Preparation method of copper-magnetic co-fired inductor and copper-magnetic co-fired inductor

Abstract

The invention provides a preparation method of a copper-magnetic co-fired inductor, which comprises the following steps: providing a copper material required for preparing the inductor, stamping and bending the copper material to obtain a plurality of rows of inductor material sheets, and each inductor material sheet comprises material sheet units which are sequentially connected and are shaped like a Chinese character'ji '; the inductance material piece is placed in a forming die, magnetic powder is filled in the forming die to be pressed and formed, and the magnetic powder is one or more of iron silicon, iron silicon chromium, iron silicon aluminum, iron nickel, iron nickel molybdenum and carbonyl iron; and putting the pressed and molded inductor material sheet into a sintering furnace for sintering, thereby obtaining an inductor group consisting of a plurality of inductor units. The inductor solves the problem that an inductor in the prior art has large leakage magnetic flux.

Description

Technical Field

[0001] The present invention relates to the technical field of inductor manufacturing, and particularly relates to a preparation method of a copper-magnetic co-fired inductor and a copper-magnetic co-fired inductor. Background Art

[0002] Inductors, especially integrated inductors, are an indispensable part of electronic information and its peripheral devices. For traditional integrated inductors, after winding an enameled wire into a coil, powder is filled and molded by pressing, then cured at a low temperature, and the pins are bent and formed. Inductors with this structure have a problem of relatively large leakage magnetic flux. Summary of the Invention

[0003] In view of this, an object of the present invention is to provide a preparation method of a copper-magnetic co-fired inductor and a copper-magnetic co-fired inductor, aiming to solve the problem of relatively large leakage magnetic flux in inductors in the prior art.

[0004] An object of the present invention is to provide a preparation method of a copper-magnetic co-fired inductor, and the method includes:

[0005] Providing copper materials required for preparing the inductor, stamping and bending the copper materials to obtain multi-row inductor wafers, and each inductor wafer includes a "J"-shaped wafer unit connected in sequence;

[0006] Putting the inductor wafers into a molding die, filling with magnetic powder and pressing into shape, wherein the magnetic powder is one or more of iron silicon, iron silicon chromium, iron silicon aluminum, iron nickel, iron nickel molybdenum, and carbonyl iron;

[0007] Putting the inductor wafers pressed into shape into a sintering furnace for sintering to obtain an inductor group composed of multiple inductor units.

[0008] Further, in the above preparation method of the copper-magnetic co-fired inductor, the pressure for pressing into shape is 100 Mpa to 800 Mpa.

[0009] Further, in the above preparation method of the copper-magnetic co-fired inductor, the temperature for pressing into shape is 100 °C to 180 °C, and the time is 60 s to 180 s.

[0010] Further, in the above preparation method of the copper-magnetic co-fired inductor, the magnetic powder, clay, and high-temperature resistant silicone resin are filled and pressed into shape in a ratio of 94 wt%: 1 wt%: 5 wt%.

[0011] Further, in the above preparation method of the copper-magnetic co-fired inductor, the sintering temperature is 650 °C to 850 °C.

[0012] Further, in the above preparation method of the copper-magnetic co-fired inductor, the sintering time is 60 min to 360 min.

[0013] Further, in the method for preparing the copper-magnetic co-fired inductor, the sintering atmosphere is a mixed atmosphere of nitrogen and hydrogen, and the flow ratio of nitrogen to hydrogen is 3:1.

[0014] Further, in the method for preparing the copper-magnetic co-fired inductor, after the step of placing the well-compacted inductor wafer into a sintering furnace for sintering to obtain an inductor group composed of multiple inductor units, the method further includes:

[0015] Cutting the inductor group in the longitudinal direction to obtain multiple inductors, then impregnating the magnets of the cut inductors with resin, and finally painting the magnets.

[0016] Further, in the method for preparing the copper-magnetic co-fired inductor, after the step of cutting the inductor group in the longitudinal direction to obtain multiple inductors, then impregnating the magnets of the cut inductors with resin, and finally painting the magnets, the method further includes:

[0017] Determining the terminals at the side pins of the inductor, and removing the paint covering the terminals to expose the terminals;

[0018] Electroplating a conductive material composed of copper, nickel, and tin at the paint-removed position to connect with the exposed terminals and the magnetic core body.

