Influence of moisture absorption on the synthesis and properties of Y2O3–MgO nanocomposites

Abstract Y2O3–MgO nanocomposites are appropriate materials for hypersonic infrared windows and domes because of their low emissivity and improved mechanical properties. In this study, the synthesized Y2O3–MgO nanopowders are investigated to evaluate the influence of moisture absorption on the manufacturing process and properties of the resulting nanocomposites. It is shown that MgO plays a more significant role than Y2O3 in the moisture absorption of the composite nanopowders, and the absorbed moisture leads to a lowering IR transmittance of the final Y2O3–MgO nanocomposites. A higher calcination temperature improves the resistance to moisture absorption of Y2O3–MgO nanopowders, which is beneficial for IR transmittance of the final nanocomposites. In addition, increasing the sintering temperature to 1100 °C during spark plasma sintering (SPS) minimizes the influence of absorbed moisture on the IR transmittance of the final nanocomposites. In the water resistance test, the Y2O3–MgO nanocomposites demonstrate severely eroded surfaces and degraded IR transmittance after water erosion, suggesting the requirement for necessary water-proof treatments on such materials in practical applications.