SILVER COATED COPPER FLAKES AND METHODS OF THEIR MANUFACTURE

摘要

Compositions having copper flakes coated with silver, where the silver is present as a hermetically closed metal shell around the copper, are described. The hermetically closed metal shell can limit oxidation of copper for at least 365 days at a temperature of less than 100 °C. The composition can also contain palladium in an amount of about 1 % or less by weight of silver in the shell. Palladium limits the migration of copper from the core flakes to the silver shell at temperatures below 250 °C. Methods of manufacturing copper flakes coated can include the steps of treating copper flakes with an acid to form acid treated copper flakes, treating the acid treated copper flakes with a polyamine to form polyamine treated copper flakes, depositing silver on the polyamine treated copper flakes to form copper flakes comprising silver deposits, and depositing silver onto the copper flakes comprising silver deposits.