The material can absorb electromagnetic radiation emitted by electronic devices. Credit: Ron Lach/Pexels
A composite material can absorb potentially harmful electromagnetic radiation emitted by devices such as smartphones, tablets and microwave ovens1.
Cell phone chips, medical devices and electronic systems mounted on aircraft could be coated with the material to reduce emissions and shield other instruments from interference, reports a team at the CSIR-Advanced Materials and Processes Research Institute in Bhopal.
The scientists synthesised the material by depositing nickel oxide and carbon nanofibre on a foamy structure of aluminium. Adding the metal oxide and nanofibre to the aluminium enhanced its resistance and reduced its conductivity, allowing it to absorb radiation.
Analyses showed that a large number of electromagnetic waves could penetrate the porous structure of the foam. The team, led by Shiv Singh, found that it lost energy by scattering and absorbing the waves.
This energy loss reduced the material’s ability to reflect the waves. It could only reflect a limited number of waves, with negligible transmission through it, and absorbed almost 98% of the waves passing over it.
The researchers attribute this absorption to a possible molecular mechanism. The nickel oxide and the nanofibre act as a barrier in the conducting network of the aluminium foam, which restricts the hopping and migration of electrons, causing a drop in conductivity. This attenuates the waves through absorption.
