Novel High-Strength Bioinspired Coatings for Hypervelocity Debris Mitigation

Materials designed for use in extreme environments must have strong mechanical and/or thermal resistance to withstand the insults experienced for their desired application. Some of the most stressing environments, which require both mechanical and thermal resistance, are use in pulsed power facilities, magnetic fusion reactors, and space debris and radiation protection. Ideal materials for these applications must combine high strength and thermal resistance with low weight high x-ray transmission. Materials which meet these needs and do not cause significant hazards to personnel and the environment are not presently available.<br/>Novel layered nanocomposite coatings have been fabricated from silica and sugar-derived carbon biomimic natural seashell structures. These coatings have been demonstrated to have high x-ray transmission, which enables their use as diagnostic windows for pulsed power facilities and magnetic fusion reactors. The coatings are stable to temperatures exceeding 800 °C, which outperforms other high-strength, low-weight materials. The materials are environmentally friendly and do not pose any health risks to personnel, which enables them to be used for diagnostics in extreme environments.<br/>Testing of their functionality as debris shields for pulsed power facilities, magnetic confinement fusion reactors, and micrometeoroid impact is ongoing. Variable thickness of coatings on silicon substrates were exposed to debris generated on the Z Pulsed Power Facility at Sandia National Laboratories and the deformation to a witness plate shielded by the coatings was measured. Deformation of the witness plate behind a 50 µm thick substrate coated with 35 µm of this material was less than that of a 100 µm thick bare substrate. Coating of 40 µm of material on a 100 µm thick substrate resulted in no measurable deformation to the witness plate. The results demonstrate that this coating is viable for use as debris shields in extreme environments.<br/><i>Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.</i>