NICOP - Ion Transport in Growing Oxide Layers on Cr-containing Alloys
Abstract
Surface oxides is a topic of central importance since nearly all engineering alloys are oxidized intheir environment and their oxidation behavior is a key for their performance and durability.Oxide growth on metals is governed by the transfer of species at the metal/oxide andoxide/environment interfaces and in the oxide and it is recognized to play a fundamental role inthe mechanisms of passivation, dissolution and localized corrosion events.The objective of the present research program will be to acquire the knowledge of the nature(anions or cations) of the vacancies that are transported and limit the growth of the oxide and todetermine their diffusion coefficient using a novel direct in situ method based on two-stepoxidation experiments performed with 16O- and 18O-labelled oxidants and analysis by Time-of-Flight Secondary Ion Mass Spectrometry.The work, performed by the Physical Chemistry of Surfaces Research Group (PCS Group) atIRCP CNRS-Chimie ParisTech, will be applied to model systems in order to gain new insightinto the mechanisms of early stage oxidation and aqueous corrosion, an objective shared with theMURI project funded by the ONR and entitled ???Understanding corrosion in 4D???.Thermal and electrochemical oxidation of the same material, binary NiCr alloys, will be studiedby the PCS group thus defining a unified approach which will allow comparison of data obtainedon the same system in gas phase or aqueous solution with the novel direct in situ method, andfrom which a better understanding and a more general model can be derived.The data that will be obtained are related to key factors for the growth and stability of surfaceoxide layers: nature of defects, growth controlling parameters, semiconductor properties, andspecific sites for possible interaction with chlorides.The work will benefit to the ONR by contributing significantly to the understanding of earlystage oxidation, which is the aim of the MURI project, by bringing additional data on an aspectnot covered by the MURI project, and using a novel methodology not developed in the MURIteam.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 19, 2018
- Source ID
- N629091812172
Entities
People
- Philippe Marcus
Organizations
- National Center for Scientific Research
- Office of Naval Research
- United States Navy