JPS6318602A - Manufacture of permanent magnet of rare earth-iron system - Google Patents

Abstract

PURPOSE:To obtain a high-performance permanent magnet by producing crystalline thin bands of a permanent magnet alloy of the rare earth-iron system, and then stacking, heating and integrating them, or grinding them and kneading them in a binder for molding. CONSTITUTION:An alloy represented by the formula I is used (where R is Y and at least one of the rare earth elements; M is one or more combination containing Ga of Ga, A, Ti; and B, Fe, Co are contained with the atomic ratios alpha-delta of equation II). If Nd and Pr are contained in R to 70% or more and a part of B is substituted by C, N or the like to about 80%, high BHmax is obtained. This molten alloy is jetted onto a cooling body rotating at a predetermined speed. The obtained crystalline thin bands are stacked and integrated at 600-1100 deg.C, 0.1-2 tons/cm<2>. Alternately, the alloy ingot is made into powder of 5-30mum (0<beta<=0.95). After receiving surface treatment for anti-oxidizing and improvement of bond properties with resin, it is kneaded with 10wt.% thermoelastic resin 6 and injection molded. With this arrangement, a permanent magnet of high magnetic flux density, coercive force and Curie point and large energy product is obtained.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a method for manufacturing a rare earth iron permanent magnet.

(Conventional technology) Rare earth Co-based permanent magnets have been known for a long time.

This permanent magnet has a high energy product and is therefore used in a wide range of fields. Recently, rare earth iron-based permanent magnets having even higher energy products (for example, 308 GOe) have been studied. This rare earth iron-based permanent magnet is a promising material because it has a high energy product and also has the advantage of being inexpensive compared to Co-based magnets because it is mainly composed of Fe.

This rare earth iron-based permanent magnet is manufactured using the 5 normal method, that is, grinding and sintering after alloy formation, but it requires steps such as pressing in a magnetic field after grinding, and has the disadvantage that the process is complicated. In addition, there is a risk of contamination with impurities during the manufacturing process, particularly during the pulverization process, and there is a drawback that stable magnetic properties are difficult to obtain.

On the other hand, in recent years, instead of the sintering method that has been the mainstream method for manufacturing ferrite and rare earth cobalt magnets, a manufacturing method using an injection molding method using a thermoplastic resin as a binder has been developed. This is because even thin-walled magnets or magnets with radial anisotropy, which are difficult to manufacture using the sintering method, can be manufactured relatively easily using the injection molding method. For these reasons,
Regarding ferrite or rare earth cobalt magnets, production of injection molded magnets began several years ago, and has now developed to the point where it has formed a large market for centering magnets for cathode ray tubes, motors, etc.

However, the ultra-high performance (!1lIILa
Although injection molded magnets with higher performance are expected for rare earth iron-based magnets (35MGOe),
The injection molding method has not yet been abandoned at the industrial level, and the main reason for this is that, at present, magnetic alloy powder with good magnetic properties (especially coercive force properties) is produced only after pulverizing the quenched ribbon. On the other hand, the present invention was made in consideration of the above points.

An object of the present invention is to provide a method for producing a rare earth/iron permanent magnet that can easily obtain a rare earth/iron permanent magnet having a high magnetic flux density, high coercive force, high cue, and a large energy product.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides that when a rare earth/iron permanent magnet alloy is produced by a molten metal quenching method, the C-axis of the ribbon is oriented perpendicularly to the G-band surface. It is based on what we have discovered.

That is, the present invention involves a first step of obtaining a crystalline ribbon made of a rare earth/iron permanent magnet alloy by a molten metal quenching method, and a method of integrating the oriented crystalline ribbons obtained in the first step by heating after laminating them. or the oriented crystalline ribbon obtained in the first step is crushed to about 10 to 100 tones, kneaded in a binder such as resin, and then molded and solidified in a magnetic field or in the absence of a magnetic field to be integrated. A method for manufacturing a rare earth iron permanent magnet, comprising the steps of:

Rare earth/iron permanent magnet alloys include yttrium and C8,
Pr, Nd, SI! The main components are at least one selected from the 1st class rare earth gold M (or metals containing multiple rare earth elements (M, M)) and iron, and further contain non-metals such as B and C for stabilization. It is something that For example, taking B as an example, R1-a-p-'i-5''aFepCoyM6R:Y,
Rare earth M: A combination of one or more of Ga, Al, and Ti, including Ga.

0.001≦α≦0.5 0.5≦β≦0.95 0<γ≦0.3 0 δ≦0.1 α+β+γ+δ<1.0 Here α(0,001, β>0.95 If γ>0.3, the coercive force will not improve and it will be unsuitable as a permanent magnet alloy.
α>0.5. When β<0.5, the magnetic flux density decreases, making it unsuitable as a permanent magnet.

