Mechanical properties and oxidation behaviors of iron-based composites with Mo-coated MoS2 powders according to elevated temperatures

Iron-based composites exhibit significant application potential in engine and aerospace fields due to their excellent comprehensive properties. In this work, elevated temperature oxidation and tensile tests were systematically explored the effects of two different methods for incorporating MoS2 powder - direct blending and utilizing Mo-coated MoS2 powders - on the microstructure, elevated temperature oxidation behavior, and mechanical properties of iron-based composites. The results reveal that composites using Mo-coated MoS2 powders demonstrate superior performance, evidenced by the lowest oxidation rate constant and the highest tensile strength at elevated temperatures among all materials tested. The lowest oxidation rate constant k and tensile strength are 0.0014 mg2 cm−4·min−1 and 241 MPa, respectively. The markedly enhanced oxidation resistance is attributed to the development of a stable passivation layer composed of FeMoO4 and Fe2O3, which effectively prevents the inward diffusion of oxygen. Additionally, the Mo coating significantly improves the interfacial bonding between MoS2 and the matrix, curbing the premature decomposition of MoS2 and contributing to microstructural stabilization, thereby enhancing mechanical strength. This research presents an effective strategy for designing high-performance iron-based composites suited for oxidative and elevated temperature service environments.