PNNL

Abstract

The use of SiC composites in fusion environments is predicated on stability under neutron irradiation, on outstanding high-temperature mechanical properties, and on chemical inertness and corrosion resistance. However, SiC is susceptible to many forms of corrosion in water and in water vapor where silica formation is required as a protective layer because silica forms stable hydroxides that are volatile, even at low temperatures. SiC composites have an additional concern that fine-grained fibers and weak interfaces provide the required fracture toughness, but these components may also exhibit susceptibility to corrosion that can compromise material properties. In this work we examine and review the compatibility of fibers and interfaces, as well as the SiC matrix, in proposed fusion environments including first wall, tritium breeding, and blanket modules and module coolants.