Several candidate container materials have been studied in modified Yucca Mountain (YM) ground water in the presence or absence of YM bacteria. YM bacteria increased corrosion rates by 5-6 fold in UNS G10200 carbon steel, and nearly 100-fold in UNS N04400 Ni-Cu alloy. YM bacteria caused microbiologically influenced corrosion (MIC) through de-alloying or Ni-depletion of Ni-Cu alloy as evidenced by scanning electronic microscopy (SEM) and inductively coupled plasma spectroscopy (ICP) analysis. MIC rates of more corrosion-resistant alloys such as UNS N06022 Ni-Cr-Mo-W alloy, UNS N06625 Ni-Cr-Mo alloy, and UNS S30430 stainless steel were measured below 0.05 μm/yr, however YM bacteria affected depletion of Cr and Fe relative to Ni in these materials. The chemical change on the metal surface caused by depletion was characterized in anodic polarization behavior. The anodic polarization behavior of depleted Ni-based alloys was similar to that of pure Ni.

Subject
Water, Materials, Corrosion rate, Metal surfaces, Nickel chromium molybdenum alloys, Containment, Dissolution, Anode surfaces, Bacteria, Copper nickel alloys, Corrosion coupons, Anodic polarization, Microbiologically influenced corrosion
Keywords:
MIC, container materials, YM bacteria, de-alloying, Ni-depletion, Cr-depletion, polarization resistance, anodic polarization
Government work published by the Association for Materials Protection and Performance (AMPP) with permission of the author(s). Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
1999
GOV
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