Development of a Damage Function for Galvanic Corrosion Degradation of Coated Al Alloy Systems
Abstract
Prior work has shown that the galvanic interaction between uncoated more-noble fasteners and acoated Al alloy panel depends on many factors, each of which can play a dominant role:1. Al alloy and temper2. Surface pretreatment3. Organic coating system: primer and topcoat4. Condition of scribe or other coating defect5. Fastener details: material, design, and spacing6. Environmental exposure details: chloride, RH, time of wetness, exposure durationThis understanding has developed from series of experiments in which one of the parameters hasbeen changed over a range and galvanic current measured, primarily during exposure to ASTMB117 salt spray conditions. However, a systematic understanding of these factors is lacking. Apredictive model for galvanic corrosion as a function of these parameters as well as time is thefocus of this work. In particular, this proposal aims to determine damage functions predicting theextent of galvanic corrosion using artificial neural networks. The optical profilometer will be theprimary tool to assess the extent of attack. All panels will be scribed and only SS316 fastenerswill be used. The effect of fastener material and design will be addressed by using galvanostaticexposure with different currents. Different alloys, pretreatments, primers, exposure conditionswill also be tested. The result of these studies will be a tool that will provide quantitativeassessments of these parameters on galvanic corrosion.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 04, 2017
- Source ID
- N000141712034
Entities
People
- Gerald S. Frankel
Organizations
- Office of Naval Research
- Ohio State University
- United States Navy