A new approach for shielding electronics from ionizing radiation is more cost-effective than existing techniques and the secret ingredient is rust. The approach can be used to maintain the same level of radiation shielding and reduce the weight by 30% or more or maintain the same weight and improve shielding by 30% or more compared to the most widely used shielding techniques.
Ionizing radiation can cause significant problems for electronic devices. To protect against this, devices that may be exposed to radiation, such as devices used in spacecraft, incorporate radiation shielding. Weight is a significant factor in designing aerospace technologies and the shielding most commonly found in aerospace devices consists of putting an aluminum box around any sensitive technologies. This has been viewed as providing the best tradeoff between a shield’s weight and the protection it provides.
The new technique relies on mixing oxidized metal powder (rust) into a polymer and then incorporating it into a common conformal coating on the relevant electronics. Metal oxide powder offers less shielding than metal powder but oxides are less toxic and don’t pose electromagnetic challenges that could interfere with a device’s operation.
Radiation transport calculations show that inclusion of the metal oxide powder provides shielding comparable to a conventional shield. At low energies, the metal oxide powder reduces both gamma radiation to the electronics by a factor of 300 and the neutron radiation damage by 225%. At the same time, the coating is less bulky than a shielding box. In computational simulations, the worst performance of the oxide coating still absorbed 30% more radiation than a conventional shield of the same weight. The oxide particulate is also much less expensive than the same amount of the pure metal.