TW202207255A - Magnetic core, manufacturing method of magnetic core electrode and inductor - Google Patents

Abstract

This invention provides a manufacturing method of magnetic core electrode comprises preparing a magnetic core contains magnetic powder and is insulated, performing a surface modification by laser in a predetermined area on the surface of the magnetic core so that the predetermined area is obtained metal particles and at least two space apart conductive area are formed and plating on each conductive area so as to form electrodes. By transforming the insulating surface into a conductive area via laser, the electrodes can be directly formed without using silver glue, thereby reducing the cost, and the adhesion between the electrodes and the magnetic core can be promoted. In addition, this invention also provides a manufacturing method of the magnetic cores and inductor.

Description

Magnetic core, manufacturing method of magnetic core electrode, and inductance element

The present invention relates to a magnetic core and a manufacturing method thereof, in particular to a manufacturing method of a magnetic core electrode, a magnetic core, and a passive element containing the magnetic core.

The magnetic core is usually composed of ferrite powder or alloy powder with low conductivity. Because of its high resistance and the unique coercive force of magnetic materials, it can be used in transformers, electromagnetic wave absorbing coatings or passive components. Among them, the inductive components are One of the common applications of magnetic cores. The basic structure of a traditional magnetic core inductor includes a die-cast magnetic core, a coil inside the magnetic core, and two electrode layers formed of metal materials plated on both sides of the magnetic core, and the two ends of the coil are The portions are respectively connected to the electrode layers. However, due to the insulating properties of the magnetic core surface, the electrode layers cannot be easily plated on the magnetic core surface by electroplating.

The existing method is that before the electrode layers are formed, the silver paste is coated on the magnetic core by means of printing or coating, etc., where the electrode layers are to be formed, and then the silver paste is sintered by heat treatment. A conductive silver paste layer is formed on the surface of the magnetic core, and then the silver paste layer is used as a medium for electroplating so that the subsequent electroplating process can be carried out, and the electrode layers can be formed on the silver paste layer . However, the use of silver glue will lead to a significant increase in production cost, and due to the insufficient bonding force between the silver glue layer and the magnetic core, if the magnetic core inductor is used for a long time, the electrode layers are easily removed from the magnetic core. stripped.

Therefore, the purpose of the present invention is to provide a method for manufacturing a magnetic core electrode, which can omit the use of silver glue and directly form electrodes on the magnetic core.

Therefore, the manufacturing method of the magnetic core electrode of the present invention includes a preparation step, a conductive step, and an electrode formation step.

The preparation step is to prepare a magnetic core body with magnetic powder and insulating properties.

The conducting step is to perform surface treatment on at least two predetermined areas spaced apart from each other by laser on the surface of the magnetic core body, so that the magnetic powder in the predetermined areas is excited by the laser and converted into conductive metal particles, Each predetermined area is modified into a conductive area having conductivity.

The electrode forming step is to form an electrode made of conductive material in each conductive area by means of coating.

Another object of the present invention is to provide a magnetic core with electrodes.

Therefore, the magnetic core with electrodes of the present invention includes a magnetic core body, at least two conductive regions, and at least two electrodes.

The core body has magnetic powder and is insulating.

The conductive regions have conductive properties and are spaced apart from each other on the surface of the magnetic core body. The conductive regions are formed by transformation of magnetic powder through laser excitation, and have the same metal particles as the metal of the magnetic powder.

The electrodes are respectively formed in the conductive regions and include at least one metal layer.

Furthermore, another object of the present invention is to provide an inductance element.

Therefore, the inductance element of the present invention includes a magnetic core with electrodes as described above, and a conductive coil in contact with the magnetic core body, and the two ends of the conductive coil are respectively connected with the electrodes of the magnetic core electrodes. connect.

The effect of the present invention is: through laser excitation, the magnetic powder in the predetermined area of the magnetic core body is reduced to metal particles, so that the conductivity of the surface of the magnetic core body is improved, and a conductive area with conductivity is formed, so that the The electrodes are formed by direct electroplating on the conductive area, thereby eliminating the use of silver glue to reduce production costs, and the electrodes have good adhesion between the magnetic core body and will not fall off easily.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are designated by the same reference numerals.

