JP3353379B2 - Non-magnetic ceramic material for magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structural non-magnetic ceramic material used in a magnetic head for performing magnetic recording and magnetic reproduction, and more particularly to a structure capable of preventing cracks and deterioration of magnetic characteristics due to a difference in thermal expansion. The present invention relates to a structure of a composition capable of improving mechanical strength and abrasion resistance.

[0002]

2. Description of the Related Art For example, storage of magnetic cards and magnetic tapes,
A slider, a spacer, a substrate, or the like made of a nonmagnetic ceramic material is used for a magnetic head for reproducing. As such a nonmagnetic ceramic material, a CaO—TiO ₂ system, a MnO—NiO system, or
A gO-NiO-based ceramic material is employed. A common property of these materials is that they have a coefficient of thermal expansion between 100 and 120.
The composition can be selected within the range of × 10 ⁻⁷ / ° C., the Vickers hardness must be 750 to 900 Hv, and the sintered body has a dense and smooth polished surface. .

[0003]

By the way, in recent magnetic heads, in order to improve the recording density, a high B
Mn-Zn ferrite material having a certain value is used.
However, since this Mn-Zn ferrite material has a large thermal expansion coefficient of 130 to 145 × 10 ^-7 / ° C., when the above-mentioned conventional non-magnetic ceramic material is used, the production and processing of a magnetic head are caused by the difference in thermal expansion coefficient between the two. There is a problem that cracks occur in the inside and magnetic properties deteriorate due to residual stress. Further, while the crystal structure of the Mn-Zn ferrite is of a spinel type, in the conventional non-magnetic ceramic material, the CaO-TiO ₂ material is of a perovskite type, and the MnO-NiO and MgO-Ni
Since the O-based material is different from the rock salt type, there is a problem that a step is generated in both members during processing of the magnetic head, or a difference in sliding characteristics with the magnetic tape is apt to occur, resulting in poor mechanical strength and abrasion resistance. There is a demand for the emergence of a non-magnetic ceramic material that can cope with the Mn-Zn ferrite.

The present invention has been made in view of the above-mentioned conventional situation, and can prevent cracks and deterioration of magnetic properties due to a difference in thermal expansion coefficient, and can improve mechanical strength and wear resistance, and furthermore, Mn. -It is an object of the present invention to provide a non-magnetic ceramic material for a magnetic head that can support Zn ferrite.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a method for producing NiO
10-40 mol%, MnO 25-75 mol%, and CoO
With respect to 100 wt% of a composition obtained by mixing 10 to 40 mol%, Z
A non-magnetic ceramic material for a magnetic head, characterized in that it is mainly composed of an oxide composite sintered body obtained by adding 1 to 10 wt% of nO.

The reason why the amounts of NiO and CoO are regulated is that if the amount of each additive is less than 10 mol%, a desired thermal expansion coefficient cannot be obtained, and if it exceeds 40 mol%, the hardness decreases. This is because the wear resistance deteriorates.
Also in the case of the above-mentioned MnO amount, the added amount is 25 mol%.
If it is less than the above, a desired coefficient of thermal expansion cannot be obtained, and the hardness is reduced to deteriorate the wear resistance. Also 75mol%
This is because the hardness is reduced even if the ratio exceeds the range.

Further, by adding the above ZnO, the wear resistance can be further improved, and sintering at a low temperature of 10 to 50 ° C. becomes possible. On the other hand, if the ZnO content is out of the range of 1 to 10% by weight, the effect of improving wear resistance cannot be obtained.

[0008]

According to the non-magnetic ceramic material for a magnetic head of the present invention, ZnO is added to a composition composed of NiO, MnO, and CoO, and the amount of these added is regulated.
As a result, a phase having a spinel-type crystal structure is dispersed, and a higher thermal expansion coefficient can be obtained as compared with the above-described conventional ceramic materials. As a result, the magnetic head M
It is possible to obtain a thermal expansion coefficient equivalent to that of the n-Zn ferrite material, and it is possible to avoid deterioration of magnetic properties due to cracks and residual stress generated during manufacturing and processing of the magnetic head. Moreover, since the mechanical strength and wear resistance can be improved, the above M
Properties suitable for n-Zn ferrite can be obtained,
It is possible to solve the problem that a step is generated between the two members at the time of processing the magnetic head or a difference is generated in the sliding characteristics with the magnetic tape, and the above-described demand is satisfied.

