Microwave Detection of Corrosion Pits in Painted Aluminum

1. Microwave Detection of Corrosion Pits in Painted Aluminum Russell Austin Texas Research Institute Austin, Inc. Reza Zoughi, Ph.D. Applied Microwave Nondestructive Testing Laboratory University of Missouri - Rolla Roger Englebart & Nancy Wood Boeing St. Louis

2. Overall SBIR Approach Modify existing TRI/AMNTL corrosion detection technology to detecting small pits Refine to detect and size 8 mil aluminum corrosion pits under Air Force paint & applique systems Two versions: MAUS mounted sensor kit Air Force already owns and trained on MAUS scanners handheld, battery operated stand alone unit

3. Significance of Microwave Approach Avoid Depainting & Repainting Time-consuming Costly Potentially exposes surface to corrosion initiation Significant aircraft downtime Early Detection Reduce damage sustained by structures, earlier repair Reduce downtime for acquisition of long lead items Simplify logistics and PDM planning

4. Repair Impact: Reduce Rework Grind out repairs Minimum allowable skin thickness Significant labor spent trying to repair parts too severely corroded to be successfully repaired Microwave corrosion depth gauge will allow scrapping the part without unnecessary rework

5. Repair Impact: Confirm Repair Complete Grinding repair determined complete when all of pitting has been removed Currently repair completion done visually Visual acuity varies widely person to person time of shift time of week Microwave system provides way to determine all pitting has been ground out

6. Samples Machined Flaws Laser machined pits 2024 & 7075 primer/topcoat & primer applique Corrosion Chamber Corrode via accelerated life testing ASTM-G64 method

7. Laser Machined Samples