Degussa Aktiengesellschaft

Franz Simon

Manfred Schmidt

Wolfgang Zilske

Bernd Dorbath

Werner Huth

For the production of low carat rose to gold colored gold alloy coatings there are needed electrolytic baths containing soluble gold cyanide, soluble copper cyanide, potassium carbonate or potassium bicarbonate which produce corrosion resistant coatings of 13-18 carats and no physiologically hazardous cadmium. The baths of the present invention contain, in place of cadmium, 7.5 to 40 grams/liter of zinc as complex zinc cyanide.

Alkaline bath for the electrolytic deposition of low carat yellow

For the electrolytic deposition of gold alloys there is required a process with which low carat coatings can be deposited which nevertheless have a high resistance to tarnish. Such coatings are obtained from electrolytes which consist of a salt melt and contain gold salts, alkali thiocyanate and salts of one or more alloyings elements as constituents. Preferably the electrolyte contains per liter of salt melt 0.5 to 20 grams of gold, up to 300 grams of Cu, Zn, Sn, Cd, Ni, Ag, Pd, Ru and/or Pt, up to 200 grams of alkali cyanide and/or water.

Process for the electrolytic deposition of gold and gold alloy coatings

There are needed galvanic baths for the deposition of silver and silver alloys which exhibit a high resistance to sulfur and contain the least possible amounts of alloyed platinum group metals and/or gold. This is attained by using a salt melt as the electrolyte which melt contains a silver salt, alkali thiocyanate and salts of at least one alloying metal. Preferably the electrolyte contains per liter of salt melt 0.1 to 40 grams of silver and 1 to 200 grams of platinum metal and/or gold.

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Schmitten, Germany

Franz Simon