Direct Foaming Method Prepared Ceramic Foams With Controlled Structure

Ceramic foam can be applied to the fields, such as insulation, filtration, biologicalmaterials, and as the developing of the ceramic foams it is undoubtedly necessary toprepare ceramic foams with controlled structure and stable performance. The foamingprocess is a very critical process to prepare ceramic foams. The direct foamingmethod is a well-recognized simple, low-cost, but bad in the structural controllabilityto prepare foams. This paper used the cationic, anionic and cationic/anionic surfactantmixed system, through the regulation of the charge and the hydrophobic degree ofparticle surface to realize the structure controllable. Silica is as the raw materials inthis article, adding surfactant by mechanical agitation to introduce air bubbles, studydifferent surfactant systems, the viscosity, and the sintering temperature on the porestructure and the material properties, and finally to determine the experimentalparameters which have a effect on the ceramic structure. The foaming ratio, thedensity and porosity of the sintered body was tested, besides the pore structure of thesample was also observed by SEM. The experimental results showed that:(1) Respectively using anion (SDS, ABS), cationic (CTAB) and cation-anionmixed system to prepare the ceramic foams. The mixed system had long-termstability as well as good foaming ability compared with the individual systems.(2) In the cation-anion mix system, the amount of the SDS increase can improvefoaming ability. As the increasing of SDS, the pore structure slowly convertedfrom the closed to the open and the pore size becomes large. When CTABconcentration increased the foam stability was improve, and the pore structureconverted from opening to closed structure.(3) Solid content varies from35%to45%, the foam volume increased firstly andthen decreased, and the pore distribution more uniform, the pore size wasdecreased. Adding additives can not only improve the foam stability, but also beused as the binder to help increased the intensity of the training body.