JPS6148904A - Manufacture of permanent magnet - Google Patents

Abstract

PURPOSE:To produce a thin shaped magnet with good yield by a method wherein rare earth-Fe-B system alloy is refined and powdered, that is, fine grinding is performed after rough grinding, the material is subjected to compression forming in magnetic field and hot extruction process is performed after canning. CONSTITUTION:An ingot, which is the refined alloy of composition showed by the formula, is subjected to rough grinding by stamping mill and jet mill, then is subjected to fine grinding by jet mill. Thereafter, the said powder is subjected to compression forming in magnet field and canning is performed to a forming body using a can made by iron. In this formula, R means Nd only or combination of Nd and one or more than 2 of the othe rare earth element, and M means combination of one or more than 2 of Al, V, P, W, Ti, Ni, Nb, Cr, Mo, Si, Zr, Hf, Mn, Bi, and Sn and Sb. 0<=X<=0.5, 0.02<=Y<=0.3, 0<=Z<=0.03, 4<=A<=7.5. Consequently, hot extrusion process is performed at within the temperature of 600- 1,150 deg.C and extrusion ratio of 3-20. Thus, a thin shaped magnet can be produced with good yield.

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention is directed to rare earth gold ff1 (hereinafter abbreviated as R) and Fe
The present invention relates to a method for producing an all-living compound permanent magnet consisting of: Basically R-Fe containing B as its constituent element
-8 This relates to a method for manufacturing an intermetallic compound magnet. In particular, it relates to a method for manufacturing thin-walled arc-shaped magnets, which are difficult to manufacture by powder metallurgy.

"Prior Art" R-Fe-B permanent magnet materials are being developed as a new composition system that can provide higher magnetic properties than R-Co permanent magnet materials. (JP-A-59-460O8, JP-A-5'9-64733.

JP-A-59-89401, M, SaOawa
etal JAP55 ('6) 2083 (1984
) “New Materials for pe'
rmanent ma'gnetson a base
According to these, for example, Nd+r, Fe75 s 10 [atomic% 1
N d (F eO,9flB0.12 >5.7
] (B)-1) n1ax ~35MGOe
.

Magnetic properties of IHC ~ 10KOe are obtained, and by replacing a part of Fe with Co, the Curie point is improved.Surco, Ti, Ni, Bi, V, NFJ,
Ta.

Cr, MO,'W, Mn, Al, Sb, Ge, Sn.

It has been shown that the addition of Zr and Hr improves IHC.

(B H) ma obtained with these R-Fe-B alloys
x reaches 35 ~ l G Oe, and 1 with R-Go magnets.
(BH) max~30MGOe, which is qqd. These permanent magnet materials are produced by powder metallurgy. That is, it is manufactured through the steps of ingot preparation by vacuum melting, crushing, molding in a magnetic field, sintering, heat treatment, and processing. The melting is carried out in a conventional manner in A1 medium or in vacuum. Ferroboron can also be used as B, and the rare earth element is added last. Grinding can be divided into coarse grinding and fine grinding, and coarse grinding involves stamp mills,
Show crusher, brown mill, disc mill,
Further, fine pulverization is performed using a jet mill, a vibration mill, a ball mill, or the like. Both processes are carried out in a non-oxidizing atmosphere to prevent oxidation, but long-term dissolution and inert gas are used.

The pulverized particle size is 3 to 5 μm' (F 1scher sub
−5ievesizer> is desirable. Molding is performed in a magnetic field by molding. This is a necessary technique to impart anisotropy, and in the case of this alloy, it is an essential step to align the crushed powder with C@. However, there are limits to the compacted powder that can be obtained by molding, and it has generally been difficult to manufacture thin, arc-shaped products. This is because when the powder is oriented and molded simultaneously in a magnetic field, non-uniform density occurs in the compact, making it impossible to obtain a compact with sufficient strength and without chips or cracks. Therefore, in the case of a thin-walled product, it is manufactured by cutting and cutting a thick-walled molded body after sintering. Sintering is carried out in an inert gas such as Ar, He, etc. or in a vacuum at a temperature in the range of 1050 to 1150°C. Furthermore, sintering in H2 gas is also possible. Heat treatment varies depending on the rare earth element and composition used, but
It is carried out at a temperature range of ~1000°C. Processing is cutting.

