KR101215236B1 - Method for providing a isolation coating and assembly thereby - Google Patents

Abstract

The present invention relates to a method for providing an insulating coating and thus a soft magnetic assembly, and more particularly to a process of forming an insulating material between adjacent metal layers of a soft magnetic core, and more particularly, storage and coating of a coating liquid comprising an insulating material. by to occur in a nitrogen (N ₂₎ atmosphere, it is possible to solve the agglomeration problem during pre-gel, and coating the coating solution.

Description

Method for providing a isolation coating and assembly thereby

FIELD OF THE INVENTION The present invention relates to a method of providing insulation between adjacent metal layers of a magnetic core (magnetic core) and to a soft magnetic core produced by the method, in particular a method of storing and coating an insulating material that restricts electrical flow between layers. It is related to, and more particularly, to solve the problem of pre-gelling and coating of the conventional coating solution.

The magnetic material has at least two forms of hard or soft. The light magnetic material is a permanent magnet, which retains its magnetic properties after the electric field is removed. Examples of light magnetic materials include common refrigerator magnets. In contrast, soft magnetic materials have a magnetic field that collapses when the electric field is removed. Examples of soft magnetic materials include electromagnets. Soft magnetic materials are widely used in electrical circuits as components of transformers, inductors, inverters, switch power supplies, and the like. Soft magnetic materials are also used to create magnetic cores that provide large energy storage, rapid energy storage and efficient energy recovery.

Most magnetic cores are made by winding very thin magnetic metal strips or ribbons tightly around the base rod to form a multilayer laminate. The wound metal core undergoes a heating step called "annealing", in which it optimizes its performance through heat-induced ordering of the magnetic domains in the metal. After the annealing step, the basal rod can be removed and treated with a binder to fix it with the adjacent metal layer so that the magnetic core does not loosen.

According to the prior art, such a binder includes an epoxy, which contains a binder such as Hysol # 4242 resin and # 3401 curing agent (Olean, NY) or # 2076 impregnation epoxy of Three Bond Co. Have 2 items. By conventional techniques, treatment with a binder allows the magnetic core to be cut to form a C or E magnetic core, which is named because the resulting cutting magnetic core resembles a C or E shape.

The metal strip or ribbon layer which produces the magnetic core is very thin and generally has a thickness of 0.01 to 0.3 mm. For high frequency applications of 400 kHz or more, each metal layer of the winding magnetic core can be electrically insulated from each other so that the core functions to function properly. Without this insulation, at high frequencies the magnetic core has electrical properties similar to that of large metal blocks and will suffer significant power losses due to eddy currents.

In order to provide insulation between layers, prior art generally coats a metal ribbon with an insulating material prior to winding the ribbon for magnetic core formation. This insulating material is generally coated on both sides of the ribbon and functions to insulate the metal layer of the winding laminate from adjacent metal layers. One widely used coating method by Suchoff is presented in US Pat. No. 2,796,364, which discloses a method of forming a layer of magnesium oxide on a metal ribbon surface as an insulating layer. According to Suchoff, methyl magnesium is dissolved in an organic solvent and the solution is applied to the metal ribbon surface. The metal ribbon is then heated to high temperature to form magnesium oxide with strong adhesion to the surface of the metal ribbon. The metal ribbon can then be wound to form a magnetic core.

However, several disadvantages are known for the methyl magnesium process. First, methyl magnesium must be provided to the metal ribbon before the ribbon can be wound. Uncoiling metal ribbons, dipping in a bath for coating, heating and curing the coating, and winding to create a magnetic core delays the process and increases costs . The methyl magnesium process is therefore not suitable for applications that provide insulation at low cost and in large quantities. Second, it is very difficult to control the thickness of the obtained magnesium oxide insulating layer. This is a problem in some applications where magnetic cores are used, for example pulse cores where high performance specifications are difficult to meet unless the coated methyl magnesium layer is very thin. Special processes are required to form thin methyl magnesium coatings, which are very slow and difficult to control. The use of methyl magnesium for these applications is very expensive and the magnetic core obtained is also fragile. Also, in applications where a thick insulating layer is acceptable, the excessive non-conductive insulating layer takes up valuable space for the core. This reduces the spatial component of the laminated stack, thus reducing the percentage of magnetic material in the magnetic core, reducing the efficiency of the magnetic core. Finally, because methyl magnesium must be coated before the annealing step, stress may accumulate between the coating and the soft magnetic material and interfere with the arrangement of the magnetic regions during annealing.

