SU1184875A1 - Device for power supply of electroplating baths with pulsing current - Google Patents

Description

The invention relates to electroplating, 'specifically to devices for electroplating baths non-constant periodic currents in unsteady electrolysis modes for use in electroplating shops of enterprises of almost all sectors of the national economy, and can be used to obtain a number of metals (with different areas of the surface to be coated), precipitation and oxide films with improved physicomechanical properties.

The aim of the invention is to reduce dendritic formation, hydrogenation and internal stress of sediments by obtaining a bipolar alternating bursts of current pulses.

FIG. 1 shows a block diagram of the proposed device, FIG. 2 diagrams explaining his work.

The device contains an alternating voltage source, three independently adjustable rectifiers 1, 2 and 3, three thyristor-capacitor ₍ channels, which, in turn, consist of current-limiting elements 4, 5 and 6, charging thyristors 7, 8 and 9, capacitive drives 10 , 11 and 12, bit thyristors 13, 14 and 15, switching thyristors 16, 17 and 18 and thyristors 19 and 20. current reverser. The load of the thyristor-capacitor channels is a galvanic bath 21. In addition, the device contains a generator of 22 mode pulses, adjustable generators 23, 24 and 25 hours volts, as well as adjustable delays 26-31, addition logic element 32 and matching elements 33 - 43, the outputs of which are connected to the control electrodes of the corresponding thyristors. The matching elements are the trigger pulse amplifiers used in this device. , can be built on both analog and digital principle.

The principle of operation of the device is as follows.

From the outside. industrial AC network single-phase or three-phase voltage supplied to independently adjustable rectifiers

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1, 2 and 3. Rectified and smoothed by them voltage goes through current-limiting elements 4, 5 and 6 to charging thyristors 7, 8 and 9

5 thyristor-capacitor channels. Generators 23, 24 and 25, frequencies

which are very different from each other (Fig. 2 a, & and E), work alternately. Their work determines

, Generator 22 mode pulses

(Fig. 2 1 - 0), which forms the duration of both cathode and anode packs of a bipolar pulsed current. The resulting packs unlocking

15 pulses are alternately fed to the control electrodes (via matching elements) of the charging thyristors 7, 8 and 9 of the corresponding thyristor-capacitor channels. Cro20 packs. These same pulses

alternately served on two connected in series delay 26 and 27 of the respective channels.

The device works as follows.

25 way.

When the triggering pulse arrives at time ί ₀ (Fig. 2k) at the control electrode of the charging thyristor 7 and as a result of the opening of the latter (all other thyristors are closed), charge occurs through the current-limiting element 4 of the capacitive storage .10 (Fig. 2x).

As the latter charges, the current flowing through the thyristor decreases, and at a current less than the current holding of the thyristor, the latter will close. A delay 28, delaying the unlocking signal for a time determined by the constant charge of the circuit (i.e., the capacitance of the storage device 10 and the inductance of element 4, as well as the recovery time of the locking properties of the thyristor 7) controls the opening of the discharge thyristor 13. When the unlocking signal is applied at time ί, (Fig. 2l, y) to the discharge thyristor 13 and thyristor 20 reverse current as a result of their opening 50 pre-charged capacitive storage 10 begins to discharge into the electroplating bath 21, forming a working polarizing pulse with straight polarity (Fig. 2 x, i). 55 After a specified (adjustable delay 31) period of time at time 1 ₂ (Fig. 2m), a triggering pulse is applied to the commutation

thirty

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thyristor 18, which

shunts capacitive storage 10 and thereby forms the leading edge of the polarizing pulse (Fig. 2k, s)

The flow time of an odd pack of 5

pulses of the cathode component of the operating current is set by the generator of regime pulses (Fig. 2?, *).

At time

unlocking impulse on the manager 10

thyristor electrode 9 (Fig. 2p). As a result of the opening of this thyristor, the capacitive storage device 12 is charged through the current-limiting element 6 (Fig. 2h). After a time, 15

determined by the delay 26 (time ί.η), the discharge thyristor 15 and the current-reverse thyristor 19 are opened (Fig. 2c, <p). The previously charged capacitive drive 12 discharges 20 to the electroplating bath 21, thus forming a working polarizing pulse of reverse polarity (FIG. 2H, W). After a time interval defined by the delay 30 (time 25 of FIG. 2t), the thyristor 16 opens (FIG. 2T ), thereby forming the leading edge of the working pulse (FIG. 2 h. 1). The flow time of the anode component of the operating current, 3θ, as well as the flow time of the previous burst, is controlled by a mode pulse generator (FIG. 2e, c).

The formation of an even pack of pulses of the cathode component of the operating current is similar to that considered. In this case, the following elements of the device work alternately: moment of time £ _m _, "+" of the rectifier 2, current limiting element 5, charging thyristor 8, capacitive storage 11;

rectifiers 2 (fig. 2n, c, s) ', time instant capacitive storage 11, discharge thyristor 14, galvanic bath 21, current-reversing thyristor 20, capacitive storage 11 (fig. 2o, 1 |, c, s); point in time capacitive drive 11, switching thyristor 17, capacitive drive 11 (Fig. 2 l, C, ω).

Then (instant of time £ _k ., ·,,

£ _К4 ,) a pack of impulses of the anode component of the operating current is formed with the participation of the elements: adjustable

the rectifier 3, the current-limiting element 6, the charging thyristor 9, the capacitive drive 12, the discharge thyristor 15, the thyristor 19 of the current reverser and the switching thyristor 16 (Fig. 2p, c, <p, t, h, and).

Packs of polarizing pulses, significantly differing in frequency and duration of the packs themselves, replace each other on the load in accordance with the considered period of operation of the device (Fig. 21c).

The use of the proposed device in comparison with the known provides bipolar pulsed current, alternating bursts of pulses; the ability to independently regulate both the duration of the anodic and cathodic pulse packs, as well as their amplitude, frequency, duration, as well as the ability to regulate the average current not only by the amplitude, frequency, duration of the pulses and the form of their filling, but also by the duration of the flow of the anodic and cathodic packs,

Using this device, alternating metal layers adjustable in thickness are obtained, which differ sharply from each other in phase composition, structure, texture, and physicomechanical properties, as well as coatings with both good adhesion, high temporal resistance, and reduced internal stress. .

At the same time, dendritogenesis is reduced to a minimum and the hydrogen content in precipitation decreases.

A comparison of the physicomechanical properties of nickel coatings obtained using a known device and that of a Watts type electrolyte shows that internal stresses decrease from 500 to 300 MPa; the porosity also decreases from 0.01 pores / cm ² to zero in thicknesses up to 1 μm, the use of this device allows to exclude dendritogenesis (on contact details or details of a complex configuration); reduce the concentration of hydrogen in precipitation.

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Claims (1)

DEVICE FOR POWER SUPPLY OF GALVANIC BATHTUBS WITH PULSE CURRENT, consisting of galvanic bath, a source of alternating voltage, adjustable rectifier, current-limiting element and p. thyristor-capacitor channels with discharge thyristors, characterized in that, in order to reduce dendritogenesis, hydrogenation and internal precipitation voltages by obtaining a bipolar with alternating current bursts of current pulses, it is equipped with a current reverser, the thyristors of which together with the discharge thyristors of the thyristor-capacitor channels form a bridge , in the diagonal of which 9 is included galvanic bath. 00 eo m 01 > 1 11