JPS6014489B2 - Manufacturing method of oxide permanent magnet - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing an oxide permanent magnet.

Ferrite magnets have low raw material and manufacturing costs, and their production volume is increasing rapidly, and their uses are becoming more diverse.There is also a demand for magnets with higher magnetic properties in terms of miniaturization and weight reduction.

Conventionally, it has been known to use a mixture of two or more of bismuth oxide Bi203, terra sand Na2B407 series, terra acid oxide 2B03, terra sand and silica, etc. as additives to improve the magnetic properties of oxide permanent magnets.

Although these shelving substances are very effective as additives, they are extremely easily soluble in water and cannot be used in production methods that involve dehydration during or before pressing oxide permanent magnets.
During the dehydration process during molding, most of it flows out with water, and the amount of shelving remaining in the molded product is inconsistent.
It has drawbacks such as causing variations in magnetic properties.

Moreover, it is technically extremely difficult to accurately control the outflow of the water-dropping shelving material and to maintain a constant amount of the shelving material remaining in the molded body. For example, in wet pressing, which dehydrates water during pressing, this method is widely used because the particles are oriented by the magnetic field and a high-performance oxide permanent magnet can be obtained, but conventional methods have the disadvantages mentioned above. The disadvantage is that relatively expensive shelving materials are leaked outside the facility. In view of this, the present invention has developed MB204 (
However, by adding a shelf compound represented by M (Ca, Sr, Pb, Mn) and bismuth oxide (Bi203), we propose this type of oxide permanent magnet with small variations in magnetic properties and high properties. The main purpose is to

In the present invention, in the method for producing an oxide permanent magnet, one or more of water-insoluble or refractory willow oxygen compounds MB204 (where M is Ca, Sr, step, Pb, Mn) and bismuth oxide are used. Bi203 is used as an additive.

If the amount added is too small, the effect will not be fully exhibited, while if it is too large, it will act as an impurity, leading to a decrease in magnetic properties and being economically disadvantageous. Therefore, the total amount of the above-mentioned additives added is suitably in the range of 0.01 to 7% by weight, preferably 0.05 to 4% by weight. In addition, the ratio of shelving compounds to bismuth oxide is such that if there is too little bismuth oxide, the effect will not be fully exhibited, and on the other hand, if there is too much, BHc
The effect of the addition is lost. Therefore, if the amount of shelf elements in a shelf element compound is 1, the amount of bismuth oxide is 0.
A range of 1 to 4 times by weight is suitable, preferably a range of 0.5 to 2 times by weight. In addition, when adding additives, weigh the main raw materials so that the molar ratio of Fe203/MO=5.0 to 6.0 (however, M=Ba, Sr, Pb),
(However, one or more of M=Pb, Ba, Mh, Ca, Sr) and bismuth oxide Bi203 are added and mixed thoroughly, then suspended at 1000-1400 o'clock, and then subjected to wet pulverization. Molded in a magnetic field, 1000-1400℃
It is effective when firing in In addition, the molar ratio of the main raw materials is Fe203/MO: 5.0 to 6.0 (however, M: Ba,
Sr, Pb), and after thorough mixing, 10
M&04 (however, M
; Pb, Ba, Mn, Ca, Sr) and bismuth oxide Bi203 are added, followed by wet pulverization, molding in a magnetic field, and firing at 1000 to 1400 o○. obtain. Each embodiment of the present invention will be described in detail below.

Example 1 Commercially available industrial barium carbonate ball C03 powder with a purity of 97% or more and commercially available industrial iron oxide Fe203 powder with a purity of 99% or more were used as main raw materials such that the molar ratio of Fe203/BaC03 was 5.6. Weigh it and add shelf acid PbB204 to it.
and bismuth oxide Bi2Q in the amounts shown in Table 1 were thoroughly mixed in a Lycay machine, and then fired at 122,000 in a muffle furnace.

