Leveraging high heating rates to attain desirable reaction products in Al/Zr/C nanocomposites

Reactive nanolaminates are a class of energetic materials which store significant chemical energy in their heterogeneous microstructure that comprises alternating nano-scaled layers of two or more reactants which can undergo self-propagating exothermic reactions to form stable compound phases. We previously observed that the products of self-propagating formation reactions in Al/Zr/C nanolaminates differ dramatically from those obtained after heating slowly to any temperatures up to 1450 & DEG;C. Here we explore this heating-rate dependent phase formation in Al/Zr/C reactive nanolaminates through a combination of nanocalorimetry coupled with in situ synchrotron X-ray diffraction, as well as a suite of ex situ analyses. Specifically, we show that forming a cermet of ZrC + Al requires either a sufficiently high heating rate (such as is present during a self-propagating reaction) or quenching from high temperatures (� 1600 & DEG;C), demonstrating the utility of high heating rates to produce desirable phases. & COPY; 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).

Automated summary

Reactive nanolaminates are energetic materials with heterogeneous microstructures that undergo self-propagating exothermic reactions to form stable compounds. This study investigates the phase formation in Al/Zr/C reactive nanolaminates under different heating rates using nanocalorimetry, synchrotron X-ray diffraction, and ex situ analyses. The results reveal that high heating rates or quenching from high temperatures are required to produce the desired ZrC + Al cermet phases.