[0009]

Embodiments of the present invention will be described below. EXAMPLE 1 In this example, a nonmagnetic ceramic material for a magnetic head according to the present invention was manufactured, and a test performed to confirm the effect of the nonmagnetic ceramic material will be described.

[0010]

[Table 1]

[0011]

[Table 2]

In this test, as shown in Table 1, commercially available manganese carbonate (MnO) and nickel oxide (Ni
O), cobalt oxide (CoO), and zinc oxide (Zn)
O) was used. These raw materials were weighed so as to have the composition ratios shown in Table 1, and were wet-mixed using a ball mill. The mixed powder was dried, and then calcined at 900 ° C. for 2 hours. Next, this calcined body was finely pulverized and granulated, and then 1.0t / c
A molded body was formed by applying a pressure of m ² . Next, the molded body was fired in the atmosphere at a temperature of 1300 to 1350 ° C. for 2 hours to obtain a sintered body. As a result, a number of samples were prepared (No. 1 to No. 31 in the table). In the tables, the asterisks are outside the claims of the present invention.

The thermal expansion coefficient and Vickers hardness (Hv) of each of the samples No. 1 to No. 31 were measured, and the bending strength (Kg / cm ² ) and wear resistance of each sample were examined. . In this wear test, the sample was run for a certain period of time with the magnetic recording tape in contact with each of the samples, and the ratio of the wear of each sample to the wear of the Mn-Zn ferrite was expressed.

As is clear from Tables 1 and 2, Mn
Sample No. 1 and NiO, Co with O
Sample Nos.
In samples 6, 9, 10, and 14, all of the samples had a thermal expansion coefficient of less than 120 × 10 ⁻⁷ / ° C., and did not match the thermal expansion coefficient of Mn—Zn ferrite. The sample No. 19 having the MnO content smaller than the claimed range and the NiO, CoO
In the case of sample Nos. 15 and 18 whose amount is larger than the claims,
The coefficient of thermal expansion is 145 × 10 ⁻⁷ / ° C. or more, which is slightly too large, which is not appropriate. Further, in the case of Samples 20, 25, 26, and 31 in which the amount of ZnO was out of the claims, a satisfactory value was obtained for the coefficient of thermal expansion, but the value was 0.2 in the wear resistance test.
It is as low as 61-0.86.

On the other hand, Samples 3, 4,
7, 8, 11 to 13, 16, 17, 21 to 24, 27 to
In the case of No. 30, all the samples have a thermal expansion coefficient of 120 to 140 × 10 ^−7.
/ ° C and a value substantially equivalent to that of the above Mn-Zn ferrite are obtained. In addition, Vickers hardness is as high as 550-760Hv,
The transverse rupture strength is 2000 kg / cm ² or more. Furthermore, a satisfactory value of 0.95 to 1.30 has been obtained in abrasion resistance.

As described above, according to this embodiment, the predetermined amount of N
Since a sintered body was formed by adding a predetermined amount of ZnO to a composition comprising iO, MnO, and CoO, it was possible to obtain a thermal expansion coefficient substantially equal to that of Mn-Zn ferrite for a magnetic head. It can avoid the deterioration of the magnetic properties due to cracks and residual stresses during the production and processing of the steel, and can also improve the bending strength and abrasion resistance, resulting in a difference in the sliding properties with the magnetic tape. Can be resolved.

[0017]

As described above, according to the non-magnetic ceramic material for a magnetic head according to the present invention, NiO is contained in an amount of 10 to 40 mol.
%, MnO is 75 to 25 mol%, and CoO is 10 to 40 mol%
Since 1 to 10 wt% of ZnO is added to the mixed composition, cracks and deterioration of magnetic characteristics due to a difference in thermal expansion when Mn—Zn ferrite is employed for a magnetic head are obtained, and mechanical This has the effect of improving the mechanical strength and abrasion resistance and providing the sliding characteristics suitable for the above-mentioned Mn-Zn ferrite.

Claims (1)

(57) [Claims] 2. A method according to claim 1, wherein the NiO is 10 to 40 mol%, the MnO is 75 to 25 mol%, and the CoO is 10 to 40 mol%.
ZnO is added to 100 wt% of the mixed composition.
A non-magnetic ceramic material for a porcelain head, comprising a main component of an oxide composite sintered body to which 10 to 10 wt% is added.