Hydrothermal Corrosion of SiC Coupons Suppressed by Magnetron Sputtered Cr Coatings

Abstract

SiC-based components are sometimes susceptible to aqueous dissolution in LWR coolant environments. To address this issue, ~10 μm thick Cr coatings was deposited on reaction-bonded silicon carbide (RBSC) plates by magnetron sputtering. Corrosion behavior of Cr-coated SiC and -uncoated SiC coupons was studied by immersing in autoclave (345°C and 16.5 MPa). The weight loss of the Cr coated SiC coupons (3.02% after the 93-days) in the autoclave tests was effectively reduced due to their Cr-coated surfaces, in contrast to the uncoated ones (20.4% after the 78-days). Moreover, microstructural and compositional evolutions were examined by using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy. It was revealed that a continuous and dense Cr2O3 layer formed on the surface after the hydrothermal corrosion, which can suppress the in-diffusion of corrosive medium.

Green to deep-red emissive carbon dot formation by C+ ion implantation on nitrogen beam created self-masked nano-template

“…Inset of figure 7(a) shows a wide range Raman spectra for the C-ions implanted (fluence 1 × 10 17 ions cm −2 ) template where the presence of SiC is observed in addition to the G and D bands of carbon. Here, the peaks at 790 cm −1 and 965 cm −1 [34,35] are associated with the polytype 3C-SiC phase. It is observed that the peak height of SiC is comparatively higher than the peak of CD, but the area under the peak of SiC is less than CD's peak.…”