JPH01211902A - Manufacture of bonded magnet of rare earth, transistion metal, and boron - Google Patents

Abstract

PURPOSE:To improve characteristics of an anisotropic magnet, by quenching a molten R-T-B(rare earth-transistion mental-boron) alloy for producing a thin strip or piece, adding a binding material to magnetic powder obtained from the strip and shaping the mixture in an orientated magnetic flux. CONSTITUTION:Molten R-T-B alloy 53 substantially consisting of R2T14B is ejected toward the peripheral cooling surface of cooling rolls 54, 55 rotating at a predetermined rate so that the molten alloy is quenched and formed into a thin strip or piece 56. The thin strip is ground to produce magnetic powder having an average particle size smaller than the thickness of the thin strip or piece of the alloy 56. The magnetic powder thus obtained is heat-treated and a binding agent is added thereto. The mixture is shaped in an orientated magnetic field. In this manner, an R-T-B bonded magnet having anisotropy and thus-improved magnetic characteristics can be obtained.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to rare earth-transition metal-boron (R-T-B) permanent magnets, and particularly relates to rare earth-transition metal-boron (R-T-B) permanent magnets. The present invention relates to a method for manufacturing a bond type permanent magnet with excellent anisotropy.

[Conventional technology]

For conventional R-T-B permanent magnet alloys, N, C, K
Appl, PHYS, by OOn and B, N, DaS et al.
Lett, 39(10) 1981°840 (Reference text M1), (F e o, azBo, +a)
The magnetic properties of amorphous and crystallized alloys of o, e T b o, osL ao, os are disclosed, and the crystallization of the alloy occurs at a relatively high temperature of around 900' K, and the inherent coercive force It has been shown that a significant increase in the number of

It also suggests that the crystalline alloy is useful as a low-cobalt permanent magnet.

J. J. Croat describes an amorphous R-Fe-B (Nd or Pr is particularly useful for R) alloy in JP-A-59-64.
As disclosed in Publication No. 739 (Reference 2),
It is proposed because it has the magnetic characteristics of a permanent magnet.

References 2 and 3 disclose the use of transition metal elements other than Fe as Fe substitution trees.

These magnetic properties were thought to be due to the microstructure in which Nd2Fe+4B magnetic crystal grains having a grain size of 20 to 400 n1m were dispersed in an amorphous iron phase. For more details, please refer to R., Hishra's J. nagnetisn.
+and Hagnetic Materials,
54-57 (1986) 450 (Reference 4).

On the other hand, regarding the manufacturing method of rapidly solidified alloy ribbon, for example, Ega
Journal of The ii
An+eri-can Ceraiic 5ociet
y, Vol. 60. No, 3-4. Mar, -Apr.

1977, p, p, 128-133 (Reference 5
)'Low-FieldMagnetic Pro
party of＾norphous A11ays
(Low-field magnetic properties of amorphous alloys)'' and uses a continuous splat quenching method.

A similar continuous splat quenching process is disclosed in references 2 and 3 as the "melt vinyl quenching process."

That is, molten RT-8 alloy is injected through a small orifice onto the cooled outer peripheral surface of a rapidly rotating copper chill roll.

The molten alloy is quenched by the disk to form a quenched ribbon. Therefore, amorphous alloys form at relatively high cooling rates and crystallize at relatively low cooling rates.

According to References 2 and 3, the main limiting factor regarding the cooling rate of the alloy ribbon on the cooling surface of the outer peripheral surface of the chill roll is the thickness of the alloy ribbon. That is, if the ribbon is very thick, the metal furthest from the cooling surface cools very slowly and crystallizes out in a soft magnetic manner. Therefore, when an alloy ribbon is cooled very quickly, the ribbon exhibits a microstructure that has a combination of almost completely amorphous areas and highly 1y1481 crystalline areas. Therefore, the free surface part of the alloy ribbon that is farthest from the cooling surfaces 3 and 4 is crystallized because it is cooled more slowly.
On the other hand, the crystal surface that comes into contact with the cooling surface rarely crystallizes because it cools quickly.

As a result, the grain size of the crystal grains differs depending on the thickness of the ribbon.

References 2 and 3 describe materials in which the grain size is substantially uniform across the thickness of the ribbon, rather than materials that exhibit substantial variation in grain size across the thickness of the ribbon. This indicates that certain magnetic materials tend to exhibit better permanent magnetism.

In order to manufacture such a practical magnet, a rapidly solidified alloy ribbon was pulverized to form a bonded magnet. References include a lecture given by R.W. Lee et al. at the International Society of Magnetics, held on April 29, 1985 in St. Pau I, Minnesota, and IEEE Magnetics Society Bulletin MAG Volume 21, No. 5, 1985.
“Processing of NeodyIlliul” published in November 1985 (referred to as #Reference 6)
-Iron-Boron Melt-8pun Rib
bonsTo Fully Dense Hagnet
”.

Generally, Nb-Fe-B rapidly solidified alloys have been able to produce only isotropic magnets due to their crystallographic isotropy. This means that it is impossible to obtain a bond type high-performance anisotropic magnet from a rapidly solidified alloy.

Therefore, in Reference 6, the bonded magnet is 9M G O
It has been shown to have an energy product of e or less.

Further, Reference 6 shows that the magnetic field orientation is significantly enhanced by subjecting a Hola Mill press sample of powdered and crushed alloy ribbon to sufficiently dense upsetting.

