Connection Between Atomic Scale Characterization and Electrochemical Behavior during Passivation of Single Crystals on Ni-Cr and Ni-Cr-Mo Alloys
Abstract
Ni-Cr and Ni-Cr-Mo alloys owe their outstanding corrosion resistance to the surface enrichment of passivating Cr(III) oxides and synergistic effect of Cr and Mo in case of Mo-containing alloys [1-3]. However, the specific roles of minor elements are not well understood especially with respect to precise location of Mo relative to the oxide/metal interface, nor the atomistic processes responsible for protective-oxide layer growth and breakdown. The composition, structure and thickness of the passivating oxide films are challenging to characterize considering their nanoscale dimensions and the high electric field imposed during growth in solution. Key processes that take place within the oxide and regulate passivation are controlled by defect interactions that are atomic, ionic, and electronic in nature and currently poorly understood, often needed to be studied at the resolution and detection limits of experimental methods [4]. Common electrochemical methods such as AC and DC electrochemistry are rarely connected with atomic scale ex situ techniques such as scanning tunneling (STM), atomic force (AFM) and transmission electron (TEM) microscopies to yield crucial information on structure, molecular and electronic properties of the oxides [5]. The main goal of this work is to integrate single crystal electrochemical measurements with nanoscale characterization to advance fundamental understanding and eventually predict the roles of Cr and Mo on surface stability in corrosive environments. Such a connection between global electrochemistry and atomic studies is infrequently reported [6].
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 01, 2016
- Source ID
- 10.1149/ma2016-02/10/1144
Entities
People
- Ahmet Gulec
- Evan Zeitchick
- Gopalakrishnan Ramalingam
- John Pereezko
- John R. Scully
- Kateryna Gusieva
- Katie Lutton
- Laurence D. Marks
- Petra Reinke
- Xiao-xiang Yu