ERG Materials & Aerospace Corporation Duocel® Silicon Carbide Foam

The matrix of cells and ligaments is completely repeatable, regular, and uniform throughout the entirety of the material. Duocel® silicon carbide (SiC) foam is a rigid, highly porous and permeable structure and has a controlled density of metal per unit volume. Duocel® is a porous structure or open-celled foam consisting of an interconnected network of solid struts. Like soap suds or beer foam, the original bubbles that formed the foam are a three-dimensional, perfectly packed array of similar sized bubbles where each bubble has the maximum volume for the minimal surface area and surface energy. Given these common physical constraints, each bubble in the array is typically a 14-faceted polyhedral or solid shape called a tetrakaidecahedron. Once the foam is solidified, the thin membrane in each of the 14 facets or windows is removed by a reticulation process, creating an "open cell", and leaving only the thick outer perimeters of the window frames behind as a series of interconnected struts. The resulting bubble structure resembles a linked geodesic dome or "buckyball" structure where each link or strut is shared between three adjacent bubbles, thus creating the characteristic triangular cross-section. Unlike honeycomb, this open-celled structure is identical in all three directions, and is therefore considered an "isotropic" foam. Just as all the structural ligaments or struts are interconnected, the open cell porosity is also interconnected, enabling fluids to pass freely into and out of the foam structure. While technically designated as an open-celled foam, these materials are also occasionally called porous metals or metal sponge.