JPS63217515A - Magnetic head - Google Patents

Abstract

PURPOSE:To facilitate production of a magnetic head so to improve the yield thereof and to decrease seizure and uneven wear so as to obtain high reliability by using zirconia ceramics having a prescribed compsn. as a substrate material. CONSTITUTION:Thin amorphous alloy films 1 essentially consisting of Co are formed on both faces of a zirconia ceramics substrate 2 essentially consisting of ZrO2 and CeO2 and having 80/92-30/70 molar ratio of CeO2/ZrO2 and SiO2 films are formed as protective layers thereon. The substrates 2 on both faces of which glass layers are further formed are prepd. Three sheets of the former and four sheets of the latter are alternately laminated and are adhered at a glass welding temp. to obtain a laminated block 3. Core half bodies 4, 4' are obtd. by cutting the block according to the prescribed azimuth angle. The polished butt surfaces of the core half bodies 4, 4' are adhered via thin films consisting of SiO2 and adhesive glass to obtain a gap forming bar 5. The bar is cut according to the pitch of the layers to form sliced bars 6. The bars are cut according to the pitch of windings, by which head chips are obtd. The magnetic head is formed by using such head chips.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic head suitable for recording high frequency signals on a high coercivity magnetic recording medium used for video tape recorders (VTRs), digital audio, and the like.

Conventional Technology It is well known that it is advantageous to increase the coercive force Hc of a magnetic recording medium in high-density magnetic recording and reproducing devices such as VTRs and digital audio. A strong magnetic field is required to record. However, the ferrite material currently widely used in magnetic heads has a saturation magnetic flux density of about 4,000 to 5,000 Gauss, so there is a limit to the strength of the recording magnetic field that can be obtained, and the coercive force of the magnetic recording medium is about 1,000 Oe or more. This has the disadvantage that records are insufficient.

On the other hand, magnetic heads using crystalline magnetic alloys or amorphous alloys such as Fe-Al-3i alloy (referred to as sendust) and Ni-Fe alloy (permalloy), which are collectively known as metal magnetic materials, In general, it has superior features such as higher saturation magnetic flux density and less sliding noise than ferrite materials, but it has the drawbacks of being difficult to process and having a low yield, resulting in high costs.

Problems to be Solved by the Invention In particular, when a metal magnetic thin film is used as the main core, it is usually deposited by a method such as vapor deposition or sulfur battering.
After being formed on a suitable substrate, a metal magnetic thin film is bonded using the same material as the substrate, and then processed and made into a head. However, strict conditions are required for such a substrate.

For example, the thermal expansion coefficient of the substrate should be close to that of the metal magnetic thin film in order not to deteriorate the magnetic properties of the metal magnetic thin film, it should have good workability, and it should wear moderately when sliding with the tape and not cause uneven wear. It is. Materials that fully satisfy these conditions are extremely limited, and conventionally, ferrite or crystal glass has been used, but these have advantages and disadvantages, and selection of an appropriate substrate material has been an important issue.

Means for Solving the Problems The present invention attempts to solve the above problems by using zirconia ceramics as the substrate. Zirconia ceramics has a coefficient of thermal expansion of 90
~130xlO7 is close to that of metal magnetic thin films, precision processing is possible with metal tools, excellent heat resistance, moderate abrasion resistance, etc. Metal magnetic thin films are used as the main core. It has desirable properties as a substrate material for magnetic heads. In particular, those containing 8-30% of CeO□ as a stabilizing material have a thermal expansion coefficient of 100-130xl.
O°7, which matches well with that of a metal magnetic thin film, and also has characteristics necessary for the substrate of the above-mentioned magnetic head, so it has extremely desirable characteristics.

By using zirconia ceramics as the working substrate material, it is easy to manufacture high-performance magnetic heads with a metal magnetic thin film as the main core, improving yields and greatly reducing manufacturing costs, as well as reducing seizure and uneven wear. A highly reliable head can be provided.

Embodiment FIG. 1 is a perspective view of a magnetic helad showing the structure of the present invention. It has a structure in which zirconia ceramics (2) sandwich both sides of the metal magnetic thin film il+, which is the main core. A specific method for manufacturing this head will be shown below.

Example 1 As shown in FIG.
/84, thermal expansion coefficient L20xlO°7)
Amorphous alloy thin Si with a thickness of 21 μm mainly composed of
A SiO□ film (not shown in the drawing) with a thickness of 0.5 to 1 μm is formed thereon as a protective layer. Furthermore, we prepared 3 μm thick glass layers (omitted in the drawing) on both sides of the same zirconia ceramic substrate as above, 3 of the former and 4 of the latter (however, the outer layer of the substrate was laminated with glass). layer is formed only on one side)
are alternately laminated and bonded at a glass fusing temperature (500° C.) to obtain a laminated block 3.