JP-A-60-89546 (Reference Document 7) discloses a quenched R-Fe-B permanent magnet alloy having a high coercive force. This alloy is dominated by hexagonal crystals of less than 5 μm.
The 100 tile mesh (300 μm) has a very fine composite structure and is used in the production of bonded magnets.
) is ground into a powder with a particle size of:

[Problem to be solved by the invention]

However, although Reference 7 indicates that C-axis anisotropy was confirmed by applying an X-ray diffraction microscope to the alloy surface, it does not mention anything about bonded magnets. Magnetic field orientation cannot actually be obtained with this ground powder.

On the other hand, for sheets, etc., anisotropic R-Fe manufactured from an alloy ingot of R (particularly Nd), Fe, and B by a normal powder metallurgy method is disclosed in JP-A-59-46008 (reference document 8). -B sintered magnet was proposed. However, R-
Fe-B alloys have the disadvantage of being easily oxidized during magnet manufacture.

This is because the R-Fe-B alloy ingot consists of the compounds R, Fe, . In view of the above-mentioned drawbacks, the technical problem of the present invention is to provide a rare earth metal with anisotropy and excellent magnetic properties.
An object of the present invention is to provide a method for manufacturing an iron-boron bonded magnet.

[Means for Solving the Problems] According to the present invention, R-1'-B consisting essentially of R2'f', , B (R represents a rare earth element and T represents a transition metal)
A method for producing a rare earth-transition metal-boron bonded magnet in which magnetic powders of an alloy are bonded to each other by a binder includes a molten alloy preparation step of preparing the R-T-B alloy in a molten state, and quenching the molten alloy. to produce an R-T-B ribbon or flake containing R2T14B crystal grains;
The thickness of the alloy ribbon or flake is substantially 20 to 1000 μm.
a pulverizing step of pulverizing the R-T-B alloy ribbon or flake to produce magnetic powder; a mixing step of mixing the magnetic powder with the binder to produce a mixture; A method for producing a rare earth-transition metal-boron bonded magnet is obtained, which comprises a magnetic field forming step of forming a mixture in an oriented magnetic flux to produce a compact.

The magnetic powder is formed to have an average particle size smaller than the thickness of the alloy ribbon or flake.

Further, according to the present invention, a rare earth-transition metal characterized in that, before the mixing step, a magnetic powder heat treatment step is provided in which the magnetic powder is heat-treated at a temperature of substantially 500 to 700°C. - A method for manufacturing a boron bonded magnet is obtained.

According to one aspect of the present invention, before the pulverizing step, the R-
The T-B alloy ribbon or flake is heated to substantially 650 to 950°C.
Rare earths - transition metals - characterized in that they are subjected to an R-T-B alloy ribbon or flake heat treatment process without being heat-treated within the range of
A method for manufacturing a boron bonded magnet is obtained.

According to one aspect of the present invention, the quenching step includes spouting the molten alloy onto the outer circumferential cooling surface of a cooling roll member rotating at a predetermined speed, rapidly cooling the spouted molten alloy, and -T-B ribbons or flakes are produced; preferably, the quenching step includes applying a magnetic field in the radial direction of the quench roll member to quench the ejected molten alloy; shall be.

Preferably, the quenching step includes providing a plurality of protrusions on the outer peripheral cooling surface of the cooling roll member, and arranging a cooling plate member adjacent to the cooling roll member. The method is characterized in that the molten alloy ejected onto the outer circumferential cooling surface is sprayed onto the cooling plate member to generate the flat R-T-B flakes.

Preferably, in the quenching step, the cooling roll member has first and second cooling roll parts, and the molten metal is jetted onto an outer circumferential cooling surface of the first roll part, and the jetted metal is The molten alloy is rapidly cooled to produce an R-T-B alloy ribbon, and then the free surface of the R-T-B alloy ribbon is rapidly cooled on the outer peripheral cooling surface of the second cooling roll section, A method for producing a rare earth-transition metal-boron bonded magnet is obtained, which is characterized by producing a rapidly solidified RTB alloy ribbon.

Furthermore, according to the present invention, the quenching step is characterized in that the molten alloy is sprayed from a spray nozzle to powder, and then rapidly cooled on a cooling plate surface to produce the flat R-T-B flakes. A method for producing a rare earth-transition metal-boron bonded magnet is obtained.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings.

An alloy ingot consisting of 32.0 wt% R, 1.1 wt% B, and the balance substantially Fe was produced by high-frequency heating and melting in an argon gas atmosphere. The raw materials used for RlB and Fe have a purity of 97% and are mainly composed of Ce and P.
The ingot was melted again in a zero-order argon gas containing Nd containing a rare earth metal element of r, ferroboron containing 20% B, and electrolytic iron. The alloy is injected through a small diameter orifice onto the cooling outer surface of a steel cooling roll rotating at various cooling surface speeds from 1 m/Sec to about 50 m/sec and having various widths from 1 to 15III11 and 10
μm, 20 μm, 50 μm, 100 μm, 200 μm,
Rapidly solidified alloy ribbons having various thicknesses of 500 μm, 11000 cz, and 2000 μm were produced.

X-ray diffraction microanalysis of these ribbons revealed that the fine particles R2F
It was found that e, B crystal particles were dispersed in the ribbon. These crystal grains primarily have a grain size of about 3 μm or less in each ribbon having a thickness of 200 μm or less, and approximately 10 μm or less in a ribbon having a thickness of 500 μm. , 20
In ribbons with a thickness of 0.00 μm, the grain size was approximately 30 μm or smaller.

