DE2018973A1 - Method for orienting the direction of magnetization of a magnetic layer carried by a cylindrical support and apparatus for carrying out the method - Google Patents

Description

Method of orienting the direction of magnetization one of a cylindrical Supporting magnetic layer and device for carrying out the method

It is known that it is possible, with a cylindrical base serving as a conductor, for example a wire, applied magnetic layer to orient the direction of permanent magnetization of this perpendicular to the axis (in the circumferential direction) of the layer arranged layer by passing an electric current through the latter. The current flowing through the support generates a magnetic field running in the circumferential direction on the surface of the support and the magnetic layer is given an anisotropy with a circumferential orientation, d. H. that its steady direction of magnetization or the direction of "easy magnetization" is circular and coaxial

009845/1344

to the document is. This circumferential orientation method is limited, in particular due to the Heating of the base and, in the case where the magnetic layer is deposited by electrolysis, and the base serves as an electrode, due to the permissible voltage drop along the base. Becomes a composition through electrolysis made of iron and nickel on a wire made of copper on beryllium with a diameter of 125 / tab-deposited, then the orientation field is limited to a few 10 oersted, which is insufficient for a good orientation of the magnetization is. Furthermore, the maximum possible value of the orientation field is the smaller the smaller the diameter of the wire.

It is also known for the axial orientation of such a magnetic layer on its base by means of a magnetic one or electromagnetic device outside the pad, for example by a solenoid, an orientation field to generate in the magnetic layer, which runs parallel to the axis of the base.

The invention relates to a method which makes it possible to determine the direction of permanent magnetization of one of a cylindrical base supported magnetic layer in the circumferential direction to orientate and avoid the disadvantages of the known method.

According to the invention the method is for circumferential running orientation of the direction of permanent magnetization of a supported by a cylindrical base Magnetic layer characterized in that the magnetic layer is exposed to a magnetic field which is perpendicular to the Axis of the pad is aligned and rotates about this axis, the magnetic field from an outside of the wire Device is generated.

0 0 98 45 / 134A

The rotating magnetic field is preferably generated by an arrangement of flat coils, the planes of which run parallel to the cylindrical base and those of multiphase coils Streams are flowed through.

The arrangement can comprise η coils, through whose levels the Wire passes through it, wherein in each case the angle between two adjacent coils is 1Γ / n and the coils of Currents hit η phases are traversed.

The arrangement preferably comprises 2 m coils, two of which each run parallel to one another and which are evenly around are arranged around the wire, wherein two parallel coils are traversed by a current of the same phase, while the parallel pairs of coils are traversed by currents with m phases. It is particularly easy and beneficial when η = m - 2.

In an advantageous embodiment, each of the coils forms a rectangular shape and has two sides parallel to the cylindrical base.

The following description of the accompanying drawings illustrates how the invention can be implemented.

Figures 1 and 2 show a coil arrangement for carrying out the method according to the invention.

FIG. 3 schematically illustrates the principle of the method according to the invention.

The device shown in Figure 1 comprises an electrolysis tank 1, for example, an electrolyte on the base of iron and nickel. The copper wire 2 travels continuously through this container from one side to the other

009848/13 ^ 4

and is covered with a magnetic layer 3 during its passage through the container.

Around the direction of magnetization of the layer 3 in the circumferential direction To orientate, the container is surrounded by two coils 4 and 5, the shape of which is rectangular and through which Levels of wire 2 wanders. Furthermore, the planes of the coils are perpendicular to each other and they are over their terminals 6, 7 and 8, 9 fed by two-phase currents.

The device according to FIG. 2 likewise comprises an electrolysis tank 1 through which the wire 2 migrates. This container is rectangular by four coils 10 to 13 Surround shape whose planes are parallel to the wire 2. The planes of the coils IO and 12 are the same as those the coils 11 and 13 parallel to each other. Furthermore, the planes of the coils IO and 12 are perpendicular to those of the coils 11 and 13 are arranged.

The coils 10 and 12 are fed via the terminals 14 and 15, while the coils 11 and 13 together via the terminals 16 and 17 are fed. The terminals in turn are fed by two-phase currents.

The magnetic field H generated by the coils 4 and 5 or the coils 10 to 13 is a field which is perpendicular is directed to the wire 2 and rotates around it.

At a given point in time (see FIG. 3) the field H has a direction D and consequently the layer orients itself circumferentially during the precipitation according to the direction of saturation d, except at the points where the projection of the field H onto the tangent plane of the wire 2 is weak and where a north pole N and a south pole S occur.

