Pb-Free Electronics: Alternate Metal (Sn-Whiskers) & Alloy Problems

Lead has been used extensively in solders and finishes on PC Boards for years. The ever increasing disposal of outdated electronic equipment has caused world governments to mandate reduction or elimination of its use in electronics manufacture. Consequently, alternate high-performance materials are quickly being developed. Sn, the most widely used replacement metal, can grow "whiskers", or filamentary corrosion, which eventually shorts out the electronics. Not only is this a commercial problem, Sn "whiskers" in medical devices, satellites, missiles and other military or security-sensitive equipment can cause catastrophic problems. Other pure metal and alloy substitutes, such as Ag, Cu, Zn, Bi, In, Sb, and Cd, are also potential causes of failure for electronic equipment. These substitute materials must be developed, tested and monitored as quickly as possible to meet these new demands.