Accession Number:

ADA581696

Title:

Morphology and Mechanism of Benign Inhibitors

Descriptive Note:

Final rept. Mar 2008-Mar 2012

Corporate Author:

CINCINNATI UNIV OH COLL OF ENGINEERING

Personal Author(s):

• Schaefer, Dale W.
• Hu, Naiping
• Dong, Xuecheng
• Wang, Peng

Report Date:

2012-07-01

Pagination or Media Count:

115.0

Abstract:

This project demonstrates that most interfacial issues important to corrosion control can be elucidated by neutron and x-ray reflectivity. The evolution of a surface in a corrosive environment can now be measured in near real time. The data produced give corrosion scientists their first glimpse at active corrosion processes in water under potential control. The methodology was applied to Al protected by Trivalent Chromium Process TCP conversion coatings, vanadate conversion coatings and anodized aluminum. In all three cases, water penetrates the protective films. Corrosion protection is due to a thin interfacial layer as water penetrates all films studied. Failure on passive metals can be accelerated by application of an anodic potential. Failure of TCP-coated Al occurs by bulk water penetration of the film at the pitting potential. The compromised film remains on the metal creating an isolated environment conducive to pitting. A new anodic hardening method was developed by exposing TCP-coated Alto increasingly anodic potentials in the presence of a cerium chloride solution.

Descriptors:

• *CORROSION
• ALUMINUM
• CERIUM
• PROTECTIVE COATINGS
• REFLECTIVITY

Subject Categories:

• Coatings, Colorants and Finishes
• Properties of Metals and Alloys

Distribution Statement:

APPROVED FOR PUBLIC RELEASE