JPS6115936A - Rare earth element-base permanent magnet - Google Patents

Abstract

PURPOSE:To obtain a rare earth element-base permanent magnet having high coercive force and superior workability by very rapidly cooling a molten Cu-Ni- Co alloy contg. a rare earth element. CONSTITUTION:A Cu-Ni-Co alloy contg. a rare earth element and having a composition represented by formula I (where R is at least one kind of rare earth element such as Y, La, Ce, Pr, Nd, Pm or Sm, a=40-60wt%, b=15-35wt%, and x=5-40wt%) is refined. The molten alloy is very rapidly cooled at >=10<3> deg.C/ sec cooling rate by feeding to a cooling body rotating at a high speed such as a rotating body or a roll to form a thin plate of 30-300mum thickness. The thin plate is annealed at 500-750 deg.C to manufacture a thin plate of a rare earth element-base permanent magnet having high coercive force and superior workability.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to rare earth transition metal permanent magnets suitable for use in various electrical measuring instruments, communication devices, etc. This is due to the improvement in wax characteristics.

(Prior Art) In recent years, there has been an increasing demand for smaller size, lighter weight, higher performance, and higher reliability for various electrical measuring instruments, communication devices, and even micro motors. Therefore, as a permanent magnet used in the above-mentioned equipment, (BH)m
Materials with larger a and x are required.

By the way, there are rare earth permanent magnets that are suitable for use in the above-mentioned applications, and these magnets have been developed as high coercive force magnets since the beginning of their development, and have become commonplace.

(Problems to be Solved by the Invention) The first object of the present invention is to propose a rare earth permanent magnet that has even more excellent magnetic properties.

Although this rare earth permanent magnet has excellent magnetic properties as described above, it still has problems in that it has extremely poor workability and is difficult to magnetize after being incorporated into equipment. Therefore, such magnets had to be manufactured by, for example, the powder compaction-sintering method as shown in the manufacturing process shown in Figure 2, but in addition to requiring expensive raw materials such as rare earth elements, such a process was complicated. Another problem was that the production costs were high because several steps were required.

A second object of the present invention is to advantageously solve the above-mentioned problems and to propose a rare earth permanent magnet that is highly workable and can be produced at low cost through a simple manufacturing process.

(Means for Solving the Problems) This invention is based on new knowledge discovered through thorough research on the component composition of rare earth magnets, as well as the recently developed so-called liquid that produces thin strips directly from molten liquid. This is based on the suitable use of the rapid cooling direct plate manufacturing method. "That is, this invention has the chemical formula (Cua"'bC0100-a-b)IQQ
-X RX However, R: Y, la, Ce, Pr, Nd,
At least one selected from Pal and Sm, a:
The rare earth permanent magnet has a composition as follows: 40 to 60 wt%, b: 15 to 35 wt%, and X: 5 to aowt%.

The magnet of this invention is obtained by continuously supplying the molten metal adjusted to the above-mentioned appropriate composition onto a cooling body whose cooling surface is updated and moving at high speed, and rapidly solidifying it into a thin ribbon. This is particularly advantageous in that it allows the production of thin products with excellent workability.

(Function) The reason why the component composition is limited as described above in this invention will be explained below.

CIJ is a useful element in terms of stabilizing two-phase separation, but
If it is less than 40 wt%, a sufficient nonmagnetic phase cannot be obtained in two-phase separation1, whereas if it exceeds eowt%, saturation magnetization and eventually residual magnetization will decrease, making it impossible to ensure sufficient (B H) wax, so the content The amount was limited to a range of 40-60 wt%.

Ni is added to stabilize two-phase separation and improve magnetism, but if it is less than 15 wt%, the amount of non-magnetic phase is not sufficient, while if it exceeds 35 wt%, it takes a long time for two-phase separation. Since it also increases the cost, the content is limited to a range of 15 to 35 wt%.

CO is essential for the permanent magnet of this invention as a ferromagnetic component, and together with the above-mentioned Cu and Ni, CO is 100*
It is contained within a range of t%.

Also, Y, La, Ce, Pr, Nd, PmJ5J: (fS
All of these rare earth elements are essential elements for improving magnets, but if the content of these rare earth elements is less than 5 wt%, the effect of improving coercive force is poor, while on the other hand, even if they are added in excess of 40 wt%, Since the effect reaches saturation and is also uneconomical, it is limited to a range of 5 to 40 wt%.

