Ceramics-Silikáty 52 (2) 115-119 (2008)

Thermal Shock Damage Characterization of High Temperature Ceramics by Non Destructive Test Methods

M. Posarac, M. Dimitrijevic, J. Majstorovic, T. Volkov-Husovic,  A. Devecerski, B. Matovic

In the present work a mixture of commercially available spinel, quartz (SiO₂) and alumina (Al₂O₃) corresponding to a cordierite stoichiometry was used as starting material for obtaining cordierite/SiC composite ceramics with weight ratio 30:70 and 50:50. Cordierite and silicon carbide are ceramic materials suitable for high temperature application with superior thermal stability, thermal shock resistance, low thermal expansion coefficient and good chemical resistance. The composite material could exhibit advantages of its constituents when the components have optimized properties and they are mixed in the proper ratio. Behavior of composite ceramics after thermal shock treatments was investigated. Thermal shock of the samples was measured using standard laboratory water quench test. 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. Dynamic Young modulus of elasticity and strength degradation were calculated using measured values of ultrasonic velocities obtained by ultrasonic measurements.

Keywords: Ultrasonic velocity, Refractories, Cordierite/SiC composite ceramics, Thermal shock resistance