JPH07235414A - Magnetic brick - Google Patents

Abstract

PURPOSE:To manufacture a magnetic brick which does not need compression for molding while incorporating heat resistance, and holding sufficient magnetic force and strength with possibility of molding in a desired shape and to manufacture the brick in which no crack occurs in a product when the brick is mounted on a clay product such as a pottery, etc. CONSTITUTION:The magnetic brick comprises 10wt.% of clay powder, and 90wt.% of magnetic powder which is calcined or powdered after primarily burning. A magnetic material-clay mixture powder containing a composition in which 0-90wt.% of the powder which is calcined and then powdered is added to the clay powder is so laminated as to have a composition gradient of magnetic material content in a laminating direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is to mix clay powder and magnetic powder which has been calcinated or pulverized after main baking with water,
The present invention relates to a magnetic brick manufactured by subjecting the mixture to molding, drying and sintering processes.

[0002]

2. Description of the Related Art Magnets are deeply embedded in our lives. After compressing and molding raw material powders such as barium ferrite and strontium ferrite as typical magnets,
Sintered magnets that sinter are known, but a large-scale compression device is required in the compression process, which is the manufacturing process of the sintered magnets, and the die for filling the magnetic powder is also compressed. There are problems in terms of cost, such as having to design a material that can withstand enough.

As other magnets, a bond magnet combined with a synthetic resin such as nylon is known. In recent years, there is an increasing need for composite materials that take advantage of the different properties of materials such as bonded magnets. Taking bonded magnets as an example, when magnets are manufactured using only magnetic powder, magnets with complicated shapes are required. Was difficult to manufacture, but by combining magnetic powder and a synthetic resin such as nylon, it was possible to manufacture even a magnet having a complicated shape.
However, since a synthetic resin is used, deformation due to heat is unavoidable, and there is also a problem of deterioration of mechanical strength at high temperature.

In order to solve the problems of the sintered magnet and the bonded magnet, the present inventor adds clay powder to the magnetic powder so as to have heat resistance and does not require compression for molding. I tried to make something called a magnetic brick. A magnetic brick is a brick that has the ability of a magnetic substance, and the properties of this magnetic brick change greatly depending on the composition ratio of clay powder and magnetic substance powder. If the proportion of magnetic powder in the magnetic brick is high, there is a problem that it will be difficult to mold into the shape intended by the manufacturer, and conversely if the proportion of magnetic powder in the magnetic brick is low. Has a problem in that the magnetic force of the magnetic brick cannot be sufficiently obtained, and the shrinkage rate increases during the drying process which is one of the magnetic brick manufacturing processes, resulting in a significant decrease in dimensional accuracy.

Further, since the main components of magnetic bricks are clay powder and magnetic powder, as an application example of magnetic bricks utilizing the characteristics of these two components, there is an example of attaching magnetic bricks to clay products such as ceramics. However, in this case, even if a magnetic brick is attached, there is a problem that cracks occur at the product joint portion due to the difference in shrinkage ratio between the magnetic powder and the clay powder in the manufacturing process.

[0006]

The object of the present invention is to:
In Claim 1 and Claim 2, there is a need for manufacturing a magnetic brick that can be molded into an intended shape while maintaining a sufficient magnetic force and strength and having heat resistance while not requiring compression for molding. Further, in claim 3, when the magnetic brick is attached to a clay product such as ceramics, it is to produce a magnetic brick in which cracks do not occur in the product.

[0007]

In order to achieve the above-mentioned object, in the present invention, in claim 1 and claim 2, the present inventor has used 10% by weight of clay powder and a magnetic substance which has been calcinated or pulverized after the main calcination. We succeeded in solving the above problems by making the composition of powder 90% by weight. In claim 3, 0 to 90% by weight of the magnetic powder that has been calcinated and pulverized into clay powder.
The magnetic substance-clay mixed powder having the added composition was laminated in such a manner that the magnetic substance content has a composition gradient in the laminating direction, whereby the above problems were successfully solved.

