JPH01247A - Permanent magnet material and its manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to R, Co, intermetallic compounds (wherein R is S
The present invention relates to an R-Co-Cu-Pe-Zr-B permanent magnet material that is mainly composed of a rare earth metal (Ll) and has excellent magnetization properties, and a method for manufacturing the same.

This type of magnet is collectively referred to as R, Co, and type, and the typical S&Tco+'r type magnet is used in electromagnetic conversion equipment (motors, etc.) that requires small size and high performance due to its high magnetic properties.
is widely used.

[Conventional technology]

5IIIzCol, type Ss-Go-Cu-Fe
-Zr-based permanent magnets are magnets whose performance has been improved by adding a small amount of Zr (Japanese Patent Publication No. 55-48094). SmzCO compared to conventional SmCo5 type magnet
+, type magnets have a large saturation magnetization and can provide high magnetic properties. However, since the Sm, Go, and 7 electromagnets generate coercive force due to the pinning of domain walls, their magnetization is not as good as that of the 5sCos type magnet, in which the coercive force is determined by the generation of reverse magnetic domains. Therefore, in cases where there is a practical limit to the magnitude of the magnetizing magnetic field, S+a
For example, when magnetizing a ring-shaped magnet with multiple poles,
Sw+Col type magnet with better magnetization is Sn+zCO+
There is a report that it gives a higher surface magnetic flux density than a type magnet (Noguchi et al., Abstracts of the 9th Japan Society of Applied Magnetics, Academic Conference, 1985, p. 35). Performance of various magnetic parts 5
In order for a llxCO+ type magnet to be superior, it is necessary to improve the magnetizability of the magnet, and there have been no reports to date showing effective means for tackling this problem.

[Problem that the invention seeks to solve]

The magnetizing magnetic field usually obtained for magnetizing various magnetic components is 20 to 25 kOe. Therefore, the magnetic properties of the magnet must be sufficiently exhibited by its magnetizing magnetic field.

SwzCO+ type magnet Ss -Co -Cu -Fe
- In the Zr system, high properties can be obtained with a low Cu (10 wt% or less) and high Fe (15 wt% or more) component system.
We found that Go-25,5 in weight percentage (ht%)
wt%Srn-6wt%Cu-(17-21)wt%
In the process of improving the performance of an anisotropic bonded magnet made of an alloy represented by Pe-2wt%Zr, we found that the magnetization was extremely poor under heat treatment conditions where the coercive force iHc and the maximum energy product (all)+++ax were maximized. I discovered something. Under the above heat treatment conditions, in addition to the fine cell structure (cell spacing ~50nw+) unique to this alloy, coarse precipitated phases (
zonal structure, hereinafter referred to as X phase, ~0.5μ
It was determined that this was due to the appearance of ``l1l''. X1
Report by ao Yaofu and ZhangZhengyi (
Proc, 8th InterJorkshop on
Rare-Earth Magnets and Th
eir Applications.

1985, P257, this X phase has an S+5CoB type crystal structure (or, according to the research of the present inventors, an Sm2CoI? type crystal structure), and contains fine particles that act as pinning sites for strong domain walls. The cell organization is 5llx inside the cell (Code) I? S of phase and cell boundaries
s (CoCu) Composed of s phase. It is well known that the phase boundary between the two phases acts as a pinning site for the domain wall, but it is thought that the X phase performs stronger pinning of the domain wall than the phase boundary. In fact, X1ao Yaofu and Zh
According to the above-mentioned literature by ang Zhen-gyi, when the X phase appears, the coercive force reaches 3.QkOe or more. Therefore, in such a case, a magnetizing magnetic field of 20 to 25 kOe cannot sufficiently bring out the characteristics of the present magnet.The purpose of the present invention is to suppress the appearance of the above-mentioned X phase, thereby improving the magnetizability. shall be.

[Means for solving problems]

The gist of the present invention is as follows.

(1) Weight percentage (wt%) of R (R is a rare earth element mainly composed of Ss): 23 to 28%, Cu: 4 to 28%
16%, Fe: 15-25%, Zr: 0.2-5%, B
: A permanent magnet material characterized by comprising o, oos ~ 0.06%, the remainder consisting of Co and inevitable impurities.

