Preparation of high-entropy nitride ceramics (TiVCrNbZr1-x)Ny by introducing nitrogen vacancies

ABSTRACTHigh-entropy ceramics have emerged as a research hotspot in the field of ceramics due to their single-crystal structure and excellent physicochemical properties. In this paper, an innovative approach is adopted to synthesize high-entropy nitride ceramics (TiVCrNbZr1-x)Ny. To achieve this, the non-stoichiometric compound TiN0.3 was introduced as a sintering additive and the Spark Plasma Sintering (SPS) technique was employed. By adding TiN0.3, successfully preparing high-entropy nitride ceramics at 1500°C, which introduces vacancy defects that provide additional space for the diffusion and migration of atoms, allowing for more efficient migration and diffusion within the crystal structure, thereby accelerating the sintering process. The (TiVCrNbZr1-x)Ny- xZrO2 samples achieved outstanding mechanical properties when sintered at 1700°C, owing to the mechanisms of solid solution strengthening and second-phase diffusion toughening. Specifically, the samples exhibited a hardness of 25.42 ± 1.58 GPa, a flexural strength of 888 ± 32 MPa, and a fracture toughness of 6.23 ± 0.27 MPa·m1/2. This innovative sintering route provides an efficient method for preparing high-entropy nitride ceramics at relatively low temperatures without sacrificing quality. This approach not only enhances production efficiency but also expands the potential practical applications of these ceramics.