The methyl magnesium process also cannot be used to form an insulating layer for any kind of magnetic core. High temperatures are required to properly cure methyl magnesium on the metal ribbon. In general, the methyl magnesium coating should be heated to a temperature of at least 843 ° C. (1550 ° F.) or higher to form a magnesium oxide film that adheres firmly to the metal ribbon. However, some soft magnetic materials, such as amorphous metal alloys, cannot be heated to temperatures above about 449 ° C. (840 ° F.) because their desirable magnetism is destroyed. If methyl magnesium is used as the insulating material for this kind of metal alloy, it is heated to much lower temperatures, and the resulting magnesium oxide layer is inevitably bound loosely to the metal ribbon. As a result, this kind of magnetic core cannot be cut to form C or E magnetic cores, since stressful cutting operations break up loosely bonded insulating coatings. Only cyclic, non-cut magnetic cores can be formed from the amorphous metal alloy coated by the methyl magnesium process.

In addition, in the case of forming an oxide film using a magnesium suspension on a permalloy metal layer mainly composed of nickel and iron, the suspension, which is a colloidal phase, may be solidified before coating by pre-gelling at the time of storage, and also at the time of coating of the suspension. There is a disadvantage in that the surface is agglomerated on the surface before completion of the coating by combining with oxygen, and thus there is a problem that the metal layer and the coating layer are fused and adhered to each other even when the coil is wound on the recoiler after coating.

Accordingly, there is a need to improve the method of forming thin insulating coatings on soft magnetic metal ribbons used to make magnetic cores. There is also a need for insulation that allows the treatment of amorphous metal magnetic cores to form C and E magnetic cores that can be used at high frequencies.

The present invention for solving the above problems is an object to solve the problem of pre-gelling and coating the coating liquid containing the insulating material in forming an insulating material between the adjacent metal layer of the soft magnetic core.

One aspect of the present invention for achieving the above object is a method of providing isolation between adjacent layers of a stacked magnetic assembly having a plurality of layers, the stacked magnetic assembly Providing an uncoiled layer of an uncoil by uncoiler, and applying a coating liquid containing magnesium (Mg) ions to the one layer in a nitrogen (N ₂ ) atmosphere, and the coating liquid Drying and curing the applied one layer, and coiling the cured one layer by a coiler.

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Specific details of other embodiments are included in the detailed description and the drawings.

The present invention is characterized in that the storage and coating of the coating solution containing the insulating material is made in a nitrogen (N ₂ ) atmosphere, by minimizing the inflow of oxygen by the nitrogen molecules, magnesium oxide (MgO) on the surface Can minimize the aggregation.

1 is a process chart for explaining the process of the method for providing an insulating coating according to an embodiment of the present invention,
2 is a SEM (Scanning Eletron Microscope) photograph of the surface coated with an insulating layer by a method for providing an insulating coating according to an embodiment of the present invention,
3 is an SEM photograph of a control surface that is not insulated coated according to the prior art,
Figure 4 is a graph showing the results of the EDS DATA surface composition analysis of the surface coated with the insulating layer by a method for providing an insulating coating according to an embodiment of the present invention,
5 is a graph showing the results of EDS DATA surface composition analysis of the control surface without the insulating coating according to the prior art,
6 and 7 are photographs for explaining the condensation (condensation) occurs on the surface coated with the insulating layer without using nitrogen gas, respectively, according to the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and will be described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The present invention is directed to a method of providing isolation between adjacent layers of a stacked magnetic assembly having a plurality of layers. That is, the present invention relates to a natural metal oxide insulating component that can be formed in a magnetic core after the magnetic core is wound. In winding annular magnetic cores, it will be readily understood by the prior art that the principles of the present invention can be applied to magnetic cores having various shapes and dimensions. In one embodiment of the invention, the laminated magnetic assembly may be a winding core. For example, the present invention can be readily applied as part of a process for forming C magnetic cores, E magnetic cores, and other laminate magnetic assemblies by the prior art. The invention can also be applied to a magnetic assembly comprising an unwound laminate, for example laminates that build up a continuous layer by forming a continuous layer.

The present invention features a process of forming an insulating material between adjacent metal layers of a soft magnetic core, wherein the storage and / or coating of the coating liquid comprising the insulating material is carried out in a nitrogen (N ₂ ) atmosphere, thereby pre-gelling and / or Or it is possible to solve the problem of aggregation during coating.

This process according to the invention can be used to provide insulation to steel sheets including various metals used to make the magnetic core, and amorphous metal alloys. The insulating material formed by the process of the present invention is firmly bonded to the surface of the metal ribbon forming the magnetic core, the magnetic core comprising the insulating material being cut to form a C or E magnetic core, or other magnetic cores known in the prior art. It is possible.

