High temperature mechanical properties of laminated ZrB2-SiC based ceramics

Two laminated ZrB2-SiC based ceramics were prepared by tape casting and subsequent hot pressing, with BN (LZB) and graphite (LZG) as interface layers. The LZB specimen presents flexural strength of 381 MPa at room temperature and 111 MPa at 1500 degrees C; while the LZG specimen shows flexural strength of 414 MPa at room temperature and 377 MPa at 1500 degrees C. In addition, the flexural strength of LZG specimen is always higher than that of the LZB specimen in the temperature range from room temperature to 1500 degrees C. Such higher strength is attributed to the healing of surface microcracks and pores by the SiO2 glass phase, producing less glass phase in graphite interface layers at high temperature. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.