SU603709A1 - Silver-plating electrolyte - Google Patents

Description

Moreover, as a derivative of thiourea it contains a compound of the general formula

s

fH -

2 R-CH2CH20H - // 5 -CH2 a also a compound of the general formula

R-HH- -KH-CHjOH;

gWe B-H; HOCH2.

The technology of prepared electrolyte is very simple. Silver nitrate is added to the additive in a solution of nitric acid in solid form. Both solids and hx concentrated solutions can be used for adjustments.

The deposition of silver on copper from nitrogen: the electrolyte logo can be carried out both electrolytically and by contact methods. The contact method is particularly simple, convenient, and consists in the fact that copper is immersed in a bath of an electrolyte, before it is degreased and pickled in a 5O% solution of nitric acid for a second.

The copper substrate is immediately covered with a shiny silver layer. With increasing deposition time by contact

(.1O-15O min) the thickness of the coating grows and up to a thickness of 6 microns the sediments remain smooth, shiny, well adhered to the substrate. Such coatings can be recommended as decorative sludge for imparting special properties (e.g., electrical conductivity) to parts operating under 6 mild conditions. Contact deposition can be used for pretreatment before cyanide silvering of parts.

Silver is deposited on copper by electrolytic method at a pfH of 0.5-1.1 room temperature and current densities O, 1-O, 4 A / dm with soluble silver anodes, which are not passivated during electrolysis. The duration of the process is 1O-2O minutes. Electrolytic coatings are more dense, uniform, well adhered to the copper substrate, as compared to contact surfaces, shining d 6 mm thick. .

With an increase in precipitation time, silver precipitates become opaque with a dark smoke, the thickness of the coatings practically does not depend on the cathode current density. current limit.

An increase in the concentration of silver nitrate in a solution of more than 5 g / l leads to the rapid formation and growth of dendrites on a copper substrate. However, npji of elevated concentrations (from 10 to 2OO g / l), electrochemical deposition of light, smooth, fine-crystalline, silver-bonded silver deposits on noble metals, in particular, on silver, is possible. This will make it possible to significantly intensify the process of silver deposition, if it is necessary to obtain thick precipitates due to the high content of silver nitrate AgNO in the electrolyte and an increase in cathode current density to 0.5–5 A / dm. The best condition. Electrolyte is deposition at a constant potential, somewhat more negative than the stationary potential of copper in a given electrolyte, for example, Yu, 2O-0.28O V relative to the normal hydrogen electrode of the comparison.

The table shows examples of the composition of electrolytes.

Derivative tiomoch evins common form ({uly

/ IN-CH2 "t,

.

where fl-CH2CH20H}

1-2- (Oxyethnl) -gvksagi.tsro-1, 3,5-griaain-4- thion

-ABOUT

The proposed electrolyte is non-toxic, easy to prepare, use and adjust. The cost of 10 liters of electrolyte is 14.64 rubles.

Claims (4)

1. Silver plating electrolyte containing silver nitrate, nitric acid and an organic additive, characterized in that, in order to obtain shiny coatings directly on copper and its alloys by contact or electrolytic extension of the table WHOSE deposition, as an organic additive, it contains a derivative of thiourea at a ratio of components, g / l: Silver Nitrate1-5 Nitric acid 8-ZO Derived thiourea, 2-O, 6. 2. The electrolyte according to claim 1, which is based on the fact that, as a derivative of thiourea, it contains a compound of the general formula:., MxKH —CH2  lp 5  KH-CH27-- where R- (IH2CH20H; ( -dH 7 3. The electrolyte according to claim 1, which is based on the fact that, as a derivative of thiourea, it contains a compound of the general formula: B-HH-C- "H-CH bH, jl 5 - , g9e vn} NOYN. Sources of information taken into account in the examination: 8 1. Copyright certificate № 312-e92j Cl, C 3/46, 1971. 2, Copyright certificate № 457754, cl. C 25 t) 3/46, 1975. 3. Copyright certificate № 411156, cl. C 25 -I 3/46, 1974. 4. Copyright certificate Kj 461158, cl. C 2516 3/46, 1976.