NASA Glenn Research Center
Research & Technology
Materials Highlights - CY 2003
GRCop-84 alloy has been baselined as the main combustion chamber liner alloy in Boeing/Rocketdyne’s RS-84 engine
Improved oxidation resistance of ultra high temperature ceramic (UHTC) materials at 3000°F
Boron nitride nanotubes Boron nitride nanotubes
Dr. Mrityunjay Singh elected as Member (Academician) to the International Academy of Ceramics
Proton Conductivity Test Station
Patents Licensed
GRCop-84 (Copper Alloy) baselined by all rocket propulsion comparisons
Fiber co-mingling developed for reducing cracking in ceramic matrix composites
Recent tests on cooled ceramic matrix composite (CMC) panels
Reduction in Thermal Conductivity for Zirconia-Yttria-based
Thermal Barrier Coatings
Advanced Thermal Barrier Coated Lattice Block Superalloy Tested
Helium permeability of Nanocomposite Tanks
ACS Advances in Materials for Proton Exchange Membrane Fuel Cells Workshop
Mid-infrared (MIR) reflectance as a promising health monitoring tool for TBCs
Porous Ceramic Spheres as Radiation Barriers in Thermal Barrier Coatings
Hybrid Composite Lay-up approach for Carbon Fiber Reinforced Ceramic Composites
Advanced Materials Symposium – Life Sciences – A Third Frontier Forum
Sintering Resistance of Alumina Ceramics Increased Through Incorporation of Carbon Nanotubes
Environmental Durability Branch assisting in Columbia Accident Investigation
QuynhGiao Nguyen receives Distinguished Service Award from Iota Sigma Pi
New low cost, damage tolerant composites for aircraft engine fan containment cases
Lightweight superalloy lattice block material
NASA GRC/COI Ceramics collaboration for commercialization of an advanced silicon carbide fiber
The Materials Division’s High Temperature Mass Spectrometry Research Laboratory
internationally recognized as one of three World Class Laboratories
Glenn Materials Division researchers called upon to assist in the analyses of
Reinforced Carbon-Carbon tiles and deposits from Columbia Accident
A New Shape Memory Alloy
Fabrication of Thick Ceramic Matrix Composite
Advanced, Maintainable Cooled Ceramic Matrix Composite Panel
Space Act Agreement with General Electric Aircraft Engines established
UEET low conductivity thermal barrier coating
Glenn Materials Division researchers assist the NASA Leading-Edge Reinforced Carbon-Carbon (RCC) Deposit Team
A new, efficient method for mapping the temperature distribution inside the heater head of a Stirling Engine
A mathematical model for cyclic oxidation of metals
Data for the thermodynamics of gaseous Si(OH)4
Dr. Kathy Chuang’s ultrahigh temperature polyimide, DMBz-15, selected for a 2003 R&D-100 Award
Meeting with the Directors of NASA University Research Centers
Fabrication of 6”x30” maintainable cooled ceramic matrix composite (CMC) panels
Thermal conductivity of yttria stabilized zirconia (YSZ) ceramic has been increased
A new high temperature turbine disk alloy
A new two-layered nanotube coating
Environmental barrier coatings
The Journal of the American Ceramic Society Special Topic Issue:
High-Temperature Water Vapor Effects
New proton exchange membrane materials for high temperature fuel cells developed
First-ever diamond reinforced copper metal matrix composites
A high temperature oxide ceramic with 100 % strain recovery after creep
Magnetic field-assisted abrasive finishing for polymer matrix composite (PMC) tubes
Advanced nanocomposites could lead to new composite tanks with significantly lower leak rates
Potential collaborations in the development of polymer cross-linked aerogels
A new bimetallic concept for rocket combustion chambers and nozzles
Advanced Shuttle Leading Edge Concept
On-Orbit Repair of Space Shuttle RCC Leading Edge
Ceramic Matrix Composite Turbine Blades
Titanium aluminide (TiAl) scramjet inlet flap concept design and fabrication successfully demonstrated
New multi-component rare earth doped coating material developed
Meeting with Battelle Memorial Institute Researchers
A new molecular sensor has been developed
January 2003
GRCop-84 alloy baselined as main combustion chamber liner alloy in Boeing/Rocketdyne’s RS-84 engine
The advanced copper alloy GRCop-84 has been baselined as the main combustion chamber liner alloy in Boeing/Rocketdyne’s RS-84 engine. This is the primary large rocket engine candidate being developed under the newly reorganized Next Generation Launch Technology (formerly Space Launch Initiative) program. This selection was based, in part, on recent development efforts that have demonstrated that GRCop-84’s mechanical property advantages over the currently used alloy are maintained at the large production scales needed for this engine. This also represents the first application for GRCop-84 in a hydrocarbon-fueled engine. (Point of Contact: 5120/CWRU/David Ellis, 3-8736 and 5120/Michael Nathal.)
Improved oxidation resistance of ultra high temperature ceramic (UHTC) materials at 3000°F
The oxidation resistance of ultra high temperature ceramic (UHTC) materials at of 3000°F has been improved by an order of magnitude by alloying additions. The UHTC material, originally developed at Ames Research Center for application as thermal protection system for space transportation vehicles, consists of a composite of zirconium diboride and silicon carbide. The life of the baseline material is limited to only a few cycles because of severe oxidation problem. Recent results have shown that additions of tantalum-containing compounds to the UHTC material decreases its rate of oxidation by at least a factor of ten, which will enable potential use of this material for hundreds of mission cycles in reusable launch vehicles. This research was supported by 3rd Generation Reusable Launch Vehicle Project. (Point of Contact: 5130/Stan Levine, 3-3276.)
Boron nitride nanotubes
Boron nitride nanotubes have been successfully grown using various processing techniques, which include reactive ball milling and arc discharge. A relatively large quantity (four grams compared to few milligrams for many nanotube processes) of boron nitride nanotubes have been grown in one run using the reactive ball milling process. These nanotubes grown at GRC have been shown to be thermally stable up to 1800°F in air, compared to about 600°F for carbon nanotubes. Potential use of boron nitride nanotubes include reinforcements for metals and ceramics to be used at high temperatures and as electronic materials with more tailorable properties than carbon nanotubes. This research was supported by the CICT Project. (Point of Contact: 5130/Janet Hurst, 3-3286.)
Dr. Mrityunjay Singh elected as Member (Academician) to the International Academy of Ceramics
Dr. Mrityunjay Singh has been elected as Member (Academician) to International Academy of Ceramics, Faenza, Italy. This is one of the most prestigious honors in the field of ceramic science and technology. The academy has about one hundred and eighty members worldwide, with only twenty-three from USA. It has been actively involved in fostering a better understanding of the social involvements and cultural interactions of ceramic science, technology, history, and art. (Point of Contact: 5130/Ajay Misra, 3-8193.)
