Erosion characterization of SiC and Ti3SiC2 on DIII-D using focused ion beam micro-trenches. (May 2019)

• Record Type: Journal Article
• Authors: Coburn, J.; Unterberg, E.; Barton, J.; Rudakov, D.; Bykov, I.; Parish, C.M.; Wilcox, R.; Lasnier, C.; Abrams, T.; Watkins, J.; Hillis, D.L.; Bourham, M.
• Is Part Of: Nuclear materials and energy. Volume 19(2019)
• Page Start: 316
• Page End: 323
• Publication Date: 2019-05
• Subjects: Nuclear energy -- Periodicals; Nuclear fuels -- Periodicals; Nuclear reactors -- Materials -- Periodicals; Radioactive substances -- Periodicals; 621.4833
• DOI: 10.1016/j.nme.2019.02.036
• Languages: English
• ISSNs: 2352-1791

Abstract

Highlights: First-time exposure of Ti3 SiC2 to a tokamak plasma, alongside high-purity SiC. Angled Ti3 SiC2 and SiC samples survived average heat fluxes of 2–10 MW/m 2 . Ti3 SiC2 and SiC eroded at 0–9 nm/s and 27–73 nm/s, respectively, over 16 s. A new micro-trench erosion measurement technique was successfully implemented. Average ion impact angle estimates were made using micro-trench impact patterns. Abstract: Plasma-facing materials in future large-scale fusion reactors must be designed to withstand high heat fluxes from extreme off-normal events such as edge localized modes and unmitigated plasma disruptions. The erosion rates of possible tungsten-alternative materials are tested under high heat flux conditions at the DIII-D National Fusion Facility. High-purity β-3C CVD silicon carbide was exposed alongside MAX phase ceramic Ti3 SiC2 to both L- and H-mode plasma discharges in the DIII-D divertor. Samples survived average heat fluxes ranging from 2–10 MW/m 2 over 16 s. A new micro-trench erosion measurement technique was successfully implemented and measured Ti3 SiC2 and SiC erosion rates of 0–9 nm/s and 27–73 nm/s, respectively. Additionally, average ion impact angle estimates for an incident B-field angle of ∼1.5° from surface parallel were made using micro-trench impact patterns. Measurements ranged from θ = 24º–34º with respect to Bt and ϕ = 51.5º–55º below the surface normal.