Aircraft coatings are the first line of defense when it comes to mitigating structural corrosion of an air platform. As new coatings are developed — particularly those that contain non-chrome primers — there is a need to qualify the coatings for use on military aircraft prior to implementation on flying systems. The process — which includes laboratory tests, outdoor environmental exposure, and aircraft trials — can be extensive and expensive.
Through a Small Business Innovation Research (SBIR) project with Luna Innovations Inc., the Air Force developed an improved system for coating materials performance evaluation that will accelerate the screening, qualification, and implementation of new aircraft coatings.
The new corrosion and coating evaluation system (CorRES) measures the ability of coatings to protect aircraft structures by using sensor panels that perform electrochemical measurements during corrosion testing. Unlike conventional coating tests that rely on an expert’s visual evaluation of a test panel at the conclusion of a test cycle, CorRES records corrosion rate data throughout a test and transmits the data to a base station for evaluation. This enables researchers to know not only if a coating fails, but exactly when this occurs during a test.
Legacy systems do not produce time-based, quantitative measurements inside a test chamber, but rather, these are taken after a panel is removed. CorRES enables monitoring of this variability and provides quantitative data better understand a coating’s performance.
The CorRES system produces a more comprehensive set of data for researchers than current corrosion testing systems through the use of a set of sensing elements that can measure free and galvanic corrosion, coating barrier properties, and the effects of the environment on coating materials in a single testing platform. Not only can the system be used in the laboratory environment, but it is also able to collect test data at outdoor exposure sites as well. Under performing coatings can be eliminated from screenings earlier in the testing process, thereby streamlining qualification efforts, and reducing the time and costs associated with coating tests.