CS217566B1 - A method for the electrolytic deposition of a ternary nickel-iron-cobalt alloy - Google Patents

Abstract

The invention relates to a method of electrolytic deposition of nickel, iron and cobalt alloys from aqueous solutions containing complex sulfosalicylates of these metals. The essence of the method of electrolytic deposition of nickel-iron-cobalt alloy according to the invention lies in the fact that electrolysis is carried out by a cathodic current consisting of a series of consecutive rectangular current pulses. The amplitude of the pulses can exceed the effective value of the Faraday current by up to twelve times. The pulse duration is selected in the range of 5.10~6 to 2.10-1 seconds.

Description

The present invention relates to a process for the electrolytic deposition of nickel, iron and cobalt alloys from aqueous solutions containing complex sulfosalicylanes of these metals.

The principle of the electrodeposition of the nickel-iron-cobalt alloy according to the invention is that the electrolysis is carried out by a cathodic current consisting of a series of successive rectangular current pulses. The amplitude of the pulses can be up to 12 times the effective value of the Faraday current. The pulse duration is selected from 5.10 ~ ⁶ to 2.10 ^-1 seconds.

The present invention relates to a process for the electrolytic deposition of nickel, iron and cobalt alloys from aqueous solutions containing complex sulfosalicylanes of these metals.

Recently, there has been considerable interest in galvanic engineering with cobalt alloys, including the above-mentioned alloy. The reason is its advantageous magnetic and mechanical properties such as very low coefficient of thermal expansion, hardness, toughness and the like.

The previously disclosed methods for the deposition of Ni-Fe-Co-type alloys are based on electrolytes containing simple salts, especially sulphates, with the addition of halides and complexing agents, using a conventional method of conducting electrolysis, i.e. constant current electrolysis. In particular, the high internal stress is an obstacle to the wider applicability of the alloys thus produced. This drawback has recently been partially eliminated by deposition from a complex based on complex sulfosalicylamines of nickel, iron and cobalt, so that Ni-Fe-Co-type alloys can be deposited even in thick layers for some less demanding applications in galvanoplasty.

The principle of the electrolytic deposition of the nickel-iron-cobalt alloy according to the invention consists in that the electrolysis is carried out by a cathodic current consisting of a series of consecutive rectangular current pulses. The amplitude of the pulses can be up to 12 times the effective value of the Faraday current. The pulse duration is selected in the range of 5.10 " ⁶ to 2.10" ¹ second.

Said method of depositing Ni-Fe-Co layers results in a reduction in the content of undesirable impurities on the layer, in particular adsorbed basic compounds. The practical consequence of this is, in particular, a reduction in macropraction, as well as an improvement in the appearance and mechanical properties of the layers thus deposited compared to those deposited by a constant current. The low level of internal stresses in thick layers of Nl-Fe-Co eliminated by current pulses allows their use even for shape-intensive galvanoplastic shells.

This method of electrolytic deposition of Ni-Fe-Co-type alloys is illustrated by the following examples, which are not intended to be limiting or limited thereto.

The length of intervals in time units between individual pulses T _o is given by the formula:

T _o = T _p (i _{p -} i _e ) / i _e see Fig. 1 where Tp. . . . pulse duration ip. . . . pulse amplitude ie. ,. . value of Faradayic current

He did

Electrolyte composition (aqueous solution):

0,01.10 ³ mol / m ³ cobalt sulphosalicylate 0,24,10 ³ molm ³ iron sulphosalicylate 0,56.10 ³ mol / m ³ nickel sulphosalicylate

0.08.10 ³ mol / m ³ potassium iodide pH = 4

Electrolyte temperature: 50 ° C

Current parameters:

Effective value of cathode current density:

i _e = 3 A.dnr ' ²

Pulse amplitude:

i _p = 15 A.dm- ²

Pulse duration:

Tp = 1.10-3 sec

Excluded layer composition:

48.1% Ni, 48.3% Fe, 3.6% Co

Makropnutí:

136 MPa (dilatometric) Example 2

For the composition and temperature of the electrolyte, see Example 1. Current parameters:

Effective value of cathode current density:

i _e = 3 A.dm ^-2

Pulse amplitude:

i _p = 36 A.dm- ²

Pulse duration:

T _p 5.10-es

Pulse interval length:

T _o = 55.10-6

Excluded layer composition:

47.5% Ni, 50.3% Fe, 2.2% Co

Macroping layer:

152 MPa

Example 3

Electrolyte composition (aqueous solution):

0.02.10 ³ mol / m ³ cobalt sulfosalicylate 0.10.10 ³ mol / m ³ iron sulfosalicylate 0.70.10 ³ mol / m ³ nickel sulfosalicylan 0.05.10 ³ mol / m ³ potassium bromide 0.5 kg / m ³ Neokal pH = 5.1

Electrolyte temperature: 60 ° C

Current parameters:

Effective value of cathode current density:

e _e - 5 A.dm ^-2

Pulse amplitude:

- 15 A.dm ^-2

217568

Pulse duration:

Tp = 10.1 ^"5 s

Pulse interval length:

T _o = 2.IO- ⁵ sec

Excluded layer composition:

50.8% Ni, 40.7% Fe, 8.5% Co

Macroping layer:

102 MPa

Example 4

Electrolyte composition (aqueous solution):

0,03.10 ³ mol / m ³ cobalt sulphosalicylate 0,08.10 ³ mol / m ³ iron sulphosalicylate 0,70.10 ³ mol / m ³ nickel sulphosalicylate 0,08.10 ³ mol / m ³ potassium bromide 2,0 kg / m ³ saccharin

0.2 kg / m ³ sodium lauryl sulphate pH 4.6

Claims (1)

SUBJECT Method of electrolytic deposition of a ternary nickel-iron-cobalt alloy from a water bath, the basic component of which is the complex sulfosalicylany of nickel, iron and cobalt, characterized in that the electrolysis is carried out by cathodic Electrolyte temperature; Deň: 32 ° C Current parameters: Effective value of cathode current density: i _e = 5 A.dnr ² Pulse amplitude: i _p = 40 A.dm- ² Pulse duration: T _p = 1.10-2 sec Pulse interval length: T _o = 7.10-2 _s Excluded layer composition: 52.1% Ni, 35.1% Fe, 12.7% Co Macroping layer: 89 MPa Invention, the stream, consisting of a rectangular current pulse having an amplitude exceeding the effective value of the current as much as twelve Faradayického and the pulse duration is in the range of 5.10 ⁶ to 2.10 ^"1. 1 sheet of drawings 21 7 5 6