LAUSR

Abstract ZrB2-based ceramics containing SiC and/or ZrC were prepared by hot-pressing sintering. The characteristics of different interfaces in the sintered ceramics and their relationships with chemical compositions were investigated via SEM, HRTEM, EBSD and dihedral angle analysis. Atoms at ZrB2-ZrB2 grain boundaries (GBs) preferentially arrange orderly when ZrC is introduced into ZrB2 matrix. The percentages of rounded ZrB2-ZrB2 GBs at micro-scale decrease from 68.8% in ZrB2-20SiC (number in vol%) to 31.1% in ZrB2-20ZrC. Atomic arrangement at ZrB2-ZrC interfaces satisfies unique orientation relationship that (101)ZrB2 is parallel to (110)ZrC and [010]ZrB2 is parallel to [1 1 ¯ 0]ZrC simultaneously. Interfacial energies of different interfaces were studied by dihedral angle analysis, which indicates that ZrB2-ZrC interfaces have lower interfacial energies and ZrB2-ZrB2 GBs exhibit anisotropic interfacial energies in the ceramics containing ZrC.