SU1300040A1 - Aqueous composition for correcting the ph value of acidic solutions for chemical nickel-plating - Google Patents

Abstract

The invention relates to chemical nickel plating, in particular, compositions for adjusting the pH of acidic solutions of chemical nickel plating, and can be used in instrument engineering. The purpose of the invention is to improve the performance and stability of acidic solutions of chemical nickel plating. Their pH is adjusted with a solution containing 15-20 g of sodium hydroxide, 30-80 g of sodium trisodium phosphate and water to 1 l. The introduction of sodium trisodium phosphate into the solution to adjust the pH based on sodium hydroxide improved the performance and stability of the chemical nickel plating solution; in particular, the solution withstand 22-35 corrections instead of 3-5. 1 tab. с 9 (L Сл5, О О О О 4

Description

The invention relates to chemical deposition of metallic coatings from solutions, in particular, compositions for adjusting the pH of chemical nickel plating solutions, and can be used in instrument engineering for creating structural elements with nickel coatings for various purposes.

The purpose of the invention is to increase the working capacity and stability of chemical nickel plating solutions.

A test of the proposed pH adjustment composition was performed for a 15 solution of chemical nickel plating containing, g / l:

Sulfur nickel 20 Sodium hypophosphite. 25 Sodium acetate 10 20 Malic acid 20 Thiourea .0.003

at pH 4.5, loading density 1 dm / l, temperature 90 ° С. During the initial preparation of the solution, the pH was adjusted to the specified value by the proposed correction composition.

The calculated hot nickel-plating solution with a pH of 3.9 was injected with calculated amounts of the salt of nickel and hypophosphite, and then, with continuous stirring, the lime and the proposed corrective compositions are given in table.35

From the presented data, it follows that the proposed composition has not less than 6 times higher performance, allows you to bring

25

thirty

It enhances the stability of chemical nickel plating solutions: when adjusting the pH with sodium hydroxide, nickel hydroxide precipitates at the sites of its introduction into the solution, which are centers of the bulk decomposition of the solution, while introducing the proposed pH adjustment composition into the nickel plating solution did not result in its decomposition. The solution is stable for all corrections. The introduction of chemical nickel into the solution with a correcting composition of trisodium phosphate improved the quality of nickel coatings, since the indicated component, by improving the wettability of the coating part with the solution, prevents the formation of a hydrogen pitting on the coating.

With a decrease in the content of trisodium phosphate in the composition of the correction below 30 g / l contributes to the bulk decomposition of the solution of chemical nickel plating after 15-20 corrections. An increase in its content of more than 80 g / l is difficult due to limited solubility in sodium hydroxide. A change in the concentration of sodium hydroxide in the range of 15–20 g / l. Does not significantly affect the results achieved.

Claims (1)

Invention Formula An aqueous composition for adjusting the pH of acidic solutions of chemical nickel plating containing sodium hydroxide is sufficient for pH to a working value of a lower volume that, in order to increase the working capacity of the corrector, reducing the dilution of the chemical nickel plating solution, does not contain com plex forming agents (ethylene diagline, ammonium hydroxide) 5 that significantly reduce the precipitation rate. In addition, the proposed composition compared with the known cost It enhances the stability of chemical nickel plating solutions: when adjusting the pH with sodium hydroxide, nickel hydroxide precipitates at the sites of its introduction into the solution, which are centers of the bulk decomposition of the solution, while introducing the proposed pH adjustment composition into the nickel plating solution did not result in its decomposition. The solution is stable for all corrections. The introduction of chemical nickel into the solution with a correcting composition of trisodium phosphate improved the quality of nickel coatings, since the indicated component, by improving the wettability of the coating part with the solution, prevents the formation of a hydrogen pitting on the coating. With a decrease in the content of trisodium phosphate in the composition of the correction below 30 g / l contributes to the bulk decomposition of the solution of chemical nickel plating after 15-20 corrections. An increase in its content of more than 80 g / l is difficult due to limited solubility in sodium hydroxide. A change in the concentration of sodium hydroxide in the range of 15–20 g / l. Does not significantly affect the results achieved. Invention Formula An aqueous composition for adjusting the pH of acidic solutions of chemical nickel plating containing sodium hydroxide is sufficient for the stability and stability of the solutions, it additionally contains trisodium-phosphate tphi the following ratio of components, g / l: 45 Hydroxide ne.trk 5 15-20 Trinatriyfosfat, g 30-80 Water, lDo 1 Sodium hydroxide Trisodium Phosphate Deposition rate nickel, micron / h The number of corrections before the start of the decomposition of the solution Volume adjusting composition, ml / l solution Editor E. Kopcha Order 1120/26 Circulation 937Subscription VNIIGSh of the USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and Printing Plant, Uzhgorod, st. Project, 4 202020 503080 12-1612-1611-16 30-3522-2530-35 120 130 100 Compiled by R. Ukhlinova Tehred I.Popovich Proofreader L. Patay