[0008]

According to the first and second aspects, the composition of 10% by weight of the clay powder and 90% by weight of the magnetic powder which has been calcinated or calcinated and then pulverized is used for molding while maintaining heat resistance. As shown in FIG. 1, it does not require compression, retains sufficient strength while being formed into an intended shape, and further, as shown in FIG. 2, shrinkage during drying, which is one of the magnetic brick manufacturing processes. It has become possible to manufacture magnetic bricks while keeping the rate extremely low. In addition, as shown in FIG. 3, 10% by weight of clay powder is excluded, except for magnetic bricks having a magnetic powder composition rate of 100%, which requires compression for molding.
With a composition of 90% by weight of magnetic powder that has been calcinated or pulverized after main firing, a magnetic field of 220 Gauss or more is generated in a test piece of 20 mm × 30 mm × 5 mm, which is much higher than other composition ratios. It has become possible to manufacture magnetic bricks with extremely high magnetic force.

Further, in claim 3, when the magnetic brick is attached to a clay product such as ceramics, it is possible to manufacture a magnetic brick in which cracks do not occur in the product.

[0010]

EXAMPLE An example of the present invention is a method for producing a magnetic brick when a barium ferrite magnetic material is used as the magnetic material powder.

In claim 1 and claim 2, the barium ferrite magnetic powder and the clay powder which have been calcinated or calcinated and then pulverized are made into 10% by weight of clay powder and 90% by weight of barium ferrite magnetic powder. The respective weights are measured, and the measured barium ferrite magnetic powder and the clay powder are sufficiently mixed.

Next, to the mixed barium ferrite magnetic material powder and clay powder, 2 g of water is added to 10 g of the mixed powder of barium ferrite magnetic material powder and clay powder, and they are thoroughly mixed. After the mixing is completed, the mixture is molded in a mold of an arbitrary shape, sufficiently dried for about 2 days until the water content of the molded body completely disappears, and then sintered.

If the sintering temperature is less than 1000 ° C., it is difficult to impart sufficient magnetic properties and compactness.
At temperatures above ℃, partly melted and deformed, and further deterioration of magnetic properties and strength properties due to grain growth is expected.
℃ ~ 1200 ℃ is necessary, preferably 1100 ℃
Is.

If the sintering time is less than 4 hours, it is difficult to impart sufficient magnetic properties and compactness, and if it is 6 hours or more, it is not preferable from the viewpoint of economy and workability. It is necessary, and preferably
5 hours. Finally, the molded body is magnetized by a magnetizer. The magnetic force was over 220 gauss.

The tensile strength and Young's modulus of the sintered bodies obtained in the above examples were measured by TCM-1 manufactured by Minebea Co., Ltd.
It was measured with a 0000 type universal tensile compression tester. A 20 mm × 30 mm × 5 mm test piece was used as a measuring method to perform a bending test with four-point support to measure the tensile strength, and a strain gauge was attached to the test piece to determine the Young's modulus.

The results are shown in FIG. 1. The composition of magnetic bricks is 10% by weight of clay powder and 90% by weight of pulverized magnetic powder after calcination or main calcination, for example, after calcination or main calcination. Compared to a magnetic brick with a composition of 10% by weight of pulverized magnetic powder, the tensile strength is 1.8 times and the Young's modulus is 3.1 times the strength, which is much higher than the magnetic bricks of other compositions. It is clear that Young's modulus can be obtained. As shown in FIG. 2, the composition of magnetic bricks is 10% by weight of clay powder and 90% by weight of magnetic powder that has been calcinated or calcinated after calcination, which is one of the magnetic brick manufacturing processes. The shrinkage rate in drying is 0.54%, which is extremely low compared to other magnetic powder addition rates.

The sintered bodies obtained in the examples were photographed by a JSM-T300 scanning electron microscope manufactured by JEOL Ltd. The photograph is shown in Fig. 4. The composition of 10% by weight of clay powder and 90% by weight of magnetic powder that has been calcinated or crushed after the main firing makes the composition extremely higher than other magnetic powder addition rates. It is clear that high compactness can be obtained.

