Black zinc is a chromate conversion process on steel so would remain conductive.
However anodizing and alodine or alochrom are two distinct processes on aluminium: Alodine/alochrom is a light chemical surface treatment of aluminium which leaves ithe surface conductive but less prone to oxidisation. It does not provide a very mechanically durable or decorative/cosmetic finish. Anodising is basically induced oxidization of an aluminum surface, something that over time would occur naturally to some degree. It creates a hard outer skin to the aluminium. During the process, what can be considered as pores are openend up and these can be dyed prior to the pores being sealed, this provides the colouring process. The anodised surface is insulative, however plain or un-dyed anodising will normally readily break down with a star washer to make a conductive contact. Coloured anodising is often much harder and is not suitable where reliable galvanic contact is required. Chris From: [email protected] [mailto:[email protected]] On Behalf Of Tarver, Peter Sent: 14 January 2008 21:30 To: [email protected] Subject: RE: Zinc passivation vs. Stainless Steel hardware selection > From: Curt McNamara > Sent: Thursday, January 10, 2008 2:33 PM > > In my experience almost all anodize is non- > conductive. The only conductive one that I recall is black zinc. I don't know if the process to which you refer is the form of anodizing I've come across called 'Alodine' (also black), but I've seen Alodine used in earthing paths with several mating interfaces with success. Regards, Peter L. Tarver, PE [email protected] CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message its contents, and any attachments hereto are not intended to represent an offer or acceptance to enter into a contract and are not otherwise intended to bind the sender, Sanmina-SCI Corporation (or any of its subsidiaries), or any other person or entity. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message (including any attachments) may contain confidential information intended for a specific individual and purpose. If you are not the intended recipient, delete this message. If you are not the intended recipient, disclosing, copying, distributing, or taking any action based on this message is strictly prohibited. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
