[NewCandle] Nick's SEM photos of his aluminum corrosionexperiments

[Nick Reiter]

Hi Keith,

Therein is the great debate about EDS among thems as
uses it.

The old rule of thumb of most operators I know is that
less than about 1% is pretty much a toss - in the
noise, as it were.  Some elements appear to give
spectra of a little more distinction, particularly as
you go higher in energy.  Some labs say .5 or even .2%
can be realistic.  Others refuse to give credence to
anything less than 2%.

I've seen distinct peaks that the semi-quant assigns a
value of .2 or .3 %  And I've seen very tiny hard to
fish out peaks of B, N, C, F that come back having
startlingly parge values assigned to.

Honestly, I may have left O out of the quant in some
scans because its liable to be present so universally.
 I may have not been as consistent as I should in
either including it or removing it.

The iron is there in the quant box of the control
sample scan - 1.09%at.

The real pro techniques for analysis less than 1% are
atomic absorption, ICP, glow discharge mass spec, SIMS
and Auger.  I may be getting ICP in next year's
budget.

nnnnn

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

> 
> >Yes, I know.  So, where's the iron coming from?
> 
> There's a peak for iron in the control spectra, but
> it's not
> reflected in the mass percentage analysis? The Al
> would
> be corroded preferentially w/ respect to the Fe,
> leaving
> an Fe enriched layer.
> 
> I have a related question about the control foil.
> Why is there
> no oxygen in the analysis? We know there is an oxide
> layer
> on the aluminum by virtue of it's having been
> exposed to air.
> Yet no O is present in the analysis? Are the values
> really good to .01%???
> 
> K.
> 
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