Title

The Corrosion of Alloy 718 During 800 Mev Proton Irradiation

Document Type

Article

Publication Date

Spring 2000

Abstract

The real-time polarization resistance of Alloy 718 during high energy proton irradiation (measured with electrochemical impedance spectroscopy) decreased from 1.7×103 ohm m2 in the absence of irradiation to 8.2 ohm m2 at a proton beam current of 0.4 mA. Because the proton beam spot size was smaller than the sample (that is, proton flux decreased radially from the beam center), two methods for determing corrosion rate from polarization resistance were employed. The first method assumed that the distribution of corrosion was uniform across the entire probe surface. With this assumption, the corrosion rate was found to vary from 0.041 μm/yr at an average proton current of 0.001 mA–3.1 μm/yr at an average proton current of 0.40 mA. The second method used proton flux as a criterion for determining the area of highest damage. At a peak proton flux of 1.77×1018 p/m2 s, calculated at an average proton current of 0.40 mA, the corrosion rate was 60.9 μm/yr. These results are discussed within the context of water radiolysis and direct 718/proton interactions.

Volume

277

Issue

3

First Page

250

Last Page

262

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