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48 SMT007 MAGAZINE I JULY 2025 K N O C K I N G D OW N T H E B O N E P I L E Solderability Overview In 1983, the Department of Defense identified that over 40% of military electronic system failures in the field were electrical, with approximately 50% attributed to poor solder connections. Investiga- tions revealed that plated finishes, typically nickel or tin, were porous and non-intermetallic. This porosity allowed oxide penetration into the base metal, compromising solder joint integ- rity and leading to field failures. Consequently, the MIL-STD-883 solderability testing standard was established to ensure all components used in high- reliability applications would be reliably solderable. This shift in standards favored hot solder dip fin- ishes, which produce a fused, homogeneous tin- lead (SnPb) coating, enhancing solderability and joint reliability. Addressing End-of-life Component Solderability Issues, Part 4 by Nash B ell, BEST, Inc. Solderability testing evaluates how effectively molten solder wets the surface of electronic com- ponents, indicating how easily a strong and reli- able solder joint can be formed. It provides a crit- ical measure of the surface's ability to adhere and create a solid electrical and mechanical con- nection. This testing is primarily used to assess the solderability of device package terminations, such as leads, pads, and terminal surfaces, which can vary significantly depending on the solder alloy used. Different alloys, including lead-based and lead-free solders, can exhibit distinct wetting behaviors, making accurate testing essential for ensuring reliable assembly. Several industry-standard solderability test- ing methods are used to evaluate component sur- faces. The most common are MIL-STD-883 Method