Among rare earth elements, Nd and Pr are particularly high (BH)
, a, and preferably contains at least one of these two elements as R.The proportion of Nd and Pr in the R amount is 70% or more (the R amount may be the entire amount) ) is desirable.

Examples of materials equivalent to B include C, N, Si, P, Ga, and the like. A part of B may be replaced with these elements, thereby improving sinterability and thus Br.

(Bo) may be increased. In this case, it is desirable that the amount of substitution is up to about 80% of B.

Co is an element that is effective in increasing the cutting temperature and, in turn, improving the temperature characteristics or corrosion resistance of the magnet.

Among Ga, Al, and Ti, elements consisting of a combination of one or more types including Ga are effective elements for improving coercive force and improving corrosion resistance, but when the atomic ratio exceeds 0.1, a decrease in Br is noticeable. Become.

When such a rare earth/iron permanent magnet alloy is formed into a thin ribbon by a molten metal quenching method, the C-axis is oriented perpendicularly to the surface of the ribbon under certain cooling conditions. This is a phenomenon not seen in Sm-Co systems. The manufacturing process is similar to that used for amorphous alloys. That is, the molten alloy is ejected onto the cooling rotary cooling body to form a thin ribbon.

At this time, if the rotational speed of the rotary cooling body is too high, the ribbon becomes amorphous and is not oriented and does not function as a permanent magnet. On the other hand, if the rotation speed is slow, although the material becomes crystalline, the crystal grains become columnar and the orientation deteriorates, resulting in poor magnetic properties. Considering this, it is preferable that the surface speed of the rotary cooling body is in the range of 3 to 20 m/sec.

The crystalline ribbon thus obtained is integrated and magnetized by the following method. The first method is to stack crystalline ribbons in a desired shape and integrate them by heating. The heating temperature varies depending on the composition, but it is required to be at least 600°C for integration, and preferably below β00°C to prevent liquid phase crystallization. The processing time is 0.1
About H to 5H is sufficient.

In addition, in order to obtain a larger energy product, it is preferable to apply a pressure of about 0.1 to 2 ton/ad during heating and integration.

The second method is to coarsely crush the above alloy ingot using a show crusher V, and then use a jet mill or the like to reduce the average particle size to 5 to 30. magnetic powder. This magnet powder is surface treated with a silane coupling agent, etc. to prevent oxidation of the magnet powder.

Improves bondability with thermoplastic resin.

Next, the magnet powder after the first surface treatment and the thermoplastic resin are mixed and mixed well using a pestle or an agitating mixer. At this time, the ratio of resin to magnet powder is 3 to 1 by weight.
0%, preferably 6-10%. This is because if it is less than 3%, the mechanical properties of the magnet powder will deteriorate significantly, while if it exceeds 10%, the magnetic properties will deteriorate. As the thermoplastic resin, various resins such as polyamides such as nylon 6 and nylon 66, polyolefins such as ethylene and polypropylene, vinyl chloride, and polyester can be used.

Next, the mixed powder is molded by injection molding in a warm magnetic field to produce a permanent magnet. The heating temperature at this time is 23
0~300℃, pressurizing force 0.3~2 ton/QJ,
The applied magnetic field is 15 kOa or more. Heating temperature is 230℃
If it is less than this, the fluidity of the mixed powder will be poor, the mixing of the magnet powder and the resin will be insufficient, the non-uniformity of the compact will increase, and the magnetic properties will deteriorate. On the other hand, if the temperature exceeds 300° C., the resin will decompose and gas will be generated, making it impossible to obtain good magnetic properties due to the presence of pores and the like.

(Example) Examples of the present invention will be described below.

Example 1 Nd0.17 Bo, 06 Fe0.59 Co0.1
An alloy having a composition of 6 Ga0.02 was formed into a thin ribbon using a molten metal quenching method.

That is, a molten alloy was injected and cooled by argon gas pressure through a quartz nozzle onto the surface of a roll rotating at about 10 m/sec to obtain a crystalline ribbon with a width of 10 nm and a thickness of 100 μs. The results of measuring the obtained 'f4 band using an X-ray diffraction apparatus are shown in FIG. 1, and for comparison, the results of X-ray diffraction of the alloy powder material are shown in FIG.

It can be seen that, compared to the alloy powder material, in the case of the molten metal quenched 'gt zone, the C axis is oriented in the direction perpendicular to the ribbon surface.

The thin strip obtained by the molten metal quenching method was cut into strips with a length of Low, and 100 strips were laminated to produce a 2 ton/a+? Heat treatment at 700° C. x 10 ml was performed while pressure molding was carried out at a pressure of 10 ml. The obtained magnetic properties are shown in Table 1.

