JPS61260610A - Manufacture of permanent magnet - Google Patents

Abstract

PURPOSE:To obtain the maximum energy product by a method wherein a multistage aging treatment is repeated a plurality of times in the process wherein the alloy, which is adjusted in such a manner that it is composed of R at 23.0-25.5wt%, Cu at 3.0-5.0wt%, Zr at 2.0-5.0wt% and Co for the remainder, is brought into the state of magnet. CONSTITUTION:A sintering process is applied to the material consisting of R (R is at least a kind of rare-earth element) at 23-25% in percentage by weight, Cu at 4.0-5.0%, Fe at 13-15%, Zr at 1.5-4.0%, and Co at the remaining percentage, and after said sintering process is finished, a multistage aging treatment is repeated twice or more at the temperature range of 400-850 deg.C. As a result, the magnet having high coercive force and a high energy product can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an intermetallic compound of rare earth metal R and 00, particularly C”
The present invention relates to a manufacturing method for improving 2-17 series permanent magnets including t'e'fc.

Rare earth cobalt grinding stones produce a much larger magnetic energy product than conventional alnico magnets and ferrite magnets, so demand for them is rapidly increasing. Initially, the use of rare earth cobalt magnets was limited to ultra-small products such as pickups, watches, and clocks due to high material costs, but today they are used as core materials for various industrial and consumer electrical and electronic devices. It appears to be playing an important role. Specifically, we are expanding the field of application to small motors, small speakers, headphones, step motors, VOM, etc. from the idea of miniaturizing, high performance, and energy saving electronic equipment including audio equipment, and will continue to do so in the future.
A (office automation), M! (home electronics), FA (factory automation),
Demand is expected to gradually expand to include automotive electrical components and medical equipment.

[Summary of the invention]

The present invention comprises O~25% R (R is at least one rare earth element, 4.0 to 5.0 Ou, 13% by weight)
When producing a sintered permanent cornerstone consisting of ~15% F#, 1.5~4.0% Zf, and the balance substantially Co, at between 850'C and 400°C after sintering. By repeating multi-stage aging treatment two or more times, it is attempted to obtain a magnet with high coercive force and high energy product.

[Conventional technology]

It is known that an intermetallic compound of rare earth (R) and cobalt is suitable as a permanent magnet, and the first permanent magnet used was ROQ, and 5fiOQ was the most unusual. Subsequently, S fn@O01q-based compounds, which have a small proportion of cobalt, were classified as having a higher energy product. This R1001
Magnetization of 7-series alloys has been carried out by adding Cu' to generate a precipitated phase in the alloy to obtain coercive force.

However, since adding nonmagnetic O%'6 causes a decrease in saturation magnetization, attempts have been made to increase saturation magnetization by introducing F#. However, there is a problem in that an excessive increase in the amount of F# decreases the coercive force, although it increases the saturation magnetization.

7. Addition of a fifth element such as 2τ has been attempted as a method to improve the decrease in coercive force caused by addition, and a typical composition thereof is S25.5Wt-F615wt%-Ou8wt%-Zr.
1, 8 Wt%-○O remainder is well known. However, with this composition, although a higher maximum energy product than A MGO can be obtained, the carrier crab Ho can only obtain a maximum energy product of about 70,000. For this reason, it is difficult to use at operating points with low permeability, and the shape of the material is restricted, which is a major obstacle to expanding demand. Furthermore, from a material standpoint, there is a strong desire to develop a magnet with even higher magnetic properties (for example, (B H) saw ) f.

JP-A-56-1 was developed to improve these points.
It is 56785. In other words, the weight percentage is ~28Wt
R (Rij: rare earth metal) and 1 to 5 wt% Ow
and 1 to 35 wt% F6 and 0.6 to 6. OWt Chi's M
(M is produced by crushing, magnetic field forming, sintering, solution treatment, and aging treatment of an alloy consisting of N6.Zr, '1' (, f and one or more of This is the way to do it.

