JPS5919980B2 - permanent magnet alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a permanent magnet made of rare earth elements and Co, particularly to a permanent magnet with improved temperature dependence of magnetic properties.

RC05, R2C017, R2C07 of intermetallic compounds in the phase diagram of R (hereinafter R is a light rare earth element and one or a combination of two or more of Sm, Pr, Ce, and La) and Co
has the potential to be used as a permanent magnet alloy, and practical alloys include R2C017 to R2C07, mainly ECo5.
Within the above composition range, alloys having a so-called composite structure in which these intermetallic compounds are mixed exhibit particularly excellent magnetic properties.

Various studies have been conducted on permanent magnet alloys consisting of rare earth elements and Co, and the rare earth elements that can be used for this include Y,
Including Sc, La, Ce, Pr, Nd, Pm, Sm called lanthanide numbers from atomic number 57 to 71
, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb,
All elements of Lu are indicated in the general literature.

However, some of the things described in these documents even mention Pm, which does not exist in nature, and even things that are not practical are shown as being usable all at once, and there is no experimental data at all. There isn't. To date, the rare earth elements that have been reported to have practical values as permanent magnet alloys include La, Ce, which is called light rare earth element,
Four types of Pr, Sm and Ce contained as Ce component
Although the magnetic properties of heavy rare earth elements from Eu to Lu have been studied only in alloys of Mitsushi metal and Ce, their properties as permanent magnet alloys have not been reported at all. Light rare earth elements La, Ce, Pr, Sm
,! ■For permanent magnet alloys made of Co, high residual magnetic flux density Br and high coercive force BHC, IHC have been developed.
As a result, an amazing value of 23 to 26 MG0e was obtained for the energy product (BH) max, which is the highest value ever obtained with conventional cast magnet alloys, Alnico9.
This is more than twice that of 11MG0e.

Because they exhibit such excellent permanent magnetic properties, they are used in devices that require strong magnetic fields and devices that require miniaturization. However, as shown in Table 1, the temperature characteristics of this permanent magnet are poor, and the reversible temperature change is more than twice that of AlnicO permanent magnets.

In addition, since there is a large irreversible temperature change, please use the
The temperature is raised to about 50 degrees Celsius to make "heat mustard".
It is usually used after demagnetizing it by about 5%.
For this reason, it has been difficult to use it in environments with severe temperature changes.

Furthermore, it has not been possible to fully utilize its excellent magnetic properties. An object of the present invention is to provide a permanent magnet with small temperature dependence, that is, a permanent magnet whose magnetic properties, particularly magnetic flux, hardly change even if the degree of mud changes.

The present invention improves the temperature dependence of permanent magnet characteristics by substituting a part of the light rare earth element with a heavy rare earth element in a permanent magnet made of light rare earth elements and CO in the composition range from R2CO7 to R2COl7. This is what I did.

In the component range from R2CO to R2COl7, the amount of R is 43 to 23% (shown in weight ratio below), and the remainder is mainly C.
It is O.

The light rare earth element that exhibits the best permanent magnet properties is Sm, and by replacing a part of it with Ce or Ce metal, which is an alloy of Ce, it is possible to create an inexpensive permanent magnet without major deterioration of the permanent magnet properties. Alloys can be obtained.
Therefore, in the present invention, the light rare earth element is based on Sm and includes Ce or Ce metal. Further, excellent properties can be obtained by substituting a part of Sm with Pr, so in the present invention, based on Sm as a light rare earth element, Ce or Ce metal and Pr may be included at the same time. Of course. The heavy rare earth elements used in the present invention are HO, Er, Dy
, Tb with 23-43% O of light rare earth elements, HO, Er
, Dy, Tb, good properties can be obtained.

The temperature coefficient α of the magnetic flux of a rare earth cobalt permanent magnet in which a part of the light rare earth elements is replaced with HO, Er, Dy, or Tb is its absolute value, and 1α1 is 0.04% at -50 to 100°C.
/℃ or below. The reversible temperature coefficient α of magnetic flux used in this specification and drawings is defined as follows.

In other words, the temperature coefficient α in the temperature range of Ta°C to Tb°C is the magnetic flux of the permanent magnet at Ta°C
l), Tb°C, the magnetic flux of the permanent magnet is φb(Maxw
ell), the magnetic flux change during this period △φ−φa−φB
．． Since the temperature change is ΔT-Ta-Tb, 44γ α=]×100/ΔT (%/C).

