Method for protecting silver and silver alloy surfaces against tarnishing

摘要

A method for protecting silver and silver alloy surfaces against tarnishing, characterized by initially subjecting the surface to be treated to cleaning pre-treatment in organic solvents; immersing the cleaned surface in an acid solution able to ensure formation of a thin layer of silver oxide; immersing the oxidized surface in a solution of at least one thiol of formula CH3(CH2)nSH where n is between 10 and 16; and chemically reacting the molecules of said thiol with the previously oxidized silver surface, in an environment containing water vapor at a temperature of at least 50° C.

主权项

1. A method for protecting silver and silver alloy surfaces against tarnishing, comprising:
initially subjecting a surface to be treated to cleaning pre-treatment in organic solvents; immersing the cleaned surface in an acid solution able to ensure formation of a thin layer of silver oxide; immersing the oxidized surface in a liquid solution of at least one thiol of formula
CH3(CH2)nSHwhere n is between 10 and 16, to provide a treated surface; and
thereafter, removing the treated surface from the liquid solution, subsequently drying the treated surface, and subsequently subjecting the dried surface to a separate heating treatment by placing said previously oxidized silver surface in an environment containing air at a temperature of at least 50° C. for at least ten minutes, thereby chemically reacting molecules of said thiol with the previously oxidized silver surface.