depending on the particle size distribution state of the powder, the space factor of the magnetic powder will decrease. , Br decreases, (BH)
laX may also decrease.

However, this phenomenon can be easily improved by changing the particle size distribution of the powder, and is not a negative effect of the present invention.Examples will be described below with reference to the drawings.

[Example] Example 1 Nd with a purity of 97 wt% (the remainder is other rare earth elements mainly consisting of Ce and Pr), ferroboron (B purity about 20 wt%)
) and electrolytic iron, the rare earth element (R) is 34.0w
t%, B is 1. The alloy was melted by high-frequency heating in an argon atmosphere to obtain an alloy ingot such that the remaining content was Fe.

Next, this alloy ingot was coarsely ground, and then finely ground to an average particle size of 2 μm using a ball mill. This alloy powder was molded into a rectangular parallelepiped shape under a pressure of 1 ton/aa in a magnetic field of 20 KOe.
After holding at 0°C for 1 hour, it was held in Ar for 3 hours to obtain a sintered body. This sintered body has a density of 7.55 gr/am3 and an average grain size of about 8 μm. Part of this 6
When the magnetic properties were measured after aging at 00°C for 2 hours, B
G at r 13.7, Oe at IHc12.5, (
BH) Ilax44. It was about ON, G, Oe.

On the other hand, for the sintered body that is not subjected to aging treatment, 500 μm
After coarsely pulverizing to the following particle size, each
m or less, 40 μm or less, 60 μm or less, 80 μm or less,
Powder particles of 100 μm or less were removed, and the product was molded into a disk shape under a molding pressure of 2 john/cIi in a magnetic field of about 20 Oe.

Next, these molded bodies were held in vacuum at 1000° C. for 1 hour, and then held in Ar for 1 hour to be rapidly cooled.

The density (G, D,) of these molded bodies is 5.8 to 6.4 gr
/am3.

Next, these molded bodies were evacuated, impregnated with epoxy resin, and then held at 80° C. for 5 hours to be cured to obtain a polymer composite magnet. Figure 1 shows the measurement results of its magnetic properties.

Further, for comparison, the above-mentioned aged sintered body was similarly subjected to coarse pulverization, molding in a magnetic field, and polymer composite formation by impregnation with epoxy resin, and its magnetic properties were measured. The result is G, D, 5.4 (lr/am3°Br5.1)
, IHc 2.5 to Oe, (BH),, x3.
They were OH, G, and Oe.

As shown in the first diagram, by removing powder having a particle size of 10 μm or less, the magnetic properties are significantly improved.

Example 2 Cerium dididium, dysprosium, ferroboron, electrolytic iron, consisting of 5 wt% Ce, 15 wt% Pr, and the balance Nd (however, other rare earth elements were included as Nd).
Using electrolytic cobalt, (Ce
-Pr-Nd) is 31.0wt%Dy is 2.5wt%
An R-T-B ingot containing 7 wt% of Co and the balance of Fe was obtained.

Next, in the same manner as in Example 1, the powder was pulverized to an average particle diameter of 2 μm, followed by compacting in a magnetic field and sintering at 1050°C. The density of this sintered body is 7.55or/aI13,
The average crystal grain size was approximately 6 μm. The magnetic properties of some of these aged at 600°C for 2 hours are B r 12.
3KG, IHc14.5 to Oe, (BH) lax
It was 34.5H, G, Oe.

On the other hand, a sintered body that was not subjected to aging treatment was coarsely pulverized in the same manner as in Example 1, and after removing powder of 20 μm or less, 40 μm or less, 60 μm or less, 80 μm or less, and 100 μm or less, it was heat treated at 600° C.

Next, after crushing this heat-treated powder, 40 VO 1% polyethylene was mixed, and 20 KO
A polymer composite magnet was obtained by injection molding into a mold while applying a magnetic field of e. Figure 2 shows the measurement results of the magnetic properties.

For comparison, the above-mentioned aged sintered body was similarly coarsely pulverized, mixed with polyethylene, and then made into a polymer composite magnet by injection molding.The characteristic values were Br4.6, G,
I) Ic3.5KOe, (BH)
1. x 3.5H, G, Oe.

As shown in the second diagram, by removing powder having a particle size of 10 μm or less, the magnetic properties tend to be significantly improved.

As shown in the above examples, R 2 having anisotropy
By not containing powder particles of 10 μm or less in the molding powder produced by pulverizing the T 1t, B-based sintered alloy, a significant improvement in magnetic properties is achieved.

The above embodiments are based on Nd-Fe-B.

