JPS62173704A - Manufacture of permanent magnet - Google Patents

Abstract

PURPOSE:To remove the formation of a nonmagnetic phase unnecessary for a permanent magnet, and to obtain a sufficient lubrication effect by using the impalpable powder of a B1-mFem(0<=m<=0.6) alloy as a lubricant. CONSTITUTION:An alloy having the composition of R(Fe1-x-y-zCoxByMz)A is dissolved and pulverized, and boron B is diffused and reacted, thus acquiring a permanent magnet employing a compound having a tetragonal system crystal structure as a main phase. Where R represents single Nd or one kind or combi nation of two kinds or more of rare earth elements centering Nd and Pr, M represents one kind or combination of two kinds or more of Al, U, P, W, Ti, Ni, Nb, Cr, Mo, Si, and 0<=x<=0.55, 0<=y<=0.02, 0<=z<=0.04, 3<=A<=7.5 hold. The finely-ground powder and pulverized B1-mFem (0<=m<=0.6) alloy are mixed at that time, and molded in a magnetic field, and B is reacted and diffused and the whole is baked. Accordingly, the formation of a nonmagnetic phase is re moved, and a sufficient lubrication effect is acquired.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a method for producing permanent intermetallic compound (Zhuangseki alloy) mainly composed of Nd and 1, especially Nd-Fe-B permanent magnets. be.

(Prior art) R-Fe-B permanent magnet materials are being developed as a new composition system that can obtain higher magnetic properties than R-Co permanent magnet materials. , JP-A-59-64733, JP-A-59-89401
Publication, M, Sagawa et al J, A, P,
55 (6) 2083 (1984) New Ma
terials for 'Permanent
magnets on a base of nda
According to Kore et al., for example, Nd+5F
When expressed as etJs (atomic %), that is, the mole fraction ratio, Nd(Fo, , +Bo, +19) S, ? (B H) IIIax ~35MGOe.

Magnetic properties of 111c to 10KOe can be obtained, and by replacing a part of Fe with Co, the Kugu point can be improved by one point, Ti, Ni, Bi, V, Nb+Ta, Cr, M
o, W, Mn, Al tSb.

It has been shown that addition of Ge, Sn, Zr, t(f, etc.) improves iHc.

The (BH) wax obtained with these R-Fe-B alloys is 3
It reaches as much as 5MGOe, which is obtained with R-Co magnets (
BH) wax ~30 Much higher than MGOe.

These permanent magnet materials are manufactured 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 or in a vacuum. Ferroboron can also be used as B, and the rare earth element is added last. Grinding is divided into coarse grinding and fine grinding. Coarse grinding is carried out using a stamp mill, Shaw crusher, Brown mill, or disc mill, and fine grinding is carried out using a die-nod mill, vibration mill, ball mill, etc. Both are carried out in a non-oxidizing atmosphere to prevent oxidation, but organic solvents and inert gases are also used.

Note that the molding is performed in a magnetic field by molding.

This is done to impart anisotropy, and in the case of this alloy, it is an essential step to align the C-axes of the pulverized powder.

[Problem that the invention seeks to solve]

As mentioned above, the R-Fe-B permanent magnets are conventionally manufactured by powder metallurgy, and the alloy raw material is molded using a mold.

However, the R-Fe-B permanent magnet alloy fine powder has a drawback of poor formability. In other words, the present alloy fine powder has a low pressure transmission rate during molding, which may be less than 50%, for example. To avoid this phenomenon, stearate-based metal soaps and waxes such as calcium stearate, magnesium stearate, and aluminum stearate are generally added as lubricants. However, the addition of lubricant is B
Deterioration of magnetic properties such as r and +IIc+ (Bll)ma was unavoidable. Furthermore, these lubricants tended to separate from the magnetic powder during compaction in a magnetic field, and were the cause of cavities in the sintered body.

[Means and effects for solving the problems] In order to solve the above problems, the present invention does not sinter a compact of alloy powder for magnets, but sinters a mixture of master alloy powder and boron in a magnetic field. The process involves molding the material and then firing it by reaction.

That is, R(Fe+-x-y-scOxB, MJA (here, R is NdjXL or a combination of one or more rare earth elements centered on Nd and Pr; M is Ae
, v, P, W, Ti+Ni+Nb, Cr, Mo, Si
+One or a combination of two or more of Zr, llf, Mn, old, Sn, and Sb; 0≦x≦0.55; 0≦y≦0.
02; 0≦z≦0.04; 3≦A≦7.5) After melting and pulverizing an alloy, the alloy has a substantially tetragonal crystal structure by causing B (boron) to undergo a diffusion reaction. R (Fe+-x-y-zcOx8yMJ
A (here, R is Nd alone or a combination of one or more rare earth elements centered on Nd and Pr; M is ^1
, V, P, W, Ti, Ni, Nb, Cr, Mo, Si
, Zr, Hf, Mn, Bi, Sn.

