Amorphous Coating for Protection of Austentic Steel in Coal-Fired Environments

65417 More efficient fusion energy systems will require low-activation-based advanced structural materials for the first wall reactor in order to sustain high radioactive doses and stresses at elevated temperatures. SiC-based fiber reinforced composites are attractive, but these composites can only be produced in limited sizes and shapes. Therefore, a suitable joining technology must be developed. Unfortunately, current joining methods lack microstructural control at the join interface, preventing the fabrication of strong and durable joints that are reliable under operational conditions. This project will develop a reactive joining approach, in which the mating surfaces are pretreated to obtain a carbon-rich surface that subsequently reacts with a silicon-rich interlayer to yield a contiguous microstructure across both the joint and the mating parts. Phase I will demonstrate feasibility by pretreating monolithic SiC pieces to obtain the carbon-rich porous surface. The reaction kinetics of the pretreatment step will be controlled to yield the desirable microstructure. The pretreated surfaces will then be used to produce the joint using silicon as the interlayer. Commercial Applications and Other Benefits as described by the awardee: Joining of SiC is a critical enabling technology for use of SiC components in a broad range of applications including fusion systems, heat exchangers, combustors, and components used in space and aerospace systems. The technology may also be suitable for the brazing of SiC with metals, important for automotive and other energy-based material systems.