JPH1041114A - Manufacture of powder for high molecular composite type rare earth magnet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide manufacture of anisotropic powder for high molecular composite type rare earth magnet which has large residual magnetic flux density (Br) and maximum energy product ((BH)max ) and superior magnet characteristics. SOLUTION: When powder for high molecular composite type rare earth magnetic of R-T-B based (R is a rare earth element, with Nd as a main component, containing Y, 2.0<R<13.5at.%, and T is a transition metal with Fe and Co as main components, 70.0<T<89.0at%, and 4.0<B<20.0at% for B) is manufactured, R-T-B based alloy is rapidly quenched to obtain amorphous powder, and then the powder is heat-treated at 650-1000 deg.C in hydrogen, and further, dehydrogenated at 650-1000 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a powder for a polymer composite type rare earth magnet, and more particularly to a method for producing N for a bonded magnet.
The present invention relates to a method for producing a d-Fe-B-based alloy powder.

[0002]

2. Description of the Related Art In recent years, the development of bond magnets (compression molding dies, injection molding dies) using an RTB-based alloy powder has been advanced and used by various users. As a method for producing such an Nd—Fe—B alloy powder for bonded magnets, there is a method for producing an alloy ingot by a liquid quenching method. As a result, the obtained powder is an isotropic powder having Nd ₂ Fe ₁₄ B as a main phase.

[0003] In recent years, attention has been focused on reducing the composition value of R to obtain an R-T-B-based alloy ingot with a low R as a main phase containing Fe ₃ B and α-Fe produced by a liquid quenching method. Isotropic powder. This powder is used for a spring magnet. The RTB-based spring magnet is a nanocomposite isotropic hard magnetic material in which Fe ₃ B and α-Fe having soft magnetism and Nd ₂ Fe ₁₄ B having hard magnetism coexist in the same tissue. is there. The metal structure is composed of fine crystal aggregates having an average crystal grain size of about 20 nm, and each particle is coupled by strong interparticle interaction, has a high residual magnetic flux density (Br), and has a magnetization in a demagnetizing field. It shows a unique recoil behavior of reversible springback.

However, the powder obtained by the above manufacturing method is isotropic and has a low Br because amorphous and fine crystal grains are magnetically randomly arranged. For this reason, the maximum energy product [(BH) _max ] is low, and industrially useful magnet properties are not obtained with a bonded magnet obtained using this.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention solves the above-mentioned problems and provides an anisotropic polymer composite type rare earth magnet powder having a large Br and (BH) _max and excellent magnet properties. It is to provide a manufacturing method.

[0006]

Means for Solving the Problems The present inventors have conducted various studies on the above-mentioned problems, and as a result, have found that a powder produced by a liquid quenching method using an RTB-based alloy ingot is used.
It has been found that anisotropic powder can be obtained by performing forced dehydrogenation after heat treatment in hydrogen to occlude hydrogen.

That is, when a Nd-Fe-B alloy ingot is heat-treated in hydrogen, Nd ₂ Fe ₁₄ B is decomposed into NdH ₂ , α-Fe, Fe ₂ B and Fe ₃ B at around 650 ° C. Nd ₂ Fe ₁₄ B is recrystallized in the subsequent dehydrogenation process. By grinding this, an anisotropic powder is obtained.

That is, the present invention relates to an RTB-based polymer composite type rare earth magnet powder (R is a rare earth element containing Nd as a main component and containing Y, 2.0 <R <13.5 at%). , T is F
e, a transition metal containing Co as a main component, and 70.0 <T <8
9.0 at%, B is 4.0 <B <20.0 at%). In the manufacturing method, the RTB-based alloy is rapidly quenched by liquid to obtain an amorphous powder, and the powder is hydrogenated at 650 to 1000 ° C. This is a method for producing a polymer composite type rare earth magnet powder, which is subjected to a medium heat treatment and further to a dehydrogenation treatment at 650 ° C. to 1000 ° C.

Further, the present invention relates to an RTB-M-based polymer composite type rare earth magnet powder (R is a rare earth element containing Nd as a main component and containing Y, and 2.0 <R <13. 5at%, T
Is a transition metal mainly composed of Fe and Co, and is 70.0 <T
<89.0 at%, B is 4.0 <B <20.0 at%, M
Is at least one of Ga, Zr, Si, Cr, Ti, V, and Al).
Liquid quenching of the base alloy to obtain an amorphous powder, and heat treating the powder in hydrogen at 650 ° C. to 1000 ° C .;
This is a method for producing a polymer composite type rare earth magnet powder, which is subjected to a dehydrogenation treatment at a temperature of from 1000C to 1000C.

