[AR] Re: Tin whiskers
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Thu, 4 Aug 2016 14:02:35 -0400 (EDT)
On Tue, 2 Aug 2016, Norman Yarvin wrote:
They also help against whiskers that are floating around...
Generally better addressed by excluding such conductive debris, i.e. by
being more careful about materials choices and cleaning.
With all the little parts that come galvanized, that isn't a small task.
(The presentation I linked to shows a D-sub connector with a zinc-plated
shell with whiskers growing. "What additives quench zinc and cadmium
whiskers? We don't know, but certainly NOT chromate conversion
finishes!")
It's not a small task, but it's often necessary anyway. Cadmium and zinc
platings are ground-ruled out for most space hardware because they have
noticeable vapor pressures, especially when they're in an area that runs
warm, and can evaporate (!) and recondense in inconvenient places. See
<
http://nepp.nasa.gov/npsl/Prohibited/zinc_prohibition.htm> and
<
http://nepp.nasa.gov/npsl/Prohibited/cadmium_prohibition.htm>.
Henry
Other related posts:
