SU1057995A1 - Process for manufacturing body-porous anode of electrolytic capacitor - Google Patents

Abstract

THE METHOD IS MANUFACTURED OF A VOLUME-POROUS ANODE OF AN ELECTROLYTIC CAPACITOR, which includes forming a tablet by electrolytic deposition of a valve metal on the output and annealing, which in order to reduce the leakage current of the capacitor, electrolytic deposition of the valve metal, by means of the template, the subfacial template will be applied to the output element, which will be applied by the same template, which will be applied by the target setter. 4.5-12.0 Sodium fluoride 3-8 Eutectic mixture of sodium potassium chloride The rest at a current density of 2.5-8 A / cm and mechanical output oscillation with a frequency of 15-120 Hz.

Description

SP

WITH

with

O1

The invention relates to the production technology of electronic devices and can be used in the manufacture of bulk-porous anodes of electrolytic capacitors from valve metals.

A known method of making volume-porous anodes of capacitors, including refining a valve metal by electron beam melting of ingots, hydrogenating the resulting ingots to render them brittle, grinding ingots into porous, dehydrating powders, introducing into the powder binder, forming a tablet by compressing the pores and sintering the tablet to give it mechanical strength and removing Cl3 from impurities. The disadvantages of this method are the complexity and laboriousness of producing pores. valve metal, the presence of impurities in the finished anode (binding residues), increasing leakage currents, irregular porosity of the tablet during pressing, limiting the operating frequency range.

The closest in technical essence and the achieved result is a method of manufacturing a volume-porous anode of an electrical capacitor, which includes forming a tablet by electrolytic deposition of a valve metal, for example electrophoresis, on output and annealing 2 3.

The method concludes that, from the valve metal porsy aka obtained by refining, dehydrating, grinding and dehydrating the binder and alcohol, an emulsion is obtained, from which electrophoresis is deposited on the wire lead of the metal-forming tablet, which is then melted.

When producing anodes in this way, a smaller amount of binder is used, as a result of which the anodes are not contaminated with its residues, which makes it possible to lower the sintering temperature without deteriorating the leakage currents of the capacitors. Anodes obtained by electrophoresis, have a uniform-. porosity, which allows to expand the frequency range of capacitors.

However, in this method, the source material is a valve metal powder, the complexity and complexity of which leads to their high cost, which constitutes a large part of the cost of the capacitor. In addition, the total amount of impurities containing in the original powder is not sufficiently reduced, which degrades the electrical parameters of the capacitors, in particular, increases the leakage currents.

The purpose of the invention is to reduce the leakage current of the capacitor.

This goal is achieved by the fact that, in contrast to the known method of making a volume-porous anode of an electrolytic capacitor, including forming a tablet by electrolytic deposition of a valve metal on the withdrawal and annealing, electrolytic deposition. valve metal is carried out from a melt containing, in wt.%:

Fluorobiobate

4.5-12.0

Kali Fluoride 3-8 natrzh. Eutectic Chloride Blend

The rest is potassium and sodium

at a current density of 2.5-8 A / cm and mechanically (output oscillation with a frequency of 15-120 Hz.

j Anodes of electrolytic capacitors are made by electrolytic deposition of niobium on the cathode of a bath of 0.8 mm diameter tantalum wire, which then serves as the anodic lead of the Anodiss capacitor of the electrolytic bath (with an expenditure of & L9L electrode) niobium tin.

To obtain volume-porous anodes of capacitors, electrolytes are prepared with the following component content, wt%: potassium fluoride 4,5, 8.0, and 12.0, sodium 3.0, 5.0, and 8.0 and a eutectic mixture of potassium and sodium chorides , supplement a roll up to 100% portion in each melt. Deposition is carried out at 750 C. For each melt, deposition is carried out at 3 current densities — 2.5 A / cm% 4.0 A / cm and 8.0 A / cm and 3 frequencies of vibration of the cathode — 15 Hz. 50 Hz and 120 Hz. After receiving on the wire leads, the anole tablets of capacitors are shed from the residual electrolyte in distilled water and subjected to vacuum annealing at 1600 ° C.

Further manufacture of capacitors is carried out according to the current technological process.

