Blackened Silver Production

The mechanical method of blackening of silver jewelry involves applying black patterns to silver manually using a special gruel of graphite with iron oxide and a small amount of turpentine, which is dried, and the remains are removed using a suede cloth previously soaked in alcohol. The chemical or electrochemical methods of blackening of silver jewelry result in oxidized silver, as a result of which the metal is covered with a coating (film), and the jewelry itself changes color. The chemical method of blackening of silver takes place in several stages: degreasing silver; preparing an aqueous solution of liver of sulfur (sulfur and potassium carbonate or soda ash), heated to 80-90°C, applying it to the desired parts of the product and thoroughly washing the product under running water, gradually lowering its temperature, to fix the color, a well-dried product is polished. During the electrochemical blackening method, electrolysis of another type of solution is used, at a lower temperature (about 20°C), which includes sulfuric acid, sodium sulfide and acetone, requiring much less time. After such treatment, the product is thoroughly washed in running water, dried, and then polished. This method is more preferable, since after such treatment, the product has a long-term change in the color of silver, and the polished edges shine brighter, and the decoration retains its original appearance for a long time. The article presents a new electrochemical method for stable and uniform blackening of silver jewelry, which uses a previously developed theoretical mechanism for the formation of electrolytic oxygen bubbles during water electrolysis for intensive uniform formation of microdispersed oxygen bubbles over the entire area of the anode from silver jewelry (oxidation) in a specially designed electrolyzer.