The ultrasonic and image analysis method for non-destructive quantification of the thermal shock damage in refractory specimens

In the present work, Mg-exchanged zeolit and silicon carbide were used as starting materials for obtaining cordierite/SiC composite ceramics with weight ratio 50:50. Samples were exposed to the water quench test from 950 degrees C, applying various number of thermal cycles (shocks). Level of surface deterioration before and during quenching was monitored by image analysis. Ultrasonic measurements were used as non-destructive quantification of thermal shock damage in refractory specimens. When refractory samples are subjected to the rapid temperature changes crack nucleation and propagation occurs resulting in loss of strength and materials degradation. The formation of cracks decreases the density and elastic properties of material. Therefore measuring these properties can directly monitor the development of thermal shock damage level. Dynamic Young modulus of elasticity and strength degradation were calculated using measured values of ultrasonic velocities obtained by ultrasonic measurements. Level of degradation of the samples was monitored using Image Pro Plus program for image analysis. The capability of non-destructive test methods such are: ultrasonic velocity technique and image analysis for simple, and reliable non-destructive methods of characterization were presented in this paper. (C) 2008 Elsevier Ltd. All rights reserved