That is, as the thickness of the ribbon increases, the grain size of the crystal grains increases. Furthermore, X-ray diffraction microanalysis revealed that the 0 plane in the quenched R-Fe-B alloy ribbon tends to be oriented parallel to the main plane of the ribbon when the grain size is 5 μm or smaller. be.

As the crystal grains grow larger than 5 μm, the crystals become needle-like, and the zero plane of the crystals is oriented perpendicular to the main plane of the ribbon.

Such ribbons with different thicknesses are then individually ground and ground in a ball mill, each having a thickness of 15 μm.
The powder had an average particle size of m.

Each powder was mixed with a binder epoxy resin to form a mixture.

The total amount of epoxy resin is 25 VOI% of the mixture. This mixture has a pressure of 30 KO at a pressure of 5 ton-f/a+1.
The powder was compacted in a magnetic field of e to form a compact. The formations were treated at 110° C. for 1 hour to cure the epoxy resin to form the bonded magnets.

Then, the magnetic properties of the bonded magnet were measured after being placed in a magnetic field of 30 KOe and magnetized.

Figure 1 shows the measured magnetic properties.

Figure 1 shows that (BH) higher than 9MGOe□8 when using a ribbon with a thickness of 20 μm or more.
This shows that it gives an energy product of , and gives a high residual magnetic flux density Br.

However, the coercive force, Hc, also increases with increasing ribbon thickness up to 100 μm, but decreases when the ribbon thickness exceeds 100 μm, and becomes extremely small at 2000 μm. Become. Therefore, the thin strip is 20~1000μ
Preferably, it has a thickness of m.

K ship■yu 20 μm each, prepared in the same manner as in Example 1.

Powders were prepared from ribbons with thicknesses of 100 μm and 1000 μm. These powders were prepared in an argon atmosphere for 4 hours.
After heat treatment at 50 to 750° C. for 1 hour, bonded magnets were formed from each powder as compacts in the same manner as in Example 1, and the magnetic properties were measured. The measured magnetic properties are shown in FIG. In FIG. 2, the broken line A is
Represents the magnetic properties when using a 1000 μm thick alloy ribbon, - dotted line B is a 100 μm thick ribbon, and solid line C is 2
It shows the magnetic characteristics when using a thin ribbon with a thickness of 0 μm.

From Fig. 2, IHC was improved by heat treatment of the powder at 500-700°C, while (BH).

and Br generally do not change even with heat treatment.

On the other hand, R is 35.0wt%, B is i, oIAt%, and Co is 71
Example 1 An alloy ingot consisting of At% and balance Fe was prepared in Example 1.
It was produced in the same manner as.

The raw materials for R are 5 wt% Ce, 15 wt% Pr, and cerium dididium, the balance of which is substantially Nd, and 5 at% D.
y is added. Ferroboron and electrolytic iron were used as raw materials for B and Fe.

The ingot was remelted and injected onto the peripheral cooling surface of a roll rotating at a cooling surface speed of 50 m/sec to produce a quenched alloy ribbon approximately 21111 wide and 15 μm thick. Similarly, another one about 10m wide, 200μ thick
m2 of cooled alloy ribbon was produced at a cooling surface velocity of 5 m/sec.

X-ray diffraction reveals that the 15 μm thick ribbon has an R
It contained T 148 (T=Co+F e ) crystal grains and had a submicron particle size.

On the other hand, the 200 μm thick ribbon had mainly grain sizes of 5 μm or smaller, with the zero plane of the crystals also oriented parallel to the major surface of the ribbon.

In the same manner as in Example 1, these ribbons with a thickness of 15 μm and a thickness of 200 μm were respectively ground into powders. And each powder has an average particle size of 10 μm. Each powder was heat treated at 650° C. for 1 hour in an argon atmosphere.

Each powder has a volume of 40Vo when mixed.
It was mixed with a polyethylene binder at a concentration of 1%.

The mixture was heated at 100° C. to melt the polyethylene and injected into a mold at about 100° C. in a 20 KOe orienting magnetic field to form a bonded magnet of the desired shape. Table 1 shows the magnetic properties of the obtained bonded magnet.

From this Table 1, the one using a 200 μm thick ribbon is:
It can be seen that it provides superior magnetic properties compared to a ribbon with a thickness of 15 μm.

K Hemostasis 1 A quenched ribbon having a width of 511n+ and a thickness of approximately 50 μm was prepared from the ingot prepared in Example 1 by using a copper roll rotating at a cooling surface speed of 10 m/sec.

By X-ray diffraction microanalysis, it was observed that the fabricated ribbon had crystal grains primarily of 1 μm or smaller size.

These crystal grains have a C-plane orientation parallel to the main plane of the ribbon, and the C-plane orientation is exposed to the atmosphere compared to the cooling surface layer of the ribbon that is in contact with the cooling surface at the disk outer periphery. The free surface layer side is predominant.

Then, the ribbon was heated at 600°C and 700°C in an argon atmosphere.
Heat treatment was performed at 1800°C, 900°C, and 1000°C for 2 hours each. They were then individually milled using a ball mill into powders each having an average particle size of 15 μm.

Each powder was then mixed by volume with an epoxy resin containing 25 VO 1% and compression molded into a compact at a pressure of 5 ton-f/clIl in an oriented magnetic field of 30 koe.

The molded body was then heat treated at 110° C. for 1 hour to form a bonded magnet.

