Bionic structural design and model calculation for high toughness Si3N4f/BNi fibrous monolithic ceramic: A strategy from the fibrous cell and interface

Preeminent mechanical and dielectric performances are demonstrated by covalently bonded Si 3 N 4 ceramics, yet their application range is still challenged because of limited toughness and sintering density. In this work, the Si 3 N 4 f /BN i fibrous monolithic ceramic with uniaxially arranged Si 3 N 4 fibers cells separated by BN interfaces were successfully synthesized via hot-pressed sintering based on bionic structural design. The Si 3 N 4 f /BN i fibrous monolithic ceramics with bionic structure exhibited flexural strength, fracture toughness, and density of up to 501 MPa, 10.99 MPa m 1/2 , and 3.43 g/cm 3 , respectively. The results revealed that bionic structural design enables to significantly increase the toughness of the ceramic without sacrificing its strength. Furthermore, an original model for determining the flexural strength of fibrous monolithic ceramics was proposed, which can account for various shapes of fibrous cells. The findings of this research open up new prospects for achieving competitive mechanical performance of ceramics.