Next, the core half 4 is cut according to a predetermined azimuth angle as shown by the dotted line in FIG. After that, core half 4.
After polishing the abutting surfaces of 4゛, a thin film of S i 02 and adhesive glass is formed as a gap material so as to have a predetermined gap length, and a gap forming bar is formed by heating (500℃) in an electric furnace and bonding. Get 5. Thereafter, the slicer 6 shown in FIG. 6 is obtained by cutting according to the lamination pinch as shown by the broken line, and the head as shown in FIG. 1 is obtained by cutting according to the winding groove pitch as shown by the broken line. You get chips. The head chip is temporarily attached to the base, and the magnetic head is completed through processes such as curved surface processing and polishing of the tape sliding surface, and winding.

In the above process, zirconia ceramics are used as the substrate and holding material for the metal magnetic thin film, which is the main core, so for its good workability, precise cutting as shown in Figure 3.5.6 is required. It was easy to process and could be manufactured with good yield. Furthermore, since the coefficient of thermal expansion was close to that of the amorphous alloy Fi film, the magnetic properties of the obtained head were good with little deterioration due to the effects of magnetostriction and the like.

In addition, it has excellent heat resistance, so there is no problem when heated to about 500℃ (glass can be used for adhesion, it has excellent corrosion resistance, and it also has excellent resistance to sliding with tape). Since the head has an appropriate abrasion resistance, uneven wear is less likely to occur and a good sliding surface can be maintained, resulting in a highly reliable head.

Example 2 Instead of the amorphous alloy thin film l of Example 1, a Sendust thin film of 21 μm was deposited on both sides of the zirconia ceramic substrate 2 (CeO2/ZrO2 molar ratio 24/76, thermal expansion coefficient 130xlO7) by vacuum deposition. Form into a thick layer. Otherwise, the head can be created using the same process as in Example 1. In the case of this example, due to the heat resistance of the sendust thin film, the heating temperature when obtaining the laminated blocks and gap forming bars can be approximately 800°C. Therefore, adhesive glass with a high fusing temperature (800° C.) was used.

In this case as well, there was no problem with the heat resistance of zirconia ceramics, and the magnetic properties and reliability of the thus obtained magnetic head were as good as in Example 1.

In addition to the composition of the zirconia ceramics used in the above examples, the CeO□/ZrO2 molar ratio is 8/92 to
If it was in the range of 30/70, there were some differences in each characteristic, but almost the same effect could be obtained.

Effects of the Invention As described above, the present invention uses zirconia ceramics as the substrate on which the metal magnetic thin film, which is the main core, is deposited and as the holding material. It is easy to perform precise cutting, and its thermal expansion coefficient is close to that of amorphous alloy ff1ll and Sendust thin film, so it exhibits good magnetic properties with little property deterioration due to the effects of magnetostriction, etc., and has excellent heat resistance. Therefore, it is possible to manufacture a highly reliable head because it can be heated to about 800° C., glass can be used for bonding, and it has excellent corrosion resistance. Furthermore, it has appropriate abrasion resistance when sliding with the tape, so it has many equivalent features that cause less uneven wear and can maintain a good sliding surface.It also has good magnetic properties and is highly reliable. A high-quality magnetic head can be manufactured at low cost with good processing yield.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the structure of the magnetic head of the present invention, and FIG.
3, 4, 5, and 6 are perspective views illustrating a method of manufacturing a head in an embodiment of the present invention. 1... Metal magnetic thin film, 2... Zirconia ceramics, 3... Laminated block, 4.4゛... Core half pair, 5... ... Gap forming bar, 6... Slice bar. Name of agent: Patent attorney Toshio Nakao Written by: 231 Figure 4 Figure 6

Claims (3)

[Claims] (1) A magnetic head having a structure in which both sides of a metal magnetic thin film, which is the main core, are sandwiched between zirconia ceramics. (2) Zirconia ceramics mainly consists of ZrO_2 and C
The magnetic head according to claim 1, wherein the magnetic head is made of eO_2 and has a molar ratio of CeO_2/ZrO_2 in the range of 8/92 to 30/70. (3) Claim (1) characterized in that the metal magnetic thin film is an amorphous alloy or Sendust thin film.
The magnetic head according to any one of item (2) and (2).