Hierarchically cell-window structured porous cordierite prepared by particle-stabilized emulsions using potato starch as a modifier

A review on recent development of foam Ceramics prepared by particle-stabilized foaming technique

Particle-stabilized technique for fabricating foam ceramics was developed in 2006. Porous ceramics with porosity over 95% can be prepared by this newly developed method. This foaming technique was derived from the principle of Pickering foam to a large extent. The high internal phase volume, narrow distribution of pore size as well as the structural stability of the Pickering system enable the final ceramic products to realize their functionality in a variety of applications. However, the interfacial aspect of the foaming system determines the final product in many ways, which brings this novel method details to explore and possibilities to challenge. The current review introduces the particle-stabilized method combining with colloid and surface science since particles are the building block of ceramic materials. The history of this newly invented method was mentioned at first, followed by foam ceramic products prepared by this foaming technique combining with corresponding mechanism. Some representative applications involving ceramic materials made by particle-stabilized method were discussed. At last, we conclude the overall article and put forward some outlooks and challenges about the future direction of this unique foaming technique.

Structure-Controlled Porous Cordierite Ceramics with High Solid Content Prepared by Pickering Emulsion Technique Using Sucrose as a Porogen

Porous cordierite ceramics (PCCs) with stable 3D microstructures were prepared by Pickering emulsion technique using sucrose as a porogen. The microstructural and mechanical properties could be adjusted by varying O/S ratios, sintering temperature, and sucrose content. The formation of the spherical structure was due to the broken oil bubbles. The appearance of cordierite and the concurrent consumption of sucrose were responsible for the observation of gradient pore structure. When the O/S ratio was 2, the pore-structure-controlled PCCs with cordierite as the main phase was obtained after sintering at 1300 °C. With the addition of 30 wt.% of sucrose, the obtained PCCs possessed high solid content of 45 vol.%, the porosity of 90.83%, the compressive strength of 6.09 MPa, and the optimized thermal conductivity of 0.4794 W/m.K. Compared with the predecessors' research results, the as-prepared precursor of PCCs with sucrose content had the lowest initial Zeta potential without adjusting the pH to ensure the stable suspension. Our results showed that the addition of sucrose not only acts as a solvent to increase the solid content, but also acts as a pH modifier to maintain precursor stability, which enables the increase in compressive strength. In this work, via the scenario of "oil droplet" 3D accumulation, the stable and orderly spatial arrangement of the micro-emulsion system was successfully realized to obtain the structure-controlled PCCs by controlling the precursor conditions.