High throughput initiation threshold characterization of BNFF

• Main Authors: Bassett, Will P., Knepper, Robert, Tappan, Alexander S., Ramasesha, Krupa
• Format: Conference Proceeding
• Language: English
• Subjects: Chemical reactions; Detonation; Impact velocity; Thick films; Thickness; Vapor deposition; Velocimetry
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/12.0034374

Understanding early chemical reaction steps in detonation environments is critical to the development of robust detonation theories and non-phenomenological models. Towards this end, we present initiation studies of 3,4-bis(3-nitrofurazan-4-yl)furoxan (BNFF), a hydrogen-free explosive with the chemical formula C6N8O8. BNFF is of interest for its unique chemistry, high detonation temperature, and formation of nanoscale carbon structures upon detonation. These studies are performed on Sandia’s High Throughput Initiation (HTI) experimental platform, using laser-driven flyer plates to rapidly investigate the reaction threshold of vapor-deposited BNFF samples as a function of thickness using photonic Doppler velocimetry diagnostics. Initial cut-back style experiments, where the thickness of the sample is reduced in order to see how far along a reaction is at a given distance into the explosive, indicate that BNFF is sub-detonative at a depth of 25 µm up to our upper limit of impact velocity at around 4200 m/s using a 25 µm thick Parylene C flyer. When thicker films, 100 – 150 µm thick, are impacted, growth to detonation begins to occur more promptly at impact velocities below 3000 m/s. Future work will involve incorporation of streak spectroscopy into the HTI platform for emission spectroscopy to further elucidate initial chemistry.