Powder compacts and green bodies for porous materials

Abstract

Porous ceramics or metals with pore size from sub-microns to sub-millimeters have been produced conventionally by sintering powder compacts. These porous materials have been used in industrial applications such as filters, catalysis beds and gas sensors. Powder compacts usually have open porosity of around 0.5. Porous materials can be obtained by partially densifying powder compacts. In order to produce open porous materials with desired properties, it is necessary to control powder properties, green body properties and sintering processes. In particular, powder compacts and green bodies are very important in the fabrication of porous materials with desired properties. Here the term ‘green’ or ‘green body’ means a presintered body which is an as-formed body from powder or fiber. These methods of obtaining densified materials are often different from those for sintering porous solids. In this chapter, each process in sintering for producing porous materials is described.