Microwave ignited combustion synthesis of intermetallic-based functionally graded materials

Combustion synthesis (CS) of different functionally graded materials (FGMs) based on intermetallic alloys were ignited by 2.45 GHz frequency microwaves, in order to obtain candidate materials for high temperature structural and coating applications. Combining CS with a moderate pressure, to promote porosity reduction, it was possible to obtain both freestanding samples and hard coatings on non-ferrous alloys substrates. The high temperature generated due to the high exothermicity of CS, and the selective microwave absorption by the reacting species, led to the formation of complex binary and ternary compounds and microstructures, at the interface between the reacted powders and the substrate, presenting, in some cases, an increased micro-hardness value with respect to parent materials