JPH06263447A - High permeability mn-zn ferrite - Google Patents

Abstract

PURPOSE:To obtain a Mn-Zn based ferrite high in permeability and excellent in temp. characteristics by restricting the composition of the Mn-Zn based ferrite and specifying initial permeability and the rate of change thereof. CONSTITUTION:The Mn-Zn based-ferrite contains 52.5-53.0mol.% Fe2O3, 22-25mol.% ZnO and balance MnO and is >=8000 in initial permeability mu at -200-100 deg.C and <=70% in rate of change. In the ferrite, it is the reason why restricting the component that the initial permeability nearly at room temp. can not attain >=8000 since the secondary peak (Ts) becomes minus side due to the temp. characteristics of the initial permeability when Fe2O3 is >=53mol.% and when Fe2O3 is <=52.5mol.%, the secondary peak is in high temp. side and the initial permeability mu in the minus side can not attain >=8000.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to Mn--Zn type ferrite having high magnetic permeability and excellent temperature characteristics.

[0002]

2. Description of the Related Art Mn--Zn type ferrite having a high magnetic permeability is mainly composed of Fe ₂ O ₃ , ZnO and MnO, and various additives (Ca, Si,
V, Bi) was added to the material. This Mn-Zn
The system ferrite is used as a magnetic core of a transformer, a noise filter, etc., and miniaturization of components is being promoted by utilizing its high magnetic permeability characteristic.

[0003]

[Problems to be Solved by the Invention] For example, ISDN S /
In the pulse transformer used for the T point interface,
Securing 20 mH of inductance on the line side is an essential condition for satisfying the impedance mask defined in CCITT I.430. Here, considering the equipment used, public telephones and line termination devices (D
(SU) is considered to be installed outdoors or under the eaves, and its environmental condition is currently guaranteed at −10 to 70 ° C. in the LSI, and similarly, temperature guarantee is also required in the pulse transformer. However, in the case of the conventional Mn-Zn-based high magnetic permeability ferrite, the initial magnetic permeability remarkably decreases on the low temperature side (20 ° C. or less), and if designed under this environmental condition, the impedance standard on the low temperature side is satisfied. There has been a problem that the number of turns is increased and a material having a magnetic permeability higher than necessary is used, which is very inefficient. In view of the above, the present invention provides M having high magnetic permeability and excellent temperature characteristics.
The purpose is to obtain an n-Zn ferrite.

[0004]

According to the present invention, in Mn-Zn type ferrite, Fe ₂ O ₃ is 52.5 to 53.0 mol,% ZnO is 22 to 25 mol%, and the balance is MnO. A high magnetic permeability Mn—Zn-based ferrite having a μi of 8000 or more in a temperature range of −20 to 100 ° C. and a change rate of 70% or less. According to the present invention, in the above Mn—Zn-based ferrite, the secondary magnetic permeability (Ts) of μi is −25 in the temperature characteristic of the initial permeability μi.
High magnetic permeability Mn-Z characterized by being in the range of -10 ° C
It is an n-type ferrite. According to the present invention, in the above Mn—Zn ferrite, the initial magnetic permeability μi is at a temperature of −20 to 100 ° C.
Is 8000 or more and the rate of change thereof is within 40%. The present invention provides the above Mn—Zn ferrite,
As auxiliary components, CaO is 0.05 wt% or less (however, 0 wt% is not included), SiO ₂ is 0.01 wt% or less (however, 0 wt% is not included), and V ₂ O ₅ is 0.05 wt%. Below (not including 0% by weight), 0.1% by weight of Bi ₂ O ₃
Mn-Zn containing the following (excluding 0% by weight)
-Based ferrite with an initial permeability μi of -20 ° C to 1
8000 or more in the range of 00 ° C, and the rate of change is 70
% Mn-Zn-based ferrite having a high magnetic permeability. In the present invention, in the above Mn—Zn-based ferrite, CaO is 0.01 to 0.02 among the accessory components.
The high permeability Mn—Zn-based ferrite is characterized in that it has a weight percentage of 8000 or more at a frequency of 100 kHz and 4000 or more at a frequency of 300 kHz. In the present invention, the main component is limited because Fe ₂
When O ₃ is 53 mol% or more, the secondary magnetic permeability (Ts) becomes negative on the temperature characteristic of the initial magnetic permeability μi, and the initial magnetic permeability μi at room temperature cannot be 8,000 or more.
When Fe ₂ O ₃ is 52.5 mol% or less, the secondary peak is on the high temperature side and μi on the negative side is 8000.
Because you cannot get the above.

