**Porous Ceramics**

Naboneeta Sarkar and Ik Jin Kim

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/61047

#### **Abstract**

The unique chemical composition and microstructure of porous ceramics enable the ceramic products used in a number of applications such as filtration of molten metals and hot corrosive gases, high-temperature thermal insulation, support for catalytic reactions, filtration of diesel engine exhaust gases, etc. These applications take advantage of special characteristics of porous ceramics such as low thermal mass, low thermal conductivity, controlled permeability, high surface area, low density, and high specific strength. In this chapter, we emphasize on direct foaming method, a simple and versatile approach that allows fabrication of porous ceramics with tailored microstructure along with distinctive properties. Foam stability is achieved upon controlled addition of amphiphiles to the colloidal suspension, which induce in situ hydrophobization, allowing the wet foam to resist coarsening upon drying and sintering.

**Keywords:** Porous ceramics, direct foaming, wet foam stability, Laplace pressure, adsorption free energy, microstructure
