Microstructure and mechanical properties of laminated ZrB2–SiC ceramics with ZrO2 interface layers

Laminated ZrB2–SiC ceramics with ZrO2 interface layers were successfully prepared by tape casting, laminating and hot pressing. The flexural strength and fracture toughness are 561 ± 20 MPa and 14.4 ± 0.3 MPa m1/2 for parallel direction, and 432 ± 18 MPa and 5.8 ± 0.3 MPa m1/2 for perpendicular direction. The fracture toughness for parallel direction is improved significantly compared to monolithic ZrB2–SiC ceramics. The toughening mechanism was attributed to the deflection and branch of the crack and the new microcracks, which would increase the propagation path and fracture work.

► Laminated ZrB2–SiC ceramic was firstly prepared by tape casting and hot pressing.
► The fracture toughness is 14.4 ± 0.3 MPa m1/2 in parallel direction, which is obviously increased.
► The anisotropy of laminated ceramics was firstly investigated.
► The fracture in perpendicular direction is successive fracture with crack damage tolerance.
► Toughening mechanisms are crack deflection, crack branching and ZrO2 phase transformation reinforcement.