Laminated ZrB2–SiC/graphite ceramics with simultaneously improved flexural strength and fracture toughness

Layered graphite was introduced into ZrB2–SiC ceramics to prepare laminated composite by tape casting and hot pressing. Both fracture toughness and flexural strength were improved in the laminates, reaching the peak values of 12.4 MPa m1/2 and 580 MPa, respectively. Cracks propagated in a step-like mode resulting from the layered, soft interface layer, so crack branch and interface delamination were considered as the main toughening mechanisms. The compressive stress in the ZrB2–20 vol% SiC layer was the main strengthening mechanism.