AVS 53rd International Symposium
    Advanced Surface Engineering Thursday Sessions
       Session SE-ThP

Paper SE-ThP8
Protective Oxide Layers on Austenitic Stainless Steels (316L and D9) in Molten Lead Service: Formation and Reformation, Structure and Dynamics

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Advanced Surface Engineering Poster Session
Presenter: A.L. Johnson, University of Nevada, Las Vegas
Authors: A.L. Johnson, University of Nevada, Las Vegas
J.W. Farley, University of Nevada, Las Vegas
D. Koury, University of Nevada, Las Vegas
B. Hostermann, University of Nevada, Las Vegas
J. Welsh, University of Nevada, Las Vegas
T. Ho, University of Nevada, Las Vegas
L. Ma, Harry Reid Center
U. Younas, University of Nevada, Las Vegas
Correspondent: Click to Email
Liquid lead based alloys are of current interest due to their use as non-moderating coolants for fast neutron systems for power generation and nuclear waste transmutation. Unfortunately liquid lead corrodes steel by dissolution of the alloy's components. This corrosion may be mitigated by the injection of low levels of oxygen in the lead to form protective oxide layers. However the initially formed oxide layer is subject to failure and must reform when damaged under operational conditions. We have been investigating the structure and composition of the oxide layers formed on steels by oxygen controlled Lead Bismuth Eutectic (LBE) using XPS, SEM/WDS, and TEM. We find that there is an initial crystalline oxide (high Cr, low Fe) that converts to a complex bilayer (magnetite over (Fe,Cr)@sub 3@O@sub 4@) when damaged. Detailed investigation of the morphology and composition of these layers indicates the relative mobility of the alloy components in the near surface region and suggests a novel mechanism for the previously observed improvement in corrosion resistance due to cold working of the surface and near surface region. We will discuss this work in the context of current work with oxide layers formed by oxide generating species (Al, Si, and Y) introduced by sputter deposition or alloying.