[fsonnichsen]

I have some 316 steel and some Titanium electrodes which have encountered corrosion while operating in a KCl solution. I would like to analyze the thin layer of deposit on the electrodes and would like advice on how this might be done. I realize that it probably would need to be performed by a professional laboratory but I would like to do a little reading first. (I have done some LIBS analysis here and as I expected, nothing was revealed other than the base spectrum for the metals.)
    Can anyone point me on some generic information, texts etc on the analysis of metals, esp. with regard to corrosion? (The last time I sat in a chemistry classroom was 45 years ago so I expect a lot has developed in analytical chem since then. )

Thanks
Fritz

[Mitch]

More likely than not you made the metal chloride it metal oxide at the surface. I don't know a good reference, but the chapter in electrochemistry in your freshman chemistry book should go over the theoretical aspects.

[Ithakaz]

I have some 316 steel and some Titanium electrodes which have encountered corrosion while operating in a KCl solution. I would like to analyze the thin layer of deposit on the electrodes and would like advice on how this might be done. I realize that it probably would need to be performed by a professional laboratory but I would like to do a little reading first. (I have done some LIBS analysis here and as I expected, nothing was revealed other than the base spectrum for the metals.)
    Can anyone point me on some generic information, texts etc on the analysis of metals, esp. with regard to corrosion? (The last time I sat in a chemistry classroom was 45 years ago so I expect a lot has developed in analytical chem since then. )

Thanks
Fritz

Maybe look into a Lab offering Salt Spray testing? One that conforms to MIL-STD-810 Test Method 509.5 Salt Fog

[Enthalpy]

Apparatus has been developed to analyse alloys in tiny amounts, it's even dubbed "non-destructive". In one usual process, a spark volatilizes a miniscule volume at the surface, and the resulting plasma emits light whose spectrum tells the elements present.

I suppose, but am not sure, that it will tell you the non-metals too, including O, Cl, but not H. C, P, S belong to the usual results. It will not tell a molecular composition.

One uncertainty is: what exactly will be analysed. The electrode must be free of electrolyte, including dry salt, but during the cleaning you may remove some of the deposited or grown layer.

[fsonnichsen]

Thanks for the comment on Salt Spray. I was not aware of this. Apparently this is used to test the viability of coatings on metals etc using a consistent corrosion atmosphere to somewhat quantify the  rate. It does not however offer information on the elemental breakdown of the corrosion.

[fsonnichsen]

Enthalpy--I think perhaps you are referring to LIBS analysis. I spent quite a lot of time on this a few years back---a spark is generated by a laser, the return signal intensified and the spectrum taken with a precisely gated ICCD camera. It works very well for elemental analysis, esp. for metals. Since the analyte is generally reduced to a plasma this method tends to destroy molecules. It also tends not to work very well for the non-metallic elements. I was actually considering using this at my old lab but a colleague presently has reconfigured the equipment making this difficult. My prior work however proved this to be a poor method for oxygen and chlorine.
  I am not experienced in electrical spark spectroscopy. I did build a simple 10,000V arc circuit and energized my corroded electrodes with it just to see what spectrum I might get viewing the arc near the metal. It was no surprise to see mainly nitrogen and oxygen due to the air (no vacuum equipment here). The latter of course would obscure the spectrum of the corrosion if it was due to oxidation. Thus nothing learned.
  My final take on this, in agreement with Mitch, is that this is probably an oxidation of the Ti. Ti tends to build an oxide later rather quickly, the result being that it does not oxidize further and becomes quite resistant to corrosion.
thanks all
Fritz

[EdEuban]

If you have access to an SEM use EDS or WDS.