JPH0580045B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improvement in the construction of a magnetic head.

Conventional technology Conventionally, magnetic heads have been constructed by using soft magnetic permalloy, sendust, amorphous alloy, Mn-Zn-ferrite, etc. as the magnetic core material, and bonding or adhering this to a substrate, or depositing it on the substrate.・
Materials formed by sputtering, CVD, plating, etc. have been used.

In a magnetic head with such a configuration, unless the soft magnetic material and the substrate material have the same coefficient of thermal expansion, or the difference between them is extremely small, stress will be generated at the interface between the two materials due to temperature changes, causing cracks. or the magnetic properties of the soft magnetic material deteriorate due to the magnetostrictive effect. For this reason, a substrate material whose thermal expansion coefficient can be freely changed according to the type and composition of the soft magnetic material used is required, such as crystallized glass, CaO-SrO- _TiO2 ceramic substrates (Japanese Unexamined Patent Publication No. 52-57218),
NiMnO ₂ ceramic substrates (Japanese Unexamined Patent Publication No. 16399/1983) were used. The coefficient of thermal expansion of these substrate materials can be selected from a wide range by adjusting the composition.

Problems to be solved by the invention However, crystallized glass and CaO−SrO−
Because TiO ₂ -based substrates contain alkali metals or Ca as components, they are chemically unstable against environmental conditions during use, especially changes in humidity, and when these substrates are used to construct a magnetic head. However, there were problems with weather resistance and durability. on the other hand,
When using a NiMnO ₂ -based substrate, there is no problem with temperature changes, but since MnO is easily oxidized to Mn ₂ O ₃ when heated in air, it may not have sufficient thermal stability. Moreover, since the firing atmosphere for the substrate itself must be non-oxidizing, the production cost is high.

Means for Solving the Problems In order to solve the above problems, the present invention has a rock salt type crystal structure and a complex oxide ZnxNi _1-x O (O<x
This magnetic head is characterized by using a substrate whose main component is 0.5) and having a soft magnetic material formed as a magnetic core on this substrate.

As a result of research, the inventors have developed a product with excellent moisture and heat resistance.
By dissolving ZnO in NiO, the coefficient of thermal expansion can be increased.
It has been found that the temperature can be adjusted within the range of 100 to 140×10 ^-7 /°C. ZnO has a hexagonal crystal structure,
By setting ZnxNi _1-x O as a solid solution with NiO, 0<x
Within the range of 05, it has a rock salt type crystal structure.

A magnetic head constructed using this ZnxNi _1-x O substrate has excellent weather resistance and durability characteristics, and is easy to manufacture since there is no need to particularly adjust the atmosphere during firing regarding the substrate material itself.

Example Examples are shown below.

After weighing reagent-grade nickel oxide and zinc oxide, and mixing them in a wet ball mill for 16 hours,
Dry at 150℃, the molar ratio of NiO and ZnO is NiO:
ZnO=1:0, 4:1, 2:1, 1:1, 1:
A mixed powder of 2,1:4,0:1 was obtained. Add 10% by weight of pure water to this mixed powder and granulate it to 300Kg/cm ²
It was formed under uniaxial pressure in a mold at a pressure of . This formed body is placed in a SiC mold using alumina as a pressure medium,
2 at a humidity of 1100℃~1500℃ and a pressure of 300Kg/ ^cm2
Time hot pressed. The obtained sintered body was subjected to phase identification using X-ray diffraction, density measurement using Archimedes method, and particle size observation using a scanning electron microscope. The thermal expansion coefficient was measured between 25°C and 400°C using a dilatometer. As a result, in X-ray diffraction, NiO:ZnO=1:0, 4:1, 2:1,
The 1:1 samples showed a diffraction pattern with rock salt type crystal structure, and these sintered bodies were ZnxNi _1-x O (0<x
0.5). On the other hand, NiO:
In the samples with ZnO=1:2 and 1:4, the diffraction pattern of ZnO is
In the sample with NiO:ZnO=0:1, a ZnO diffraction pattern appeared. In addition, the density measurement results are similar to that of NiO.
Although it changes depending on the mixing of ZnO, all samples are 99.5% of the theoretical density determined from X-ray diffraction.
That's all. The grain size of the sintered body was found to be 5 to 10 μm as observed using a scanning electron microscope. As shown in Figure 1, the coefficient of thermal expansion is 140×10 ^-7 for single oxide NiO.
degree and the maximum, and the minimum for Zn _1/2 Ni _1/2 O is 100×
10 ^-7 /°C, and it varied continuously between them.