In one embodiment of the present invention, when the laminated magnetic assembly is described as a winding core, for example, the present invention first provides a layer of the laminated magnetic assembly. That is, uncoil one layer of the laminated magnetic assembly by an uncoiler. It may also be to uncoiling the metal ribbon wound around the magnetic core of the winding core and dipping it into a bath for coating.

Next, the present invention is to apply a coating solution containing a divalent cation in one layer of the laminated magnetic assembly in a nitrogen (N ₂ ) atmosphere. That is, the present invention is to use an inert gas in order to suppress the hydrolysis effect of the coating liquid, it is characterized by using a nitrogen gas (N ₂ ) that is particularly heavy and easy to supply. Through this, by minimizing the inflow of oxygen by the nitrogen molecules, it is intended to minimize the aggregation of magnesium oxide (MgO) on the surface.

The divalent cation-containing coating solution includes all the various coating solutions known in the art, and in one embodiment, may be a suspension (Colloid solution) in which a certain amount of magnesium methoxide is synthesized on magnesium ethoxide. The divalent cation is preferably magnesium (Mg) ion.

The coating technology according to the present invention is based on the sol-gel method, which is a physical vapor deposition method. The sol-gel method is obtained by dissolving dozens and hundreds of nm colloid particles obtained by hydrolysis or dehydration condensation and fine particles obtained by flame hydrolysis of sol dispersed in a liquid. This is a reaction in which the fluidity of the sol state (Sol) is lost due to the aggregation and condensation of colloidal particles in the state, and thus becomes a gel of the porous body.

The coating solution is hydrolyzed (Hydroysis) reaction in the atmosphere, the deposition proceeds to the material surface, in order to prevent the aggregation problem during coating of the insulating material, by injecting nitrogen gas into the coating solution coating section of the solution in the coating machine By inducing convection, autonomous precipitation of the solution can be prevented and the hydrolysis effect can be suppressed.

In one embodiment, the present invention preferably further comprises the step of preparing the coating solution by storing it in a nitrogen (N ₂ ) atmosphere. For example, before or after providing a layer of the laminated magnetic assembly, preferably before the coating liquid is applied in a nitrogen (N ₂ ) atmosphere, nitrogen may also be supplied to a storage container for storing the coating liquid. have.

In order to prevent solidification due to pre-gelling of the coating liquid before surface deposition, dry nitrogen gas is flowed into the coating liquid storage container to minimize the content of moisture to prevent solidification due to hydrolysis in the container before coating. According to the present invention, when the coating solution is stored in a nitrogen (N ₂ ) atmosphere, the moisture content is minimized by nitrogen gas in the storage container and the atmospheric exposure is suppressed to the maximum, thereby preventing solidification due to hydrolysis in the container before coating. have.

As described above, after applying the coating liquid, it is preferable to coil one layer to which the coating liquid is applied by a coiler. For example, one layer to which the coating solution is applied may be dried and cured, and the cured one layer may be coiled by a coiler. In other words, the coating is heated and cured, and then wound to create a magnetic core.

In one embodiment, it is desirable to completely surface deposit the material via high temperature drying at 150 ° C. using an air knife to ensure complete gelation prior to the recoiling process and then recoil.

The present invention may be better understood by the following examples, which are for the purpose of illustrating the invention and are not intended to limit the scope of protection defined by the appended claims.

Example  : Insulation coating using nitrogen gas

1 is a flowchart illustrating a process of a method of providing an insulating coating according to an embodiment of the present invention.

As shown here, first, the raw material wound in the form of a coil was mounted on the uncoiler 10 and then transferred to the coating liquid applicator 30 containing the coating liquid through the calibrator 20. Here, as the coating solution, a suspension (Colloid solution) in which magnesium ethoxide and magnesium methoxide were mixed was used.

Then, a coating insulating film was formed while supplying nitrogen gas into the coating solution applicator 30. The coating liquid applicator 30 is coupled to the nitrogen gas storage container 31 that can supply nitrogen gas therein, the nitrogen gas storage container 31 is to supply nitrogen to the coating liquid storage container (32). It is possible. Thereafter, the air knife was used as the dryer 40 to deposit the gelation completely on the surface of the material through high temperature drying at 150 ° C., and wound the recoiler 50.

Comparative example  : Insulation coating without using nitrogen gas

Except that the nitrogen gas was not supplied to the coating liquid applicator 30 in the above embodiment, the insulation coating was performed in the same manner as in the above embodiment.

Experimental Example  : Surface analysis and characteristic test

The surface analysis and the characteristic test were carried out on the core layers wound and coated by the examples and the comparative examples, respectively. In addition, the same experiment was carried out on the raw material without an insulating coating as a control.

