Publications

Results 126–150 of 171
Skip to search filters

The effects of long-term storage on the solderability of immersion silver coatings

Proceedings of the 3rd International Brazing and Soldering Conference

Lopez, Edwin P.; Vianco, Paul T.; Lucero, Samuel J.; Buttry, R.W.; Rejent, Jerome A.; Martin, Joseph

The solderability of an immersion Ag finish was evaluated after the exposure of test specimens to a Battelle Class II environment, which accelerates the storage conditions of light industrial surroundings. The solderability metric was the contact angle, (θC), as determined by the meniscometer/wetting balance technique. Auger surface and depth profile analyses were utilized to identify changes in the coating chemistry. The solderability test results indicate that there was no appreciable loss in solderability when the immersion Ag coated coupons were packaged in vapor phase corrosion (VPC) inhibitor bags and/or inhibitor bags with VPC inhibitor paper and aged for 8 hours, 1 week or 2 weeks in the Battelle Class II environment. An increase in surface carbon concentration after aging did not appear to significantly affect solderability. Copyright © 2006 ASM International®.

More Details
TYPE Conference YEAR 2006
ScopusOSTI

An evaluation of the spring finger solder joints on SA1358-10 and SA2052-4 connector assemblies (MC3617,W87)

Vianco, Paul T.; Kilgo, Alice C.; Zender, Gary L.; Hlava, Paul F.

The SA1358-10 and SA2052-4 circular JT Type plug connectors are used on a number of nuclear weapons and Joint Test Assembly (JTA) systems. Prototype units were evaluated for the following specific defects associated with the 95Sn-5Sb (Sn-Sb, wt.%) solder joint used to attach the beryllium-copper (BeCu) spring fingers to the aluminum (Al) connector shell: (1) extended cracking within the fillet; (2) remelting of the solder joint during the follow-on, soldering step that attached the EMR adapter ring to the connector shell (and/or soldering the EMR shell to the adapter ring) that used the lower melting temperature 63Sn-37Pb (Sn-Pb) alloy; and (3) spalling of the Cd (Cr) layer overplating layer from the fillet surface. Several pedigrees of connectors were evaluated, which represented older fielded units as well as those assemblies that were recently constructed at Kansas City Plant. The solder joints were evaluated that were in place on connectors made with the current soldering process as well as an alternative induction soldering process for attaching the EMR adapter ring to the shell. Very similar observations were made, which crossed the different pedigrees of parts and processes. The extent of cracking in the top side fillets varied between the different connector samples and likely the EMR adapter ring to the shell. Very similar observations were made, which crossed the different pedigrees of parts and processes. The extent of cracking in the top side fillets varied between the different connector samples and likely reflected the different extents to which the connector was mated to its counterpart assembly. In all cases, the spring finger solder joints on the SA1358-10 connectors were remelted as a result of the subsequent EMR adapter ring attachment process. Spalling of the Cd (Cr) overplating layer was also observed for these connectors, which was a consequence of the remelting activity. On the other hand, the SA2052-4 connector did not exhibit evidence of remelting of the spring finger solder joint. The Cd (Cr) layer did not show signs of spalling. These results suggested that, due to the size of the SA1358-10 connector, any of the former or current soldering processes used to attach the EMR adapter ring and/or EMR shell to the connector shell, requires a level of heat energy that will always result in the remelting of the spring finger solder joint attached with either the Sn-Ag or the Sn-Sb alloy. Lastly, it was construed that the induction soldering process, which is used to attach the EMR adapter ring onto the shell, was more likely to have caused the remelting event rather than the more localized heat source of the hand soldering iron used to attach the EMR shell to the adapter ring.

More Details
TYPE SAND Report YEAR 2006
OSTIDOI
Results 126–150 of 171
Results 126–150 of 171