JPS5911524A - Manufacture of magnetic head - Google Patents

Abstract

PURPOSE:To attain a magnetic head having high accuracy of size, excellent magnetic circuit characteristics and wear resistance, by forming a sliding plane with a recording medium of a chip constituting a magnetic head by coating a soft magnetic material thereupon by means of a low-presure plasma flame spray coating method. CONSTITUTION:A metallic mold 5 having a chip part of the magnetic head engraved is prepared, partition plates 6, 7 made of alumina having 0.7mu thickness are inserted respectively as a gap constituting member, a masking plate 9 is inserted to a guide 9 of the metallic mold 8, and a chip 10 is formed by applying the plasma flame spray to the soft magnetic material powder by an Ar plasma flame under output condition of 900A current and 80kVA power at low pressure of 50Torr. The soft magnetic material has 325-mesh (45mum) average particle diameter. The chip of the magnetic head manufactured from a material consisting of 9.7wt% Si, 7.1wt% Al and the balance Fe, has excellent magnetic circuit characteristics and wear resistance.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method of manufacturing a magnetic head, and more particularly, to a method of manufacturing a magnetic head, and more particularly, to a method of manufacturing a magnetic head that has excellent wear resistance without changing the optimum magnetic characteristics. The present invention relates to a method of manufacturing a magnetic head that can be easily obtained.

[Technical background of the invention and its problems]

A magnetic head constitutes the main part of a magnetic recording medium device such as an audio device or a VTR (video tape recorder), and its main components are a chip, a yoke, and a coil. FIG. 1 is a schematic diagram showing the main parts of such a magnetic head. In the figure, the magnetic head is comprised of chips 1a and 1b disposed with a gap 2 in between, and a yoke 3 and a coil 4.

Among these, the chip that constitutes the sliding part with the magnetic recording medium is one of the most important. The magnetic material used to manufacture this chip has the following magnetic properties: (1) high magnetic permeability, (2) small magnetic flux, and (3)
) Low crystal anisotropy is required. At the same time, mechanical properties such as (1) excellent wear resistance and (2) good workability are required.

However, in reality, it is difficult to obtain a material that satisfies all of the above characteristics, including manufacturing problems, and therefore, depending on the purpose of use, it is difficult to obtain a material that satisfies all of the above characteristics. The reality is that this is the case.

For example, Sendust alloy consisting of i+"6-5%kl-10%Si, which is commonly used as a material for magnetic heads, has excellent magnetic properties and wear resistance, but it is difficult to process. Sendust alloys are generally produced by casting, but during production, the grains become coarse.
It is large in the direction of Ll, and therefore has the problem that a so-called "chip" phenomenon is likely to occur, in which a part of the casting is missing during processing. Historically, due to large crystal grains, when used as a magnetic head, differences in the crystal orientation of the crystal grains caused variations in the wear of the sliding parts, causing the sliding surface to become rough. In addition, there are problems such as chipping occurring at the gap portion of the chip. FIG. 2 is a cross-sectional view of the polished surface of a polycrystalline body of Sendust alloy produced by casting, which was puff polished for about 5 minutes. As is clear from the figure, each grain (A-M) has a size of about 0.2 to III, and the polished surface is about 0.
．． It can be seen that it has irregularities of about 3 μm. This indicates that the crystal grains have become coarse 2 and that differences in the wear feet are caused by differences in the crystal orientation of these crystal grains.

It is also possible to use a permalloy alloy consisting of 40-85% Ni and the balance 1 = 'e, but although this material has excellent magnetic properties, it has poor wear resistance and is not practical. Furthermore, there are magnetic heads that use amorphous alloys, but manufacturing a magnetic head with a foil-like laminated structure requires complicated processes and requires excellent durability. V that requires abrasion resistance
When used in a TR river magnetic head, etc., it has a problem of poor wear resistance.

The above-mentioned materials are usually produced and processed by casting, molten metal quenching, etc., but on the other hand, a method of forming faceted chips by thermal spraying is also used. The thermal spraying method has the advantage of being able to form a film at a fairly high speed and forming chips with a uniform composition. However, since the treatment is carried out using -C in air, there are problems such as the oxidation of the abrasive material or the formation of small holes (bores) in the V-chip. Therefore, it is extremely difficult to use soft magnetic materials that contain a relatively large amount of aluminum, etc.191, as the aluminum etc. oxidizes and dries up. It is desired to obtain a magnetic head using a soft magnetic material having such a composition because it has a composition that provides an optimum value of or contains a relatively large amount of the above-mentioned aluminum and the like.

[Purpose of the invention]

An object of the present invention is to provide a method for manufacturing a magnetic head that eliminates the above-mentioned problems and easily obtains a magnetic head with excellent wear resistance without changing the optimum magnetic characteristics. It is about providing.

