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Bene 'Ayish, Israel

Gouzman I.,Space Environment Section | Girshevitz O.,Bar - Ilan University | Grossman E.,Space Environment Section | Eliaz N.,Tel Aviv University | Sukenik C.N.,Bar - Ilan University
ACS Applied Materials and Interfaces | Year: 2010

Polyimides are widely used for the external surfaces of spacecraft. In low Earth orbit (LEO), they are exposed to atomic oxygen (AO) and to problems of electrostatic discharge (ESD). This work demonstrates that liquid-phase deposition (LPD) of titania creates a protective coating on Kapton polyimide that is effective in reducing AO-induced surface erosion and in preventing ESD. Adherent titania coatings, 100-300 nm thick, were deposited on Kapton at near-ambient conditions by LPD using an aqueous solution of a metal-fluoride complex and boric acid. Characterization of the oxide-coated Kapton included atomic force microscopy (AFM) in tapping and nanoindentation modes, electrostatic force microscopy (EFM), scanning electron microscopy (SEM), Rutherford back-scattering (RBS) and X-ray photoelectron spectroscopy (XPS). The as-deposited titania-coated Kapton can be prepared without significant changes in the original thermo-optical properties of the polymer, while preventing ESD and improving the surface hardness. The durability of the oxide coating under AO attack was studied using an oxygen RF plasma. Surface erosion was measured both gravimetrically and by in situ quartz crystal microbalance (QCM) measurements. The AO exposure caused some changes in the thermo-optical properties and surface morphology. The erosion yield of titania-coated Kapton was only 2% of that observed for uncoated Kapton after exposure to 4 ×1020 O-atoms cm-2 of LEO equivalent AO fluence. © 2010 American Chemical Society. Source

Loeblein M.,Nanyang Technological University | Bolker A.,Space Environment Section | Tsang S.H.,Nanyang Technological University | Atar N.,Space Environment Section | And 5 more authors.
Small | Year: 2015

Polyimides (PIs) have been praised for their high thermal stability, high modulus of elasticity and tensile strength, ease of fabrication, and moldability. They are currently the standard choice for both substrates for flexible electronics and space shielding, as they render high temperature and UV stability and toughness. However, their poor thermal conductivity and completely electrically insulating characteristics have caused other limitations, such as thermal management challenges for flexible high-power electronics and spacecraft electrostatic charging. In order to target these issues, a hybrid of PI with 3D-graphene (3D-C), 3D-C/PI, is developed here. This composite renders extraordinary enhancements of thermal conductivity (one order of magnitude) and electrical conductivity (10 orders of magnitude). It withstands and keeps a stable performance throughout various bending and thermal cycles, as well as the oxidative and aggressive environment of ground-based, simulated space environments. This makes this new hybrid film a suitable material for flexible space applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Shpilman Z.,Space Environment Section | Shpilman Z.,Technion - Israel Institute of Technology | Gouzman I.,Space Environment Section | Grossman E.,Space Environment Section | And 2 more authors.
Applied Physics Letters | Year: 2010

The morphology and chemical bonding of the nucleation surface of polycrystalline diamond films were studied following the removal of the silicon substrate by acid etching and mild plasma cleaning. Atomic force microscopy characterization of this surface revealed a mosaic structure of cracks arranged in hexagonal patterns. These cracks are correlated with etched twin grain boundaries that surrounded hexagonal diamond crystals at the initial growth stages of the diamond films. High resolution electron energy loss spectroscopy studies indicate that mild annealing of the diamond film caused desorption of various oxides exposing a damaged diamond surface. © 2010 American Institute of Physics. Source

Zalevsky Z.,Bar - Ilan University | Rudnitsky A.,Bar - Ilan University | Haran A.,Space Environment Section | Zentner A.,Space Environment Section | And 2 more authors.
Aerospace Science and Technology | Year: 2011

This paper summarizes the irradiation test results of three components selected from novel optical Rotman lens configuration to be used for beam forming and steering in airborne application. The components include the Rotman lens itself, a fiber with an attached graded index lens and a photodiode. All were irradiated up to a total dose of 20 krad using a 60Co gamma source. The components were found to be insensitive to this total ionizing irradiation dose. Later on similar photo diodes were irradiated at 62 MeV protons with fluence of up to 1.5×1011 protons/cm2 and then measured after annealing of 17 days. No significant difference was observed in any of the parameters (measured after the gamma irradiation) with respect to a reference diode. Both experiments are indicating that the inspected components are potentially suitable for space. © 2010 Elsevier Masson SAS. All rights reserved. Source

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