Metallurgy Division Publications - NISTIR 7017

Program Overviews

Table of Contents

• Advanced Manufacturing Methods
• Combinatorial Methods
• Data Evaluation and Delivery
• Nanocharacterization
• Interface of Materials with Biology
• Materials for Micro- and Optoelectronics
• Materials Property Measurements
• Materials Structure Characterization

Advanced Manufacturing Methods

Contact Information: Carol A. Handwerker

The industrial competitiveness of U.S. manufacturers depends on their ability to reduce the time from product concept to market while decreasing product cost. This is as true for well-established “commodity” industries, such as automotive and aerospace, as it is for rapidly growing or emerging industries, such as biotechnology and nanotechnology. Manufacturing is a critical step in realizing such reductions in product cycle time: for many industries and products, the rapid, low-cost development of manufacturing processes is needed to create new materials with complex product shapes and higher performance at the same or lower cost as the competing, older materials and methods.

To realize such improvements in manufacturing, MSEL is working to develop robust measurement methods, standards, and materials and process data that will help in the design, monitoring, and control of manufacturing processes. An increasingly important step in manufacturing is process modeling. Development of optimized manufacturing processes, such as stamping of complex auto panels or machining of large aircraft components, is time consuming and labor intensive. In many cases, the resulting processes are far from optimal because materials variability, caused, for example, by residual stresses or strain localization during processing, leads to lower yields. Our approach is to develop and combine higher precision, spatially localized measurement methods with realistic, physics-based modeling of manufacturing processes and materials process data to create more useful process modeling tools.

Depending on the stage of the research, our research is often conducted in close collaboration with industrial consortia and standards organizations. This close working relationship developed through these organizations not only ensures the relevance of our research, but also promotes rapid transfer of our research to industry for implementation.

The performance of metallic components in products is strongly dependent on processing conditions that determine microstructural features, such as grain size and shape, texture, the distribution of crystalline phases, macro- and microsegregation, and defect structure and distribution. NIST expertise is applied from a wide range of disciplines, including thermodynamics, electrochemistry, fluid mechanics, diffusion, x-ray, and thermal analysis, to develop measurement methods and understand the influence of processing steps for industries as diverse as automotive, aerospace, microelectronics, and defense. Two major MSEL efforts in Polymer Processing and Forming of Lightweight Metals are centered on unique measurement facilities. Rapidly growing and emerging industries such as biotechnology and nanotechnology are also dependent upon the development of new advanced manufacturing methods that can produce metallic components with the desired characteristics and performance. Related projects with significant manufacturing processes components can be found in the MSEL Programs on Nanocharacterization, Materials for Micro- and Opto-Electronics, and the Interface of Materials with Biology.

Forming of Lightweight Metals

Automobile manufacturing is a materials intensive industry that involves about 10 % of the U.S. workforce. In spite of the use of the most advanced, cost-effective technologies, this globally competitive industry still has productivity issues related to measurement science and data. Chief among these is the difficulty encountered in die manufacture for sheet metal forming. In the ATP-sponsored workshop (The Road Ahead, June 20–22, 2000), the main obstacle to reducing the time between accepting a new design and actual production of parts was identified as producing working die sets. To benefit from the weight saving of high strength steel and aluminum alloys, a whole new level of formability measurement methods and data is needed, together with a better understanding of the physics behind metal deformation. MSEL is working to fill this need.

Polymers Processing

Polymers have become ubiquitous in the modern economy because of their ease of processing, high functionality, and low cost. However, these materials can exhibit complex and sometimes catastrophic responses to the forces imposed during manufacturing, thereby limiting processing rates and the ability to predict ultimate properties. The focus of our polymer research is on microscale processing, modeling of processing instabilities, and on-line process monitoring of polymers. Our unique extrusion visualization facility combines in-line microscopy and light scattering for the study of polymer blends, extrusion instabilities, and the action of additives. Current applications focus on understanding and controlling the “sharkskin instability” in polymer extrusion and observation of the dielectric properties of polymer nanocomposites. Fluorescence techniques are developed to measure critical process parameters such as polymer temperature and orientation that were hitherto inaccessible. These measurements are carried out in close collaboration with interested industrial partners.

Contact: Carol A. Handwerker

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Combinatorial Methods

Contact Information: Leonid A. Bendersky

The Combinatorial Methods Program develops novel high-throughput measurement techniques and combinatorial experimental strategies specifically geared towards materials research. These tools enable the industrial and research communities to rapidly acquire and analyze physical and chemical data, thereby accelerating the pace of materials discovery and knowledge generation. By providing measurement infrastructure, standards, and protocols, and expanding existing capabilities relevant to combinatorial approaches, the Combinatorial Methods Program lowers barriers to the widespread industrial implementation of this new R&D paradigm.

The Combinatorial Methods Program has adopted a two-pronged strategy for accelerating the development and implementation of combinatorial approaches: an active intramural R&D program and an ambitious outreach activity. The intramural R&D program is designed to better tailor combinatorial methods for the materials sciences and extend the state-of-the-art in combinatorial techniques. Measurement tools and techniques are developed to prepare and characterize combinatorial materials libraries, often by utilizing miniaturization, parallel experimentation, and a high degree of automation. A key concern in this effort is the validation of these new approaches with respect to traditional “one at a time” experimental strategies. Accordingly, demonstrations of the applicability of combinatorial methods to materials research problems provide the scientific credibility needed to engender wider acceptance of these techniques in the industrial and academic sectors. The successful adoption of the combinatorial approach also requires a highly developed “workflow” scheme. All aspects of combinatorial research, from sample “library” design and library preparation to high-throughput assay and analysis, must be integrated through an informatics framework, which enables iterative refinement of measurements and experimental aims. Combinatorial Methods Program research projects give illustrations of how combinatorial methodology is implemented effectively in a research setting.

