Browse Topic: Graphite

Items (239)

Molded or Extruded Bar, Rod, and Shapes Produced from 20% Graphite – 3% Polytetrafluoroethylene (PTFE) Filled Polyamide-Imide (PAI) Material

AMS3670/2C (Current)5/19/2021

This specification covers molded or extruded bar, rod, and shapes produced from a polyamide-imide (PAI) polymer filled with 20% graphite and 3% polytetrafluoroethylene (PTFE). This is designated as Grade 2 material per AMS3670.

AMS P Polymeric Materials Committee

Bar, Rod, and Shapes Produced from 12% Graphite - 3% Polytetrafluoroethylene (PTFE) Filled Polyamide-Imide (PAI) Material

AMS3670/3C (Current)5/19/2021

This specification covers molded or extruded bar, rod, and shapes produced from a polyamide-imide (PAI) polymer filled with 12% graphite and 3% polytetrafluoroethylene (PTFE). This is designated as Grade 3 material per AMS3670.

AMS P Polymeric Materials Committee

Creation of an Icephobic Coating using Graphite Powder and PTFE Nanoparticles

2019-01-19796/10/2019

Ice accretion can cause numerous inefficiencies, structural stresses, and failures in applications ranging from building design to power generation and aerospace applications. Currently, some of the leading de-icing technologies, such as the ICE-WIPS system, utilize a heating element coupled with a superhydrophobic surface. The high power consumption inherent in these systems can make them expensive and impractical, especially when coupled with power generating systems. Reduced power consumption in these de-icing technologies can be achieved through increased absorption of solar radiation in the visible range while maintaining hydrophobic performance of a coating. In this work, a Polytetrafluorethylene (PTFE) and graphite-based superhydrophobic surface is proposed, which maintains similar hydrophobic performance to standard superhydrophobic surfaces. The novel coating demonstrates contact angles of upwards of 130o and sliding angles of less than 4o, while increasing solar radiation absorption in the visible range by approximately 139% over PTFE-based hydrophobic coatings. Icing wind tunnel tests where the coatings were exposed to visible light in order to simulate solar radiation were performed in a variety of different conditions in order to verify the improved de-icing capabilities introduced by the added graphite. The melting time per unit ice mass was reduced by upwards of 50% for glaze ice and 8.0% for rime ice over a comparable de-icing coating without added graphite. There was also a qualitative difference in de-icing performance, as the coating with added graphite demonstrated removal of ice in a single sheet from the base layer, in contrast to the PTFE only coating, which allowed for the ice to melt in multiple pieces from the model.

Gonzales, Joseph, Sakaue, Hirotaka

Design Development of Lightweight Thermoplastic Composite Cargo Floor for Helicopter Application

F-0074-2018-12820

5/14/2018

ABSTRACT The ability to construct a composite, semimonocoque, damage-resistant, cargo floor for a rotary wing application using an IM7 graphite/polyetheretherketone (PEEK) composite with in-situ tape-placement fabrication technology has been demonstrated. Through an evolutionary process, a damage-tolerant thermoplastic composite cargo floor was designed according to realistic requirements, and subelement representative structures were developed to verify the design viability and approach. The fabricated and tested structural composite floor subelements demonstrated the feasibility of the technology, illustrated the ability to customize the design to meet unique cargo floor properties (e.g., cargo-loading features), and validated the maturity of the approach and fabrication technology for rotary-wing applications.

Luzetsky, Harry, Michasiow, John

Automotive Compacted Graphite Iron Castings

J1887_201802 (Current)2/15/2018

This SAE Standard covers the mechanical and physical requirements for Compacted Graphite Iron (CGI) castings used in automotive and allied industries. Requirements in this document include: a Tensile Strength b Yield Strength c Elongation d Graphite Morphology

Metals Technical Committee

Ultra-Strong, Lightweight, Elastic, Electrically Conductive Carbon

TBMG-282962/1/2018

The configuration of carbon's electrons allows for numerous self-bonding combinations that give rise to a range of materials with varying properties. For example, transparent, super-hard diamonds and opaque graphite, which is used for both pencils and industrial lubricant, are comprised solely of carbon.

Bulk Preparation of Holey Graphene via Controlled Catalytic Oxidation

TBMG-281731/1/2018

Researchers at NASA have developed new methods to manufacture carbon materials (e.g., nanotubes, graphene) with holes through the graphitic surface of the particles. The methods generate materials with increased accessible surface area, increased functional groups at damage sites, and improved through-surface molecular transport properties. The materials generated using these techniques are anticipated to be applicable to a variety of industries, especially energy storage (e.g. supercapacitors and batteries) and separation membranes (e.g. for gas, ions, organics, proteins, etc.).