Further, the present invention provides the above method for producing a powder for a polymer composite type rare earth magnet, wherein the heat treatment in hydrogen and the dehydrogenation are performed in a unidirectional magnetic field of 100 Oe or more. This is a method for producing a molecular composite rare earth magnet powder.

In the present invention, the composition of R is from 2.0 to 13.
The reason for setting it to 5 at% is that if it is less than 2.0 at%, there is almost no coercive force, and if it exceeds 13.5 at%,
This is because Br decreases and (BH) _max decreases. Also, 70.0 <T <89.0 at%, 4.0 <B <20.0
The reason for setting at% is that if the ratio exceeds this range, the magnetic properties deteriorate.

Further, the temperature for performing the heat treatment in hydrogen is 650 ° C.
The reason why the temperature is set to 1000 ° C. is that Nd ₂ F
e ₁₄ B is not decomposed into NdH ₂ , α-Fe, Fe ₂ B,
It is to remain as d ₂ Fe ₁₄ BH _x. Conversely, 1000
C., the Nd ₂ Fe ₁₄ B becomes NdH ₂ , α-Fe, F
This is because Nd ₂ Fe ₁₄ B + H ₂ず is obtained without being decomposed into e ₂ B.

Further, the temperature for performing the dehydrogenation treatment is 650 ° C.
The reason why the temperature is set to 1000 ° C. is that if the temperature is outside this range, the effect of the dehydrogenation treatment cannot be obtained.

Further, in the present invention, since the Curie temperature of Fe and Fe—Co generated by the occlusion of hydrogen is 770 ° C. or higher, the magnetic field is applied by applying a magnetic field when performing the heat treatment in hydrogen and the dehydrogenation treatment. The crystal orientation can be uniformly aligned.

The reason why the applied magnetic field during the heat treatment and the dehydrogenation treatment in hydrogen is set to 100 Oe or more is that when the applied magnetic field is less than 100 Oe, there is no remarkable difference in the magnetic properties of the powder from the powder treated without applying the magnetic field. This is because there is no effect of applying a magnetic field.

[0016]

Embodiments of the present invention will be described below.

(Example 1) Nd having a purity of 95 wt% or more,
High frequency melting in Ar was performed using electrolytic Fe and ferroboron to obtain an alloy ingot having a composition such as 3.5 at% Nd-18.5 at% B-balFe. Next, this ingot was subjected to a heat treatment at 1000 ° C. for 24 hours in an Ar atmosphere. After remelting this ingot in an Ar atmosphere, a copper roll rotating at a high speed (roll surface speed 5 m
/ S to 50 m / s) to obtain an amorphous powder. The obtained powder is heated from room temperature to 850 ° C. under hydrogen at atmospheric pressure.
And hold it for 1 hour.
After forcibly evacuating to 0 ^-6 torr and holding for 1 hour, Ar
Quenched to room temperature.

Next, the quenched ribbon powder treated as described above
The powder was pulverized to 50 μm or less, the powder was oriented in a DC magnetic field of 30 kOe, fixed with paraffin, and the magnetic properties of the alloy powder were measured using VSM.

Example 2 Nd having a purity of 95 wt% or more,
High frequency melting was performed in Ar using electrolytic Fe and ferroboron to obtain an alloy ingot having a composition of 12.6 at% Nd-6.0 at% B-balFe. Next, this ingot was subjected to a heat treatment at 1000 ° C. for 24 hours in an Ar atmosphere. After remelting this ingot in an Ar atmosphere, a copper roll rotating at high speed (roll surface speed 5 m /
s to 50 m / s) to obtain an amorphous powder.
The resulting powder was heated to 850 ° C. from room temperature under atmospheric pressure of hydrogen, after the one hour hold, ^10-6 in the furnace by a vacuum pump
After forcibly evacuating to torr and holding for 1 hour, the mixture was rapidly cooled to room temperature in Ar.

Next, the quenched ribbon powder having been subjected to the above-mentioned treatment is mixed with 1
The powder was pulverized to 50 μm or less, the powder was oriented in a DC magnetic field of 30 kOe, fixed with paraffin, and the magnetic properties of the alloy powder were measured using VSM.

Comparative Example 1 3.5 at% Nd-18.5a
An ingot having a composition of t% B-balFe was subjected to a heat treatment at 1000 ° C. for 24 hours in an Ar atmosphere, and the ingot was redissolved in an Ar atmosphere. Then, a copper roll rotating at high speed (roll surface speed 5 m / s to 50 m / s). ) To obtain an amorphous powder. Using this powder, the magnetic properties were measured in the same manner as in Example 1.