Therefore, Zn _1/5 whose thermal expansion coefficient is 120×10 ^-7 /℃
A sintered body of Ni _4/5 O (ZnO:NiO=1:4) was selected, cut and polished to obtain a substrate with a surface smoothness R _nax of 0.1 μm. This substrate has a thermal expansion coefficient of 120×10 ^-7 /
A magnetic head as shown in Fig. 2 was fabricated from a soft magnetic amorphous alloy containing Co as a main component at a temperature of 1.5°C. In Figure 2, 1 is the board, 2 is the magnetic gap, and 3
4 is an amorphous metal magnetic film, and 4 is a window for winding.

To explain the process of creating a magnetic head, an insulating layer mainly composed of SiO ₂ is formed to a thickness of about 1 μm on a well-cleaned substrate using a sputtering device, and then a soft magnetic amorphous alloy thin film is formed to a thickness of 30 μm. to form. A substrate is attached on top of this using an inorganic adhesive to create A and B in Figure 2. In B, a groove is formed to serve as the window for winding wire 5, and a glass for gap formation is formed.
Sputter it onto the magnetic gap forming surfaces of both parts A and B, and finally hot-bond parts A and B. This bonded body is wound with wire to form a magnetic head.

In addition to the magnetic head using the Zn _1/5 Ni _4/5 O substrate created in this way, we also prepared a magnetic head with a thermal expansion coefficient for comparison.
120×10 ^-7 /℃ crystallized glass and CaO−SrO
-Magnetic heads were prepared in the same manner using TiO ₂ ceramics as the substrates. A so-called "metal tape," which uses metal magnetic powder as a magnetic recording medium, is slid against these three types of magnetic heads at a relative speed of approximately 3.8 m/sec to determine the output changes, wear resistance, and environmental resistance of the heads. was tested. As a result, under the normal environment of 23°C and 50% humidity, there were no particular differences in the magnetic head characteristics depending on the type of substrate, but when the environmental conditions were 23°C and 50% humidity,
There were no particular differences in magnetic head characteristics depending on the type of substrate, but under environmental conditions of 23°C and 10% humidity,
In magnetic heads with substrates made of crystallized glass and CaO-SrO- _TiO2 ceramics, it was observed that the head output decreased by several dB within a few hours after the start of measurement. When we closely observed these magnetic heads, we found that metal powder from the magnetic tape had adhered to the surface of the substrate, creating irregularities. On the other hand, Zn _1/5 of the present invention
Such adhesion does not occur on the Ni _4/5 O substrate;
Therefore, no reduction in the output of the magnetic head occurred. Similar tests were also conducted under other environmental conditions, such as high temperature and high humidity, high temperature and low humidity, and low temperature and high humidity.
The magnetic head using the Zn _1/5 Ni _4/5 O substrate exhibited stable characteristics without any problems in magnetic head output or wear resistance. On the other hand, magnetic heads using other substrate materials have had problems such as decreased output and wear resistance as described above.

From the perspective of wear resistance, substrate materials that wear too much are problematic, and if the crystal structure has anisotropy, the amount of wear will vary depending on the crystal orientation, causing unevenness on the substrate. It will be done. From this point of view, a substrate material whose crystal structure is a rock salt type satisfies the required characteristics.

In the above example, the coefficient of thermal expansion is 120×10 ^-7 /
℃ is used, but the soft magnetic material is not limited to this, and as long as the thermal expansion coefficient is within the range of 100×140×10 ^-7 /℃, NiO By changing the solid solution ratio of ZnO and ZnO, an optimal substrate can be provided. Furthermore, the method of manufacturing the magnetic head is not limited to the method described in the embodiments.

Furthermore, the substrate material used in the present invention has ZnxNi _1-x O as its main component, and no problems will arise even if additives are added to improve machinability or sintering properties. .

Effects of the Invention The present invention is a magnetic head using a substrate containing ZnxNi _1-x O (0<x0.5) as a main component and having an adjusted coefficient of thermal expansion, and the magnetic head has a sliding contact with a magnetic recording medium. It has stable performance without causing any problems, and has excellent environmental resistance and abrasion resistance.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between the coefficient of thermal expansion of ZnxNi _1-x O-based material and the value of the composition ratio x, and FIG. 2 is a diagram showing a magnetic head according to the present invention. 1... Substrate, 2... Magnetic gap, 3... Amorphous metal magnetic film, 4... Winding window.

Claims (1)

[Claims] 1 Composite oxide with rock salt type crystal structure
A magnetic head characterized by using a substrate containing ZnxNi _1-x O (0<x0.5) as a main component, and forming a soft magnetic material as a magnetic core on this substrate.