Contaminants for Aircraft Turbine Engine Fuel System Component Testing

AIR4246D (Current)9/27/2017

This SAE Aerospace Information Report (AIR) is intended as a guide toward standardization of descriptions and specifications of fluid contamination products.

AE-5B Aircraft and Engine Fuel and Lubricant Sys Components

Magnesium Alloys, Anodic Treatment of

AMSM45202B (Current)9/20/2017

This specification covers the requirements for equipment, materials and procedures to be used in anodic treatments for magnesium base alloys for the purpose of increasing their corrosion resistance or producing surfaces suitable for the application of a protective organic finish.

AMS B Finishes Processes and Fluids Committee

Studies on Carbon Fiber Reinforced Aluminum Based Composites

2017-28-19847/10/2017

Importance of fibers as reinforcements in metal matrices has long been recognized. It is only because of this realization that many industries like aerospace and to some extent the automobile industry relies entirely on advanced composite materials for their conflicting demands of high performance and lightweight materials. However most of the work in these areas has been limited or confined to patents created by the defense and automotive sectors. The efforts to commercialize these materials have been restricted due to high cost of the reinforcements and the manufacturing processes used. In this work an attempt has been made to infiltrate the Carbon fibers by imparting Nickel and Salt based coatings to fiber surfaces with commercial purity aluminum and A356 alloy. Infiltration has been performed in ambient atmosphere and also under vacuum. The carbon fibers have been successfully infiltrated with K2ZrF6 salt coatings and were hot pressed to required shapes. The alloy was age-hardened and the hardness of the A356 alloy and its carbon fiber reinforced composites was compared. Tensile strength of the alloy was evaluated at peak hardness for both the alloy and the composite and the properties of the A356 composite on incorporating with around 45% volume fraction of carbon fibers.

Hussain, Naveed

Lightweight, Low-Cost, Damage-Tolerant, Highly Survivable Composite Drive Shaft for Helicopter Application

F-0073-2017-12153

5/9/2017

ABSTRACT The ability to construct a composite, damage-resistant, highly survivable drive shaft for a rotary-wing application using an IM7 graphite/polyetheretherketone (PEEK) composite and in-situ tape-placement fabrication technology has been demonstrated. Through an evolutionary process, highly survivable, damage-tolerant shafts were developed, design tools and data were validated, and test shafts developed to evaluate the design viability in a dynamic application. The drive shafts demonstrated the feasibility of the technology, illustrated the ability to customize the design to meet unique shaft properties (e.g., frequency), and validated the maturity of the technology for rotary-wing applications.

Luzetsky, Harry, Michasiow, John, Phifer, Ellen

Multifunctional Structural Composite with Integrated Electromagnetic Shielding

F-0073-2017-12174

5/9/2017

ABSTRACT The ability to construct a multifunctional material that provides electromagnetic (EM) hardening on an aircraft structure integral to the material form has been demonstrated. The material's key attribute is the integration of a high level of EM shielding directly into a structural fiber-reinforced graphite composite in a manner that has minimal to no impact on the mechanical characteristics of the host composite. The material form has demonstrated the EM shielding equivalency of an aluminum electronics enclosure structure on a composite alternative for 25% of the weight without impacting structural characteristics. This material form provides a lightweight alternative to traditional means of providing aircraft EM protection from existing and emerging threats, such as high-power microwaves (HPMs) and EM pulse (EMP)/high-altitude EMP (HEMP), without incurring parasitic weight penalties. Its multifunctionality provides a weight-efficient means to address EM shielding in a composite while taking advantage of its strength-to-weight properties.

