Enhanced Electromagnetic Absorption Properties of Novel 3D-CF/PyC Modified by Reticulated SiC Coating

A novel hybrid foam composite consisting of the three-dimensional (3D) interconnected carbon foam (CF) and ultrathin silicon carbide (SiC) coating was prepared via the carbonization, chemical vapor infiltration, and chemical vapor deposition process. By means of incorporating the pyro carbon and SiC coating on the surface of the CF skeleton, not only the thermostability and compression resistance but also the electromagnetic absorption performances of the as-prepared composites were enhanced. The results were that the novel hybrid foam was thermostable, as beyond 87% weight remained in the air atmosphere at 700 °C, and the strong compression strength explored the potential application in the critical environments. As expected, the foam possessed an excellent electromagnetic absorption property with the minimum reflection loss of -37.189 dB at 13.92 GHz at 2.0 mm. It indicated that the SiC coating with bridged junctions, twinning interfaces, and abundant stacking faults took great effect on the improvement of the electromagnetic absorption property, as well as the contribution of the 3D open-cell network.