Laminated power inductor with high interlayer voltage resistance and preparation method thereof

Abstract

The invention relates to the technical field of electronic components, in particular to a laminated power inductor with high interlayer voltage resistance and a preparation method of the laminated power inductor. According to the laminated power inductor with the high interlayer pressure resistance, an iron-based soft magnetic alloy material is adopted as a magnet part of a device, and the iron-based soft magnetic alloy material comprises an iron-silicon-chromium alloy, an iron-nickel alloy, an adhesive, a dispersing agent and a plasticizer; the iron-silicon-chromium alloy contains 88%-94% of iron element, 1%-6% of silicon element and 0.5%-6% of Cr element, the iron-nickel alloy contains 45%-55% of iron element, and the soft magnetic material contains 45%-55% of nickel element. The invention has the beneficial effects that the iron-based magnetically soft alloy material is adopted, so that the rust resistance and the inter-layer pressure resistance are improved. The manufacturing steps are simple and easy to implement, and the product is excellent in performance.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic components, and in particular to a multilayer power inductor with high inter-layer voltage resistance and a preparation method thereof. Background Art

[0002] In recent years, the application of power electronics technology in power systems has become more and more extensive and in-depth. Among the many types of power electronic equipment, power supply is one of them, and its performance and functional requirements are getting higher and higher. As the core component of the switching power supply, the power inductor, the quality of its electrical parameter characteristics largely determines the efficiency and reliability of the power supply. Power inductors are mainly divided into winding type and stacked type. The stacked power inductor is made using multi-layer printing technology and stacked production process. It is smaller in size than the winding chip inductor and is a key product developed in the field of inductor components.

[0003] At present, multilayer power inductors are usually made of soft magnetic alloy materials, which are composed of iron, silicon, aluminum, nickel and other materials. The surface of soft magnetic alloy materials is easily oxidized, which leads to rust. Rust will cause the mechanical strength of the inductor to decrease. It is easy to be damaged when damaged by external force, which can easily cause failure in use. It will also affect the distribution and strength of the magnetic field, and then affect the inductance value of the product.

[0004] In addition, in practical applications, the interlayer withstand voltage characteristics of power inductors are critical to ensure the safe operation of circuits. For example, in DC-DC converters, power inductors need to be able to withstand rapidly changing voltages without causing interlayer short circuits, which could cause circuit failure or damage.

[0005] Therefore, there is an urgent need to develop a power inductor with high inter-layer pressure resistance and excellent anti-rust performance. Based on the above two problems, the present invention innovatively insulates and coats the raw tape made of soft magnetic alloy material to provide a laminated power inductor with high mechanical strength, small size and not easy to oxidize, as well as a method for preparing a power inductor with simple steps, easy to implement and excellent performance. Summary of the invention

[0006] In order to solve the above problems, a multilayer power inductor with high mechanical strength, small size and low oxidation resistance is provided, as well as a method for preparing a power inductor with simple steps, easy implementation and excellent performance. The present invention adopts the following technical solutions.

[0007] A laminated power inductor with high inter-layer pressure resistance adopts an iron-based soft magnetic alloy material as the magnetic part of the device, wherein the iron-based soft magnetic alloy material comprises an iron-silicon-chromium alloy, an iron-nickel alloy, an adhesive, a dispersant, and a plasticizer; the iron content of the iron-silicon-chromium alloy is 88%-94%, the silicon content is 1%-6%, and the Cr content is 0.5%-6%, the iron content of the iron-nickel alloy is 45%-55%, and the nickel content of the soft magnetic material is 45%-55%.

[0008] Preferably, the fine powder particle size D50 of the iron-silicon-chromium alloy powder is between 1 and 7 um, and the coarse powder particle size D50 is between 3 and 15 um; the fine powder particle size D50 of the iron-nickel alloy powder is between 1 and 9 um, and the coarse powder particle size D50 is between 3 and 16 um.

[0009] Preferably, the iron-based soft magnetic alloy material further comprises one or more combinations of silicone oil, silane coupling agent, tetraethyl orthosilicate and sodium silicate.