Luzetsky, Harry, Ostrander, Graham, Klein, Martha

Fatigue Assessment of Nodular Cast Iron with Material Imperfections

2017-01-03443/28/2017

For the design of thick-walled nodular cast iron components, fatigue assessment, especially in the context of local imperfections in the material, is a challenging task. Not only the cyclic material behavior of the sound baseline material, but also the cyclic behavior of materials with imperfections, such as shrinkages, dross and chunky graphite, needs to be considered during the design process of cast iron components. In addition to this, new materials, such as solid solution strengthened alloys, offer new possibilities in lightweight design, but need to be assessed concerning their fatigue strength and elastic-plastic material behavior. If a safe and reproducible fatigue assessment for any component cannot be performed and a secure usage is therefore not given, the cast components are generally rejected, leading to a loss of additional material, energy and money for recasting the component. In this context, four nodular cast iron materials are compared with reference to their cyclic material and fatigue behavior as well as their potential for a lightweight design, based on stress- and strain-controlled tests both for sound and defective material. However, to develop an optimal and individual fatigue design method for cast components with local material imperfections present, the component’s local fatigue strength needs to be combined with information from non-destructive testing (NDT), since a removal of specimens is generally not possible. For this purpose, as an example, a method is described that uses information from ultrasonic and X-ray analysis as well as the given fatigue strength of the baseline material to conduct a fatigue assessment of local shrinkages in nodular cast iron components. The method is based on the reproducible measurement of the local density by NDT and its correlation with the local fatigue notch factor, enabling a safe and local assessment of the allowable fatigue strength when shrinkages are present.

Bleicher, Christoph, wagener, Rainer, Kaufmann, Heinz, Melz, Tobias

Lifetime Assessment of Cylinder Heads for Efficient Heavy Duty Engines Part II: Component-Level Application of Advanced Models for Thermomechanical Fatigue Life Prediction of Lamellar Graphite Cast Iron GJL250 and Vermicular Graphite Cast Iron GJV450 Cylinder Heads

2017-01-03463/28/2017

A complete thermomechanical fatigue (TMF) life prediction methodology is developed for predicting the TMF life of cast iron cylinder heads for efficient heavy duty internal combustion engines. The methodology uses transient temperature fields as thermal loads for the non-linear structural finite-element analysis (FEA). To obtain reliable stress and strain histories in the FEA for cast iron materials, a time and temperature dependent plasticity model which accounts for viscous effects, non-linear kinematic hardening and tension-compression asymmetry is required. For this purpose a unified elasto-viscoplastic Chaboche model coupled with damage is developed and implemented as a user material model (USERMAT) in the general purpose FEA program ANSYS. In addition, the mechanism-based DTMF model for TMF life prediction developed in Part I of the paper is extended to three-dimensional stress states under transient non-proportional loading conditions. The material properties of the plasticity model are determined for lamellar graphite cast iron GJL250 and vermicular graphite cast iron GJV450 from isothermal and non-isothermal uniaxial tests. The methodology is applied to obtain a TMF life prediction on two cast iron cylinder heads for heavy duty diesel engine applications made from both cast iron materials. It is shown that the life predictions using the developed methodology correlate very well with observed lives from two bench tests in terms of location as well as number of cycles to failure.

Hazime, Radwan, Seifert, Thomas, Kessens, Jeremy, Ju, Frank

Lifetime Assessment of Cylinder Heads for Efficient Heavy Duty Engines Part I: A Discussion on Thermomechanical and High-Cycle Fatigue as Well as Thermophysical Properties of Lamellar Graphite Cast Iron GJL250 and Vermicular Graphite Cast Iron GJV450

2017-01-03493/28/2017

Cast iron materials are used as materials for cylinder heads for heavy duty internal combustion engines. These components must withstand severe cyclic mechanical and thermal loads throughout their service life. While high-cycle fatigue (HCF) is dominant for the material in the water jacket region, the combination of thermal transients with mechanical load cycles results in thermomechanical fatigue (TMF) of the material in the fire deck region, even including superimposed TMF and HCF loads. Increasing the efficiency of the engines directly leads to increasing combustion pressure and temperature and, thus, lower safety margins for the currently used cast iron materials or alternatively the need for superior cast iron materials. In this paper (Part I), the TMF properties of the lamellar graphite cast iron GJL250 and the vermicular graphite cast iron GJV450 are characterized in uniaxial tests and a mechanism-based model for TMF life prediction is developed for both materials. The model can be used to estimate the fatigue life of components by means of finite-element calculations (Part II of the paper) and supports engineers in finding the appropriate material and design. Furthermore, the effect of the elastic, plastic and creep properties of the materials on the fatigue life can be evaluated with the model. However, for a material selection also the thermophysical properties, controlling to a high level the thermal stresses in the component, must be considered. Hence, the need for integral concepts for material characterization and selection from a multitude of existing and soon-to-be developed cast iron materials is discussed.

