Composites is general term, normally used when Carbon fiber is mixed with metal alloys.Does composites automatically mean Radar Absorbent Material (RAM)? Or RAM are special type of composites?
RAM are special compositions. There are several RAM compositions. They work by converting EM waves into heat energy. Which is then dissipated into air through frame of the aircraft.
Different alloys are used with mixtures of nano CF and Carbon black in different RAMs.
A specific RAM can't absorb all the waves in different frequencies.
A good read would be "Carbon black", "Metal ball paint", "Ferrofluids", "carbonyl iron". Only after clearing these thing you can understand further.
RAMs of different ferromagnetic particles can be mixed inside a carbon fiber weave, but of course we have limit.