JPS6016863A - Manganese-zinc ferrite magnetic recording magnetic material and manufacture - 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 The present invention relates to a novel manganese-zinc ferrite suitable as a magnetic material for magnetic recording, particularly as a magnetic hesodo core material.

In recent years, in the field of magnetic recording technology, as the amount of information has increased, conventional recording densities have become insufficient, and higher density recording has become necessary. However, it has become necessary to develop magnetic head core materials with higher effective magnetic permeability at higher frequencies.

It is known that manganese-zinc ferrite is used as a core material for magnetic heads. It has the advantage of showing However, this material has a low effective magnetic permeability in the frequency band used by floppy heads, making it difficult to obtain sufficient reproduction sensitivity and s/+q ratio, which may cause malfunctions, so it cannot be used as a magnetic head core material for electronic computers. It could not be used as. Also, this manganese-zinc ferrite for floppies is known, but
Because the effective magnetic permeability and loss coefficient in the 2.0 MH2 frequency range limit the ability of the first-order amplifier, it is not suitable as a core material for magnetic heads used in large computer disks such as Winchester. Appropriate.

It has also been proposed to improve the drawbacks of manganese-zinc ferrite by adding niobium oxide. This one is 0.5 to 2. In the QMHz frequency range, it shows a large effective magnetic permeability ↑ and a small loss coefficient, but it is 5.0 to 7.
In the high frequency range of 0MH2, sufficiently satisfactory results cannot be obtained.

In view of these circumstances, the present inventors have decided to develop a manganese-zinc-based ferrite magnetic material that exhibits a large effective permeability and an appropriate loss coefficient in the high frequency range and can fully meet the demands of high-density recording. As a result of extensive research,
It was discovered that the objective could be achieved by adding a predetermined amount of niobium oxide together with predetermined amounts of vanadium oxide and calcium oxide and sintering it to a high density, and based on this knowledge, the present invention was accomplished.

That is, the present invention uses Fe2O355.0-57.0 mol%, zno 5.0-25.0 mol% and MnO4
Manganese-zinc ferrite with a basic composition of 0.0 to 18゜0 mol%, and niobium oxide of 0.005 to 18゜0 mol%.
The present invention provides a magnetic material for magnetic recording containing 0.1% by weight of vanadium oxide, 0.005 to 0.05% by weight of vanadium oxide, and 0.01 to 0.30% by weight of calcium oxide.

The magnetic material of the present invention is characterized in that it exhibits a very large effective magnetic permeability in a high frequency region of 0.5 to 1.0 MHz. For example, this one is 3.5MHz
1500 or more in , 12 in 5.01vlH2
00 or more, exhibiting an effective magnetic permeability of 800 or more at 7.0MH2. Moreover, this material has a low coercive force of 0.05 to 0.2000, and a frequency of 3.0 to 5.0 when the loss coefficient Q is 1. It has the characteristic that it falls within the range of QMHz.

The magnetic abrasive of the present invention needs to contain small amounts of niobium oxide, vanadium oxide, and calcium oxide. Niobium oxide is a component for improving magnetic properties in a high frequency region, and is added in an amount of o,oos to 0.1% by weight.

If the amount is less than 0.005% by weight, the improvement in magnetic properties is insufficient, and if it is still more than 0.1% by weight, abnormal crystals will occur, and high-density firing at the theoretical density will be difficult. Become apart. On the other hand, vanadium oxide is a component for improving specific resistance, and is added within the range of 0.005 to 0.05% by weight. If this amount is less than 0.005% by weight, sufficient improvement in resistivity will not be achieved, and if this amount is more than 0.05% by weight, abnormal crystals will occur. Furthermore, calcium oxide acts in combination with vanadium oxide to suppress abnormal crystals caused by the presence of niobium oxide, and
It is a component that plays a role in improving processability and has a LO' old to 0.
It is used within a range of 30% by weight. This 16 or 0.01
If the amount is less than 4% by weight, the desired effect may not be achieved or
If it exceeds 0.30% by weight, the coercive force increases, which is not preferable.

