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Low-ESR cathode of tantalum electrolytic capacitor and preparation method for cathode

A technology for tantalum electrolytic capacitors and cathodes, which is applied to the cathode of low-ESR tantalum electrolytic capacitors and its preparation field. It can solve the problems of low filling rate, large bubbles, large ESR, etc., and achieve the effect of improving electrical performance

Active Publication Date: 2019-02-01
CHINA ZHENHUA GRP XINYUN ELECTRONICS COMP ANDDEV CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Excessive surface tension of the coating liquid leads to poor wettability of the solution, and the micropores of the tantalum anode cannot be filled during impregnation. The manganese dioxide produced by the thermal decomposition of manganese nitrate has a low filling rate in the micropores of the tantalum anode, and the effective cathode area is small, which is prone to The capacitance of the capacitor is low and the ESR is large; the viscosity of the coating liquid is too high, which will lead to large bubbles generated by dehydration and thermal decomposition, cracks in the manganese dioxide film layer, rough surface of manganese dioxide, hardening, loose cathode film layer, manganese dioxide The contact resistance between layers is large, which increases the ESR and seriously affects the high-frequency electrical performance of the product

Method used

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  • Low-ESR cathode of tantalum electrolytic capacitor and preparation method for cathode
  • Low-ESR cathode of tantalum electrolytic capacitor and preparation method for cathode
  • Low-ESR cathode of tantalum electrolytic capacitor and preparation method for cathode

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preparation example Construction

[0023] The invention relates to a method for preparing a cathode of a low-ESR tantalum electrolytic capacitor, which comprises preparing a manganese dioxide layer on the surface of a tantalum block with a dielectric oxide film, and after the manganese dioxide layer is prepared on the surface of the tantalum block, the manganese dioxide After the surface of the layer is coated with a graphite layer and a silver paste layer, the finished cathode of the ESR tantalum electrolytic capacitor is obtained. The graphite layer, silver paste layer, and process processing are prior art, and will not be repeated here.

[0024] It should be noted that, in a preferred embodiment of the present invention, the tantalum block with a dielectric oxide film is produced by the following method: immerse the tantalum block in a phosphoric acid solution with a mass concentration of phosphoric acid of 0.01% to 0.08%, and apply 45V to Formation voltage of 55V generates Ta 2 o 5 The dielectric oxide fil...

Embodiment 1

[0054] 1) Select a tantalum block with a size of 1.7×3.4×3.5 (mm) to make a 16V47μF tantalum capacitor. After vacuum sintering, apply a formation voltage of 47V to a tantalum block in a phosphoric acid solution with a mass fraction of 0.03% to generate Ta 2 o 5 Dielectric oxide film, after heat treatment at 360°C, the obtained tantalum block with dielectric oxide film is changed from small to large according to the specific gravity, and the specific gravity in the manganese nitrate solution is d=1.07g / cm 3 、d=1.15g / cm 3 、d=1.25g / cm 3 、d=1.35g / cm 3 Immersion in the solution, a total of 12 times of immersion, while each immersion time 6 minutes. After each impregnation, the anode block was taken out and dried in an oven at 85°C for 6 minutes, and then thermally decomposed for 6 minutes at a temperature of 260°C, a water vapor pressure of 0.04MPa, and an oxygen mass percent concentration of 12%. Among them, every 4 times of decomposition, a supplementary forming process is pe...

Embodiment 2

[0063] 1) Select a tantalum block with a size of 3.0×5.2×5.8 (mm) to make a 20V330μF tantalum capacitor. After vacuum sintering, apply a formation voltage of 56V to a tantalum block in a phosphoric acid solution with a mass fraction of 0.03% to generate Ta 2 o 5 Dielectric oxide film, after heat treatment at 360°C, the obtained tantalum block with dielectric oxide film is changed from small to large according to the specific gravity, and the specific gravity in the manganese nitrate solution is d=1.07g / cm 3 、d=1.15g / cm3 、d=1.25g / cm 3 、d=1.35g / cm 3 Immersion in the solution, a total of 12 times of immersion, each immersion for 6 minutes. After each impregnation, take out the anode block and place it in an oven at 85°C to dry for 6 minutes, and then thermally decompose it for 6 minutes at a temperature of 270°C, a water vapor pressure of 0.03MPa, and an oxygen mass percent concentration of 12%. Do a supplementary forming process once at a time.

[0064] 2) Immerse the anode ...

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Abstract

The invention relates to a low-ESR cathode of a low-ESR tantalum electrolytic capacitor and a preparation method for the cathode, and relates to the technical field of tantalum capacitor manufacturing. The preparation method comprises the steps: preparing a manganese dioxide layer on the surface of a tantalum block with a dielectric oxidation film, wherein the manganese dioxide layer is prepared through a method which comprises the steps: performing the dipping of the tantalum block in manganese nitrate solution with different specific gravities for many times, performing the thermal decomposition to obtain a first cathode, performing the dipping of the first cathode in outer mixed solution, performing the decomposition for many times under the temperature from 250 DEG C to 280 DEG C, performing the reinforcement processing, and performing the dipping and thermal decomposition in the outer mixed solution to obtain the electrode, wherein the outer mixed solution is prepared through adding a dispersing agent and a viscosity reducer to the manganese nitrate solution. The method enables the surface of the tantalum block to form compact manganese dioxide shaped like popcorn, thereby completing the manufacturing of the low-ESR electrode, and improving the high-frequency electrical performance of the tantalum electrolytic capacitor.

Description

technical field [0001] The invention relates to the technical field of tantalum capacitor manufacturing, and in particular to a cathode of a low-ESR tantalum electrolytic capacitor and a preparation method thereof. Background technique [0002] In recent years, all kinds of electronic products for military and civilian use are developing in the direction of short, small, light and thin, which requires the miniaturization of electronic components supporting it. The remarkable advantages of solid electrolytic tantalum capacitors are large capacity and easy to make small and chip components. In addition, they also have the characteristics of low ESR, low leakage current, low loss, long life, and good stability. Therefore, they are widely used in various electronic products. It has been widely used, especially in the fields of national defense such as aviation, aerospace, missiles, satellites, and radar. [0003] In the production process of solid electrolyte tantalum capacitor...

Claims

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Application Information

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IPC IPC(8): H01G9/042H01G9/048H01G9/15
CPCH01G9/0425H01G9/048H01G9/15
Inventor 曹煊周建新潘齐凤鄢波李美霞王富权
Owner CHINA ZHENHUA GRP XINYUN ELECTRONICS COMP ANDDEV CO LTD
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