[Problem that the invention seeks to solve]

The typical composition of the magnet described in JP-A-56-15785 is 5m25wt%-Ou4wt%-7g20wt%-Z
Although a high coercive force can be obtained with the remainder of r2.2wt%-O6, the desired high energy product cannot be obtained due to slight variations in manufacturing conditions. The reason for this is that aging treatment is performed to increase the coercivity crab HOi, but by performing isothermal long-term treatment at around 850°C,
This is because the squareness of the demagnetization curve is significantly reduced.

The present invention was made in view of the above circumstances, and
R, OO, including O-body, F#, and Zrf.

The main purpose is to improve the properties of the system.

[Means for solving the problem] The inventors conducted intensive research to solve the above problem, and found that swb and F
The gist of this is to devise an aging treatment method to reduce # than the conventional typical composition and at the same time improve coercive force.

In other words, the final composition of the permanent magnet is 1LZ3.0~25
．． 0wt%, Cu8, O~5, OWE%, 2r2
, 0 to 5,01 Ft%, with the balance being Co.

By repeating the aging treatment multiple times, it is possible to easily produce a high maximum energy product without reducing the squareness of the Br and demagnetization curve (obtaining a coercive crab HQt equivalent to that of a 1-5 magnet) and at the same time easily producing a high maximum energy product. It is based on finding a method.

Next, the present invention will be explained in detail with reference to Examples.

[Example 1] q! so that the final composition becomes the cornerstone shown in Table 1! ! The raw materials were adjusted and an ingot (1) was produced using a high frequency melting furnace. NOl,
and No. 2 are conventional alloy compositions, and No. 8 is a composition representative of the present invention. Each ingot is powdered with an average particle size of 8 microns, and then compression molded by applying a magnetic field of 10 KOe to orient the powder. After this, 1170 ~ in vacuum
b Sintering was performed for 1 hour, and then solution treatment was performed at 1150°C to 1190°C for 2 hours. Furthermore, each sample was subjected to multi-stage aging treatment under the following conditions.

No. 1 is 850℃ x 1 hour, 700℃ x 1 hour, 600℃
℃×2 hours, 500℃×8 hours, and 400℃×6 hours. No.2 is 850'C x 50 hours, 700℃ x 1
time, 600℃ x 2 hours, 500℃ x 8 hours and 400℃
℃×5 hours. All of them are determined by a known aging method.

Inventive alloy No. 8 was subjected to the same multi-stage aging treatment as No. 1 repeatedly several times. Table 1 shows the magnetic properties of the product thus obtained.

Clothes-1 From the results of the second variation, the maximum energy product of the conventional alloy Nol is (BH) TluoLw 27MGO can be obtained but 00
Holding Crab HO is as low as 7KO$. Also, conventional alloy 1J O2
obtains a coercive crab HO of 11KO#, but the maximum energy product is (BH) curse 2X25, f3 MGO and NO
Inferior to I. This is due to the long initial aging process.
This is due to a decrease in Br and a decrease in the squareness of the demagnetization curve, although this increases. In comparison, the alloy of the present invention can easily have a high HO and a high maximum energy product. In particular, after sintering, repeating multi-stage aging several times significantly increases the HC.For example, if aging is repeated for 5 days, (BE)r
NoLZ exceeds 32 MGO'i, which shows that the effect of the present invention is large.

[Example 2] Six types of alloys whose final compositions were adjusted as shown in Table 2 were crushed, formed, sintered, and molded under the same conditions as described in Example 1.
Solution treatment was performed. And the aging treatment is the present invention alloy N0
The same pattern as the J3 alloy was used, and the number of repetitions was 8 times. Table 2 shows the results of measuring the magnetic properties after aging treatment.

Cloth-2 As is clear from Table-2, the upper limit of the appropriate am range for the alloy of the present invention is 26 Wt%, and the lower limit is 23 wt%. The reason for this limitation is that, as is clear from Sawa, if the metal falls out of this range, the helical value decreases or the squareness of the demagnetization curve decreases, resulting in a lower maximum energy product than the conventional alloys No. 1 and NO2. It is.

