JPS61190703A - magnetic head - 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] Industrial applications The present invention relates to an improvement in the structure of a magnetic head.

Conventional technology Conventionally, magnetic heads have been constructed using soft magnetic permalloy, sendust, amorphous alloy, and Mn as magnetic core materials.
-Zn-ferrite or the like is used, and this is bonded or adhered to the substrate, or formed on the substrate by methods such as vapor deposition, sputtering, CvD, plating, etc.

Substrate materials for magnetic heads with such a configuration have been broadly classified into three types: glass substrates, single crystal substrates, and polycrystalline ceramic substrates.

Problems to be Solved by the Invention However, glass substrates do not contain alkali metals or C.
Since it contains a, it is chemically unstable under the environmental conditions during use, especially changes in humidity, and has poor machinability, making it unsatisfactory as a substrate for a magnetic head.

Single crystal substrates have the disadvantage of being too expensive. On the other hand, polycrystalline substrates can eliminate the above-mentioned drawbacks by selecting the composition, but they are made up of aggregates of minute crystal grains, and their wear resistance varies depending on the plane orientation of the crystals. When a magnetic head is constructed using the above-described method, when the substrate slides with a magnetic recording medium such as a magnetic tape, unevenness is generated on the substrate surface depending on the size of the crystal grains.

So-called "uneven wear" occurs, which deteriorates the contact between the magnetic head and the magnetic recording medium, resulting in a disadvantage that the output of the magnetic head decreases over time.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention has an average crystal grain size of 6 μm or less. This magnetic head is characterized in that a ceramic sintered body is used as a substrate, and a soft magnetic material is formed on this substrate as a magnetic core.

The inventors configured magnetic heads using high-density ceramic substrates with various crystal structures and average crystal grain sizes, and conducted actual running tests on magnetic tapes. It has been discovered that by using a substrate, the amount of uneven wear can be reduced and the decrease in the output of the magnetic head can be minimized. Furthermore, if the crystal structure of the material used belongs to the cubic system with no anisotropy, the difference in wear resistance due to surface orientation will be minimal, and therefore a decrease in the output of the magnetic head will not be a problem at all in practice. It became.

Example Examples are shown below.

Reagent grade iron oxide Ql) 161.3p and zinc oxide 81.
5 and p were weighed, wet mixed and ground in a ball mill for 16 hours, and dried to obtain a mixed powder. In the same way, a powder obtained by mixing 123.8 y of reagent grade zirconium oxide and 27.1 y of yttrium oxide, and a powder of 199.3 y of reagent grade barium carbonate were prepared. A powder was obtained in which 80.0 g of titanium oxide and p were mixed. The average particle size of the raw material powder used is
All except zinc oxide and barium carbonate are Q, 2-0.
It is 3 μm.

The mixed powder of these three types was calcined in air at 800° C. for 2 hours, and then ground again in a ball mill and dried.

These calcined powders were granulated by adding 10% by weight of pure water,
Uniaxial pressure molding was carried out in a mold at a pressure of 3oo6/cffl. Using alumina as a pressure medium, these molded bodies were made of TeSi (,
) At a temperature of 1000℃~1600℃ in the mold, 30o~6
Hot pressed for 2 hours at a pressure of 00KP/cnl, zinc ferrite, stabilized zirconia.

The average crystal grain size of barium titanate is 4 μm and 7 μm.

Each sintered body of 20 μm was obtained. The densities of these sintered bodies are all 99.5% or more of the true density, and the crystal structures of zinc ferrite and stabilized zirconia are cubic, and barium titanate is tetragonal. These sintered bodies were cut and polished to form substrates, and as shown in the figure, a magnetic head having a structure in which an amorphous magnetic material mainly composed of CO was sandwiched between these substrates was fabricated. In FIG. 1, 1 is a ceramic substrate, 2 is a magnetic gap, 3 is an amorphous metal magnetic material, and 4 is a window for winding.

A magnetic tape was slid against these magnetic heads at a relative speed of about 3.8111/sea, and changes in head output were measured. As a result, although there are differences depending on the composition, when using substrates with average crystal grain sizes of 7 μm and 20 μm, the head output was 5 to 10% after several tens of hours to 100 hours.
It decreased by about dB. In addition, when using a barium titanate substrate with an average crystal grain size of 4 μm, approximately 1.5
dB, the output decreased. A closer look at the magnetic head that had experienced a drop in output revealed that the tape sliding surface of the substrate had suffered uneven wear, resulting in unevenness of about 100 to 3008.

On the other hand, when using a zinc ferrite substrate and a stabilized zirconia substrate with an average crystal grain size of 4 μm, almost no uneven wear was observed, and the output decreased by 0.5 dB up to 100 hours.
It was below.

The inventors further created high-density ceramic sintered substrates with various average crystal grain sizes by changing the raw material powder, firing conditions, etc., and conducted experiments similar to those described above. As long as the substrate has a diameter of 6 μm or less, the amount of uneven wear is small regardless of the composition, and especially if the crystal structure belongs to the cubic system, uneven wear that would be a practical problem did not occur. . On the other hand, when the average grain size was 0.5 μm or less, it was difficult to cut with a normal slicing machine. Note that the configuration of the magnetic head is not limited to that shown in FIG.

Effects of the Invention The present invention provides a magnetic head using a high-density ceramic sintered body having an average crystal grain size of 0.5 μm or more and 6 μm or less, more preferably a cubic crystal structure, as a substrate; has stable performance over a long period of time without any reduction in output due to uneven wear of the substrate material when sliding with a magnetic recording medium such as a magnetic tape.

[Brief explanation of drawings]

The figure is a diagram showing an example of a magnetic head according to the present invention. 1...Substrate, 2...Magnetic gap, 3
・・・・・・Amorphous metal magnetic material, 4・・・・・・
Winding window. Name of agent: Patent attorney Toshio Nakao and one other person (-
&Ku 2 - I don't like it, - 3 - I'm begging for 11 days

Claims (2)

[Claims] (1) A ceramic substrate with an average crystal grain size of 5 μm or less is used, and a soft magnetic material is attached to this substrate as a magnetic core.
A magnetic head characterized by the following: (2) A magnetic head according to claim 1, characterized in that a ceramic having a cubic crystal structure is used as the material of the substrate.