JPS58199722A - Permanent magnet material containing ca, pb and la oxides - Google Patents

Abstract

PURPOSE:To obtain the titled material comparable or superior to a known magnet contg. Ba or Sr in magnetic characteristics and capable of being easily provided with directional properties by a mechanical method by substituting PbO for part of CaO in a permanent magnet material contg. Ca and La oxides. CONSTITUTION:This permanent magnet material contg. Ca, Pb and La oxides has a chemical composition represented by a formula (CaO1-xPbOx.6Fe2O3)100-y (La2O3)y (where 0.2<=x<0.8 and 2<=y<=5). The magnet material is obtd, by substituting PbO for part of CaO in a Ca-La ferrite magnet made of a compound represented by a formula (CaO.6Fe2O3)97(La2O3)3, and it is comparable or superior to a conventional known Ba or Sr ferrite magnet in magnetic characteristics and is easily provided with directional properties by a mechanical method.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a Ca-pb-1-a-based oxide magnet material, and more specifically, it has magnetic properties equivalent to or higher than conventionally known barium-based or strontium-based ferrite magnets, Furthermore, the present invention relates to an oxide permanent magnet that has the remarkable property of being easily mechanically oriented.

Barium-based or strontium-based ferrites are well known and widely industrialized as ferrite oxide and physical permanent magnets, but research reports have been made on many other systems. For example, the present inventors first discovered that C
a-La ferrite (Ca O-6F e, O,) f
It was discovered that the 7(L ax03)s compound has magnetic properties equivalent to those of the currently used 13a, 3r type fluorite magnets,
Furthermore, we also proposed an oxide permanent magnet in which part of the CaO was replaced with BaO or SrO (Japanese Patent Laid-Open No. 55-130862).
After that, the present inventors carried out intensive experimental research on various materials and conditions with the aim of improving the magnetic properties of the Ca (a-based) l-light magnet, and as a result, they replaced a part of CaO with PbO. The oxide magnet material is mechanically oriented easily (
The present invention was completed based on the discovery that anisotropy is produced even by an isotropic maxillary construction method that involves simply molding with a press.

That is, the object of the present invention is to easily obtain mechanical directionality (anisotropy), to have magnetic properties comparable to or better than conventionally known Ba and Sr magnets, and to be able to reduce the calcination concentration. The object of the present invention is to provide a new oxide permanent magnet material that can be easily subjected to various treatments.

The present invention, which can achieve such objects, is based on (Ca
07-XP b O, t-6F e, O, ), , -5
(LalO,).

Ca-Pb-L, which is represented by the compositional formula, and whose main component is a chemical composition in which X is in the range of 0.2 to 0.8 and ■ is in the range of 2 to 5.
This is an a-based oxide permanent magnet material.

The present invention will be explained in more detail below.

The present invention is basically Qa-1a as described above.

In the oxide permanent magnet material, a part of the calcium oxide is replaced with lead oxide, (CaO,-,
Pb O, -6F e, Io, ) + -, -, (La,
0. ).

It is expressed by the chemical formula: Here, the content 1y (mol %) of lanthanum oxide is selected in the range of 2 to 5. The reason for this is that if the content of lanthanum oxide is less than 2 mol%, the crystal form of the compound represented by the above chemical formula will not be hexagonal (magnetobrambite system), and the magnetic properties will be significantly reduced. The content of lanthanum oxide is 5
This is because even if the amount exceeds mol %, the magnetic properties deteriorate, and addition of a large amount of valent lanthanum oxide is not preferable from an economical point of view. In terms of magnetic properties, it is most preferable for the content of lanthanum oxide to be 2.5 to 3 mol% within the above range.

Next, the replacement amount X of lead oxide for calcium oxide is 0.
It is selected to be 2 or more and less than 0.8. The reason for this range will be clear from FIG.

FIG. 1 shows (Ca O,-, P b O, -6F e,
O,), wa (L aio,), magnet at 1200℃ for 30
It is a graph plotting the relationship between the composition and average magnetic properties when fired for minutes. Maximum energy! 1j(B・t()IaX) has a value approximately three times larger when x = 0.1 than when x = Q, and this is a value equivalent to that of 3a and 3r type ferrite magnets.PbO When the substitution - further increases, (B-H) wax further increases, and when × is 0.2 or more, 0
．． If it is less than 8, it has very good magnetic properties that are equal to or better than 3a and 3r type iron magnets. do. When the amount of PbO substitution increases further to x = 0.8 to 0.9, (B-H) w
On the contrary, ax tends to decrease. This is the reason why @calibration X of PbO was set to 0.2 or more and less than 0.8. In particular, pbo IF*IX is 0.5 or more and 0.7D or less (
7) The composition is 1.5M, which is very high for an isotropic magnet.
(B-H)IaX of G·00 or more has been obtained, which is the most preferable range.

