JPH10310842A - Production of terbium-containing magnet alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently reutilize an alloy as the raw material for an Nd series magnet at high yield by melting a used sputtering target and scrap for photoelectro-magnetic use contg. Tb together with an alloy contg. Nd. SOLUTION: As a sputtering target for forming magnetic thin coating for photoelectro-magnetic recording use, an alloy contg. Tb, Fe, Co, Cr or the like is used. Since both scrap generated at the time of producing this sputtering target and the used sputtering target contain Tb, for effectively utilizing them, they are melted to form into a Tb-Fe-Co-Cr-contg. alloy. This Tb-contg. alloy is melted together with an Nd-Fe-B series alloy for utilized as the raw material for a magnet alloy contg. Nd, Fe, B, Co or the like to produce a magnet alloy. By substituting Tb with a part of Nd in the magnet alloy, it can efficiently, and effectively be reutilized as the Nd-Fe-B series magnet alloy excellent in coercive force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a magnet alloy containing Tb.

[0002]

2. Description of the Related Art Magnetic thin films for magneto-optical recording films are produced by a sputtering method, and a sputtering target (hereinafter abbreviated as a target) is made of an alloy such as Tb, Fe, Co, Cr, etc., and is non-uniform by sputtering. And was replaced with a new one before the backing plate was sputtered. By optimizing sputter conditions,
Efforts are made to wear more evenly, but usually about 1/2 to 2/3 of the target is replaced unused. Also, when this target is manufactured, alloy scrap is generated. To recover useful metals such as Tb from this used target and alloy scrap, remove the target from the backing plate, grind and remove the oxide on the target surface, melt it, dissolve in acid, and dissolve in oxalic acid. For example, a method of adding a precipitant such as the above and recovering as oxalate Tb is known.

[0003]

However, in the above method, although an alloy having the same composition as the target composition can be obtained, it is difficult to control the structure, and an alloy having a composite structure of Tb and Tb-Fe which is widely used at present is used. It cannot be used as a target material. Further, there is a problem that oxygen is increased, and a magneto-optical recording film manufactured using a used target as a raw material cannot avoid deterioration in characteristics. The other method is effective for recovering expensive rare earth components, but has problems such as acid dissolution and filtration and recovery of the precipitate, and further, when used as a metal, it needs to be reduced. There has been a demand for a simple and effective method of utilizing used targets and alloy scrap.

[0004] On the other hand, it is known that coercive force is improved by replacing a part of Nd with Tb in an Nd-based magnet. However, Tb metal has not been widely used industrially because of its high cost.

[0005]

Means for Solving the Problems In view of the above problems, the present inventors have made intensive studies on how to effectively use a used target and to improve the properties of Nd-based magnets, and as a result, completed the present invention. That is, the present invention is a method for producing a Tb-containing magnet alloy, comprising melting a used sputtering target for magneto-optics containing Tb metal with at least Nd, Fe, B or an alloy containing these. Hereinafter, the present invention will be described in detail.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is to use a used target containing Tb as a raw material for producing a magnetic alloy without special treatment as it is, and more specifically, to use the target removed from a backing plate. In producing the Nd-Fe-B-based magnet alloy, the used target is melted together with the metal material for the magnet to produce an Nd-Fe-B-based magnet alloy to which Tb is added. In addition, Tb metal-containing alloy scrap generated when manufacturing this target can also be used as a raw material for producing a magnet alloy, like the used target.

The used target or alloy scrap used in the present invention is composed of about 30 to 50 wt% of Tb, about 40 to 60 wt% of Fe,
o Tb-Fe-Co alloy containing about 3-10wt%
b about 40-60 wt%, Fe about 40-60 wt%, Co about 3-10 wt%, Cr
A Tb-Fe-Co-Cr alloy containing about 0.5 to 5 wt% is preferable. Fe is the main component of the magnet, and Co is
Is effective in improving coercive force, and there is also an advantage that a used target has a greater effect of improving magnet properties than adding Tb metal alone to a magnetic alloy. The content of oxygen is preferably 0.5% by weight or less so as not to deteriorate the magnetic properties.

[0008] The magnet raw material to be melted together with the used target and alloy scrap is at least Nd, Fe, B or an alloy containing these. Examples of other metal raw materials include Al, Co, and Dy.

