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-temperat ure synthesis of powders. These silicides can also be formed from vapor dep osited reactive multilayer foils. The foils typically contain hundreds of l ayers that alternate between two elements that will mix exothermically to f orm a compound. Once the formation reaction is ignited in a foil, it can se lf-propagate along the foil with a controlled velocity. This paper investig ates self-propagating formation reactions in Nb;Si multilayers and demonstr ates that their reaction velocities decrease as the individual Nb and Si la yers thicken. The paper also explores the feasibility of forming the vapor- deposited foils, during reaction into complex shapes. (C) 1999 Elsevier Sci ence S.A. All rights reserved.