JPH0784340B2 - Ni-Cu-Zn-based oxide magnetic material and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a Ni—Cu—Zn oxide magnetic material and a method for producing the same, and particularly to a Ni—Cu having a structure for relieving external stress.
The present invention relates to a Cu-Zn oxide magnetic material and a method for manufacturing the same.

[Conventional technology]

Conventionally, this type of Ni-Cu-Zn-based oxide magnetic material has been used for rotary transformer cores and the like, so that when it is processed into a product shape, grinding and handling have been performed.

[Problems to be solved by the invention]

However, the conventional Ni-Cu-Zn oxide magnetic material is
Since it is a brittle material itself, polishing defects such as polishing chips occur during grinding and handling.
There were drawbacks such as deterioration of product quality and yield.

Therefore, in view of the above drawbacks, an object of the present invention is to provide Ni-Cu- which has excellent material strength and reduces polishing defects such as polishing chips.
A Zn-based oxide magnetic material and a method for producing the same are provided.

[Means for solving problems]

According to the present invention, 30.0-35.0 mol% zinc monoxide ZnO, 14.0
〜 18.0mol% nickel monoxide NiO, 3.0〜6.0mol% copper monoxide CuO, and the balance of ferric oxide Fe ₂ O ₃ between the grain boundaries of the crystal, 0.03wt% or less of silicon dioxide SiO ₂ , 0.10 Wt% or less manganese monoxide MnO and 0.07 wt% or less bismuth trioxide BiO
Ni- with excellent material strength characterized by interposing a stress relaxation layer consisting of at least one selected from ₃
A Cu-Zn oxide magnetic material is obtained.

Further, according to the present invention, 30.0 to 35.0 mol% of zinc monoxide Zn
O, 14.0 to 18.0 mol% Nickel monoxide NiO, 3.0 to 6.0 mol%
Of CuO and the balance of ferric oxide Fe ₂ O ₃ with 0.03wt% or less of silicon dioxide SiO ₂ , 0.10wt% or less of manganese monoxide MnO and 0.07wt% or less of bismuth trioxide BiO.
_A method for producing a Ni-Cu-Zn-based oxide magnetic material, characterized by comprising adding at least one subcomponent selected from _{3 and then} sintering.

The sintering temperature during the sintering in the present invention is 1130 to 1170.
C. is preferred.

That is, the present invention is based on the main component of Ni-Cu-Zn ferrite.
A secondary component was added so as not to reduce the material strength. Silicon dioxide (SiO ₂ ), manganese monoxide (MnO), and bismuth dioxide (Bi ₂ O ₃ ) were used as the secondary components, and 1130-1
The feature is that sintering is performed in the range of 170 ° C.

Thus, according to the present invention, the auxiliary component that is an additive is
It exists as a stress relaxation layer interposed between the grain boundaries of the crystal composed of the main component. Therefore, such a stress relaxation layer exhibits an effect such as a so-called cushion for relaxing the stress against the external stress, and as a result, the material strength can be improved.

〔Example〕

 Next, an embodiment of the present invention will be described with reference to the drawings.

-Example 1-First, 30.0 to 35.0 mol% ZnO, 14.0 to 18.0 mol% NiO, 3.0
Bi ₂ O ₃ was added as 0.0%, 0.05%, and 0.10% by weight to the main component of the calcined powder containing CuO of 6.0 mol% and the balance of Fe ₂ O ₃ , and the mixture was crushed by a ball mill and mixed. It was made into powder with a spray dryer, and this powder was pressed with a mold having a length of 60 mm x a width of 17 mm x a thickness of 5 mm, and then sintered at 1170 ° C for 2 hours.
The material strengths are shown by the fracture toughness value (hereinafter abbreviated as K _1C ) in FIG. ₁ and the transverse rupture force (hereinafter abbreviated as F) in FIG.

As a result, the maximum K _{1 C} was 0.05 wt% among the three levels of Bi ₂ O ₃ . F had the maximum content of Bi ₂ O ₃ of 0.05 wt%. In addition, Bi ₂ O ₃
The material obtained by sintering the non-added one is at the conventional level.
Therefore, K _{1 C} is 64% higher and F is 14% higher than the conventional level. This is because the addition of 0.05% Bi ₂ O ₃
This is because the breakage occurs at the grain boundary portion of the crystal. Also, Bi ₂
When O ₃ was added at 0.10 wt%, the amount of addition was large, so that crystal swelling occurred and K _{1 C} and F both decreased.

- In a similar manner to Example 2 Example 1, 0.03 a range of the addition amount of Bi ₂ O _3,
The experiment was conducted by changing to 0.05, 0.0 wt%. As a result, as shown in FIG. 3 and FIG. 4, K _1C has high toughness within this range. Although F decreased somewhat, it was at the conventional level or higher.

- Example 3 Next, in the same manner as in Example 1, high K _1C, 0.05 w indicating the F
For t% Bi ₂ O ₃ , the sintering conditions were 1220,1200,1150,1100.
Experiments were carried out with 4 kinds of temperature, held for 2 hours. as a result,
As shown in Fig. 5 and Fig. 6, K _1C showed crystal swelling at 1220 ° C, and at 1100 ° C, intergranular fracture occurred and the respective values decreased. F is an example obtained by changing the sintering conditions.
Compared with 1,2, improved values were obtained at 1200 ℃.