The permanent magnet of the present invention has Gd in addition to HO, Er, Dy, and Tb.
Even better temperature characteristics can be obtained by adding .

By adding Gd, the vorticity dependence of the vorticity characteristics becomes more linear. For this reason, the temperature coefficient b is small even in a wide temperature range, and the absolute value of α is 0.03%/°C or less from -50 to 200°C. When containing HO, Er, the temperature characteristics at room temperature are improved, and Dy, Tb
When containing , the temperature characteristics at relatively high mud levels are improved. In the case containing HO and in the case containing Er, Dy,
When compared with the case containing Tb, the magnetic properties of the permanent magnet containing HO at room temperature are excellent, particularly in terms of energy product (BH) Max. These heavy rare earth elements may be contained singly in a permanent magnet alloy consisting of a rare earth element and cobalt, or may be added in combination. H
O is present in the permanent magnet alloy consisting of the rare earth element cobalt.
It is appropriate to contain 18%.

The reason for this limitation of ingredients is 3% as shown in the later examples.
This is because additions of less than 1% have no effect of improving temperature characteristics, and additions of 18% or more result in a large decrease in residual magnetic flux density. E
r is 8-17%. Dy is 2-15%, Tb is 2-15%
It is made to contain.

If each element is added below the lower limit, there is no effect of improving the temperature characteristics, and if it is added above the upper limit, the magnetic properties are significantly deteriorated. When a part of Sm is replaced with Ce, Ce
The component limit for is 1-34%.

It is possible to add less than 1% of Ce, but below this amount, C
There is no point in adding e. As the amount of Ce added increases, the raw material cost decreases, but its magnetic properties also deteriorate, resulting in
If it exceeds 4%, it becomes unusable. A part of the CO in the permanent magnet of the present invention is replaced by transition elements Ni, Fe, Cu, and Mn.
Alternatively, a small amount of Si, Ca, Al, or Zr may be added to the alloy.

In this case, 20% of the CO amount is Cu, and 10% of the CO amount is Cu.
Even if % is replaced with Fe or Mn, the effects of the present invention are not adversely affected. According to the present invention, a permanent magnet alloy in which a heavy rare earth element is added to an alloy consisting of a light rare earth element and CO can be produced from low mud to 2.
It becomes a permanent magnet with very little change in magnetic flux due to temperature in the range of 0.00 Celsius.

EXAMPLES The effects of the embodiments of the present invention will be specifically illustrated below with reference to Examples.

Example Sml 3.6%, Ce Mitsushimetal 19%, HO9.
An alloy of 5% CO and 63% CO was previously formed by arc melting.
This was crushed to an average particle size of 3.

It was made into a fine powder of 8 μm.

This was molded in a magnetic field of 8K0e under a pressure of 10t0n/ to obtain a molded body with a diameter of 10mm and a length of 7mm. This molded body was sintered at 1160°C for 1 hour in an Ar flow, then cooled at a rate of 2°C/min, and when it reached 90°C, it was quenched in an Ar flow. Zutsuta.

However, the temperature characteristics of this magnet were determined using a permeance coefficient of 2. The above temperature characteristics are 22.3Sm-1467Ce-63
．． Compared to the irreversible demagnetization rate of 6% and α-0.060%/°C in the case of a permanent magnet alloy having a component of 0Ce, it has extremely excellent temperature characteristics, and this is due to the inclusion of 0Ce. It was obtained.

The above example described the one containing ▲ HO,
As shown in Table 2, other heavy rare earth elements Er, [)Y,
It turns out that Tb and Gd are similarly effective in customizing and fine-tuning the temperature.

Claims (1)

[Claims] 1. 3 to 18% of Ho, 8 to 17% of Er, 2.
These rare earth elements are mixed so that the total amount of one or more elements selected from ~15% Dy, 2~15% Tb, 1~34% Ce or Ce metal, and Sm is 23~43%. 1. A permanent magnetic alloy characterized in that it contains an element, and the remainder mainly consists of Co. 2 3-18% Ho, 8-17% Er, 2 by weight
The total amount of one or more elements selected from ~15% Dy, 2~15% Tb, 3~20% Gd, 1~34% Ce or Ce metal, and Sm is 23~4
A permanent magnet alloy containing these rare earth elements in an amount of 3%, with the remainder mainly consisting of Co.