Synthesis, morphological and thermomechanical characterization of light weight silica foam via reaction generated thermo-foaming process

Abstract

Low-cost thermo-foaming technique involving sucrose dehydration reaction with H2SO4 has been used for ceramic foam processing. The heat and gas generated during the reaction induces a thermo-foaming effect in the sucrose-ceramic mixture. This converts the sucrose-ceramic slurry into a carbonaceous porous ceramic-scaffold. The converted carbon is seen to agglutinate with the ceramic particles. During sintering, they are removed subsequently, thereby enlarging the pores. Influence of solids-loading, sintering temperature and H2SO4 concentration on the foaming behaviour, pore morphology and thermo-mechanical properties are studied. The fabricated silica foams are found to have porosity within the range of 70 %− 90 % and compressive strength of 0.8–2.8 MPa. The extreme porosity of the silica foams and their intercrystallite pores within the struts results in the low thermal conductivity (0.0943 Wm−1K−1) of the specimens. The fabricated foam is seen as a promising material for insulation applications like catalyst supports, filters and bio-scaffolds. © 2022 Elsevier Ltd