-Example 4-Next, in the same manner as in the example, an experiment was carried out in the range of 1170, 1150, and 1130 ° C with Bi ₂ O _{3 at} a level of 0.05 wt%.
As a result, as shown in Fig. 7 and Fig. 8, K _1C at this temperature is 2.0 [GN / m ^3/2 ] or more, and F is 600 [kg / c
m ² ] or more was obtained.

As can be seen from the above results, the main components of the Ni-Cu-Zn system are
It was confirmed that improvement of K _{1 C} and F could be obtained by adding BiO _{3 of} 0.07% or less and sintering in the range of 1300-1170 ℃.

In this example, only BiO ₃ was added as a subcomponent, but it is clear that the same effect can be obtained by using SiO ₂ and MnO as other subcomponents.

The test method used in this example will be described below.

Several methods have been proposed for measuring fracture toughness K _1C (which means the critical value at which fracture starts to develop rapidly). Here, Indentation Mi
crofracture: IM method (micro-indenter indentation fracture method) (Ceramics 20 (1985) No. 1 “Special Feature / Determination of Mechanical Properties of Ceramics” (P12-18, Koichi Niihara)).

First, one surface of the sample is mirror-polished. Next, a Vickers hardness tester is used to make Vickers indentations on the mirror surface. As a result, in the case of a brittle material, as shown in FIG. 9, four crackers are generated on the extension of the indentation diagonal line. Measure the length of 2a and 2c in the figure and enter the load: P (kg). In the C measurement, the X- and Y-ray measurement measures the length from the center of each of the four cracks, and _K1C is calculated by the following equations (1) and (2).

^{_{(K 1C / H · a 1/2}} ) = 0.203 (C / a) -3/2 (1) H = 0.464 · P · a -2 × 9.8 (2) K 1C: Fracture Toughness [N / m ^1.5 ] H: Vickers hardness [N / m ² ] a: Vickers indentation length 1/2 [m] C: Crack length 1/2 [m] P: Load [kg] In this example, 5 points were measured from 2 samples per level.

Next, regarding the measurement of transverse rupture strength, as shown in Fig. 10, 3
Using a point bending test, the setting condition is that the load speed is 0.01 mm.
/ min, the distance between the fulcrums is set to 30 mm (ceramic JIS standard span), and F is calculated by the following equation (3).

P: Load (kg) l: Distance between fulcrums (cm) W: Width of sample piece (cm) t: Thickness of sample piece (cm) F: Bending strength (kg / cm ² ) In this example, The number of measurements was 5 points from 2 samples per level.

On the other hand, the fracture state judged by the crystal of the sample and the IM method (K _1C ) and the three-point bending test (F) was observed by an electron microscope (SEM).
Observed) and distinguished as follows.
It is shown in FIG.

As described above, according to the present invention, the main component of the Ni-Cu-Zn system contains 0.07 wt% or less of BiO ₃ , 0.03 wt% or less of SiO ₂ , 0.10.
By adding at least one subcomponent selected from wt% or less of MnO, and preferably sintering at 1130 to 1170 ℃, the subcomponent is formed between the grain boundaries of the Ni-Cu-Zn ferrite crystal. A magnetic material having a structure in which a stress relaxation layer is interposed can be obtained. Therefore, since the stress relaxation layer can relax the stress from the outside, it is possible to provide a Ni-Cu-Zn-based oxide magnetic material having high material strength, high toughness, and high strength.

[Brief description of drawings]

1 and 3 show the amount of Bi ₂ O ₃ and K according to the embodiment of the present invention.
Correlation diagram with _1C , FIGS. 2 and 4 are correlation diagrams with Bi ₂ O ₃ and F according to the embodiment of the present invention, and FIGS. 5 and 7 are sintering temperatures according to the embodiment of the present invention. And K _1C correlation diagram, FIGS. 6 and 8 are correlation diagrams between sintering temperature and F according to the embodiment of the present invention,
FIG. 9 is a conceptual diagram of Vickers indentation, and FIG. 10 is a conceptual diagram of a three-point bending test.

Claims (3)

[Claims] 1. Zinc monoxide, 30.0-35.0 mol% ZnO, 14.0-1
0.03wt% or less of silicon dioxide SiO ₂ , 0.10wt between the grain boundaries of the crystal consisting of 8.0mol% nickel monoxide NiO, 3.0 to 6.0mol% copper monoxide CuO and the balance ferric oxide Fe ₂ O ₃ % Manganese monoxide MnO and 0.07 wt% bismuth trioxide BiO
Ni- with excellent material strength characterized by interposing a stress relaxation layer consisting of at least one selected from ₃
Cu-Zn oxide magnetic material. 2. Zinc monoxide, 30.0-35.0 mol% ZnO, 14.0-1
0.03 wt% of the main component containing 8.0 mol% nickel monoxide NiO, 3.0 to 6.0 mol% copper monoxide CuO and the balance ferric oxide Fe ₂ O ₃
% Silicon dioxide SiO ₂ , 0.10 wt% or less manganese monoxide MnO, and 0.07 wt% or less bismuth trioxide BiO ₃ at least one sub-component selected from the group consisting of Ni and sintering. A method for producing a Cu-Zn-based oxide magnetic material. 3. The method for producing a Ni—Cu—Zn oxide magnetic material according to claim 2, wherein the sintering temperature at the time of the sintering is 1130 to 1170 ° C. −Cu−Zn
Of producing a magnetic oxide magnetic material.