February 2003
Proton Conductivity Test Station
A new test station has been constructed that is capable of measuring the proton conductivity of polymeric proton exchange membranes for fuel cells (PEM fuel cells). This test apparatus is capable of measuring proton conductivities at room temperature and under varying relative humidity levels. The accuracy of this test station was confirmed by reproducing literature published conductivity values on Nafion 112, the industry standard for use in PEM fuel cells. Proton conductivities of new polymer systems developed in the Polymers Branch are presently being measured. The highest proton conductivity to date was obtained from a new organic/inorganic hybrid polymer, which was slightly higher than that of Nafion 112. Proton conductivity measurements at various relative humidity levels on the new polymer are in progress. In addition to room temperature conductivity measurements, a test cell capable of measuring proton conductivity at elevated temperatures (<200 °C) is under construction. This work is being supported by the Revolutionary Aeropropulsion Concepts project in the Aeropropulsion and Power Base program. (Point of Contact: 5150/Jim Kinder, 3-3149.)
Patents Licensed
Triton Systems, Inc. of Chelmsford, Massachusetts has applied for a commercial license on a group of five GRC patents in high temperature polymers related technologies. Temporary, non-exclusive licenses are being offered on this bundle of five technologies as part of the NASA GRC High Temperature Polymers Marketing Initiative begun in March of 2002 at the GRC/Glitech sponsored High Temperature Polymers Summit. These temporary licenses are designed to enable businesses to survey the market for each of these technologies, identify those which have the most promise for commercialization and develop a business plan around them. At the end of this licensing period, these companies can then opt to license any or all of these patents for further commercialization. This is the second license to result from the High Temperature Polymers Summit. (Point of Contact: 5150/Michael A. Meador, 3-9518.)
GRCop-84 (Copper Alloy) baselined by all rocket propulsion comparisons
GRCop-84 (Copper Alloy) now baselined by all rocket propulsion comparisons. This week, GRCop-84 is the subject of a workshop discussing progress and technology needs for 2nd generation Reusable Launch Vehicles. Team members from Rocketdyne, Aerojet, Pratt & Whitney, NASA Marshall, and several universities will be presenting their research results and technical progress towards the milestones of delivering complete combustion chamber liners ready for testing by the end of this fiscal year. (Point of Contact: 5120/CWRU/David Ellis, 3-8736 and 5120/Michael Nathal, 3-9516.)
Fiber co-mingling developed for reducing cracking in ceramic matrix composites
A novel approach, called fiber co-mingling, has been developed for reducing cracking in ceramic matrix composites (CMCs) for space transportation applications. Carbon fiber reinforced silicon carbide composites are candidate CMC materials for both propulsion and airframe components in reusable launch vehicles. Because of the coefficient of thermal expansion mismatch between carbon fibers and silicon carbide matrix, matrix cracks are developed during cooldown from processing temperature, which limit the life of composite due to rapid ingress of oxidation through the cracks. A hybrid fiber architecture has been developed in which carbon fibers are co-mingled with silicon carbide fibers to reduce coefficient of thermal expansion mismatch between the fiber and the matrix. Initial results have shown significant reduction in cracking in co-mingled fiber composites, as well as introduction of a linear elastic stress-strain response favorable for component design. This research was supported by 3rd Generation Reusable Launch Vehicle Project. (Point of Contact: 5130/Fran Hurwitz, 3-3276; 5920/Anthony Calomino, 3-3311.)
Recent tests on cooled ceramic matrix composite (CMC) panels
Recent tests on cooled ceramic matrix composite (CMC) panels in GRC’s rocket combustion facility have verified heat transfer models and heat exchanger efficiencies in combustion environments typical of space propulsion. Cooled CMC heat exchangers are targeted for use in hot flow path components of reusable launch vehicle propulsion systems. Although heat transfer models existed for predicting heat exchanger efficiencies in cooled CMC structures, they were not verified in realistic environments representing space propulsion conditions. Several heavily instrumented 2 ½” x 10” cooled CMC panels of two different designs were tested under rocket combustion conditions with hydrogen and oxygen fuel, and heat flux measured at several locations. The measured heat flux compared reasonably well with the values predicted from models. The verified models were used to improve one of the cooled CMC panel designs. This research was supported by 3rd Generation Reusable Launch Vehicle Project. (Point of Contact: 5130/Martha Jaskowiak, 3-5515; 5830/Kevin Dickens, 3- 6491.)
Reduction in Thermal Conductivity for Zirconia-Yttria-based Thermal Barrier Coatings
Addition of multi-component rare earth dopants to zirconia-yttria-based thermal barrier coatings (TBC) has been shown to reduce the thermal conductivity of the TBC by a factor of 2-3. This represents a key factor in extending TBC protection to much higher gas temperatures in turbine engines. Defect clusters, induced in the zirconia-yttria-based TBC structure by the addition of the dopants, were identified using transmission electron microscopy (TEM). The TEM lattice imaging, selected area diffraction (SAD) and electron energy loss spectroscopy (EELS) analyses demonstrated that the extensive nanoscale rare earth dopant segregation exists in both the plasma-sprayed and electron-physical-vapor-deposited thermal barrier coatings, which facilitates the formation of parallel and rotational defective lattice clusters. The presence of the 5 to 100 nm sized defect clusters and nanophases are responsible for the significant reduction of thermal conductivity, improved sintering resistance and long-term high temperature stability of the advanced thermal barrier coating systems. This work is supported by UEET Program Office. (Point of Contact: 5160/Dr. Dongming Zhu, 3-5422; QSS/5120/Dr. Yuan L. Chen, 3-8905; and 5160/Dr. Robert A. Miller, 3-3298)
Advanced Thermal Barrier Coated Lattice Block Superalloy Tested
An advanced thermal barrier coated superalloy (MAR-M-247), produced in the form of a light-weight lattice block structure, was exposed in a Mach 0.3 Burner Rig for over 800 hours at 2100° F and 5 ksi tensile stress with no signs of failure. The sample was gripped on both ends and held at a constant stress while the face was heated perpendicular to the burner flow to 2100° F. This material is a cast superalloy, possessing a bridge-like structure with a TBC-coated face sheet on one side and a 30% reduced density material and is being evaluated for possible turbine engine applications, such as in the exhaust section and/or as a containment structure. In addition to its light weight and high temperature durability, the open structure of the back-side of the lattice block (which runs 140°F cooler than the front-side with no active cooling air) could be filled with an acoustic treatment for reducing cabin and ground noise effects. The block has been tested to failure under higher tensile stresses of 8 and 10 ksi and lasted nearly 500 hours at each condition. This work is being funded by the Ultra-Efficient Engine Technology Project. (Point of Contact: OAI/5120/Mohan Hebsur, 3-3266 and QSS/5160/Michael Cuy, 3-3159)
March 2003
Helium permeability of Nanocomposite Tanks
The helium permeability of GRC developed carbon fiber reinforced nanocomposite tanks is being tested by TRW. These tanks were fabricated by Rocky Mountain Composites using a low-cost filament winding process. They were hydrostatically tested to 200 psi and nitrogen leak tested to 70 psi. Previous work at GRC has demonstrated that these nanocomposites have substantially lower hydrogen and oxygen permeability than typical composite materials. TRW is interested in these nanocomposites for potential use in lightweight propellant storage tanks and is testing the filament wound tanks at no cost to NASA. (Point of Contact: 5150/Dr. James C. Johnston, 3-5029)
ACS Advances in Materials for Proton Exchange Membrane Fuel Cells Workshop