[0019] Another object of the present invention is to provide a copper-magnetic co-fired inductor prepared by using the above method for preparing the copper-magnetic co-fired inductor.

[0020] Compared with the prior art: In the embodiment of the present invention, by providing the copper material required for preparing the inductor, stamping and bending the copper material to obtain multiple rows of inductor wafers, and each inductor wafer includes a "J"-shaped wafer unit connected in sequence; placing the stamped and bent copper material into a mold, filling it with magnetic powder and compacting it, wherein the magnetic powder is one or more of iron-silicon, iron-silicon-chromium, iron-silicon-aluminum, iron-nickel, iron-nickel-molybdenum, and carbonyl iron; placing the well-compacted copper material into a sintering furnace for sintering to obtain an inductor with high magnetic permeability. The leakage magnetic flux caused by the bending of the terminals can be reduced by the "J"-shaped copper material, reducing the exposure of the electrodes, thereby reducing the inductor leakage magnetic flux and improving the inductor performance. The problem of large leakage magnetic flux existing in the inductors in the prior art is solved.

[0021] In addition, the present invention at least further has the following beneficial effects:

[0022] 1) The preformed "J"-shaped copper material can break through the thickness limitation and give full play to the current-carrying capacity of the conductor;

[0023] 2) The whole-board stamping of the copper material can realize automated production and improve production efficiency. Description of the Drawings

[0024] Figure 1 It is a flow chart of a method for preparing a copper-magnetic co-fired inductor proposed in one embodiment of the present invention;

[0025] Figure 2 This is a diagram of the inductor full-plate molding structure in the method for preparing the copper-magnetic co-fired inductor proposed in one embodiment of the present invention;

[0026] Figure 3 FIG. 1 is a diagram of the structure of an inductor after cutting in a method for preparing a copper-magnetic co-fired inductor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0029] In addition, the term "and / or" as used herein includes any and all combinations of one or more related listed items. In the detailed description and claims, a list of items connected by the term "one of" may mean any of the listed items. For example, if items A and B are listed, the phrase "one of A and B" means only A or only B. In another example, if items A, B, and C are listed, the phrase "one of A, B, and C" means only A; only B; or only C. Item A may contain a single element or multiple elements. Item B may contain a single element or multiple elements. Item C may contain a single element or multiple elements. In the detailed description and claims, a list of items connected by the terms "at least one of", "at least one of" or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, the phrase "at least one of A and B" or "at least one of A or B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, the phrase "at least one of A, B, and C" or "at least one of A, B, or C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may include a single element or multiple elements. Item B may include a single element or multiple elements. Item C may include a single element or multiple elements.

[0030] The present invention aims to solve the problem of large magnetic flux leakage in current inductors and proposes a method for preparing a copper-magnetic co-fired inductor. Figure 1 , wherein the method comprises:

[0031] Step S10: Provide the copper material required for manufacturing the inductor, and perform stamping and bending on the copper material to obtain multiple rows of inductor wafers. Each inductor wafer includes a "Ji"-shaped wafer unit connected in sequence.

[0032] Step S11: Place the inductor wafer into a molding die, fill it with magnetic powder, and press it into shape. Among them, the magnetic powder is one or more of iron silicon, iron silicon chromium, iron silicon aluminum, iron nickel, iron nickel molybdenum, and carbonyl iron.

[0033] Step S12: Place the inductor wafer that has been pressed into shape into a sintering furnace for sintering, thereby obtaining an inductor group composed of multiple inductor units.

[0034] Among them, as Figure 2 shown, by stamping and bending the copper material to obtain multiple rows of inductor wafers, each inductor wafer includes a "Ji"-shaped wafer unit connected in sequence. Specifically, each wafer unit includes a horizontal portion placed horizontally, a lower edge portion extending outward from the horizontal portion, and extension portions extending outward from the lower edge portion respectively, thereby forming a "Ji"-shaped wafer unit.