Seifert, Thomas, von Hartrott, Philipp, Boss, Kristopher, Wynthein, Paul

Surface Functional Groups and Graphitization Degree of Soot in the Sooting History of Methane Premixed Flame

2017-01-10033/28/2017

The evolution of surface functional groups (SFGs) and the graphitization degree of soot generated in premixed methane flames are studied and the correlation between them is discussed. Test soot samples were obtained from an optimized thermophoretic sampling system and probe sampling system. The SFGs of soot were determined by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) after removing the soluble impurities from the soot samples, while the graphitization degree of soot was characterized by Raman spectrum and electron energy loss spectroscopy (EELS). The results reveal that the number of aliphatic C-H groups and C=O groups shows an initial increase and then decrease in the sooting history. The large amount of aliphatic C-H groups and small amount of aromatic C-H groups in the early stage of the soot mass growth process indicate that aliphatic C-H groups make a major contribution to the early stage of soot mass growth. The higher graphitization degree of soot appears at low height above the burner when the graphite core is formed. The graphitization degree of soot rapidly decreases in the early mass growth stage then increases in the maturation process. The results from transmission electron microscopy (TEM), SFGs, and the graphitization degree verify the assumption that the nascent soot consists of a graphite-like core and an aliphatic shell. There is a strong correlation between SFGs and graphitization degree in the early stage of the soot mass growth process. During the soot maturation process, the correlation between SFGs and graphitization degree weakens. The SFGs may be related to the aggregate soot particle properties, such as fractal dimension.

Liu, Ye, Lv, Gang, Fan, Chenyang, Li, Na, Wang, Xiaowei

Marking of Plastic Parts

J1344_201703 (Current)3/28/2017

Plastics Committee

Comparative Small Engine Testing Using Hybrid Composite Cylinder Liners

2016-32-002211/8/2016

Cylinder liners exert a major influence on engine performance, reliability, durability and maintenance. Various combinations of nonmetallic reinforcements and coatings have been used to improve the tribological performance of sleeves or surfaces used in compressors and internal combustion engines in four stroke, two stroke and rotary configurations. In this paper we report the use of a hybrid composite containing silicon carbide and graphite in an aluminum alloy matrix to improve the performance of various small engines and compressors. Material properties of the base material, as well as comparative dynamometer testing, are presented.

Weiss, David, Beno, Simon, Jordan, Chris, Rohatgi, Pradeep

Metal/Fiber Laminate and Fabrication Using a Porous Metal/Fiber Preform

TBMG-251738/1/2016

NASA’s Langley Research Center has developed a new technique to enable the preparation of metal/composite hybrid laminates, also known as fiber metal laminates (FML), by depositing metal directly onto fabric using a plasma deposition process. FMLs provide a useful combination of structural and functional properties for both aerospace and non-aerospace applications. Currently, FMLs are prepared in a compression process utilizing a press or autoclave with metallic layers (foils) sandwiched between layers of glass or graphite prepreg (preimpregnated fibers with a matrix resin). The NASA process deposits the metal on the fiber via plasma deposition. The porosity of the coated fabric allows for resin infusion.

A Combined Discrete and Continuum Fatigue Damage Characterization of a Hybrid Composite Flexbeam

F-0072-2016-11541

5/17/2016

Strength and life prediction of a nonlinear tapered hybrid composite flexbeam under combined axial tension and bending is a challenging problem due to the presence of a complex geometry, a hybrid composite material system with a combination of glass/epoxy and graphite/epoxy composites, and a variable thickness profile along the beam longitudinal direction. A hybrid approach based on the combination of discrete crack network (DCN) and continuum damage mechanics (CDM) is applied for fatigue damage prediction under pure bending and bending with axial loading. Abaqus solid shell elements (SC8R) with composite section were used to capture the stress distribution and its concentration at the ply drop location. A hybrid modeling strategy is developed based on Abaqus solid shell elements (SC8R) with a user-defined material model for non-critical damage zones, user-defined phantom paired solid elements for critical damage zones, and Abaqus elements for non-damaged regions. A comparative study is performed for a representative flexbeam with and without the application of an axial force.

Lua, Jim, Phan, Nam, Fang, Eugene, Rahman, Anisur

Type 7 Virgin Polytetrafluoroethylene (PTFE) Moldings or Extrusions with 25% Carbon and Graphite

AMS3678/7B (Current)2/29/2016

This specification covers a polytetrafluoroethylene (PTFE) resin filled with carbon and graphite in the form of extruded or molded rods or tubes which are sintered after molding or, in the case of extrusions, sintered during the extrusion process.

AMS P Polymeric Materials Committee

Type 2 15% Graphite Filled Virgin Polytetrafluoroethylene (PTFE) Moldings or Extrusions

AMS3678/2B (Current)2/29/2016

This specification covers a polytetrafluoroethylene (PTFE) resin filled with 15% graphite in the form of extruded or molded rods or tubes which are sintered after molding or, in the case of extrusions, sintered during the extrusion process.