Jim Kinder, Kathy Chuang, Amy Jo Sanders, Mike Meador and Mary Ann Meador attended the American Chemical Society’s Advances in Materials for Proton Exchange Membrane Fuel Cells Workshop held in Pacific Grove, CA from February 23-26, 2003. This meeting, which reviewed technology needs and recent developments in PEM fuel cell materials research, was heavily attended by Government, university and industry researchers. Discussions were held with representatives from several companies pursuing the development of fuel cells for automotive and personal electronics applications about potential collaborations to develop and evaluated GRC developed membrane materials for their applications. Follow-on discussions will be held with some of these companies to pursue these collaborations. (Point of Contact: 5150/Dr. James D. Kinder 3-3149)
Mid-infrared (MIR) reflectance as a promising health monitoring tool for TBCs
The risk of thermal barrier coating (TBC) failure on turbine engine components currently restricts their application by either forcing extreme safety margins for coating replacement or by limiting coating applications to engine temperatures where the underlying component can still survive. Mid-infrared (MIR) reflectance has been demonstrated in the laboratory as a promising health monitoring tool for TBCs. A reliable correlation was established between the progression of delamination cracks along the bottom of the TBC and the increase in MIR reflectance of TBC-coated specimens. This technique is a very promising approach for practical TBC health monitoring between-flight inspections to determine the fraction of TBC lifetime remaining. This work was funded by the Director’s Discretionary Funds with supporting funds from the Ultra-Efficient Engine Technology Project. (Point of Contact: 5160/Dr. Jeffrey Eldridge, 3-6074 and 5920/Richard Martin, 3-3684)
Porous Ceramic Spheres as Radiation Barriers in Thermal Barrier Coatings
A process has been developed to create porous ceramic spheres for potential application as radiation barriers in advanced thermal barrier coatings. One concept for improving coating effectiveness at temperatures on the order of 3000oF is to incorporate a porous ceramic layer in the coating that acts as a radiation barrier by reflecting or scattering photon radiation. Fabrication of the porous ceramic with an engineered microstructure suitable for radiation scattering is a major challenge. A templating process using a polystyrene base cation exchange resin has been developed to produce porous zirconia ceramic spheres with 0.5 to 2 micron internal pores, which are in the desired size range for efficient scattering of visible and infrared radiation. A bonding technique is currently being developed to incorporate porous ceramic spheres in thermal barrier coatings. The research was supported by the Ultra Efficient Engine Technology Program. (Point of Contact: 5130/Fred Dynys, 3-2404)
Hybrid Composite Lay-up approach for Carbon Fiber Reinforced Ceramic Composites
A hybrid composite lay-up approach has improved durability of carbon fiber reinforced silicon carbide (C/SiC) ceramic composites by nearly an order of magnitude. The C/SiC composites are candidate materials for use in hot flowpath components in advanced space transportation system. The hybrid composite consist of stacked plies of woven carbon and silicon carbide fiber, which takes advantage of the extremely high creep resistance of the carbon fibers and superior oxidation resistance of the silicon carbide fibers. The life of the hybrid composite at 2650oF under 10 ksi loading is about 40 hr, which is an order of magnitude higher than the baseline C/SiC composite. This research was supported by 3rd Generation Reusable Launch Vehicle Project. (Point of Contact: 5130/Jay Singh, 3-8883; Greg Morscher, 3-5512)
April 2003
Advanced Materials Symposium – Life Sciences – A Third Frontier Forum
Michael Meador was the Featured Technology Speaker for Ohio Polymer Enterprise Development (OPED) Corporations’s Advanced Materials Symposium – Life Sciences- A Third Frontier Forum held at the University of Akron on March 21. This symposium had 200 attendees and was the first in a series put together by OPED to feature technologies developed in Ohio-based universities, industry, and Federal laboratories that have high potential for commercialization. OPED is planning additional symposia featuring such topics as nanotechnology, fuel cells, and sensors. Dr. Meador presented an overview of three GRC developed technologies (ultraviolet light curable polymers, charge transfer molecular sensors, polymer electrolytes for lithium polymer batteries) with potential biomedical/life sciences applications. (Point of Contact: 5150/Michael A. Meador, 3-9518)
Sintering Resistance of Alumina Ceramics Increased Through Incorporation of Carbon Nanotubes
The sintering resistance of alumina ceramics has been increased by an order of magnitude through incorporation of carbon nanotubes. One of the factors that limit the high temperature capability of ceramic materials is sintering due to grain growth. The grain size of alumina ceramic after exposure at 2650oF was decreased by an order of magnitude by addition of 5 weight percent carbon nanotube. These preliminary results indicate that addition of nanotubes to ceramic materials offers the potential for significant increase in temperature capability of such materials. This research was supported by the Ultra Efficient Engine Technology Program. (Point of Contact: 5130/Janet Hurst, 3-3286)
Environmental Durability Branch assisting in Columbia Accident Investigation
The Environmental Durability Branch’s high temperature chemistry and metallurgy experts have been called upon to join with NASA scientists from MSFS, KSC, JSC and LaRC to investigate the role of the left wing leading edge material in the Space Shuttle Columbia’s (OV-102) accident. The leading edge evaluation team is lead by Dr. Sandeep Shah from MSFC and reports directly to the Columbia Accident Investigation Board. Work is focused upon the evaluation of “slag deposits,” collected from both wings leading edge reinforced carbon-carbon panels, to provide concrete evidence of the location and impact of the suspected breech location. Early microstructural and chemical characterization indicate that the deposit is a complex mixture of the leading edge and surrounding structural materials of the orbiter. GRC is analyzing the deposits, looking for indications of phase formation, particulate chemistries, etc. to help determine at what altitude, temperature and sequence the leading edge and nearby structural component materials were lost during the Columbia descent. The Microstructural Characterization Laboratory (5120) and the Surface Science Branch (5960) are augmenting the GRC effort via x-ray diffraction, microprobe and x-ray photoelectron spectroscopy analyses. Earlier in the week Dr. Nathan Jacobson visited KSC to present our results to date and to explore the collection of crash debris which may help to provide further insight and potentially new clues to aid our work. This effort is being coordinated with the Space Transportation Office. (Point of Contact: 5160/Dr. Nathan Jacobson, 3-5498, Dr. James Smialek, 3-5500, and Dr. Elizabeth Opila, 3-8904)
QuynhGiao Nguyen receives Distinguished Service Award from Iota Sigma Pi
QuynhGiao Nguyen has received the Fluorine Chapter Joan Lambros Distinguished Service Award from Iota Sigma Pi, the National Honor Society for Women in Chemistry on April 10, 2003. Iota Sigma Pi is an organization within the American Chemical Society. She has been a member of the Society since 1995 induction. She serves on Chemistry Scholarship Review Committee and currently represents the local chapter as a National Council Member. (Point of Contact: 5160/Leslie A. Greenbauer-Seng, 3-6781)
New low cost, damage tolerant composites for aircraft engine fan containment cases
New low cost, damage tolerant composites have been evaluated for use in aircraft engine fan containment cases. These composites were made using automated 3D braiding of preforms with integral stiffeners, a low cost T700 carbon fiber, and a low cost resin infusion process. Preforms were braided by A&P Technology, composites were fabricated by GEAE, and impact tests were performed in the Ballistic Impact Lab at GRC. The penetration threshold for the new materials was over twice that of materials previously evaluated by GEAE. Damage in the form of cracks and delamination extending far beyond the impact site was a major problem with earlier composite materials. These damage modes were eliminated using the new braided composite materials. As a result of the improved material performance and the demonstrated approach to low cost manufacturing, GEAE has initiated efforts to apply this technology to next generation commercial engines. This work was supported by the Ultrasafe program. Point of Contact: Dr. Gary D. Roberts, 5150, 3-3244, Gary.D.Roberts@nasa.gov.
