Sent from my iPad On Aug 12, 2013, at 5:45 PM, Inge Hernefjord <[log in to unmask]> wrote: > The fear of silicon in electronics has its roots in a Swedish Defence > report 50-60 years ago. At that time a military component test lab > performed tests of small signal relays. Thousands of relays were tested > with numbers of conditions. A few relays had increasing contact resistance > after thousands of operational elapsing time. Analysis gave that the > contact had small spots of some silicon product, which was never decided in > detail. The team made an anticipation, that the silicon somehow had > 'migrated' from a silicon grease that was used for some reason. The grease > was not on the PWBs, but had been creeping all over the equipment, and had > finally found its way on inside of the relays. It was called 'silicon > migration'. Relay failures were the most feared in the military boxes at > that time. Note that the relays were low contact force constructions, so > called 'tongue' relays. Power relays were not involved in the risk group. > Personally, I have analyzed hundreds of reported relays during decades, and > have never seen contact issues caused by silicon. We use silicon products > of all sorts since the 60's and have no silicon issues. I talk about > millions of boards. The academic high priests reported horrible facts > ,that increased the fear even more, e.g. a paper that concluded, that just > a few drops of silicon oil could spread over an area of a football arena in > short time! I have demonstrated my scepticism lots of times, and assured > them that the risks are pretty exaggerated. > > Inge > > > > The use of silicones for electric and electronics protection is as old as > some military application from the late 1940's. Since then the silicones > have become one of the most relevant alternatives for electronics > protection for reliable applications, and its share continues to growth due > the increase demand of current applications and the limits of organic > alternatives. > > The term "Silicone Migration" is also rather old, the first articles > talking on the subject date on early 1950's. Why then, if this phenomenon > is known and recognized for over half a century the use of silicones is > well accepted, recognized and in some cases proven indispensable? > > The "Silicone Migration" term is one almost every electrical engineer has > heard, yet very few actually know its true meaning. Often this term is used ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________