SU840207A1 - Electrolyte for precipitating nickel-cobalt alloy platings - Google Patents

Description

(54) ELECTROLYTE FOR DEPOSITING COATINGS FROM NICKEL-COBALT ALLOY

It also improves the dissipative capacity of the electrolyte.

The deposition process is recommended to be carried out at a pH of 7-9, a temperature of 25-70 s and a current density of 0.1-3 A / dm.

The electrolyte is prepared as a follower: After dissolving all components in the required volume of distilled water, all components are introduced in powder form.

By reducing the above molar ratios between metal ions and sodium citrate or sodium hydroxide, and the ratio between metal ions and sodium hydroxide increases in the electrolyte, metal hydroxides fall out. An increase in the molar ratio between metal ions and sodium citrate is impractical because of a significant decrease in the alloy deposition rate.

By introducing sodium citrate into the electrolyte (sodium citrate and sodium hydroxide, a film of insoluble compounds is formed on the surface of the electrolytic alloy, consisting of products of interaction between citrate and metal oxides.

influencing the microstructure of the electrolytic alloy. Coatings with a smaller structure are deposited from this electrolyte, thereby increasing their microhardness to 530560 kg / mm.

Microhardness is also influenced by temperature and current density (DC),

So, at temperatures of 25, 45 and (Dk 1 A / dm), the microhardness of the coatings is 530, 560 and 540 kg / mm, respectively, and at current densities of 0.1, 1.2, 2 and 3 A / d (t 50c) the microhardness is 530, 560, 540 and 530 kg / mm, respectively (data obtained in the electrolyte of Example 2 shown in the table).

The invention can be illustrated by several examples presented in the table.

Thus, the microhardness of the coatings is significantly increased, and the quality of the coatings in general is also improved. In addition, the scattering capacity of the electrolyte is significantly increased.

Sulfuric acid, 71 1.0 Kiel Nickel chloride Sulfuric acid, 06 0.52 Balt sodium citrate Sodium hydroxide 0.48 0.28 Boric acid 0.25 Sodium chloride Molar ratio Me Molar ratio: NaOH Temperature, ° C Current density , A / dm Current output,% 0.100 0.09 0.020 0.050 0.03 O, 100 0.015 1: 0.6 1: 0.09 55 0.8 97 97.3250.5 0.05.150 0.1250 , 4 O, 3501, 0 0.0800.3 1: 0.7 1: 1 1: 0.016 1: 0.3 55 55 1 98

Scattering ability,% 10

Coating thickness, micron 100

 10 12 13

6 b 420 34-0

Note: the scattering ability of the defined formula of the invention

Claims (3)

1. The electrolyte for the deposition of coatings from an alloy of nickel-cobalt containing nickel sulfate and nickel chloride, cobalt sulfate and sodium citrate, which also, in order to increase the microhardness of the coatings, contains sodium hydroxide the following ratio of components, mol / l: Nickel sulphate Nickel chloride Cobalt sulphate Sodium citrate Sodium hydroxide Table continuation 48 50 65,100 100 100 25 22 8 7 530 560 are poured into Herint's and Blum's cells and calculated using Field's formula, 2. The electrolyte according to claim 1, characterized in that the ratio of the total concentration of nickel and cobalt ions to the concentration of sodium citrate is 1.0: 0.6-1.0: 1.0. 3. The electrolyte according to claim 1, wherein the ratio of the total concentration of nickel and cobalt ions to the concentration of sodium hydroxide is 1.0: 0.09-1.0: 0.3. Sources of information taken into account in the examination i; Fedotiev N.P. et al. Electrolytic alloys. - M.-L.i Mashgiz, 1962, p. 228. 2. USSR author's certificate number 195277, cl. From 25 D 3/56, published .. 1967.