(2) In terms of weight percentage (wt%), R (R is a rare and earth element mainly composed of S11) is 23 to 28%, and Cu is 4 to 28%.
lO%, Fe 15-25%, Zr 0.2-5%, B
A method for producing a permanent magnet material, characterized in that a molten alloy consisting of o, oos ~ 0.06%, the balance being Co and unavoidable impurities, is directly continuously cast and rapidly cooled into a thin plate having a thickness of 31 mm or less.

The present invention will be explained in detail below.

Precipitation in alloys is often influenced by the addition of trace elements and is also influenced by the cooling conditions of the alloy.
The present inventors have found that the precipitation of the X phase can be suppressed by adding a small amount of B to a 5s-Co-Cu-Fe-Zr alloy and directly performing continuous casting quenching treatment on a thin plate with a thickness of 3III or less. I discovered something new. Here, since the amount of B added is very small, there is almost no decrease in saturation magnetization. Therefore, the addition of B does not impair the magnetic properties (the magnetization can be improved).

Below, the magnet alloy R-Co-Cu-Fe-Zr of the present invention
- The components of the B system will be mentioned.

In the RCo Cu Fe-Zr-B system of the present invention, R is a rare earth element mainly composed of Ss;
If Cu is less than 4 wt%, sufficient coercive force cannot be obtained, and if it exceeds 28 wt%, saturation magnetization is low. If it is less than 15-t%, a sufficiently high saturation magnetization cannot be obtained, and if it exceeds 25-t%, the coercive force is low.
In the main magnetic alloy with high Fe at u, 0.2 to 5 imt
It is necessary to add within the range of %. That is, when Zr is 0.
If it is less than 2 wt%, a sufficient coercive force cannot be obtained, and if it exceeds 5 wt%, the saturation magnetization decreases significantly. B, which is the focus of the present invention, has little effect on improving magnetization when it is less than 0.005 wt%, and saturation magnetization (that is, residual magnetization) when it exceeds 0.06 wt%.
The decrease becomes so large that it cannot be ignored.

An example of adding B to a SmzCO+ based magnet alloy is disclosed in Japanese Patent Application Laid-open No. 1989-1999.
5-115304, JP 56-44741, JP 59-10562, JP 60-23
8436 and JP-A-60-238437, both of which contain B
is added, and the dressing is not intended to improve sex as in the present invention. Further, in the above-mentioned known literature, the amount of B added is extremely large. The present invention differs from these inventions in that Sm
-Co-Cu-Fe-Zr -B-based alloy molten metal was cast using a known thin plate direct continuous casting device such as a twin roll, and water-cooled to produce a thin plate-like rapidly cooled slab having a thickness of 3 taps or less.

As a result, the added B is uniformly dispersed in the matrix, making it possible to effectively prevent the precipitation of the X phase with an extremely small amount of addition. In the case of an alloy ingot produced by a normal slow cooling method, B crystallizes (or precipitates) as a compound at grain boundaries, and has little effect on improving magnetization.

[For production]

The addition of a small amount of B makes the SmzCO+ type magnet alloy
Suppresses phase precipitation and improves magnetization.

FIG. 1 shows the demagnetization curve of Sm-Go-Cu-Fe-Zr alloy color and alloy T with 0.03 wt% B added at the maximum applied magnetic field (magnetizing magnetic field) of 24 kOe. As will be explained in detail in Examples, alloy S was insufficiently magnetized, but alloy T was almost completely magnetized. FIG. 2 shows the microstructures of alloys S and T as measured by an optical microscope. The figure shows that the addition of a small amount of B suppresses the precipitation of the X phase within the grains.

[Example] Example 1 5Lll-Co-Cu-Fe-Zr with the components shown in Table 1
Alloy T, in which 0.03 wt% of B was added to the alloy color, was produced by high frequency vacuum melting. Next, the alloy slab was remelted by high-frequency induction heating in an Ar atmosphere, and continuously cast at a roll rotation speed of 20 PPM using a twin-roll type continuous sheet casting machine equipped with two copper rolls with a diameter of 300 mm in parallel.
A thin plate directly cast material with a thickness of 1.5 m was obtained by cooling with water directly below the guide roll.

