scholarly journals Real-Time Monitoring of Aluminum Crevice Corrosion and Its Inhibition by Vanadates with Multiple Beam Interferometry in a Surface Forces Apparatus

2015 ◽  
Vol 162 (7) ◽  
pp. C327-C332 ◽  
Author(s):  
Buddha Ratna Shrestha ◽  
Qingyun Hu ◽  
Theodoros Baimpos ◽  
Kai Kristiansen ◽  
Jacob N. Israelachvili ◽  
...  
Keyword(s):  
Real Time ◽  
Crevice Corrosion ◽  
Surface Forces ◽  
Surface Forces Apparatus ◽  
Real Time Monitoring ◽  
Multiple Beam ◽  
Multiple Beam Interferometry

scholarly journals In situ nano- to microscopic imaging and growth mechanism of electrochemical dissolution (e.g., corrosion) of a confined metal surface

2017 ◽  
Vol 114 (36) ◽  
pp. 9541-9546 ◽  
Author(s):  
C. Merola ◽  
H.-W. Cheng ◽  
K. Schwenzfeier ◽  
K. Kristiansen ◽  
Y.-J. Chen ◽  
...  
Keyword(s):  
Real Time ◽  
Crevice Corrosion ◽  
Inorganic Materials ◽  
General Mechanism ◽  
Surface Forces Apparatus ◽  
Metallic Surfaces ◽  
Pit Formation ◽  
Wide Range ◽  
Sudden Appearance

Reactivity in confinement is central to a wide range of applications and systems, yet it is notoriously difficult to probe reactions in confined spaces in real time. Using a modified electrochemical surface forces apparatus (EC-SFA) on confined metallic surfaces, we observe in situ nano- to microscale dissolution and pit formation (qualitatively similar to previous observation on nonmetallic surfaces, e.g., silica) in well-defined geometries in environments relevant to corrosion processes. We follow “crevice corrosion” processes in real time in different pH-neutral NaCl solutions and applied surface potentials of nickel (vs. Ag|AgCl electrode in solution) for the mica–nickel confined interface of total area ∼0.03 mm2. The initial corrosion proceeds as self-catalyzed pitting, visualized by the sudden appearance of circular pits with uniform diameters of 6–7 μm and depth ∼2–3 nm. At concentrations above 10 mM NaCl, pitting is initiated at the outer rim of the confined zone, while below 10 mM NaCl, pitting is initiated inside the confined zone. We compare statistical analysis of growth kinetics and shape evolution of individual nanoscale deep pits with estimates from macroscopic experiments to study initial pit growth and propagation. Our data and experimental techniques reveal a mechanism that suggests initial corrosion results in formation of an aggressive interfacial electrolyte that rapidly accelerates pitting, similar to crack initiation and propagation within the confined area. These results support a general mechanism for nanoscale material degradation and dissolution (e.g., crevice corrosion) of polycrystalline nonnoble metals, alloys, and inorganic materials within confined interfaces.

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