Irina Gouzman - Academia.edu (original) (raw)

Papers by Irina Gouzman

The combined effect of hypervelocity space debris impacts and atomic oxygen (AO) on the fracture ... more The combined effect of hypervelocity space debris impacts and atomic oxygen (AO) on the fracture of polyimide films reinforced with polyhedral oligomeric silsesquioxanes (POSS) was studied. A laser-driven flyer (LDF) system was used to accelerate aluminum flyers to impact velocities of up to 3 km/s, and the impacted films were exposed to an RF plasma AO source. Scanning electron microscopy (SEM) was used to characterize the fracture morphology. The extent of damage in POSS-polyimide impacted films was found to be much smaller compared to POSS-free films, insinuating on a toughening mechanism developed due to POSS incorporation. When exposed to AO, the impacted POSS-free film revealed synergistic effect associated with a large increase in the erosion rate, while impacted POSScontaining samples showed improved resistance toward AO. The increased erosion rate of the impacted POSSfree film is explained by formation of residual stresses that affect the oxidation mainly by increasing the diffusivity of oxygen.

Space Technology Proceedings, 2006

Hypervelocity space debris impacts can lead to degradation of satellite performance and, in extre... more Hypervelocity space debris impacts can lead to degradation of satellite performance and, in extreme cases, might cause a total loss of a spacecraft. The increase in space debris population provides the motivation for this study, which focuses mainly on the mechanical behavior of space-qualified polyimide Kapton films impacted by simulated hypervelocity debris. Kapton is used extensively on spacecrafts, especially in thermal control blankets. Kapton films 25, 50 and 125 µm-thick were studied at different impact velocities of up to 2900 m/s generated by a Laser Driven Flyer (LDF) system. The Kapton-impacted sites revealed ductile-type fractures for lowvelocity debris, which changed gradually into mixed ductile-brittle fractures with crack formation when debris impact velocity was increased. High-velocity impacts generated spalls in the Kapton film, with ultrahigh strain rate of above 10 6 1/s. Fractures created by impacts at velocities above 1700 m/s showed central impact regions which experienced the highest strain rate and revealed a ductile-type fracture, while the outer regions which experienced a lower strain rate failed through brittle cracking. A model explaining this phenomenon, based on the temperature profile developed within the impacted region at the time of impact, is presented.

The Review of scientific instruments, 2011

The low Earth orbit (LEO) environment is considered hazardous to spacecraft, resulting in materia... more The low Earth orbit (LEO) environment is considered hazardous to spacecraft, resulting in materials degradation. Currently, in order to evaluate the degradation of materials in LEO, a retrieval of space exposed samples is required. In this study, a novel approach is proposed to evaluate degradation of materials in LEO without the need of retrieval. The method is utilizing photovoltaic cells (PVCs), an existing component onboard of any satellite. The PVCs are coated by various materials which are sensitive to different LEO constituents, such as atomic oxygen (AO) or ultra-violet (UV) radiation. The method's acronym is ORMADD (on-ORbit MAterials Degradation Detector). The ORMADD's principle of operation is based on measuring the PVC output power which depends on the cell coating material's optical transmission. Erosion of the coating by AO or coloring due to UV radiation affects its optical transmission and, accordingly, the PVC output. The ORMADD performance was tested us...

High Performance Polymers, 2004

The present study investigated the interactions of four different types of polyethylene (PE) surf... more The present study investigated the interactions of four different types of polyethylene (PE) surfaces with RF oxygen plasma components, simulating the low Earth orbit (LEO) environment. The samples were exposed in the plasma afterglow, with and without the plasma-generated vacuum UV (VUV) radiation. The polymers studied were low-density polyethylene (LDPE), ultra high molecular weight polyethylene (UHMWPE), high-density polyethylene (HDPE), and

Polymer, 2007

Polyimides are used as the outer layer of thermal control insulation blankets covering most of th... more Polyimides are used as the outer layer of thermal control insulation blankets covering most of the external spacecraft surfaces that are exposed to space environment. The combined effect of ground simulated hypervelocity space debris impacts and atomic oxygen (AO) on the fracture of polyimide films was studied. A laser-driven flyer system was used to accelerate aluminum flyers to impact velocities of up to 3 km/s. The impacted films were exposed to an RF plasma source, which was used to simulate the effect of AO in the low Earth orbit. Scanning electron microscopy and atomic force microscopy were used to characterize the fracture and surface morphology. When exposed to oxygen RF plasma, the impacted polyimide film revealed a large increase in the erosion rate, the damage being characterized mainly by the formation of new holes. This effect is explained by the formation of residual stresses due to the impact and enhancement of oxygen diffusivity and accumulation. A complementary experiment, in which a stressed polyimide was exposed to RF plasma, supports this model. This study demonstrates a synergistic effect of the space environment components on polymers' degradation, which is essential for understanding the potential hazards of ultrahigh velocity impacts and AO erosion for completing a successful spacecraft mission.

Physical Review B, 2004

First, a simple model describes theoretically the processes involved in the irradiation of solid ... more First, a simple model describes theoretically the processes involved in the irradiation of solid targets by femtosecond laser pulses and predicts the optimal target and laser parameters for efficient nanoparticles synthesis. Then, we show experimental evidence for successful synthesis of aluminum nanoparticles. Nanoparticles size distribution, morphology, atomic structure, and chemical composition are determined by various techniques, including x-ray diffraction, atomic force microscopy, scanning and transmission electron microscopy, and energy dispersive spectroscopy.

