Virtually any material that can be deposited by chemical vapor deposition can be used to infiltrate a foam and coat the ligaments. Once the coating fills ~5% of the original pore space, the mechanical, thermal, and electrical properties of the whole are dominated by the properties of the coating.
Among the materials that can be deposited are pyrolytic carbon or graphite, refractory metals (e.g. niobium, tantalum, tungsten, molybdenum, and rhenium), and ceramic compounds (e.g. the oxides, nitrides, carbides, borides, and silicides of the metals).
Foam-core sandwich structure in which fully dense silicon carbide facesheets are integrally bonded to 80-90 vol% porous, open-cell silicon carbide foam (both 5x). Refractory metal foam/facesheet structures are also feasible.