[0010] A method for manufacturing a multilayer power inductor with high inter-layer voltage resistance, characterized in that: A. Use fine iron-based soft magnetic alloy powder to cast the inner electric green tape, and use coarse iron-based soft magnetic alloy powder to cast the substrate green tape; B. Punch holes in the inner electrical tape so that the inner electrical sheets can be normally connected to form a circuit after being stacked; C. Printing electrode patterns on the inner electrogenic tape using silver paste; D. Printing a coarse powder filling slurry in the area of ​​the inner electrogenic tape where the electrode pattern is not printed; E. According to the set product stacking sequence, peel off the multi-layer inner electrical tape and substrate tape, and then stack and press them together; F. Debond the laminated products; G. Sinter the product after debinding; H. Cap the sintered product.

[0011] Preferably, the thickness of the inner electro-generated tape obtained by the casting is 15-20um, and the thickness of the substrate green tape obtained by the casting is 30-50um; Preferably, the printing thickness in step C is 40-80 um.

[0012] Preferably, the printing method used in steps C and D is screen printing.

[0013] Preferably, the bar blocks obtained in step E are cut into pieces with a size of 1.4*1.2 mm.

[0014] Preferably, the debinding step of step H is to increase the temperature from room temperature to 350° C. and keep it for 1-4 hours, and the sintering step of step G is to increase the temperature to 800° C. and keep it for 2-8 hours, and then naturally decrease to room temperature.

[0015] The beneficial effects of the present invention are: 1. The present invention adopts an iron-based soft magnetic alloy material, which improves the rust-proof ability and high-rise pressure resistance of the present invention.

[0016] 2. The present invention adds silicone oil, silane coupling agent, tetraethyl orthosilicate, sodium silicate, etc. during the batching process to obtain a coated green tape, so that the resistivity of the device interlayer film is higher, and a silicon oxide film layer can be formed on the surface of the product after debinding and sintering, thereby improving the interlayer insulation withstand voltage characteristics and rust prevention performance of the device.

[0017] 3. The iron-silicon-chromium alloy powder and the iron-nickel alloy powder of the present invention are both used in a mixed manner of fine and coarse materials. The fine iron-based soft magnetic alloy powder is used for tape casting to obtain the internal electrical tape, and the coarse iron-based soft magnetic alloy powder is used for tape casting to obtain the substrate tape. This allows the present invention to have good mechanical strength and high inter-layer pressure resistance.

[0018] 4. The present invention adopts the above method for preparation, which has the advantages of simple steps and easy implementation.

[0019] 5. The present invention performs insulation coating on the green tape, and sintering and molding through the above-mentioned method is helpful to form a silicon oxide film layer with a stable and dense structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A structural schematic diagram of the present invention; Figure 2 A flow chart for the printing stacking process of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further explained below in conjunction with specific implementation cases.

[0022] Example 1.

[0023] A laminated power inductor with high inter-layer pressure resistance adopts an iron-based soft magnetic alloy material as the magnetic part of the device, the iron-based soft magnetic alloy material includes 40-50 parts by weight of iron-silicon-chromium alloy, 20-30 parts by weight of solvent, 2-10 parts by weight of adhesive, 1-5 parts by weight of plasticizer, 1-3 parts by weight of dispersant, 2-5 parts by weight of silicone oil, silane coupling agent, tetraethyl orthosilicate, and sodium silicate mixture, the iron content of the iron-silicon-chromium alloy is 88%-94%, the silicon content is 1%-6%, the Cr content is 0.5%-6%, the iron content of the iron-nickel alloy is 45%-55%, and the nickel content of the soft magnetic material is 45%-55%. The fine powder particle size D50 of the iron-silicon-chromium alloy powder is between 1-7um, and the coarse powder particle size D50 is between 3-15um; the fine powder particle size D50 of the iron-nickel alloy powder is between 1-9um, and the coarse powder particle size D50 is between 3-16um.

