Why passivate if part is plated?

A. Only reason that comes to my mind is to avoid stains or corrosion in the mean time they are plated. Passivation will have to be eliminated and parts be activated for plating to proceed.

A. I could be misunderstanding something, but I have to agree with you that it seems to make absolutely no sense. It's challenging enough to reliably activate stainless steel so that it can be successfully plated without deliberately passivating it first :-)

A. We also get similar requests, stainless for passivate and black oxide or passivate and electropolish. I suppose the engineer who decided on these processes for their parts wants to ensure against any free iron that may be present from the machining stages of production.

A. I get variations of this question all the time. Usually the question is about whether the passivation will affect adhesion of the plating. We have some customers who are passivating before plating "to get rid of any free iron on the surface". As stated above, this might be necessary if the parts are kept in inventory for a period of time in which the iron could rust prior to plating and begin a serious problem if left unattended. However, we see no reason other than this to passivate, since the activation process (made more difficult by the passivation) will take care of any surface problems prior to plating. When asked whether the passivation will affect adhesion we generally tell our customers that it will not help, but could adversely affect the adhesion of the plating. Bottom line- if you are plating immediately there should be no reason to passivate it first.