May 2003
Lightweight superalloy lattice block material
An assessment performed by GE Aircraft Engines concluded that significant benefits can result from the use of lightweight superalloy lattice block material. Prior NASA work demonstrated the feasibility of lattice block superalloys for use in engines at temperatures up to 2000°F. This work attracted GE to an in-depth study on several potential components, which included structural capability, producability, and weight savings potential. Feasible applications identified by the study include exhaust nozzle, duct, case, liner and strut components, with projected weight reductions reaching 30%. This work was funded by the UEET program. (Point of Contact: 5120/ J. Daniel Whittenberger, 3-3196)
NASA GRC/COI Ceramics collaboration for commercialization of an advanced silicon carbide fiber
NASA GRC is collaborating with COI Ceramics to commercialize an advanced silicon carbide fiber. The fiber was developed in the High Speed Research Program through joint research between NASA and Dow Corning, and is the best silicon carbide fiber in the world today in terms of high temperature capability and environmental durability. COI Ceramics, through a license from Dow Corning and funding from the Air Force, will establish the fiber production process. NASA GRC will support COI Ceramics in establishing the performance quality of the new fiber by performing specialized fiber characterization tests. In addition, GRC will transfer the NASA-developed fiber treatment process for incorporation in COI’s production line. The collaboration is critical for ensuring availability of the advanced silicon carbide fiber for the Ultra Efficient Engine Technology and Next Generation Launch Technology Programs. This research was supported by the Ultra Efficient Engine Technology Program. (Point of Contact: 5130/Jim DiCarlo, 3-5514)
The Materials Division’s High Temperature Mass Spectrometry Research Laboratory internationally recognized as one of three World Class Laboratories
The Materials Division’s High Temperature Mass Spectrometry Research Laboratory has been internationally recognized as only one of three World Class Laboratories. Mass Spectrometry is an important experimental technique for evaluating and predicting material high temperature behavior and performance in component propulsion and power application environments. Maintaining isothermal conditions and reliable absolute temperature measurements are the major experimental difficulties encountered in thermodynamic property measurements. Recent design of a multi-cell effusion configuration and the implementation of a new temperature measurement technique have enabled a higher level of accuracy and reproducibility in experimental of absolute temperature measurement. The measurements of the melting point of gold (1337.58 K) and the second law calculation of the enthalpy of reaction (DHsubAu(298.15) (367.0±2.0 kJ/mol) provides a primary temperature standard that can be calibrated in situ during each experimental run. (Point of Contact: 5160/CWRU/Evan Copland, 3-3738)
June 2003
GRC Materials Division providing critical chemical, microstructural and failure analyses information in support of the Space Shuttle Columbia accident investigations
High temperature material behavior and reaction chemistry and carbon-carbon composites expertise at Glenn is providing critical chemical, microstructural and failure analyses information in support of the Space Shuttle Columbia accident investigations. The Materials Division has two members supporting the LESS Reinforced Carbon-Carbon (RCC) WLE Aging Effects Sub-Team formed as a result of the Columbia accident. Our researchers are conducting scanning electron microscopy studies of leading edge Reinforced Carbon-Carbon (RCC) shuttle tiles which have experienced several launches/reentries, however, not aboard Columbia. Early results have been presented to upper level technical/management individuals at MSFC, KSC, and JSC associated with the NASA Accident Investigation Team, as well as members of the Columbia Accident Investigation Board. The effort will be contributing insight into tile lifetime as additional studies of newly manufactured tiles are obtained. In addition, these Glenn researchers are also participating in the failure analysis studies of Columbia vehicle debris within the Kennedy Debris Analysis Working Group, Shuttle Return-to-Flight Team. (Contact: 5130/Dr. Anthony Calomino, 3-3311 and 5130/Dr. Frances Hurwitz 3-5503)
Glenn Materials Division researchers called upon to assist in the analyses of Reinforced Carbon-Carbon tiles and deposits from Columbia Accident
The NASA Leading-Edge Reinforced Carbon-Carbon (RCC) Deposit Team was formed to investigate the unusual “slag” deposits found on leading edge tiles recovered from Columbia accident. Deposits with very complex chemistries were found on the internal surfaces of the recovered portions of many of the leading edge panels, but were found to be particularly heavy on the left wing Panel 8 and Panel 9. Glenn Materials Division researchers were called upon to assist in the analyses of the RCC tiles and deposits because of their familiarity and previous research experience studying the shuttle’s RCC leading edge materials. Analyses of approximately 30 sampled specimens taken from the left wing leading edge of RCC Panels 8 and 9 have been performed using scanning electron microscopy, microprobe, x-ray diffraction and x-ray photoelectron spectroscopy. Radiography, microprobe and electron dot mapping analyses were also conducted at Langley, Marshall and Kennedy, respectively. The team which includes experts from Glenn, Marshall, Johnson and Langley centers met for an extensive technical review of all analysis data acquired from the deposits on RCC Panel 8, at Kennedy in mid-May. The deposit chemistries and microstructures, combined with radiography of Panel 8 enabled a hypothesis, consistent with other discipline group findings, to be formed as to a likely breach location and the flow directions of the hot gases which entered into the leading edge panels. The results of Panel 8 analyses were presented to the NASA Accident Investigation and to the Columbia Accident Investigations Boards on May 17, 2003. Glenn and Marshall have completed the analyses of Panel 9 deposit specimens. The full team reviewed and evaluated Panel 9 data on June 4, 2003. A final presentation of the results and conclusions concerning the RCC Panel 9 leading-edge RCC deposit study will be presented to the CAIB within the next week. (Contact: 5160/Dr. Nathan S. Jacobson, 3-5498 and 5160/Leslie A. Greenbauer-Seng, 3-6781)
A New Shape Memory Alloy
A new Shape Memory Alloy designed to operate at temperatures up to 500oC was successfully demonstrated. Shape memory alloys have the unusual ability to be deformed at a low temperature and return to their original shape after heating. These alloys are one of the main classes of “smart materials” that are intended for use in morphing or intelligent systems. Current alloys are limited to ~250oC, which limits their application within a turbine engine. The feasibility of the new alloy was demonstrated by measuring high temperature actuation temperature, good ductility, and good environmental durability. This work was funded by the RAC project. (Point of Contact: 5120/ M. V. Nathal, 3-9516, 5120/U. of Toledo/Anita Garg,, 5120/Ron Noebe, and 5120/Tiffany Biles)
Fabrication of Thick Ceramic Matrix Composite
