Passivate finish vs. Cadmium Plating?

A. Unfortunately, Alex, 'passivate' only means to render a surface less active. It's a very inexact term. But it can mean:

- the application of a chromate conversion coating to a cadmium plated surface (cadmium plating will quickly get white rust without it, and cadmium plated parts are virtually always chromium conversion coated, i.e., 'passivated' ...

- or it can mean to dip stainless steel (CRES) in nitric acid, or nitric acid plus chromic acid, or citric acid ⇦ on eBay or Amazon [affil links] to make it less prone to rusting.

Since you are talking about CRES, the latter seems more applicable, but it's only a guess until the exact context is understood. There should be a spec number you are expected to comply with, and that spec number should supply the necessary context. Good luck.