Aerospace Particle Coatings for Improved Environmental Protection

Magnetic aerospace particle materials, such as carbonyl iron powders (CIP), are crucial additives in aircraft coatings and composites for enhanced radar absorption. Protective treatments like surface alloying improve the survivability of these particles but increase volume and weight, impacting overall system efficiency. Alloying can add up to 30% more weight. Therefore, developing a lightweight encapsulating coating that offers the same level of environmental protection without alloying could significantly reduce weight. For magnetic radar absorbing material (MagRAM) applications like that of stealth aircraft the reduced weight increases fuel efficiency therefore extending mission readiness.To further weight saving of MagRAM particles GVD has created a chemical vapor deposited barrier coating suitable for protecting complex geometries from environmental degradation. This coating can be directly applied to carbonyl iron powders, which are then used in polymer composites or coatings. Replacing alloy treatments with this encapsulation method may yield weight savings of tens of pounds per airframe and cost savings of near 15%. The GVD coating encapsulates particles in a ~1-micron thick shell that shields them from water, salt fog, acids, and oils. Comprising only light elements (C, O, Si, H) and having a low density (~1.3 g/cmł), the coating adds minimal weight. Its robust protective qualities were proven in Navy collaboration, showing no corrosion after 500 hours of SO2 fog exposure.This project aims to scale up the encapsulation process to produce 250 grams of coated CIP weekly for testing in polymer composites. GVD will develop a system design and cost model to produce over 100,000 lbs of coated CIP annually. The approach involves using plasma-enhanced chemical vapor deposition (PECVD) to apply the barrier coating. PECVD is a high-throughput, air-free vapor treatment process that deposits high-quality, conformal coatings. In PECVD, precursor gases decompose into reactive species that form a thin film on surfaces, with control over the film's chemical structure, deposition rate, and morphology.GVD has commercialized similar coatings in tire molding, semiconductor manufacturing, and electronics protection; successfully transitioning three technologies to commercialization in the past five years. In this project, GVD will modify existing barrier coating tools and processes for particle substrates and use the use the two decades of coatings development and commercialization experience to successfully complete the project objectives, then quickly transition to commercial reactor production.