Expanding on Rainer's points look here: http://www.corrosion-doctors.org/MatSelect/corrsilver.htm Dave Fish ----- Original Message ----- From: "Blomberg, Rainer (FL51)" <[log in to unmask]> To: <[log in to unmask]> Sent: Monday, December 03, 2001 6:27 AM Subject: Re: [TN] Red plaque on Silver plated wire? > I have never seen it, but have heard about it during investigation of 'Green > Plague'. The electronics industry term is "Red Plague" not Plaque, and is > corrosion associated with the use of silver-plated copper wire. Red Plague, > named for it's color, (as opposed to Green Plague) is the cuprous oxide > (possibly with some black cupric oxide)corrosion product that forms when a > galvanic cell is formed between copper and silver. This was first studied > in the sixties when it was established that 'red plague' originates at > breaks in the silver plating of copper wire strands in the presence of > moisture and oxygen. Although 'red plague' corrosion of silver plated wire > in service is extremely rare, for high-rel space applications, it is > necessary to control all steps in the handling and processing of the wire. > Control seems to be mainly by the wire manufacturer to provide a quality, > uniform plated thickness (at least 2 um and preferably 4 um) of silver > without imperfections such as scrapes or porosity. It is important that > manufacturers ensure they do not damage the continuity of the silver > plating. In addition, humidity controls can be implemented (dry-nitrogen > backfill or desiccant) for dry packaging to keep wire reels or spools below > 50% RH. > > More information is available and can be found in this book: > Metallurgical Assessment of Spacecraft Parts, Materials and Processes > (Second Edition) > Barrie D. Dunn > Praxis Publishing Ltd. > (See http://www.praxis-publishing.co.uk/space/metal.htm) > > > Rainer G. Blomberg > > Honeywell -Space Systems Clearwater > Staff Production Engineer > > 13350 US Hwy 19 N MS 802-3 > > Clearwater, FL 33764-7290 > (727) 539-5534 Phone > (727) 790-8738 Pager > (727) 539-4469 Fax > e-mail: [log in to unmask] > > > > -----Original Message----- > From: Kasprzak, Bill (sys) USX [mailto:[log in to unmask]] > Sent: Friday, November 30, 2001 3:08 PM > To: [log in to unmask] > Subject: [TN] Red plaque on Silver plated wire? > > > Anybody out there ever hear about having to control red plaque on silver > plated wire? > > This showed up on a spec for a job we're contemplating. > > Any and all ('cept wisecracks) responses appreciated. Thanks. > > Bill Kasprzak > Moog Inc., Electronic Assembly Engineering > > -------------------------------------------------------------------------- -- > ----- > 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 the following message: SET > Technet NOMAIL > 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 > -------------------------------------------------------------------------- -- > ----- > > -------------------------------------------------------------------------- ------- > 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 the following message: SET Technet NOMAIL > 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 > -------------------------------------------------------------------------- ------- > --------------------------------------------------------------------------------- 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 the following message: SET Technet NOMAIL 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 ---------------------------------------------------------------------------------