Validation and Demonstration of Relative Humidity Controlled Accelerated Corrosion Test: New Specification Development

Victor Rodriguez-Santiago | Naval Air Systems Command

WP18-5087

Objective

This research effort aims to develop, validate, and demonstrate the corrosion test methodologies designed during the Strategic Environmental Research and Development Program (SERDP)  WP-1673 project. Once validated and demonstrated, the test methodology will be written into a national standard for use in testing and qualification by laboratories across the Department of Defense (DoD), original equipment manufacturers, DoD contractors, and other testing laboratories.

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Technology Description

This project will finalize the development of a tunable test method that enables users to select exposure severity while providing experimental correlation, for both corrosion severity and mode, to observations from outdoor field exposures. The accelerated test will include control of relative humidity and periodic deposition of salt on test surfaces via a fog step in the cycle.

In the first stages of this project, final modifications to the test method will be made. Samples from these exposures will be compared to coupons exposed to outdoor conditions during the SERDP  WP-1673 project in order to ensure relevance. Sample comparisons will be made using a variety of techniques used to quantify and characterize corrosion damage, including image analysis and mass loss. A Go/No-Go decision will be made based on these comparisons. This determination will be made using both severity of attack and the types of damage modes present. Should the comparisons be successful, two tests will then be performed at eight locations to provide round robin statistics necessary for formalizing a test standard. This testing will also provide multiple DoD laboratories with the equipment and expertise to perform this testing. Finally, a test standard will be written and introduced as a National Association of Corrosion Engineers (NACE) specification—that will be adopted by Naval Air Systems Command (NAVAIR)—to formalize the test and enable it to be enforceable.

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Benefits

The benefit of creating a more representative accelerated corrosion test standard is two-fold: (i) it facilitates ease of implementation of corrosion prevention technologies and (ii) it generates a better understanding of risk. Being able to develop, test, and qualify new corrosion prevention schemes in a timely manner has the potential to reduce testing costs and provide the ability to introduce better technologies as they are developed. Currently, prospective technologies are developed much faster than they can be tested and qualified. For example, a single ASTM B117 test, the most utilized standard in the DoD for corrosion assessment, takes 2000 hours (83 days) to complete. However, this test replicates neither damage seen in outdoor exposure tests nor damage observed during aircraft maintenance, so prospective coatings are not implemented—even on a trial basis—until many years of outdoor exposure data are generated. Without any correlation to operational environment damage, it is impossible to assess the risk of implementing any given prevention scheme in a timely manner. This test method aims to provide representative predictions of corrosion in 1000 hours or less, reducing initial screening time and the need for lengthy field exposures prior to trial applications. Since the highest maintenance costs for DoD platforms result from corrosion, any gains in the ease of implementation of new products and the informed assessment of corrosion risk will be a much needed benefit to DoD platforms.

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Points of Contact

Principal Investigator

Victor Rodriguez-Santiago

Naval Air Systems Command

Phone: 301-342-8040

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