Carbon Foam Tooling
Carbon foams are attractive candidate materials for molds because of their low density, coupled with either very high or low thermal conductivity. Unfortunately, carbon foams are usually not adequate for many high-temperature applications because of strength-to-density requirements. In addition, open-celled carbon foams with highly interconnected pores have porosities,making them unsuitable for such applications. Cladding of carbon foams has been suggested as a means to improve their usefulness as tooling materials. Joseph and Rogers (US Patent No. 6,849,098) covered the foam structure having highly interconnected, open-cells with so-called `facesheet` materials. These facesheets either completely or partially fill the cell volumes. However, filling cells with facesheet materials will increase the density of such foams and consequently reduce their suitability as lightweight materialsfor use in composite tooling. (RDC 10/9/2010)
(Shao and Kaschak, US Patent 7,776,430, 8/17/2010)
Recent US Patents
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8/17/2010
7,776,430
Carbon foam tooling with durable skin
Shao and Kaschak of GrafTech have developed carbon closed-cell foam molds by sealing the surface with a carbon-filled cement and electroplating the surface to form a mirror-like finish. This foam has a density of 0.05 to about 0.8 g/cm3with a compressive strength of 2000 psi.