[0024] This embodiment also includes a method for manufacturing a multilayer power inductor with high inter-layer voltage resistance, the steps of which are as follows: A. Use fine powder of iron-based soft magnetic alloy powder as ingredients, and cast the slurry on a PET film coated with silicone oil through a casting scraper to obtain an internal electro-generated tape. Use coarse powder of iron-based soft magnetic alloy powder as ingredients, and cast the slurry on a PET film coated with silicone oil through a casting scraper to obtain a substrate tape; thus, a 15-20um internal electro-generated tape 4 and a 30-50um substrate tape 1 are obtained; B. Punch holes in the inner electrical tape so that the inner electrical sheets can be normally connected to form a circuit after being stacked; C. Printing electrode pattern 2 on the inner electrogenic tape using silver paste by screen printing; D. Printing the coarse powder filling slurry in the area of ​​the inner electro-generating belt where the electrode pattern is not printed by screen printing; Specific steps of the printing process of step C and step D (such as Figure 1 shown): Step 1: Use the substrate raw tape 1-1 to make a lower protective cover, wherein the thickness of the lower protective cover is greater than 75um and less than 150um.

[0025] Step 2: Further, a coil pattern 2-1 is printed on the substrate tape 1-1 using silver paste, wherein the silver paste includes silver powder, solvent and various additives; Step 3: Continue to print a filling layer 3-1 on the film 1-1 having the coil pattern 2-1, preferably the filling layer does not cover the coil pattern; Step 4: Further, the coil pattern 2-2 is printed on the punched inner electro-generating tape 4-1 using silver paste, and the conductive through hole 5a ensures the connection between the conductive coils 2-1 and 2-2; Step 5: Continue printing a filling layer 3-2 on the membrane 4-1 having the coil pattern 2-2; Step 6: Further, repeating steps 4 to 5, using silver paste to print the coil pattern 2-3 on the punched inner electrogenerated tape 4-2, the conductive through hole 5b ensures the connection between the conductive coils 2-3 and 2-2, and continuing to print the filling layer 3-3 on the diaphragm 4-2 that has completed the coil pattern 2-3, and then using silver paste to print the coil pattern 2-4 on the punched inner electrogenerated tape 4-3, the conductive through hole 5c ensures the connection between the conductive coils 2-3 and 2-4, and continuing to print the filling layer 3-4 on the diaphragm 4-3 that has completed the coil pattern 2-3; Until the design is completed.

[0026] Step 7: Use the substrate raw tape 1-2 to make an upper protective cover, wherein the thickness of the upper protective cover is greater than 75um and less than 150um.

[0027] Step 8: The lamination sequence is determined according to the electrode pattern, in order to connect these electrode patterns into a complete circuit. The laminator grabs the sheets in a pre-set sequence to obtain a small pressure pressed block; Step 9: Cut the bar blocks obtained in step E into 1.4*1.2mm sizes; Step 10: Debind the laminated product by heating the temperature from room temperature to 350°C and keeping it for 1-4 hours; Step 11: Sinter the debinded product. After step G, heat it up to 800°C and keep it for 2-8 hours, then naturally cool it down to room temperature. Step 12: The sintered product is sealed so that the external terminal electrode 6 and the internal coil form a loop.

[0028] Example 2.

[0029] The iron-based soft magnetic alloy material described in Example 2 includes 40-50 parts by weight of iron-nickel alloy powder, 20-30 parts by weight of solvent, 2-10 parts by weight of binder, 1-5 parts by weight of plasticizer, 1-3 parts by weight of dispersant, 2-5 parts by weight of silicone oil, silane coupling agent, tetraethyl orthosilicate, and sodium silicate mixture, and the rest is the same as Example 1 Comparative Example 1: No other additives were added during the preparation of the ingredients in Comparative Example 1, and the rest was the same as in Example 1.

[0030] Comparative Example 2: No other additives were added during the preparation of Comparative Example 2, and the remaining steps were the same as those of Example 2.

