Ceramic Foam Filters
Ceramic foam filter is a tough foam made from ceramics. Open-cell polymer foams are internally impregnated with ceramic slurry and then fired in a kiln, leaving only ceramic material. The foams may consist of several ceramic materials such as aluminium oxide, a common high-temperature ceramic, and get insulating properties from the many tiny air-filled voids within the material. Ceramic foam filters are used for absorption of environmental pollutants, filtration of molten metal alloys, and as substrate for catalysts requiring large internal surface area. Ceramic foam filters are hardened ceramics with pockets of air or other gases trapped in pores throughout the body of the material. These materials can be fabricated as high as 94 to 96% air by volume with temperature resistances as high as 1700 °C. Because most ceramics are already oxides or other inert compounds, there is no danger of oxidation or reduction of the material in ceramic foam filters.