Re: Useing nickle in tungsten boat
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Aurigema, Andrew N. (KSC-ASRC-491)[ASRC AEROSPACE]
I agree.? That deep purple coating is only about 40% reflective
but it is very tough.? I coated my secondary a little wrong about 2 years ago
and it still looks perfect¡¡. But is only 40% reflective.? So if can go less on
the power and let the aluminum evaporate away the tungsten will stay behind as
nasty looking crystals.
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Drew
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From:
VacuumX@... [mailto:VacuumX@...] On Behalf Of Thomas
Janstrom
Sent: Sunday, April 04, 2010 8:33 AM
To: VacuumX@...
Subject: RE: [VacuumX] Re: Useing nickle in tungsten boat
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That¡¯s why Kevin at Mid Western Tungsten
recommended the alumina coated tungsten boats, nickel wets tungsten a little
too well shall we say¡.
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Funny but aluminium does this too, but
the low BP means you get, in effect, fractional distillation happening leaving
the W behind as the dissolved aluminium evaporates out of solution. Too much
power (my best guess after much thought) and you can actually evaporate an
aluminium/tungsten complex that will deposit out giving blue black coatings.
Just ask Drew in Sunny (?) Florida.
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Cheers, Thomas Janstrom.
Little Gems.
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