Various methods such as surface grinding, internal grinding, centerless grinding, and double-sided grinding are used, but in the case of thin-walled products, the processing range is large and the cost is high in terms of yield per man-hour.

"Problems to be Solved by the Invention" As mentioned above, the thickness of arc-shaped magnets obtained by the conventional techniques of powder metallurgy and sintering is limited to 3+ nm, although it depends on the area of one arc of the arc. For example, in Figure 1 (a
) In the case of the arc-shaped magnet shown in (b),
A rectangular f2 magnet of approximately 2 mm x 18 mm x 6.5 mm is manufactured and processed, and it is manufactured by manufacturing and processing an arc with a thickness of approximately 5 mm. Therefore, the product yield was greatly reduced due to processing. Furthermore, even when a thick arc-shaped magnet is produced in advance, cracks and cracks occur frequently during molding, which significantly reduces the yield. Therefore, the production rate of thin-walled arc-shaped magnets is extremely high due to poor yield, which limits the field of application and prevents the development of a wide range of applications.

"Means for solving the problem" and "effect" In order to solve the above problems, extrusion processing is used in the present invention. Extrusion processing is carried out at a temperature of 600 to 1150'C, and requires die design that takes the product shape into consideration, but it yields a dense extruded material that is very similar to the final product.Extrusion processing is performed by forming in a magnetic field. This method does not require sintering, as the densification of the compact is achieved during heating or extrusion of the canned billet.The extruded material is long in the extrusion direction. A rod-shaped product is obtained, and the canning material that is present on the surface of the extruded material due to processing is removed.

Cutting is done and the desired product is obtained.

In extrusion processing, pressure is applied during extrusion, so products with excellent mechanical strength can be continuously produced even if they are thin-walled.

FIG. 2 shows a comparison of manufacturing steps in the conventional method and the method according to the present invention.

The alloy that is effective using the manufacturing method according to the present invention is R(F
e, -x-n, Cox BXM, )A (here, R is Nd alone or a combination of one or more rare earth elements centered on Nd and Pr, M is AI, V, P,
'vV, Ti, Ni, Nb, Cr.

Mo, Si, Zr, 1-1f, Mn, Bi, Sn.

One type or combination of two or more types of sb, 0≦X≦0.5
．． 0.02≦y≦0.3. O≦z≦0.03,4
≦A≦7.5). Basically, it utilizes the mechanical properties of R2Fe and 4B alloy. Here, the reason for limiting the alloy composition will be described.

When the substitution fix of Co exceeds 0.5, 4πlr decreases significantly, which is not preferable as a permanent magnet material. If the CO equipment does not exceed 1?1tJiX S 0.5, you can take advantage of the improvement of one cucumber. If B substitution my is less than 0.02, the Curie point will not increase and high ZHC will not be obtained. On the other hand, when y exceeds 0.3, the Curie point (4π)r decreases, and a phase with unfavorable magnetic properties appears. M element does not need to be contained, but M
Coercive force increases due to the inclusion of elements, and when 2 is 0.0001 or more, an improvement in zHc can be expected. On the other hand, when X exceeds 0.03, 4πIr(Br) and squareness decrease,
Not preferred as a permanent magnet material. If A is less than 4,
When 4πlr decreases and exceeds 7.5, a phase rich in Fe and Co appears, and the decrease in x l-lc becomes remarkable.

If the hot extrusion temperature is 600° C. or lower, the plastic deformation is insufficient and extrusion is impossible, and if the hot extrusion temperature is 1150° C. or higher, the inevitable liquid phase inhibits hot extrusion processing. When the extrusion ratio is less than 3, the orientation is changed by extrusion i, s! If the density cannot be achieved and exceeds 20, processing by normal extrusion becomes impossible.