The magnetic properties of the obtained bonded magnet were measured by placing it in a magnetic field of 30 kOe. The measured magnetic properties are shown in FIG.

From FIG. 3, it can be seen that Br, (BH), and - were improved by heat treatment of the powder. Therefore, the heat treatment temperature is 650~
Preferably, it is selected within a temperature range of 950°C.

Example 3 A rapidly solidified alloy with a width of 10 mm and a thickness of about 100 μm
was made from an ingot using a chilled copper roll.

The ribbon was found to contain primarily crystal grains of size 3 μm or smaller with a C-plane orientation parallel to the major plane of the ribbon.

Then, in the same manner as in Example 4, the ribbon was heat treated at 800° C. for 1 hour in an argon atmosphere, and then ground into particles with an average particle size of 10 μm.

The powder was further heat treated at 550° C. for 10 hours in an argon atmosphere. Thereafter, 40vo1% polyethylene and the remaining powder were mixed together and heated at 100°C to produce 20KOe.
was ejected in an orienting magnetic field.

In this way, a bonded magnet was manufactured. The magnetic properties of the bonded magnets are shown in Table 2 along with magnets made from powder without heat treatment.

Table 2 Table 2 shows the results of heat treatment of ribbon and powder.
Although the powder shows slightly lower HC than the powder without heat treatment, Br and (B H). , shows that these treatments improve performance.

In the same manner as in Example 1, Nd with a purity of 97% and Nd
using the raw materials of Y, ferroboron, electrolytic iron, and electrolytic cobalt, R is 35.0-1% and B is 1%.
．． 0 revision%, remainder T-Fe+-g Cow (x=0.
0.1, 0.2'.

0.3, 0.4, 0.5) were melted in the same manner as in Example 1, and injected onto the cooling surface of the outer periphery of a copper cooling roll rotating at a surface speed of 5 m/sec.
A rapidly solidified alloy ribbon having a thickness of 200 μm was formed.

X-ray diffraction microanalysis revealed that each of the obtained rapidly solidified alloy ribbons contained fine grains R2 with a large proportion of C-plane orientation in the preferential direction.
It was observed that it contained T14B crystal grains.

Each alloy ribbon was ground into a powder with an average particle size of 10 μm, and then heat treated at 650° C. for 1 hour in an argon atmosphere.

Each of the powders and 40vol% polyethylene were mixed together, melted at 100° C. in an oriented magnetic field of 20KOe, and injection molded to form a bonded magnet.

In this way, bonded magnets with different cobalt contents were produced and their magnetic properties were measured after being placed in a magnetic field of 30 K Oe.

The measured magnetic properties are shown in FIG.

From FIG. 4, it can be seen that partial replacement of Fe with Co up to 45 at% helps to improve Br and (BH).

R is 33.0wt using the same raw materials as those in Example 3.
%, B is 1.014°C%, remainder T=F e 6. g,
An alloy ingot consisting of cO6,1 was produced in the same manner as in Example 3. Furthermore, R33, OWT%, B1
．． Another ingot consisting of 0 wt%, balance iron was also prepared. From each of these ingots, 1011
An alloy ribbon having a width and thickness of approximately 100 μm was prepared by a continuous splat cooling method using a cooling roll rotating at a cooling surface speed of 8 m/sec. The obtained ribbon was observed by X-ray diffraction microanalysis. As a result, the cobalt-containing ribbon was found to have a higher proportion of C-plane orientation in the preferred direction compared to other ribbons not containing cobalt.

These ribbons were ground into powders each having an average particle size of 15 μm, followed by heat treatment at 650° C. for 1 hour in an argon atmosphere. Then, each powder was mixed with epoxy resin in an amount of 25 vol% of the mixture and 5 ton-f/a in an orienting magnetic field of 30 KOe.
It was made into a molded body by the pressure of d. This molded body is 110
℃ for 1 hour to form a bonded magnet.

A bonded magnet was manufactured in this way, magnetized by applying a magnetic field of 30 KOe, and then its magnetic properties were measured.

Table 3 shows the measured magnetic properties.

Table 3 Table 3 shows that replacing a portion of iron with Co improves Br and (BH), while slightly decreasing +HC.

X-ship Ritama ferroboron, electrolytic iron, and mainly Pr with a purity of 97%
, Nd containing Ce and not adding 10 at% of Dy and Pr
R is 34.0 wt%, B is 1.0 wt%, T
-Feo, 6sCoo, and 3s alloy ingots were prepared in a manner similar to that described in Example 1.

From this ingot, alloy ribbons with a width of 3 nl and a thickness of 30 μm were prepared by a similar continuous splat cooling method using copper cooling rolls rotating at a cooling surface speed of about 15-m/sec. One of the ribbons was exposed to a magnetic field during quenching.

FIG. 5 shows an apparatus used to fabricate ribbons while applying a magnetic field.

This device consists of a melting tube 21 made of quartz, for example, in which the alloy ingot is melted.

The melting tube 21 has an orifice portion 22 with a small diameter,
Through it, the molten alloy 23 is injected onto a cooling roll 24 made of iron. Two hollow disc-shaped cases 25 and 25' are provided on opposite sides of the cooling roll 24, and have rotating shafts 26 and 26' on a common axis.

Cases 25 and 25' are disk-shaped permanent magnets 2T and 2T'.
The permanent magnets 2T and 2T' are magnetized in the thickness direction and have the same magnetic pole faces close to opposing surfaces of the cooling roll. The magnetic flux from both permanent magnets 2T and 2T' flows radially on the outer peripheral surface of the iron cooling roll.

