Pyrophoric materials ignite spontaneously upon exposure to air and have application as cathode materials for fuel cells, active agents in chemical sensing devices, catalysts for ammonia synthesis, liquid-phase hydrogenation reactions for fine chemicals, and groundwater remediation. Some passivated pyrophoric iron materials have found applications as pigments for magnetic tapes and in medical practice for their bacterial killing properties.
In the military, pyrophoric iron materials have long been considered as the primary pyrotechnic charges in ammunition training round markers and infrared aerial decoy devices (countermeasures) against heat-seeking missiles.
The particle size of these materials is a key to how hot and fast they burn such that smaller size particles interact more with the air and thus burn hotter and faster. An ideal pyrophoric particle would be nano-sized but such particles tend to clump together during processing thereby decreasing their reactivity.
But Army researchers have recently developed a pyrophoric foam material made in a one-pot process in which the metal particles are uniformly dispersed, without solvent.
This material is produced as a paste and can be molded or cast into any geometry. Thermal treatments to the precursor metals produce metal nanoparticles formed through simultaneous carbonization of the polymeric matrix. Upon contact with the air, the foam materials are highly pyrophoric and burn intensely. Both the pyrophoric iron nanoparticles and the microporous carbon matrix are highly flammable and contribute to the total heat output.
- Pyrophoric foam composition can be molded and fabricated into predefined geometric shapes prior to thermal activation such as pellets, thin disks, beads, granulars, monoliths with large channels and cavities
- The ratio of the precursor chemicals to produce the microporous foam can be adjusted to achieve a targeted loading of the metal particles for tunable pyrophoric properties
- US application number 20170137340 available for license
- Potential for collaboration with Army researchers