Toughening and reinforcing zirconia ceramics by introducing boron nitride nanotubes

Boron nitride nanotube (BNNT)-toughened ZrO2 ceramics were fabricated by hot-press sintering. Compared with monolithic ZrO2 ceramic, the addition of 1.0 wt% BNNT could result in an increase of flexural strength from 895.5 MPa to 1143.3 MPa and fracture toughness from 7.94 MPa m1/2 to 13.13 MPa m1/2. The incorporation of BNNTs could not only strengthen grain boundaries but boost BNNT-induced phase transformation. The breakage of BNNTs could also dissipate some fracture energy, giving rise to the enhanced mechanical properties.