Fiscal Year 2004 Summary Report: General Corrosion and Passive Film Stability

Orme, C A ; Gray, J ; Hayes, J ; Wong, L ; Rebak, R ; Carroll, S ; Harper, J ; Gdowski, G

Lawrence Livermore National Laboratory

关键词: Corrosion;    Dusts;    Alloys;    Evaporation;    36 Materials Science;   

DOI  :  10.2172/15015182
RP-ID  :  UCRL-TR-208588
RP-ID  :  W-7405-ENG-48
RP-ID  :  15015182

美国|英语

来源: UNT Digital Library

【 摘 要 】

This report summarizes both general corrosion Alloy 22 from 60 to 220 C and the stability of the passive film from 60 to 90 C over a range of solution compositions that are relevant to the in in-drift chemical environment at the waste package surface. The general corrosion rates were determined by weightloss measurements in a range of complex solutions representing the evaporation of seepage water and more concentrated brines representing brines formed by the deliquescence of dust deposited on the canisters. These data represent the first weightloss measurements performed by the program at temperatures above 90 C. The low corrosion rates of Alloy 22 are attributed to the protective oxide film that forms at the metal surface. In this report, changes in the oxide composition are correlated with weightloss at the higher temperatures (140 related 140-220 C) where film characterization had not been previously performed. The stability of the oxide film was further analyzed by conducted a series of electrochemical tests in progressively more aggressive acid solutions to measure the general corrosion rates in solutions that mimic crevice or pit environments.