Agree with Dave. Matte tin should look dull silver-gray. SnO2 is white. I have seen matte tin get quite white if the parts have been stored a "long" time allowing the units to get oxidized. Best regards, Leo Leo M. Higgins III, Ph.D. Vice President, Technical Support Operations ASAT, Inc. 3755 Capital of Texas Highway, Suite 100 Austin, Texas 78704 office phone 512-383-4593 mobile 512-423-2002 [log in to unmask] www.asat.com The information contained in this electronic message is CUSTOMER/SUPPLIER PRIVILEGED AND CONFIDENTIAL INFORMATION intended only for the use of the individual or entity named above. If the reader of this message is not the intended recipient, you are hereby notified that any dissemination, distribution and copying of this communication is strictly prohibited. If you have received this communication in error, please immediately notify the sender by electronic mail. Thank you. -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of David D. Hillman Sent: Thursday, January 19, 2006 4:30 PM To: [log in to unmask] Subject: Re: [TN] Soldering matte tin over nickel plating Hi John! A white deposit on a matte tin finish can not be a good thing and is not normal for the matte tin finishes I am familiar with. I would subject the components to the JSTD-002B Test S (Surface Mount Simulation test) to see if it passes. If it fails then you have leverage with your vendor based on data and not observation. Good Luck. Dave Hillman Rockwell Collins [log in to unmask] John Burris <johnhburris@GMAI L.COM> To Sent by: TechNet [log in to unmask] <[log in to unmask]> cc Subject 01/19/2006 08:54 [TN] Soldering matte tin over AM nickel plating Please respond to TechNet E-Mail Forum <[log in to unmask]> ; Please respond to John Burris <johnhburris@GMAI L.COM> Dear TechNetters, We are just starting our journey into lead-free (we are currently covered under Article 9, but we can see the handwriting on the wall), and we are starting to deal with some issues as suppliers are making component changes to comply with RoHS. The component at issue is a heat sink for a TO-220 transistor. Flux is 2% no-clean. Solderability is not good; partial solder adhesion (about 20-30%) on the mounting tabs. 90% coverage is required by standards. The matte tin finish appears to have a white deposit that can be removed by either scraping or cleaning with a mild solvent. Vendor says this is normal and should not affect solderability. Thoughts? John Burris Automated Logic 1150 Roberts Blvd. Kennesaw, GA 30144-3618 01.770.795.4827 (Office) 01.770.795.3527 (Facimile) 01.404.431.9109 (Cellular) -- No virus found in this outgoing message. Checked by AVG Free Edition. 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