- Program Areas
- Energy and Water
- Environmental Restoration
- Munitions Response
- Resource Conservation and Resiliency
- Weapons Systems and Platforms
For more than 50 years, the electronics industry has relied on tin-lead (SnPb) solder as the primary means of interconnection between electronic devices. The European Union’s (EU) Restriction of Hazardous Substances (RoHS) directive and other international and domestic mandates to eliminate materials deemed hazardous to health have recently forced the electronics industry to adopt solders and termination finishes free of lead. While aerospace and defense electronics are excluded from these Pb-free mandates, many of their component suppliers are consumer electronics companies driven by the needs of volume customers who demand RoHS compliance in order to enter or preserve European markets. Suppliers sometimes provide existing products in two forms, but usually only temporarily before converting to a single Pb-free version. New products are being introduced almost exclusively in Pb-free form.
Avionics, defense electronics, and other high reliability electronic applications differ in significant ways from the vast majority of commercial and consumer electronic applications. Field environments often include extreme temperature and humidity, high altitude, and high levels of shock and vibration. Product lifetimes are often measured in decades, rather than in years.
The reliability of SnPb interconnections is well known and meets the requirements of these demanding applications. Based on the scientific information available today, there are reliability risks in using Pb-free solder and finishes in high performance electronics. These include the spontaneous formation of tin whiskers from Sn-based finishes that can create short circuits, reduce solder joint integrity, and reduce reliability by cross-contamination between the different alloys.
SERDP and ESTCP investments are aimed at:
- Developing a quantitative and mechanistic understanding of the role of Pb in inhibiting whisker growth
- Developing means for mitigating the risks associated with tin whiskers.
- Identifying and quantifying the reliability of Pb-free alloys