For the first time, it has been demonstrated that a thick ceramic matrix composite (CMC), representing the root section of a turbine blade, can be fabricated with desired mechanical properties. The thickness of current sate-of-the-art woven CMC structures, developed for combustor liners, is typically 0. 08”, compared to the required thickness in the range of 0.25” to 1” for the root section of a turbine blade. Recently, GRC researchers have successfully fabricated silicon carbide fiber reinforced silicon carbide CMCs with thicknesses in the range of 0.34” to 0.42”. The mechanical properties, including strength and stress rupture life, of these thick CMCs are better than the comparable thin CMC structures with the same constituents. These results have shown the feasibility of fabrication of the root section of a CMC turbine blade. This research was supported by the Next Generation Launch Technology Program. (Point of Contact: 5130/Jay Singh, 3-8883; OAI/Greg Morscher, 3-5512, 5130/Marc Freedman, 3-3284)
Advanced, Maintainable Cooled Ceramic Matrix Composite Panel
An advanced, maintainable cooled ceramic matrix composite (CMC) panel concept has been successfully tested in GRC’s rocket combustion facility (Cell 22) for a total time of eighteen minutes, which is the longest time tested so far in NASA’s NGLT program. Cooled ceramic heat exchangers are targeted for use in hot flow path components of reusable launch vehicle propulsion systems. The maintainable panel concept uses an innovative high temperature ceramic fastener design that enables mechanical attachment of the cooled panel to the rest of the structure for easy removal of individual panels for repair and replacement. The recent tests have demonstrated, for the first time, the performance and durability of these panels for a total duration of 18 minutes under rocket combustion conditions at maximum hot surface temperature of 2600oF. This research was supported by the Next Generation Launch Technology Program. (Point of Contact: 5130/Martha Jaskowiak, 3-5515, 5830/Kevin Dickens, 3-6491)
Space Act Agreement with General Electric Aircraft Engines established
A Space Act Agreement with General Electric Aircraft Engines (GEAE) has been recently established and approved. The objective of the agreement is to provide GEAE the Rare Earth Silicate Environmental Barrier Coatings (EBC), developed at NASA Glenn Research Center under the Ultra Efficient Technology Project, for their evaluation. GEAE will perform environmental durability testing, cost assessment, and coating manufacturability evaluation of the coating. NASA will provide EBC-coated SiC-reinforced SiC composite specimens for rig testing under flame jet and combined hot corrosion/oxidation conditions at GEAE, free-standing bulk EBC samples for volatilization testing, EBC processing parameters, and Rare Earth Silicate EBC data generated at NASA. The work performed here has the potential to become the pathway for commercialization of NASA developed technology. (Point of Contact: 5160/Dr. Kang N. Lee, 3-3298)
UEET low conductivity thermal barrier coating
The UEET low conductivity thermal barrier coating (UEET low k TBC) is being developed and deposited by electron beam physical vapor deposition, for single crystal superalloy turbine blade applications and by ambient plasma spraying, for combustor applications. A notable recent laboratory accomplishment has been the successful laser-rig testing of a UEET low k TBC on a metallic superalloy substrate at a very high TBC surface temperature of 3000°F. This early result gives the engine company designers the confidence to consider the possibility of using TBC-coated metallic substrates for applications that may have otherwise required a ceramic matrix composite. The availability of a very high temperature capable TBC could also be very beneficial to a Turbine Based Combined Cycle augmentor application. The work has been funded under the Ultra-Efficient Engine Technology (UEET) Program Office. (Points of Contact: 0300/Dongming Zhu, 3-5422; and 5160/Robert A. Miller, 3-3298)
Glenn Materials Division researchers assist the NASA Leading-Edge Reinforced Carbon-Carbon (RCC) Deposit Team
The NASA Leading-Edge Reinforced Carbon-Carbon (RCC) Deposit Team, formed to investigate the unusual “slag” deposits found on leading edge tiles recovered from Columbia accident, asked Glenn Materials Division researchers to assist in the analyses of the RCC tiles and deposits. The deposits, with very complex chemistries, were found on the internal surfaces of recovered portions of many of the leading edge panels, but seemed to be particularly heavy on the Shuttle’s left wing Panel 8 and Panel 9. Glenn researchers characterized over 40 specimens taken from Columbia’s left wing leading edge of RCC Panels 8 and 9 which had been recovered. Scanning electron microscopy, microprobe, x-ray diffraction and x-ray photoelectron spectroscopy data from Glenn, along with radiography, microbe and electron dot mapping analyses from Langley, Marshall, Kennedy and Johnson was used for the chemical assessment of the “slag” deposits. The deposit chemistries and microstructures, combined with radiography of Panel 8 and 9, enabled the team to develop a plausible scenario for the RCC panel breach and hot gas flow path into the leading edge of the left wing. The scenario proved to be consistent with other discipline working groups’ assessment of the accident. Results of the team findings have been presented to NASA and Columbia Accident Investigation Boards and have been discussed in a number of media publications. (Point of Contact: 5160/Dr. Nathan S. Jacobson, 3-5498 and 5160/Leslie A. Greenbauer-Seng, 3-6781)
July 2003
A new, efficient method for mapping the temperature distribution inside the heater head of a Stirling Engine
A new, efficient method for mapping the temperature distribution inside the heater head of a Stirling Engine was developed and calibrated. During operation, the heater head is inaccessible to conventional temperature sensors. A method was devised to infer the temperature distribution by noting the color variations in the heater head due to oxidation. This was accomplished by exposing samples of the alloy (IN718) to various times and temperatures, documenting the resulting color of the samples, and then measuring the resulting oxide thickness. Using oxide growth equations for superalloys it was then possible, based on the color of the component, to accurately estimate either the exposure temperature or exposure time. As an unexpected benefit, emissivity (another important parameter to the Stirling engine) could also be accurately estimated from the sample color. This data was generated for air, 4 ppm O2, and vacuum environments. This data was applied to actual heater heads subjected to extensive testing, and will be used to optimize the design of the Stirling system. This work was funded by the Stirling Radioisotope Generator Task of Project Prometheus. (Point of Contact: 5120/ Randy Bowman 3-3205)
A mathematical model for cyclic oxidation of metals
A mathematical model for cyclic oxidation of metals has been developed. Over the past 25 years various models have been proposed to account for the incremental, step-wise weight changes that occur during the cyclic oxidation scale growth and spallation (protective scale loss) processes that degrade materials in high temperature engine applications. Simple algebraic expressions for the characteristic features of cyclic oxidation have been derived as functions of the input variables. The mathematical simplicity of this approach has led to the concept of a universal cyclic oxidation curve. For example, multiple cyclic curves for an alloy oxidized at different temperatures or with different reactive element contents can all be represented by a single plot. Similarly, a universal material consumption kinetic curve and a universal failure map have been constructed as aids to life prediction. This research is supported by Aeropropulsion and Power Program. (Point of Contact: 5100/Dr. James Smialek, 3-5500).
