SU1294878A1 - Electrolyte for deposition of tin-zinc alloy coatings - Google Patents

Abstract

The invention is intended for electrodeposition of tin-zinc alloy coatings and may find application in various fields of technology for coating components of complex configuration. The purpose of the invention is to increase the scattering ability and stability of the composition of the alloys. The electrolyte contains, g / l: tin chloride (dichloride) 20-50; zinc chloride 25-50; ammonium chloride 120-170; sodium fluoride 30-50; bortohydric - hydrogen acid (40%) 10-30; wetting agent OS-20 2-10; 2- (2-pyridyl) - benzimidazole 1-2. The decrease in the scattering ability of the electrolyte and the formation of more stable coatings is achieved by the joint introduction of hydrofluoric acid and 2- (2-pyridyl) -benzimidazole, Table 3. S (L with: INS CO 00 OS

Description

The invention relates to the electroplating of tin-zinc alloys and can be used in various fields of technology when applying coatings to parts of complex configuration.

The aim of the invention is to increase the scattering ability of the electrolyte and the stability of the composition of the alloy.

The deposition process is carried out at a current density of 100-800 A / m, temperature and pH 4.7-51.

The electrolyte is prepared as follows.

The required amount of 2- (2-pyridyl benzimidazole, sodium fluoride, tin chloride, ammonium and zinc is dissolved in pre-acidified boron hydrofluoric acid). The resulting solution is filtered, the solution of the wetting agent OC-20 is added and the volume of electrolyte is adjusted to 1 l with water.

Hydrofluoric acid enhances the electrical conductivity of the solution, but at the same time changes its pH little, thereby helping to stabilize the composition of the alloy.

2- (2-Pyridyl) -benzimidazole, adsorbed on the cathode together with OS-20, causes depolarization during the deposition of zinc and allows to obtain compact coatings of tin-zinc alloys, more stable in composition in a wide range of current densities at transmission up to 150 Ah / A of electricity, after which it is necessary to additionally introduce an additive in the amount of 0.25-0.50 g / l.

The invention is illustrated in the data table. 1-3.

Chloride tin (two-water)

Zinc chloride sodium fluoride ammonium chloride hydrochloric acid (, 19)

0

five

0

five

0

The scattering power is determined in a Moler slit cell;

The solubility of freshly deposited coatings is determined by spreading the dose of solder.

The deposition of tin-zinc alloys is carried out on samples of St. 3 steel, and for the evaluation of the consumption on stainless steel X18H10T.

As can be seen, the proposed electrolyte has a high scattering ability and allows to obtain more stable alloys.

Claims (1)

Invention Formula The electrolyte for the deposition of coatings of tin-zinc alloy containing tin chloride, zinc and ammonium, sodium fluoride, wetting agent OC-20, mineral acid and surfactant additive, characterized in that, in order to increase the scattering ability of the electrolyte and the stability of the composition of the alloys, as a mineral salt and surfactant, it contains hydrofluoric acid and 2- (2-pyridium, p) -benzimidazole, respectively, in the following ratio of components, g / l: Tin chloride two-water 20-50 Zinc chloride 25-50 Ammonium chloride 120-170 Sodium fluoride 30-50 Hydrofluoric acid (40%) 10-30 Wetting agent OC-202-10 2- (2-Pyridyl) - benzimidazole 1-2 Table i 20 25 0 20 thirty thirty 40 150 40 40 45 150 50 -50 50 170 Hydrogen fluoride Temperature, C Current density Current output,% Deposition rate µm / min .Content of zinc,% Diffusing power,% 49.1 43, i Paemity of freshly deposited coatings, Kr 1.39 1.37 Continuation of table 1 20502050 400600500800 93,294,392,493,7 1,502,321,863,02 32,729,334,933,6 53,648,649,738,3 1,411,381,361,37