JPH01308757A - Magnet-type closed container - Google Patents

Abstract

PURPOSE:To improve a productivity and a volume-efficiency of a hermetically closed container and enhance a magnetic suction force of a magnet used therein, by employing a magnet of rare earth metal which is produced by coating a cast ingot with a ferromagnetic material, hot-machining the coated ingot at a particular temperature and then subjecting the machined product to heat-treatment. CONSTITUTION:A hermetically closed container is composed of a container body 2 containing a permanent magnet therein and a lid member which encloses ferromagnetic substance at a position aligned with that of the permanent magnet 1. A magnetic attraction force created between the permanent magnet 1 and the ferromagnetic substance serves to produce a hermetic seal between the container body 2 and the lid. The permanent magnet 1 is produced as follows. Rare earth metal such as yttrium and boron are weighed in a given procedure. The mixture is melted and cast to obtain a cast ingot which is then sheathed with pure iron. The sheathed ingot is subjected to hot-elongation at a temperature of 500 deg.C to 950 deg.C, where a machining rate is about 80%. The elongated product is heat-treated at a temperature of 250 deg.C to 1,000 deg.C for 24hr and cut and ground to produce the magnet fittable to the container body 2. Thus, the permanent magnet 1 suitable for the hermetically closed container and having a sufficient coercive force is obtainable only by subjecting to heat treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic sealed container used for storing and transporting foods, medicines, industrial materials, and the like.

[Prior Art] As described in Japanese Utility Model Publication No. 59-1963 and shown in Fig. 2, a magnetic sealed container was known in which a large number of unidirectionally magnetized ferrite magnets were fixed and the container was sealed by its attractive force. .

[Problem M to be solved by the invention] However, conventional magnetic airtight containers generally use ferrite magnets as permanent magnets, so they do not have sufficient suction force, resulting in poor airtightness. In this case, the shape of the magnetic circuit section becomes large, resulting in the overall shape of the container becoming large relative to the capacity of the container.

On the other hand, a case will be described in which a rare earth magnet such as a rare earth iron boron sintered magnet or a bonded magnet, which has a large energy product, has a sufficient attractive force, and has a low raw material cost, is used in a magnetic sealed container. R-TM-B rare earth magnets manufactured by the sintering method require a process of turning the alloy into powder;
TMB alloys are very active against oxygen, so when they are made into powder, their surface area increases and oxidation becomes intense, which inevitably increases the oxygen concentration in the sintered body. When molding the powder, molding aids such as zinc stearate must be used,
Although this is removed before the sintering process, several percent remains in the magnet in the form of carbon.

This carbon is undesirable because it deteriorates the magnetic performance of the R-TM-E magnet.

The molded body after press molding with the addition of a molding aid is called a green body. This is very fragile and difficult to handle, and therefore, it is a major drawback that it takes considerable effort to neatly arrange them in the sintering furnace.

Furthermore, in order to obtain an anisotropic magnet, press molding must be performed in a magnetic field, which requires large equipment such as a magnetic field power source and a coil.

Because of the above drawbacks, generally speaking, R-TM-B
Not only does the production of sintered magnets require expensive equipment, but production efficiency also deteriorates and the manufacturing cost of the magnets increases.
It is difficult to say that it is possible to take advantage of the advantages of B-series magnets.

In order to manufacture bonded magnets, a vacuum melt spinning device is used, but the vacuum melt spinning method has very poor productivity, and this device is currently expensive.

Further, since the vacuum melt spin method is isotropic in principle, the energy product is low, and the squareness of the hysteresis loop is also poor, which is disadvantageous in terms of temperature characteristics and restrictions on the magnetic circuit configuration.

Anisotropic magnets and stones can be obtained by hot pressing amorphous magnetic powder produced using a vacuum melt spin device and then hot pressing the bulk material again.
Since the hot press is used in two stages, it is undeniable that it will be extremely inefficient when considering actual FFI production.
Furthermore, in this method, at high temperatures, for example, 800° C. or higher, the crystal grains become significantly coarsened, resulting in an extremely low coercive force, making it impossible to produce a practical permanent magnet.

As mentioned above, since magnets are expensive, the cost of the sealed container itself has also increased, and it has been used in only a limited number of products.

Therefore, the present invention is intended to solve these problems, and its purpose is to create a high-performance, low-cost R-T M- which uses melting and casting as the basic process, and also uses hot working and heat treatment. By using B-based permanent magnets, it is possible to provide a magnetic sealed container that has a strong attractive force and is low in cost.

[Means for Solving the Problems] In order to solve the above problems, the magnetic sealed container of the present invention has the following features:
Rare earth elements (including yttrium) as permanent magnets
A process of melting and casting an alloy whose basic components are , transition metals, and boron, followed by covering the cast ingot with a soft magnetic material, hot working at a temperature of 500°C or higher, and then heat treatment at a temperature of 250°C or higher. It is characterized by the use of rare earth magnets produced by

In addition, the magnetic sealed container of the present invention is used as a permanent magnet by melting an alloy whose basic components are rare earth elements (including yttrium), transition metals, and boron, and bonding it with a soft magnetic material or a magnet. It is characterized by using a rare earth magnet manufactured by performing a process of casting into a mold made of the material, hot working the cast ingot together with the mold at a temperature of 500°C or higher, and then heat treatment at a temperature of 250°C or higher.