0098A5 / 13U

Since the field Ϊ? turns around the wire 2 changes the location of the magnetic poles N and S is constant. Therefore, the magnetic layer 3 is properly oriented at every point on its circumference.

Research has shown that the state of the magnetic If field is of sufficient size (at least equal to 10 Oersted) and that the frequency of the currents generating the field should be of the order of 50 Hz. The angular Scatter of the material of layer 3 is lower than 0 ° 2 for a precipitation duration of a few 10 seconds.

The method according to the invention avoids an ohmic one Loss in the cylindrical base 2, as it would produce an orientation current. Under these conditions is the electrical potential represented by the wire 2 in the electrolysis tank 1 where the magnetic precipitation is effected the same at every point on the wire, which is essential to ensure a homogeneous distribution of the current on the wire 2 along the container.

This enables the use of electrolytes in which the composition of the precipitate is dependent on the current density, without an inhomogeneity of the composition in the Ä

Layer thickness of the final magnetic deposit occur would.

The wire 2 is traversed by the electrolysis equilibrium during the orientation of the magnetic layer and is therefore subjected to a force which acts perpendicular to the wire, resulting from the alternating magnetic field Ί? and the superimposed direct current. Consequently, if the wire is subjected to mechanical tension, it will vibrate under the action of this force, which disturbs the deposition of the magnetic layer.

00 9 8 45/13

To remedy this drawback, it is possible to reduce the span of the wire inside the container 1 or a device zn use, which makes it possible to pull the wire at a very low mechanical stress through the container. Such a device is described in French patent application PV no. 6910210 of April 3, 1969 by the applicant.

Although the method to orient the direction of the permanent Magnetization of a magnetic layer has been described on the basis of a layer which is applied by means of electrolysis, it is obvious that the method is also carried out can be used for layers which are applied by other means or which are already on a base are upset.

The type of implementation as described can also be modified, in particular by replacing equivalents technical means without departing from the scope of the present invention.

009845/13 44

Claims (8)

Pa t e η t ans ρrttche Method for circumferential orientation of the direction the permanent magnetization one of a cylindrical Supported magnetic layer, characterized by the fact that one leans the layer Exposing a magnetic field which is oriented perpendicular to the axis of the base and rotates around this axis, wherein this magnetic field is generated by a device outside the wire. 2. Device for circumferential orientation of the direction the permanent magnetization of one of a cylindri- " see underlay worn magnetic layer, thereby gekennze lehne t that it comprises an arrangement of flat coils (4 * 5), the planes of which are parallel to cylindrical base (2) are arranged and through multiphase currents are traversed, the arrangement a magnetic field is generated which is directed at right angles to the axis of the base and rotates around this axis turns. 3. Device for the circumferential orientation of the direction of permanent magnetization of a magnetic layer during application on a cylindrical base which continuously traverses an electrolysis container, characterized in that it has a coil arrangement which is arranged on the outside of the container (1) and surrounds it, wherein the planes of the flat coils {4L, Sj are arranged parallel to the cylindrical base (2) and are traversed by multiphase currents and the arrangement generates a magnetic field which is oriented at right angles to the axis of the base and rotates around this axis. 009845/1344 4. Apparatus according to claim 2 or 3, characterized g e identifier I think that the arrangement comprises η coils (4, 5), through the planes of which the wire (2) wanders, two adjacent coils each enclose the angle 1t / n and currents with η phases flow through these coils will. 5. Apparatus according to claim 2 or 3, characterized in that that the arrangement has 2 m coils (10, 11, 12, 13), of which two to each other are parallel, which are arranged regularly around the wire (2), with two parallel coils (10, 12) (11, 13) are traversed by a current of the same phase, while the parallel coil pairs of Currents with m phases are traversed. 6. Device according to claim 4, characterized in that that the arrangement comprises two flat coils (4, 5), the planes of which are perpendicular to each other and through which two-phase currents flow. 7. Apparatus according to claim 5, characterized Ichnet that the arrangement has four coils (10, 11, 12, 13), two of which are parallel to each other are and which surround the wire (2), two parallel coils (10, 12), (11, 13) from a current of the same Phase while the two pairs of parallel Two-phase currents flow through coils. 8. Apparatus according to claim 2 to 7, characterized in that that each coil has a rectangular shape and two sides parallel to the cylindrical Underlay run. 009845/1 3U