ManTech Outcome Vastly Improves Composite Material Durability

  • Published
  • By Heyward Burnett
  • Materials and Manufacturing
WRIGHT-PATTERSON AIR FORCE BASE, Ohio --  A partnership between the Air Force Research Laboratory, industry, and academia produced a novel erosion protection technology that greatly increases the capacity of composite materials to withstand degradation from erosive sand, wind, and rain--forces that might otherwise lead to catastrophic failure of mission-critical components. With AFRL Manufacturing Technology funding support, researchers from Nanosperse, Inc., and the University of Dayton Research Institute created the new multilayer, nano-enhanced film, which offers distinct advantages over traditional paint coatings. The environmentally friendlier technology eliminates the volatile organic compounds, toxic primers, and oven baking cycles associated with paint and, further, supplies a fivefold improvement in terms of erosion resistance. Designed and developed for mission-critical military applications, the superior capability has undergone successful transition and qualification in this regard, with the film effectively co-cured into the surface of the F101 engine's inlet guide vane for service in the B-1 Bomber.

Though their lightweight aspect marks composites as preferred materials for weapon systems, they degrade rapidly when subjected to elements such as sand, wind, and rain. Among the possible consequences of this vulnerability are decreased service life and mission readiness, as well as increased inspection and repair costs. The ManTech/NanoSperse/UDRI team worked to address this shortcoming by devising a more effective and seamless mechanism for designing, developing, and transitioning new nanocomposites for use in Air Force systems. Accordingly, the researchers concentrated their efforts not only on incorporating wear-resistant nanomaterials at the surface of composite parts, but on creating a protective film to coat those components. The resultant film comprises three hybrid layers, delivered to parts manufacturer as one film. Consisting of compatible, 350°F-cured epoxy resin co-cured into a given part, the new film eliminates all painting operations and the undesirable by-products thereof.

The co-curing process involves laying the film around a preform and injecting resin between surfaces. (North Coast Composites developed special tooling to facilitate this procedure.) This unique filler technique produces a coated outer surface that provides exceptional erosion protection. In addition to benefits already noted, the new film improves the impact and damage tolerance of coated composite materials and is also fully repairable, characteristics fueling plausible expectations that the technology will likely generate up to a 73% reduction in composite life-cycle costs (including parts and repair expenditures). The technology has importance beyond its initial application during parts production as well, given that additional multifunctional surfaces can later be co-cured into composite structures via high loadings of specialized fillers in order to impart properties such as electromagnetic interference shielding, anti-icing, and fire protection.

With the film having undergone transition and qualification for military engine parts, NanoSperse is now working with AFRL and UDRI to identify other Department of Defense applications as future technology transition candidates.