"Example"<Example1> Nd (Feo,, Coo, lQ BO, O'l?
An alloy of S'0.02)S,'; was produced by high-frequency melting. The obtained ingot was coarsely pulverized using a stamp mill and a jet mill, and after adjusting to 32 mesh or less,
Finely ground with a jet mill. N2 gas was used as the grinding medium to obtain a fine powder with a particle size of 3.5 μm (FSSS). Rubber press this finely pulverized powder to ~60mmφ x ~1
A molded body of 00 mmt was produced. The orientation direction is the radial direction. The rubber press was performed according to the following procedure. Inner diameter 40mm
5 in a relatively hard rubber tube of φ x height 120mmt.
Finely pulverized powder was filled and stacked while applying a KOe magnetic field.

After fixing both ends, pulse orientation of 30 KOe was further performed, and molding was performed using a hydrostatic press at a pressure of 6°C on/am2. The molded body was canned using a can made of pure iron. The thickness of the can is 5 mm. After canning, a vacuum was drawn to remove the gas inside the can. The canned molded body was heated to 1050° C. for 30 minutes and extruded. The processed flat plate had a thickness of 4 mm and a width of 30 ml. Note that the anisotropy direction of the billet was adjusted in advance so that it was parallel to the thickness direction of the flat plate. The extrusion ratio is 10
．． 5 and the extrusion pressure was 85/cn+'. After cutting the obtained flat plate into a length of 40 mm, Fe was removed by hand polishing in the thickness direction.

By the above processing, 40mm x 30mm x 3mm
A magnet with the shape of was obtained. Roughly, the remaining F in the 30mm direction
e is removed by grinding and finally 4ox 28x 3
(1 m) flat magnet was obtained. The obtained flat magnet is 6
The sample was heat-treated at 00'C for 1 hour and quenched in Si oil. The magnetic properties of this flat magnet were as follows.

Br-12500G sHc ~ 1?000Q6 IHc ~13500Q6 (B H) max ~37.2M G Oe density ~7
．． 42 g/cc For comparison, rubber press sintering (1100
℃×2hr in Ar), heat treatment (600”CX lhr(
A flat magnet with a diameter of 1 mm) was produced.

The obtained magnetic properties are: Br ~11800G aHc ~92000e THc ~103000e (BH) max ~32.5M GOe density ~7,
It was 361J/'CO. It was found that the magnetic properties obtained by extrusion processing were significantly improved. The improvement in 3r is due to the improvement in the degree of orientation obtained during extrusion, and the improvement in IHc is due to grain refinement.

Therefore, the degree of orientation is high due to hot extrusion processing.

It can be seen that a thin plate magnet with high r l-1c can be obtained.

<Example 2>"" (Fe111128O, Q9 T'LOD@)
5.0 was melted in the same manner as in Example 1.
It was crushed and finely pulverized. Furthermore, in the same manner as in Example 1, a 35 mmφ×100 mmt molded body was produced using a rubber press. The orientation direction is the radial direction. With the goal of producing the arc-shaped magnet shown in Figure 1, the outer diameter was 11 mm.
．． 4mm.

107 with an inner diameter of 8.4n+m and a 7-angle of 130°.
Hot extrusion processing was performed at 0°C. The billet anisotropy direction and the arc thickness direction were parallel. The extrusion ratio was 16 and the extrusion pressure was 10tOn/Cm2. Grinding was performed in the same manner as in Example 1, resulting in the arc shape shown in Figure 1! ! I got a stone. After the grinding process, heat treatment was performed at 650° C. for 1 hr in Ar, followed by quenching in Si oil.

The obtained kidney characteristics are as follows: Br ~12800G BHc~112000° rHc~14000o.

(BH) maX +-38,7M G Oe density ~7
．． 43 (1/'cc).

