Hi Kathy, My knowledge of passivation is somewhat limited. I have only seen it used for stainless steel (steel with typically high nickel content). I also found a little on how/why it is done: With austenitic stainless steel, such as the 300 series, once a corrosion site has started it only gets worse, being continuous and self-catalyzing. In corrosive environments the growth of the corrosion site will accelerate rapidly! Thus, proper cleaning and passivation of surfaces prior to use is essential to achieve maximum resistance to corrosion. Most companies have used and continue to use methods for cleaning and "passivating" stainless steel which utilize mineral acids such as nitric acid and phosphoric acid. Their effect is limited to surface iron, although in many cases this method redeposits contaminant iron on the surface again. Nitric acid is known to many times produce pitting corrosion. There are many problems with long term use of mineral acid applications, especially under corrosive environments. Although not really "new", an emerging technology that is proving to be a vast improvement over the mineral acids is the use of safer organic acids such as citric acid. These are very effective materials which complex and remove a variety of metallic ions that would otherwise adversely affect the corrosion resistance of the stainless steel. These acids are materials that work in aqueous solutions to tie up metal ions so that they are no longer effective or able to have a negative impact. After stripping the metal ions from the surface, the citric acid forms a water soluble complex with a metal ion. It will not precipitate the metal ions again like the mineral acids are known to do. I cannot vouch for the correctness of the claims in this information nor comparing one method versus another. In your application I wonder why you would do this to a "pure" nickel deposit and what it would do to all the other metals that may be nearby. Have fun, Ahne. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Kathy Kuhlow Sent: Thursday, February 07, 2002 06:50 To: [log in to unmask] Subject: [TN] Nickel Passivation << File: TEXT.htm >> What has actually happened to the nickel on a pad when it is passivated? Can this nickel also be unpassivated? TIA Kathy --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------