Effects of Y2O3 on SiC/MoSi2 composite by mechanical-assistant combustion synthesis

MoSi2 based materials are considered as a potential high temperature structural parts. In this work, a 0.5 wt% Y2O3–20 vol% SiC/MoSi2 composite was successfully prepared by pressureless sintering from mechanical-assistant combustion synthesized powders. Adding a small amount of Y2O3 to the SiC/MoSi2 composite decreased the apparent activation energy of sintering by 10.4%, resulting in a denser composite with finer grains. The relative density, flexural strength, Vickers hardness and fracture toughness of 0.5 wt% Y2O3–20 vol% SiC/MoSi2 increased by 5.3%, 27.7%, 27.2% and 35.8% as compared to 20 vol% SiC/MoSi2, respectively. The oxidation mass gain of Y2O3–20 vol% SiC/MoSi2 at 1200 °C was higher than that of 20 vol% SiC/MoSi2 for 16.9%, while it still exhibited very good oxidation resistance at this temperature.

► Synthesis of Y2O3–SiC–MoSi2 by pressureless sintering from MASHSed powders
► It was obtained at lower temperature (1500 °C).
► Adding Y2O3 to SiC/MoSi2 composite decreased the apparent activation energy a lot.
► It showed fine microstructure and good mechanical properties.