Shadow corrosion
Source abstract
Abstract
An electrochemical mechanism, based on energetically favored complimentary reduction and oxidation reactions, operating in conjunction with radiolysis is proposed for explaining the shadow corrosion phenomenon observed under BWR conditions. The electrochemical reaction on platinum and nickel alloys (Inconel and X-750) is the oxidation of H 2O 2 to produce a localized enhancement in the concentrations of HO 2 and O 2 . Energy level of the conduction band of ZrO 2 matches well with that for the reduction of HO 2 and O 2 regenerating H 2O 2 . This reduction of the powerful oxidants, stimulates electron emission in ZrO 2 which then is balanced by increased oxidation of zirconium to generate additional electrons and hence also anion vacancies. A coupling between Zircaloy and platinum or nickel alloy is provided by H + transport, the source for initiating shadow corrosion, to Zircaloy-2 (Zircaloy-2 negative relative to platinum or the nickel alloy) in the gap between the materials. An enhanced localized corrosion of Zircaloy-2 occurs, its incidence dependent upon the transport of HO 2, O 2, H + and H 2O 2 in the coolant in the gap.
Source: expertdata · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Electron and X-Ray Spectroscopy Techniques · Hydrogen embrittlement and corrosion behaviors in metals · Nuclear Materials and Properties
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (11)
Show source-provided references
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