Characterization of thermal shock damage in cordierite-mullite refractory materials by non-destructive methods

Abstract

Ultrasonic pulse velocity testing and image analysis were used to predict thermal stability of refractories. Two cordierite-mullite compositions used as substrates in fast firing of porcelain white ware characterized by different microstructure morphologies and crack propagation behavior were investigated. The measurement of the ultrasonic velocity was used to asses the material degradation with increasing thermal shock cycles and specimen damage was monitored using image analysis and further results of material degradation were obtained. A brief discussion about the correlation between thermo-mechanical properties, microstructure, crack propagation behavior and thermal shock resistance is presented. Moreover, empirical models are developed to predict thermo-mechanical properties from ultrasonic velocity and surface damage measurements. Then, service life prediction models of refractory plates from measured values of ultrasonic velocities in plates in the as-received state are presented.