Electromagnetic properties of pyrolytic carbon-Si3N4 ceramics with gradient PyC distribution

Pyrolytic carbon-Si3N4 ceramics (PyC-Si3N4) with gradient PyC distribution (Gradient-PyC-Si3N4) is fabricated by directional oxidation. After directional oxidation for 1.0 h, the electromagnetic absorptivity of Gradient-PyC-Si3N4 increases significantly from 0.8 to 50.1% with the obvious reduction of electromagnetic reflectivity from 99.2 to 43.8%. The Gradient-PyC-Si3N4 is a good electromagnetic absorbing material meeting the requirement of self-concealing technology.