Example 2 Nd0.10 Pr0.08 Bo, 10 Fe0.5
6 Goo, 14 Ga0.0IAI20.01 thin strips of magnetic alloy were created and laminated in flake form, then 2to
680℃ x 10m1 while pressure molding with n/cJ pressure
A heat treatment of n was performed. The obtained magnetic properties are shown in Table 1.

Example 3 Nd0.15 Bo,06 Fe0.61 CoO,1
Thin strips of magnetic alloy 6GaO,02 were prepared and laminated in the same manner as in Example 1, and heat treated at 710° C. x 20+*in while being press-formed at a pressure of 2 tons/ffl. The results obtained are shown in Table 1.

Example 4 Nd0.15 Bo, 08 FeO, 59 GoO, 16
Thin strips of magnetic alloy Ga0.01 TlO,01 were prepared, laminated in the same manner as in Example 1, and heat-treated at 700° C. The results obtained are shown in Table 1.

For comparison, the characteristics of a permanent magnet having the same composition as Examples 1 to 4 and made by the powder sintering method are also shown. , by using the method of the present invention, the coercive force (i) Ic) and energy f! can be reduced compared to the conventional method. It can be seen that ((BH)wax) is improved.

This means that there is no crushing process, so there is no risk of contamination with impurities.
Also, this seems to be an effect of the lamination heat treatment.

In addition, the conventional powder sintering process of crushing, pressing in a magnetic field, and other steps can be omitted, making manufacturing easy.

Example 5 The melt quenched ribbons obtained in Examples 1 to 4 were milled in a ball mill to reduce the average particle size to 30. crushed to.

After applying a silane coupling agent to each magnet powder, 6% by weight of nylon is added and mixed, and the heating temperature is 280.
C, a molding pressure of 2 ton/a#, and an applied magnetic field of 15 koe were injection molded to produce a permanent magnet.

Table 2 shows the results of investigating the magnetic properties of these permanent magnets.

As is clear from Table 2, by using the method of the present invention, injection molded magnets having characteristics exceeding 10 MGOe can be easily produced.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to omit processes such as crushing and pressing in a magnetic field in the conventional method, and to achieve a significant simplification of the process, as well as to achieve injection molding, which was previously impossible. permanent magnets can also be produced, and the magnetic properties of the obtained permanent magnets are also improved.

[Brief explanation of the drawings] Figure 1 shows NdO, 17Bo, 06 Fe0 according to the present invention.
．． xlIi1 diffraction diagram of 59CoO,16Ga0.02 ribbon. Figure 2 shows Nd0.17 Bo, 06 Fe0.59 C
X-ray diffraction diagram of oO,16Ga0.02 powder. Agent Patent attorney Yudo Noriyuki Chika Kikuo Takehana 2 (9 (deg) 2e (deg) Figure 2

Claims (1)

[Claims] (1) R_1_-_α_-_β_-_γ_-_δB_αFe_ created by molten metal quenching method
βCo_γM_δ (α, β, γ, δ are atomic ratios) where R
: Y and at least one rare earth element M: Ga, Al,
A combination of one or more Ti and Ga, 0.001≦α≦0.5 0.5≦β≦0.95 0<γ≦0.3 0<δ≦0.1 α+β+γ+δ<1 A method for manufacturing a rare earth iron permanent magnet, characterized by using a rare earth iron permanent magnet alloy ribbon having the following properties. (2) R_1_-_a_-_β_-_γ_-_δB_αFe_ created by molten metal quenching method
βCo_γM_δ (α, β, γ, δ are atomic ratios) where R
: Y and at least one rare earth element M: Ga, Al
, Ti, a combination of one or more types including Ga, 0.001≦α≦0.5 0.5≦β≦0.95 0<γ≦0.3 0<δ≦0.1 α+β+γ+δ<1 A method for producing a rare earth iron permanent magnet according to claim 1, characterized in that crystalline ribbons made of a rare earth iron permanent magnet alloy having the following composition are heated and integrated. (3) R_1_-_a_-_β_-_γ_-_δB_αFe_ created by molten metal quenching method
βCo_γM_δ (α, β, γ, δ are atomic ratios) where R
: Y and at least one rare earth element M: Ga, Al
, Ti, a combination of one or more types including Ga, 0.001≦α≦0.5 0<β≦0.95 0<γ≦0.3 0<δ≦0.1 α+β+γ+δ<1 2. A method for producing a rare earth iron permanent magnet according to claim 1, wherein the crystalline ribbon made of a rare earth iron permanent magnet alloy is mixed with a binder and integrated.