Laser and Particle Beams, 2005

In this paper, we suggest the creation of a nanoparticles and nanotubes by using the interaction ... more In this paper, we suggest the creation of a nanoparticles and nanotubes by using the interaction of a femtosecond laser with a solid target in a vacuum. A simple model is used to predict the optimal target and the laser parameters for the production of efficient nanoparticles. At the Soreq laboratory, experiments are performed with aluminium and carbon targets using a femtosecond laser. The irradiated targets are composed of either a thin layer of aluminium or of carbon, deposited on a transparent heat-insulating glass substrate. The nanoparticle debris is collected on a silicone wafer for X-ray diffraction~XRD!, for scanning electron microscopy~SEM!, and for atomic force microscopy~AFM!. For transmission electron microscopy~TEM!, the debris is caught on a copper grid covered on one side with a carbon membrane. Our experiments confirm the creation of crystal nanoparticles for aluminium and nanotubes for carbon experiments.

High Performance Polymers, 2008

The combined effect of hypervelocity space debris impact and atomic oxygen (AO) attack on the deg... more The combined effect of hypervelocity space debris impact and atomic oxygen (AO) attack on the degradation of reinforced polyhedral oligomeric silsesquioxanes (POSS)-polyimide films was studied. A laser-driven flyer (LDF) system was used to accelerate aluminum flyers to impact velocities of up to 3 km s 11 . The impacted films were exposed to an RF-plasma source, which was used to simulate the effect of AO in the low Earth orbit. Scanning electron microscopy (SEM) was used to characterize the fracture morphology. The extent of damage in POSS-polyimide impacted films was found to be much smaller compared to POSS-free films, insinuating on a toughening mechanism developed due to POSS incorporation. When exposed to air RF-plasma, the impacted POSS-free film revealed a synergistic effect associated with a large increase in the erosion rate while impacted POSS-containing samples showed improved erosion resistance. The increased erosion rate of the impacted POSS-free film is explained by formation of residual stresses that affect the oxidation mainly by increasing the diffusivity of oxygen. Downloaded from 476 R. VERKER ET AL.

Diamond and Related Materials, 1998

Nitrogen is one of the most widely studied impurities in diamond films. The reason is that nitrog... more Nitrogen is one of the most widely studied impurities in diamond films. The reason is that nitrogen takes part in a number of defects and therefore has a deep influence on the optical and electrical properties of diamond films. The mechanism of nitrogen incorporation in diamond is still an open question. This is mainly due to the complexity of the

American Institute of …, 2009

Page 1. NOVEL APPROACH TO SPACE-SURVIVABLE POLYIMIDES: LIQUID PHASE DEPOSITION OF TITANIA COATING... more Page 1. NOVEL APPROACH TO SPACE-SURVIVABLE POLYIMIDES: LIQUID PHASE DEPOSITION OF TITANIA COATING ON KAPTON Irina Gouzman1, Olga Gershevitz2, Eitan Grossman1, Noam Eliaz3 and Chaim N. Sukenik2 ...

Acta Materialia, 2004

Space debris population in low Earth orbit has been increasing constantly with the increase in sp... more Space debris population in low Earth orbit has been increasing constantly with the increase in spacecraft missions. Hypervelocity space debris impacts limit the functionality of polymeric outer surfaces and, in extreme cases, might cause a total loss of a spacecraft. In this work, the fracture of Kapton films by ultrahigh velocity impacts was studied. A laser-driven flyer ground simulation system was used to accelerate aluminum flyers to impact velocities as high as 2.9 km/s against polymer films with different thicknesses. Scanning electron microscopy was used to characterize the fracture morphology. Impact effects on the internal structure of the polymer were studied by means of X-ray microtomography. It was found that with an increase in debris velocity, a ductile-to-brittle transition occurred. However, fractures created by impacts at velocities above 1.7 km/s showed central impacts regions, which experienced the highest strain rate and were of ductile-type fracture, while the outer regions, which experienced a lower strain rate, failed through brittle cracking. A model explaining this phenomenon, based on the temperature gradient developed within the impacted region during collision, is presented.

Polyimides are widely used for the external surfaces of spacecraft. In low Earth orbit (LEO), the... more 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 backscattering (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 thermooptical properties and surface morphology. The erosion yield of titania-coated Kapton was only 2% of that observed for uncoated Kapton after exposure to 4 × 10 20 O-atoms cm -2 of LEO equivalent AO fluence.

Polyhedral Oligomeric Silsesquioxane (POSS)-polyimide (PI) thin films were synthesized from pre-m... more Polyhedral Oligomeric Silsesquioxane (POSS)-polyimide (PI) thin films were synthesized from pre-mixed solution of oxydianiline-pyromellitic dianhydryde (ODA-PMDA) and TriSilanolPhenyl (TSP) POSS. POSS-PI polymerization reaction kinetics was studied using Fourier Transform Infrared (FTIR) spectroscopy. The POSS-PI films were then investigated by tensile tests, followed by surface morphology examination using Atomic Force Microscopy (AFM) and Environmental Scanning Electron Microscopy (ESEM). An interdisciplinary approach was applied for establishing a relation between POSS-PI composites chemical microstructure properties and failure mechanisms. Inter molecular POSS-POSS interaction by either phase separation, or chemical POSS-POSS condensation reaction were observed as key factors, affecting the nanocomposite mechanical properties via formation of aggregates. The amount and density of these aggregates were shown to be composition dependent. A model based on formation and coalescence of voids during tensile tests was suggested for understanding the effect of the POSS content on the POSS-PI mechanical response.