Characterizing Oxygen Reduction Catalysis on Stainless Steel Oxides
Technical Report,01 Oct 2018,30 Sep 2019
NAVAL RESEARCH LAB WASHINGTON DC WASHINGTON United States
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In this report the characterization and electrochemical behavior of a Navy-relevant stainless steel alloy is summarized. A UNS S13800 stainless steel alloy was compared to a model binary alloy FeCr 8020 wt percent , as well as its constituent pure components, in order to determine the relevant catalytic species for the oxygen reduction reaction. The oxygen reduction reaction is an important reaction in galvanic corrosion. Electrochemical and surface analytical techniques gave insight into the role of the oxide composition on the electrochemical properties. It was found that enrichment of chromium occurs near the surface, but both iron and chromium species are present on the outer surface oxide layer. The iron affected the impedance characteristic of the more insulating chromium oxide layer. There was a coincident increase in the capacitance of the passive film and oxidation state change of the iron species where the stainless steel alloy becomes active for the oxygen reduction reaction. These studies suggest that the oxidation state of the iron determines the oxygen reduction reaction behavior of a stainless steel. Understanding the relationship between the stainless steel alloy composition and the oxygen reduction reaction behavior is important for the development of a broad model for the electrochemical behavior of stainless steels in galvanic corrosion systems.
- Organic Chemistry
- Inorganic Chemistry
- Metallurgy and Metallography