NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.
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This study by the National Materials Advisory Board was conducted under Contract No. MDA972-92-C-0028 with the Defense Advanced Research Projects Agency. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors(s) and do not necessarily reflect the views of the organizations or agencies that provided support for the project.
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COMMITTEE ON ADVANCED FIBERS FOR HIGH-TEMPERATURE CERAMIC COMPOSITES
DAVID W. JOHNSON (chair),
Lucent Technologies, Murray Hill, New Jersey
ANTHONY G. EVANS,
Harvard University, Cambridge, Massachusetts
RICHARD W. GOETTLER,
McDermott Technology-Lynchburg Research Center, Lynchburg, Virginia
MARTIN P. HARMER,
Lehigh University, Bethlehem, Pennsylvania
JONATHAN LIPOWITZ,
Dow Corning Corporation, Midland, Michigan
KRISHAN L. LUTHRA,
General Electric Corporate Research and Development, Schenectady, New York
PAUL D. PALMER,
Thermo Fibergen, Bedford, Massachusetts
KARL M. PREWO,
United Technologies Research Center, East Hartford, Connecticut
RICHARD E. TRESSLER,
Pennsylvania State University, University Park
DAVID WILSON,
3M Corporation, St. Paul, Minnesota
National Materials Advisory Board Staff
SANDRA HYLAND, senior program manager
CHARLES T. HACH, research associate
JANICE M. PRISCO, project assistant
ROBERT E. SCHAFRIK, director (until November 1997)
RICHARD CHAIT, director (after February 1998)
Government Liaison Representatives
ERNEST CHIN,
Army Research Laboratory, Aberdeen Proving Ground, Maryland
JAMES A. DICARLO,
NASA Lewis Research Center, Cleveland, Ohio
STEVEN FISHMAN,
Office of Naval Research, Arlington, Virginia
RONALD KERANS,
Wright-Patterson Air Force Base, Ohio
S. CARLOS SANDAY,
Naval Research Laboratory, Washington, D.C.
MERRILL SMITH,
U.S. Department of Energy, Washington, D.C.
NATIONAL MATERIALS ADVISORY BOARD
ROBERT A. LAUDISE (chair),
Lucent Technologies, Murray Hill, New Jersey
G.J. ABBASCHIAN,
University of Florida, Gainesville
MICHAEL I. BASKES,
Sandia/Livermore National Laboratory, Livermore, California
JESSE (JACK) BEAUCHAMP,
California Institute of Technology, Pasadena
FRANCIS DiSALVO,
Cornell University, Ithaca, New York
EARL DOWELL,
Duke University, Durham, North Carolina
EDWARD C. DOWLING,
Cyprus Amax Minerals Company, Englewood, Colorado
THOMAS EAGAR,
Massachusetts Institute of Technology, Cambridge
ANTHONY G. EVANS,
Harvard University, Cambridge, Massachusetts
JOHN A. GREEN,
The Aluminum Association, Washington, D.C.
SIEGFRIED S. HECKER,
Los Alamos National Laboratory, Los Alamos, New Mexico
JOHN H. HOPPS, JR.,
Morehouse College, Atlanta, Georgia
LISA KLEIN,
Rutgers, The State University of New Jersey, Piscataway, New Jersey
MICHAEL JAFFE,
Hoechst Celanese Corporation, Summit, New Jersey
SYLVIA M. JOHNSON,
SRI International, Menlo Park, California
HARRY LIPSITT,
Wright State University, Yellow Springs, Ohio
ALAN G. MILLER,
Boeing Commercial Airplane Group. Seattle, Washington
RICHARD S. MULLER,
University of California, Berkeley
ROBERT C. PFAHL,
Motorola, Schaumburg, Illinois
ELSA REICHMANIS,
Lucent Technologies, Murray Hill, New Jersey
KENNETH L. REIFSNIDER,
Virginia Polytechnic Institute and State University, Blacksburg
JAMES WAGNER,
Case Western Reserve University, Cleveland, Ohio
BILL G.W. YEE,
Pratt and Whitney, West Palm Beach, Florida
Preface
The U.S. Department of Defense and the National Aeronautics and Space Administration requested that the National Research Council (NRC) conduct a study to recommend future research and development for advanced ceramic fibers and fiber coatings for high-temperature ceramic matrix composites (CMCs). The scope of this study was limited to fibers and their coatings or interfaces, independent of CMC processing and matrix materials, to bring to the forefront the current limitations on the strength and toughness of CMCs, particularly at high temperatures. This report represents the work of the Committee on Advanced Fibers for High-Temperature Ceramic Composites, under the auspices of the National Materials Advisory Board, which was established by the NRC for this purpose.