[Example 8] In order to determine the appropriate amount of F in the present invention alloy ν, an alloy 59 whose final composition was adjusted as shown in Table 8 was prepared, and the same manufacturing method and treatment as in Example 2 were carried out. After applying this, the magnetic properties of each were measured.

Table 8 As is clear from Table 8, the present invention alloy N o 1.1, N
It can be seen that O 12 and N O 13 have higher coercivity HO and higher maximum energy product than the conventional alloys, and the effect of the invention is remarkable. However, when the F content is less than 13 and more than 16 wt%, the coercive crab HO becomes low, and
The squareness of the demagnetization curve deteriorates significantly, and the maximum energy product decreases significantly. From the viewpoint of maintaining properties superior to conventional alloys, the range of OW t To is limited to 13 wt % to 15 wt %.

[Example 4] What is the appropriate amount of aS in the alloy of the present invention in Examples 2 and 8? 6 amounts were determined, and in order to determine the appropriate amount of C1L, five types of alloys were prepared whose final compositions were adjusted to have the compositions shown in Table 4. The sample preparation method was the same as in Example 2.8. The obtained magnetic properties are shown in t-94.

As is clear from Table 4, N o , 16 , 17 , 18
In all of the alloys of the present invention, the carrier crab H5 exceeds 10 KOs and the maximum energy product also exceeds 30 MGO,11, indicating that the effects of the alloys of the present invention are remarkable. However, when the amount of O1L becomes 2 Wt, the decrease in HO is large and the squareness of the demagnetization curve decreases, so the maximum energy product is inferior to that of the typical composition of conventional alloys. Also, the amount of 014 is 6w
At t%, the maximum energy product drops to 6°5 MGO- due to the effects of a decrease in BT and a decrease in the squareness of the demagnetization curve. Therefore, the O content range is limited to 8°O to 5.0wt%. From the above examples, S? The ranges of l'L, F#, and Ou were determined, but regarding the content of 2τ, 1
．． This is because when the weight is less than 5 wt%, the Bf decreases significantly (at 4,4 wt% or more, the Bf decreases significantly, and the effects of the present invention cannot be exhibited).

〔Effect of the invention〕

The conventional high coercive force type 2-17 arsenite is
Although the low holding power, which was a drawback of the 7 series, has been improved,
B? This significantly impairs the squareness of the demagnetization curve and makes stable production difficult, posing a major practical obstacle. As a result of various experiments and studies on the composition of the present invention, it has been found that reducing the S and F# contents compared to conventional alloys is effective in improving properties. Furthermore, by repeating multi-stage aging treatment, it is possible to obtain a coercivity crab (○) comparable to that of the 1-5 series without reducing the BT and the squareness of the demagnetization curve, and at the same time achieve a 1-higher energy product. be.

The exposed surface of the present invention made in this way is not limited by the material shape even at the operating point where the permeance is low, which was a drawback of the 2-17 series magnet, and also has good temperature characteristics. It has also become possible to use it for communication devices that require The industrial value of the present invention is extremely great in today's world, when electrical and electronic equipment for various industries and consumer use is desired to have higher precision, be lighter, thinner, and smaller.

Although the present invention has been described above based on Examples, the present invention is not limited to the Examples and described aspects. In the examples, 8ty4i was used as a representative example of R, but the effects of the present invention are not limited to this composition. In other words, similar to what has been attempted with conventional alloys, a part of 8
0$, Nd, P.

, the same effect can be obtained by using R (rare earth elements) such as +11
゜It is something that brings.

that's all

Claims (1)

[Claims] 23 to 25% R (R is at least one rare earth element), 4.0 to 5.0% 0μ, and 13 to 15% by weight
When manufacturing a sintered permanent magnet consisting of % F_6, 1.5 to 4.0% Zr, and the balance substantially Co, multi-stage aging treatment is performed between 850°C and 400°C after sintering. 2
A method for manufacturing a permanent magnet, characterized by repeating the process more than once.