FIG. 2 is a scanning electron microscope (SEM) photograph of a surface coated with an insulating layer by a method of providing an insulating coating according to an embodiment of the present invention, and FIG. 3 is a SEM of a control surface without an insulating coating according to the related art. It is a photograph. As can be seen, when the insulation coating according to the present invention, it can be confirmed that the insulating layer is formed on the surface.

And, Figure 4 is a graph showing the results of EDS DATA surface composition analysis of the surface coated with the insulating layer by a method for providing an insulating coating according to an embodiment of the present invention, Figure 5 is not insulating coating in accordance with the prior art It is a graph showing the results of surface component analysis of EDS DATA on the control surface. In Figure 4, as shown in the Mg component, when the insulation coating according to the present invention, it can be confirmed once again that the MgO insulating layer formed on the surface.

In addition, Table 1 and Table 2 show the surface component ratio of the core layer according to the embodiment of the present invention and the comparative example, respectively.

  Element Series unn. [Wt.%] C norm. [Wt.%] C Atom. [At.%] C Error [%] Iron k-series 44.34 43.70 34.18 2.4 Nickel K-series 39.18 38.62 28.74 2.1 Magnesium K-series 11.09 10.93 19.65 1.3 Oxygen K-series 5.01 4.94 13.47 1.4 Carbon k-series 0.66 0.65 2.38 0.3 Aluminum K-series 0.44 0.44 0.71 0.1 Silicon k-series 0.39 0.39 0.60 0.1 Manganese k-series 0.34 0.34 0.27 0.1 sub Total 101.46 100.00 100.00

 El an Series unn. [Wt.%] C norm. [Wt.%] C Atom. [At.%] C Error [%]  O 8 K-series 33.49 28.00 47.12 3.9  Mg 12 K-series 31.84 26.62 29.50 1.8  Fe 26 K-series 28.05 23.45 11.31 0.8  Ni 28 K-series 23.48 19.63 9.01 0.6  Si 14 K-series 1.24 1.04 0.99 0.1  C 6 K-series 0.89 0.74 1.67 0.2  Al 13 K-series 0.35 0.29 0.29 0.0  Mn 25 K-series 0.28 0.23 0.11 0.0        sub Total 119.62 100.00 100.00

As shown in Table 1 and Table 2, permalloy material (Nickel, Iron, etc.) was not detected in the embodiment (Table 1) of the present invention. In addition, the high component ratio of the surface coating in the embodiment (Table 1) of the present invention can be interpreted that the MgO (magnesium oxide) coating is uniformly applied to the surface, no cracking occurs.

In addition, Table 3 below shows the magnetic properties, electrical properties, and loss values of the core layer according to the embodiment of the present invention and the comparative example.

division Comparative example Example Magnetic properties


B (Gauss) 28000Gauss 30000Gauss Hm (A / m) 480 (A / m) 500 (A / m) Hc (A / m) 45 (A / m) 50 (A / m) 13758 14069 Electrical characteristics

inductance 270H 300H resistance 18KΩ 10KΩ Output voltage 1200voltage 1200voltage Loss value

Core Loss 4-5% 2 to 3% Voryuson 1 to 3% 0.1 ~ 2% Iron loss Less than 3% Less than 2%

As shown in Table 3, according to the embodiment of the present invention it can be seen that the magnetic properties and electrical properties are superior to that of the comparative example, and the loss value is also significantly smaller.

In the case of the comparative example, MgO particles were generated by oxygen molecules (O ₂ ) in the atmosphere, which accelerated the aggregation of particles, thereby causing the crystals, and the crystals were grown and condensed. In contrast, according to an embodiment of the present invention, it is determined that nitrogen molecules (N ₂ ) form a layer to reduce the inflow of oxygen into the atmosphere, thereby minimizing the aggregation of particles on the surface.

6 and 7 are photographs for explaining the condensation (condensation) occurs on the surface coated with the insulating layer without using nitrogen gas, respectively, according to the prior art. Here, the white powder is magnesium oxide powder in which magnesium of the coating liquid is oxidized.

This aggregation occurred not only in the coating liquid applicator 30 in which the coating is made, but also in the coating liquid storage container 32 in which the coating liquid is stored.

10: uncoiler 20: braces
30: coating liquid applicator 31: nitrogen gas storage container
32: coating liquid storage container 40: dryer
50: recoiler

Claims (7)

delete delete delete delete delete A method of providing isolation between adjacent layers of a stacked magnetic assembly having a plurality of layers, the method comprising:
Uncoiling and providing one layer of the stacked magnetic assembly by an uncoiler;
Applying a coating solution containing magnesium (Mg) ions to the one layer in a nitrogen (N ₂ ) atmosphere;
Drying and curing the one layer to which the coating solution is applied;
Coiling the cured one layer by a coiler.
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