Reinforced Cellular Carbon Matrix–MgO Composites for High Temperature Applications: Microstructural Aspects and Colloidal Processing

The main potential of functionalized cellular carbon refractories is the considerable variation range of cell dimensions, cell geometries, i.e. spatial arrangement of interconnected carbon strut networks, as well as cell compositions, i.e. layered or multilayered cell conformations. In order to achieve this last goal, it will have to provide available post-processing procedures to upgrade cellular carbon matrices for specific functions, i.e. tailored moduli of elasticity, thermal shock resistance, that cannot be technically or economically provided by conventional low carbon MgO–C refractories.1 Here we report different colloidal synthetic processing routes for tailoring reinforced cellular and reticulated glassy carbon structures in the macro-, meso-, and microscale, which then gives rise to very high thermal shock resistance characteristics. The cellular interconnected glassy carbon network is processed by replication of PU foams with phenolic resins and subsequent carbonization in inert atmospheres. In order to improve the water-wettability of tailored glassy carbon cellular matrices and to ease the subsequent infiltration of aqueous MgO suspensions into open porous, cellular carbon structures a low cost YSZ, and SiC coating concept is proposed using an electrophoretic deposition (EPD) method and subsequent sintering in order to achieve the reinforcement of carbon phase, respectively. These as-received wettable and reinforced coatings and functional layers on the interconnected cellular glassy carbon network are able to reliably allow the infiltration of aqueous MgO suspensions to build up low carbon functional C/SiC- as well as C/YSZ–MgO refractories with designed and controlled thermo-mechanical properties.