[0035] Furthermore, place the stamped inductor wafer into a molding die, fill it with powder and press it. Among them, the molding die includes a cavity for accommodating the inductor wafer, a cover plate, upper and lower punch rods, a heating unit, and a powder vibrating unit. The powder for filling needs to be granulated and then passed through a 50-mesh sieve. After the fluidity reaches 35 - 45 s, it is filled into the die for pressing into shape. Specifically, the pressing pressure is 100 - 800 Mpa. If the pressure is too high, the coil shape becomes larger and the multi-inductor coupling effect is poor; if the pressure is too low, the compacting density is low and the inductor performance is poor. Therefore, 100 - 800 Mpa is preferably selected, and at the same time, the coil deformation is avoided from affecting the coupling coefficient of the multi-path inductor. Keep the temperature at 100 - 180 °C and keep the pressure for 60 - 180 s. Using a constant pressure is beneficial to increasing the product density and strength. More specifically, the magnetic powder used can be one or a mixed powder of not less than 2 materials among iron silicon, iron silicon chromium, iron silicon aluminum, iron nickel, iron nickel molybdenum, and carbonyl iron. When actually filling the powder, the magnetic powder, clay, and high-temperature resistant silicone resin are filled in a ratio of 94 wt%: 1 wt%: 5 wt% for pressing into shape.

[0036] Even further, after molding, place the molded inductor into an atmosphere sintering furnace for sintering. The sintering temperature is between 650 - 850 °C, and the sintering time is 60 - 360 minutes. Exemplarily, sintering can be carried out by heating - holding - cooling, with a total of 6 h. Heat up to 750 °C, then hold the temperature at a high temperature stage for 120 min. Use a mixed atmosphere of nitrogen and hydrogen, and the gas flow ratio is N2:H2 = 3:1 to prevent copper from being oxidized. At the same time, avoid the oxidation of the iron-based powder, make the inductor densify, and thereby obtain an inductor group composed of multiple inductor units with high magnetic permeability (i.e., the part formed by the wafer units after pressing and sintering).

[0037] In addition, the inductor group is cut longitudinally to obtain multiple inductors. Then, the magnets of the cut inductors are impregnated with resin to increase the magnet gap and ensure the magnet strength. Finally, the magnets are painted to prevent the inductors from rusting. The terminals at the side pins of the inductors are determined, and the leakage magnetic flux is reduced. The paint covering the terminals is stripped to expose the terminals. Copper, nickel, and tin conductive materials are electroplated at the paint stripping position and connected to the exposed terminals and the magnetic core body. Specifically, as Figure 3 shown.

[0038] On the other hand, the present invention also provides a co-fired copper-magnet inductor prepared by using the above-mentioned preparation method of the co-fired copper-magnet inductor.

[0039] In summary, in the preparation method of the co-fired copper-magnet inductor in the above embodiments of the present invention, by providing the copper material required for preparing the inductor, the copper material is stamped and bent to obtain multiple rows of inductor wafers, and each inductor wafer includes a "J"-shaped wafer unit connected in sequence; the stamped and bent copper material is placed in a mold, and magnetic powder is filled and pressed into shape, where the magnetic powder is one or more of iron silicon, iron silicon chromium, iron silicon aluminum, iron nickel, iron nickel molybdenum, and carbonyl iron; the copper material pressed into shape is placed in a sintering furnace for sintering to obtain an inductor with high magnetic permeability. The leakage magnetic flux caused by the terminal bending can be reduced by the "J"-shaped copper material, reducing the electrode exposure, thereby reducing the inductor leakage magnetic flux and improving the inductor performance. It solves the problem of large leakage magnetic flux existing in the inductors in the prior art.

[0040] To facilitate the understanding of the present invention, several embodiments of the present invention will be given below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0041] Embodiment 1

[0042] This embodiment provides a preparation method of a co-fired copper-magnet inductor, and the method includes:

[0043] Providing the copper material required for preparing the inductor, and stamping and bending the copper material to obtain multiple rows of inductor wafers, and each inductor wafer includes a "J"-shaped wafer unit connected in sequence;

[0044] Putting the inductor wafers into a molding die, filling magnetic powder and pressing them into shape, where the magnetic powder is one or more of iron silicon, iron silicon chromium, iron silicon aluminum, iron nickel, iron nickel molybdenum, and carbonyl iron;

[0045] Putting the inductor wafers pressed into shape into a sintering furnace for sintering to obtain an inductor group composed of multiple inductor units;

[0046] The inductor group is cut in the longitudinal direction to obtain a multi-channel inductor, and then the magnets of the cut inductors are impregnated with resin, and finally the magnets are spray-painted;

[0047] Identify the terminals at the side pins of the inductor and remove the paint covering the terminals to expose the terminals.

