Tailored metastable metal/ceramic nanocomposites in carbon-based scaffolds as next-generation energetic nanomaterials (ENMs)
Abstract
Energetic nanomaterials (ENMs) find applications in solid-state propellants, explosives and pyrotechnics due to the anticipated kinetically controlled ignition arising from large specific surface areas, metastable structures and smaller diffusion lengths in nanoscale regimes. Past works have investigated energetic properties of metal nanoparticles (NPs) (Al, Ni, Si, etc.) and composite Al/oxidizer mixtures, including PIs own work on the use of nano-Al in explosives and pyrotechnics, that provided fundamental understanding on size-dependent properties and heat release mechanisms at nanoscale. Yet, the large heat release in first-generation ENMs have been offset by hindered detonation rates due to the fuel-oxidizer diffusion lengths and rates being compromised by excessive oxide shell formations and NP aggregations. To this end, few research efforts have tapped into the unique yet, diverse possibilities of tuning the reactivity of composite ENMs by tailoring their metastable states andsurface structural rearrangements in organic/inorganic fullerene-like shell-core nanostructures that can lead to excess internal stresses while preserving the active or metastable cores, and can be safely activated at desired conditions. Although such efforts would be novel and commendable, weak fundamental understanding and challenges in the design and synthesis of next-generation metastable ENMs whose surface reactivity can be tuned via structural arrangements of interfacial atoms have stymied their potential as future ENMs. The current proposal aims to address the aforesaid knowledge gap via rational design, synthesis and structure-property characterizations of composite metal/ceramic (Al/Al4C3) NPs (<10nm) encapsulated in fullerene-like (onion-layered) Carbon nanocages. High-energy laser ablation synthesis techniques shall be used for manufacturing the composite ENMs whose energetic behaviors will be tailored by tuning their metastable states/interfaces, compositions and crystallinity. Structure-composition properties evolving out of the complex plasma process will be tailored via detailed mechanistic understanding for the chemical dynamics and reaction mechanisms during laser ablation synthesis as developed from in-situ laser-induced breakdown spectroscopy measurements. One can easily envision that such efforts shall pave the path for the design ofadvanced ENMs, wherein active NPs with metastable metal/ceramic interfaces are encapsulated in fullerene-like shells under exceedingly high pressure and stress such that their energy release, surface reaction rates and energetic behaviors can be kinetically controlled even under harsh activation conditions. The grand challenge science evolving from the proposed work will provide fresh paradigms in the rapid discovery and deployment of novel metastable NPs that can be immediately extended to diverse families of metal/ceramic composites including Al/Al4C3, Al/AlN, Al/h-BN and/or c-BN systems. Such efforts will also pave the path for systematic design ofthe much-elusive structural bond energy release (SBER) materials in future. Beyond their deployment as ENMs with enhanced safety and reduced sensitivities for US Armys missions in munitions/weapons applications, such metastable composite ENMs will also find diverse defense applications including NCs for armor protections under harsh conditions, micro-manufacturing, energy storage, and lubricants in wear/corrosion protections.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 05, 2021
- Source ID
- N000142112507
Entities
People
- Dibyendu Mukherjee
Organizations
- Office of Naval Research
- United States Navy
- University of Tennessee