JPS59124119A - Method of producing solid electrolytic condenser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a method for manufacturing a solid electrolytic capacitor.

Conventionally, solid electrolytic capacitors using a valve metal such as tantalum as an anode body have been manufactured by immersing the anode body in a solution or melt of manganese nitrate or the like to form a semiconductor layer of manganese dioxide or the like, and then immersing the anode body in a solution or melt of manganese nitrate, etc. A method of thermal decomposition is used. However, with this method, N generated during thermal decomposition
For Ox gas ICs, the semiconductor layer is not a homogeneous, uniformly thin layer, but is porous and has poor adhesiveness. Therefore,
This has the disadvantage that the resistance of the semiconductor layer itself and the contact resistance with the carbon layer provided on the semiconductor layer become large, resulting in large losses in the capacitor.

It is also known that a homogeneous and uniform thin layer is formed when pyrolysis is carried out in a steam atmosphere;
If the temperature exceeds 0℃, manganese dioxide etc. will fly out and adhere to the tantalum etc. lead wire drawn out from the anode body, and when welding this lead wire and the terminal, sparks will fly off and the work will be dangerous. This has the disadvantage of being difficult to use, and also has the disadvantage of generally increasing leakage current.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a solid electrolytic capacitor which can improve the above-mentioned drawbacks, is easy to work with, and can improve various characteristics such as loss and leakage current.

In order to achieve the above object, the present invention immerses a sintered body after forming an anodized film in a semiconductor mother liquor, and then heats the body at a temperature of 200°C.
Pyrolysis in a steam atmosphere at ~350°C, then at a temperature of 20°C.
The present invention provides a method for manufacturing a solid electrolytic capacitor, characterized in that a semiconductor layer is provided by thermal decomposition in a steam atmosphere at 0° C. or lower.

In addition, in order to achieve the above object, the present invention provides that after immersing a sintered body with an anodized film formed thereon in a semiconductor mother liquor and thermally decomposing it in a steam atmosphere at a temperature of 200°C to 350°C, Solid electrolysis characterized by forming a semiconductor layer by immersing it in a semiconductor mother liquor to which at least one type of reducing agent such as ammonium nitrate, urea, formic acid, and alcohols has been added and thermally decomposing it in a steam atmosphere at a temperature of 200°C or less. A method for manufacturing a capacitor is provided.

Furthermore, in order to achieve the above-mentioned object, the present invention involves immersing the sintered body after forming the anodic oxide film in a semiconductor mother liquor.
It is thermally decomposed in a steam atmosphere of 00℃ to 350℃, and then thermally decomposed in a steam atmosphere of 200℃ or less with a small amount of reducing agents such as ammonium nitrate, urea, formic acid, and alcohols. The present invention provides a third method for manufacturing solid electrolytic capacitors characterized by providing a layer.

That is, in the present invention, the semiconductor layer is formed by immersing the sintered body after forming the anodic oxide film in a semiconductor mother liquor such as manganese nitrate and thermally decomposing it in a temperature range of about 200°C to 350°C. A semiconductor layer made of fine particles such as manganese dioxide is formed inside the sintered body. At this stage, the semiconductor layer is formed inside the sintered body, so the impregnated semiconductor liquid does not scatter. Then, the sintered body is
Steam containing at least one type of reducing agent such as normal or ammonium nitrate at a temperature of 200°C or less after being immersed in a semiconductor mother liquor containing at least one type of reducing agent such as normal or ammonium nitrate, urea, formic acid, and alcohols. It is thermally decomposed in an atmosphere to form a semiconductor layer even outside the sintered body. At this time, the low thermal decomposition temperature prevents the semiconductor liquid from scattering, making subsequent welding of the terminals easier.
Also, since a homogeneous and uniform semiconductor layer is formed on the outside, loss is improved as a whole and leakage current characteristics are improved.

Note that the reducing agent has the effect of accelerating the thermal decomposition reaction in low-temperature thermal decomposition, thereby improving production efficiency.

Note that when thermal decomposition is performed in a low-temperature steam atmosphere,
Although the capacity may be slightly reduced, according to the present invention, a semiconductor layer made of fine grains can be formed inside the sintered body by performing normal high-temperature thermal decomposition in the first stage, so the capacity is still sufficient. is obtained.

