CS257414B1 - Lee-forming and leveling additive prg shiny working nickel plating bath - Google Patents

Abstract

A composition of additives for a galvanic nickel plating bath is formulated, which ensures high cure and leveling ability at a low concentration of components. The additive contains an acetylenic aliphatic alcohol and/or alcohol ether, substituted aminoacetylene, unsaturated aliphatic sulfonic acid and/or its alkali salt and naphtholsulfonic acid and/or its alkali salt in defined amounts and a solvent.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gloss-setting and leveling additive for a bright-working galvanic nickel-plating bath for the purpose of providing a shiny galvanizing bath. for the deposition of shiny nickel coatings.

Organic substances of various types are added to the electroplating baths containing nickel sulphate, nickel chloride and boric acid. In particular, o-toluenesulfimide and naphthalenesulionic acids are known as primary brighteners. In addition, secondary brighteners such as coumarin derivatives, or acetylenic alcohols, abrasions, and amines (e.g. U.S. Pat. Nos. 3,515,652, 3,550,548,

546,081, DOS 1,953,707, DAS 1,496,955).

A disadvantage of the prior art additives is that a high concentration in the bath is necessary to obtain a high gloss and leveling ability. The wood-forming additives and their degradation products are incorporated into the coating during electrolysis and increase the sulfur and carbon content thereof, resulting in a deterioration of the corrosion resistance of the coating, an increase in its hardness, brittleness and internal stress. The deposited coatings have unsatisfactory mechanical properties and are susceptible to cracking during use of the articles provided therewith.

The disadvantages of the known additives are largely eliminated by the brightening and leveling additive for the electroplating nickel plating according to the invention, which consists in that the additive contains from 2 to 15% by weight. an acetylenic aliphatic alcohol and / or a C 3 -C 8 alcohol ether in the aliphatic chain, for example 3- (2-hydroxyethoxy) -1-propyne, from 0.1 to 2% by weight of a substituted C 2 -C 4 acetylene chain %, for example dimethylaminopropin, from 2 to 15 wt. not of a saturated C 2 -C 8 aliphatic sulfo acid and / or an alkali salt thereof, for example etinsulfonic acid and / or sodium vinyl sulfonate, from 10 to 40% by weight of naphtholsulfonic acid, and / or an alkali salt thereof, for example 2-naphthol-6, 8 disulfonic acid and / or sodium 2-naphthol-4-sulfonate, and from 20 to 80% by weight of a solvent, for example a water-soluble alcohol or water.

The additive according to the invention is added to the nickel-plating bath in an amount of 0.2 - 2 g per 1 liter bath. At this overall low concentration of the additives, a high degree of gloss and leveling is achieved by suitable combination and synorgic effect. 8 - 15% and low internal stress. Their corrosion resistance is therefore higher than that of coatings avoided by the use of known brighteners because coatings are not susceptible to cracking due to satisfactory mechanical properties.

The invention is explained in more detail below by means of examples of a possible specific embodiment thereof.

Example 1

1,4-b is - (2-hydroxyxy) -2-butylamine dimethylaminopropin sodium vinyl sulfonate 2-naphthol-6,8 sodium sulfonate ethanol

This ingredient was added with a bath of the following composition:

NiS0 ₄ 7H ₂ 0 NiCl .6H _{of about} 0 H3BO3 saccharin in an amount by weight%.

0.5 wt.

% wt.

% wt.

64.5 wt.

g per 1 liter to nickel100

200

ga «a

Samples were plated in the bath to determine the properties of the deposited nickel coating. Their tests showed that the clad coating at 5 A / dm had an equalizing ability of 58 - 62% and the internal stress at 20 µm was 0 - 2 MPa.

Example 2

3- (2-hydroxyethoxy) -1-propyne 1,4-bis- (dimethylamino) -2-butyne etinsulfonic acid sodium 2-naphthol-4-sulfonate water% by weight * 0.1% by weight ·% by weight · 40% by weight · 47.9% by weight ·

This additive was added in an amount

0,5 g per 1 liter into nickel-plating bath

NiS0 ₄ .7H ₂ 0 300 gl ^-1 NiCl2.6H20 60 β.Γ ¹ h3bo ₃ 40 gr · ¹ o-toluenesulfimide 2 g ·! ** ^

The plated specimens from this bath were subjected to mechanical properties tests which yielded the following results: coating thickness ..... 20 yum internal stress · 15% elongation ....... 12% equalizing ability..55%

The coatings were deposited at a current density of 5 a / dm.

The invention can be used in both nickel-plating and hinged nickel plating, particularly where low internal stresses of the coating and high ductility are required, while at the same time high leveling ability.

Claims (1)

SUBJECT OF THE INVENTION A gloss-forming and leveling additive for a shiny galvanic nickel bath comprising 2 to 15 wt. an acetylenic aliphatic alcohol and / or a C 3 -C 8 alcohol ether in the aliphatic chain, for example 3- (2-hydroxyethoxy) -1-propyne *, from 0.1 to 2% by weight of a substituted C 2 -C 4 acetylene chain % of an unsaturated aliphatic sulfonic acid having 2 to 8 carbon atoms, and / or an alkali salt thereof, for example etinsulfonic acid and / or sodium sulfonate vinyls, from 10 to 40 wt. % of naphtholsulfonic acid and / or its alkali salts, e.g. 2-naphthol-6,8 disulfonic acid and / or sodium 2-naphthol-4-sulfonate, and from 20 to 80 wt. solvents such as water-soluble aliphatic alcohol or water ·