Although only the Ce-Pr-Nd-Fe-Co-B system has been described, a part of Nd may be replaced with Y and other rare earth elements such as Gd,
Tb, Ho, etc. may be substituted, a portion of Fe may be substituted with other transition metals such as Mn, Cr, Ni, etc., and a portion of B may be substituted with other semimetals such as Si.

Even if it is replaced with C etc., the composition of the magnet alloy remains Nd-Fe・B.
is part of the main component, and Nd is also included in the compound system of the magnet.
It can be easily inferred that the effects of the present invention can be fully expected as long as R2T14B, such as the 2Fe14B system, contributes to magnetism.

In addition, in this example, only epoxy resin and polyethylene were described as polymer resins, but any material (for example, other polymer Even if it is not only resin, rubber, etc., but also metal), it is within the scope of the present invention.
Those skilled in the art can easily understand this.

In addition, regarding the manufacturing method of polymer composite magnetization shown in this example, only the impregnation type in which the molded body is impregnated with resin and the injection molding type in which the powder and resin are kneaded and then injection molded are described. For example, those skilled in the art can easily guess that it can be applied to a compression molding mold in which powder and vA fat are mixed and then compression molded, extrusion molding, roll molding, etc.

[Effects of the Invention] According to the present invention, a polymer composite rare earth magnet having excellent anisotropy in magnetic properties can be produced by utilizing the commonly practiced manufacturing process of RT-B sintered magnets. A manufacturing method can be provided.

Further, according to the present invention, an impregnated type, using sintered body powder as a raw material,
Since it is possible to provide a wide range of manufacturing methods for polymer composite rare earth magnets, such as compression molding molds and injection molding molds, it is very useful industrially.

[Brief explanation of the drawing]

Figure 1 shows the removed maximum particle diameter of the molding powder prepared by removing a part of the powder obtained by coarsely pulverizing the sintered body in Example 1 of the present invention, and the polymer composite mold using this molded body powder. Figure 2 shows the relationship between the characteristics of rare earth magnets and the maximum particle size of the molding powder produced by removing a part of the powder obtained by coarsely pulverizing the sintered body in Example 2 of the present invention. FIG. 3 is a diagram showing the relationship with the characteristics of a polymer composite rare earth magnet using molded body powder. Figure 1 Diameter of crushed powder grains (μm)

Claims (3)

[Claims] 1. R_2T_ containing Nd, Fe, and B as main components
1_4B system (R is at least one of Y and a rare earth element,
T represents a transition element. ) A first magnetic field compaction step of pulverizing the ingot to produce an initial powder, and then compacting the initial powder in a first magnetic field to produce a first magnetic powder compact; and the first magnetic field powder compaction. a sintering process of sintering the sintered body to produce a sintered body; a sintered body crushing process of crushing the sintered body to generate a sintered body crushed powder; and a second process of the sintered body crushed powder. a second magnetic field compacting step of forming in a magnetic field to produce a second magnetic powder compact; a heat treatment step of heat-treating the second magnetic powder compact to produce a heat-treated compact; and the heat-treated compact. In the method for manufacturing a polymer composite rare earth magnet, the method includes a resin composite molding step of compositely molding a magnet with a polymer resin, wherein the resin composite molding treatment step performs composite molding by impregnating the heat-treated molded body with a polymer resin. A method for manufacturing a polymer composite rare earth magnet, characterized by the following. 2. R_2T_ containing Nd, Fe, and B as main components
1_4B system (R is at least one of Y and a rare earth element,
T represents a transition element. ) A first magnetic field compaction step of pulverizing the ingot to produce an initial powder, and then compacting the initial powder in a first magnetic field to produce a first magnetic powder compact; and the first magnetic field powder compaction. a sintering process of sintering the body to produce a sintered body; a sintered body crushing process of crushing the sintered body to generate a sintered body crushed powder; heat-treating the sintered body crushed powder; A heat treatment step for producing a heat-treated compact; pulverizing the heat-treated compact to produce heat-treated compact powder; mixing the heat-treated compact powder with a polymer resin; and then compressing the heat-treated compact in a secondary magnetic field. A method for producing a polymer composite rare earth magnet, which comprises molding or injection molding. 3. In the method for manufacturing a polymer composite rare earth magnet according to claim 1 or 2, the sintered body pulverizing step is performed so that the sintered body pulverized powder has a particle size substantially within the range of 10 μm to 1 mm. A method for manufacturing a polymer composite rare earth magnet, which comprises pulverizing the sintered body so that the sintered body is crushed.