DE102019133826A1 - Tape for a magnetic field sensitive component - Google Patents

Abstract

Tape for a magnetic field sensitive component, the tape consisting of a soft magnetic alloy and a coating of metal oxide.

Description

background

Current transformers are used to measure low direct currents. So far it has been difficult to use toroidal cores as current transformers, as they were previously too low-permeability at high frequencies (e.g. 100 kHz). Measures were also known to use toroidal cores when measuring low direct currents, but these measures are technically complex and it was not possible to carry out a measurement process with these toroidal cores that was stable over decades.

The present invention is based on the object of solving the above-mentioned problems.

Summary

1. a. Bestehend aus einer weichmagnetische Legierung auf Fe-Basis mit der Zusammensetzung der allgemeinen Formel: [Fe_1-aM_a]_100-x-y-z-αCu_xSi_yB_zM'_α, worin M Co und / oder Ni ist, M' mindestens ein Element ist, ausgewählt aus der Gruppe bestehend aus Nb, W, Ta, Zr, Hf, Ti und Mo und a, x, y, z und α erfüllen jeweils 0 ≤ α < 0,5, 0,1 ≤ x ≤ 3, 0 ≤ y ≤ 30, 0 ≤ z ≤ 25, 5 ≤ y + z ≤ 30 und 0,1 ≤ α ≤ 30, wobei mindestens 50% der Legierungsstruktur von feinen kristallinen Partikeln besetzt sind; und
2. b. mit einer Beschichtung aus MgO.

The solution to this problem is defined in the appended claims. In particular, the invention is directed to a tape for a magnetic field-sensitive component, such as a toroidal core, the tape

1. a. Consisting of a soft magnetic Fe-based alloy with the composition of the general formula: [Fe _1-a M _a ] _100-xyz-α Cu _x Si _y B _z M ' _α , where M is Co and / or Ni, M' is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo and a, x, y, z and α each satisfy 0 α <0.5, 0.1 x 3, 0 y 30, 0 z 25, 5 y + z 30 and 0.1 α 30, with at least 50% of the alloy structure being occupied by fine crystalline particles; and
2. b. with a coating of MgO.

It was surprisingly found that a tape with this coating, when used in toroidal cores at high frequencies, leads to an increased inductance of these toroidal cores compared to uncoated variants.

A method of making this tape is also disclosed.

This method has the advantage that it does not require the use of organic solvents when applying the coating. An aqueous solution for applying the layer is sufficient to obtain the coated tape, which is advantageous for aspects of workplace safety and environmental protection.

Figure list

• 1 shows the cross section of a ribbon 1 according to the invention with a metal oxide coating 2 on top and an optional electrically insulating layer 3rd on the bottom.
• 2 shows the inductance of toroidal cores made from tape coated with metal oxide according to the invention (upper graph, - -) and of toroidal cores made from conventional uncoated tape (lower graph, - - - -). The X-axis shows the core number and the Y-axis shows the induction constant AL in µH with a number of turns of 1.

In-depth description

Disclosed is a tape for a magnetic field-sensitive component, such as a ring magnet, made of a soft magnetic Fe-based alloy and a coating of a metal oxide.

The metal oxide is preferably MgO.

The Fe-based soft magnetic alloy has a composition according to the general formula: [Fe1-aMa] 100-xyz-aCuxSiyBzM'α, wherein M is Co and / or Ni, M 'is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo and a, x, y, z and α satisfy 0 a <0.5, 0.1 x 3, 0 y 30, 0 z, respectively 25, 5 y + z 30 and 0.1 α <30, with at least 50% of the alloy structure being occupied by fine crystalline particles.