The magnetic material of the present invention includes Fe2O355,0-57,0 mol/l/%, ZnO5,0-25,0 mol%, MnO40
, 0.00 niobium oxide to the raw material powder mixture essential for forming ferrite with a composition of 0-18.0 mol%.
5-0.1% by weight, vanadium oxide 0,005-0.
05% by weight and 0.01 to 0.30% by weight of calcium oxide are added in powder form, and after molding according to a conventional method, the theoretical density is 95 to 95% by weight at 1100 to 1400°C in a non-oxidizing atmosphere.
Primary firing until 98%, then a small amount of at least 800%
K9/c, 1100-140 while pressurizing l
It can be manufactured by performing secondary firing at 0° C. until the density reaches 99.8% or more of the theoretical density.

As mentioned above, when niobium oxide is added to manganese-zinc ferrite, abnormal crystals tend to occur and the sintered density decreases.
This is because pores of μm size are formed.

In the present invention, a raw material mixture in which vanadium oxide and calcium oxide are added together with niobium oxide is used, and this is formed into a dense coating layer in the secondary firing stage to close the communicating holes, and then the external layer is formed in the secondary firing stage. It is compacted under pressure to form a sintered body with desired magnetic properties.

When producing the magnetic material of the present invention, instead of the above-mentioned niobium oxide, vanadium oxide, and calcium oxide, substances that can be converted into these substances by firing, such as carbonates, bicarbonates, and hydroxides, may be used. can.

Further, the non-oxidizing atmosphere for the second firing can be formed using, for example, an inert gas or an inert gas with a controlled oxygen concentration, or can be formed by reducing pressure.

Pressure in the secondary firing can be performed using, for example, a hot isostatic press device.

The magnetic material of the present invention is a low-loss ferrite having a very large effective magnetic permeability in a high frequency region, and exhibits low coercive force and high specific resistance, so it is suitable as a magnetic rad core material for high-density recording. be.

Next, the present invention will be explained in more detail with reference to Examples.

Example: To a basic composition of 55.0 mol% Fe2O2, 8.0 mol% ZnO, and 37 mol% Mn, powders of niobium pentoxide, vanadium pentoxide, and calcium carbonate were added in the proportions shown in the table and mixed well. Calcinate at 850°C for 1.20 minutes.

Next, after pulverizing this calcined product, a small amount of polyvinyl alcohol was added as a binder to form a compacted powder, and the powder was pulverized at 1250 °C in a mixed atmosphere of 2% by volume of oxygen and 98% by volume of nitrogen.
Heat to 95% of theoretical density at ~1300°C. Next, this was sintered using a hot isostatic pressure apparatus at 1000:9/cJ and 1200° C. until it reached the theoretical density.

The physical properties of the magnetic material thus obtained are shown in the table below.

Bamboo 6 has the characteristic of no additives, and hananium oxide and calcium oxide are added to it, but Bamboo 4 has niobium oxide and calcium oxide added to it. Compared to Flat 6, there is a slight improvement in properties, but it is not as good as the composite additive effect of //63. Also, some improvement was observed with the addition of calcium oxide to Bian 1, but it was inferior to Tomo 3.

Therefore, a composite additive of niobium oxide, vanadium oxide, and cal/rum oxide is the best.

Patent Applicant TDC Co., Ltd. Agent Akira Agata

Claims (1)

[Claims] l Fe2O355,0-57,0 mol%, ZnO5,
0-25.0 mol%, MnO2, 0.0-18.0 mol/
0.005-01% by weight of niobium oxide and 0.0% vanadium oxide for manganese-zinc ferrite consisting of
05-0.05% by weight and calcium oxide 0.01-0
．． A magnetic material for magnetic recording, characterized in that it contains 30% by weight. 2 Fe2O355,0-57,0 mol%, Zr1O5
, 0-25.0 mol%, Mn0 0.005-0.1% by weight of niobium oxide, vanadium oxide 0, 005-0.05% by weight and Cal/Ram oxide 0.01-0.30% by weight are added in powder form, and after molding, the density is 95-98% of the theoretical density at 1100-1400°C in a non-oxidizing atmosphere. The first firing was carried out at a temperature of
1. A method for producing a magnetic material for magnetic recording, which comprises performing secondary firing at a temperature of 100 to 1,400° C. to achieve a density of 99.8% or more of the theoretical density.