Referring to FIG. 6 , an embodiment of a method for manufacturing a magnetic core electrode of the present invention is used to manufacture a magnetic core having electrodes as shown in FIG. 6 .

The magnetic core with electrodes includes a magnetic core body 2 , at least two conductive regions 3 , and at least two electrodes 4 .

The magnetic core body 2 includes magnetic powders 20 with high resistance and has insulating properties. In the present embodiment, the magnetic powders 20 are made of iron-based alloys, such as iron-silicon, iron-silicon-chromium, and iron-silicon-aluminum. At least one of them is taken as an example, but not limited thereto.

The conductive regions 3 are located on the surface region of the magnetic core body 2 and are spaced apart from each other, and are formed from the magnetic powder 20 through laser processing, and have the same metal particles 31 as the magnetic powder 20 and have conductivity.

The electrodes 4 are made of conductive materials, in this embodiment, at least one selected from, for example, copper, nickel, tin, silver, and related alloy metals is used as an example, but not limited thereto. The electrodes 4 are respectively corresponding to and disposed in the conductive regions 3 for external electrical connection. Wherein, each electrode 4 can have a single-layer or multi-layer structure according to requirements. In FIG. 6, it is taken as an example that each electrode 4 has two metal layers 41 and 42. For example, the metal layer 41 can be nickel metal, and the metal The layer 42 may be tin metal, but the actual implementation is not limited to this.

Referring to FIG. 1 , an embodiment of the manufacturing method of the magnetic core electrode of the present invention includes a preparation step 51 , a conductive step 52 , and an electrode formation step 53 in sequence.

Referring to FIG. 1 and FIG. 2 , the preparation step 51 is to prepare the magnetic core body 2 first. In this embodiment, the magnetic core body 2 is obtained by placing the magnetic powder 20 in a mold and then die-casting the magnetic core body 2 as an example. However, the magnetic core body 2 has The actual production is not limited to this.

It should be noted here that the shape of the magnetic core body 2 can be in various shapes and states depending on requirements and applications, and no special limitation is required. For example, the magnetic core body 2 can be a cylindrical body as shown in FIG. 2 , or the magnetic core body 2 can also have a cylindrical body 21 as shown in FIG. 3 , and two from the cylindrical body 21 . The plates 22 are formed by extending from the ends. The plates 22 can be used to form the conductive regions 3 and the electrodes 4 , and can provide a larger area for external electrical connection than the columnar body 21 .

Next, referring to FIG. 1 , FIG. 4 and FIG. 5 , the conductive step 52 is performed, at least two predetermined areas 30 are defined on the surface of the magnetic core body 2 , the predetermined areas 30 are spaced apart from each other, and the Surface modification is performed on the magnetic core body 2 in the predetermined regions 30 , so that the magnetic powder 20 of the magnetic core body 2 in the predetermined regions 30 is excited and reduced by the laser to obtain metal particles 31 , and each predetermined region 30 is It is transformed into a conductive region 3 with conductivity. In addition, the conductive regions 3 and the electrodes 4 are not limited to be formed on opposite sides of the magnetic core body 2, but can also be formed on the same side. Taking the magnetic core body 2 of FIG. 3 as an example, these The conductive regions 3 and the electrodes 4 are located on different sides of the magnetic core body 2 respectively. However, in practice, the conductive regions 3 and the corresponding electrodes 4 may be formed only on the same surface of one of the plates 22 . , without special restrictions. Among them, the frequency selected by the aforementioned laser is between 20~400kHz, and the output power is between 1~100W. During the surface modification, the speed set by the laser is between 100~2000mm/s, and the distance between the spots is between 0.0001 ~1.0000 units, and one to several times of laser processing can be performed in the predetermined areas 30 according to requirements, so that the magnetic powder 20 in the predetermined areas 30 can receive enough energy to be converted into metal particles 31 . In some embodiments, the laser may be a fiber laser, a carbon dioxide laser, or a violet laser.

