**2. Processing routes to porous ceramics**

The processes for manufacturing porous ceramics can be classified into following four categories, which is schematically depicted in Fig. 2.


In this chapter, we reviewed the main processing techniques that can be used for the fabrication of porous ceramics with tailored microstructure. Replica techniques, sacrificial template, and direct foaming techniques is described here and compared in terms of microstructures and mechanical properties that could be achieved. These simple yet versatile approaches give rise to porous ceramics with unique microstructural features that control the properties and functions of the ceramic materials.