Data for the thermodynamics of gaseous Si(OH)4
Volatilization of silicon-based ceramics and composites is enhanced in the presence of water vapor combustion products. Accurate thermodynamic data is required as an input to predictive models developed at GRC. To date, a comprehensive series of experiments have yielded reliable data for the thermodynamics of the gaseous Si(OH)4. These data are consistent with both other experimental and theoretical studies. Current work focuses on gaseous SiO(OH)2, which is important at higher temperatures. This research is being supported by HOT PC/Computational Thermodynamics. (Point of Contact: 5160/N. Jacobson, 3-5498 and CSU/E. Opila, 3-8904)
Dr. Kathy Chuang’s ultrahigh temperature polyimide, DMBz-15, selected for a 2003 R&D-100 Award
Dr. Kathy Chuang has been notified by R&D magazine that her ultrahigh temperature polyimide, DMBz-15, has been selected for a 2003 R&D-100 Award. This new polyimide enables the development of fiber reinforced polymer matrix composites with use temperatures as high as 650°F – an increase of more than 100°F above the state-of-the-art high temperature composites. Potential applications for this award winning material include components for commercial and military aircraft engines, space transporation propulsion systems, missiles, and hot airframe structures in military aircraft. This award nomination was submitted jointly by NASA Glenn and the Maverick Corporation of Blue Ash, Ohio. Maverick Corporation and Triton Systems, Incorporated have licensed this GRC developed material. (Point of Contact: 5150/Dr. Kathy Chuang, 3-3227)
Meeting with the Directors of NASA University Research Centers
A meeting of Directors and NASA Technical Review Committee Chairs for the NASA (Code N) University Research Centers and representatives from the NASA HQ Minority University Research and Education Programs Office was held in Orlando, Florida on July 19th. The purpose of this meeting was to acquaint the new Group 3 URC Directors with issues and procedures in managing these Research Centers and discuss ways in which the Technical Review Committees, the University Research Centers and Code N can work together to ensure their success. Robert Lawrence (9000), Felix Miranda (5640) and Michael Meador (5150) participated in this meeting. Dr. Miranda is the TRC Chair for the Center for Nanomaterials Research, CNMR, at the University of Puerto Rico and Dr. Meador is the Chair of the Center for High Performance Polymers and Composites, HiPPAC, at Clark Atlanta University. The HiPPAC Center at Clark Atlanta University was one of the original (Group 1) URCs and one of only two of this group to be selected for a new (Group 3) award. (Point of Contact: 5150/Dr. Michael A. Meador, 3-9518)
August 2003
Fabrication of 6”x30” maintainable cooled ceramic matrix composite (CMC) panels
Manufacturing process has successfully been scaled up to fabricate 6”x30” maintainable cooled ceramic matrix composite (CMC) panels as part of a joint GRC/Pratt & Whitney program. Cooled ceramic heat exchangers are targeted for use in hot flow path components of reusable launch vehicle propulsion systems. The maintainable cooled panel design was demonstrated earlier in a series of tests with 2 ½” x 10” panels in GRC’s Research Combustion Laboratory. The next challenge was to fabricate larger panels, 6”x30” size, for scramjet engine testing. Large panels have now been fabricated without visible defects, and are being instrumented for scramjet engine testing at United Technologies Research Center in October 2003. This research was supported by the Next Generation Launch Technology Program. (Point of Contact: 5130/Martha Jaskowiak, 3-5515)
Thermal conductivity of yttria stabilized zirconia (YSZ) ceramic has been increased
Thermal conductivity of yttria stabilized zirconia (YSZ) ceramic has been increased by 50 % for application as interconnect support materials in solid oxide fuel cell (SOFC) systems. The YSZ ceramic is used as a support structure for current collector interconnects in some SOFC stack designs. A high thermal conductivity of YSZ is required for increasing heat transfer effectiveness in the SOFC stack. It has been shown that addition of alumina to YSZ ceramic can increase its thermal conductivity by 50 %, while at the same time increasing its strength and fracture toughness. This knowledge will be transferred to SOFCo-EFS Holding, a SOFC development manufacturing company located in Alliance, Ohio, for potential incorporation in their stack design. This research was supported by the RAC HOTPC project of the Aerospace Propulsion and Power Program. (Point of Contact: 5130/Narottam Bansal, 3-3855; 5160/Dongming Zhu, 3-5422)
A new high temperature turbine disk alloy
A new high temperature turbine disk alloy has been developed that makes another large step towards the “holy grail” of 1500oF capability. The previous best alloys, known as ME3 and Alloy 10, were developed and scaled-up in the High Speed Research and Advanced Subsonics programs for applications up to 1250oF, and are scheduled for introduction in commercial and military engines in the next few years. The new NASA alloy increases the temperature capability to 14000F, combined with excellent processing/property versatility. This versatility allows the alloy to meet requirements for small, strength-limited disks needed for business and regional commercial jet engines; as well as large, creep and crack growth-limited disks of very large engines needed for advanced commercial and Next Generation Launch Technology vehicles. The alloy was invented and verified in subscale quantities in the HOTPC project of the Aeropropulsion and Power Program. It is now being further assessed in the Aviation Safety Program, using mechanical property and spin tests of large scale disks. (Point of Contact: 5120/ Tim Gabb, 3-3272; 5120/John Gayda; 5920/ Pete Kantzos; and 5920/Jack Telesman)
A new two-layered nanotube coating
A new two-layered nanotube coating (nanotube topcoat/iron bondcoat/quartz substrate) with superior friction properties in air and in ultrahigh vacuum, a space-like environment, has been developed for aerospace applications, including the development of micro-machines. These systems have contacting surfaces in relative motion. Friction influences performance, energy consumption, wear damage, maintenance, short lives or catastrophic failure, and reliability of the mechanical systems. The coefficient of friction for the new nanotube coating in contact with 440C stainless steel is one fourth of that for quartz or iron coating on quartz in air. The coating can dramatically decrease friction of the contacting surfaces, a major issue for micro-machines. This research was supported by the HOTPC and RAC efforts of the Propulsion and Power Project. (Point of Contact: 5160/Dr. Kazuhisa Miyoshi, 3-6078; 6711/Dr. Randy Vander Wal; 5130/ Drs. Ali Sayir and Serene Farmer)
Environmental barrier coatings