[0048] Conductive materials composed of copper, nickel and tin are electroplated at the paint stripping position and connected to the exposed terminals and the core body to obtain the final inductor.

[0049] Among them, the powder is iron silicon, the pressing pressure is 300Mpa, the holding temperature is 180℃, the sintering temperature is 700℃, the sintering time is 2h, the sintering atmosphere is a mixed atmosphere of nitrogen and hydrogen, wherein the flow ratio of nitrogen and hydrogen is 3:1, and the pressing time is 60s to 180s.

[0050] Example 2

[0051] This embodiment also provides a method for preparing a copper-magnetic co-fired inductor. The difference between the method for preparing a copper-magnetic co-fired inductor provided in this embodiment and the method for preparing a copper-magnetic co-fired inductor provided in Example 1 is that:

[0052] The sintering temperature is 780°C.

[0053] Example 3

[0054] This embodiment also provides a method for preparing a copper-magnetic co-fired inductor. The difference between the method for preparing a copper-magnetic co-fired inductor provided in this embodiment and the method for preparing a copper-magnetic co-fired inductor provided in Example 1 is that:

[0055] The sintering temperature is 850°C.

[0056] Example 4

[0057] This embodiment also provides a method for preparing a copper-magnetic co-fired inductor. The difference between the method for preparing a copper-magnetic co-fired inductor provided in this embodiment and the method for preparing a copper-magnetic co-fired inductor provided in Example 1 is that:

[0058] The magnetic powder is made of sendust.

[0059] Example 5

[0060] This embodiment also provides a method for preparing a copper-magnetic co-fired inductor. The difference between the method for preparing a copper-magnetic co-fired inductor provided in this embodiment and the method for preparing a copper-magnetic co-fired inductor provided in Example 1 is that:

[0061] The magnetic powder is made of sendust and the sintering temperature is 780℃.

[0062] Example 6

[0063] This embodiment also provides a method for preparing a copper-magnetic co-fired inductor. The difference between the method for preparing a copper-magnetic co-fired inductor provided in this embodiment and the method for preparing a copper-magnetic co-fired inductor provided in Example 1 is that:

[0064] The magnetic powder is made of sendust and the sintering temperature is 850℃.

[0065] Example 7

[0066] This embodiment also provides a method for preparing a copper-magnetic co-fired inductor. The difference between the method for preparing a copper-magnetic co-fired inductor provided in this embodiment and the method for preparing a copper-magnetic co-fired inductor provided in Example 1 is that:

[0067] The magnetic powder is made of iron silicon chromium and the sintering temperature is 780℃.

[0068] Example 8

[0069] This embodiment also provides a method for preparing a copper-magnetic co-fired inductor. The difference between the method for preparing a copper-magnetic co-fired inductor provided in this embodiment and the method for preparing a copper-magnetic co-fired inductor provided in Example 1 is that:

[0070] The magnetic powder is made of iron silicon chromium and the sintering temperature is 800℃.

[0071] Example 9

[0072] This embodiment also provides a method for preparing a copper-magnetic co-fired inductor. The difference between the method for preparing a copper-magnetic co-fired inductor provided in this embodiment and the method for preparing a copper-magnetic co-fired inductor provided in Example 1 is that:

[0073] The magnetic powder is made of iron silicon chromium and the sintering temperature is 850℃.

[0074] Please refer to the following Table 1, which shows the parameters corresponding to the above-mentioned embodiments 1-9 of the present invention. As shown in the following Table 1, it should be noted that in order to ensure the accuracy of the experiment, the other process parameters in the above-mentioned embodiments are consistent.

