|BEDNÁŘOVÁ Vlasta||VSB-Technical University of Ostrava|
|Spoluautoři LICHÝ P., LÁNA, I., ELBEL,T.|
The subject of the performed research was testing infiltration techniques to manufacture metal foams with different cellular structure. Two procedures are used to create porous metal structures: Infiltration of liquid metal into the mold cavity filled with precursors or preforms and two stage investment casting. Regular cellular structure can be achieved using different types of preforms which fill the mold cavity. Using preform like a core not filling the whole mould cavity can enable to manufacture a casting with solid surface layer and internal porous structure. The preform must satisfy a certain number of criteria. In particular it must not contain disconnected islands of material so that could be completely eliminated from solidified metal. It must be made of a material that retains its shape during liquid metal infiltration (sufficient strength, low abrasion) and could be destroyed after casting to leave the porosities. According to the two stage investment casting process, a polymer foam eg. polyurethane foam is used as a “lost foam pattern” The obtained castings are the exact replicates of the original polymer foam and dispose highest porosities (80-97%). This type of foam provides a very promising application for example in the filtration of liquid metals.