JayBrusseRevision2 继电器参考资料.pdf

The Continuing Dangers of Tin Whiskers and Attempts to Control Them with Conformal Coating Jong S. Kadesch Orbital Sciences Corporation/NASA Jong.S.Kadesch.1@ 301-286-2785 Jay Brusse QSS Group, Inc./NASA Jay.A.Brusse.1@ 301-286-2019 Figure 1. SEM photo of a tin whisker breaking out from beneath conformal coating (x625) Abstract: A 1998 commercial satellite failure caused by tin whisker induced shorts prompted NASA Goddard Space Flight Center (GSFC) to issue a NASA Advisory (NA-044 and NA-044A) (1,2) to remind the NASA community of the tin whisker phenomenon and the inherent risks associated with the use of pure tin plated components. Indeed the NASA Advisory served as a “reminder” since the spontaneous growth of tin whiskers from some tin plated surfaces has been known and studied for over 50 years with dozens of technical publications and several GIDEP Alerts produced during that time. During the 1990s the US Military modified most (but not all) of their electronic component specifications to prohibit the use of pure tin finishes in order to minimize the risks of whiskering. However, as regulations and a world economy push today’s electronics industry to use environmentally friendly (Pb-free) alternatives, the prevalence of pure tin plated components is bound to increase potentially increasing NASAs risk of exposure to risks associated with tin whiskers significantly. In an effort to evaluate risk mitigation techniques, NASA GSFC initiated experiments to study the effects of