The properties of the principal classes of high-performance synthetic fibers, as well as several methods of synthesizing and processing them, were discussed in a 1992 NRC report entitled High-Performance Synthetic Fibers for Composites. This report included an excellent assessment of fibers for polymer matrix and metal matrix composites and CMCs, carbon-carbon composites, as well as fibers for nonstructural applications. The 1992 report, however, did not address microstructure/property relationships in ceramic fibers or the relationship between processing and property retention at elevated temperatures. Since the publication of the 1992 report, the need for improved fiber coatings has been more widely identified as critical. In light of the continuing demand for higher temperature performance, this report is focused on the capabilities and requirements of ceramic fibers and ceramic fiber coatings.
The need for improved high-temperature materials is evident in the continuing drive by industry, government, and academia to improve the performance, efficiency, and durability of components used in high-temperature applications. For example, a recent NRC report, Intermetallic Alloy Development: A Program Evaluation, describes the objective of the Oak Ridge National Laboratories intermetallics program as the development of intermetallic alloys for high-temperature structural applications. A 1996 NRC report, Coatings for High-Temperature Structural Materials: Trends and Opportunities, discusses ways to protect the metallic components of turbine engines from their operating environments so they can be used at higher temperatures. Because of the inherent stability of CMCs at high temperatures, they continue to hold great promise for use at high temperatures. Successful implementation of CMCs, however, will require assessing the performance and cost of the constituent fibers and fiber coatings. Therefore, the committee was asked to fulfill the following objectives in this study:
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Characterize the current state of the art in high-temperature fibers and interface materials and identify current domestic and foreign research and development capabilities and production capabilities.
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Assess the capability of current fibers to meet future performance needs.
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Recommend promising directions for research on fibers and coatings to improve performance at high temperatures.
-
Identify materials processing technologies that have the potential to produce high-temperature ceramic fibers and coatings cost effectively.
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Identify incentives for and barriers to the development of commercial-scale high-temperature fibers for low volume applications.
Initially, the committee had intended to address Japanese fiber and coating efforts in a separate section. Given the advances that have been made in the United States and Europe, however, the committee determined that a section dedicated solely to Japanese efforts was not warranted. The state of the art in ceramic fiber and coating technology—in the United States, Europe, and Japan—is discussed in Chapter 3.
To address the study objectives, the committee met four times over a period of 15 months interspersed with several teleconferences. Two of the face-to-face meetings were focused on gathering information, and two were devoted to analyzing information and producing the report. Representatives of the National Aeronautics and Space Administration, the U. S. Department of Defense, and the U.S. Department of Energy materials programs, as well as representatives of nongovernmental entities, were invited to discuss the longterm material performance requirements of high-temperature components and the capability of current materials to fulfill them. Current producers of CMCs were requested to define fiber requirements for composite fabrication, as well as composite performance and supply capabilities.
One of the information gathering meetings was held in parallel with the American Ceramic Society's 21st Annual Conference on Composites, Advanced Ceramics, Materials, and Structures, in Cocoa Beach, Florida. At this meeting, the committee attended 15 presentations given by representatives of industry, government, and academe from the United States, Japan, and Germany. Presentations were, for the most part, focused on the current status and future directions of fiber and coatings technologies. In addition, two of the major manufacturers of jet engines presented the general requirements for CMCs to be used in gas turbine engines. The information collected by the committee was used to assess the current state of the art in ceramic fiber and coating technology and to determine the direction researchers and manufacturers should take to further these technologies. At a second information gathering meeting, held at the National Academy of Sciences in Washington, D.C., several representatives of CMC manufacturers discussed their requirements for ceramic fibers and ceramic fiber coating capabilities.
After reviewing these briefings, the committee considered the following questions:
-
What requirements for fibers and interfaces are created by CMC processing?
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What are the major CMC markets/applications?
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What are the requirements for fibers and fiber coatings for these markets?
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Do available fibers meet or come close to meeting CMC requirements now?
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How sensitive are current and potential CMC applications to the costs of fibers?
The committee then considered future needs and opportunities for improving the performance and lowering the cost of ceramic fibers and coatings. The discussion included processing improvements that have the potential for improving fibers and coatings, as well as mechanisms for reducing (to some extent) the cost of developing and manufacturing these materials. Finally, the committee developed the conclusions and recommendations presented in this report.
