Preparation of MoSi2@ZrO2 core-shell powders by hydrothermal-calcination and evaluation of low-temperature oxidation resistance

MoSi 2 is a promising candidate for high-temperature, structural materials. However, their oxidation resistance is poor below 600 °C. To prevent MoSi 2 from being oxidized at low temperatures, core-shell structured MoSi 2 @ZrO 2 powder were prepared by hydrothermal-calcination approach. First, MoSi 2 @Zr(OH) 4 core-shell composite powder with nano-sized Zr(OH) 4 shell particles were synthesised using a hydrothermal method . Subsequently, the MoSi 2 @ZrO 2 core-shell structured powder were obtained by calcination of the MoSi 2 @Zr(OH) 4 powders at 900 °C for 2h. Finally, microstructure and oxidation behaviour of the MoSi 2 @ZrO 2 powder at 400 °C–600 °C in air were investigated systematically. Microstructural analysis revealed that all samples had a distinct core-shell structure, and the ZrO 2 shells coated the surface of the MoSi 2 core. Oxidation behaviour studies showed that the dense ZrO 2 shell layer could isolate the MoSi 2 surface from oxygen, improving the low-temperature oxidation resistance and providing better low-temperature antioxidant properties than those of the MoSi 2 and MoSi 2 @Zr(OH) 4 core-shell structures.