The melting may be performed by a conventionally known method.
From the viewpoint of mass production, it is preferable to melt in a high frequency induction melting furnace. In addition, in order to facilitate the composition adjustment, it is preferable that the used target and the alloy scrap are melted in advance to form a homogeneous recovered alloy, and then melted together with the metal raw material for the magnet.

[0010]

Next, an embodiment of the present invention will be described. Example 1 When a magnetic thin film for a magneto-optical recording film was prepared by a sputtering method, a used target containing Tb was peeled off by heating a backing plate of a sputtering apparatus, and the attached bonding agent was polished. Removed. These ten used targets are melted in a high-frequency induction melting furnace,
A homogeneous recovered alloy A was obtained. This composition is Tb41wt%, Fe52wt
%, Co 7 wt%, and oxygen 0.30 wt%. Separately, 6 kg of alloy scrap containing Tb generated during the production of the magneto-optical target was melted together with the five used targets in a high-frequency induction melting furnace to obtain a homogeneous recovered alloy B. This composition is Tb 46wt%, Fe 45wt%, Co
The content was 7 wt%, Cr 2 wt%, and oxygen was 0.28 wt%.
The recovered alloy A, Nd, ferroboron, electrolytic iron, and aluminum were blended in predetermined amounts to obtain the composition shown in Table 1, and were melted in a high frequency induction melting furnace to produce a magnet alloy. According to a known magnet manufacturing method, the magnet was subjected to pulverization, molding, sintering and aging to produce a sintered magnet alloy, and its magnetic properties were measured. Table 1 shows the measurement results.

[0011]

[Table 1]

Example 2 A magnet alloy was prepared and the magnetic properties were measured under the same conditions as in Example 1 except that the recovered alloy B was used and the composition shown in Table 1 was used. Table 1 also shows the measurement results.

Example 3 A magnet alloy was prepared and the magnetic properties were measured under the same conditions as in Example 1 except that the recovered alloy A was used and the composition shown in Table 1 was used. Table 1 also shows the measurement results.

Example 4 A magnet alloy was prepared and the magnetic properties were measured under the same conditions as in Example 1 except that the recovered alloy B was used and the compositions shown in Table 1 were used. Table 1 also shows the measurement results.

Comparative Example 1 A magnet alloy was prepared and the magnetic properties were measured under the same conditions as in Example 1 except that the recovered alloy was not used and the compositions shown in Table 1 were used. The results are also shown in Table 1.

Comparative Example 2 A magnet alloy was manufactured under the same conditions as in Example 1 except that the recovered alloy was not used and the composition was the same as that of Example 1 except that 2 wt% of Tb metal was used, and the magnetic properties were measured. did. The results are also shown in Table 1.

[0017]

According to the present invention, an Nd-Fe-B sintered magnet having excellent magnetic properties, particularly excellent coercive force, can be obtained. Also expensive
The same excellent magnetic properties as when using Tb metal can be obtained, and the industrial value is very large.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hitomi Tokui 2-6-1 Otemachi, Chiyoda-ku, Tokyo Shin-Etsu Chemical Co., Ltd. (72) Inventor Kenji Yamamoto 2-1-1 Kitafu, Takefu-shi, Fukui Prefecture No. 5 Shin-Etsu Kagaku Kogyo Co., Ltd. Magnetic Materials Research Laboratory

Claims (5)

[Claims] 1. A method for producing a Tb-containing magnet alloy, comprising melting a used sputtering target for magneto-optics containing Tb metal with at least Nd, Fe, B or an alloy containing them. 2. A method for producing a Tb-containing magnet alloy, comprising melting a scrap of magneto-optical alloy containing Tb metal with at least Nd, Fe, B or an alloy containing these. 3. The method for producing a Tb-containing magnet alloy according to claim 1, wherein the used sputtering target and / or alloy scrap is a Tb—Fe—Co alloy. 4. The method for producing a Tb-containing magnet alloy according to claim 1, wherein the used sputtering target and / or alloy scrap is a Tb-Fe-Co-Cr alloy. 5. The method for producing a Tb-containing magnet alloy according to claim 1, wherein the melting is performed in a high-frequency induction melting furnace.