JPH0347943A - Rare earth-iron series oxide magnetic material - 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 is directed to rare earth metals having excellent oxidation resistance and high coercive force.
Regarding iron-based oxide magnetic materials.

[Conventional technology]

Many rare earth-transition metal alloys have high coercive force, and are useful as permanent magnet materials, magnetic recording materials, etc.
In particular, those containing Co as a transition metal are known to exhibit excellent magnetic properties. For example, S-C
O alloy and Tb-Fe-Co alloy exhibit excellent magnetic properties and are used as permanent magnet materials and magneto-optical recording materials, respectively.

However, since Co resources are unevenly distributed on the earth, Co is an expensive raw material whose supply is unstable. For this purpose, Co
Rare earth-iron alloys using Fe, which are cheaper than the above, have been developed; for example, in JP-A-57-210934, a rare earth iron alloy manufactured by a liquid quenching method exhibits high coercive force at room temperature. something is disclosed. Further, JP-A-59-46008 discloses a rare earth iron-boron alloy developed as an alloy for high-performance permanent magnets.

[Problem to be solved by the invention]

The rare earth-iron alloy according to the above-mentioned disclosure is easily oxidized and therefore extremely unstable in the atmosphere, so that it is necessary to perform some kind of oxidation-proofing treatment when it is put into practical use.

Furthermore, the inventors of the present invention have confirmed that even if these rare earth-iron alloys are subjected to some kind of anti-oxidation treatment, oxidation cannot be completely prevented. Moreover, the cost associated with this oxidation-proofing treatment is quite high, and the advantage of reducing raw material costs by changing the transition metal from Co to Fe is reduced.

The present invention was made in view of the current state of rare earth-iron alloys as described above, and its purpose is to provide a rare earth-iron oxide magnetic material that has excellent oxidation resistance and high coercive force. .

[Means to solve the problem]

In order to achieve the above object, the rare earth iron-based oxide magnetic material of the present invention contains 60 to 95% by weight of at least one element selected from Pr and Nd, and 125% by weight or less of R.
It is characterized by being crystalline, consisting of at least one element M selected from Co, Ni, and Cu, 0.4 to 5% by weight of oxygen, and the remainder Fe and inevitable impurities.

[Function] In the present invention, R, which is at least one element selected from Pr and Nd, M, which is at least one element selected from Co, Ni and Cu, and oxygen are:
It is an essential element in order to impart high coercive force to rare earth-iron-based oxide magnetic materials. When R is less than 60% by weight and/or oxygen is less than 0.4% by weight, sufficient coercive force cannot be obtained, whereas when R exceeds 95% by weight or oxygen exceeds 5% by weight, saturation magnetization occurs. and the coercive force decreases. Furthermore, when M exceeds 25% by weight, the saturation magnetization decreases.

Further, the magnetic material of the present invention needs to be crystalline, and if it is amorphous, the coercive force decreases.

The magnetic material of the present invention can be obtained by subjecting a melted and pulverized powder, a crystalline alloy ribbon produced by a liquid quenching method, a crystalline thin film produced by a vacuum evaporation method, a sputtering method, etc. to an oxidative heat treatment.

〔Example〕

Examples of the present invention will be described in detail below based on the manufacturing method thereof.

Example 1 Electrolytic iron with a purity of 99% by weight, metal Pr, metal Nd, electrolytic cobalt, metal nickel, and electrolytic copper with a purity of 99.9% by weight were used as raw materials, and the raw materials were high-frequency melted to form an alloy ingot in a copper mold. It was cast in

Next, the obtained alloy ingot was pulverized to an average particle size of 20 μm using a vibration mill, and then the pulverized powder was heat-treated in the air at a temperature of 150° C. for 0.3 to 3 hours to obtain the results of Examples. A rare earth-iron oxide magnetic powder was obtained.

Chemical analysis values (weight%) of the examples obtained in this manner
) and the coercive force measured with a vibrating sample magnetometer, Shikkoe
), magnetization σ1° (eI++
Table 1 shows the values of Curie temperature Tc ('C).

These magnetic powders were left for 100 hours in an atmosphere with a temperature of 80° C. and a relative humidity of 60%, and then the above characteristics were measured again in the same manner. They are shown in Table 1.

Note that the Curie temperature was the same as the above value.

Comparative Example A test was conducted in the same manner as in Example 1, except that the formulation was changed, heat treatment was performed in the air at a temperature of 600° C. for 5 to 10 hours, and the test was not left for 100 hours. The results are shown in Table 2.

Example 2 Using an alloy ingot obtained in the same manner as in Example 1 except for changing the composition, an alloy ribbon was produced by a liquid quenching method using a single roll. Note that the roll circumferential speed was 20 m/sec. This ribbon was heat treated in the air at a temperature of 150° C. for 0.3 to 3 hours.

The thus obtained example was measured in the same manner as in Example 1. The results are shown in Table 3. Further, as a result of X-ray diffraction, all of the samples tested were crystalline. In addition, 100
The Curie temperature after standing for a period of time was similar to the value before standing.

Example 3 A film with a thickness of 1.0 was deposited on a St substrate by vacuum evaporation using an alloy ingot obtained in the same manner as in Example except for changing the composition.
The film was formed by 00 people. The temperature of this thin film was 0.2 at 140°C.
Heat treated in air for ~0.5 hour.

The thus obtained Example was measured in the same manner as Example 1 except for magnetization. The results are shown in Table 4. Further, as a result of X-ray diffraction, all of the samples tested were crystalline. The Curie temperature after standing for 100 hours was the same as the value before standing.

Table 4 Comparative Example 2 Except for changing the formulation and setting the roll circumferential speed to 40 m 7 seconds,
In the same manner as in Example 2, 68.7% Pr5.3% Ni-4,7% Cu-0.8% oxygen Pe″i
i! I got the belt. The coercive force d measured with a vibrating sample magnetometer was 0.6 kOe. Further, as a result of X-ray diffraction, this ribbon contained an amorphous phase.

〔Effect of the invention〕

As explained in detail above, the present invention provides a rare earth-iron oxide magnetic material that has a high coercive force and exhibits superior oxidation resistance in the atmosphere compared to conventional rare earth-iron alloy magnetic materials. provided.

Claims (1)

[Claims] 60 to 95% by weight of at least one element R selected from Pr and Nd, 25% by weight or less of Co, Ni
and at least one element M selected from Cu, 0.
A rare earth-iron oxide magnetic material characterized by being crystalline, consisting of 4 to 5% by weight of oxygen and the remainder Fe and unavoidable impurities.