[0005]

【Example】

Example 1 Fe ₂ O ₃ , MnO, and ZnO were prepared as raw materials having the main component compositions shown in Table 1. The raw materials were calcined at 850 ° C. for 2 hours and then crushed by a ball mill for 8 hours, and compressed into a ring shape. It was molded and fired at 1360 ° C. for 5 hours at an oxygen concentration of 5%. Table 1
The frequency of samples with different principal component composition is 10 kHz.
The initial permeability μi at each temperature in z and the change rate of μi in the temperature range of −20 to 100 ° C. (Δμi / μi)
Indicates. Further, the secondary peak (Ts) of the temperature characteristics of tan δ / μi and μi at 20 ° C. is also shown. In Table 1, those within the range of the present invention are examples, and those outside the range are comparative examples. In addition, the sample No. 2 (Example 2) and sample No. 13 (Comparative Example 5) with initial magnetic permeability μ
A graph of the change of i with temperature is shown in FIG. This Figure 1
As can be seen from the above, it can be seen that the examples of the present invention are materials having a small change in initial magnetic permeability with respect to temperature.

[0006]

[Table 1]

Example 2 Fe ₂ O ₃ 52.6 mol%, MnO 22.9 mol%,
ZnO 24.5 mol% as a main component, CaO,
A raw material containing SiO ₂ , V ₂ O ₅ , and Bi ₂ O ₃ in the amounts shown in Table 2 was prepared, calcined at 850 ° C. for 2 hours, then crushed by a ball mill for 8 hours, and compression-molded into a ring shape. Thirteen
It was baked at 60 ° C. for 5 hours at an oxygen concentration of 5%. As with Example 1, Table 2 shows μi and the rate of change of μi under each temperature at a frequency of 100 kHz. Also,
Μi at a frequency of 300 kHz is also shown.

[0008]

[Table 2]

[0009]

According to the present invention, it has a high magnetic permeability from the low temperature side (-20 ° C) to the high temperature side (100 ° C), and
Due to the temperature difference, it is possible to obtain Mn—Zn based ferrite having a small change rate of magnetic permeability.

[Brief description of drawings]

FIG. 1 is an initial magnetic permeability μi of an example according to the present invention and a comparative example.
Is the temperature characteristic of.

Claims (5)

[Claims] 1. A Mn--Zn system ferrite comprising Fe
₂ O ₃ is 52.5 to 53.0 mol%, ZnO is 22 to 25
Mol%, the balance is MnO, and the initial magnetic permeability μi is temperature -20 to
8000 or more in the range of 100 ° C, and the rate of change is 7
A high magnetic permeability Mn-Zn-based ferrite characterized by being within 0%. 2. The Mn—Zn-based ferrite according to claim 1, characterized in that a secondary peak (Ts) of μi is in a range of −25 to 10 ° C. in a temperature characteristic of initial permeability μi. Permeability Mn-Zn ferrite. 3. In the Mn—Zn system ferrite, Fe
₂ O ₃ is 52.5 to 53.0 mol%, ZnO is 22 to 25
High magnetic permeability Mn-Z, characterized by being mol% and residual MnO, having an initial magnetic permeability μi of 8000 or more in the range of −20 ° C. to 100 ° C. and having a change rate of 40% or less.
n-type ferrite. 4. In the Mn--Zn ferrite, Fe
₂ O ₃ is 52.5 to 53.0 mol%, ZnO is 22 to 25
Mol%, residual MnO, 0.0% CaO as an accessory component
5% by weight or less (not including 0% by weight), 0.01% by weight or less of SiO ₂ (not including 0% by weight), V ₂
O ₅ is contained in an amount of 0.05% by weight or less (however, 0% by weight is not included), Bi ₂ O ₃ is 0.1% by weight or less (however, 0% by weight is not included), and the initial permeability μi is temperature- 20-100
A high-permeability Mn-Zn-based ferrite having a temperature change rate of 8000 or more and a change rate of 70% or less. 5. The Mn—Zn-based ferrite according to claim 4, wherein CaO is 0.01 to 0.01% among the sub-components.
0.02% by weight, initial permeability μi is frequency 100k
8000 or more in Hz, 4000 at 300 kHz
A high magnetic permeability Mn—Zn-based ferrite characterized by the above.