Table 1 (expressed as a weight percentage, the remainder being Go and unavoidable impurities) Optimum solution temperature for alloys S and T (S is 1
150°C and T was 1130°C), and the alloy thin plate was solution-treated at that temperature for 16 hours. After solution treatment, it was rapidly cooled and held at 850°C for 1 hour as an aging treatment, and then cooled to 400°C at 1°C/+win.Next, the alloy thin plate was coarsely ground and then finely ground in a ball mill to separate the ground particles. The particle size was adjusted to an average of 90 μm.

2.6 wt% of epoxy resin was added to this powder and kneaded, and the kneaded product was heated to 4 ton/c4 in a 16 kOe magnetic field.
It was compression molded into a test piece shape (10 x 1' OX 20 m) at a pressure of . The molded body was heat-cured, and its magnetic properties were measured using a self-recording magnetometer. Figure 1 shows the maximum applied magnetic field (magnetizing magnetic field)
The demagnetization curve at 24 kOe is shown. As is clear from the figure, the residual magnetic flux density Br of the B-added alloy T is 1.1 kG higher than that of the B-free alloy S. Table 2 shows the magnetic properties in a magnetizing magnetic field of 24 kOe in comparison with the magnetic properties measured by performing pulse magnetization at 60 kOe. 60kOe
When pulse magnetization is performed, Br and (Bll
) There is almost no difference in Illax. Alloy S has poor magnetization, and in a 24 kOeO magnetizing field, (BH)IIIax
Only 72% of the saturation value (14,3 MGOe) was obtained. On the other hand, in alloy T added with B, the saturation value of (BH) max (14,1 M
GOe) was obtained, and the magnetization property was extremely good.

Figure 2 (a) shows alloy S (B:Q%), and Figure 2 (b) shows alloy T.
(B: 0.03%) is an optical micrograph after aging treatment. In alloy S, as mentioned above, X deteriorates magnetization.
Although phases appear within the grains, they are not seen in Alloy T.

Example 2 The effect of the amount of B added on magnetizability was investigated. C.

25.5wt%55-6wt%Cu 19wt%Fe
Based on a 2wt% Zr alloy, alloys with varying amounts of B added were produced. A bonded magnet was produced in the same manner as in Example 1, and its magnetic properties were evaluated. Here, the zero aging conditions are the same as in Example 1, with the solution temperature selected as the temperature that produces the highest coercive force for each alloy composition and the solution time being 8 hours.

Figure 3 shows the magnetic properties when the magnetizing magnetic field is 24 kOe and 60 kOe, and the amount of B added is 0.015 to 0.0.
At 3 wt%, the magnetization is improved while maintaining a high (BH) so ax. Here, the addition of B reduces the coercive force.

Example 3 - Alloys with different Fe contents were melted and the effect of B addition was investigated. That is, Co-25,5wt%55-6wt
%Cu-(17-21)wt%Pa-2wt%Zr alloy and an alloy in which 0.03wt% of B was added were melted and bonded magnets were produced in the same manner as in Example 1. Here, the solution temperature was set to the temperature that produced the highest coercive force for each composition, and the solution time was set to 8 hours.

FIG. 4 shows the results of magnetic properties when the magnetizing magnetic field is 24 kOe and 60 kOe. B even if the Fe content changes
The magnetization is improved by the addition of .

Example 4 A sintered magnet was produced using an alloy having the components shown in Table 1 according to the following procedure. First, a fine alloy powder was obtained by ball milling from an alloy thin plate prepared in the same manner as in Example 1, and compression molded at a pressure of 2 ton/cd in a magnetic field of 16 kOe. ~122
Sinter for 1 hour at an optimal temperature in the range of 0″C, followed by 11
Solution treatment was carried out for 16 hours at an optimum temperature ranging from 10 to 1160°C. As an aging treatment after solution treatment, it was held at 850°C for 1 to 4 hours, and then cooled to 400°C at 1°C/+sin. The coercive force is improved by increasing the holding time at 850°C. When the residual magnetic flux density Br is shown with respect to the obtained coercive force iHc, it becomes as shown in FIG.

