SU62270A1 - Electrolytic galvanizing method - Google Patents

Description

The use of cyanide electrons for galvanic galvanizing makes it difficult for the body1, that zinc anodes are usually dissolved with the formation of sludge.

Particles of anodic oxide; o. Weighed in the electrolyte cause the appearance of roughness of the cathodic zinc precipitate and even lead to the occurrence of a dend of Ni on the cathode. growths or 1Lbk zinc.

In order to combat n.1 formation at the anode, it was used to make anodes by combining Nink with sky quantities of mercury, aluminum, and both mega / cu together.

However, this measure also turns out to be valid. However, only in acidic electrolytic cells, but in cyanic electrolytes, however, the formation of anode sludge is not established even if anodes doped with mercury and aluminum are used.

According to the invention, galvanizing irs in cyanide electrolytes. with price. elimination of the formation of m; ia.ia, anol, which is previously passively passive {by anodic inoculation at a new current density.

As e.: 1 monolith for this purpose, it can serve, for example iep. composition solution: ZnO-ЗЗгл, NaCM -81.;. HAON-69 g. G, ammonium ammonium-10 g.

In order for zinc to go into solution without 11o w1; 11 qu. Cham; to ;; ; 1.a anode to form a very thin film, 1ov.111vayuscheyuyu increase in the anodic potential to a value of about g2.8 in.

For this at the beginning. electrolysis at the anode for a short time (10-15 seconds), it is necessary to create a high current density of about 5- & adm, while the anode is passivated after a few seconds after being turned on, which is easily detected by a sudden attack

.45 62270

voltage from 1.5-2 in to 4-5 in. The anode is covered with the thinnest light brown film and an abundant release of oxygen begins on it.

After that, the anodic current density is reduced to 2-3 adm and.; P ;; these conditions lead to electrolysis.

During the electrolysis time, the anode should remain passivated. Covered with the thinnest brownish film; oxygen release should be very weak, barely noticeable. Under these conditions, the zinc anode operates at any time without much sludge formation. With a slip of a low current density or when it is turned off, the passive film at the anode dissolves in the electrolyte, the voltage on the bath drops sharply, and sludge begins to appear on the anode. When working with an electrolyte of the specified composition, the cathode current density should lie within 2-4 aldjvf at room temperature of the electrolyte. Identical cathode and anodic-current utilization factors determine the composition of the electrolyte, while the absence of particles has gone. It provides completely smooth, free from dendrites and roughness of zinc coatings.

i I redemet and h (: b ete n i

C. electrolytic method of cyg :: ovapi with the use of cyanic electrolytes, characterized in that, in order to eliminate sludge formation when dissolving the zinc anode, the latter is previously passivated by anodic purification at a current density.