Effect of chemical vapor infiltration treatment on the wave-absorbing performance of carbon fiber/cement composites

Abstract

Short carbon fibers were treated at high temperatures around 1100°C through chemical vapor infiltration technology. A thinner layer of pyrocarbon was deposited on the fiber surface. The dispersion of carbon fibers in a cement matrix and the mechanical properties of carbon fiber/cement composites were investigated by scanning electron microscopy (SEM) and other tests. The reflectivity of electromagnetic waves by the composites was measured in the frequency range of 8.0–18 GHz for different carbon fiber contents of 0.2wt%, 0.4wt%, 0.6wt%, and 1.0wt%. The results show that the reflectivity tends to increase with the increase of fiber content above 0.4wt%. The minimum reflectivity is −19.3 dB and the composites exhibit wave-absorbing performances. After pyrocarbon is deposited on the fiber, all the reflectivity data are far greater. They are all above −10 dB and display mainly wave-reflecting performances.