Direct foaming

There are also two variants of the direct foam moulding process the so called hot moulding process and the cold moulding process. 

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

Figure 1. Typical porosity and average pores sizes achieved via replica, sacrificial templating, and direct foaming routes. ...

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. 

Figure 3. In situ hydrophobization of particles and solid foam formation by direct foaming. ...

The total porosity of directly foamed ceramics is proportional to the amount of air incorporated into the suspension or liquid medium during the foaming process. The pore size, on the other hand, is determined by the stability of the wet foam. High-volume foams are formed upon mechanical frothing which strongly indicates the stabilization of air bubbles due to the attachment of particles to the air-water interface. 

Figure 26. Microstructures of porous ceramics using 0.15 mol/L of (a) propionic acid, (b) butyric acid, and (c) valeric acid the inset in (a), (b), and (c) show single dense struts obtained with direct foaming method ...

Direct Foaming In Direct Foaming techniqne (Studart et al., 2006), a ceramic-based suspension is foamed by gas incorporation (physical or chemical... 

Porous ZrB -Based Components Prepared by the Direct Foaming Method A Special Case Clot Forming... 

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