Thermal shock resistance and fatigue of Zircon–Mullite composite materials

Zircon–Mullite (ZrSiO4–3Al2O3·2SiO2) composites are refractory materials widely employed in many industries. Thermal shock behaviour of these materials must be considered because it is sometimes its failure mechanism. In this work both thermal shock resistance (TSR) and fatigue (TFR) of Zircon–Mullite composites with different compositions and microstructure configurations were experimentally evaluated by a non destructive measurement of the elastic modulus (E) and compared with the prediction made from the theoretical parameters (R, R‴ and RST). A typical solid brittle material behaviour was found; a simple mathematical expression facilitated the TFR analysis. Although the microstructural configurations studied differed, the experimental behaviour of this group of materials was almost equal. This fact was satisfactorily predicted by the theoretical parameters (R and R‴) showing the importance and potential of the evaluation mechanical evaluation of the ceramic material that define these two parameters. On the other hand the slight difference evaluated in the TFR was correlated with the only parameter that takes into account the fracture toughness (RST) showing that the significance of this property in a more deep characterization of the ceramic materials.