Dissolution corrosion of 4H‐SiC in lead‐bismuth eutectic at 550°C

Abstract

The corrosion behavior of 4H-SiC in lead-bismuth (Pb-Bi) eutectic (LBE) at 550°C is investigated. To clarify the effect of irradiation damage on corrosion, samples with and without Si 5+ ion irradiation are contrastively evaluated. The main results show that dissolution corrosion occurs in both unirradiated and irradiated samples, while the irradiation damage can accelerate the corrosion rate. The corroded surface is characterized by the loss of C element and the formation of amorphous layers with a slight enrichment of Si atoms. The possible reasons are discussed. K E Y W O R D S corrosion, microstructure, nuclear materials, radiation damage, SiC

Environmental degradation of structural materials in liquid lead- and lead-bismuth eutectic-cooled reactors

“…Similar results were also reported by Lillard et al [270] and Yao et al [271]. In addition to enhanced oxidation, Li et al [272] reported that 4H-SiC was subjected to enhanced dissolution corrosion in oxygen-saturated LBE at 550 • C for 167 h of exposure, after irradiation up to 1.6 dpa at RT with 880 keV Si 5+ ions.…”

Fast‐flowing LBE corrosion of the SiC pump impeller: Numerical and experimental investigations

“…Takahashi 13 F I G U R E 1 4 Results of the SEM-energy dispersive spectrometer (EDS) line scan of cross-section of the SiC impeller after corrosion reported that the weight loss of the SiC specimen was 13.2 g/m 2 during his corrosion test, and the corrosion mechanism could be described by the following reaction equation, SiC + 2PbO → SiO 2 + 2Pb + C. Moreover, a cracked layer appeared on the SiC specimen, which was due to the shear and normal stress of the fast-flowing LBE. 25 Besides, Li 14 pointed out that the LBE corrosion of SiC was characterized by the formation of an amorphous layer on the corroded surface, which was caused by the loss of C element and the enrichment of Si element. Lei 15 confirmed that element C wa dissolved more easily than element Si on SiC surface in LBE, and the depletion of C might lead to the formation of a layer of amorphous Si.…”

“…SiC ceramic was regarded as a candidate of the cooling pump impellers of accelerator-driven systems and Gen-IV lead-cooled fast reactors [1][2][3] due to its many excellent properties such as irradiation resistance, corrosion resistance, high-temperature strength, high-temperature creep resistance, oxidation resistance, and neutron transparency. [4][5][6][7][8][9] Although some scholars studied the compatibility of SiC bulk ceramics with LBE, 1,[10][11][12][13][14][15] there were no reports on the dynamic corrosion behavior of SiC impellers in the liquid lead-bismuth eutectic (LBE) alloy.…”

“…Takahashi et al 13 investigated the corrosion characteristics of SiC ceramics in flowing LBE with the conditions of 550 • C, 1 m/s, 10 −6 wt.% oxygen, and 2000 h. He found that SiC exhibited good resistance against oxidation and element dissolution, and the weight loss of SiC was lower than those of steel specimens exposed to the same test condition. Li et al 14 used scanning electron microscopy (SEM), Raman, TEM, and AFM to characterize the LBE corrosion of the irradiated SiC at the test conditions of 550 • C, saturated oxygen and 167 h. Li pointed out that irradiation accelerated the corrosion rate due to the loss of C and the enrichment of Si accompanied by the formation of an amorphous layer. Lei et al 15 investigated the dissolution corrosion of LBE on 4 H-SiC (0001) surfaces based on first-principle calculation and experiment research.…”