Developing 3D-Printable, Reactively-Formed Electrical Conductors

Self-propagating high-temperature synthesis (SHS) in macroscale structures is an effective method of creating high-temperature materials directly. In nanostructured, micro-scale materials, SHS has been thoroughly explored for rapid liberation of heat, where short diffusion length-scales enable very low ignition thresholds. For instance, materials such as Al/Ni multilayers have been demonstrated to be extremely versatile micro-heat sources to enable <i>in situ</i> bonding, sealing, and ignition of additional energetic materials to name a few applications. As presented at previous meetings, Draper has developed a platform which harnesses both these aspects of SHS – using SHS to form a conductive, high-temperature, carbide, and harnessing the reaction heat to reflow a highly electrically-conductive matrix phase. Together, this enables the production of 3D-printed electrical conductors <i>in situ</i>. In this talk, we summarize the process by which material systems were considered, discarded, and selected; the development and fine-tuning of our reactive particles; and the ultimate performance (and limitations) of the final materials. We will delve into the serendipity of how an erroneous phase diagram played a crucial role in our development process, and the years-long, multi-continent process it took to uncover the flaw. Finally, we will cover future applications and pathways, both at Draper and beyond.