AMS P Polymeric Materials Committee

Performance of Low-metallic Cu-free Brake Pads with Two Different Graphite Types

2015-01-26779/27/2015

Automotive brake lining materials are complex composites consisting of numerous ingredients allowing for their optimal performance. Since regulations are increasingly limiting Cu content in brake pads and Cu exhibits extremely high thermal conductivity, graphites being excellent heat conducting materials themselves, are often considered for use as potential Cu replacement. This paper surveys the role of two types of carbons (Superior Graphite) with high thermal conductivity but different mechanical properties and morphology: the so-called i) purified flake graphite (PFG) and the ii) resilient graphitic carbon (RGC). A successful “high-end” commercial low-metallic brake pad was re-formulated (SIU Carbondale) by removing of over 20 wt. % of Cu and replacing it with a cocktail of ingredients including 15 wt. % of these two graphite types (RGC and PFG). Original equipment manufacturer (OEM) Crown Victoria 1999 mold was used to prepare the pads and they were subjected to the SAE J2430 test and BEEP evaluation using the full-scale automotive brake dynamometer (Link Engineering M 2800) and original hardware (rotor and caliper). After friction tests, the surfaces of pads were explored using scanning electron microscopy equipped with the energy dispersive X-ray microanalysis (FEG450 and Inca System) and X-ray diffraction (Rigaku Max-Flash-B). The performance of two different low-metallic pads was different. Both formulations exhibited extremely good stability of friction during fade section. The different friction levels and different wear of samples were related to the specific surfaces developed on two different pads containing RGC and PFG graphites and encountering rotors were covered by a discontinuous (patchy) friction layer. The capacity of the PFG to reduce surface oxides is considerably higher when compared to the RGC. Proper understanding of role of individual graphitic forms in particular formulations can be very beneficial when optimizing the performance of brake pads.

Daei, Amir Reza, Majumdar, Diptarka, Filip, Peter

NASA PS400 High-Temperature Solid Lubricant Coating

TBMG-22854

9/1/2015

NASA has an ongoing need for high-temperature solid lubricant coatings to reduce friction and wear in turbine engines, rocket engines, and other mechanical systems. Such lubricants must be thermally and chemically stable in air, vacuum, and reducing environments like hydrogen. Traditional lubricants like oil, grease, and PTFE (Polytetrafluoroethylene), and even more exotic solid lubricants like graphite and molybdenum disulphide, lack such capabilities. The key problem is to identify and formulate a material that possesses good mechanical properties, long-term environmental durability, and acceptable friction and wear-reducing characteristics while being practical to apply to bearings, seals, and other mechanical components.

Could Black Phosphorus be the Next Silicon?

TBMG-227488/14/2015

As scientists continue to hunt for a material that will make it possible to pack more transistors on a chip, new research from McGill University and Université de Montréal adds to evidence that black phosphorus could emerge as a strong candidate. In a recent study, researchers reported that when electrons move in a phosphorus transistor, they do so only in two dimensions. This finding suggests that black phosphorus could help engineers surmount one of the big challenges for future electronics – designing energy-efficient transistors.

DC Transformer

TBMG-225488/1/2015

A component-level DC transformer was developed in which no alternating currents or voltages are present. It operates by combining features of a homopolar motor and a homopolar generator, both DC devices, such that the output voltage of a DC power supply can be stepped up (or down) with a corresponding step down (or up) in current. The DC transformer should be scalable to low-megawatt levels, but is more suited to high-current than high-voltage applications.

Degradation Analysis of Pouch Cell Using High-Energy Cathode Material for Advanced Lithium-ion Battery

2015-01-11934/14/2015

Lithium-rich layered oxide, expressed as xLi2MnO3-(1-x) LiMO2 (M = Ni, Co, Mn, etc.), exhibits a high discharge capacity of 200 mAh/g or more and a high discharge voltage at a charge of 4.5 V or more. Some existing reports on cathode materials state that lithium-rich layered oxide is currently the most promising candidate as an active material for high-energy-density lithium-ion cells, but there are few reports on the degradation mechanism. Therefore, this study created a prototype cell using a lithium-rich layered cathode and a graphite anode, and analyzed the degradation mechanism due to charge and discharge. In order to investigate the causes of degradation, changes in the bulk structure and surface structure of the active material were analyzed using high-resolution X-ray diffraction (HRXRD), a transmission electron microscope (TEM), X-ray absorption fine structure (XAFS), and scanning electron microscope/energy dispersive X-ray spectroscopy (SEM-EDX). The results showed that dissolution of transition metals from the cathode active material is the main factor producing degradation of the full cell capacity, and that this is promoted by excessive reductive decomposition of the electrolyte due to deposition of the transition metals on the anode. In addition, voltage fade originates in the cathode active material, and is promoted by changes in the local structure resulting from oxygen release from the crystals due to charge and discharge.

