Every foundry manager knows that inclusions lead to poor casting surface quality, deterioration of mechanical properties, poor machinability, casting permeability, and gas bubbles. Fortunately, there are ceramic-foam filters to address these problems.

Ceramic-foam filters — which look very much like sponges — are characterized by an open-pore reticulated structure with porosity that exceeds 90% and a very high surface area. This structure offers low resistance to fluid flow, making it useful as a filter. When molten metal flows through a ceramic-foam filter, it takes a tortuous path, effecting the removal of very small inclusions by attraction and adsorption to the internal ceramic-pore structures. The structure works so well, in fact, that ceramic-foam filters are the most efficient filters for removing inclusions from molten metal.

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