triforcharity: As I understand, our influence (if any

) on the planned work of Jim Millette (from the choice of methods up to the interpretation of results) should be as minimal as possible. Later on, a thorough discussion in JREF seems to be inevitable
Oystein: Although this thread is on paints and not thermites

, it is always good for me to learn something new even in the field of pyrotechnics. Linked Kevin Ryan's video provoked me to read an original paper on Al/Fe
2O
3/Viton fine thermites prepared by
Gash et al (better late than never

)
Some remarks:
- As regards determination of aluminum (one of the things of our interest), it is written in the paper that elemental aluminum in used UFG (ultra fine grain) Al was determined by thermogravimetric method. There are no details provided but I expect that aluminum powder was heated on air in TGA device up to high temperatures and metallic aluminum was then determined from the increase of weight (caused by oxidation of Al to Al
2O
3). Btw, there was about 70 % of elemental Al in these UFG powders. Of course, this method is not applicable to red-gray chips, containing lot of organics (and other stuffs).
- This is one of the examples of thermites in which not only some polymeric binder is used, but it is used as an active component (contributing to thermitic reaction). More specifically, about 10 wt% of Viton A was present in Gash'es thermites. As other fluoropolymers, Viton is an exceptional polymer in sense that it contains mostly bound fluorine instead of hydrogen (around 60 %), which greatly increases its thermal stability (remember just Teflon and its wide use for kitchenware). Even Viton, however, degrades massively at temperatures between ca 475 and 500 degrees C and it is completely degraded/vaporized at 550 degrees C (see
http://www.rtvanderbilt.com/documents/MSDS/US/vit006a.pdf, p. 5).
- To be honest, I have so far no idea how Viton (and similar fluoropolymers) participates on the thermitic reaction. It is only written in the paper that this polymer acts as "a strong oxidizer". Notably, gaseous products are formed in this case (in contrary to purely inorganic thermites). It implies (among others) that we should be careful enough in claims like "thermite can't contain a substantial amount of any polymeric binder" and "any thermite does not release any gaseous products during burning".
Viton has characteristic FTIR spectra (see paper) and its fluorine (present in a great amount) may be detectable by XDES, but I am not sure. Anyway, this is not important for paint theory.
Perhaps these things had been already mentioned elsewhere; if yes, sorry.