One type or combination of two or more types of Sb; 0≦x≦0.55
;0.02≦y≦0.3;O≦z≦0.03;4≦
In the method for manufacturing a permanent magnet having a composition of A≦7.5), the finely pulverized powder is mixed with a finely pulverized Bl-MPes (0 part m≦0.6) alloy, molded in a magnetic field, and B reaction diffusion firing. It is characterized by carrying out the following. That is, in the present invention, a fine powder of an a+-mpem (o≦m≦0.6) alloy is used as a lubricant. Therefore, Bt-Je, which is a constituent element of this magnetic alloy, can be used without using stearic acid-based metal soap or wax.
Since R (0 part m≦0.6) is used, there is no generation of non-magnetic phase unnecessary for the permanent magnet, and a sufficient lubricating effect can be obtained.

The present invention will be explained in more detail below.

In the present invention, R(Fe+-x-y-gcoxBy
M2) A product having the composition A is melted and then cast and pulverized.

Specific elements of R and M of the master alloy powder and x, y, z
The range of is as described above, and among these, the type or combination of RIM, R, Fe, Co.

The content of M is determined by the composition of the magnet to be obtained and the composition of the BI-, Fe, (0 part m≦0.6) alloy used as the lubricant. Therefore, the required amount and composition of the lubricant are determined by the shape and size of the magnet, and this determines the composition of the fine powder that is to become the magnet matrix.

On the other hand, B+-aFelI (0 parts m≦0.6) is melted and cast.

When m=o, crystal boron is used, and if the composition is appropriate, commercially available ferroboron can also be used as the B--Fe alloy. R(pel-X-V-gCOX
ByMz) A master alloy and B,'-,Fe, alloy are each pulverized by a jet mill or the like. Both fine powders are weighed and mixed so as to have a target composition and to obtain a sufficient lubricating effect, and then compression molded in a magnetic field. B, -, Fe.

By using alloy powder, there is no galling phenomenon between the goo wall and the compact, and a pressure transmission rate of 85% can be easily achieved. The obtained molded body is heated in a vacuum at a temperature around 1 to 4 hrsllOO℃,
It is fired in an Ar atmosphere. Firing temperature and time are at-m
Fem (0 part m≦0.6) varies depending on the composition of the alloy.

The obtained fired body was heated to 900°C for 2 hours and heated to 1.5°C.
Cool to room temperature at a cooling rate of /min. Another 550
Aging for lhr at ~680°C and quenching in water.

R' (Fe amount-x-y-zcO
xByMz) A (here, R is Nd alone or Nd and P
One or a combination of two or more rare earth elements centered on r; M is Al, V, P, W, Ti, Ni, Nb
, Cr, Mo, Si, Zr+ Ilf, Mn, B
i, Sn.

One type or combination of two or more types of Sb; 0≦x≦0.55
;0≦y≦0.02;O≦z≦0.04;3≦A≦7.
5) Bil of the master alloy was 0.02 or less. This is 0.
If B exceeding 02 is contained, it becomes necessary as a lubricant,
, Fe, and alloys cannot be added. Also s, -1l
The amount of Fe in the pen (0 part m≦0.6) alloy was 0.6 or less. This is because a lubricating effect cannot be obtained when Fe equal to 0.6 is contained. Also, A 12 , V, P, JTi, Ni+Nb, C in a part of B+-, Fe, 1 alloy.
r, Mo, Si, Zr, Hf, Mn.

It is also possible to add trace amounts of Br + Sn and Sb.

The reasons for limiting the alloy composition in the permanent magnet of the present invention will be explained below.

X: 4π if CO substitution ff1x exceeds 0.55
The decrease in Ir is large, making it undesirable as a permanent magnet material. If X is less than 0.55, you can take advantage of a one point improvement.

If the y:B substitution amount y is less than 0.02, the Curie point will not increase and high iHc will not be obtained.

On the other hand, if y exceeds 0.3, one cuuri point,
4πrr decreases, and a phase with unfavorable magnetic properties appears.

z: The M element does not need to be contained, but the coercive force increases by containing the M element, and when 2 is o, oooi or more, an improvement in 111c can be expected.

On the other hand, if 2 exceeds 0.03, 4πIr(Br)
and the squareness is decreased, making it undesirable as a permanent magnet material. When A is less than 4, 4πlr decreases, and when it exceeds 7.5, a phase rich in Fe and Co appears, and the decrease in 1llc becomes significant.

The present invention will be explained below with reference to Examples.