In this embodiment, the permanent magnets 2T and 2T' are disk-shaped samarium and cobalt magnets, which are IK
It has a Gaussian surface magnetic flux density, a diameter of 20 ann, and a thickness of 2.5 cm.

As the cooling roll 24, an iron disc having a diameter of 21'co and a thickness of 20 cm is used.

A magnetic field of about 3 KOe was observed on the outer peripheral surface.

Since the rotating shafts 26 and 26' are rotated at the same time, the outer peripheral surface of the cooling disc roll 24 is 15 m/Sec.
The molten alloy 23 passes through the orifice portion 22 and is injected onto the outer peripheral surface of the cooling roll 24. The ribbon is therefore placed in the radiating magnetic field of the roll, so that the magnetic field is applied to the ribbon in the thickness direction while it is being cooled. On the other hand, a comparative example was prepared using an apparatus in which only the permanent magnets 2T and 2T' were replaced with non-magnetic disks. Therefore, a magnetic field is hardly applied to the thin ribbon of the comparative example.

It was confirmed by X-ray diffraction microanalysis that these ribbons had fine crystal grains of 1 μm or smaller.

Furthermore, it was confirmed that the ribbons to which this magnetic field was applied had more C-plane crystals oriented parallel to the principal plane of the ribbon than those to which no magnetic field was applied. Ta.

These ribbons were ground into powders with an average particle size of 10 μm and heat treated at 550° C. for 20 hours in an argon atmosphere.

Then, 40vo1% polyethylene and each powder were mixed with each other, and in an orienting magnetic field of 20KOe, about 100%
It was injection molded at ℃ to form a bonded magnet. The magnetic properties of each of the obtained bonded magnets are shown in Table 4.

Table 4 shows that the magnetic properties of the bonded magnets were significantly improved by preparing rapidly solidified alloys formed by applying a magnetic field in the thickness direction.

From the same raw materials as in Example 3, R35, O, old%, Bo,
Example 1 An alloy ingot containing 914°C% and the balance Fe
It was made in the same way as.

A rapidly solidified alloy ribbon having a width of about 2 and a thickness of about 15 μm was produced from the ingot in the same manner as in Example 1 using a continuous splat cooling method using an iron cooling roll.

On the other hand, a rapidly solidified alloy flake having a diameter of about IIn and a thickness of 15 μm was prepared using the apparatus shown in FIG. 6(a).

It can be seen in FIG. 6(a) that the apparatus produces rapidly solidified alloy ribbons or flakes with improved uniform orientation of the crystals. This device has, for example, a quartz melting tube 31 having an orifice portion 32 with a small diameter, so that the molten alloy 3
3 is injected through an orifice 32 onto the outer cooling surface of a cooling roll 34 rotating at a predetermined speed.

The cooling surface of the cooling roll 34 is provided with two adjacent protrusions 35 as shown in the enlarged cross-sectional view of FIG. 6(b).

In this embodiment, the protrusion 35 has a height of 0.5 nI and a height of 11
It is formed with a pitch of 111. A circular cooling plate 37 having a rotating shaft 38 is arranged adjacent to the cooling roll with its main surface facing the cooling surface of the cooling roll 34 .

The alloy ingot is melted and injected onto the cooling surface of chill roll 34. The injected molten alloy is sprayed onto the main surface of the circular cooling flat plate 37 as powdered granules on the main surface of the protrusion 35, where it collides and deforms into flat pieces forming quenched strips.

The ribbon and 10 pieces are crushed, each 10 μm.
The result is a powder with an average particle size of . And the powder is 650℃
The sample is heat treated in an argon atmosphere for 1 hour.

Each powder is then mixed with polyethylene in an amount of 40vol% of the mixture. This mixture was heated to 100°C.
It was poured into a mold in an orienting magnetic field of 20 K Oe to form a bonded magnet.

In this way, bonded magnets were manufactured, and the magnetic properties of the magnets are shown in Table 5.

Margin below Table-5 Table 5 shows the magnet properties, especially Br and (BH).

It can be seen that the use of the quenched alloy thin strip produced by the apparatus shown in FIG. 6(a) was better than that of the alloy thin strip produced by the usual continuous splat quenching method.

cause j111”.

An alloy ingot consisting of 32.0 wt% R, 1.0 wt% B, and the balance Fe was produced using the same raw materials and melting method as in Example 1. Ten granules or globules having a particle size of about 0.21111 were made from the ingot by known milling methods, while having a diameter of about 0.31 and a diameter of about 100 μm.
Ten thin sections having a thickness of m were prepared using the apparatus shown in FIG.

Referring to FIG. 7, the device consists of a quartz melting tube 1, with a spray nozzle 42 arranged in the lower part of the melting tube 41.

The alloy is melted in the melting tube 41, and the molten alloy 43 is sprayed as powdered particles P from the spray nozzle 42 by introducing argon gas into the spray nozzle 42. In the known atomization process, the powdered molecules are transformed into small round balls or granules.6 In the apparatus shown in the figure, a copper cooling plate 44 is placed below the nozzle 42 and rotated.

Before the powdered particles P are cooled and hardened, they are placed on a cooling flat plate 44.
collides with the main surface of It is then deformed and cooled into flat flakes.