Environmental barrier coatings (EBC) developed in the Ultra Efficient Engine Technology (UEET) Project have been applied by plasma spraying the coating on melt-infiltrated silicon carbide/silicon carbide vanes and other components for durability testing. A new intermediate coating that has been under development in the UEET Project provides enhanced adherence, enabling the application of EBCs by conventional plasma spraying, a great advantage for the technology be transferred to and used by industry. (Point of Contact: 5160/Dr. Kang Lee, 3-5634)
The Journal of the American Ceramic Society Special Topic Issue: High-Temperature Water Vapor Effects
The Journal of the American Ceramic Society has just released a Special Topic Issue: High-Temperature Water Vapor Effects as the August 2003 (Vol. 86, No. 8) publication. Dr. Elizabeth Opila was invited to write the introduction for the journal because of her international reputation in water vapor interactions in silicon-based ceramics studies. Four papers were contributed by the Environmental Durability Branch members in the areas of oxidation and volatilization of silica forming materials in water vapor environments (e.g. combustion environment) and in upper temperature capability of environmental barrier coatings, which are used to suppress the volatilization reactions. This work was funded by the Ultra-Efficient Engine Technology Project. (Contact: 5160/Dr. Elizabeth J. Opila, 3-8904)
New proton exchange membrane materials for high temperature fuel cells developed
New proton exchange membrane materials for high temperature fuel cells have been developed with good proton conductivity at 120°C and low humidity (25% relative humidity) – more than ten times that of the state of the art! Nafion, the most widely used fuel cell membrane material, is unsuitable for use at high temperatures since it “dries out” and looses proton conductivity. Two new polymer systems have been developed at GRC that have significantly higher proton conductivity than Nafion 117 at 120 °C and at 25% relative humidity. Proton conductivities for these materials are as high as 3.1x10-3 S/cm , more than an order of magnitude higher than Nafion 117 under the same test conditions. Under the same test conditions, the proton conductivity of Nafion 117 was too low to be measured. (Point of Contact: 5150/Dr. James Kinder, 3-3149)
First-ever diamond reinforced copper metal matrix composites
The first-ever diamond reinforced copper metal matrix composites were recently produced. Diamond/copper composites can provide both higher conductivity combined with high strength and lighter weight, all desirable criteria for high heat flux applications in space transportation propulsion systems. Both cast and powder metallurgy composites with diamond contents ranging from 20-50 volume percent have been made and characterized. The composites show good microstructures and encouraging mechanical properties such as strength and ductility. This work was funded by the Propulsion Research and Technology Project of the Next Generation Launch Technology Program. (Point of Contact: 5120/ David Ellis, 3-8736 and 5120/Michael Nathal, 3-9516)/
September 2003
A high temperature oxide ceramic with 100 % strain recovery after creep
A high temperature oxide ceramic with 100 % strain recovery after creep at temperatures as high as 2552oF has been developed. Typically, creep of ceramic materials at high temperature results in permanent deformation of the material. A new oxide ceramic material system consisting of a mixture of alumina and erbium aluminum garnet, grown from the melt in GRC’s state-of-the-art laser float zone crystal growth capability, exhibits 100 % strain recovery after creep at 2552oF under a load of 50 ksi. This is the first time that 100 % strain recovery after creep deformation has been observed for any ceramic material. The new material system can find many potential applications, which include high temperature blade materials, shape memory ceramics and self healing materials for smart structures. The research was supported by the HOTPC project of the Aerospace Propulsion and Power Program. (Point of Contact: 5130/ CWRU/Ali Sayir, 3-6254 and 5130/Serene Farmer, 3-3289)
Magnetic field-assisted abrasive finishing for polymer matrix composite (PMC) tubes
Dr. Hitomi Yamaguchi from the Faculty of Engineering, Utsunomiya University in Tochigi, Japan, recently completed a one-year sabbatical in the Materials Division. Dr. Yamaguchi was hosted by Dr. Kazuhisa Miyoshi and performed research into the applicability of magnetic field-assisted abrasive finishing for polymer matrix composite (PMC) tubes. This is an important issue for piping systems, found in both turbine and rocket engine applications. Stress concentrations result from unevenness of the internal surfaces and may cause turbulence and cavitations in the fluids during operation resulting in damage and contamination. Experiments demonstrated the feasibility of this technique to finish not only carbon-reinforced PMC’s, but also ceramic deposited coatings on the PMC surface as well. Funding for this work was provided by the Propulsion & Power Program (HOTPC Project). (Point of Contact: 5160/Leslie A. Greenbauer-Seng, 3-6781 and 5160/Kazuhisa Miyoshi, 3-6078)
Advanced nanocomposites could lead to new composite tanks with significantly lower leak rates
Advanced nanocomposites have recently been developed that could lead to new composite tanks with significantly lower leak rates. Helium leak testing was performed under a Space Act Agreement with TRW on filament wound lightweight gas storage tanks made with a conventional epoxy and a epoxy/clay nanocomposite. The nanocomposite tank had a five-fold lower helium leak rate at room temperature than the tank made from the conventional epoxy! These results indicate that epoxy/clay nancomposites can be also be used in lightweight hydrogen storage tanks for hydrogen powered aircraft, UAVs, and reusable launch vehicles. This work has been supported by the Vehicle Systems Project. (Point of Contact: 5150/Dr. Chris Johnston, 3-5029)
Potential collaborations in the development of polymer cross-linked aerogels
Nick Leventis visited JPL on August 12th to present his work on polymer cross-linked aerogels and discuss potential collaborations in the development of these materials. As a result of this meeting, JPL has agreed to furnish some of their carbon fiber reinforced aerogels to GRC to determine if polymer cross-linking can be used to improve their properties and durability. (Point of Contact: 5150/Dr. Nick Leventis, 3-3202)
A new bimetallic concept for rocket combustion chambers and nozzles
A new bimetallic concept for rocket combustion chambers and nozzles was demonstrated to survive high levels of thermal shock. Nickel aluminide (NiAl) is one of the best materials in terms of high temperature strength and thermal conductivity, combined with low density and excellent resistance to environmental attack. However, it is prone to brittle fracture at low temperatures. The bimetallic concept where an inner layer of NiAl is encased by an outer layer of either a nickel-base superalloy or a copper alloy provides both thermal and structural performance. Bimetallic nozzles have been fabricated and tested in a high heat flux environment, and have survived multiple cycles without any signs of degradation. This also represents the inaugural use of the new Quick Access Rocket Environment (QARE) Rig designed to screen materials prior to testing in the higher pressure facilities available in the Research Combustion Laboratory test cells. This work was funded by the High Conductivity Materials Task of the NGLT Propulsion Research and Technology Project. (Point of Contact: 5120/ John Gayda, 3-3273, and 5120/Michael Nathal)