When Hll is 60 k Oe, it is almost completely magnetized, and there is no difference in Br depending on whether B is added or not. On the other hand, when Hm is 24 k Oe, as the coercive force increases, magnetization becomes incomplete and Br decreases. Generally, magnetizability varies depending on coercive force, so in order to more appropriately evaluate the magnetizability of magnets, it is necessary to compare Br in magnets having similar coercive forces. Hm in Figure 5
As is clear from the case of 24 k Oe, the addition of B increases Br by 1 to 1.5 kG at the same coercive force.
was obtained, and the magnetizability was significantly improved. Table 3 shows the magnetic properties of alloys S (no B added) and T (0.03% B added) under conditions where the coercive force is about 10 kOe. As is clear from the table, the B-added alloy not only has significantly improved magnetization, but also has a high (BH)s+ax due to the improvement in the squareness of the demagnetization curve due to the addition of B. The reason why the magnetization property is poor in the case of B-free alloy is as follows.
This is because an X phase as shown in FIG. 2 appears in the sintered magnet as well as in the bonded magnet. Even if the apparent coercive force is the same, if there is a pinning site of a strong domain wall such as in the X phase, the magnetization becomes significantly worse. B addition suppresses the appearance of the X phase and improves magnetization by realizing a uniform fine cell structure.

〔Effect of the invention〕

The magnetization of the SmzCO+ type magnet was significantly improved by adding a small amount of B according to the present invention. The anisotropic bonded magnet used in the examples is a ring-shaped magnet and can have anisotropy in the radial direction, so its uses have been expanding in recent years. Here, when magnetizing a ring with multiple poles in the circumferential direction, the magnitude of the magnetizing magnetic field is naturally limited, but this problem can be solved by using the magnetic alloy of the present invention with good magnetization. Ru.

It is expected that when a sintered magnet is produced using the magnet alloy of the present invention, the magnetization properties will be significantly improved, and the magnetization of actual magnetic components will become easier.

[Brief explanation of drawings]

Figure 1 shows the demagnetization curves of the Ss-Go-Cu-F4-Zr alloy and the alloy with B added thereto, and Figure 2 (
a) and (b) are metallographic micrographs showing that the precipitation of the X phase is suppressed by the addition of B, Figure 3 is a diagram showing the effect of the amount of B added on magnetizability, and Figure 4 is the addition of Fe. FIG. 5 is a diagram showing the effect of B addition in alloys with different amounts, and FIG. 5 is a diagram showing the effect of B addition in a sintered magnet. Patent applicant Nippon Steel Corporation Figure 1 Figure 2 (a) 0 0.015 0. OJ O,0458(
wt%) Figure 4/7 fQ 2/ 17
fQ 2fFe(shiVi oA)
Fe (Wi%)0 4
θ /2 /6 2θg (large Oe
)

Claims (4)

[Claims] (1) Weight percentage (wt%): R (R is a rare earth element mainly composed of Sm): 23 to 28%, Cu: 4 to 10
%, Fe: 15-25%, Zr: 0.2-5%, B: 0
．． 0.005 to 0.06%, the remainder being Co and inevitable impurities. (2) The permanent magnet material according to claim 1, wherein B: 0.015 to 0.03%. (3) In terms of weight percentage (wt%), R (R is a rare earth element mainly composed of Sm) is 23 to 28%, and Cu is 4 to 10%.
%, Fe 15-25%, Zr 0.2-5%, B 0
．． 1. A method for producing a permanent magnet material, comprising directly continuous casting and quenching of a molten alloy consisting of 0.005% to 0.06%, the balance being Co and unavoidable impurities, into a thin plate having a thickness of 3 mm or less. (4) The method for producing a permanent magnet material according to claim 3, characterized in that B is 0.015 to 0.03%.