Synthesis and characterization of ternary layered i‐MAX (Mo2/3Y1/3)2AlC ceramics fabricated by spark plasma sintering

Abstract

AbstractIn this paper, the i‐MAX phase (Mo2/3Y1/3)2AlC ceramic with high purity of 98.29 wt% (1.13 wt% Y2O3 and 0.58 wt% Mo2C) and high relative density of 98.59% was successfully synthesized by spark plasma sintering (SPS) at 1500°C with the molar ratio of n(Mo):n(Y):n(Al):n(C) = 4:2:3.3:2.7. The positions of C atoms in the crystal of (Mo2/3Y1/3)2AlC were determined. Microstructure and physical and mechanical properties of (Mo2/3Y1/3)2AlC ceramic were systematically investigated. It was found that the obtained (Mo2/3Y1/3)2AlC ceramic had an average grain size of 32.1 ± 3.1 μm in length and 14.2 ± 1.7 μm in width. In terms of physical properties, the measured thermal expansion coefficient (TEC) of (Mo2/3Y1/3)2AlC was 8.99 × 10−6 K−1, and the thermal capacity and thermal conductivity at room temperature were 0.43 J·g−1·K−1 and 13.75 W·m−1·K−1, respectively. The room temperature electrical conductivity of (Mo2/3Y1/3)2AlC ceramic was measured to be 1.25 × 106 Ω−1·m−1. In terms of mechanical properties, Vickers hardness under 10 N load was measured as 10.54 ± 0.29 GPa, while flexural strength, fracture toughness, and compressive strength were determined as 260.08 ± 14.18 MPa, 4.51 ± 0.70 MPa·m1/2, and 855 ± 62 MPa, respectively, indicating the promising structural applications.