$$\mathrm{0,1}\le \text{x}\le \text{3}$$

$$6\le \text{y}\le \text{25}$$

$$2\le \text{z}\le \text{25}$$

$$14\le \text{y}+\text{z}\le \text{30}$$

$$\mathrm{0,1}\le \mathrm{\alpha }\le \mathrm{10;}$$

$$0\le \text{a}\le \text{0}\text{,1}$$

$$\mathrm{0,5}\le \text{x}\le 2$$

$$10\le \text{y}\le \text{25}$$

$$3\le \text{z}\le \text{18}$$

$$18\le \text{y}+\text{z}\le \text{28}$$

$$2\le \mathrm{\alpha }\le \mathrm{8;}$$

oder $$0\le \text{a}\le \text{0}\text{,05}$$

$$\mathrm{0,5}\le \text{x}\le 2$$

$$11\le \text{y}\le \text{24}$$

$$3\le \text{z}\le \text{9}$$

$$18\le \text{y}+\text{z}\le \text{27}$$

$$2\le \mathrm{\alpha }\le 8$$

sein;The areas can $$0\le \text{a}\le 0.1$$

$$0.1\le \text{x}\le \text{3rd}$$

$$\mathrm{6th}\le \text{y}\le \text{25th}$$

$$2\le \text{z}\le \text{25th}$$

$$\mathrm{14th}\le \text{y}+\text{z}\le \text{30th}$$

$$0.1\le \mathrm{\alpha }\le \mathrm{10;}$$

$$0\le \text{a}\le \text{0}\text{,1}$$

$$0.5\le \text{x}\le 2$$

$$10\le \text{y}\le \text{25th}$$

$$\mathrm{3rd}\le \text{z}\le \text{18th}$$

$$\mathrm{18th}\le \text{y}+\text{z}\le \text{28}$$

$$2\le \mathrm{\alpha }\le \mathrm{8th;}$$

or $$0\le \text{a}\le \text{0}\text{, 05}$$

$$0.5\le \text{x}\le 2$$

$$11\le \text{y}\le \text{24}$$

$$\mathrm{3rd}\le \text{z}\le \text{9}$$

$$\mathrm{18th}\le \text{y}+\text{z}\le \text{27}$$

$$2\le \mathrm{\alpha }\le \mathrm{8th}$$

be;

The composition may be Fe _100-xyz-α Nb _α Cu _x Si _y B _z , where x, y, z and α each 0.5 x 2, 14 y 18, 4 z 10 y + z ≤ 25 and 1 ≤ α ≤ 6.

The composition may be Fe _100-xyz-α Nb _α Cu _x Si _y B _z , where x, y, z and α are each 1 x 2, 15 y 16, 6 z 8 8 y y + z, respectively 23 and 2 ≤ α ≤ 4.

The composition can preferably be Fe _73.5 Cu ₁ Nb ₃ Si _15.5 B ₇ .

The Fe-based soft magnetic alloy having the above composition has an alloy structure at least 50% of which is composed of fine crystalline particles. These crystalline particles are based on α-Fe having a bcc structure in which Si and B, etc. are dissolved. These crystalline particles have an extremely small average particle size of 1000 Å or less and are evenly distributed in the alloy structure. Incidentally, the average particle size of the crystalline particles is determined by measuring the maximum size of each particle and averaging them. It is preferably 500 Å or less, more preferably 200 Å or less, and particularly 50-200 Å.

The remaining part of the alloy structure except for the fine crystalline particles is mainly amorphous. Even when fine crystalline particles occupy substantially 100% of the alloy structure, the Fe-based soft magnetic alloy of the present invention has sufficiently good magnetic properties.

Incidentally, with regard to inevitable impurities such as N, O, S, etc., it should be noted that their inclusion in such amounts as not to deteriorate the desired properties is not considered suitable for changing the alloy composition of the present invention for magnetic cores, etc.

Next, the method for producing the Fe-based soft magnetic alloy of the present invention will be explained in detail below.

First, a melt of the above composition is rapidly quenched by known liquid quenching methods such as a single roll method, a double roll method, etc. to form amorphous alloy ribbons. Usually, amorphous alloy ribbons made by the single roll method, etc. have a thickness of about 5 to 100 µm, and those having a thickness of 25 µm or less are particularly suitable as magnetic core materials for use at high frequency.