[Example 1] Fig. 1 shows a perspective view of an embodiment of a magnetic sealed container according to the present invention. This is an example in which a permanent magnet 1 whose main components are rare earths, transition metals, and boron is enclosed in a sealed container body 2. . A soft magnetic material is sealed in the sealed container lid at a position corresponding to the permanent magnet sealed in the sealed container body, which generates a magnetic attraction force between the permanent magnet and the sealed container body and the lid. Table 1 shows the composition of the alloy produced according to the present invention.

Table 1 However, the composition of the magnet is not limited to those shown in Table 1, and the rare earth metals include Y, La, and Ce.

Pr, Nd13m% Eu% Gd, Tb%
DV.

Ho, Er, Tm, Yb, Lu are listed as candidates,
One or a combination of two or more of these may be used. The highest magnetic properties are obtained with Pr. Practically, therefore, Pr, Pr-Nd, Ce-Pr-Nd alloys, etc. are used.

Candidates for the transition metal include Fe% CO1Ni% Cu, etc., and one or more of these may be used, or a combination of two or more of these may be used. In addition, small amounts of additive elements such as heavy rare earths Dy, Tb, etc., Al,
Si, Mo, Ga, etc. are effective in improving coercive force.

The main phase of R-TM-E permanent magnet is R2TM + 4B
It is a compound phase. Therefore, R is 8j! If it is less than %, it will no longer form a superposition compound and high magnetic performance will not be obtained.
On the other hand, when R exceeds 30 atomic %, the nonmagnetic R-rich phase increases and the magnetic properties deteriorate significantly.

Therefore, the range of R is 8 to 3 (l% is appropriate).

However, in order to form a cast magnet, it is preferably 8 to 25 atomic %.

B is an essential element for forming the R2TM Ia B compound phase, and if it is less than 2 atom%, it becomes a rhombohedral R-TM system, so a high coercive force cannot be expected, and if it exceeds 28 atom%, B The amount of non-magnetic phase containing increases, and the residual magnetic flux density decreases significantly. However, as a cast magnet, B is preferably 8j! If it exceeds this value, a fine R2T M 14 B compound phase cannot be obtained unless special cooling is performed, and an appropriate coercive force cannot be obtained.

A1. Ga etc. show the effect of increasing the coercive force. However, since A1 and Ga are non-magnetic elements, increasing the amount of addition decreases the residual magnetic flux density. %, the residual magnetic flux density becomes lower than that of hard ferrite, and the purpose of the rare earth magnet cannot be achieved. Therefore, the amount of A1 added is preferably 15 atomic % or less, and the amount of Ga is 6 atomic % or less.

Rare earths, transition metals, and boron were weighed to have the composition shown in Table 1, melted and cast in an induction heating furnace, the cast ingot was covered with a sheath of pure iron, and this was hot rolled at 950°C. . The machining rate is about 80%. then 1000
℃ for 24 hours, cutting and polishing were performed to produce a magnet for a magnetic closed container. Table 2 shows the magnetic properties of the permanent magnet manufactured in this example.

Table 2 (Example 2) After cooling, a lid was welded to the top, heated to 950° C., and hydrostatic extrusion was performed. This is an example in which heat treatment and cutting and polishing were then performed.

Table 3 shows the magnetic properties of this yoke-integrated magnet.

[Effects of the Invention] As described above, the sealed magnet container of the present invention can be used as a permanent magnet by simply heat-treating a cast ingot without going through the steps of crushing and sintering, and can be used as a permanent magnet. Since the production process can be significantly reduced and the productivity of permanent magnets can be increased, the productivity of magnetic sealed containers can also be greatly improved.

Furthermore, as a magnetic property, the maximum energy product of Example 1
Since it has a magnetic property of 23-24 (MGOe), about 10 times that of conventional ferrite magnets, it is possible to realize a magnetic sealed container with strong attractive force and good volumetric efficiency.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a magnetic sealed container according to the present invention. FIG. 2 is a perspective view of a conventional magnetic sealed container. 1...Rare earth magnet 2... Airtight container body 3...Sealing material that's all Applicant: Seiko Epson Corporation

Claims (2)

[Claims] (1) In a magnetic sealed container in which a permanent magnet is enclosed in either the edge of the container body or the edge of the lid, and a magnetic material is enclosed in the other, the permanent magnet is a rare earth element (however, A process of melting and casting an alloy whose basic components are yttrium (including yttrium), transition metals, and boron, then covering the cast ingot with a soft magnetic material, hot working at a temperature of 500°C or higher, and then hot working at a temperature of 250°C or higher. A magnetic sealed container characterized by using a rare earth magnet manufactured through heat treatment. (2) In a magnetic sealed container in which a permanent magnet is enclosed in either the edge of the container body or the edge of the lid, and a magnetic material is enclosed in the other, the permanent magnet is a rare earth element (however, The process of melting an alloy whose basic components are yttrium (including yttrium), transition metals, and boron, and casting it into a mold made of a soft magnetic material or a material used in conjunction with a magnet;
A magnetic closed container characterized by using a rare earth magnet produced by hot working a cast ingot together with the mold at a temperature of 500°C or higher, and then heat treating it at a temperature of 250°C or higher.