Synthesis of open-cell ceramic foam derived from geopolymer precursor via replica technique

[Display omitted] •Open-cell ceramic foams derived from geopolymer precursor were synthesized.•Accelerated solidification step at 60°C was performed to obtain dense structure.•Compression strength of ceramic foams reached ∼0.85MPa after sintering at 1300°C. This paper describes a facile and effective method for fabrication of open-cell ceramic foam derived from geopolymer precursor through replica technique. The polyurethane sponge method was applied using geopolymer mixture based on powder mixture of metakaolin/precipitated silica, potassium silica solution and fine chamotte filler. Accelerated solidification step at 60°C for 30min was performed to obtain dense structure with a good adhesion to the polymeric sponge. The effect of thermal treatment on mechanical and structural behavior of synthesized foams was investigated. X-ray diffraction (XRD) analysis indicated that no substantial differences in the content of crystalline Leucite – Potassium Aluminum Silicate phases appeared between thermally treated samples at 1100°C, 1200°C and 1300°C. It has been revealed that compression strength of ceramic foams reached 0.85±0.11MPa after the samples had been treated at 1300°C. In addition, scanning electron microscopy (SEM) and X-ray micro computed tomography (µ-CT) confirmed uniform interconnected cellular structure with pore sizes between 1 and 2mm resulting in an open porosity (εo) of 78.88vol%.