[0075] Table 1

[0076]

[0077] It can be clearly seen from Examples 1 to 3 that as the sintering temperature increases (from 700°C to 850°C), the inductance increases progressively, which may be because the powder microstructure can be better optimized at high temperature, thereby increasing the inductance;

[0078] It can be clearly seen from Examples 1 to 9 that the coupling coefficient generally shows an increasing trend at different sintering temperatures, but this trend is not absolute and there are some fluctuations. It is mainly manifested that the coupling coefficient increases from 700 °C to 800 °C, but decreases at 850 °C. This may be because at high sintering temperatures, the grains of the material are too large or an uneven structure is generated, resulting in a reduction in the magnetic coupling effect.

[0079] In summary, in the embodiments of the present invention, the copper material required for manufacturing the inductor is provided, and the copper material is stamped and bent to obtain a multi-row inductor sheet. Each inductor sheet includes a sheet unit in the shape of a "ji" character connected in sequence; the stamped and bent copper material is placed in a mold, filled with magnetic powder and pressed into shape, wherein the magnetic powder is one or more of iron silicon, iron silicon chromium, iron silicon aluminum, iron nickel, iron nickel molybdenum, and carbonyl iron; the copper material pressed into shape is placed in a sintering furnace for sintering, thereby obtaining an inductor with high magnetic permeability. The leakage magnetic flux caused by the terminal bending can be reduced by the "ji"-shaped copper material, reducing the exposure of the electrodes, thereby reducing the inductor leakage magnetic flux and improving the inductor performance. The problem of large leakage magnetic flux existing in the inductor in the prior art is solved.

[0080] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. A method for preparing a copper-magnetic co-fired inductor, characterized in that: The method includes: Providing the copper material required for preparing the inductor, stamping and bending the copper material to obtain multiple rows of inductor wafers, and each inductor wafer includes a wafer unit in a "ji" shape connected in sequence; Putting the inductor wafer into a forming die, filling it with magnetic powder and pressing it into shape, wherein the magnetic powder is one or more of iron silicon, iron silicon chromium, iron silicon aluminum, iron nickel, iron nickel molybdenum, and carbonyl iron; Putting the inductor wafer that has been pressed into shape into a sintering furnace for sintering to obtain an inductor group composed of multiple inductor units.

2. The method for preparing the copper-magnetic co-fired inductor according to claim 1, characterized in that: The pressure for pressing into shape is 100 Mpa to 800 Mpa.

3. The method for preparing the copper-magnetic co-fired inductor according to claim 1, characterized in that: The temperature for pressing into shape is 100 °C to 180 °C, and the time is 60 s to 180 s.

4. The method for preparing the copper-magnetic co-fired inductor according to claim 1, characterized in that: Filling magnetic powder, clay, and high-temperature resistant silicone resin in a ratio of 94 wt%: 1 wt%: 5 wt% for pressing into shape.

5. The method for preparing the copper-magnetic co-fired inductor according to claim 1, characterized in that: The sintering temperature is 650 °C to 850 °C.

6. The method for preparing the copper-magnetic co-fired inductor according to claim 5, characterized in that: The sintering time is 60 min to 360 min.

7. The method for preparing the copper-magnetic co-fired inductor according to claim 1, characterized in that: The sintering atmosphere is a mixed atmosphere of nitrogen and hydrogen, and the flow rate ratio of nitrogen to hydrogen is 3:

1.

8. The method for preparing the copper-magnetic co-fired inductor according to claim 1, characterized in that: After the step of putting the inductor wafer that has been pressed into shape into a sintering furnace for sintering to obtain an inductor group composed of multiple inductor units, it further includes: Cutting the inductor group in the longitudinal direction to obtain multiple paths of inductors, then impregnating the magnets of the cut inductors with resin, and finally painting the magnets.

9. The method for preparing the copper-magnetic co-fired inductor according to claim 8, characterized in that: After the step of cutting the inductor group in the longitudinal direction to obtain multiple paths of inductors, then impregnating the magnets of the cut inductors with resin, and finally painting the magnets, it further includes: Determining the terminals at the side pins of the inductor, and performing paint stripping treatment on the paint covering the terminals to expose the terminals; Electroplating a conductive material composed of copper, nickel, and tin at the paint stripping position to connect with the exposed terminals and the magnetic core body.

10. A copper-magnetic co-fired inductor, characterized in that: Prepared by using the preparation method of the copper-magnetic co-fired inductor according to any one of claims 1 to 9.

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