These amorphous alloys may contain crystal phases, but the alloy structure is preferably amorphous in order to ensure the formation of uniform fine crystalline particles by a subsequent heat treatment. Incidentally, the alloy of the present invention can be produced directly by the liquid quenching method without resorting to heat treatment, as long as suitable conditions are selected.

A band is understood here to be any metallic product in which the length expansion is substantially greater than the width and thickness expansion (preferably at least 10 times, 100 times or 1000 times).

The cross-section of the tape can be circular, trapezoidal, rectangular or square, in which case the corners can be rounded.

How out 1 the band can be seen to have a top and a bottom. The top or bottom can extend up to the middle of the circumference, that is, the side surfaces are added approximately halfway to the top or bottom. The tape is preferably of rectangular cross-section, the width of the Tape is greater than the thickness of the tape, e.g. at least 2, 4, 6, 8, 10 times as large.

The width of the tape can be 0.5-12.5 mm, 1-7.5 mm, or 2-6 mm.

The thickness of the tape can be 1-100 µm, 2-50 µm, 15-20 µm, 18-22 µm, 3-10 µm, or 4-6 µm.

The metal oxide coating can only be on the top of the tape. The thickness of the coating on the top can be 5-15%, 7.5-12.5%, or 9-11% of the thickness of the tape. For example, the thickness of the coating can be 0.5-4 µm, 0.75-3 µm, 0.9-2.1 µm.

The underside of the tape can be coated or uncoated. If there is a coating on the underside, it can be designed to be electrically insulating. In particular, an electrically insulating layer can be provided on the underside. The thickness of the coating on the lower side is preferably smaller than the coating on the upper side and can be 0-1%, 0.001-0.5%, or 0.01-0.05% of the thickness of the coating on the upper side. All known electrically insulating materials that are used in the construction of core magnets and that remain stable at temperatures of over 600 ° C are suitable as a coating on the underside. For example, the coating can be a metal oxide (e.g. aluminum oxide, calcium oxide, MgO).

A magnetic field sensitive component comprising the tape described above is also disclosed. The magnetically sensitive component can be a toroidal core, block (can be produced from laterally flattened toroidal core, which consists of straight connecting pieces and connecting curved connecting sections, in which the curved connecting sections have been removed so that the straight connecting pieces remain), or a cut tape core.

The toroidal core can comprise the tape described above. The toroidal core surrounds the tape in turns. The toroidal core can be made from the tape in any of the usual ways.

The dimensions of the toroidal core depend on the area of application and are not specifically defined. The outer diameter can be 10-400mm, 20-90mm, 30-80mm, 35-70mm, 35-45mm. The inner diameter can accordingly be 5-50%, 10-45%, or 10-20%, 17-30 of the outer diameter. The thickness of the ring core can be 5-50 mm, 10-40 mm, or 20-30 mm.

The toroidal core can also be incorporated into a device or material for protection against mechanical damage. The toroidal core can therefore have an externally applied lacquer layer or coating made of epoxy powder. Furthermore, the toroidal core can also be present in a housing (such as a protective trough), which can be made from an electrically insulating plastic, for example.

The magnetically sensitive component, in particular the toroidal core according to the invention, is particularly suitable for use in devices for measuring a differential current.

Therefore, a device for the galvanically separated measurement of a differential current is also disclosed which comprises a magnetic field sensitive component according to the invention.

• Messen des Magnetfeldes von aktiven Leitern, die als Primärwicklung durch das magnetfeldempfindliche Bauelement geführt werden;
• Bestimmen, ob der Stromflusses in einer Sekundärwicklung, die über das magnetempfindliche Bauteil gekoppelt ist, einem vorbestimmten Kriterium entspricht;
• Ausgeben einer Meldung über das Vorhandensein eines Differenzstromes.

Correspondingly, a method for electrically isolated measurement of a differential current with a magnetic field sensitive component according to the invention is also disclosed, which comprises:

• Measuring the magnetic field of active conductors which are guided as a primary winding through the magnetic field sensitive component;
• Determining whether the current flow in a secondary winding which is coupled via the magnetically sensitive component corresponds to a predetermined criterion;
• Output of a message about the presence of a differential current.

