[WIP]SKIN: SH5 Tarnmatte Anechoic Coating

[aergistal]

I see what you mean by refined now. Yet oxide does not equal rust. Rust is just a common term and is misleading.

My bet is on magnetite Fe3O4 (iron (II,III) oxide).

Conclusions
[...]Magnetite proved the best absorber of electromagnetic waves in the single frequency that was tested. Hematite* had some microwave absorbing properties but not as good as magnetite.

Synthesis and Characterisation of Radar Absorbing Nanocomposites
http://www.met.kth.se/utbildning/4H1...dar%202006.pdf

*Hematite is the red iron oxide.