Example l NdFe4. An alloy called s is created by arc melting,
It was coarsely ground with a disc mill and adjusted to 32 mesh or less. The adjusted coarse powder is finely pulverized with a jet mill to give 3.5
A finely ground powder of μm (FSSS) was obtained. N2 gas was used as the pressure medium of the jet mill. On the other hand, commercially available crystal boron is coarsely pulverized using a disk mill to give I.
I did it. Furthermore, using a jet mill, 2.17 m (
A finely ground powder of FSSS) was obtained. NdFe4.5 and B
i Mix the crushed powder and Nd(Feo, q Bo, +)
Adjustments were made to achieve a target composition of s. The obtained prepared molding was subjected to transverse magnetic field molding. The magnetic field strength was 15 KOe, and the sample shape was 15×15×15 (am). Molding pressure is 4 to
n/cnl. Continuous molding was possible, and the pressure transmission rate was 85%. This molded body was heated to 1100”C in vacuum.
It was fired for 3 hours. After firing, the sample was cooled to room temperature in a furnace, heated again at 900° C. for 2 hrs, and continuously cooled at a cooling rate of 1° C./min. After cooling to room temperature, aging treatment was performed at 620°C.

The obtained magnetic properties are Br-9950G , Hc ~72500e ,tic~81000e (811)max~22.8 MGOe.

(Example 2) A master alloy of Nd(Feo, qaBo, Of) 5.2 was melted, coarsely pulverized and finely pulverized in the same manner as in Example 1.

This alloy was mixed with finely crushed crystal boron in the same manner as in Example 1, and Nd (Feo, qzBo, o
ll)3. , was obtained as the target composition. This refined powder was molded in a transverse magnetic field in the same manner as in Example 1. Continuous molding was also possible with this adjusted powder, and the pressure transmission rate was 80%. The obtained molded body was fired and heat treated in the same manner as in Example 1.

The obtained magnetic properties are Br-12300G ,,llc~81000e , 110-85000e (Bll)max~36. It was InGOe.

Example 3 Nd. , xDyo, z <Feo, q l 2C
OQ, obaBo, 02) 4. ll and B,
. Fes. The alloys were respectively melted, coarsely pulverized, and finely pulverized in the same manner as in Example 1. Both alloys and target composition Nd0,
eDyo, z (Feo, l16CO0,06BO
, os) s, s. This adjusted powder was subjected to transverse magnetic field molding in the same manner as in Example 1, but continuous molding was possible and the pressure transmission rate was 78%. Note that the molding pressure was 2 ton/cx1. The obtained molded body was used in Example 1.
It was fired and heat treated in the same manner. However, the aging temperature was set at 1 to 600°C.

The obtained magnetic properties are Br-10600G , 1(c~102000e +IIc~2 3 0 0 00e (Bit)max~26.9 MGOe.

(Example 4) The master alloy shown in Table 1 was melted, coarsely ground, and finely ground in the same manner as in Example 1, and mixed with the finely ground lubricant crystal boron. The target composition is also shown in Table 1. The mixed adjustment mask was molded in a transverse magnetic field, but continuous molding was possible. The obtained molded body was fired and heat treated in the same manner as in Example 1. The aging temperature was 600°C. The obtained magnetic properties are shown in Table 2.

(The following is a blank space) [Effects of the invention] As explained in the above embodiments, 8. , Fe, (0≦
m≦0.6) Continuous molding is possible by using finely pulverized powder as a lubricant, and the magnetic properties also show sufficient values as a practical material.

Do-)-

Claims (2)

[Claims] (1) R(Fe_1_-_x_-_y_-_zCo_x
B_yM_z)_A(Here, R is Nd alone or Nd
and a combination of one or more rare earth elements centered on Pr; M is Al, V, P, W, Ti, Ni, Nb, C
r, Mo, Si, Zr, Hf, Mn, Bi, Sn, Sb
One or a combination of two or more; 0≦x≦0.55; 0
≦y≦0.02; 0≦z≦0.04; 3≦A≦7.5)
After melting and finely pulverizing an alloy having the following composition, B (boron) is subjected to a diffusion reaction to produce R (Fe_1_-_x_-_y
____zCo_xB_yM_z)_A, (here R is N
d alone or one of the rare earth elements mainly Nd and Pr
species or combination of two or more species; M is Al, V, P, W, T
i, Ni, Nb, Cr, Mo, Si, Zr, Hf, Mn
, Bi, Sn, Sb or a combination of two or more; 0
≦x≦0.55; 0.02≦y≦0.3; 0≦z≦0.
03; 4≦A≦7.5), in which the finely pulverized powder and the finely pulverized B_1_-
_mFe_m (0≦m≦0.6) alloy, forming in a magnetic field, B reaction diffusion firing. (2) R(Fe_1_-_x_-_y_-_zCo_x
B_yM_z)_A(Here, R is Nd alone or Nd
and a combination of one or more rare earth elements centered on Pr; M is Al, V, P, W, Ti, Ni, Nb, C
r, Mo, Si, Zr, Hf, Mn, Bi, Sn, Sb
One or a combination of two or more; 0≦x≦0.55; 0
≦y≦0.02; 0≦z≦0.04; 3≦A≦7.5)
Alloys with the composition and B_1_−_mFe_m (0≦m
≦0.6) The method for producing a permanent magnet according to claim 1, wherein the average crushed particle size of the alloy is 0.5 to 50 μm.