TEM Studies of Protective Al Coatings on Kapton H
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TEM Studies of Protective Al Coatings on Kapton H Judith C.Yang, Huiping Xu*, Long Li, Deborah Waters 1, Bruce Banks1 Materials Science & Engineering, University of Pittsburgh, Pittsburgh, PA 1. NASA Glenn Research Center, Cleveland, OH * Corresponding author ABSTRACT Polymeric materials undergo rapid erosion when exposed to the harsh low-earthorbit (LEO) environment. Coatings can reduce the erosion rate of polyimide Kapton from atomic oxygen (AO) attack. Specifically, we are investigating how thin Al coatings can protect Kapton. Protective Al layers with variations in layer thickness and growth conditions were deposited on Kapton H. The quality of these protective coatings were evaluated by mass loss measurement and compared to Kapton alone and the SiO2 coating, where dramatically decreased erosion rate was noted. To understand how these coatings protect Kapton as well as how the AO interacts with the coatings, we are investigating the microstructure of these coated materials by plane view and cross-sectional transmission electron microscopy (TEM) methods. To understand the AO degradation mechanism, we attempted to correlate the mass loss with growth conditions and microstructures. We noted a slight improvement in erosion resistance of the Al coating due to the presence of the dendrimer, but a major improvement when the Al coating is deposited under ultrahigh vacuum conditions.
Introduction The effects of atomic oxygen (AO) on the external surfaces of low Earth orbital (LEO) spacecraft have long been a significant problem that can have dire consequences on the durability of spacecraft [1]. So far, considerable efforts have been undertaken to prevent or minimize materials degradation due to direct AO [2-5] and thin protective films, such as SiOx where 1.9
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