[Summary of the invention]

The method for manufacturing a magnetic head of the present invention is characterized in that at least a portion of a chip constituting the magnetic head, including a sliding surface with a recording medium, is coated with a soft magnetic material by a low-pressure plasma spray coating method. It is something to do.

In the following, the invention will be explained in more detail.

In the magnetic head OPA manufacturing method of the present invention, a chip constituting the magnetic head is manufactured by a low-pressure plasma spray coating method, for example, as follows.

That is, a mold having a predetermined shape of a chip constituting the magnetic head is prepared, and a masking plate or the like is attached to this mold as necessary. Then, the mold is placed in a low pressure environment, and a soft magnetic material is plasma sprayed using an argon (Ar) 7' plasma flame or the like, and the mold is laminated to form a chip of 8A.

The entire chip may be manufactured by low-pressure Zoramasma spraying, or a part may be formed using another magnetic material and only the part including the sliding movement may be manufactured by low-pressure plasma spraying. It's okay.

Furthermore, a soft magnetic material may be directly attached to the yoke constituting the magnetic head using a type A method by low-pressure plasma spraying.

In addition, using a mold that has the shape of the magnetic head part itself together with the Gatsu f component material shortens the post-processing process and reduces near net shape.
t 5 hape ) is preferable because it provides good formability. It is also possible to manufacture a magnetic head by manufacturing individual chip materials and then machining them together.

The chips 7'' manufactured in the above manner are then annealed at a temperature of about 800°C in a transformer arc, if necessary, and then precision-polished into a predetermined shape.Then, they are removed from the mold and magnetically recorded. After polishing the portion that forms the sliding movement with the medium, the magnetic head can be used by performing predetermined operations together with the yoke, coil, etc.

In the present invention, the conditions for low-pressure plasma spray coating at the time of manufacturing the chip are not particularly limited as long as the conditions allow the application of the magnetic material.

As the soft magnetic material used in the present invention, any material having good magnetic properties and wear resistance can be used. Such soft magnetic materials include an alloy consisting of 3 to 12% aluminum (Al), 4 to 12% silicon (Si), and the balance iron (Fe), or Ni 40%. ~85 car j
d%, molybdenum (Mo) 0-6%, niobium (N
b) An alloy containing 0 to 7% by weight and the balance consisting of chromium (Cr), etc. can be mentioned.

[Embodiments of the invention]

Example 1 As a soft magnetic material, 325 meshes (45μ
A mixed powder having an average particle size of 9.7M<Asahi% silicon, 761% aluminum, and the balance iron was prepared.

On the other hand, the tip of a magnetic head shaped as shown in Fig.
A mold 5 with carved parts was prepared, and an alumina cut plate 6°7 with a thickness of 0.7μ01 was inserted as a component material. A p, -A' cross section of this mold is shown in FIG.

After fitting the masking plate 9 to the guide 8 of the mold,
At a low dose of 50 torr, the soft magnetic material powder was subjected to an Ar plasma flame with a current of 900 A and 8
Glazma spraying was applied under the output condition of 0KVA and the chip f1.
O was formed. A cross section taken along line B-B' is shown in FIG.

According to a separate experiment, under the above plasma spraying conditions, /lasma spraying 1.! Hit, about 3
It was confirmed that a soft magnetic material layer was formed with a film thickness of 0 μrn. In addition, the length of the plasma flame reaches approximately 50c1rL, and the speed at which it hits the object to be coated is close to that of Matsuha 2, and the general understanding of soft magnetic material powder is perfect, so it is possible to achieve high-density chips with a uniform composition. It is certain that 1+F(
It was done.

Next, the material was annealed using a trans-arc at a temperature of 800.degree. C. for 5 minutes, and then taken out of the furnace and the masking plate was removed. Then, the surfaces of the chips 7'' and 10 were precisely polished so that they were parallel to the upper surface 5' of the mold 5, and the respective chips 10a and 10b were removed from the mold. After that, the masking plate 6 was inserted and the gap formed was ground as a key part, and this gap was sealed with glass to form a magnetic head together with the coil, yoke, etc. Finally, a magnetic head for a VTR was obtained by polishing the sliding movement with the magnetic recording medium.

The sliding surface of the chip of the magnetic head manufactured by the above method has excellent magnetic circuit characteristics because its crystal grains are approximately 0.05 μm in size and the density of the chip is 100%. It was confirmed that there is.

In addition, when comparing its wear resistance with a conventional magnetic head made of Sendust alloy mounted on a KVTRK, it was found that compared to the conventional product, the wear resistance of the product of the present invention was about half that of the conventional product. It was reported that the improvement was more than double.