The magnetic powder 20 is selected from alloy metal powder (for example: iron-silicon-chromium alloy). Therefore, when the surface of the magnetic core body 2 is modified by a laser, the metal of the magnetic powder 20 located on the surface of the magnetic core body 2 The ions can obtain the energy from the laser and be reduced to a metallic state, that is to say, in the predetermined regions 30, the magnetic powder 20 on the surface of the magnetic core body 2 is made of the original high-resistance metal oxide or alloy powder, The energy provided by the laser undergoes a redox reaction, and is reduced to produce low-resistance and corresponding metal particles 31 , and the originally insulated predetermined region 30 is modified into a conductive region 3 with electrical conductivity.

In addition, in some embodiments, the outer surface of the magnetic core body 2 can also be coated with an insulating polymer layer (not shown) composed of insulating materials such as epoxy resin, para-xylene, etc., or the The magnetic powder 20 has a core-shell structure surrounded by an insulating polymer layer (not shown), and the surface of the magnetic core body 2 composed of the magnetic powder 20 is covered with an insulating polymer layer. At this time, the conducting step 52 may be performed in stages, firstly removing the insulating polymer layer, and then modifying the surface of the magnetic core body 2 exposed from the predetermined area 30 , or through laser The power is set so that after the laser intensity is enough to remove the insulating polymer layer located in the predetermined area 30, there is still enough energy to directly modify the exposed surface of the magnetic core body 2, so that a single The step simultaneously removes the insulating polymer layer and transforms the surface of the magnetic core body 2 into a conductive region 3 with electrical conductivity.

1 and FIG. 6 , then, the electrode forming step 53 is performed, and the surface of each conductive region 3 is plated by electroplating or electroless plating to form the electrode 4 , and the magnetic core electrode is obtained. Since the control of the materials used in the aforementioned electroplating and electroless plating and the related process parameters are well known to those skilled in the art, further descriptions are omitted here.

The aforementioned magnetic core with electrodes can be applied to passive components such as transformers, capacitors, and inductors. Not limited to this.

Referring to FIG. 7 and FIG. 8 , the magnetic core with electrodes in this embodiment can be applied to an inductor to form an inductor element 6 .

The inductance element 6 includes a magnetic core 61 with electrodes as described above, and a conductive coil 62 . The conductive coil 62 can be embedded in the magnetic core body 2 as shown in FIG. 7 , and the two ends of the conductive coil 62 can be exposed to the conductive regions 3 to connect with the electrodes 4 ; or as shown in FIG. 8 . It is shown wound around the periphery of the magnetic core body 2 , and then the two ends of the conductive coil 62 are respectively connected to the electrodes 4 .

When the inductance element 6 as shown in FIG. 7 is to be produced, the conductive coil 62 can be embedded in the magnetic powders 20 in the aforementioned preparation step 51 , and then die-cast by die casting to form the conductive coil 62 . The coil 62 is embedded in the magnetic core body 2, and the two ends of the conductive coil 62 are controlled to be located in the conductive regions 3 correspondingly and exposed to the conductive regions 3. Therefore, after the electrode forming step 53, the The inductance element 6 can be obtained by connecting both ends of the conductive coil 62 to the electrodes 4 .

The following specific examples 1 to 3 are used to illustrate the magnetic core electrodes obtained by performing the conductive step 52 on the magnetic core body 2 by selecting different laser parameters.

Specific example 1

A magnetic core body 2 made of iron-silicon-chromium magnetic powder obtained through the preparation step 51 is prepared, and the conductive step 52 is performed in the predetermined area 30 on the surface of the magnetic core body 2 . In this specific example, a fiber laser with a frequency of 200 kHz and a power of 50% is selected for surface treatment, and a speed of 1000 mm/s and a light spot distance of 0.035 units are used to conduct several single lasers within the predetermined areas 30. Directional operation, the number of lasers is 1 time to form the conductive regions 3 . Then, in the electrode forming step 53, a nickel metal layer is formed on the surface of each conductive region 3 by electroplating, and then the nickel metal layer is used as the electroplating surface to form a tin metal layer by electroplating.

Specific example 2

The specific example 2 is similar to the specific example 1 in terms of materials and manufacturing processes. The difference is that the specific example 2 uses a fiber laser for surface treatment. The speed is 2000 mm/s, the spot distance is 0.05 unit, and the conductive regions 3 are formed by performing multiple operations in a single direction in the predetermined regions 30, and the number of lasers is 1 time.

