Man those are some nice pictures, Pat. I would LOVE to be able to look at them with SEM/EDX or maybe even better X-ray diffraction. In decreasing order of likelihood my guesses would be: CuS or Cu2S Ag2S And WAY down the list: Environmental contamination lead whiskers (not likely, really looks like dendrites) Tin pest (Just KIDDING!) Bev -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Wenger, George M. Sent: Thursday, March 08, 2012 7:29 PM To: [log in to unmask] Subject: Re: [TN] Black substance Dave, I was thinking the same thing. If you look at Chen's creep corrosion paper at APEX last year and the year before he should showed similar corrosion and while he originally thought it was due to the ImAg as he continued his evaluations he realized it happens also on OSP boards. Regards, George George M. Wenger Senior Principal Reliability / FMA Engineer Andrew Corporation - Wireless Network Solutions 40 Technology Drive, Warren, NJ 07059 (908) 546-4531 Office (732) 309-8964 Mobile E-mail: [log in to unmask] -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman Sent: Thursday, March 08, 2012 6:29 PM To: [log in to unmask] Subject: Re: [TN] Black substance Hi Pat - if the soldering process consumed all of the silver but you had pad edges that were exposed copper, you could have copper sulfide instead of silver sulfide as a possible corrosion product. The crystal structures looked very neat! Dave "Goodyear, Patrick" <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 03/08/2012 05:08 PM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to "Goodyear, Patrick" <[log in to unmask]> To <[log in to unmask]> cc Subject Re: [TN] Black substance The card has been stored in an enviromental room in the chassis, with controlled humidity, very near the Pacific Ocean. The FUZZ is on the edges of quite a few traces, as well as almost all of the land edges. I just finshed going over the board with a microscope at 45X to see if I could make any sense of it, where I removed the fuzz the copper edges of he traces show copper. When I cleaned the turret it looks like a tarnished silver spoon. Suspect some form of silver dendrite. Sorry no tires, I'm missing the winged shoe on my name. We sit on a bluff 90 feet above the Pacific, no one else within 5 miles as the seagull flies. Thanks for the ideas. Dave, the plating is most likely silver. The solder is 40-60 I would guess due to the age of it, these board were built around 1970 give or take as they are OEM when the power plant was built. Not sure exactly when 63-37 came around but I didn't run into it until around 75 when we put together the Pace repair course for the Navy Nukes in Idaho. pat -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Woolley, Mark D. (Mark) Sent: Thursday, March 08, 2012 2:49 PM To: [log in to unmask] Subject: Re: [TN] Black substance My first thought was silver sulfide. Were the PWBs stored in a high sulfur gas area? Nearby a tire factory, oil well or refinery, ot coal fired power plant? mark mark Mark Woolley |PTRL Laboratory | Avaya | 1300 West 120th Ave | Westminster, CO 80234 USA | -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory Sent: Thursday, March 08, 2012 3:33 PM To: [log in to unmask] Subject: Re: [TN] Black substance Hi Pat, Got your pictures and have them posted. Sorry for the delay, but I'm still running in low gear. Here they are, and all I can say is YIKES! http://stevezeva.homestead.com/whisker1.JPG http://stevezeva.homestead.com/whisker2.JPG http://stevezeva.homestead.com/whisker3.JPG http://stevezeva.homestead.com/whisker4.JPG http://stevezeva.homestead.com/whisker5.JPG These look like the classic silver/copper corrosion from being exposed to reduced sulfur gasses such as hydrogen sulfide. Here's a good paper that details it all: http://chavant.net/new_site/files/pdf/HP_ImAg_Corrosion_Paper_ISTFA_2006 1.pdf I would be very scared, very, very scared... Steve -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory Sent: Thursday, March 08, 2012 11:25 AM To: [log in to unmask] Subject: Re: [TN] Black substance Hi Pat, Reply to me with the pictures and I'll get them posted... Steve -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Goodyear, Patrick Sent: Thursday, March 08, 2012 1:39 PM To: [log in to unmask] Subject: [TN] Black substance Ok got a new one. Found on the plated portion of a turret a black fuzz, also on the riveted backside and the plated portions of all of the lands outside the soldered areas. It cleans right off with alcohol leaves no residue, is crystalline in structure and grows away from the metal has a coral like appearance. I have attached pictures but Steve is off today so don't know who else can post. Again a 40 year old board. Any ideas???? Pat . ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. 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