JP2980254B2 - Anisotropic permanent magnet and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rare earth-iron-boron (R-Fe-B) permanent magnet having anisotropy of magnetic properties and a method for producing the same.

[0002]

2. Description of the Related Art Anisotropic permanent magnets using an alloy in which a rare earth element is 10 to 21 atomic%, boron is 3 to 15 atomic%, and the balance is iron and inevitable impurities are known. Here, one or both of Nd and Pr are generally used as the rare earth element, and both elements have almost the same effect on the magnetic properties of the product. There are the following two methods for imparting anisotropy to this alloy.

[0003] In the first production method, an alloy lump having a predetermined composition is cast, crushed into fine powder of 3 to 10 µm, and the individual powders are oriented in a magnetic field and formed, and then formed in an inert gas atmosphere. Sintering is performed.

[0004] In a second production method, an alloy having a predetermined composition is melted and rapidly solidified by a melt spinning method to obtain a flake-like flake, and this flake is formed by hot pressing.
Further, pressure is applied by hot upsetting to orient the easy magnetization axis in the pressing direction.

[0005] In the magnet manufactured by these methods,
For the purpose of improving the magnetic performance, it has been attempted to substitute a part of R with Dy or a part of Fe with Co.

[0006]

The addition of Co has the effect of increasing the Curie point of the magnet and reducing the demagnetization rate at high temperatures, but the magnetic properties, especially the maximum magnetic energy product, have hardly been improved. . The magnetic properties can be improved by adding Dy, but Dy has a practical problem because it is extremely expensive. Therefore, the present invention relates to R-Fe-B
Magnetic properties of the different laws of the permanent magnet system, both of Japanese to r and θ
For it is intended to improve the maximum magnetic energy product.

[0007]

The basic composition of the raw material alloy used in the present invention is as follows: a well-known rare earth element is 10 to 21 atomic%, boron is 3 to 15 atomic%, and the balance is an iron group element and unavoidable impurities. And the rare earth element is N
One or both of d and Pr are used. As a feature of the present invention, the iron element in the alloy is composed of X atomic% of cobalt, Y atomic% of nickel and the balance of iron, and X and Y are 0 ≦ X ≦ 300 0 ≦ Y ≦ 1 0.5 X + 10Y ≧ 15.

[0008] In the present invention, the product in the r and θ directions
To provide a different law of, by melting the material alloy, which was spherical powder by gas atomization using an inert gas, the front pressing the powder at a temperature of 550 ° C. to 800 ° C.
By deca Engineering, when formed into a predetermined shape at the same time, it gives a different law properties.

As the inert gas, any of argon, neon, helium, or a mixed gas thereof is used. If the size of the spherical powder used for the plastic working is extremely small, it will be oxidized during handling, and if it is too large, it will hinder the plastic working. Therefore, the average particle size is 20 to 100 μm, and the maximum particle size is 30.
It is desirable that the thickness be 0 μm or less. Further, when the forward extrusion pressure engineering, in order to prevent oxidation during heating and processing, the powder was vacuum-sealed into a metal container capable of plastic working, it is desirable to carry out together with the vessel heating and processing.

Generally, in order to impart anisotropy, an appropriate method such as forward extrusion, backward extrusion, ring extrusion, rolling, warm upsetting, etc. can be adopted. Determines the direction in which anisotropy occurs. In order to obtain a remarkable anisotropy for r and θ directions, suitable forward extrusion, pressurization Engineering ratio (sectional area after the cross-sectional area / processing before processing) it is desirable that 4.6 or more.

[0011] In the forward extrusion pressure engineering, the processing speed is too fast, because the strain rate of the material is damaged increases, it is necessary to suppress the strain rate below 0.3. Strain speed V
e is calculated as follows regardless of the mode of processing. Strain E = lnK Strain speed Ve = E / T (sec ⁻¹ ) where k is a working ratio, and T is a residence time from when a certain part in the material enters the working area to when it exits the working area. .

[0012]

In the above two conventional manufacturing methods, no remarkable improvement in magnetic properties was not obtained even if a part of iron in the raw material alloy was replaced with one or both of cobalt and nickel. However, in the present invention, by a gas atomizing method using an inert gas to the powder of the material alloy is adopted, and to further perform heat及beauty forward extrusion pressure Engineering and vacuum sealed the powder into a container, The effect of partial replacement of iron by cobalt and / or nickel is remarkable, and the magnetic properties,
It was possible to greatly improve the maximum magnetic energy product of the r direction and the θ direction especially. Cause of the maximum is considered to be in the powdered material alloy or al forward extrusion machining is until the completion, it was able to suppress oxidation of the raw material powder.

It is known that the effects of Nd and Pr on the magnetic properties of products are almost the same. In other words,
Even if some or all of Nd is replaced with Pr, the magnetic properties of the product hardly change as long as the ratio of the total amount of Nd and Pr in the alloy is constant. FIG. 1 shows the range of the amount of iron to be replaced with cobalt and nickel in the raw material alloy. That is, in the total amount of iron, cobalt and nickel (100 atomic%), the amount of cobalt X (atomic%) and the amount of nickel Y (atomic%)
Is X + 10Y <15, and the cobalt amount X exceeds 30 at%, or the nickel amount Y is 1.5 at%.
When the value exceeds, the magnetic properties of the product are not sufficiently improved.

Furthermore, in the present invention, pole since Umate productivity is adopted good forward extrusion machining method, to be able to industrially advantageously produce an anisotropic magnet of superior performance Was.

