Macro-structural Control of Gradient Macro-porous Ceramics via Direct-foaming Process

Highly macro-porous ceramics with relatively dense surfaces have been successfully fabricated using the powder-based direct foaming process that employs thermosetting phenolic resin powder as foaming agent and binder for the ceramic powder. When foaming on the surface is suppressed by using filter paper, highly porous structure with denser surface could be simultaneously fabricated in one foaming process. Macro-porous ceramic with denser surface is obtained through conventional sintering process. This article briefly reviews these fabrication processes and key factors affecting the porous structure. The highly macro-porous ceramics with a denser surface are also characterized by bending strength measurement and microstructural observation.