The precipitation of
silver sulfide ([Ag.sub.2]S) was evident as observed the formation of black films on the reactor walls.
Silver sulfide sulfate was formed at temperatures between 250-500oC and decomposes to form Ag2SO3 and Ag2S at temperatures between 500-600oC.
Pseudomonas stutzeri AG259, the silver-resistant bacterial strain, isolated from a silver mine, intracellularly accumulated silver NPs along with some
silver sulfide ranging in size from 35 to 46 nm [63].
Resistor terminal corrosion results in electrical opens as the corrosion product,
silver sulfide, builds and consumes the terminal metallurgy.
Another reference describes the formation of a 200 angstrom thick layer of
silver sulfide in 100 hours at a concentration of just 100 [micro]g/[m.sup.3] [72 ppb] (Anon E 2008).
Randy Schuller ("Creep Corrosion on Lead-Free Printed Circuit Boards in High Sulfur Environments," SMTAI, October 2007): This corrosion of the silver and copper surface is primarily copper sulfide (Cu2S) with a small amount of
silver sulfide (Ag2S).
Both copper sulfide and
silver sulfide can form black marks on the skin.
(15) These particles are composed predominantly either of
silver sulfide or silver selenide; over time, most of the
silver sulfide is replaced with silver selenide.
The result is a film of tarnish, a dark coating of
silver sulfide.