David W. Johnson, chair
Committee on Advanced Fibers for High-Temperature Ceramic Composites
Acknowledgments
The Committee on Advanced Fibers for High-Temperature Ceramic Composites gratefully acknowledges the information provided by the following individuals: Hans-Peter Baldus, Bayer AG; Ted Besmann, Oak Ridge National Laboratory; John Brennan, United Technologies Research Center; Mike Burke, Westinghouse; Phillip Craig, DuPont Lanxide, Inc.; Said El-Rahaiby, Department of Defense-Ceramics Information Analysis Center; Dick Enghalt, Synterials; Doug Freitag, Dupont Lanxide; Hans Friedericy, AlliedSignal; Randy Hay, Wright Patterson Laboratory; Bill Hong, Institute for Defense Analysis; K. William Householder, Dow Corning; Hiroshi Ichikowa, Nippon Carbon Company; Kioyshi Kumagawa, UBE Industries; Withold Kowbel, Materials and Electrochemical Research Group; Gary Linsey, Pratt and Whitney; Richard Lowden, Oak Ridge National Laboratory; Michael Millard, General Electric; Peter Morgan, Rockwell International; Koichi Niihara, Osaka University; Paul Nordine, Containerless Research Corporation; John Porter, Rockwell International; Michael Sacks, University of Florida; Andrew Szweda, Dow Corning; Michio Takeda, Nippon Carbon Company; Tom Tompkins, 3M Company; Richard Wagner, McDermott Technologies, Inc.; and Richard Weber, Containerless Research Corporation.
The committee would like to thank the American Ceramic Society for granting the National Research Council permission to use the following figures in this report: Figures 3-1, 3-2, 3-6, 3-8, 3-12, 3-13, 3-15, 3-16, 3-17, 3-21, 3-23, 3-24, 4-2, 5-2, 5-3, 6-6, 6-8, 6-9, 6-10, 6-12, 6-14, 6-15, 6-16, 6-17 and 6-18. These figures were reprinted with permission of The American Ceramic Society, Post Office Box 6136, Westerville, Ohio 43086-6136. The American Ceramic Society maintains copyright to all of the aforementioned figures. All rights reserved.
This report has been reviewed by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the NRC's Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the authors and the NRC in making the published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The content of the review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their participation in the review of this report: Norbert S. Baer, New York University; John J. Brennan, United Technologies Research Center; I. Wei Chen, University of Pennsylvania; Barry S. Draskovich, Allied Signal; Sylvia M. Johnson, SRI International; Harry A. Lipsitt, Wright State University; David B. Marshall, Rockwell International Science Center; and Dennis C. Nagle, Johns Hopkins University.
While the individuals listed above have provided many constructive comments and suggestions, responsibility for the final content of this report rests solely with the authoring committee and the NRC.
The committee wishes to express its sincere appreciation to the staff of the National Materials Advisory Board for its unswerving support. Sandra Hyland, senior program officer, and Charles Hach, research associate, dedicated much time and energy to bringing the report into being. Janice Prisco very effectively handled many issues as the senior project assistant.
The committee chair especially thanks the committee members for their dedication to producing a high-quality report on a tight schedule. Without their freely given time and efforts, this report would not have been possible.
