Why do some rhodium plated jewelry items seem to tarnish despite being plated?
With the exception of nickel and silver, any object plated with less than .10 microns of rhodium will eventually discolor due to the corrosive oxides that are “rising” through the microscopic pores within the rhodium’s surface. This type of surface tarnish will eventually appear “yellowish’ bright to the observer and is commonly found on decorative items such as jewelry chains and bracelets. Constant contact with skin oils and chemicals help accelerate surface discoloring. Most objects properly plated(assuming “active”porosity is eliminated) with .10 to .25 microns in thickness, will remain bright well into the future.
