Performance And Testing Of Foam Ceramic Filters

Foam ceramic filters should possess good strength at room temperature, preventing slag shedding during transportation and operation; they should have certain high-temperature strength, thermal shock resistance, and resistance to molten metal erosion; they should have good chemical stability, not reacting with molten alloys; they should have suitable pore size, good permeability to molten alloys, and the ability to filter non-metallic inclusions; and they should have good appearance quality, such as no deformation, small dimensional deviations, uniform pore size, and no clogging.

Permeability is one of the important performance indicators of filters. It not only affects the pouring speed during the casting process but also the effectiveness of inclusion removal. Air is typically used as the fluid to test the filter's permeability. Compressive strength is an indicator of its mechanical properties; for example, a 22 mm thick filter can have an average compressive strength of 2.7 kg/cm².