Strong and weak interface synergistic enhance the mechanical and microwave absorption properties of alumina

Multifaceted balance makes the design of ceramics difficult but is urgently needed. This work purposes to grow uniform edge-rich graphene (ERG) on alumina (Al₂O₃/ERG) in-situ, then constructs a discontinuous conductive, strengthening and toughening network of crosslinked ERG by mixing Al₂O₃/ERG with Al₂O₃ and sintering. Under the guarantee of the tight-bound covalent interface, ERG and doping Al₂O₃ strengthen and toughen the ceramic by synergistic effect of weak and strong interface. And doping Al₂O₃ interrupts the conductive network of ERG to improve the impedance matching and endow material with moderate electromagnetic wave (EMW) loss capacity. The optimal flexural strength and fracture toughness of the composite ceramic reach 333.04 MPa and 12.43 MPa⋅m^1/2, respectively. Meanwhile, it can absorb 80 % or more of the incident EMW in X-band with a matching thickness of 2 mm. This work takes full advantage of ERG to prepare load-bearing EMW absorbing ceramics, which expands the idea for material design.