In Situ Synthesis of (Mo,Cr)Si₂ Composites by Spark Plasma Sintering

This research investigated the impact of Cr content on the properties of (Mo,Cr)Si₂ composites. Composites with CrSi₂ molar fractions ranging from 0% to 10% were fabricated using spark plasma sintering (SPS). The study undertook a systematic analysis of the surface morphology, phase composition, mechanical properties, and high-temperature oxidation resistance of the sintered samples across different compositions. Notably, the (Mo₉₅,Cr₅)Si₂ composite sintered at 1400 °C exhibited enhanced properties, including a Vickers hardness of 11.6 GPa, a fracture toughness of 4.6 MPa·m^1/2, and a flexural strength of 397 MPa. Upon oxidation at 1500 °C, the (Mo,Cr)Si₂ composites formed a protective oxide layer comprised of SiO₂ and Cr₂O₃. It was found that the generation and thickening of the protective oxide layer was promoted by the addition of moderate amounts of Cr to MoSi₂.