Cannot resist: For those in the rust business, rust is a product. For most
of us it is just a nuisance to be prevented.


But from somebody in the rust (iron oxide) business
(http://www.sh.com/ie/yht.htm) I found this:
Iron Oxide Yellow 313C
Specification: Matter volatile at 105 degrees centigrade (m/m)<%: 0.8 Water
soluble matter% : 0.15 Sieve residue on 0.045mm (m/m) < %:0.3 PH of water
suspension: 5.2 Fe2O3 (m/m) > %:87.1 conductivity us/cm: 175


And then a little more to confuse the issue:
Introduction
Electrochemical studies of Fe oxides have been surely initiated in corrosion
science. Formation of Fe oxides and their further reactions were
characterized in aim to learn more about corrosion resistance of steel. The
first reports were almost exclusively focused on magnetite, Fe3O4, because
it is sufficiently conductive to permit the direct study with a bulk
electrode, i.e. a piece of magnetite attached to the potentiostat, and it
yields several electrochemical reactions. Magnetite is the best starting
point to learn more about electrochemistry of Fe oxides. Lately it was found
that Fe3O4 and different polymorphs of Fe2O3 and FeOOH behave differently
(Keiser et al.).
Related to this topic is the reductive dissolution of Fe(III) oxides, whose
impact significantly exceeds the scope of pure electrochemistry (for a
review of metal oxide dissolution see Blesa et al. 1994). Reductive
dissolution is important in energy production (cleaning steel surfaces
corroded by hot water), environmental analysis (speciation of metals in
sediments and wastes) and also in the cycle of Fe oxides in natural
environment (mineral weathering, soil chemistry).
Another phenomenon studied is electrolysis of water on Fe-oxide electrodes,
which accidentally lead to discovery of oxygen insertion into Co and also Fe
oxides.
The electrochemical properties of Fe oxides are mainly controlled by two
factors: the phase composition and substitution of Fe by other metals. The
most important phases are Fe3O4 (magnetite), Fe2O3 (hematite and maghemite),
FeOOH (goethite, lepidocrocite, and few others), spinels such as MeFe2O4,
and perovskites such as SrFeO3. The commonest metals substituting Fe are Al
and Cr. The sensitivity of electrochemical properties to the oxide structure
has been proposed several times for electroanalysis, but since now other
techniques, in particular X-ray diffraction and Mössbauer spectroscopy, have
won. However, reductive dissolution of Fe(III) oxides by chemical agents is
a generally accepted analytical tool in soil and environemntal chemistry.



Good luck with the micro Siemens.

Ahne.


-----Original Message-----
From:   TechNet [mailto:[log in to unmask]] On Behalf Of Kathy Kuhlow
Sent:   Thursday, November 29, 2001 09:56
To:     [log in to unmask]
Subject:        [TN] Rusty

 << File: TEXT.htm >> I was asked a question today and I can't seem to find
the answer.  I think I know but I need more then a gut feel.

Is rust conductive, just a by product, or both?  The materials we were
discussing are phosphorus, bronze, iron.  Thanks in advance.

Kat

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