[0031] The present invention adopts an iron-based soft magnetic alloy material to improve the rust prevention ability and high-layer pressure resistance of the present invention. The present invention obtains a coated raw tape by adding silicone oil, silane coupling agent, tetraethyl orthosilicate, sodium silicate, etc. during the batching process, so that the resistivity of the device interlayer film is higher. After debinding and sintering, a silicon oxide film layer can be formed on the surface of the product, thereby improving the interlayer insulation pressure resistance and rust prevention performance of the device. The iron-silicon-chromium alloy powder and the iron-nickel alloy powder of the present invention are both mixed with fine materials and coarse materials. The fine powder of the iron-based soft magnetic alloy powder is used to cast the internal electric raw tape, and the coarse powder of the iron-based soft magnetic alloy powder is used to cast the substrate raw tape, so that the present invention has good mechanical strength and high-layer pressure resistance. The present invention adopts the above method for preparation, which has the advantages of simple steps and easy implementation. The present invention performs insulation coating on the raw tape, and sintering and molding in the above method helps to form a silicon oxide film layer with a stable and dense structure.

Claims

1. A multilayer power inductor with high inter-layer withstand voltage, characterized in that: An iron-based soft magnetic alloy material is used as the magnetic part of the device, and the iron-based soft magnetic alloy material includes an iron-silicon-chromium alloy, an iron-nickel alloy, an adhesive, a dispersant, and a plasticizer; the iron content of the iron-silicon-chromium alloy is 88% to 94%, the silicon content is 1% to 6%, and the Cr content is 0.5% to 6%, the iron content of the iron-nickel alloy is 45% to 55%, and the nickel content of the soft magnetic material is 45% to 55%.

2. The multilayer power inductor with high inter-layer voltage resistance according to claim 1, characterized in that: The fine powder particle size D50 of the iron-silicon-chromium alloy powder is between 1 and 7 um, and the coarse powder particle size D50 is between 3 and 15 um; the fine powder particle size D50 of the iron-nickel alloy powder is between 1 and 9 um, and the coarse powder particle size D50 is between 3 and 16 um.

3. The multilayer power inductor with high inter-layer voltage resistance according to claim 1, characterized in that: The iron-based soft magnetic alloy material also includes one or more combinations of silicone oil, silane coupling agent, ethyl orthosilicate and sodium silicate.

4. A method for manufacturing a multilayer power inductor with high inter-layer withstand voltage according to claim 2 or 3, characterized in that: The inner electric green tape is obtained by tape casting with fine powder of iron-based soft magnetic alloy powder, and the substrate green tape is obtained by tape casting with coarse powder of iron-based soft magnetic alloy powder; Punch holes in the inner electrical tape so that the inner electrical sheets can be normally connected to form a circuit after being stacked; Printing electrode patterns on the inner electrogenic tape using silver paste; Printing a coarse powder filling slurry on an area of ​​the inner electrogenic tape where no electrode pattern is printed; According to the set product stacking sequence, the multi-layer inner electrical tape and substrate tape are peeled off and then stacked and pressed together; Debonding of laminated products; Sintering the debinding product; The sintered product is capped.

5. The method for manufacturing a multilayer power inductor with high inter-layer voltage resistance according to claim 4, characterized in that: The thickness of the inner electro-generated tape obtained by the casting is 15-20 um, and the thickness of the substrate green tape obtained by the casting is 30-50 um.

6. The method for manufacturing a multilayer power inductor with high inter-layer voltage resistance according to claim 5, characterized in that: The printing thickness in step C is 40-80um.

7. The method for manufacturing a multilayer power inductor with high inter-layer voltage resistance according to claim 6, characterized in that: The printing method used in steps C and D is screen printing.

8. The method for manufacturing a multilayer power inductor with high inter-layer voltage resistance according to claim 7, characterized in that: The bar blocks obtained in step E are cut into pieces with a size of 1.4*1.2 mm.

9. The method for manufacturing a multilayer power inductor with high inter-layer voltage resistance according to claim 7, characterized in that: The debinding step of step H is to increase the temperature from room temperature to 350°C and keep it for 1-4 hours, and the sintering step of step G is to increase the temperature to 800°C and keep it for 2-8 hours, and then naturally drop to room temperature.

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