JPH02172004A - Magnetic head having excellent wear resistance and production thereof - Google Patents

Abstract

PURPOSE:To improve wear resistance by forming a magnetic head core from the laminate of core chips formed by subjecting Cr-contg. 'Permalloy(R)' to a nitriding treatment. CONSTITUTION:The core chips 1 consisting of the Cr-contg. 'Permalloy(R)' are annealed for >=15 minutes at 900 to 1,200 deg.C in an atmosphere consisting of >=5% nitrogen and the balance hydrogen to form cured layers 3 by the nitriding treatment. Such core chips are laminated via adhesive layers 4 to form the head core 4. The sliding surface 2 has the state disposed with the hardened layers 3 at equal intervals in the core. The wear resistance is thus improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to an improvement in the wear resistance of a permalloy magnetic head and a method for manufacturing the improved magnetic head (core).

C. Conventional technology and problems] Typical materials for general-purpose magnetic heads (cores) include:
There are four types: permalloy, ferrite, sendust, and amorphous. Each of these has the following characteristics.

(a) Permalloy has high magnetic permeability and saturation magnetic flux density, and has good cold workability, but has the disadvantage of high wear due to tape sliding.

(b) Since ferrite has a high electrical resistance, it has excellent characteristics at high frequencies, but it has the disadvantage of a low saturation magnetic flux density.

(8) Sendust has high magnetic permeability and saturation magnetic flux density, and wear caused by sliding of the tape is small; however, it has the drawback of extremely poor cold workability.

(d) Amorphous magnetic permeability is high and wear is low, but since only extremely thin materials can be manufactured, the lamination process takes too much time and costs, resulting in a significant increase in cost.

Among these materials, the most widely used material is mainly permalloy, and in particular, permalloy is mostly used for the magnetic heads (cores) of audio tape recorders. The only drawback of permalloy is that it has poor wear resistance, but in order to improve this, it has been proposed to add wear resistance improving elements such as Nb.

However, such additive elements have the disadvantage that they are very expensive and that cold workability is significantly deteriorated by adding them.Additionally, even with the addition of such additive elements, the wear resistance of permalloy still cannot be improved. The big problem was that it wasn't improving enough.

[Structure of the invention]

Therefore, the present inventor focused on the point of laminating and incorporating several permalloy thin plates in the manufacturing process of the magnetic head (core), and created a magnetic head and a magnetic head with improved wear resistance by hardening the laminated layers. This method was invented.

That is, the present invention provides a magnetic head with excellent wear resistance including a magnetic head core formed from a laminate of core chips nitrided with Cr-containing permalloy, and a core chip for a magnetic head made of Cr-containing permalloy. A magnetic head with excellent wear resistance, characterized in that the magnetic head is annealed at a temperature of 900°C to 1200°C for 15 minutes or more in an atmosphere consisting of 5% by volume or more of nitrogen and the balance is hydrogen, and is further laminated to form a magnetic head core. The present invention provides a method for manufacturing.

[Detailed description of the invention]

In order to facilitate understanding of the present invention, the present invention will be described in detail below.

Permalloy magnetic head cores are usually 0.1 m thick to reduce eddy current loss and ensure good high frequency characteristics.
It uses six laminated thin plates. Therefore, as shown in Fig. 1, by forming a hardened layer on the surface of the core chip 1 by nitriding and then laminating this layer, five hardened layers 3 are arranged at equal intervals on both sides of the core and inside the core. It becomes a state. For this reason, as shown in Figure 1, even when the tape slides (the tape runs perpendicular to the plane of the paper in Figure 1), the hardened layer has excellent abrasion resistance, making the core as a whole resistant to wear. performance is greatly improved.

In order to form a hardened layer by nitriding, a nitriding component must be included as a permalloy component, and in this respect, Cr-permalloy is used as the permalloy for the magnetic head core in the present invention. The components of Cr-permalloy are as follows.

Ni: 9 to 82%, Cr: 3 to 6%, Fe: remainder (contains inevitable impurities) Next, from the viewpoint of manufacturing cost, it is desirable that the nitriding treatment also serves as magnetic annealing, and the conditions are as follows. Limited for a reason.

If the nitrogen content in the annealing atmosphere is less than 5% by volume, nitriding will be difficult to proceed and wear resistance will be insufficient.
That's all. There is no particular problem even if the nitrogen content is 100% by volume.

If the annealing temperature is less than 900°C, good magnetic properties cannot be obtained, and if it exceeds 1200°C, it is not practical for an actual industrial furnace, so the annealing temperature was set to 900°C or more and 1200°C or less.

If the time is less than 15 minutes, good magnetic properties and sufficient wear resistance cannot be obtained, so the time is set to 15 minutes or more.

There is no particular upper limit to the time, but if it is too long, the cost will increase, and if nitriding progresses too much, the magnetic properties will deteriorate, so 4 hours or less is usually appropriate.

The core chip 1 that has undergone the nitriding process is adhered as shown in FIG. 2 using an appropriate adhesive 4 such as an epoxy adhesive.

Next, the present invention will be explained based on examples.

〔Example〕

As a permalloy material, Cr-permalloy (81% Ni
-4%Cr-remaining Fe), the plate thickness is finally 0 by cold rolling.
．． Finished into a 1 nn thin plate. This was punched out into a core chip of a predetermined shape using a press.

Next, this far chip was annealed under the conditions shown in Table 1 (Nos. 1 to 4 were nitrided at the same time), and then incorporated into a magnetic head, and the tape running surface was finally polished. The magnetic head thus produced was actually installed in a tape recorder, and a tape running test was conducted.

The tape running test was carried out for 1,000 hours at a room temperature of 20° C. and a humidity of 50%, using a standard type tape and replacing it with a new one every 200 hours. Thereafter, the amount of wear on the magnetic head core was measured using a surface profile measuring device. head core
The maximum wear amount is shown in Table 1.

Table 1 Na 1 to 4 in Table 1 are examples of the present invention, and although the material is Cr-permalloy, which does not have very good wear resistance, it is significantly more effective than Cr-permalloy, which is not nitrided in comparative example Nα5. It can be seen that the amount of wear is reduced and the wear resistance is improved.

Note that, depending on the nitriding treatment conditions, the magnetic properties of the heads were slightly inferior in some cases, but this was not at a level that would pose a practical problem.

[Effects of the present invention]

As described above, according to the present invention, it is possible to obtain a magnetic head with extremely excellent wear resistance, which has extremely high practical value and can greatly contribute to the advancement of technology and electronic equipment.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a magnetic head (core), and FIG. 2 is a partially enlarged view of FIG. 1. A: Enlarged part 1: Core chip 2: Tape sliding surface 3: Hardened layer by nitriding 4: Adhesive layer 1

Claims (2)

[Claims] (1) A magnetic head with excellent wear resistance, including a magnetic head core formed from a laminate of core chips made of nitrided Cr-containing permalloy. (2) A core chip for a magnetic head made of Cr-containing permalloy is prepared, and the core chip is heated at a temperature of 900°C to 12% by volume of nitrogen or more in an atmosphere with the balance being hydrogen.
A method for manufacturing a magnetic head with excellent wear resistance, characterized by annealing at 00° C. for 15 minutes or more and then laminating the same to form a magnetic head core.