The electrical parameters of the capacitors obtained under different conditions are presented in Table. one.

The concentration in the potassium fluorobiobate melt determines the concentration of the valve metal ions. The minimum amount of fluorniobate (4.5 wt.% Corresponds to the minimum amount of metal ions (1.5 wt.% |, And the maximum amount of fluorniobate (12 wt.% / Maximum amount (3.8 May.%). As

can be seen from the table. 1 a decrease in the concentration of metal ions of less than 1.5 wt.% Leads to a decrease in the specific capacitance of the anode capacitors, regardless of the frequency of mechanical vibrations. and current density. Increasing the concentration above 3.8 wt.% Leads to a deterioration in the mechanical strength of the anodes (the precipitate falls off).

The percentage of the remaining components determines the minimum melting point of the electrolyte, providing a precipitate with a well-branched surface, at which it is possible to obtain the maximum capacity per gram of metal to be deposited.

In addition, the resulting precipitate with a highly developed surface contributes to the deposition process with high current density at the cathode. The use of vibration at a certain frequency allows to obtain a good mechanical adhesion of the sediment to the wire lead 4 (base) and to improve the delivery of ions of the deposited metal to the electrode.

Maintaining the concentration of niobium ions in the melt is due to the dissolution in the process of electrolysis of metallic niobium (for example, tin, which is used as the anode of the electrolytic bath.

As can be seen from the table. 1 capacitors, in which the anodes are obtained at

current density 4 A / cm 2, vibration frequency 50 Hz and ion concentration of niobium 3.8 wt.% have the best electric parameters.

An experimental batch of capacitors of nominal 20V "1 microfarad, having anodes, made by the proposed method, tested maximum operating load for 2000 hours.

The test results for electric meters and capacitors are presented in table. 2

As can be seen from table 2, capacitors with anodes made by the proposed method are highly reliable.

This method of manufacturing anodes of capacitors allows simultaneously with the logging of the anodes of the capacitors to produce refining valve metals.

In tab. 3 shows cf.: pvnitelny data on the amount of impurities in the anodes of capacitors, obtained by the proposed and known methods.

five

The proposed method will reduce the complexity and cost of capacitors, as there is no need for the production of powders

0 valve metals, as well as to increase the percentage of yield of products by 3-4% due to the reduction of leakage currents of capacitors.

Table

4.5

15 50

120

about

15

4.5

50

120

15

4.5

50

120

15

3.17

2.5

5.92

2.04

7.94

2.72

6.06

1.2

11.39

0.8

11.61

0.5

1.1

9.88

1.47

6.74

1.06

13.51

7.5

1.07

11.60

1D1

9.35

,five

8.0

50

3.0

120

15

, 0

8.0

50

5.0

120

15

, 0

8.0

8.0

50

120

15

,five

-50

12.0

3.0

120

15

, 0

50

12.0

5.0

120

15

, 0

50

12.0

8.0

120

Continued table. one.

9.0

15.44

0.80 14.21

1.05 11.22

0.85

16,58

7.0

0.35

one

15.34

0.55

g

11.04

1.01

4.0 17.94

0.63 16.32

0.70 14.11

0.32. 18.51

5.0

0.15 16.40

0.21, 18.52

0.45 25.31

3.0

0.23 20.02

0.24 18.24

0.18

0.0 21.23

0.18 18.52

0.18

Table 2

Standards TU

ten

15

Continued table. 2

70

-25

. thirty

Claims (2)

2. French patent In 2351482, _Mr. CL H 01 G 9/05, published. 1978. 'METHOD FOR PRODUCING A VOLUME-POROUS ANODE OF AN ELECTROLYTIC CAPACITOR, comprising forming a tablet by electrolytic deposition of a valve metal to an outlet and annealing, characterized in that, in order to reduce the leakage current of the capacitor, the electrolytic deposition of the valve metal carries out a melt containing, wt.%: Potassium fluorine iiobate 4.5-12.0 Sodium Fluoride 3-8 Eutectic mixture of potassium and sodium chlorides at current density Rest 2.5-8 A / cm ^ and mechanical oscillation of the output with a frequency of 15-120 Hz.