1. a. Bereitstellen eines Bandes aus einer weichmagnetische Legierung auf Fe-Basis mit der Zusammensetzung der allgemeinen Formel: [Fe_1-aM_a] _100-xyz-αCu_xSi_yB_zM'_α, worin M Co und / oder Ni ist, M' mindestens ein Element ist, ausgewählt aus der Gruppe bestehend aus Nb, W, Ta, Zr, Hf, Ti und Mo und a, x, y, z und α erfüllen jeweils 0 ≤ a ≤ 0,5, 0,1 ≤ x ≤ 3, 0 ≤ y ≤ 30, 0 ≤ z ≤ 25, 5 ≤ y + z ≤ 30 und 0,1 ≤ α < 30, wobei mindestens 50% der Legierungsstruktur von feinen kristallinen Partikeln besetzt sind;
2. b. Beschichten des Bandes mit MgO.

A method for producing a tape according to the invention is also disclosed, comprising:

1. a. Providing a strip of a soft magnetic Fe-based alloy with the composition of the general formula: [Fe _1-a M _a ] _100-xyz-α Cu _x Si _y B _z M ' _α , in which M is Co and / or Ni, M 'is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo and a, x, y, z and α satisfy 0 a 0.5, 0.1, respectively x 3, 0 y 30, 0 z 25, 5 y + z 30 and 0.1 α <30, with at least 50% of the alloy structure being occupied by fine crystalline particles;
2. b. Coating the tape with MgO.

• Benetzen des Bandes in einer wässrigen Lösung umfassend MgO;
• Trocknen des Bandes bis zur Ausbildung einer Beschichtung von MgO auf dem Band.

Furthermore, step b can comprise the steps:

• Wetting the tape in an aqueous solution comprising MgO;
• Drying the tape until a coating of MgO is formed on the tape.

The aqueous solution contains 5-15, 7.5-12.5, or 9-11% by weight (w / w) MgO.

The MgO used for the solution can have a grain size of 0.01 µm-2 µm, 0.5 µm-2 µm, or 1-2 µm. The MgO does not go into solution in water.

The aqueous solution can furthermore contain an adhesive which is soluble in aqueous solution. The proportion of adhesive in the aqueous solution is 1-10, 2.5-7.5, or 4-6% by weight (w / w). The adhesive can be an organic adhesive. The organic adhesive can comprise starch or cellulose ether. The adhesive can promote adhesion of the metal oxide to the tape. After the tape has been wound up to form a magnetically sensitive component, the metal oxide is fixed by the wound tape itself and can therefore be removed by the action of heat. This can further improve the inductance of the magnetically sensitive component.

• Benetzen des Bandes in einer wässrigen Lösung umfassend MgO;
• Entfernen der wässrigen Lösung umfassend MgO auf der Unterseite des Bandes; und Trocknen des Bandes bis zur Ausbildung einer Beschichtung von MgO auf dem Band.

Step b of the method according to the invention can furthermore comprise:

• Wetting the tape in an aqueous solution comprising MgO;
• Removing the aqueous solution comprising MgO on the underside of the tape; and drying the tape until a coating of MgO is formed on the tape.

• Benetzen des Bandes in einer wässrigen Lösung umfassend MgO;
• Entfernen der wässrigen Lösung umfassend MgO auf der Unterseite des Bandes;
• Auftragen einer Isolationsschicht auf der Unterseite des Bandes;
• Trocknen des Bandes bis zur Ausbildung einer wasserfreien Beschichtung von MgO auf der Oberseite des Bandes und der Isolationsschicht auf der Unterseite des Bandes.

Step b of the method according to the invention can furthermore comprise at least one, preferably all of the following steps:

• Wetting the tape in an aqueous solution comprising MgO;
• Removing the aqueous solution comprising MgO on the underside of the tape;
• Applying a layer of insulation to the underside of the tape;
• Drying the tape until an anhydrous coating of MgO is formed on the top of the tape and the insulation layer on the bottom of the tape.

