JPH02168602A - Non-magnetic substrate for magnetic head - Google Patents

Abstract

PURPOSE:To make both thermal expansion coefficient and hardness nearly equal to those of a magnetic film structure body, and prevent the generation of cracks and exfoliation by providing rock salt type structure expressed by a specified composition formula. CONSTITUTION:Rock salt type structure expressed by the CoxNi2-xO2 (0.25<=x<1.0 or 1.2<x<=1.8) is provided. Dense sintered body having rock salt type structure of CoxNi2-xO2 is obtained by ordinary powder metallurgy method in which CoO and NiO are used as raw material. Characteristics wherein thermal expansion coefficient is 130-150X10<-7>/ deg.C and Vickers hardness is 500-700kg/mm<2> are obtained. Hence, the hardness is large, and abrasion and cracks of edge parts caused by the sliding of a tape can also be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (7) OshiriL The present invention relates to a nonmagnetic substrate for a magnetic head on which a metallic magnetic film is deposited.

・Conventionally, barium titanate,
Calcium titanate, alumina, etc. were used. However, since its coefficient of thermal expansion was significantly different from that of the magnetic film structure, the deposited magnetic M structure was easily separated by H, and the difference in coefficient of thermal expansion caused stress and cracks.

Furthermore, conventional materials have low hardness, and especially when high coercive force tape (so-called metal tape) is used, the non-magnetic substrate has a different hardness and abrasion resistance than the magnetic film structure, and the sliding with the magnetic tape is difficult. There was a problem in that the scratches caused by the movement caused uneven wear and other problems, which caused changes in the magnetic properties. In particular, when the hardness is low, there are noticeable drawbacks such as shortening the life of the magnetic head or causing deformation, cracking, and peeling of the nonmagnetic substrate.

-Rdan j1 unlucky- That is, the present invention provides CoxNi, xo, (however, 0.
The present invention relates to a nonmagnetic substrate for a magnetic head, which is expressed as 2≦×<1.0 or 1.2 (X≦1.8) and has a rock salt structure.

The present invention solves the above-mentioned drawbacks, and the handle has a thermal expansion coefficient of 130 to 150 x 10''/'C,
The object is to provide a material that has a Vickers hardness of 500 to 700 kg/mm and does not cause excessive chemical erosion reactions among other head constituent materials.

The present inventors studied many materials from this point of view, and first, Zn x M y Co, -x -'/0*
(However, M is Mn or Ni, O≦X≦0.4.0.
An oxide having a composition of 4≦y≦0.8, 0.8≦x+y≦1.0 was disclosed.

However, ZnO is difficult to sinter due to its high vapor pressure, and its composition of Mn is difficult, and it was found that the vapor contaminates the inside of the furnace, so further studies were conducted, and CoxNi,
-xo□ (where 0.2≦×<1.0 and l.

It has been found that an oxide having a composition of 2x≦1.8) also has similar characteristics.

Figure 1 shows the result when two components, Coo and NiO, are mixed.
It shows the value of the coefficient of thermal expansion from 00 to 400°C.

From this, it has been found that the coefficient of thermal expansion can be easily adjusted by changing the range of X, and that the above composition range is desirable for a magnetic head substrate.

Using Coo and NiO as raw materials, we obtain a sintered body of CoxNi, xO, which is dense and has a rock-salt structure, using ordinary powder metallurgy methods.It has a hardness higher than that of conventional products, and is resistant to wear due to tape sliding and etch areas. It was confirmed that there was less chipping and that it was superior to conventional materials.

"Maru JJL Among the oxides represented by the composition formula (:oxNi, -xo), those with the composition shown in Table 1 were prepared from Ni01Coo. Mixing and grinding were carried out in a wet ball mill in ethanol for 22 hours.
Time processed.

After drying, it was calcined at 1000°C in Ar, pulverized, arp-molded, and sintered at 1350°C in N. The obtained material was confirmed to be rock salt type by X-ray diffraction.

Other physical properties are shown in Table 1. For comparison, the physical properties of a conventional product (barium titanate) are also listed.

Table 1 "L1Ω force" As explained above, the non-magnetic substrate of this composition has a coefficient of thermal expansion,
Since the hardness is almost the same as that of the magnetic film discharged body, peeling and cracking can be prevented. Furthermore, uneven wear due to friction caused by sliding with the tape can be prevented, and the head has the advantage of excellent wear resistance and durability.

In addition, since it does not contain oxides with high vapor pressure, it is easy to control the composition, there is no need to worry about contaminating the furnace during sintering, it is easy to handle during the manufacturing process, and it has great economic effects. be.

[Brief explanation of the drawing]

Figure 1 shows the result when Coo and NiO are mixed and sintered.
It shows the value of the coefficient of thermal expansion from 00 to 400°C. Figure 1

Claims (1)

[Claims] (1) CoxNi_■_-xO_■ (However, 0.2≦
×<1.0 or 1.2<×≦1.8),
A nonmagnetic substrate for a magnetic head, characterized by having a rock salt type structure.