October 2003
Advanced Shuttle Leading Edge Concept
An advanced Shuttle leading edge concept consisting of a sandwich structure with ceramic matrix composite (CMC) face sheets survived the ballistic impact test without damage to the outer silicon carbide CMC structure. The current state-of-the-art reinforced C/C composite leading edge material used in the space shuttle has limited life due to oxidative degradation of carbon fiber and damage under severe impact conditions. An alternate leading edge concept has been developed at GRC in which an insulating core is sandwiched between two silicon carbide fiber reinforced silicon carbide CMC face sheets. The sandwich structure utilizes load sharing between two CMC face sheets, thus offering the potential for improving reliability and safety by eliminating prime reliance on any one element. As demonstration of the improved safety of this concept, a foam projectile having a kinetic energy 30 percent greater than that required to fail current reinforced carbon-carbon material. The new leading edge concept survived the impact event without damage to the protective silicon carbide composite face sheet. Future tests are planned to assess the degradation of the sandwich structure in moist environments. This work was supported by the Next Generation Launch Technology (NGLT) Program. (Point of Contact: 5130/Anthony Calomino, 3-3311; Fran Hurwitz, 3-5503)
On-Orbit Repair of Space Shuttle RCC Leading Edge
Research activities have been initiated in collaboration with MSFC to jointly develop technologies for on-orbit repair of space shuttle RCC leading edge as part of the Return to Flight effort. GRC is developing ceramic patches for the filled wing/inflatable concept proposed by MSFC. The first batch of RCC material with GRC-developed ceramic patch is currently being tested under high heat flux conditions at Air Force Research Laboratory, Dayton, OH. This work is being supported by the Return to Flight Project. (Point of Contact: 5130/Jay Singh, 3- 8883)
Ceramic Matrix Composite Turbine Blades
Ceramic matrix composite (CMC) turbine vanes are being evaluated in pursuit of improving turbine engine performance, such as lower emissions and higher cycle efficiency, relative to today’s engines using superalloy hot section components. Testing and evaluation of this material technology, for airfoil applications, has been completed in the NASA Glenn High Pressure Burner Rig (Level 1 milestone). The geometry was derived from a turbine vane and was fabricated from a silicon carbide fiber-reinforced silicon carbide matrix (SiC/SiC) composite and coated with an environmental barrier coating (EBC). The CMC vanes were exposed to near engine conditions, in terms of velocity and pressure, reaching temperatures above 2400°F with minimal material degradation. During the testing, the rig test section parts, including vanes similar to the CMC vanes, which had been fabricated from superalloys, showed significant damage after more than 55 hours of turbine engine environment testing. This work was funded by the Ultra- Efficient Engine Technology (UEET) program (Point of Contact: 5160/ Michael Verrilli, 3-3337 and 5160/R. Craig Robinson, 3-5547).
Titanium aluminide (TiAl) scramjet inlet flap concept design and fabrication successfully demonstrated
The design and fabrication of a titanium aluminide (TiAl) scramjet inlet flap concept was successfully demonstrated. A conceptual design of the inlet and the design and fabrication of a TiAl sub-element was used to demonstrate considerable weight savings and the design methods required to implement this new material in aerospace applications. The sub-element was designed to demonstrate full-scale manufacturing capability and to validate the design predictions and the properties of this TiAl alloy. Three sub-elements were fabricated by one-pass brazing, one of which will be tested in shear with the applied shear load and location simulated to match anticipated flap shear and moment. This work represents a collaborative effort between GRC, Pratt and Whitney, Engineering Evaluation & Design (EE&D), Plansee AG (Austria), and the Austrian Space Agency. The NASA portion of the work was funded by the NGLT Propulsion Research and Technology Project. (Point of Contact: 5120/ Susan Draper, 3-3257
November 2003
New multi-component rare earth doped coating material developed
A new multi-component rare earth doped hafnia – yttria - gadolinia (or neodymia) – ytterbia coating material has been developed and shown to provide a lower thermal conductivity, improved thermal stability properties and significantly improved radiation resistance as compared to the state-of-the-art yttria-stabilized zirconia thermal barrier coatings. The multi-component HfO2 coating had only a relatively low conductivity increase during the first 20 hours of steady-state laser testing and showed essentially no cracking or delamination during the subsequent 100 cycles, indicating its excellent sintering resistance and cyclic durability. Thermal barrier coatings (TBC) and environmental barrier coatings (EBC) are under study within the Ultra-Efficient Engine Technology (UEET) Project as protection for silicon carbide-reinforced silicon carbide ceramic matrix composite (CMC) materials for combustor and vane applications. The coating, along with the EBC, is essential to extending the CMC liner and vane temperature capability to 1650oC (3000oF) enabling lower emissions and increased operating efficiencies in gas turbine engines. (Points of Contact: 5160/Dr. Robert Miller, 3-3298 and 5160/Dongming Zhu , 3-5422)
Meeting with Battelle Memorial Institute Researchers
The Polymers Branch hosted a meeting with researchers from Battelle Memorial Institute on October 27th to discuss materials related research in Proton Exchange Membrane (PEM) fuel cells and potential areas for collaboration. Follow up discussions are planned to identify collaboration topics and discuss research and funding plans. (Points of Contact: 5150/Dr. James Kinder, 3-3149 and 5160/Dr. Mary Ann Meador, 3-3221)
A new molecular sensor developed
A new molecular sensor has been developed with potential application in the detection of the chemical components of nerve gasses. Exposure of this dye to acids and chemical compounds representative of Sarin and other phosphate ester based nerve gasses causes it to fluoresce a bright blue-green. In the absence of these chemical species, the dye does not fluoresce. There has been considerable interest in the DoD and the Office of Homeland Security in the development of reliable, easy to use methods for the detection of chemical warfare agents. Other potential applications for this dye include cure monitoring for high temperature polyimides. This research has been supported by the Strategic Research Fund. (Points of Contact: 5150/Dr. Michael Meador, 3-9518; OAI/Dr. Faysal Ilhan, 3-6094; and OAI/Dr. Dan Tyson, 3-3188)