JPH0455362A - Oxide magnetic material - Google Patents

Abstract

PURPOSE:To form an oxide magnetic material having very high initial magnetic transmissivity and small loss by adding a specified amt. of Ta2O5 and/or TiO2 to Mn-Zn ferrite. CONSTITUTION:Ta2O5 and/or TiO2 is incorporated into Mn-Zn ferrite based on Fe2O3, MnO and ZnO by >0-0.3 wt.% to obtain an oxide magnetic material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a magnetic permeability oxide material of Mn--Zn ferrite.

[Prior art and problems to be solved by the invention] Conventional high permeability oxide magnetic materials are F e 20 i +MnO
, ZnO are mixed, prefired, and finely pulverized, the resulting powder is molded, and then fired under predetermined conditions.

1 In this manufacturing method, a method is also used in which a small amount of 5in2CaO is added to control the grain size and other magnetic properties, but this method does not improve the structure of the sintered body, which is essential for obtaining high initial magnetic permeability. Equalization of the crystal grain size and reduction of the bores existing within the crystal grains and at the grain boundaries were insufficient, and an initial magnetic permeability of about 1 oooo could only be obtained at most.

Therefore, two technical problems of the present invention are to be solved in view of the above-mentioned drawbacks.

The object of the present invention is to provide a high permeability oxide magnetic material having extremely high initial permeability and low loss.

[Means for solving al] According to the present invention, in the Mn-Zn-based ferrite whose main components are Fe203, MnO, and ZnO.

0.3 vt of one or both of Ta205 and TiO2
% or less (not including 0) is obtained.

That is, the inventors of the present invention have conducted various studies regarding the above-mentioned problems and have developed Ta205. One or two types of Ti0z
It has been found that by containing ~0.8 wt% (excluding 0) in a sintered body, it is possible to obtain an extremely high initial magnetic permeability and low loss Mn-Zn-based ferrite. It is something. In order to achieve high initial permeability and low loss.

The main component is Fe2o3. It is important to control the composition of MnO and ZnO with extremely high precision, and at the same time, it is important to maintain the sharpness of the crystal grain size distribution mentioned above, reduce the bores existing within the crystal grains and at the grain boundaries, and further improve the Improving compositional uniformity is essential.

However, when the sintering temperature is raised to improve the compositional uniformity within the crystal grains, abnormal grain growth occurs in the sintered body, resulting in an extremely wide grain size distribution and a high initial magnetic permeability. Not only will there be no losses, but the losses will be large.

In the present invention, as a means to overcome the above-mentioned drawbacks,
Ta20q, one or two of Tio□ from 0 to 0.3
It is proposed to include it in the fired body by adding vt% (not including 0). Namely.

According to the present invention, by adding these oxides, it is possible to obtain an oxide magnetic material having extremely high initial magnetic permeability and low loss.

This is because: 1 When these oxides are added, control of crystal grain growth becomes extremely easy, and abnormal grain growth does not occur and the crystal grain size distribution is sharp. This seems to have been achieved by reducing the existing bore.

In addition, Ta2O precipitates at grain boundaries and forms a grain boundary phase, thereby reducing the frequency dependence of magnetic permeability, which has the advantage of being able to have high magnetic permeability even at relatively high frequencies.

In the present invention, the addition amount of one or both of Ta, O, and Tie is 0.3 vt% or less, which is 0°8 w.
If the amount added exceeds L%, abnormal grain growth will occur, lowering the magnetic permeability and increasing the loss coefficient, so 0.3
It is necessary to keep it below wt%.

[Example-1] Next, an embodiment of the present invention will be described with reference to the drawings.

First, iron oxide and zinc oxide with a purity of 99.5vt% or higher.

and pure jjt92. 52Fe203 -25Mn0-23ZnO (sol
The main component raw materials were weighed and mixed in a ball mill so as to give a total of 10%), and the mixed powder was further calcined at about 1000°C (to be used as a working material).O-04vt% of Ta2O was added to this working material.

This powder was further mixed and pulverized in a ball mill.

The obtained powder was granulated and then compacted at 2 tan/c- to obtain a green compact. This green compact was main fired at 1200 to 1450°C in a mixed gas flow of nitrogen and oxygen with an oxygen partial pressure of 0 to 1.0%.

In addition, as a comparison material, a sintered body was obtained by using a powder obtained by grinding in a ball mill without adding any additives to the powder of the work material in the same process as above.

Figure 1 shows the characteristics of the most excellent initial permeability and loss coefficient among the sintered bodies obtained when T a 20 s * was added and the firing conditions were varied, compared with the comparison material (conventional product). Shown. (g temperature 1 frequency 10 kHz) Ta2Q according to the present invention
It can be seen that the sample to which 0.3 vL% or less (not including 0) of , was added exhibits superior properties to the comparative material, which is a conventional product.

[Example-2] In the same manner as in Example-1, Tie2 was adjusted to 0 to 0.4 vL.
% added sample was fired, and the amount of TiO□ added and μ0゜tan
The relationship between δ/μ and hlo was investigated. Figure 2 shows the results. It can be seen that in the range where the amount of Tie added is 0.3 vt% or less (not including 0), characteristics superior to conventional products are exhibited.

[Example-3] The powder of the work material obtained in Example-1 was added as shown in Table 1.
Ta205. A fired body was obtained in the same manner as in Example-1 except that Ti02 was added in combination. Table 2 shows Ta2O, TiO2
A comparison of the characteristics of a fired body obtained by adding a compound of and a conventional product is shown. Combined addition of Ta2O, TiO2 (0.3vt%
(below), it can be seen that the product exhibits superior properties compared to conventional products.

Table below with margin Measurement temperature: Room temperature Δ-j Constant frequency: 10 ktlz [Example-4] T a obtained in Example-1 20. , 0.25wt
The frequency characteristics of μ0 were measured for the fired body (product of the present invention) to which % was added and the conventional product. FIG. 3 shows the frequency dependence of μ0 for the product of the present invention and the conventional product. It can be seen that the product of the present invention not only exhibits a higher μ0 than the conventional product, but also has good frequency dependence and can be used at high frequencies.

[Effects] As described in the above examples (in a method for manufacturing Mn-Zn-based high permeability oxide magnetic materials by a normal powder metallurgy method, Ta, 05.TjO, powder is lol
By adding L% (not including 0), it is possible to obtain a high permeability oxide magnetic material with significantly high initial permeability and low loss.

Furthermore, the addition of Ta and O can also improve the frequency dependence of the initial magnetic permeability, which is extremely effective in practice.

This is presumed to be because the addition of T i 02 and Ta205 makes it easier to control grain growth during firing, resulting in a structure with high initial permeability and low loss.

[Brief explanation of drawings]

Figure 1 shows the amount of Ta205 added and μo in Example-1.
, tan δ/μ, hlO(at room temperature - 10kllz). Figure 2 shows the relationship between the amount of T i O2 added and μ in Example-2.
It shows the relationship between o, tan δ, and hlO (at room temperature - 10 kHz). Figure 3 shows the present invention product Ta2O, 0, in Example-4.
2vt% addition) and the frequency dependence of μ0 of the conventional product. Figure 1

Claims (1)

[Claims] 1) M whose main components are Fe_2O_3, MnO, and ZnO
In n-Zn ferrite, Ta_2O_5, Ti
An oxide magnetic material characterized by containing 0.3 wl% or less (excluding 0) of one or two types of O_2.