Characterization of Corrosion Behavior of Irradiated X65 Low Carbon Steel in Aerobic and Unsaturated Gaomiaozi Bentonite

摘要

2.98 kGy/h(1007 h) gamma irradiation and 90 ℃(2000 h) thermal aging were exerted to X65 grade low carbon steel buried in Gaomiaozi bentonite containing 17 wt% Beishan groundwater. The average corrosion rate of X65 low carbon steel was measured. The elemental and phase distribution on cross section was characterized by using electron probe micro-analysis, high-resolution X-ray diffraction, and micro-X-ray diffraction. The following conclusions can be made: the average aerobic corrosion rate of the carbon steel is(45.16 ± 1.53) μm/year. Taking the original surface as boundary, the corrosion scale is divided into an internal dense product layer(DPL) mainly composed of Fe_3O_4 with segregated FeCO_3 at the corrosion front and an external DPL mainly composed of Fe_3O_4 with segregated α-Fe_2O_3 and bentonite at some relics.Si, S, and Cl are concentrated at the corrosion front of the internal DPL, while Si and Al are concentrated at the external DPL.