Hierarchically laminated structures make SiC ceramics with excellent damage resistance

Bioinspired structures provide promising paths to address the inherent brittleness of structural ceramics. Here, we proposed a hierarchically laminated structure to enhance the damage tolerance and fracture toughness of SiC ceramics. The SiC ceramics were formed by tape casting with graphene platelets (GPLs) as the reinforcement, and then sintered by hot pressing and liquid silicon infiltration. Thus, hierarchically laminated architectures were constructed by the casting sheets, the directionally distributed GPLs and the in-situ β-SiC grains. With the increase of sintering aid, the bulk density of the laminated ceramics increased from 3.09 ± 0.03 g/cm 3 to 3.18 ± 0.02 g/cm 3 ascribed to infiltration of the glassy phases and the liquid silicon. Due to the hierarchically laminated structure, the flexural strength increased from 299.4 ± 4.1 MPa to 350.61 ± 9.5 MPa with the infiltration of liquid silicon, while the fracture toughness increased from 7.6 ± 0.8–10.4 ± 0.5 MPa·m 1/2 ascribed to the novel toughening mechanisms.