The Understanding of the Microstructural Changes of Refractory Castables after Thermal Shocks through Damping Measurements
1 GHI/RWTH-Aachen, Institute of Mineral Engineering – Department of Ceramics and Refractory Materials, 52062 Aachen/Germany
2 RWTH-Aachen, Institute of Mineral Engineering – Department of Ceramics and Refractory Materials, 52062 Aachen/Germany
Revision 06.10.2011, 24.10.2011
Volume 4, Issue 1, Pages 119-124
Abstract
The work herein correlates the damping measurements and themicrostructural modifications of refractory castables after thermalshocks at air. According to DIN EN 993-11, thermal shock at air atdifferent temperatures (750, 850, 950 and 1050 °C) were progressivelyconducted on refractory samples based on tabular aluminawith addition of partially stabilized zirconia (PSZ). The same thermalshocks were carried out at 950 °C on white fused alumina samplesas well. The thermal shock damage evaluation of high-alumina refractorycastables was based on dynamic Young’s modulus anddamping characterization data obtained via the impulse excitationtechnique (IET), according to the ASTM E1876-07. Scanning ElectronMicroscopy (SEM) completes this survey so as to understand theelastic changes of these refractory formulations. The results showthat the damping increase in PSZ castables may be explained bycrack nucleation and propagation while such phenomena do notoccur in WFA castable.
Keywords
thermal shock, impulse excitation technique, partially stabilized zirconia, Young’s modulus, damping
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