Comparative Example 2 12.6 at% Nd-6.0a
An ingot having a composition of t% B-balFe was subjected to a heat treatment at 1000 ° C. for 24 hours in an Ar atmosphere, and the ingot was redissolved in an Ar atmosphere. Then, a copper roll rotating at high speed (roll surface speed 5 m / s to 50 m / s). ) To obtain an amorphous powder. Using this powder, the magnetic properties were measured in the same manner as in Example 1.

Comparative Example 3 12.6 at% Nd-6.0a
An ingot having a composition of t% B-balFe was subjected to a heat treatment at 1000 ° C. for 24 hours in an Ar atmosphere, and the ingot was heated from room temperature to 850 ° C. under hydrogen at atmospheric pressure, and held for 1 hour. After forced exhaustion to 10 ⁻⁶ torr and holding for 1 hour, the mixture was rapidly cooled to room temperature in Ar and pulverized to 150 μm or less to obtain a powder. Using this powder, the magnetic properties were measured in the same manner as in Example 1.

Table 1 shows the results of Examples 1 and 2 and Comparative Examples 1 to 3.
It was shown to. The values of Br and (BH) _max are values obtained by converting the density of the powder sample to 100%.

[0025]

[Table 1]

According to Table 1, in the present invention, the quenched ribbon is heat-treated in hydrogen and subjected to forced dehydrogenation to obtain Br, (BH).
_It can be seen that _max is improved. Further, it can be seen that the magnetic properties are improved by the additional elements such as Ga.

In this embodiment, the additive element is G
Although only a single addition of a, Zr, Cr, V, and Al is described, Si, Ti, and the like can be used, and the same effect can be obtained by adding them in combination.

(Embodiment 3) Nos. 1 and 3 of Embodiment 1
Using the amorphous powder of Example 2 and a heat treatment in hydrogen and a dehydrogenation treatment in a unidirectional magnetic field.

That is, the amorphous powders of Nos. 1, 3 and 2 of Example 1 were heated from room temperature to 850 ° C. under hydrogen at atmospheric pressure in a tubular core to which a DC magnetic field of 2000 Oe was applied in one direction. After heating and maintaining for 1 hour, the inside of the furnace was forcibly evacuated to 10 ⁻⁶ torr by a vacuum pump, and after maintaining for 1 hour, rapidly cooled to room temperature in Ar. The results are shown in Table 2. For comparison, a case where no magnetic field is applied is also shown.

(Table 2)

From Table 2, it can be seen that the powder subjected to heat treatment and dehydrogenation treatment in hydrogen while applying a magnetic field in one direction is different from the powder subjected to heat treatment and dehydrogenation treatment in hydrogen without application of a magnetic field.
It turns out that it shows excellent magnetic characteristics.

[0032]

According to the present invention, it is possible to provide a method for producing anisotropic polymer composite type rare earth magnet powder having a large Br and (BH) _max and excellent magnet properties.

Claims (3)

[Claims] 1. An RTB-based polymer composite type rare earth magnet powder (R is a rare earth element containing Nd as a main component and containing Y, 2.0 <R <13.5 at%, T is Fe , Co is a transition metal containing 70.0 <T <89.0 at%, B
Is 4.0 <B <20.0 at%).
-Liquid quenching of the TB-based alloy to obtain an amorphous powder,
A method for producing a powder for a polymer composite type rare earth magnet, comprising subjecting the powder to a heat treatment in hydrogen at 650 ° C. to 1000 ° C., and further performing a dehydrogenation treatment at 650 ° C. to 1000 ° C. 2. An RTBM-based polymer composite type rare earth magnet powder (R is a rare earth element containing Nd as a main component and containing Y, 2.0 <R <13.5 at%, T Is a transition metal containing Fe and Co as main components, 70.0 <T <89.0 at%,
B is 4.0 <B <20.0 at%, M is Ga, Zr, S
i, at least one of Cr, Ti, V, and Al)
In the production method, the RTBM alloy is rapidly quenched with a liquid to obtain an amorphous powder.
A method for producing a powder for a polymer composite type rare earth magnet, comprising performing a heat treatment in hydrogen at 0 ° C. and further performing a dehydrogenation treatment at 650 ° C. to 1000 ° C. 3. The method for producing a polymer composite type rare earth magnet powder according to claim 1, wherein the heat treatment in hydrogen and the dehydrogenation treatment are performed in a unidirectional magnetic field of 100 Oe or more. Method for producing powder for molecular composite rare earth magnet.