JPS6090868A - Manufacture of high density anisotropic ferrite sheet - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing a high-density ferrite sheet used as a magnetic material for the electronic industry.

Conventional structure and problems Conventionally, Fe20 was used as the raw material powder for making ferrite sheets.
3. MnCOH, Mn3O4, Ni01ZnO metal oxides or metal carbonates were used, or a mixed plate thereof was used. However, for those that do not undergo calcination,
Because the mixture is fired, the shrinkage due to densification is inconsistent.
There are problems such as sheets that are broken, cracked, or warped. In addition, when calcined powder was used, the particle size distribution was poor and the shape was irregular.
It was difficult to create a green sheet with good surface properties because the mixture with the binder was not homogeneous. Furthermore, since the resulting sintered sheet also shrinks unevenly, there were many problems in reproducibility and the like in the production of high-density ferrite sheets.

Furthermore, since the raw material powder does not inherently have shape anisotropy, only isotropic sheets can be produced.

Purpose of the Invention The present invention was invented in order to overcome the above-mentioned problems, and it is possible to stably produce a ferrite sheet having a high density of 98% or more of the theoretical density with good reproducibility. This provides a sheet having crystal anisotropy in its longitudinal direction.

Structure of the Invention The present invention involves mixing a ferrite raw material with a binder to form a nullary with an appropriate viscosity, forming the nullary into a sheet by, for example, a doctor blade method, and firing the green sheet to produce ferrite. When forming the sheet, acicular spinel ferrite raw material powder is used as the ferrite raw material, and each long axis of the acicular raw material powder is oriented substantially in the longitudinal direction of the sheet to create a green sheet, which is then fired. The present invention relates to a method for producing a high-density ferrite sheet, which is characterized by forming a ferrite sheet made of crystal grains with the spinel 110> axis oriented in the longitudinal direction of the sheet.

DESCRIPTION OF EMBODIMENTS FIG. 1 shows the relationship between the crystal axis and shape of the acicular spinel ferrite used in the present invention. As shown in Figure 1, each long axis direction of the acicular powder is the (101) axis (
In other words, in the cubic system, it is equivalent to the <110> axis).

It has the powder shape and crystal axis as above, and has 53 mol% Fe.
2O3, 28 mol% MnO, 19-E-/l/% ZnO
Acicular spine/I/ M n -Z n
- Ferrite powder (long axis approx. 0.5 μm 1 width approx. 0.0.5
.mu.m) with appropriate solvents, surfactants and plasticizers to form a nullary with a viscosity of 2,000 P-10,000 cp. This nullary is processed by the doctor plate method to produce a green sheet having a thickness of 0.1 to 0.5 mm. For the creation of this green sheet, Dr.
Before and/or during the application of the plate, due to the shape anisotropy of the powder, the sheet (Fig. 2(a)
) The acicular mepinel ferrite powder (FIG. 2(b)) is oriented in the longitudinal direction of the ferrite. For this orientation, a magnetic field orientation method may be used, as is used when creating a magnetic tape, and to obtain an even higher orientation, the sheet may be 50 to 10
Warm rolling may be performed at a temperature of 0"C. When warm rolling is performed, the sheet extends in the longitudinal direction, so the tensile stress during the stretching process causes the long axis of the powder to further align with the longitudinal direction of the sheet. This is because the warm rolling increases the density of the sheet molded body, so it also has the effect of increasing the density of the sheet after firing.

The next sheet created in this way was heated from room temperature to 50''C.
The binder was heated to 500°C to 1380″C in air to burn it, and the temperature was further heated in a N2 gas stream from 500°C to 1380″C, held at this temperature for 2 hours, and then N2
Furnace cooling is performed in gas to create a high-density ferrite sheet.

I + Shark, so that everyone can be Kazunari, 1-, needle γ-F
e2 o, , Mn3O4, ZnO as starting materials
A green sheet was created from , fc, x, and rally. Also, the same composition (7) rl -Fe2O3, MnCO3, Z
n0(7) mixture as all starting materials, and this is 8o○~1o
The raw material calcined in air at ○○°C was pulverized in a wet ball mill and then dried to produce a green sheet in the same manner as described above. These sheets were fired under the same firing conditions.

When the densities of the ferrite sheet of the present invention and the ferrite sheet for comparison were measured and calculated from the Archimedes method and shape, it was found that the f110> axis of the present invention was oriented. On the other hand, r-Fe203, Mn304,
In the case of using a ZnO mixed powder, the sintered density was 96%, and the degree of orientation in the longitudinal direction of the sheet was 1/3 to 115 lower than that of the ferrite sheet of the present invention. It happened. Here, the degree of orientation Q (110) is calculated from the reflection intensity in X-ray diffraction using the following formula. It is something.

When shown using the above orientation degree Q (110), the high density anisotropic ferrite sheet of the present invention had Q (4:co) of about 170 to 90%. On the other hand, the conventional α-Fe203
, MnCO3, and ZnO (D), the sintered density was 95%, and no crystal anisotropy in the longitudinal direction of the sheet was found.

In addition to the effects of the invention, as described in the examples, the powder using the acicular spinel ferrite powder of the present invention as a starting material has a 98%
The above-mentioned high-density ferrite can be obtained, and the spinel axis is oriented substantially in the longitudinal direction of the can sheet, making it possible to produce fcs-oriented ferrite.

[Brief explanation of drawings]

FIG. 1 shows the shape and crystal axis orientation of the acicular spinel ferrite powder used in the present invention, and FIG. 2 shows the ferrite sheet of the present invention. (a) Sheet (b) Acicular spinel ferrite powder Patent applicant Matsushita Electric Industrial Co., Ltd. Agent Kenbu Niimi (1 other person) Figure Il1

Claims (1)

[Claims] By mixing the ferrite raw material with a binder, it is made into a slurry with an appropriate viscosity, and when this slurry is formed into a sheet and the green 2 sheet is fired to form a ferrite sheet, needle-shaped nuts are used as the ferrite raw material. Using pinel ferrite raw material powder, a green sheet is created in which the long axes of the acicular raw material powder are substantially oriented in the longitudinal direction of the sheet, and then by firing, the nupinel ferrite 110 is oriented in the longitudinal direction of the sheet. 〉A method for producing a high-density ferrite sheet O, which is characterized by forming a ferrite sheet consisting of crystal grains oriented in the axial direction.