High alloyed stainless steels and Nickel alloys are frequently used in the seawater
environment. Depending on the actual exposure conditions – temperature and residual
chlorine level – the alloys will be immune or suffer corrosion. Field experiences indicate that
while high alloyed stainless steels suffer from crevice or pitting corrosion when critical values
are exceeded, Ni-alloys will suffer from uniform surface corrosion.
This paper presents results from laboratory testing of UNS S32750, UNS N06022 and UNS
N10276 in simulated seawater environments. Artificial crevices kept at fixed potentials
simulating natural seawater and chlorinated seawater at different chlorination levels, were
exposed at temperatures ranging from 200C – 800C while the anodic current was measured.
The results from the testing show that UNS S32750 will suffer from crevice corrosion, while
UNS N06022 and UNS N10276 suffer from uniform corrosion on the surface outside the
crevice. No corrosion was found in the artificial crevices even at 800 mV SCE and 800C on
UNS N06022 and UNS N10276.
Key words: UNS S32750, UNS N06022, UNS N10276, seawater, testing, crevice corrosion,
uniform corrosion