Specific example 3

The specific example 3 is similar to the specific example 1 in terms of materials and manufacturing processes. The difference is that the specific example 3 is used for surface treatment in the predetermined areas 30 through optical fiber lasers. The set laser parameters are frequency 200 kHz and power are 30%, and at a speed of 1000 mm/s and a light spot distance of 0.0075 units, several unidirectional operations are performed in the predetermined areas 30, and the number of lasers is 2 times to form the conductive areas 3.

Comparative example

The magnetic core body 2 of the comparative example is the same as that of the specific example 1, the difference is that the magnetic core electrode of the comparative example is prepared by applying silver glue before the predetermined areas 30 of the magnetic core body 2, and passing the temperature at 150° C. After sintering at ~250°C or 700°C to 800°C, a conductive medium layer is formed, and then a metal layer is formed on the conductive medium layers by the same process as in the specific example 1, respectively.

Next, the electrode adhesion test and vertical peel strength test were performed on the magnetic cores with electrodes prepared in the above-mentioned specific examples 1 to 3 and this comparative example to further confirm the adhesion of the electrodes 4 . The test results of the specific examples 1 to 3 and the comparative example are listed in Table 1.

Adhesion Test:

The magnetic cores with electrodes prepared by the specific examples 1 to 3 and the comparative example were respectively immersed in a tin furnace with a temperature of 395° C. for 3 seconds, and the adhesion of the electrodes 4 to the magnetic core body 2 was observed.

Vertical peel strength test:

The magnetic cores with electrodes prepared in the specific examples 1 to 3 and the comparative example are respectively welded to the conductive lines of a test circuit board through the electrodes 4 by surface soldering technology (SMT), and along the conductive lines of the test circuit board. The magnetic cores are slowly applied in a direction perpendicular to and away from the circuit board to detect the vertical peel strength of the electrodes 4 peeled off from the circuit board.

Table 1 Adhesion test (whether the electrode is peeled off) Vertical peel strength (N) Specific example 1 not stripped 16.5 Specific example 2 not stripped 16.2 Specific example 3 not stripped 16.0 Comparative example peel off 13.2

Referring to Table 1, in this adhesion test, the magnetic cores with electrodes prepared by specific examples 1 to 3 and comparative Waiting for the adhesion of the electrodes 4, it can be known that the electrodes 4 prepared by the aforementioned specific examples 1 to 3 can still be attached to the magnetic core body 2 without falling off after being soaked in a high-temperature tin furnace. Compared with the electrodes of the comparative example after being soaked in a tin furnace under the same conditions, the electrodes detached from the magnetic core body 2 , the electrodes 4 obtained by the manufacturing method of this embodiment have better adhesion.

In the vertical peel strength test, the electrodes 4 prepared by the processes of Examples 1 to 3 had a vertical peel strength of about 16 to 17 N (as shown in Table 1). That is to say, the electrode formed by electroplating with silver glue as a medium in the traditional way has a vertical peel strength of about 13.2N. The electrodes 4 are formed by plating directly on the conductive regions 3 , and the adhesion of the electrodes 4 will not decrease because the use of silver paste is omitted.

In addition, the coverage area of the electrodes 4 on the conductive regions 3 formed by the manufacturing methods of the aforementioned specific examples 1 to 3 is greater than 95%, that is to say, in the conductive step 52, a laser treatment method is used The predetermined regions 30 that are originally insulating properties can be effectively modified into the conductive regions 3 with electrical conductivity, and the surfaces of the conductive regions 3 formed by laser irradiation are dense structures. Therefore, The electrodes 4 subsequently formed in the conductive regions 3 will also have a continuous and dense structure, so that the structure of the electrodes 4 formed by the present invention can be better than the electrode structures fabricated by the conventional method.

