Ask the Expert Question-and-Answer Archive
(Hard Chrome Plating)
by Larry Zitko, ChromeTech, Inc.
Determining if an Object is Chrome Plated
Q. First, how do we determine whether or not object is chrome plated? Second,
is there a simple test to determine if plating is truly hard chrome?
A. Question 1:
If you are only dealing with chromium electrodeposits, and you merely wish
to detect the presence or absence of the chrome on carbon (not stainless)
steel, you can swab the cleaned region with a Blue Vitriol solution. It is
made by dissolving enough copper sulfate in water to make up a strong
solution (I don't think the exact concentration is critical), then adding a
small amount of sulfuric acid to make the solution acidic. Unplated regions
will turn a copper color, while chromium plated areas will retain the
silvery chromium appearance.
If you wish to identify whether the deposit is chromium, you can place it in
contact with warm, concentrated hydrochloric acid. Chromium will form a
greenish film as it is immersion stripped by this solution.