Magnetite

Abstract

Magnetite, Fe3O4, is a naturally occurring, safe iron oxide with an unusual and useful combination of properties compared to the better-known functional fillers for plastics. It is used to make high-density compounds for sound damping, particularly in automobiles, and also to lend heft, that is, the impression of quality. It is able to block x-rays and other types of radiation, making it useful as a nonhazardous replacement for lead-based blocking materials. A very high volumetric specific heat capacity allows it to absorb and release large amounts of heat energy, which is useful for green buildings. It is microwave and induction heatable, suggesting potential in cooking applications. Thermal conductivity is useful for heat dissipation in electrical devices and electricity conductivity allows it to be used as a permanent antistatic additive. Natural magnetite is composed of hard, angular particles that can enhance slip resistance of polymer flooring. Last, but not least, it is strongly attracted to magnets, so it can be used to impart magnetic properties to plastics. Applications of this multifaceted and relatively unknown specialty filler continue to expand.