JPS5827564B2 - magnetic head core - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic helad core made from a sendust-based high magnetic permeability alloy ribbon.

Conventionally, high permeability soft magnetic materials such as permalloy, ferrite, and ferrite chromium have been used as core materials for magnetic heads used in magnetic recorders and recorders, and these materials have also been used to suppress eddy current product. It is used in a laminated structure.

Furthermore, recently, sendust alloys, which have excellent magnetic properties and wear resistance as high magnetic permeability alloys, have been attracting attention as materials for laminated rad cores due to the development of thin ribbon technology.

However, this sendust alloy has a problem in that the magnetic temperature characteristics of magnetic permeability and coercive force are not uniform, and the temperature characteristics vary greatly depending on the composition.

Figure 1 shows the composition of various sendust alloy ribbons and their IKH.
z, shows temperature changes in effective magnetic permeability μeff and coercive force HC in direct current at 5m0e.

As shown in this figure, the temperature at which the magnetic permeability reaches its maximum and the coercive force reaches its minimum varies greatly depending on the composition.
For e・5.4Al・9.55S i, μeff=4X1.04. HC = 20 mOe, but it changes rapidly as the temperature rises, and at about 100°C μe
ff=3X103, HC=7'0m0e.

Therefore, when these sendust alloys are used alone, a core having stable characteristics due to temperature changes cannot be obtained.

The present invention solves such conventional problems, and provides a magnetic herad core in which magnetic temperature characteristics are flattened by laminating multiple types of sendust alloy ribbons having different compositions and composition ratios. Accordingly, the object of the present invention can be achieved.

The present invention will be explained in detail below based on examples and drawings.

Figure 2 shows the temperature characteristics of 85.02Fe shown in Figure 1, which has the maximum value of magnetic permeability and the minimum value of coercive force at a relatively low temperature.
・5.09A7 ・9.89S i Sendust ribbon core piece 1 and 85.01 with the temperature characteristics shown in Figure 1d, which have the maximum value of magnetic permeability and the minimum value of coercive force at a relatively high temperature.
This figure shows a head core formed by alternately laminating two kinds of Sendust ribbon core pieces 2 of F e 5.30AA 9.69Si.

The thickness of each ribbon core piece 1 shown in FIG.
~100 μm), and a total of 12 layers are laminated to form a core for one channel.

3 is an adhesive interposed between the ribbon core pieces 1.2.

The magnetic temperature characteristics of this core head are shown in Figure 3, and both the magnetic permeability and coercive force are flat compared to the temperature characteristics of each Sendust ribbon alone shown in Figures 1 and d. I understand.

Figure 4 shows three types of sendust ribbon core pieces 5 having the temperature characteristics shown in Figure 1 a, Figure 1 C, and Figure 1 e, respectively.
, 6.7 is alternately layered to form a head core,
In this core, as shown in FIG.
．． It can be seen that the temperature characteristics of No. 7 are averaged and have extremely flat temperature characteristics within the operating temperature range of 0° C. to 80° C.

Furthermore, by changing the number of laminated core pieces 5, 6, 7, and the thickness of each of the core pieces, a head core having even temperature characteristics with less temperature change can be produced.

Note that the thickness of the ribbon core pieces 5, 6, and 7 shown in FIG.
As shown in the figure, the thickness is about 40-100 μm, preferably 50 μm.

Here, the method for obtaining each Sendust ribbon core piece will be described. In the apparatus shown in FIG. 6, Sendust master alloy 9 is heated and melted in a heater 8 under an inert gas atmosphere such as Ar gas, and The molten material 9' is spouted from the nozzle 8a of the heater 8 between the twin rolls 10a and 10b rotating at high speed, and is rapidly rolled by the rolls 10a and 10b to obtain the ribbon 9'. “The core pieces are formed by pressing and etching.

For example, the nozzle 8a is 0.3 mmφ, and the roll 10a is
, 10b is made of chrome steel with a diameter of 65 mm and is 3000 rl) fi
When the Ar gas pressure in the heater 8 is raised to 1.5 atm and the molten material 9' is spouted between the rolls 10a and 10b, a thin strip 9'' with a thickness of about 50 μm and a width of about 5 mm is formed. Therefore, it is possible to form a core piece with a thickness of about 50 μm.

If the temperature at the time of ejecting the material is lowered as close to the melting point as possible, the degree of cooling during contact with the rolls can be made uniform, and microcracks on the surface of the ribbon due to thermal contraction will not occur.
A ribbon core piece with a smooth surface can be obtained.

As described above, the present invention aims to flatten the temperature characteristics by laminating multiple types of sendust alloy ribbons with different temperature characteristics, so that the core formed of a single sendust alloy In comparison, there is no change in characteristics due to temperature, and it has the advantage of providing stable performance.

Because it is a laminated layer of thin strips, the characteristics of each thin strip do not appear different compared to a laminated layer of thin strips cut from an alloy block, and the characteristics of each thin strip are effectively averaged. There are features that allow you to do this.

[Brief explanation of the drawing]

Fig. 1 is a magnetic temperature characteristic diagram of Sendust of various compositions, Fig. 2 is a cross-sectional view of an embodiment of the present invention, Fig. 3 is a temperature characteristic diagram of magnetic permeability and coercive force of the same as above, and Fig. 4 is a diagram of the present invention. FIG. 5 is a temperature characteristic diagram of magnetic permeability and coercive force, and FIG. 6 is a front view of an apparatus for manufacturing a Sendust alloy ribbon. 1.2... Thin strip core piece, 3... Adhesive, 5,6°7... Thin strip core piece, 8...
Heater, 8a... Nozzle, 9... Master alloy, 9'... Melting material, 9''... Thin strip, 10a, 10b... ···roll.

Claims (1)

[Claims] 1 Sendust-based high magnetic permeability alloy ribbon consisting of 4 to 7% aluminum, 8 to 11% silicon, and the balance iron, which are laminated with a plurality of types having different temperature characteristics of magnetic permeability,
A magnetic head core is characterized in that the temperature characteristics of the average magnetic permeability are flat within the operating temperature range.