Microstructural Tailoring of Thermal Shock Resistance in Refractory Materials

Viscoelastic crack bridging is an efficient toughening mechanism improving the resistance to creep and thermal shock in refractory materials. Viscoelastic bridges have the net effect of shielding the crack tips from transient thermal stresses due to thermal shock.

This work describes the role of different aggregates and cordieritic matrix formulations in the thermal shock resistance of cordierite–mullite materials. The formation of viscoelastic ligaments can be promoted by tailoring the magnesia, molochite, fused silica, and alkali content in the refractory batch to promote the occurrence of a higher amount of glassy phase in cordierite–mullite refractory materials. Specimens containing different wt% of fused silica, mullite, and cordierite grogs have been prepared and characterized by the scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), and X-ray diffraction (XRD) to investigate the role of different raw materials in the diffusion mechanism.