JPH0782616B2 - Non-magnetic substrate for magnetic head - Google Patents

Description

TECHNICAL FIELD The present invention relates to a non-magnetic substrate for a non-magnetic magnetic head for depositing a metallic magnetic film.

Conventional technology Conventionally, barium titanate,
Calcium titanate, alumina, etc. were used. However, since the coefficient of thermal expansion was greatly different from that of the magnetic film structure, the vapor-deposited magnetic film structure was easily peeled off,
Further, a stress may be generated due to the difference in the coefficient of thermal expansion and a crack may be generated.

Furthermore, the conventional material has low hardness, and especially when a high coercive force tape (so-called metal tape) is used, the non-magnetic substrate is different from the magnetic film structure in hardness and abrasion resistance, so that the non-magnetic substrate slides on the magnetic tape. There is a problem in that the friction generated by the movement causes uneven wear and the like, resulting in changes in the magnetic characteristics. Particularly when the hardness is low, the shortcomings of shortening the life of the magnetic head and causing deformation, cracking and peeling of the non-magnetic substrate are remarkable.

The present inventor investigated many materials in order to solve the above-mentioned drawbacks, and as a basic composition, Co _x Ni _2-x O ₂ (however, 0.2 ≦
It has already been disclosed that an oxide having a composition of x ≦ 1.8) is effective. In addition, we examined the additive materials and found that MnO, Ti
It has already been disclosed that the addition of 0.1 to 5 wt% of O ₂ , Al ₂ O ₃ or CaO is effective.

In addition, as a result of continuing to study the additive material with CoO and NiO as the basic composition, when 1 to 5 wt% Y ₂ O ₃ or 0.1 to 1 wt% TiN, or 0.3 to ₂ wt% B ₂ O ₃ was added However, since it has the above-mentioned characteristics, this is also disclosed.

Problems to be Solved by the Invention The present invention solves the above-mentioned drawbacks, and specifically,
Has a coefficient of thermal expansion of 0 ~ 150x10 ^-7 / ℃, Vickers hardness 600
It is an object of the present invention to provide a material that has the above characteristics and that does not cause an excessive chemical erosion reaction between other head constituent materials.

Structure of the Invention That is, the present invention is based on Co _x Ni _{2 -x} O ₂ (where 0.2 ≦ x ≦ 1.8) as a basic composition, and 1 to 5 wt% of Si is used for 100 wt% of the composition.
The present invention relates to a non-magnetic substrate for a magnetic head, to which O ₂ is added.

Means and Actions for Solving Problems The present invention further provides Co _x Ni _2-x O ₂ (where 0.2 ≦ x ≦ 1.8)
As a result of continuing to study the additive material with the basic composition of
It was found that when ₁ to 5 wt% of SiO ₂ was added to 100 wt%, an improvement in density and hardness was observed.

SiO ₂ has a good wettability with NiO and CoO, and the density increases when 1 wt% or more is added. However, more than 5 wt% S
Addition of iO ₂ is not preferable because it causes segregation at the grain boundary portion, resulting in a decrease in hardness and coefficient of thermal expansion.

The addition may be performed singly or in combination with each other, and the combination with the already disclosed additive is also effective. It is desirable to adopt a combination corresponding to the desired hardness and thermal expansion coefficient.

Each commercially available oxide is used as a raw material, weighed to have a desired composition, and mixed by a ball mill. Mixing is carried out, for example, in a wet ball mill in ethanol for 10 to 30 hours.

After drying, CIP molding, calcination in Ar at 850-1100 ℃,
Then, it is crushed using a coarse crusher and sieved with a sieve of 100 to 200 μm.

The calcined powder can be further processed, for example, in a wet type ball mill in ethanol.
Treat for ~ 72 hours and pulverize to 1 μm or less.

After granulating this, it is CIP molded and sintered, for example, in N ₂ at 1230 to 1400 ° C., and then subjected to HIP treatment. HIP processing condition is 80
0 to 1200 kg / cm ² , 1200 to 1350 ° C., and 1 to 2 hours are desirable.

It was confirmed that the thus-obtained sintered body had a dense and rock-salt structure, was less likely to cause friction and chipping at the edge portion due to the sliding of the tape, and was superior to conventional materials.

Example CoO and NiO were used as raw materials and adjusted so as to have a Co _x Ni _{2 -x} O ₂ (x = 1.0) composition and mixed. Mixing was carried out in ethanol with a wet ball mill for 20 hours.

This was calcined in Ar at 1000 ° C., then roughly crushed and sieved at 150 μm. Further, it was finely pulverized for 70 hours with a wet ball mill of ethanol.

SiO ₂ was added to this pulverized powder in the ratio shown in Table 1, and after CIP molding, N ₂ was added.
Sintered at 1400 ° C in medium. The density of the sintered body was a high value even if the HIP treatment was not performed.

Table 1 shows the relative density, Vickers hardness (Hv), and coefficient of thermal expansion (α) of the sintered body. In the table, the characteristics of barium titanate (Citabari) are also shown as a comparative example.

EFFECTS OF THE INVENTION As described above, (1) the non-magnetic substrate having the composition of the present invention can obtain substantially the same thermal expansion coefficient and hardness as the magnetic film structure.

Therefore, the peeling of the magnetic film structure and the occurrence of cracks can be significantly prevented.

(2) Further, by increasing the hardness, it is possible to shorten the life of the magnetic head and suppress the deformation and cracking of the non-magnetic substrate, and there is an advantage that the wear resistance and durability of the head are particularly excellent.

Claims (1)

[Claims] 1. A magnetic head characterized in that Co _x Ni _2-x O ₂ (where 0.2 ≦ x ≦ 1.8) is used as a basic composition, and 1 to 5 wt% of SiO ₂ is added to 100 wt% of the composition. Non-magnetic substrate.