[0015]

EXAMPLES Example 1 Various R-Fe-B-based alloys shown as samples 1 to 6 in Table 1 are melted, and each is pulverized to a particle size of 298 μm or less by an argon gas atomizing method. These are each filled in a mild steel capsule having an outer diameter of 28 mm, a length of 35 mm and a wall thickness of 1 mm, and the inside is evacuated and sealed by electron beam welding. This was extruded forward as a billet under the following conditions. Preheating 600 ° C × 5 minutes Extrusion temperature 650 ± 5 ° C Extrusion ratio 4.0 (diameter 28 mm → diameter 14 mm) Strain rate 0.05 per second

Table 1 shows the magnetic properties of the obtained magnet material.
Note that Z is the extrusion direction, r is the radial direction, and θ is the direction orthogonal to r.

[Table 1] Examination of Table 1 reveals that the magnetic properties of Samples 3, 4 and 5 were significantly improved by the addition of Co, whereas Samples 2 and 6
, There is almost no improvement in magnetic properties due to the addition of Co.

Example 2 Various R-Fe-B alloys shown as samples 7 to 9 in Table 2 were powdered under the same conditions as in Example 1, and processed into magnet materials under the same conditions. Table 2 shows the magnetic properties of the obtained magnet material.

[Table 2] Examination of Table 2 reveals that the magnetic properties of Sample 8 are remarkably improved by the addition of Ni, but the magnetic properties of Samples 7 and 9 are hardly improved by the addition of Ni.

Example 3 Various R—Fe—B alloys shown as samples 10 to 12 in Table 3 were powdered under the same conditions as in Example 1 and processed into magnet materials under the same conditions. Table 3 shows the magnetic properties of the obtained magnet material.

[Table 3] Examination of Table 3 shows that Samples 10 and 11 have Ni and Co
The effect of improving the magnetic properties by the simultaneous addition of
In Sample 12, the magnetic properties are rather reduced.

FIG. 1 shows the distribution of the above samples 1 to 12, with the horizontal axis representing the amount of Co X (atomic%) and the vertical axis representing the amount of Ni Y ( atomic%). Reference numerals 1 to 12 in the drawing indicate the sample numbers, and the numbers in parentheses indicate the maximum magnetic energy product (BH) max (MGOe) in the r direction. As is clear from FIG. 1, the range where the maximum magnetic energy product in the r direction is about 14 MGOe or more is a portion surrounded by three straight lines where X = 30 Y = 1.5 X + 10Y = 15. 2, the Co content on the horizontal axis X (atomic%), the vertical axis is a diagram taken r direction of maximum magnetic energy product (MGOe), Ni amount Y is 0
Co amount X in the case of samples 2, 3, 4, 5 and 6 is
Is 15 to 30 atomic%, the maximum magnetic energy product in the r direction shows the highest value. Also, from this , the sample
In the case where the amount of Ni Y is 0.62 atomic% as in 7 and 10,
In this case, as in Samples 8 and 11, the Ni amount Y is 1.24 atomic%.
And the amount of Ni Y is about
Even in the case of 1.7 atomic%, the Co amount X is
Maximum magnetic energy in r direction at 15-30 atomic%
The product can be expected to show a peak.

[0020]

As is clear from the above embodiments,
Advantageous Effects of Invention According to the present invention, the magnetic properties of an R-Fe-B-based magnet alloy can be improved by the addition of one or both of Co and Ni, and a gas atomizing method with good productivity and forward extrusion with good productivity. the adoption of machining methods, can be inexpensively mass-produced r a desired shape, a θ bidirectional different method of magnets.

[Brief description of the drawings]

FIG. 1 is a distribution diagram showing a range of a Co amount X and a Ni amount Y in the present invention.

FIG. 2 is a diagram showing a relationship between a Co amount X and a maximum magnetic energy product in the present invention for each Ni amount Y.

[Explanation of symbols]

 1-12 Sample number

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tomohiro Nishiyama 3007 character, Nakajima character in Shima, Ward, Himeji City, Hyogo Prefecture Inside Sanyo Special Steel Co., Ltd. Chisan Sanyo Special Steel Co., Ltd. (56) References JP-A-63-287007 (JP, A) JP-A-60-189901 (JP, A) JP-A-63-289905 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) H01F 1/00-1/08

Claims (2)

(57) [Claims] 1. A rare earth element is composed of 10 to 21 atomic%, boron is composed of 3 to 15 atomic%, and the balance is composed of an iron group element and an unavoidable impurity. Atomic% nickel and the balance of iron, where X and Y are 0 ≦ X ≦ 30 (atomic%) 0 ≦ Y ≦ 1.5 (atomic%) X + 10Y ≧ 15 (atomic%) It is a molded product of gas atomized powder using active gas, and the maximum magnetic energy in two directions of r and θ
Anisotropic permanent magnet characterized in that the product is improved . 2. A rare earth element comprises 10 to 21 atomic%, boron comprises 3 to 15 atomic%, and the balance comprises an iron group element and an unavoidable impurity. Atomic% is nickel and the balance is iron,
And Y are: 0 ≦ X ≦ 30 (atomic%) 0 ≦ Y ≦ 1.5 (atomic%) An alloy satisfying X + 10Y ≧ 15 (atomic%) is formed into a spherical powder by a gas atomizing method using an inert gas. 550-80 ° C.
Method for producing an anisotropic permanent magnet, characterized in that to obtain a predetermined shape of the molded article by a temperature of 0 ℃ performing forward extrusion pressure Engineering.