Microscale Electrostatic Discharge (ESD) Sensitivity Characterization of Energetic Materials

Prior to formulating and large-scale testing, all novel energetics must undergo a variety of safety testing, including characterizing the electrostatic discharge (ESD) sensitivity, where the material is exposed to a spark discharge-generated shockwave at varying energy levels to determine the ignition threshold. The current standards for these tests include a variety of technique implementations and subjective and operator-dependent go/no-go criteria. As a result, values reported for the same material vary widely across different laboratories. Furthermore, these tests typically require grams of material to complete, which is typically unavailable during the early development process when only milligrams are synthesized at a time. Waiting to test until after developing scale-up procedures is nonideal since it is often too late to modify the synthesis procedure without significant additional cost and labor; if the material does not pass, it is often abandoned. Therefore, an objective microscale method to pre-screen the ESD sensitivity of novel energetic materials was developed in our laboratory. The required amount of material is reduced by an order of magnitude (less than ten milligrams per test) and objective go/no-go criteria are incorporated, including time-resolved integrated emission measurements, emission spectroscopy, and high-speed imaging. This presentation details our unique microscale ESD sensitivity procedure and provides example characterizations of aluminum powders.