EROSION RESISTANCE AND DURABILITY IMPROVEMENT OF POLYMERS AND COMPOSITES IN SPACE ENVIRONMENT BY ION-IMPLANTATION

Spacecraft designers use polymers and polymer-based composite material s extensively in electrical, thermal, and structural applications to a ddress both weight and performance demands. Without protection from th e deleterious effects of the space environment, in particular hyperthe rmal atomic oxygen (HAO), these materials suffer accelerated erosion f rom chemical interaction and experience a loss of mass and deteriorati on of performance. High dose implantation at energies in the 10-100 ke V range using ions of metal or semiconductor materials was used as a m ethod of modifying the surface of these polymeric materials to produce changes that can yield dramatic improvements in space environmental d urability. The results of this study show that computer modelling of t he ion implantation process combined with reasonable fluence estimates give a good basis for the choice of implantation conditions. This stu dy presents the results for high-performance materials including Kapto n(R), Mylar(R), PEEK, Lexan(R), and PEEK/carbon fibre composites using X-ray electron spectroscopy, scanning electron microscopy, and other surface analysis techniques, before and after treatment. The results s how that implantation of silicon and aluminum (singly, binary, or in c ombination with boron) or yttrium implantation produces a stable, prot ective oxide-based layer following exposure to HAO. The improvement in chemical resistance of these materials assures performance without de terioration in long duration space missions and shows promise for impr ovement in terrestrial performance in highly reactive oxidative enviro nments. (C) 1998 Elsevier Science S.A. All rights reserved.