In claim 3, first, the barium ferrite magnetic substance powder that has been calcinated or calcinated and crushed is mixed with clay powder, and the magnetic substance powder is contained in an amount of 0 to 90% by weight at 10% intervals.
Each of them is weighed so that the barium ferrite magnetic powder and the clay powder are mixed.

Next, the magnetic bricks according to claim 3 are manufactured by the following method in order from a mixed compact of barium ferrite magnetic powder and clay powder having a small content of barium ferrite magnetic powder.

On a flat iron plate, water is added to and mixed with the mixed powder of the barium ferrite magnetic substance powder and the clay powder, and a plate having a thickness of about 1.5 mm is formed using a round bar or the like.
Then, they are laminated in the order of the composition ratio of the barium ferrite magnetic substance powder. As shown in FIG. 5, the stacking method is as follows.
By stacking 10 types of mixed compacts of barium ferrite magnetic powder and clay powder, the composition ratio of barium ferrite magnetic powder and clay powder is inclined.

After the lamination of each layer is completed, the shape is adjusted by punching with a mold having an arbitrary shape. Subsequent manufacturing steps such as drying and sintering are the same as those of the above-mentioned first and second embodiments.

Although the examples of magnetic bricks have been described above, barium ferrite magnetic substance powder is used as an example of the magnetic substance powder, and other magnetic substance powders can be used.

[0023]

As described above, according to the present invention, the composition of claim 1 and claim 2 is 10% by weight of clay powder and 90% by weight of magnetic powder which has been calcinated or pulverized after main firing. This makes it possible to manufacture a magnetic brick that has heat resistance, does not require compression for molding, and is molded into an intended shape while maintaining sufficient magnetic force and strength. Also, laying this magnetic brick on the ground,
By running a vehicle equipped with a sensor for detecting magnetic force on the ground, control of the vehicle by magnetic bricks can be developed in the future.

Further, in claim 3, as an example of a magnetic brick utilizing the feature that a magnetic material contains a clay component,
It is possible to attach magnetic bricks to clay products such as ceramics.

[Brief description of drawings]

FIG. 1 is a diagram showing a change in tensile strength of a magnetic brick due to a difference in composition ratio between a magnetic powder and a clay powder after calcination or main calcination, and calcination after calcination or main calcination FIG. 3 is a diagram showing a change in Young's modulus of a magnetic brick due to a difference in composition ratio between magnetic powder and clay powder.

FIG. 2 is a diagram showing a change in shrinkage rate of a magnetic brick during drying due to a difference in composition ratio between magnetic powder and clay powder that has been calcinated or pulverized after main firing.

FIG. 3 is a diagram showing a change in magnetic force of a magnetic brick due to a difference in composition ratio between a magnetic powder and a clay powder that has been subjected to calcination or calcination after calcination.

FIG. 4 is a photograph of a magnetic brick having a magnetic substance weight percentage of 90% and a magnetic brick having a magnetic substance weight percentage of 100% obtained in Examples taken by a JSM-T300 scanning electron microscope manufactured by JEOL Ltd. is there. The upper figure is a magnetic brick with a magnetic material weight% of 90%, and the lower figure is a magnetic brick with a magnetic material weight% of 100%.

FIG. 5 is a cross-sectional view showing a laminated state of magnetic bricks according to claim 3;

Claims (3)

[Claims] 1. A clay powder and a magnetic powder that has been calcinated or pulverized after main calcination are mixed with water, and the mixture is subjected to molding, drying and sintering processes. And a magnetic brick. 2. A magnetic brick comprising a composition of 10% by weight of clay powder and 90% by weight of magnetic powder that has been calcinated or pulverized after main firing. 3. A magnetic brick formed by stacking a plurality of magnetic bricks according to claim 1, wherein the magnetic forces of the layers of the magnetic brick are different from each other and the magnetic force of the magnetic brick has a composition gradient in the stacking direction. Magnetic brick obtained by stacking on.