The step of wetting the tape can have a duration of 1-10 minutes, 2-8 minutes, 3-5 minutes.

The step of drying the tape can have a duration of 1-10 min, 2-8 min, 3-5 min and at one

The steps of wetting, removing and applying an insulation layer are carried out at around room temperature, i.e. in the temperature range of 20 ° C-27 ° C, 21 ° C-25 ° C, or 22-23 ° C.

The drying step can be carried out in a temperature range of 180 ° C-220 ° C, 190 ° C-210 ° C, or 195 ° C-205 ° C. Drying can be carried out at a temperature and time which will cause an adhesive to evaporate from the solution with which the tape was wetted.

After cooling to room temperature, the tape can be wound into a magnetically sensitive component with turns, e.g. a toroidal core, using known processes.

Thereafter, the magnetically sensitive components obtained with windings, e.g. toroidal cores, can be treated in a magnet furnace, the toroidal core being treated at a target temperature in the presence of a magnetic field.

The target temperature can be 580 ° C-620 ° C, 590 ° C-610 ° C, or 595 ° C-605 ° C.

The heating rate or cooling rate can be 3 ° C-7 ° C / min or 4 ° C-6 ° C / min.

During the treatment in the magnetic furnace, a magnetic field with 1800 A / cm -2200 A / cm, 1900 A / cm-2100 A / cm or 1950 A / cm-2050 A / cm can be used (e.g. at right angles to the magnetic path).

However, it is also possible to treat the magnetically sensitive components with windings obtained, e.g. toroidal cores, initially only in an oven without exposure to a magnetic field, whereby the temperature conditions correspond to those for magnetic ovens above.

Examples

Example 1: Manufacture

tape 1 from a finely crystalline iron-based alloy with proportions of Fe _73.5 Cu ₁ Nb ₃ Si _15.5 B ₇ with a thickness of 20 microns and a width of 5 mm are at room temperature (approx. 22 ° C) in an aqueous immersion bath containing 10 wt .-% MgO (grain size smaller than 2 µm) and an organic adhesive ( 5 Weight% (w / w)) introduced in the run.

Then the wetted tape 1 taken from the immersion bath and pulled through two rubber rollers on the underside 5 remove the solution from the tape

The tape is then dried continuously at approx. 200 ° C for approx. 5 minutes, so that a dry MgO coating 2 on the top 4th arises.

The coated tape obtained 1 is wound into a core with an outer diameter of approx. 20 mm and an inner diameter of 15 mm, in order to obtain a toroidal core.

The toroidal cores obtained are then treated in a magnet furnace as follows: The heating rate, starting from room temperature, is 5 ° C./min until a temperature of approx. 600 ° C. is reached, followed by cooling at 5 ° C./min to room temperature. During this treatment, the toroidal cores will be exposed to a magnetic field of 2000 A / cm at right angles to the magnetic path.

• 25 gemäß dem Verfahren aus Beispiel 1 hergestellte Ringkerne wurden mit 25 Ringkernen verglichen, der im Prinzip nach dem gleichen Herstellungsverfahren wie in Beispiel 1 hergestellt wurden, bei dem aber die wässrige Lösung kein MgO enthielt. Die Induktivität jedes Kerns wurde bestimmt. In 1 sind die Induktivitätskonstanten der Ringkerne dargestellt, wobei die Kerne gemäß aufsteigender gemessener Induktivität in der X-Achse geordnet wurden.

Example 2: Measuring the inductance

• 25 toroidal cores produced according to the process from example 1 were compared with 25 toroidal cores which were produced in principle according to the same production process as in example 1, but in which the aqueous solution did not contain any MgO. The inductance of each core was determined. In 1 the inductance constants of the toroidal cores are shown, the cores being arranged according to ascending measured inductance in the X-axis.

How out 1 can be seen, the induction constant at 100 kHz for cores from the coated strip is on average higher than for the cores from the comparative example.

