Achieving excellent mechanical and antioxidant properties in MoAlB ceramics through spark plasma sintering-high-frequency (SPS-HF) sintering

Abstract

A fully dense MoAlB ceramic was synthesized utilizing MoAlB powder through SPS-HF technology. The Vickers hardness, fracture toughness and bending strength of the MoAlB ceramic reached 14.08 GPa, 6.70 MPa m1/2 and 407 MPa, respectively. The electrical conductivity and thermal conductivity of the MoAlB ceramic at room temperature were measured to be 3.20 × 106 S m−1 and 23.50 W m−1 K−1, respectively. The ceramic exhibited excellent high-temperature oxidation resistance at 800–1200 °C for up to 64 h. Even after 64 h of oxidation at 800 °C and 1000 °C, the thickness of the oxide layer was only 2.09 µm and 2.20 µm, respectively. The oxidation behavior was controlled by a diffusion process. The rapid formation of a continuous and dense Al2O3 oxide layer effectively inhibited the inward diffusion of oxygen and the oxide layer is well bonded to the matrix.