Formation of Additive-Containing Nanothermites and Modifications to their Friction Sensitivity

Abstract

Nanothermites can provide high energy densities and reaction rates but can also display extreme friction sensitivities. Additives that provide friction modification offer the potential to reduce the friction sensitivity of nanothermites. In the present work, MoS2, graphene, and hexadecane additives were dispersed in MoO3 prior to nanothermite formation with the aim of reducing friction sensitivity. Nanothermites were subsequently prepared using a palmitic acid–passivated nano-aluminum (L-Al) and additive-containing nano-MoO3 by the resonant acoustic mixing of dry powders. In general, the incorporation of additives results in a reduction in friction sensitivity with the baseline minimum ignition friction rising from 10 to 120 N using 0.5% wt/wt micrometer-sized MoS2 or 5% wt/wt hexadecane. However, the relationships between loading and performance are complex and vary by additive; for example, the friction sensitivity dependence using micrometer-diameter MoS2 displays a maximum at 0.5% wt/wt and declines to 7 N using 5% MoS2.