DE1004010B - Process for the production of firmly adhering and shiny galvanic metal coatings - Google Patents

Description

GERMAN

The subject of the patent 863 159 is a process for the production of firmly adhering and shiny galvanic Metal coatings using organic disulfimides or their water-soluble salts as additives to the metal salt baths. These additives result in firmly adhering and glossy coatings.

It has now been found in a further development of this process that organic disulfimides which contain halogen substituents have a significantly improved effect. This consists primarily in the fact that the hydrogen deposition that occurs during electroplating is suppressed to a minimum, as a result of which practically pore-free metal deposits are achieved. The suppression of the formation of pores allows, moreover, to work at higher values p _H, so that current densities can be applied to 8 Amp./dm ² and higher. This results in higher throughputs and the process becomes more economical.

Halogen-substituted organic disulfimides are dialkyl or diaryldisulfimides or mixed ones Arylalkyl disulfimides or their water-soluble salts understood as halogen substituents primarily chlorine and bromine. Particularly favorable effects are obtained with halodiaryldisulfimides, which are in the core may also contain alkyl substituents. The following are examples of these products: 4-bromo-dibenzene disulfimide, 4-chloro-dibenzene disulfimide, 4,4'-dibromo-dibenzenedisulfimide, 4,4'-dichlorodibenzenedisulfimide, 4-bromo-4'-chloro-dibenzene disulfimide, 3, 4, 3 ', 4'-tetrachloro-dibenzene disulfimide ^ -Methyl-bromo-dibenzene disulfimide, 4-ethyl-4'-bromo-dibenzenedisulfimide or another 4-alkyl-4'-bromo- or 4-alkyl-4'-chloro-dibenzenedisulfimide (Branched or unbranched alkyl radicals with a maximum of 8 carbon atoms), 3-chloro-4, 4'-dimethyldibenzene disulfimide, 3, 3'-dichloro-4, 4'-dimethyl-dibenzenedisulfimide, 4-chlorobenzene-methane-disulfimide, 4-chlorobenzene-ethane-disulfimide or another 4-halobenzene alkane disulfimide, where halogen is chlorine or bromine and the alkane radical is straight or branched chain can be and should contain a maximum of 8 carbon atoms. The disulfimides can be used as such or in the form of their water-soluble salts with inorganic or organic bases, e.g. B. the alkali or ammonium salts applied will.

The process is primarily intended to be used in the production of nickel deposits, but it is also for the production of other metal deposits, ζ. B. of cadmium precipitates, useful.

The brighteners used according to the invention can advantageously also be used in combination with leveling agents will. Suitable leveling agents are, for. B. Products, as they are obtained through implementation from tertiary or polynuclear aromatic-type heterocyclic nitrogen bases and sultones which Process for producing firmly adherent

and shiny galvanic

Metal coatings

Addendum to patent 863 159

Applicant:

DEHYDAG,

Deutsche Hydrierwerke GmbH,
Düsseldorf, Henkelstr. 67

Dr. Alfred Kirstahler, Düsseldorf,

and Dr. Wennemar Strauss, Düsseldorf-Holthausen,

have been named as inventors

have salty character. There are also compounds such as bis- or polythioureas, -isothioureas, -thiocarbaminates etc. or also conventional known levelers can be used. aside from that wetting agents, conductive salts or other brightening agents can also be used in the process. As an additional gloss agent are z. B. the non-halogen-substituted organic disulfimides are suitable.

The use concentrations for the agents according to the invention are between 0.1 and 10 g / l, preferably between 0.5 and 5 g / l bath liquid. It is used at higher temperatures, e.g. B. worked 50 to 60 ° C at _pH values between 1.5 and 6, preferably at 4.5 to 5.5 and at current densities of up to 8 Amp./dm ² and above.

example

1 g / l of sodium 4-bromo-4'-chlorodibenzene disulfimide are placed in a nickel salt bath of the Watts type, which contains 200 g of nickel sulfate, 60 g of nickel chloride and 40 g of boric acid per liter of bath liquid. Even in the absence of wetting agents, pore-free, high-gloss nickel coatings are obtained with current densities of up to 8 amps / dm ^2.

By adjusting the p _H -value of the bath liquid to 2 to 3, the current densities can be increased up to 10 Amp./dm. ² Instead of the disulfimide mentioned

609 838/335

It is also possible to use other halogen-substituted disulfimides according to the table below, in the the concentrations of the agents to be used for the optimal gloss effect are given.

Tabel

Brightener

Sodium 4-bromo-dibenzenedisulfimide

4,4'-Dibromo-dibenzenedisulfimide sodium 4,4'-Dichlorodibenzenedisulfimide sodium. 3, 4, 3 ', 4'-tetrachlorodibenzene disulfimide

sodium

4-chloro-dibenzoldisuh ^c imide sodium

g / l

5.0 3.0 2.0

1.0 0.5

IO

The leveling effect of the above gloss bath can, if necessary, be improved by 0.4 to 0.5 g / l quinolinium propane sulfonic acid or another leveling agent of this type is added. The additional amounts of levelers are between 0.1 and 1 g / l, preferably 0.3 to 0.6 g / l.

Claims (5)

PATENT CLAIM: 1. Further development of the process for producing firmly adhering and shiny galvanic metal coatings according to patent 863 159, characterized in that instead of the there used Organic disulfimides or their water-soluble salts used those organic disulfimides which Contain halogen substituents. 2. The method according to claim 1, characterized in that halogen-substituted diaryldisulfimides or their water-soluble salts are used. 3. The method according to claim 1 and 2, characterized in that one salt-like reaction products from tertiary mononuclear or polynuclear nitrogen bases of the aromatic type and sultones are also used. 4. The method according to claim 1 to 3, characterized in that non-halogen-substituted disulfimides used. 5. The method according to claim 1 to 4, characterized in that known wetting agents, conductive salts, Leveling agents and polishing agents also used. © «09 838/335 2.57