Next, the characteristics of tantalum solid electrolytic capacitors with a rating of 35 V and 10 μF will be compared between those according to the present invention and those of a conventional example.

First, using tantalum powder as the valve metal, a sintered body of this powder is immersed in an aqueous phosphoric acid solution and oxidized by applying a voltage of 140 μm to form an oxide film.

Next 1. After forming the anodic oxide film, the sintered body has a concentration of 40 to 60.
% manganese nitrate aqueous solution to impregnate the liquid, then taken out and thermally decomposed in a steam atmosphere at a temperature of 230°C. Thereafter, the steps from impregnation to thermal decomposition are repeated three times. After repeating each process three times, the sintered body was made into a glass a! The semiconductor layer is immersed in a manganese nitrate aqueous solution to which a small amount of ammonium is added, and thermally decomposed in a steam atmosphere at a temperature of 190° C., and then repeated three times to form a semiconductor layer. After thermal decomposition, reconstitution is performed in an aqueous phosphoric acid solution. The subsequent steps are the same as before.
A tantalum solid electrolytic capacitor is manufactured by providing a carbon layer and a metal layer consisting of a silver layer and a solder layer.

In the conventional method, instead of soaking the sintered body twice in an aqueous manganese nitrate solution and then thermally decomposing it in a steam atmosphere at 190°C, the same conventional thermal decomposition as the previous step is repeated three times.

When we measured the initial characteristics such as capacity and jan δ of 100 pieces of each of the inventive and conventional products manufactured by the above method and calculated the average values, the results shown in Table 1 were obtained. Ta. 1J-However, the present invention has a better ta
nδ decreased by 13%, individual current decreased by 73%, and
Yoji is still the same as before, but each initial characteristic has been improved.

Further, when the moisture resistance of each of the examples with the above ratings was measured, the results shown in Table 2 were obtained. Humidity test is PC
T, temperature 120℃, 2 atmospheres, 4 HV conditions, each 2
I did 0 pieces at a time. J', that is, the capacitance change rate is 11% and the tan δ change rate is 2% compared to the conventional example according to the present invention.
The leakage current change rate was reduced by 0% and 60%, and the moisture resistance was also improved.

As described above, according to the present invention, it is possible to obtain a method for manufacturing a solid electrolytic capacitor that not only facilitates welding of terminals but also improves initial characteristics such as capacity, loss, leakage current, and moisture resistance.

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Claims (3)

[Claims] (1) In a method for manufacturing a solid electrolytic capacitor, in which an anodized film, a semiconductor layer, a carbon layer, and a metal layer are sequentially applied to a sintered body made of valve metal powder, @sintering after the formation of an extremely resistant film After the body is immersed in the semiconductor mother liquor, the temperature is 200℃.
``A method for producing a solid electrolytic capacitor, which comprises thermally decomposing it in a steam atmosphere at a temperature of 0 to 350°C, and then thermally decomposing it in a steam atmosphere at a temperature of 200°C or less to provide a semiconductor layer. (2) In a method for producing a solid electrolytic capacitor in which an anodized film, a semiconductor layer, a carbon layer, and a metal layer are sequentially provided on a sintered body made of valve metal powder, the sintered body after the anodized film is formed is mixed with a semiconductor mother liquor. Immerse it in the temperature 2oo℃~
After thermal decomposition in a steam atmosphere at 350°C, it is immersed in a semiconductor mother liquor containing a small amount of reducing agents such as ammonium nitrate, urea, formic acid, and alcohols, and heated to a temperature of 20°C.
A method for manufacturing a solid electrolytic capacitor, which comprises forming a semiconductor layer by thermal decomposition in a steam atmosphere at a temperature of 0° C. or lower. (3) In the method for producing a solid electrolytic capacitor in which an anodized film, a semiconductor layer, a carbon layer, and a metal layer are sequentially provided on a sintered body made of valve metal powder, the sintered body after the anodic oxide film is formed is Immersed in semiconductor mother liquor at a temperature of 200°C to 35°C
The semiconductor layer is formed by thermal decomposition in a hot air atmosphere at 0°C, and then thermal decomposition in a steam atmosphere at a temperature of 200°C or lower containing at least one reducing agent such as ammonium nitrate, urea, formic acid, and alcohols. Features: Manufacturing method of solid electrolytic capacitors.