Next, the manufacturing process of this invention magnet will be explained.

Although such alloy magnets can of course be manufactured by the powder compaction-sintering method as shown in Figure 2 above, it is preferable to manufacture them by the so-called liquid quenching direct sheet manufacturing method described below in terms of improved workability. Especially advantageous.

Now, the molten metal adjusted to a suitable composition is first shown in Figure 3 a and b.
A ribbon having a thickness of about 30 to 300 μm is obtained by the ribbon forming method shown in , c, d, and e. At this time, if the cooling rate is less than 103℃//S, the columnar crystal structure of the ribbon immediately after quenching will be destroyed, and it will be difficult to recover the magnetic properties even with the heat treatment described below.
It is desirable to carry out the cooling at a cooling rate of S or higher.

Since it is difficult to obtain sufficiently satisfactory magnetic properties of the thus obtained ribbon immediately after solidification, it is subsequently subjected to heat treatment.

Figure 1 shows (Cu50N'24CO!6)80Nd produced by the twin roll method shown in Figure 3C above.
The results of investigating the coercive force iHc when a 150 μm thick ribbon having a composition of 2° was heat treated in argon gas (retained for 1 hour) are shown in relation to the heat treatment temperature.

As is clear from the figure, excellent coercive force can be obtained by annealing at a temperature of 500 to 750°C.

In addition, such a rapidly solidified ribbon is flexible and has excellent toughness, and
Even if it is bent 80 degrees, it will not break immediately (therefore, it has excellent workability.

In manufacturing such a permanent magnet ribbon, the process shown in Figure 4 is sufficient, and therefore, compared to the conventional process shown in Maego Figure 2, it is advantageous in process saving and cost reduction. It will be achieved.

(Example) Example 1 (Cus+s N +25 COso )so N
An ingot of 10 kg was produced from an alloy having a component of dgo, and then ground into a fine powder of several μm in size using a crusher. This fine powder was then compression molded at a pressure of about 5 tons/d. At this time, an applied magnetic field of about 5 kOe was applied. The material thus obtained was sintered at 1150°C, slowly cooled to 800°C, and immediately rapidly cooled from 800°C.

The magnetism at this time is shown in Table 1.

Example 2 A molten metal having a composition of (Cu2.N1□5CO5o)8oNd2o was rapidly solidified by a twin roll method at a cooling rate of 103° C./S to form a ribbon with a thickness of 200 μm.

Table 2 shows the change in holding force iHc over time when this ribbon was annealed for 5 hours in an Ar atmosphere. .

Example 3 Five types of molten metals having the component compositions shown in Table 3 were rapidly solidified by a twin roll method at a cooling rate of 104°C/S to a thickness of 130°C. It was made into a thin strip of clta.

These ribbons were then heated at 640°C in an Ar atmosphere.

An annealing treatment was performed for 5 hours.

The results of investigating the coercive force iHc of each ribbon obtained are as follows:
As shown in Table 3, all exhibit high coercive force.

Table 3 (Effects of the invention) As stated above, the rare earth permanent magnet according to the invention is
Magnetic properties are much better than conventional materials, and especially for ribbon magnets obtained by the liquid quenching direct plate manufacturing method, workability is greatly improved, and therefore, they are advantageous in terms of cost.

[Brief explanation of the drawing]

FIG. 1 shows the results according to the present invention (Cu, oNi2°C026
) A graph showing the relationship between the annealing wetness and coercive force of a ribbon with a composition of 8oNd2o. Figure 2 is a block diagram showing the manufacturing process of the powder compaction-sintering method. Figure 3 a, b, c , d and e are all schematic diagrams showing the procedure for quenching molten metal into a ribbon, and FIG. 4 is a block diagram showing the manufacturing process of the liquid quenching direct product plate method.

Claims (1)

[Claims] 1. Chemical formula (Cu_aNi_bCo_1_0_0_-_
a_-_b)_1_0_0_-_xR_x However, R:Y
, La, Ce, Pr, Nd, Pm, and Sm; a: 40 to 60 wt%; b: 15 to 35 wt%; x: 5 to 40 wt%. permanent magnet.