Self-propagating formation reactions in Nb/Si multilayers

Structural silicides with promising high temperature mechanical properties can be fabricated into near-net shapes using self-propagating high-temperature synthesis of powders. These silicides can also be formed from vapor deposited reactive multilayer foils. The foils typically contain hundreds of layers that alternate between two elements that will mix exothermically to form a compound. Once the formation reaction is ignited in a foil, it can self-propagate along the foil with a controlled velocity. This paper investigates self-propagating formation reactions in Nb/Si multilayers and demonstrates that their reaction velocities decrease as the individual Nb and Si layers thicken. The paper also explores the feasibility of forming the vapor-deposited foils, during reaction into complex shapes.