For comparison, a sintered body with a thickness of 5t was created by vertical magnetic field forming,
Heat treatment was performed. Sintering conditions are 1080℃ x 2hrsA
heat treatment at 650°C x 1 hr (heat treatment iD in Ar)
A magnet having the shape shown in FIG. 1 was produced by further processing (quenching in Si oil).

The obtained magnetic properties are: Br-11200G a Hc ~100000e IHc ~1160008 (B H)max ~28,9M Gos density ~7
, 33 g/CO It can be seen that the arc-shaped magnet obtained by extrusion has a higher degree of orientation than that obtained by the conventional method of field forming synthesis.

<Example 3> (N d,, D y,, 1.) (F eo, 92
B,,,, )5. An alloy consisting of , was melted, coarsely pulverized, finely pulverized, and rubber pressed in the same manner as in <Example 1>. The orientation direction is the height direction, and the molded product formed by rubber press has a size of 45 mmφ×10 −0 m m t. (Fe
The thickness of the can is 2.5 mm.

) With the goal of obtaining a magnet with an inner diameter of 10 mmφ, an outer diameter of 20 mmφ, and a height of 3 mm, the inner diameter is 9. '5mmφ, outer diameter 20.5mm
A cylindrical extruded material with a diameter of φ was produced. The extrusion ratio is 7.6. The extrusion pressure was 7 ton/cm'', and the extrusion temperature was 1050°C.The Fe sleeve was removed by internal and external grinding and cut into pieces with a height of 3 mm.After processing, heat treatment was performed at 670°C in XIhrAr to improve magnetic properties. It was measured.

The obtained magnetic properties are: Br ~ 11200G aHc ~ 110000e I Hc ~ 258000G (B H) max ~ 31. The OMG Os density was ~7.45 g/cc. For comparison, the same shape was fabricated by vertical magnetic field molding. The magnetic field strength during magnetic field forming was 8K Oe,
The molding pressure was 3tOn/C1n2. Sintering G: Sintering was carried out at 1120'Cx for 2 hours in tAr and cooled in a furnace. Heat treatment is 6
It was carried out at 70° C. in IHrAr and cooled in Si oil for 8 hours.

The obtained magnetic properties are as follows: Br-10400G BHc ~98000c rHc ~175000e (B H) max ~25 ~ I G Oe density ~7.
It was 40g/cc. The toroidal magnet obtained by extrusion has a higher degree of orientation than the conventional method using vertical magnetic field forming.
c is reduced to 19. Figure 3 shows the billet (
The anisotropic direction (arrow M) of the extruded material (right figure) and the extruded material (left figure) are shown together. Figure 3 (a) shows the flat magnet of Example 1, (b) shows the arc-shaped magnet of Example 2, and (C) shows the example 3.
The case of a toroidal magnet is shown.

"Effects of the Invention" As shown in the examples above, by using the extrusion method according to the present invention, thin-walled magnets can be produced with a high yield, and due to the high degree of orientation and fine crystal grains, high 3r, high zHc, and high (B
H) Maximum R-Fe-B permanent magnet material can be obtained.

[Brief explanation of the drawing]

Figure 1 is an example of an arc-shaped magnet, Figure 2 is a comparison of the manufacturing process of the conventional method (powder metallurgy) and the method according to the present invention (extrusion method), and Figure 3 is the anisotropy of billet and extruded material in each example. It shows the direction of sexual orientation. Fig. 2 Follow-up method (powder metallurgy) (powder metallurgy) (Powder metallurgy) Fig. 3

Claims (1)

[Claims] R(Fe_1_-_x_-_y_-_zCo_xB_y
M_z)_A (Here, R is Nd alone or Nd and Pr
One or a combination of two or more rare earth elements centered on, M is Al, V, P, W, Ti, Ni, Nb, Cr,
1 of Mo, Si, Zr, Hf, Mn, Bi, Sn, Sb
species or combination of two or more species, 0≦x≦0.5, 0.0
2≦y≦0.3, 0≦z≦0.03, 4≦A≦7.5)
An alloy having a composition of
A method for producing a permanent magnet, characterized by hot extrusion processing.