Assessing erosion and retention of silicon carbide based materials in DIII-D divertor^*

A series of experiments performed on DIII-D have exposed SiC based materials to a variety of plasma conditions using the DiMES apparatus in order to better characterize local gross erosion and hydrogenic retention. Our most recent results suggest that SiC is less susceptible to chemical sputtering as compared to graphite and is not solely due to the stoichiometric reduction in carbon. Furthermore, within the silicon physical sputtering regime, inclusion of silicon surface enrichment of SiC is necessary to account for differences between predictions and experiments. An extended effort to characterize the hydrogen retention of exposed samples and the influence of SiC microstructure are obtained using TDS, NRA, and LIMS-LIBS along with SEM and EBSD, as this is historically, a primary concern with SiC. The combination of techniques enables association of grain boundaries and orientation with aerial and depth profiles of deuterium implanted during DIII-D experiments. These results provide a needed dataset for SiC and further motivate in identifying plasma-facing materials that exhibit limited erosion and chemical reactivity but are thermally conductive, thermomechanically tough, and low-Z by nature.