Unusual corrosion behavior of 1.4542 exposed a laboratory saline aquifer water CCS-environment

Differently heat treated coupons of 1.4542 were kept at T=60 degrees C and ambient pressure as well as p=100 bar for 700 h - 8000 h in an a) water saturated supercritical CO2 and b) CO2-saturated synthetic aquifer environment similar to on-shore CCS-sites in the Northern German Basin. Surface corrosion layers are homogeneous but unusually discontinuously ellipsoidal. After 8000 h at 100 bar maximum corrosion rate in the liquid phase is approximately 0.014 mm/year, with normalizing providing best corrosion resistance and approximately 0.003 mm/year in the supercritical phase where hardening+tempering at 670 degrees C leads to lowest corrosion rates. (C) 2017 The Authors. Published by Elsevier Ltd.