The role of He irradiation in the corrosion behaviour of T91 in high-temperature steam

Abstract The role of He irradiation in the corrosion behaviour of T91 ferritic/martensitic steel in high-temperature steam was investigated. Although irradiation did not modify the duplex character of the oxide or its structure, the microstructure and thickness of the oxide layer were severely affected by the irradiation, which induced the formation of a more porous and thicker oxide. He irradiation contributed to the rate-limiting step (internal diffusion of oxygen) of oxidation by making the oxide more porous and consequently creating more diffusion pathways and available growing space, which increased the oxidation rate of T91 as the irradiation dose was increased.