[NewCandle] Anodic glow discharge SEM images

[Nick Reiter]

Thanks Keith,

Some more coming your way tonight, but alas, we drop
off the edge of the fuzzy world.

Now I MAY be able to get slightly better views by
doing a gold coating to reduce charging as much as
possible during the scans...

Anyway, I ran another soda pop can bottom, this time
with oxalic acid, to give several minutes of dim
blue-white glow.

Definite difference, and the general appearance is
that the pore size average is much smaller than with
the "yellow" glow of the phosphoric acid anodized. 
But it takes us well beyond anything I can get a good
grasp on - this is where a TEM or FESEM would need to
take over.  Me and my basic little tungsten filament
SEM toss in the hat.  I'll see if gold coating clears
her up any.

Now all of this begs the question, though, if color is
tuned by pore size of the oxide, do we really know the
mechanism by which the photons are generated?  Are we
seeing visible vacuum modes?  I'm up for a review -
what do we know about the presumed mechanism of this
luminescence?

N

--- Keith Nagel <NewCandleAdmin at ipdiscover.com> wrote:

> Hi All.
> 
> More of Nick's SEM pics. This time, the aluminum
> anode
> after glow discharge in phosphoric acid.
> 
>
http://www.kpnconsulting.com/newcandle/download/nick3.htm
> 
> You can just begin to see the pore lattice in the
> third picture.
> The lattice is disordered, probably due to the lack
> of polishing
> of the substrate and the somewhat uncontrolled
> nature of the
> anodizing. Electropolishing would help a lot; here's
> the first
> google hit with some basic info about how to do this
> to aluminum.
> 
> http://www.ep-systems.com/aboutme1.htm
> 
> The lattice pattern is a lot like a raft of soap
> bubbles. The minimum energy
> configuration
> is the regular hexagonal lattice pattern, and any
> surface variation or
> additional energy
> is reflected in a more disordered pattern.
> 
> Pity that things get blurry just when we're close
> enough to see the
> interesting structure. But good enough for
> eyeballing things. Thanks, Nick!
> 
> K.
> 
> 
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> 


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