To sum up, in the present invention, the surface treatment is performed by a laser method, so that the magnetic powder 20 on the surface of the magnetic core body 2 obtains energy and is reduced to metal particles 31 , so that the magnetic core body 2 with the original surface is insulated to form several The conductive regions 3 are electrically conductive, so the electrodes 4 can be directly formed on the conductive regions 3 by means of coating (electroplating or electroless plating), and the conventional method of forming electrodes on the surface of the insulating magnetic core can be omitted. The disadvantage of using silver glue as the conductive medium layer is that the production cost is greatly reduced, and the electrodes 4 are continuous and dense in structure and have good adhesion with the magnetic core body 2, and will not be easily peeled off, so the magnetic field can be improved. The product yield and service life of the core electrode can indeed achieve the purpose of the present invention.

However, the above are only examples of the present invention, and should not limit the scope of implementation of the present invention. Any simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the contents of the patent specification are still included in the scope of the present invention. within the scope of the invention patent.

2: Magnetic core body 20: Magnetic powder 21: Cylinder 22: Board body 30: Reservation area 3: Conductive area 31: Metal Particles 4: Electrodes 41, 42: Metal layer 51: Preparation steps 52: Conductivity step 53: Electrode forming step 6: Inductive components 61: Magnetic core 62: Conductive coil

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, wherein: FIG. 1 is a flow chart illustrating an embodiment of a method for manufacturing a magnetic core electrode of the present invention; FIG. 2 is a schematic diagram illustrating a preparation step of the embodiment, and an aspect of a magnetic core body; 3 is a schematic diagram illustrating another aspect of the magnetic core body in this embodiment; FIG. 4 is a schematic diagram illustrating a conductive preparation step of this embodiment in continuation of FIG. 2; Fig. 5 is a partial schematic diagram to assist in illustrating the enlarged view of A in Fig. 4, illustrating the structure of this embodiment; FIG. 6 is a schematic diagram illustrating an electrode forming step of this embodiment following FIG. 4 . FIG. 7 is a schematic diagram illustrating an embodiment of the inductive element of the present invention; and FIG. 8 is a schematic diagram illustrating another aspect of the inductive element.

51: Preparation steps

52: Conductivity step

53: Electrode forming step

Claims (10)

A method for manufacturing a magnetic core electrode, comprising: A preparation step, preparing a magnetic core including magnetic powder and having insulating properties; In a conductive step, laser processing is performed on at least two predetermined areas on the surface of the magnetic core body, so that the magnetic powder in the predetermined areas is excited by the laser and converted into conductive metal particles, and each predetermined area is converted into conductive metal particles. into a conductive region with electrical conductivity; and In an electrode forming step, an electrode composed of a conductive material is formed in each conductive area by means of a coating method. The method for manufacturing a magnetic core electrode according to claim 1, wherein the types of lasers selected in the conductive step are fiber lasers, carbon dioxide lasers, and violet lasers. The method for manufacturing a magnetic core electrode according to claim 1, wherein, in the conductive step, the frequency selected for the laser is between 20 and 400 kHz, and the power is between 1 and 100 W. The manufacturing method of the magnetic core electrode according to claim 1, wherein, in the conductive step, the speed set by the laser is between 100 and 2000 mm/s. The method for manufacturing a magnetic core electrode as claimed in claim 1, wherein, in the conductive step, the distance between the spots of the laser is between 0.0001 and 1.0000 units. The method for manufacturing a magnetic core electrode according to claim 1, wherein the electrode forming step is to form the electrode from the surface of each of the conductive regions by means of electroplating. A magnetic core with electrodes comprising: a magnetic core body with magnetic powder and insulating properties; At least two conductive regions are located on the surface of the magnetic core body and are spaced apart from each other and have electrical conductivity, the conductive regions are transformed from magnetic powder by laser processing and have metal particles that are the same as the metal of the magnetic powder; and At least two electrodes are respectively disposed in each of the conductive regions and include at least one metal layer. An inductive element comprising: A magnetic core having electrodes as claimed in claim 7; and A conductive coil is in contact with the magnetic core, and two ends of the conductive coil are respectively connected with the electrodes of the magnetic core. The inductance element as claimed in claim 8, wherein the conductive coil is embedded inside the magnetic core body, and both ends of the conductive coil are exposed on the surface of the magnetic core body and are respectively connected to the electrodes. The inductance element according to claim 8, wherein the conductive coil is wound around the periphery of the magnetic core body.

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