Open AccessLOCALISED CORROSION OF STAINLESS STEELS 316L AND 2205 IN SYNTHETIC BENTONITE PORE WATER AND BENTONITE SLURRY
Author(s) -
J. Stoulil,
Людмила Васильевна Павлова,
Milan Kouřil
Publication year - 2021
Publication title -
acta metallurgica slovaca
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.277
H-Index - 13
eISSN - 1338-1156
pISSN - 1335-1532
DOI - 10.36547/ams.25.1.4
Subject(s) - bentonite , slurry , corrosion , materials science , metallurgy , stress corrosion cracking , ultimate tensile strength , cracking , composite material , geotechnical engineering , geology
One concept for Czech canister construction for deep geological repository considers stainless steel as an inner case material. Corrosion resistance to localised (pitting/crevice) corrosion and stress corrosion cracking of austenitic stainless steel 316L and duplex steel 2205 was studied. The environment was synthetic bentonite pore water (SBPOW) of domestic bentonite BaM, or a slurry of bentonite in SBPOW. Tests were carried out between 40 °C and 90 °C under anaerobic conditions of a nitrogen atmosphere. The following methods were used for evaluation: potentiostatic tests at oxidation-reduction potential of the environment, long-term exposure tests in SBPOW and slurry, slow strain rate tensile test (SSRT), exposure test of U-bends, and optical microscopy. Results showed no susceptibility of either material to stress corrosion cracking. No localised corrosion was observed up to 70 °C. There was no localised attack observed in SBPOW at 90 °C, but there was localised corrosion detected in the bentonite slurry. Forced breakdown of the passive layer during SSRT, and artificial crevices (O-rings), showed no effect on localised corrosion propagation. The detrimental effect was probably a result of the adsorption ability of the bentonite particles, which allowed breakdown of passive layer and disabled repassivation of metastable pits.