1.5 kg of barium ferrite obtained was added with 1.5 kg of water and finely pulverized for 3 hours using a ball mill until the average particle size was 1.5 kg.
Barium ferrite powder of 0.0 mm was obtained. This powder was wet-molded in a magnetic field to obtain a barium ferrite magnet. The magnetic properties of bismuth oxide Bi2030 with no additives
．． Table 1 shows a comparison between when 3 and 0.5% by weight were added alone. In addition, when the residual amount of lead oxide PbQ04 in the manufactured magnet was measured by atomic absorption spectrometry, it was found that 98% of the added amount
．． It was confirmed that 5% by weight remained.

Table 1 Example 2 Manganese oxide M 204 and bismuth oxide B as additives
Table 2 shows the magnetic properties obtained in the same manner as in Example 1 except that i203 was added.

Table 2 Example 3 Barium shelf acid Ba&04 and bismuth oxide B as additives
Table 3 shows the magnetic properties obtained in the same manner as in Example 1 except that i203 was added.

Table 3 Example 4 Commercially available industrial strontium carbonate S with a purity of 97% or more and 03 powder and commercially available industrial iron oxide Fe with a purity of 99% or more
203 powder as the main raw material was weighed so that the molar ratio of Fe203/S to 03 was 5.8, thoroughly mixed in a Raikai machine, and then calcined for 2 hours at 122 P0 using a Matsufuru furnace.

Shelf acid lead Pb is added to the obtained strontium ferrite lk9.
B204 and bismuth oxide Bi203 were added to the mixture, mixed with 1.5 hours of water, and pulverized in a ball mill for 4 hours to obtain an average particle size of 1.5 mm. A solid strontium ferrite powder was obtained. This was subjected to green molding in a magnetic field, and the obtained sample was
Firing was performed at 00° C. for 2 hours to obtain a strontium ferato magnet. Its magnetic properties are shown in Table 4. Table 4 Example 5 Manganese oxide M-Kyo 204 and bismuth oxide B as additives
Table 5 shows the magnetic properties when the same method as in Example 4 was used except that i203 was added.

Table 5 Example 6 Barium oxide Ba&04 and bismuth oxide B as additives
Table 6 shows the magnetic properties obtained in the same manner as in Example 4 except that i203 was added.

Table 6 Example 7 Using commercially available industrial barium carbonate C03 powder with a purity of 97% or higher and commercially available industrial iron oxide Fe203 powder with a purity of 99% or higher as the main raw materials, the molar ratio of Fe203/BaC03 was 5.
．． Table 7 shows the magnetic properties when the sample was weighed as shown in Table 7 and measured in the same manner as in Example 4.

The additives are ■ shelf acid associated PbB204, ■ shelf acid manganese M
nB204, ■ Barium siderate B204, ■ Strontium siderate SrB204, ■ Calcium siderate CaB204
The test was conducted on a combination of and bismuth oxide Bi203. Table 7 As described above, according to the present invention, in the method of manufacturing an oxide permanent magnet, MB204 (where M=Pb, stages, Mn,
Since one or more of Sr, Ca) and bismuth oxide are added before the calcination process or after the calcination process, the magnetic flux density Br is lower than that of a permanent magnet without the above additives.
, coercive force unevenness c, and maximum energy product (BH) max.

In addition, the additive M old 204 (
However, when the amount of (M=Sr, Pb, mother, Ca, Mn) was measured by a daughter absorption spectrometry method, it was confirmed that more than 9% by weight of the added amount remained.

Claims (1)

[Claims] 1 BaO, SrO, PbO or one or more compounds that become oxides of these when heated and Fe_2O_3
Or Mo.6Fe_2O_3 obtained by heating using Fe_2O_3 as a raw material (where M=Ba, Sr, Pb)
In the method for manufacturing oxide permanent magnets having the basic formula:
MB_2O_4 (However, M=Pb, Ba, Mn, Sr, C
A method for producing an oxide permanent magnet, characterized in that one or more of a) and bismuth oxide are added before or after the calcination step.