Facile Synthesis of a Strong Ni-Based Composite Electromagnetic Microwave Absorber

A low-cost and easily prepared Ni-based composite with outstanding and efficient microwave absorption properties was synthesized via the precursor impregnation and pyrolysis (PIP) process, in which Ni foam was first soaked into a polycarbosilane/xylene solution, followed by pyrolysis under an Ar atmosphere after being dried in air. The PIP cycles showed a marked impact on the reflection loss and effective absorption bandwidth that it possessed a minimum reflection loss value of −54.96 dB at 3.35 mm with a frequency of 8.08 GHz. Besides, a superior effective absorption bandwidth from 7.20 to 11.14 GHz could be achieved with a thickness of 3.25 mm. The frequency dependence of reflection loss, impedance matching ratio, and attenuation constant was ultimately further analyzed to propose the absorption mechanism. This structure design strategy provides a new way to construct and control microwave-absorbing materials for applications in extreme environments.