Buzz-o-sonic was used to assess the thermal stress damage of Si-O-C micro-composite foams derived from a preceramic polymer1. This work was performed at the Department of Materials Science, Glass and Ceramics, the University of Erlangen-Nuremberg, Germany

The thermal stress damage resistance was measured after preheating the specimens in a furnace at 1130 °C and 1430 °C for 10 minutes. The specimens were taken out of the furnace and quenched in water of room temperature (25 °C). The specimens were stirred in water until they cooled completely. The bending strength sigma n after n cycles was tested in a four point bending setup with a crosshead speed of 0.5 mm/min. The Young's modulus En was measured by impulse excitation (ENV 843-2) using the Buzz-o-sonic testing system. n was 1 for dt=1400 °C and n dt=1, 2, 5 and 10 for = 1100 °C, respectively. Damage parameters Dsigma and DE were calculated according to equation 1:

eq1.......................................1

The results are shown below

E vs T 1 Juergen Zeschky, Thomas Hoefner, Henning Dannheim, Michael Scheffler and Peter Greil, "High Temperature Behaviour of Ceramic Foams from Si/SiC-Filled Preceramic Polymers," presented at the 28 th International Cocoa Beach Conference and Exposition on Advanced Ceramics & Composites (2004)