Ralph
I wouldn't expect a conformal coating to fail with a water drop, but just try it in a
humid atmosphere and see the difference. An acrylic coating is probably the best from
the point of view of humidity resistance (silicones the worst), but even it is a sieve
to humidity.
Brian
"Vaughan, Ralph H" wrote:
> We ran a similar test to the parallel trace one...used Y-coupons from pwb
> panel. Results same as previously described..Twist on the test was to also
> run an identical coupon except put 1-2 mils of acrylic conformal coat over
> traces. Even tho power/water drop was maintained, no ---migration after 2
> months. (I know speaking of conformal coat is like
> fingernails-on-chalkboard to you commercial tykes...sorry)
>
> Ralph Vaughan
> Boeing-Atlanta
>
> > ----------
> > From: Ingemar Hernefjord
> > (EMW)[SMTP:[log in to unmask]]
> > Reply To: TechNet E-Mail Forum.;Ingemar Hernefjord (EMW)
> > Sent: Friday, March 17, 2000 9:09 AM
> > To: [log in to unmask]
> > Subject: Re: [TN] Electromigration demonstration...
> >
> > Reminds of my own experiment years ago, Brian. I sent pictures to Steve,
> > would be interesting to compare. Silver migration is not anything
> > remarkable, but seemingly, few saw it happen live. /Ingemar
> >
> > -----Original Message-----
> > From: Brian Ellis [mailto:[log in to unmask]]
> > Sent: den 17 mars 2000 09:09
> > To: [log in to unmask]
> > Subject: Re: [TN] Electromigration demonstration...
> >
> >
> > Steve
> >
> > The original dendrite wizard was Charles Jennings (if my memory is good)
> > in some US
> > Govt lab (Sandia???) in the 1970s. He actually made a 16 mm film of it
> > happening (I
> > have a PAL video copy of it). He said that dendrite formation could be
> > thus provoked on
> > any substrate between any metals, but the rate and form was very variable
> > for a given
> > ionic contamination level.
> >
> > I recommend you put a 10 - 47 kilohm R in series with your battery: it
> > will reduce the
> > gas formation and keep the dendrites intact longer, because the current is
> > smaller.
> >
> > BTW, this is not electromigration, it is electrochemical migration, two
> > different
> > things. The latter is ionic in nature.
> >
> > Brian
> >
> > "Stephen R. Gregory" wrote:
> >
> > > How the heck are yew good ol' boys doin'?
> > >
> > > (Spitoooie!!)...'scuse me thar...hadda get rid of my chew, cain't talk
> > with a
> > > mouthful of terbacky...(hitchin' my bib overalls up)
> > >
> > > Anyhoo, a while back, some good ol' boy posted a simple way to actually
> > show
> > > electromigration (fancy word for us country boys ain't it) in
> > progress...you
> > > could actually see it happening. Something about using an overhead
> > projector
> > > and a 9-volt battery...or something like that.
> > >
> > > Does anybody remember that? I need some way to graphically show this
> > > phenomena happening...('nuther fancy word huh?...phenomena...)
> > >
> > > YEEEE-HAW!!!
> > > (that's good ol' boy talk for thanks a lot!)
> > >
> > > -Steve "Jethro" Gregory- (GRIN)
> > >
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