Maeyama, Hiroto, Sukigara, Toru

Cryogenic Treatment of SG Iron for Disc Brake Application

2015-01-06894/14/2015

Cryogenic treatment has a good potential to significantly increase the service life of automotive components, where friction and wear are the major factors in their operation leading to failure. Cryogenic treatment changes the surface as well as the core properties of the component in comparison with other treatments. It has significant improvement in wear and toughness. Numerous studies have been conducted on cryogenic treatment of steels and tool steels showing significant improvements in wear resistance, only minimal work has been done in cast irons. In this study, the effect of cryogenic treatment on the wear resistance, hardness, tensile strength, toughness and microstructure of spheroidal graphite iron was assessed. The deep cryogenic treatment was carried out at 87K for 12h and annealed in the chamber itself. The samples were tempered at 473K for 1 h. The hardness, toughness and tensile strength of base material, cryotreated and cryotreated tempered samples were measured using Rockwell hardness, Impact testing machine and Universal testing machine respectively. Wear studies were performed using pin-on-disc wear testing machine with EN 31 steel as the disc. There was a significant increase in hardness, toughness and tensile strength due to cryogenic treatment. The results indicate an improvement in the wear rate of SG iron of 6.1-38.2% due to cryogenic treatment where significant wear has occurred and further improved to 52.9% due to tempering after cryogenic treatment. This finds suitable for disc brake application in automobiles.

Rajendran, R., Ramanjaneyulu, G., Tamilarasan, T R, Semenov, Vladimir I.

Aging in Salt Water of Composite Material of Polyester Resin and Piassava Fiber

2014-36-04649/30/2014

Natural fibers have being used on manufacturing of composite materials for car components. Between natural fibers, sisal and piassava deserve special attention. These components can be exposed to many environmental conditions, for example humid and saline environments, present in littoral regions of coastal countries. This study aims to evaluate the effects of salt water on the properties of a polyester matrix composite material reinforced with piassava natural fibers; and for this, using cheap and easily accessible materials and equipment. The polymeric matrix used was terephthalic unsaturated polyester resin, the curing agent was MK (Butanox M-50), in proportion of 0.33% (v/v). The fiber used was piassava, obtained at the popular trade center in the city of Belém-PA, the fibers were acquired in natural environmental conditions and without treatments. These materials were used to create specimens in the ASTM D 638 M standard, which got under aging process in salt water. The water absorption was measured by weighing the specimens during the aging in determined times. After their respective exposure time the samples passed through a tensile test to evaluate their properties and compare the effects of different exposure times. The results show an effective decrease in properties of elasticity and tensile resistance by the composite, directly proportionally to the aging time. It's possible to conclude that the salt water absorption degrades both fiber and resin.

Souza, João Henrique Santos, Silva, Douglas Santos, Silva Jorge, Marcos Rafael da, Teixeira, Felipe Pinheiro, Filho, Carlindo Lins Pereira, Fujiyama, Roberto Tetsuo

Advanced Composite Thrust Chambers for In-Space Propulsion

TBMG-203078/1/2014

Radiation-cooled, bipropellant thrust chambers are being used for in-space propulsion. To increase the performance of radiation-cooled engines, improved chamber materials are needed that will allow higher operating conditions (pressure and temperature), better resistance to oxidation, and reduced mass. During this effort, an innovative composite thrust chamber is being developed that will incorporate advanced hafnium oxide and iridium liner techniques as well as replacing the expensive, high-density rhenium with a low-mass carbon-carbon (C–C) structural wall.

Cutting Edge Adhesives for Medical Electronic Devices

TBMG-19329

4/1/2014

Medical electronic devices can run the gamut from imposing MRI and x-ray imaging machines to miniscule implantable circuits designed to detect physical conditions and deliver programmed therapy. As is the case with most electronic gadgets, there is a growing trend in medical electronics toward miniaturization. Advances in circuit miniaturization, low-power architectures, and lightweight components are facilitating improvements to hearing aids, pacemakers, and other devices, while giving rise to promising new applications.