Example 2 Using a mold with the shape shown in Figure 6, a soft magnetic material with the same composition as in Example 1 was subjected to low-pressure plasma spraying under the same conditions, and a magnetic head was formed with near net Scheig growth. Formed.

In Fig. 6, the same parts as in Fig. 3 are given the same numbers (q). Also, Fig. 7 shows the CC/cross section of Fig.
FIG. 8 similarly shows the D-1)' cross section after plasma spraying treatment.

In Figure 6, a gap of 0.7 μm in thickness is added to the mold in which the chip portion forming the magnetic circuit is carved.
The sapphire plate 11 of m is inserted 7'1.

Using this mold, mL of thermal spraying was carried out under the same plasma melt side conditions as in Example 1, and then a magnetic head for a VTR was obtained in the same manner.

Regarding this magnetic head, the crystal grains, drop, magnetic circuit characteristics, and wear resistance were examined in the same manner as in Example 1. jEquivalent results were obtained.

Example 3 In Example 1, the soft magnetic material had an average particle size of 32
A chip was formed by a low-pressure plasma spray coating method using the same procedure except that a mixed powder of 81% by weight of nickel, 5.5mm% of molybdenum, and the balance iron having a mesh size of 5.5 mm (45 μm) was used. Manufactured the head.

The chip sliding surface of the magnetic head manufactured by the above method has crystal grains of 0.03 μm or less, and the chip density is 100%, so it has excellent magnetic circuit characteristics. was confirmed.

In addition, when its wear resistance was compared with a conventional magnetic head made of Sendust alloy using the same method as in Example 1, the wear resistance of the present invention product was about half that of the conventional product. It was confirmed that the product of the present invention is superior.

It was confirmed that a magnetic head manufactured by mechanically integrating the tooth profiles constituting the magnetic head after manufacturing them in the same manner as in the modified example had equivalent performance.

In addition, when a permalloy thread alloy is used as a chip profiteer, and a low-pressure plasma spraying method is applied to the permalloy thread alloy, the part including the sliding surface with the magnetic recording Qili body is formed of a soft magnetic material. It is possible to get a head.

〔Effect of the invention〕

According to the method of manufacturing a magnetic head of the present invention, a soft magnetic material, which has conventionally been difficult to use in manufacturing, is used.
It is possible to easily manufacture a large mouse magnetic head. Furthermore, it is possible to use a composition of the soft magnetic material that contains aluminum at a relatively high concentration and has optimal magnetic properties. Furthermore, by changing the polarity of the abrasive material to the opposite polarity during glass spray coating, it is possible to clean the abrasive spray surface (chip surface), and there is no need to supply 6it tt material after thermal spraying. By applying thermal spraying to the furnace side 1, l! l! It also has the advantage of being able to be constructed continuously.

The magnetic head manufactured by the manufacturing method of the present invention has good dimensional accuracy, excellent magnetic properties, and excellent wear resistance.

In addition, since the crystal grains are uniform and fine, the sliding surface with the magnetic recording medium does not become rough due to differences in wear ttj, which prevents phenomena such as chipping and "force warping" from occurring. It's something that doesn't exist.

[Brief explanation of the drawing]

Figure 1 &-1 is a conceptual diagram of the magnetic head, Figure 2 is a conceptual diagram of the mold in Example 1, and Figure 2 is a conceptual diagram of the surface of the Sendust alloy after puff polishing. Figure 3 A-A' sectional view, Figure 5 is low pressure) Figure 3 B-B'...1 side view after lasma spraying, Figure 6 is actual huL example 2.
Fig. 5 is a conceptual diagram of the mold, Fig. 7 is a c-c' cross-sectional view of Kasu Fig. 6, and Fig. 8 is a low-pressure, 7'' plasma welding part 1) of Fig. 6.
-1)' sectional view. 1 a, 1 b, 1 o-・-chip, 2-・
A-Y/, 3... Yoke, 4... Coil, 5...
- Rose, 5'...Mold top 11'll, 6.7...Aluminized cutting plate, 8...Id, 9...Mass 4 ring plate, 11...Sapphire plate.

Claims (3)

[Claims] (1) A method for manufacturing a magnetic head, which comprises forming at least a portion of a chip constituting the magnetic head, including a sliding surface with a recording medium, by applying a soft magnetic material using a low-pressure plasma spray coating method. (2) The soft magnetic material consists of 3 to 12% aluminum (i), 4 to 12% silicon (St), and the balance iron (Fe).
) A method for manufacturing a magnetic head according to claim 1. (3) Soft magnetic material strength/Nickel (Ni) 4o~8
The special i+! is composed of 5% Mo, 0 to 6% Mo, 0 to 7% Nb, and the balance chromium (Cr)! 1- A method of manufacturing a magnetic head according to claim 1.