It was therefore possible, surprisingly, to show that an MgO coating substantially improves the inductance of the iron alloy.

List of reference symbols

1

Tape or soft magnetic alloy

2

Coating with metal oxide on top

3

Optional electrically insulating coating on the underside

4th

Top

5

bottom

Claims (14)

Tape (1) for a magnetic field-sensitive component, the tape (1) a. consisting of a soft magnetic Fe-based alloy with the composition of the general formula: [Fe _1-a M _a ] _100-xyz-α Cu _x Si _y B _z M ' _a , where M is Co and / or Ni, M' is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo and a, x, y, z and α satisfy 0 a 0.5, 0.1 x, respectively 3, 0 y 30, 0 z 25, 5 y + z 30 and 0.1 α <30, with at least 50% of the alloy structure being occupied by fine crystalline particles; and b. with a coating (2) made of MgO. Volume (1) according to Claim 1 wherein the coating (2) is only on the upper side (4) of the belt. Volume (1) according to Claim 2 , wherein on the underside (5) of the tape (1) is an electrically insulating layer (3). Belt (1) according to one of the preceding claims, wherein the thickness of the coating (2) made of MgO on the upper side (4) is 5-15%, 7.5-12.5%, or 9-11%> the thickness of the belt (1) is. The tape (1) according to any one of the preceding claims, wherein the composition is Fe _100-xyz-α Nb _α Cu _x Si _y B _z , wherein x, y, z and α each 0.5 x 2, 14 y 18, 4 ≤ z ≤ 10 ≤ y + z ≤ 20 and 1 ≤ α ≤ 6. Belt (1) according to one of the preceding claims, wherein the composition is Fe _73.5 Cu ₁ Nb ₃ Si _15.5 B ₇ . Magnetic field sensitive component comprising the tape (1) according to one of the preceding claims, wherein the magnetically sensitive component is preferably a toroidal core, block or cut tape core. Magnetic field sensitive component according to Claim 7 , wherein the magnetically sensitive component is a toroidal core. Device for the galvanically separated measurement of a differential current, comprising a magnetic field sensitive component according to Claim 7 or 8th . Method for the galvanically separated measurement of a differential current with a magnetic field sensitive component according to Claim 7 or 8th comprising: measuring the magnetic field of active conductors which are guided as a primary winding through the magnetic field sensitive component; Determining whether the current flow in a secondary winding which is coupled via the magnetically sensitive component corresponds to a predetermined criterion; Output of a message about the presence of a differential current. Method for producing a tape (1) according to one of the Claims 1 - 6th comprising: a. Providing a band (1) made of a soft magnetic Fe-based alloy with the composition of the general formula: [Fe _1-a M _a ] _100-xyz - _α Cu _x Si _y B _z M ' _α, in which M Co and / or Ni is, M 'is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo and a, x, y, z and α each satisfy 0 ≤ a ≤ 0.5, 0.1 ≤ x ≤ 3, 0 ≤ y ≤ 30, 0 ≤ z ≤ 25, 5 ≤ y + z ≤ 30 and 0, 1 ≤ α <30, with at least 50% of the alloy structure being occupied by fine crystalline particles; b. Coating the strip (1) with MgO. Procedure according to Claim 11 wherein step b comprises: wetting the tape (1) in an aqueous solution comprising MgO; Drying the tape (1) until a coating (2) of MgO is formed on the tape. Procedure according to Claim 12 wherein step b comprises: wetting the tape (1) in an aqueous solution comprising MgO; Removing the aqueous solution comprising MgO on the underside (5) of the tape; and drying the tape (1) until a coating (2) of MgO is formed on the tape. Procedure according to Claim 13 wherein step b comprises: wetting the tape (1) in an aqueous solution comprising MgO; Removing the aqueous solution comprising MgO on the underside (5) of the belt (1); Application of an insulation layer (3) on the underside (5) of the tape (1); Drying the tape (1) until a water-free coating (2) of MgO is formed on the upper side of the tape and the insulation layer (3) on the underside (5) of the tape (1).

Images