The granule alloy and the flake alloy were subjected to Xfa diffraction microanalysis, and the former showed R2Fe with 0-faces oriented in various directions;
, B crystals, in the latter the 0-plane has a 0-plane preferred direction in the parallel direction near the cooling surface of the cooling plate, and the free surface layer of the flake alloy has crystal grains in the direction perpendicular to the cooling surface. Contains some slightly oriented parts.

10 pieces of granular alloy balls and 10 pieces of flakes were ground into powder with an average particle size of 15 μm and heated for 6 hours for 1 hour.
Heat treatment was performed at 50° C. in an argon atmosphere.

Each of the powders is mixed with 25 VO 1% epoxy resin and molded into a compact at a pressure of 5 tOn-f/cd in an orienting magnetic field of 30 KOe. Then, the molded body was heated to 110°C.
After being heat-treated for one hour, it becomes a bonded magnet. In this way, the bonded magnet is manufactured and the magnetic properties are measured. The measured properties are shown in Table 6.

Table 6 Table 6 shows that by using the quenched flakes prepared by the apparatus shown in Figure 7, the magnetic properties are improved compared to the quenched granular particles prepared by the normal powdering method. Ta.

Dog JLLLL Using an ingot produced in the same manner as in Example 3, rapidly solidified alloy granules having an average particle size of about 30 μm were produced by a normal atomization method. Rapidly solidified alloy pieces having an average grain size of about 0.11 Il and an average thickness of about 50 μm were then prepared again using the apparatus of FIG. 7 in a manner similar to that shown in Example 10. X-ray diffraction microanalysis reveals that the flake alloy has R 2 oriented in a direction parallel to the 0-plane.
It was confirmed that it had T14B crystals. On the other hand, the granular alloy also has R2T +4B crystal grains, but with the 0-face oriented in a different direction. 10 pieces of granules and 10 pieces of flakes were ground into powders each having an average particle size of 10 μm, and heat treated using the same heat treatment method as in Example 10. Add 40% of each powder to the mixture
Mixed to contain vo1% polyethylene, 1
Injected into a mold in an orientation magnetic field of 20KOe at 00℃,
Becomes a bonded magnet. The magnetic properties of the obtained bonded magnet are shown in Table 7.

From Table 7, it was found that the use of rapidly solidified alloy flakes significantly improved the magnetic properties compared to that of rapidly solidified alloy granules.

An ingot consisting of 32.0141% x1R, 1.0% B, and the balance Fe was produced using the same raw materials and method as described in Example 1.

Then, quenched alloy ribbons of different thicknesses were produced using the quenched alloy manufacturing apparatus shown in FIG.

Turning to FIG. 8, the apparatus shown therein includes a melting tube 5 made of, for example, quartz, having an orifice portion 52 at the bottom.
6 alloys, which are found to contain 1, are melted in the melting tube 51 as indicated by the reference numeral 53. A first cooling roll 54 is disposed below the orifice portion 52 and cools the molten alloy 53.
is injected onto the outer circumferential cooling surface of the cooling roll 54 through the orifice portion 52. Another second cooling roll 5
5 is disposed close to the first cooling roll 54 with a small gap from the cooling surface. First and second rolls 54
．． 55 rotate in opposite directions at the same rotational speed.

The molten alloy injected from the orifice portion 52 is formed into a ribbon shape onto the cooling surface of the first roll 54 , and then the free surface of the ribbon 56 connects the surface to the outer surface of the second roll 55 . Contact.

The free surface of the ribbon 56 is therefore quenched by the second roll 55.

In the prior art, the method of using two cooling rolls is a well-known method for forming an amorphous alloy ribbon (hereinafter, this method will be referred to as the "twin roll method"). In the twin roll method, referring to FIG. 8, the molten alloy 53 is injected directly between two rolls 54 and 55, so that the molten alloy is rapidly cooled from both sides simultaneously.

Although the apparatus shown in FIG. 8 uses two rolls similar to the twin roll method, the molten alloy is not cooled simultaneously, but contacts the two rolls at different times. therefore,
The present method using the apparatus shown in FIG. 8 will be referred to as the "modified twin roll method". Approx. 1m/sec to approx. 5
The rotational speed of the cooling surfaces of the first and second rolls 54 and 55 is 0 m/sec, the thickness is controlled to be 10 μl to 2000 μm, and the width is controlled to be 0.5 to 20 μm.

As a comparative example, rapidly solidified alloy ribbons with different thicknesses varying within a similar range were prepared by each of the single roll method and the twin roll method.

These ribbons were observed by xi diffraction microanalysis,
And they were found to have Nd2Fe+J crystal grains.

Furthermore, in a ribbon of increased thickness, the number of crystals oriented or aligned perpendicular to the 0-plane or some direction increases.

The C-plane orientation changes from a direction horizontal to a direction perpendicular to the main surface of the ribbon as the noisiness of the ribbon increases.

These ribbons are then crushed, each with an average particle size of 1
The result is 5 μl of powder. Each powder is heat treated at 650° C. for 1 hour in an argon atmosphere and mixed with epoxy resin representing 25 vol% of the mixture.

The mixture is compacted into a compact in an orienting magnetic field of 30 KOe at a pressure of 5 ton=f/cJ.

The compression molded body is heat treated at 110° C. for 1 hour to become a bonded magnet. The magnetic properties of this bonded magnet were measured by placing it in a magnetic field of 30 KOe.

The magnetic properties of the bonded magnet thus obtained are shown in FIG. In Fig. 9, the broken line A indicates the magnetic properties of the magnet obtained using the ribbon produced by the modified twin-roll method, the dashed line B indicates the magnetic properties of the magnet obtained using the conventional twin-roll method, and the solid line C indicates the ribbon obtained by the single-roll method. The characteristics of the magnet used are shown.

