External stress switching water corrosion behavior of SiC

Abstract

As the promising thermal material for the hot-end components of the next-generation advanced gas turbine engines, the operation of SiC is threatened by high-temperature water corrosion accompanied by external stress. By using reactive molecular dynamics, the influence of external stress on the high-temperature water corrosion behavior of SiC material was investigated in this study. It was found that the water corrosion behaviors of SiC at 1000 K and 2000 K were quite different: At 1000 K, SiC slabs under tensile stress exhibited more severe corrosion, as evidenced by a greater number of atoms lost. In contrast, at 2000 K, the volatilization of Si–O–Si group diminished with the increase in external stress, resulting in a reduced loss of silicon atoms. Moreover, the atomic insights indicated that the greater number of bond bridges between the Si–O–Si group and tensile SiC slab led to the more stable existence of the Si–O–Si group as well as less loss of silicon atoms. This study not only could help to understand the influence of the slab stress on the high-temperature water corrosion of SiC materials but also contribute to the design of SiC hot end components.