Enhanced mechanical properties of SPS sintered h–BN based ceramics with Al3BC3 addition

Abstract

A novel h–BN based ceramics, fabricated through spark plasma sintering, was developed by incorporating varying Al3BC3 additives. At high temperatures, Al3BC3 reacted with h–BN, resulting in the in–situ formation of AlN, B4C, and C. AlN acted as the primary reinforcement distributed along the grain boundaries of h–BN, creating a structural framework that filled internal pores and improved material density. DFT calculations highlighted favorable bonding at the interfaces between h–BN (100) and AlN (100) surfaces, and this robust bonding contributed to further enhancing their thermodynamic stability and mechanical properties. Upon reaching the Al3BC3 addition of 30 wt%, the h–BN–based composite ceramics exhibited optimal comprehensive performance, and the corresponding relative density, flexural strength, fracture toughness, and vickers hardness reached values of 96.86 %, 229.36 ± 2.14 MPa, 2.81 ± 0.03 MPa·m1/2, and 175.87 ± 8.81 kg·mm−2 respectively.