From FIG. 9, it can be seen that the use of the ribbon produced by the modified twin roll method provides higher magnetic properties than the ribbon produced by the conventional method.

The K-group quenched alloy ribbon has a thickness of about 500μl and a width of about 15I.
nIIl, this alloy was made from ingots prepared by the single roll method, twin roll method, and modified twin roll method of Example 3.

X-ray diffraction microanalysis revealed that these ribbons also had a similar grain structure to ribbons such as Example 12.

These ribbons were ground and formed into powders each having an average particle size of 10 μl. Each powder was heat treated at 650° C. for 1 hour in an argon atmosphere. And 40v
Mixed with o1% polyethylene, 20K at 100℃
A bonded magnet was formed by injecting it into a mold in an orienting magnetic field of Oe. The magnetic properties of the obtained bonded magnet are shown in Table 8.

According to Table 8, the bonded magnet obtained by the modified twin-roll method has better magnetic properties than any magnet made from a ribbon that cannot be obtained by the single-roll method or the conventional twin-roll method. turned out to be excellent.

[Effects of the Invention] As described above, according to the present invention, a rare earth-transition metal-boron bonded magnet having anisotropy and thus improved magnetic properties can be easily obtained.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the thickness and magnetic properties of the alloy ribbon used in the bonded magnet of Example 1 of the present invention. FIG. 2 is a graph showing magnetic characteristics with respect to the thickness of the alloy ribbon used in the bonded magnet of Example 2 of the present invention and the heat treatment temperature of the powder. FIG. 3 is a graph showing the relationship between the heat treatment temperature of the alloy ribbon used in the bonded magnet of Example 4 of the present invention and the magnetic properties. FIG. 4 is a graph showing the relationship between the Co content substituted for Fe and the magnetic properties of the bonded magnet. FIG. 5 is a sectional view of an apparatus for producing a rapidly solidified alloy ribbon used in implementation S8 of the present invention. FIG. 6(a) is a side view of an apparatus for producing rapidly solidified alloy flakes used in an embodiment of the present invention, and FIG. 6(b) is an outer peripheral surface of the cooling roll shown in FIG. 6(a). FIG. 7 is a cross-sectional view of the apparatus for producing rapidly solidified alloy flakes used in Example 10 of the present invention. FIG. 8 is a sectional view of an apparatus for producing a rapidly solidified alloy ribbon used in Example 12 of the present invention. FIG. 9 is a graph showing the relationship between the thickness of the alloy ribbon prepared by different quenching methods in Example 12 of the present invention and the magnetic properties of the bonded magnet. In the figure, 21 is a melting tube, 22 is an orifice part, 23 is a molten alloy, 24 is a cooling roll, 25° 25' is a disk-shaped gauge, 26.26' is a rotating shaft, 2T. 2T' is a disc-shaped permanent magnet, 31 is a molten tube, 32 is an orifice, 33 is a molten alloy, 34 is a cooling roll, 35 is a protrusion, 36 is a groove, 37 is a cooling flat plate, 38 is a rotating shaft, 41 is a A melting tube, 42 is a spray nozzle, 43 is a molten alloy, 44 is a cooling flat plate, 51 is a melting tube, 52 is an orifice portion, 53 is a molten alloy, 54 is a first cooling roll, and 55 is a second cooling roll. Fig. 1 Thickness of the quenched alloy ribbon 2 (μm) Fig. 2 Aging - AM (''c) Fig. 3 - Heat and treatment temperature of the quenched ribbon (°C) Fig. 4 Co substitution rate of Fa Fig. 5 Figure 16 (Q) Figure 8

Claims (24)

