Development of a Dynamic Multivariate Accelerated Corrosion Test Protocol

The objective of this project is to develop a comprehensive test protocol to accurately predict all aspects of the performance lifetime of Department of Defense (DoD) coatings. The resultant test protocol should ideally be independent of substrate composition and accurately rank the performance of any coating system equivalent to the results obtained by long duration outdoor and field exposure. DoD service environments are variable in nature (e.g., beachfront versus desert), and the test protocol should either be specific to a particular service environment or should be dynamically tunable to match the particular service environment in which the coating is intended to be used. The test protocol should also provide accurate results for particular material configurations such as fasteners and lap joints, which can create concentration cells and galvanic couples. The test method should allow a reasonable prediction of performance lifetime based on a relatively short time frame accelerated laboratory exposure test. To accomplish this, identification of appropriate exposure sites, preparation of bare and coated exposure panels and deployment of  these panels along with environmental monitoring systems have been deployed at 8 locations: Pt. Judith, RI; Wright-Patterson AFB, Dayton OH; Daytona Beach, FL; Tyndall AFB, FL. Kirtland AFB, NM; Hickam AFB, HI; and 2 sea surface ships of the University National Oceanographic Laboratory System (UNOLS): the R/V Thomas G. Thompson (Univ. Washington, Seattle) and the R/V Hugh R. Sharp (Univ. Delaware, Lewes).  The environmental monitoring systems record ozone, UV, temperature and relative humidity. Exposure panels are retrieved at 3 month intervals and surface chemical analyses are performed using SEM-EDS, XPS, and TOF-SIMS techniques. The combined environmental and surface chemistry data collected will be used to develop an accelerated laboratory exposure test protocol utilizing a modified environmental exposure chamber that incorporates UV, ozone and solution chemistries determined from the various exposure sites.