The thermal shock resistance of the ZrB2-SiC-ZrC ceramic

In the present work, the thermal shock resistance of the ZrB2-SiC-ZrC ceramic was estimated by the water quenching method and the flexural strength of the quenched specimen was measured. The measured critical temperature difference of the ZrB2-SiC-ZrC ceramic was significantly greater than that of the ZrB2-15 vol.% SiC ceramic. The improvement in thermal shock resistance was attributed to its higher fracture toughness (6.7 MPa m(1/2)) and lower flexural strength (526 MPa) relative to the ZrB2-15 vol.% SiC ceramic (4.1 MPa m(1/2) and 795 MPa) based on Griffith fracture criterion. Furthermore, the temperature and thermal stress distributions in the specimen during instantaneous water quenching were simulated by Finite element analysis. (C) 2011 Elsevier Ltd. All rights reserved.