Now, what is noteworthy about the present invention is that the composition as described above has the characteristic that mechanical directionality is easily imparted. As mentioned above, for example, PbO to CaO
If the permutation lx of is 0.5, (B-H)max is 1.5
MG -00 or more, which is a very large value for an isotropic magnet.
Since these samples showed a high value of 50G, these samples were cut into cubes and the magnetic properties were measured in one direction of the press press L1 and in a direction perpendicular thereto. The situation is shown in Figure 2. Figure A is a hysteresis curve in the press pressing direction, and Figure B is a hysteresis curve in a direction perpendicular to the press pressing direction. As can be seen from Figure 2, it clearly has anisotropy, and the isotropic manufacturing method of simply press-forming also creates anisotropy; in other words, these types of magnetic materials are mechanically oriented. It suggests that it is easy.

In other words, the oxide magnet material according to the present invention is extremely remarkable in that an anisotropic magnet can be obtained by simply press-molding it onto the instep using a normal press, without using a troublesome manufacturing method such as magnetic field molding. It has properties. Incidentally, this property is similar to that of CaO explained in connection with the above-mentioned prior art.
This is not observed at all in oxide permanent magnet materials in which M is replaced with O or SrO.

Moreover, this is applicable not only when the oxide magnet material according to the present invention is used as a sintered type magnet, but also when the oxide magnet material powder is mixed with an organic binder such as rubber or plastics and molded. It is also useful when used as a knack magnet. This is because anisotropy is likely to occur during rolling with rollers or pressure molding with a press, and a jaw product with good magnetic properties can be obtained.

Next, examples of the present invention will be described. The raw materials used in the experiment were ca co, pbo, a-F e2
0. , La, O,. The composition is (Ca
b.

P b O,” 6 F e203>f7< La
, o, ), in which X is varied in various ways. The raw material powder was weighed to 300g so as to have the above composition, and these were weighed in a ball mill (
The mixture was mixed for 3 hours using a wet method. After drying the mixed powder, it was molded into a cylindrical sample of 30+vφ×6 cylindrical shape under pressure of 0.5t/cI2. These molded samples were pre-calcined for 1 hour in a temperature range of 900 to 1100° C. in dry oxygen using a Tecorundum tubular furnace. Next, these pre-fired samples were crushed using a stainless steel mortar, passed through a 100 mesh sieve, and further crushed for 30 hours in a stainless steel ball mill (wet method). After drying the slurry calcined powder thus crushed, 5% polyvinyl alcohol solution (concentrate 5%) was added to these powders, mixed, and pressed at a press pressure of about 2 t/d to form a powder with a diameter of 1311 φ and a height of 11 mm. ~13m+a
It was molded into a cylindrical shape. The main firing was performed in dry oxygen at 1175 to 1300°C for 30 minutes using a Tecorundum tubular furnace. An example of the measurement results of the obtained sample is shown in the above-mentioned FIG. 1. As can be seen from the figure, the oxide magnet material according to the present invention is characterized by a large maximum energy product (B-)-1)wax and a high residual magnetic flux density (4πIr>). Although it has not been done, Pb is a catalyst for CaO.
It has also been found that by substituting with O, the pre-calcination temperature can be lowered. In other words, in the case of a Ca-based magnet that is not substituted with PbO, the magnetic properties obtained when pre-sintered at a high temperature (1200°C or higher) are comparable to or higher than those obtained when pre-sintered at a temperature of 900 to 1100°C. It has also become clear that the calcination temperature can be lowered by about 400 to 100°C.

In cholera, (Ca 0o5Pb O,, -6Fe
.

0,), 7(L a, o,) (in terms of mole fractions, Ca O = 6.93-E %, Pb
O-6,93%, Fe20. -'83.14 mol%, La, O, -3 mol%), pre-calcination 100
0°C x 1 hour, main firing at 1225°C x 30 minutes, residual magnetic flux density Br = 2850G, coercive force B)' g = 1
300Q e, maximum energy product (B-H) IIla
It exhibits excellent magnetic properties of x-1.52MG・Oe, and has mechanical anisotropy as shown in Figure 2.The degree of this anisotropy is 1.5M in the press direction.
For G・00 or more, the direction perpendicular to it is 1. OMG
- Approximately Oe.

Further, the oxide permanent magnet material according to the present invention can be given even better magnetic properties by using a manufacturing method such as magnetic field molding that can inherently impart anisotropy.

Since the present invention is a Ca-Pb-La-based oxide permanent magnet material having the composition as described above, it is easy to mechanically provide directionality, and therefore an anisotropic magnet can be produced only by ordinary press molding. It is a material that is useful not only for sintered permanent magnets but also for plastic magnets.
, has magnetic properties comparable to or better than Sr-based magnets, is easy to manufacture, can be made at a low calcination temperature, and has many advantages as magnets for motors, speakers, etc.

[Brief explanation of drawings]

Figure 1 shows (Ca O,xPb Ox・6F e,03
) 97 (L a, o, ) yo magnet is fired at 1200°C for 30 minutes. A graph plotting the relationship between the composition and average magnetic properties. Figure 2A shows the pressing direction of the magnet according to the present invention. FIG. 2B shows the magnetic hysteresis curve in the direction perpendicular to the pressing direction.

Claims (1)

[Claims] 1, (Ca o, -, P b O, c-6F eL
It is represented by the composition formula O,),,,,(shia,O8, and the main component is a chemical composition in which X is 0.2 or more and less than 0.8, and ■ is 2 or more and 5 or less. Ca-pb (
A-based oxide permanent magnet material.