Flexible Atomic Oxygen Resistant Coating for Polyimide and Carbon/Carbon Composite Surfaces

Oxide coatings previously developed to protect polyimide and carbon/carbon composites in low earth orbit are brittle and crack upon flexing. Adding small amounts of polytetrafluoroethylene (PTFE) increases coating flexibility but reduces atomic oxygen (AO) resistance and mechanicall durability. Coatings developed in this project will use inorganics with potentially greater flexibility (such as sheet/layer structures). Organics used are physically tougher and optically superior (lower absorption/emittance, a/e) compared to PTFE. Deposition conditions will limit defect (pinhole) density and maximize adhesion and uniformity. Goals for coated materials, repeated bending around a 1 mm mandrel, are greater or equal to 0.6 and good resistance to thermal cycling, UV radiation and particle impact.