| Popis: |
The chapter represents the porous metal and metallic foam characterizations and their production techniques. The material selection, powder preparation, compaction methods, and sintering of porous metal powder are considered to obtain the porous powder with desired porous characteristics and mechanical properties. Major application areas of porous PM materials are summarized. The PM technologies that allow the production of metallic foams with density values ranging from 0.2 to 2.0 g/cm3, are considered. The Alparas, Hydro/Alcan, Formgrip/Foamcast, Gasar, and Foaminal/Alulight technologies for closed-cell metallic foam production are discussed. The investigation results of various foaming agents, including TiH2, magnesium hydroxide, magnesium carbonate hydroxide, magnesium carbonate, dolomite, calcium carbonate, etc., as well as the techniques based on the spacer materials NaCl and KCl are considered. The synthesis of open-cell metal foams, accomplished by investment casting, an open-cell mold, electrolytic deposition, chemical or physical vapor deposition on polymer templates, and the PM route, are discussed. Metallic foam materials for structural and functional applications, including high temperature-resistant materials and biomaterials, and their properties (mechanical, acoustic, energy absorption, thermal, and permeability) are considered. The typical structures of porous metals and metallic foams are displayed by SEM and TEM micrographs. |