Tables, Figures, and Boxes
TABLES
|
ES-1 |
Typical Property Ranges for Ceramic Fibers, |
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2-1 |
CMC Performance Attributes and Weaknesses, |
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2-2 |
Industrial Power Generation Applications, |
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2-3 |
Aircraft Applications, |
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2-4 |
Space Applications (United States), |
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2-5 |
CMC Processing Environments, |
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3-1 |
Commercially Available and Developmental Ceramic Fiber for CMCs, |
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3-2 |
Selected Commercially Available Ceramic Fibers, |
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4-1 |
Processes for Commercial and Developmental Polymer-Derived Ceramic Fibers, |
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4-2 |
Composition and Precursors of Commercially Available Oxide Fibers, |
FIGURES
|
1-1 |
Ideal stress-strain behavior of continuous fiber-reinforced CMC compared to the stress-behavior of an unreinforced matrix, |
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1-2 |
A schematic representation of the constituents of a CMC, |
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1-3 |
A scanning electron micrograph of the fracture surface of a Hi-Nicalon fiber-reinforced SiC matrix composite made by chemical vapor infiltration (CVI) showing fiber pullout, |
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1-4 |
A set of “Saturn” turbine engine combustor liners (inner and outer) fabricated by DuPont Lanxide Composites, Inc., |
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1-5 |
Eight-harness woven cloth, |
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1-6 |
Single filament of boron nitride-coated Nippon Carbon Nicalon™ non-oxide ceramic fiber, |
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1-7 |
Tow of 3M Nextel 610 polycrystalline ceramic oxide fibers, |
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2-1 |
Cross section of the hot stage components of a General Electric large utility gas turbine, |
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2-2 |
Thermal performance requirements for various high-temperature applications, |
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2-3 |
3M Type 203 Nextel fiber-reinforced SiC matrix ceramic composite candle filter, |
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3-1 |
Strength vs. temperature of SiC-based fibers and oxide fibers, |
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3-2 |
(a)Young's moduli vs. temperature for SiC-based fibers. (b) Young's moduli vs. temperature for oxide fibers, |
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3-3 |
Tensile strength vs. temperature of various SiC fibers, |
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3-4 |
Fast fracture strength at temperature for commercial fibers based on silicon compounds and alumina, |
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3-5 |
Room-temperature strength retention after short thermal exposure (one to ten hrs) of commercial silicon-based and alumina-based fibers, |
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3-6 |
Tensile strength of SiC fibers after heat treatment in argon for one hour, |
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3-7 |
Room-temperature tensile strength of SiC fibers after 10-hour thermal exposure in argon, |
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3-8 |
Tensile strength of silicon carbide fibers after aging for 10 hours at 1,550°C (2,822°F) in argon, |
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3-9 |
Tensile strength of SiC fibers after exposure for 10 hours in dry air at 1,400°C (2,552°F), |
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3-10 |
Tensile strength of SiC fibers after heat treatment at 1,000°C (1,832°F) in air, |
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3-11 |
Structure of the diffusion barrier coating forming on oxidation at the surface of SiBN3C, |
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3-12 |
Temperature dependence of electrical conductivity in heat-treated Si-C-O fibers, |
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3-13 |
Relationship between electrical resistivity and C/Si molar ratio in Si-C fiber, |
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3-14 |
One-hour stress relaxation ratio of polymer-derived SiC fibers and other polycrystalline SiC and Al2O3 fibers, |
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3-15 |
Rupture strength of SiC fibers in air (open symbols) and argon (closed symbols) at 1,200°C (2,192°F) (?) and 1,400°C (2,552°F) (?), |
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3-16 |
Thermal activation plot for Hi-Nicalon fast fracture and rupture strength in air, |
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3-17 |
Thermal activation plots for average strength of as-produced SiC fibers, |
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3-18 |
Tensile strength as a function of test temperature for Nextel 610 and Nextel 720 single fibers, |
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3-19 |
Typical creep curves for polycrystalline alumina-based oxide fibers at 1,090°C (1,994°F) in air, |
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3-20 |
Creep rate of Nextel 720 compared to other commercial oxide fibers, |
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3-21 |
One-hour bend stress relaxation ratio for directionally solidified eutectic YAG/alumina fibers grown by edge-defined film growth (EFG), for polycrystalline alumina-based fibers, and for c-axis sapphire fibers, |
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3-22 |
Stress rupture plot for Nextel 610 fibers, |
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3-23 |
The 100-hour rupture strength of polycrystalline and monofilament alumina-based fibers, |
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3-24 |
Thermal activation plots for average strength of as-produced Al2O3-based fibers at a gauge length of ~25 mm (1 in), |
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3-25 |
Comparison of optimum strength map of Al2O3 fiber-reinforced CMC with strength behavior of an advanced superalloy, |
