Analysis Solid State Chemical Reactions
Composite materials are, by definition, multi-phased.Quite often these phases are not distinguishable by optical microscopy. Raman analysis provides very rapidanalysis that can differentiate phases, even closelyrelated phases such as polymorphs of a given composition,or differing stoichiometries in a solid system. Recently a SiC conversion coating on a carbon-carbon composite used in the space shuttle was analyzed andvarious phases were mapped. The identification of phases, in combination with maps showing the physical proximity of the phases, provide insight into the solid state chemicalreactions that produce the multi-phase coating.