[Claims] 1. Substantially R_2T_1_4B (R is a rare earth element, T
represents a transition metal. ) A method for manufacturing a rare earth-transition metal-boron bonded magnet in which magnetic powder of an RTB alloy is dispersed and bonded to each other by a binder, the molten alloy preparing the R-T-B alloy in a molten state. a preparatory step; quenching the molten alloy to produce an R-T-B ribbon or flake containing R_2T_1_4B crystal grains;
The thickness of the alloy ribbon or flake is substantially 20 to 1000 μm.
A pulverizing step of pulverizing the R-T-B alloy ribbon or flake to produce magnetic powder; A mixing step of mixing the magnetic powder with the binder to produce a mixture; A method for producing a rare earth-transition metal-boron bonded magnet, comprising a magnetic field forming step of forming the mixture within an orientation magnetic flux to produce a compact. 2. The method of manufacturing a rare earth-transition metal-boron bond magnet according to claim 1, wherein the magnetic powder has an average particle size smaller than the thickness. 3. In the method for producing a rare earth-transition metal-boron bonded magnet according to claim 1, the quenching step comprises converting magnetic powder having an average particle size smaller than the thickness into a magnetic powder having an average particle size substantially in the range of 0.01 to 20 μm. R_2T_1_4 within
A method for producing a rare earth-transition metal-boron bonded magnet, comprising producing the R-T-B alloy ribbon or flake having B crystal grains. 4. The method for manufacturing a rare earth-transition metal-boron bonded magnet according to claim 1, wherein the molten alloy preparation step prepares the R-T-B alloy in which the transition metal is Fe. Method for manufacturing a metal-boron bond magnet. 5. In the method for manufacturing a rare earth-transition metal-boron bonded magnet according to claim 1, the molten alloy preparation step includes the R-T-B in which the transition metal is 45 at% or less Co and the balance Fe. A method for producing a rare earth-transition metal-boron bond magnet, which comprises preparing an alloy. 6. The method of manufacturing a rare earth-transition metal-boron bond magnet according to claim 1, wherein in the molten alloy preparation step, Nd is used as the rare earth element. 7. The method for producing a rare earth-transition metal-boron bond magnet according to claim 1, wherein the molten alloy preparation step uses cerium dididium added with the rare earth element Dy. Production method. 8. In the method for manufacturing a rare earth-transition metal-boron bond magnet according to claim 7, the cerium didymium contains 50
% Ce, 15% Pr, and the balance substantially Nd. 9. 9. The method of manufacturing a rare earth-transition metal-boron bond magnet according to claim 8, wherein the amount of Dy added is 5 at%. 10. The method for producing a rare earth-transition metal-boron bonded magnet according to claim 1, wherein, before the mixing step, a magnetic powder heat treatment step is performed in which the magnetic powder is heat-treated at a temperature substantially within a range of 500 to 700°C. A method for producing a rare earth-transition metal-boron bonded magnet. 11. In the method for producing a rare earth-transition metal-boron bonded magnet according to claim 1, before the pulverizing step, the R-T-B alloy ribbon or flake is substantially
A method for producing a rare earth-transition metal-boron bonded magnet, comprising a step of heat treating an R-T-B alloy ribbon or flake in a temperature range of 950°C. 12. The method for producing a rare earth-transition metal-boron bonded magnet according to claim 11, including a magnetic powder heat treatment step of subjecting the magnetic powder to heat treatment at a temperature of substantially 500 to 700° C. before the mixing step. A method for producing a rare earth-transition metal-boron bonded magnet. 13. The method for producing a rare earth-transition metal-boron bonded magnet according to claim 1, wherein the magnetic field forming step includes pressurizing the mixture in an orienting magnetic field to produce a compact. - A method for manufacturing a boron bonded magnet. 14. In the method for manufacturing a rare earth-transition metal-boron bonded magnet according to claim 13, the binder in the mixing step is a thermosetting resin, and after the magnetic field forming step, the molded body is heated by the heat of the thermosetting resin. 1. A method for producing a rare earth-transition metal-boron bonded magnet, comprising a molded body heat treatment step in which heat treatment is performed at a curing temperature. 15. 15. The method of manufacturing a rare earth-transition metal-boron bond magnet according to claim 14, wherein the thermosetting resin in the mixing step is an epoxy resin. 16. The method of manufacturing a rare earth-transition metal-boron bond magnet according to claim 1, wherein the binder in the mixing step is a thermoplastic resin. 17. 17. The method of manufacturing a rare earth-transition metal-boron bond magnet according to claim 16, wherein the thermoplastic resin in the mixing step is polyethylene. 18. In the method for manufacturing a rare earth-transition metal-boron bonded magnet according to claim 16, in the magnetic field molding step, the mixture is heated at the melting temperature of the thermoplastic resin in an orienting magnetic field, and then molded into a mold. A method for producing a rare earth-transition metal-boron bonded magnet, which comprises producing a molded body by injection. 19. In the method for manufacturing a rare earth-transition metal-boron bonded magnet according to claim 1, the quenching step includes jetting the molten alloy onto the outer peripheral cooling surface of a cooling roll member rotating at a predetermined speed. A method for producing a rare earth-transition metal-boron bonded magnet, which comprises rapidly cooling the ejected molten alloy to produce the R-T-B ribbon or flake. 20. The method for manufacturing a rare earth-transition metal-boron bond magnet according to claim 19, wherein the quenching step includes applying a magnetic field in the radial direction of the quench roll member to quench the ejected molten alloy. A method for producing a rare earth-transition metal-boron bonded magnet. 21. In the method for manufacturing a rare earth-transition metal-boron bonded magnet according to claim 19, the quenching step includes providing a plurality of protrusions on the outer peripheral cooling surface of the cooling roll member.
And, a cooling plate member is arranged adjacent to the cooling roll member, and the cooling plate member is arranged adjacent to the cooling roll member, and the molten alloy lost to the outer circumferential cooling surface of the cooling roll member is removed. A method for producing a rare earth-transition metal-boron bond magnet, which comprises producing the R-T-B flakes. 22. In the method of manufacturing a rare earth-transition metal-boron bonded magnet according to claim 21, the quenching step reduces the thickness of the flat R-T-B flakes to substantially 7 to 500 μm.
A method for producing a rare earth-transition metal-boron bonded magnet, characterized in that the magnet is made of m. 23. In the method for manufacturing a rare earth-transition metal-boron bonded magnet according to claim 1, in the quenching step, the cooling roll member has first and second cooling roll parts, and the molten alloy is transferred to the first The spouted molten alloy is spouted onto the outer circumferential cooling surface of the roll portion, and the spouted molten alloy is rapidly cooled to form the first R-T-
A method for producing a rare earth-transition metal-boron bonded magnet, which comprises producing the first R-T-B alloy ribbon after producing the B alloy ribbon. 24. In the method for manufacturing a rare earth-transition metal-boron bonded magnet according to claim 1, the quenching step includes spraying the molten alloy from a spray nozzle to powder, and rapidly cooling the molten alloy on a cooling plate surface. - A method for producing a rare earth-transition metal-boron bonded magnet, characterized by producing T-B flakes.