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4-1 |
Typical processing scheme for producing ceramic fibers from organometallic polymer precursors, |
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4-2 |
Schematic illustration of the pyrolysis process, |
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4-3 |
Flow chart of chemical processing of ceramic oxide fibers, |
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4-4 |
Schematic illustration of the dry-spinning process, |
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4-5 |
Differential thermal analysis (DTA), differential thermogravimetric analysis (DTGA), and thermogravimetric analysis (TGA) of chemically-derived alumina fiber, |
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4-6 |
a-Al2O3 fiber with large grain size resulting from low nucleation density, |
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4-7 |
Nextel 610 fiber showing small grain size resulting from the addition of nucleation agents, |
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5-1 |
Predicted creep rates for alumina fibers as a function of aspect ratio using a two-dimensional model, |
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5-2 |
Tensile creep rate of Al2O3-SiC nanocomposite containing 5 volume percent of 0.15 µm (0.006 mils) SiC particles and undoped Al2O3 of the same grain size, |
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5-3 |
The steady-state tensile creep rate for undoped alumina and alumina doped with 1,000 ppm Y2O3, |
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5-4 |
High resolution secondary ion mass spectroscopy compositional maps showing dopant segregation in yttrium and lanthanum doped alumina, |
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6-1 |
Tensile test results of Nicalon fiber-reinforced SiC matrix composites prepared by CVI, |
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6-2 |
Schematic representations of the progression of oxidation along the fiber/coating/matrix interface of uniaxial SiC/C/SiC composites with fiber ends exposed, |
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6-3 |
Depth of oxidation of fiber coatings for uniaxial SiC/C/SiC composites with fiber ends exposed, |
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6-4 |
Tensile test results of Hi-Nicalon fiber-reinforced SiC-Si matrix composites prepared by melt infiltration, |
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6-5 |
Tensile test results for hot pressed Nicalon SiC fiber-reinforced glass-ceramic matrix composites with a BN fiber coating, |
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6-6 |
Depth of coating oxidation in Hi-Nicalon fiber-reinforced SiC-Si matrix composites prepared by melt infiltration, |
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6-7 |
Polished section of a hot pressed SiC fiber-reinforced glass-ceramic matrix composite with a BN fiber coating exposed to a tensile stress rupture experiment at 1,200°C (2,192°F), 69 MPa (10 ksi), 11,725 hours in air, |
|
6-8 |
A schematic representation of the matrix cracking on exposure to stresses above the matrix cracking strength in continuous fiber-reinforced ceramic composites, |
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6-9 |
Schematic representations of the progression of oxidation in a crack/matrix/fiber coating region shown in the elliptical region in Figure 6-8, |
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6-10 |
Porous alumina fiber coating deposited from a mixture of boehmite and Darvan C, |
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6-11 |
Effect of thermal exposure on the ambient stress-strain behavior for all-oxide composites in the 0°/90° orientation, |
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6-12 |
Nextel 720 fiber-reinforced calcium aluminosilicate glass-ceramic matrix composites show significant modulus retention following carbon interface burnout indicating matrix-to-fiber load transfer, |
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6-13 |
Hexagonal ß-alumina (NaAl11O17) and magnetoplumbite (hibonite [CaAl12O19]) structures, |
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|
6-14 |
Transmission electron micrographs of cracks propagating transgranularly along the basal planes of the textured hibonite interphase, |
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6-15 |
Scanning electron micrograph showing crack deflection at alumina-monazite interfaces, |
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6-16 |
Scanning electron micrograph and transmission electron micrograph showing debonding along scheelite-Nextel 610 interfaces, |
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|
6-17 |
Schematic illustration of immiscible liquid coating technique, |
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6-18 |
Example of oxide fiber coatings deposited via the immiscible liquid coating technique (ErTaO4-coated Nextel 610 fibers in an alumina-ErTaO4 matrix), |
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|
6-19 |
LaPO4 coatings on Nextel 720 fibers deposited by heterocoagulation techniques, |
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|
7-1 |
Elements in manufacturing costs, |
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|
7-2 |
Fiber price premiums, |
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|
7-3 |
Projected costs of fibers as a function of annual production, |
BOXES
Acronyms
ACF
activated carbon fiber
BSR
bend stress relaxation
CFCC
continuous fiber-reinforced ceramic composite
CMC
ceramic matrix composite
CTE
coefficient of thermal expansion
CVD
chemical vapor deposition
CVI
chemical vapor infiltration
DTA
differential thermal analysis
DTGA
differential thermal gravimetric analysis
EFCC
externally fired combined cycle
IGCC
integrated gasification combined cycle
IMC
intermetallic matrix composite
MMC
metal matrix composite
NMR
nuclear magnetic resonance
NRC
National Research Council
PAN
polyacrylonitrile
PFBC
pressurized fluid bed combustion
PMC
polymer matrix composite
R&D
research and development
TEM
transmission electron microscopy
TGA
thermal gravimetric analysis
TPV
thermophotovoltaic
UCSB
University of California-Santa Barbara
UF
University of Florida
UHC
unburned hydrocarbons
UTS
ultimate tensile strength