NIST-wide research collaborations, facilitated by the Combinatorial Methods Program, have produced a wide range of new proficiencies in combinatorial techniques which are detailed in a brochure, “Combinatorial Methods at NIST” (NISTIR 6730), and online at www.nist.gov/combi. Within the Materials Science and Engineering Laboratory (MSEL), novel methods for combinatorial library preparation are designed to encompass variations of diverse physical and chemical properties, such as composition, film thickness, processing temperature, surface energy, chemical functionality, UV-exposure, and topographic patterning of organic and inorganic materials ranging from polymers to nanocomposites to ceramics to metals. New instrumentation and techniques have been developed that enable the high-throughput measurements of adhesion, mechanical properties, and failure mechanisms, film thicknesses, and refractive index, among others. The combinatorial effort extends to multiphase, electronic, optoelectronic, and magnetic materials, including biomaterials assays. On-line data analysis tools, process control methodology, and data archival methods are also being developed as part of the Program’s informatics effort.

The extensive outreach activity in the Combinatorial Methods Program is designed to facilitate technology transfer with institutions interested in acquiring combinatorial capabilities. The centerpiece of this effort is the NIST Combinatorial Methods Center (NCMC), an industry–university– government consortium organized by MSEL that became operational on January 23, 2002 via a kick-off meeting in San Diego. The recognized importance of NCMC activities is readily apparent, as 15 industrial partners, the Air Force Research Lab, and the University of Southern Mississippi are participating in the NCMC membership program. The membership continues to grow and 80% of the members from last fiscal year have already renewed for this fiscal year. The NCMC facilitates direct interaction between NIST staff and these industrial partners, and it provides a conduit by which Combinatorial Methods Program research products, best practices and protocols, instrument schematics and specifications, and other combinatorial-related information can be effectively disseminated. This outreach is mediated in large part by a series of semi-annual workshops for NCMC members. Indeed, since its inception, four NCMC workshops have been held at NIST. Further information on NCMC can be found on the website at www.nist.gov/combi.

Contact: Leonid A. Bendersky

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Data Evaluation and Delivery

Contact Information: Carlos R. Beauchamp

The economic importance of technical data has grown steadily over the past three decades. NBS/NIST took an important lead early in the effort to emphasize the pervasive use and increase the impact of reliable materials property data. As early as 1985, former NBS Director E. Ambler noted that the need for property data had become a “national priority,” while the National Research Council repeatedly observed that there is a persistent “critical national need” for materials property data.

The NIST Materials Science and Engineering Laboratory (MSEL) has been a prominent leader in responding to this national need. By design, the scope of the MSEL effort is evolutionary and responds to the ever-increasing advances in technology. Currently, MSEL has six project areas in the Data and Data Delivery program.

• Crystallographic and Phase Equilibria Databases [Project Leader — V. Karen]: This project encompasses the two most venerable efforts in MSEL, each of which recently has had a major new release. In collaboration with Fachinformationszentrum Karlsruhe (FIZ, Germany), a CDROM version of the FIZ/NIST Inorganic Crystal Structure Database(ICSD) has been released providing the full structural data, i.e., lattice parameters and atomic coordinates, for approximately 60,000 compounds. The long-standing collaboration between NIST and the American Ceramic Society (ACerS) has continued with the completion of a new topical volume in the NIST/ACerS Phase Equilibria Diagrams series, the first of two planned volumes on electronic ceramics.

• Phase Equilibria and Properties of Dielectric Ceramics [Project Leader — T. Vanderah]: An integrated theoretical and experimental effort is underway to predict and measure phase equilibria and electronic behavior in dielectric oxide systems. This work includes relaxor ferroelectrics, dielectrics for cellular infrastructure and hand-held devices, and dielectrics for low temperature co-fired ceramics for applications in multilayer ceramic integrated circuit technology. The impact of this work was evident in Dr. Vanderah’s invited perspective article, “Talking Ceramics,” which appeared in the journal Science. The timeliness of this work was emphasized further by its subsequent feature in the science section of the New York Times.

• Phase Relationships in High Temperature Superconductors [Project Leader — W. Wong-Ng]: MSEL’s meticulous effort to provide phase information critical to the development of practical superconductors is currently directed towards two important systems: Ba₂RCu₃O_7–x, where R is yttrium or a lanthanide, and MgB₂. For Ba₂RCu₃O_7–x, work has focused on the phase relations in BaF₂-BaO-Y₂O₃-CuO_x-H₂O and the interactions of Ba₂RCu₃O_6+x with buffer layers, both of which are important for advances in the “BaF₂ ex situ” process and the “liquid-phase-epitaxy” process. For MgB₂, the enthalpy of formation, vapor pressure, and sources of variability have been determined.

• Reaction Path Analysis in Multicomponent Systems [Project Leader — C. Campbell]: Many industrial processes rely on multicomponent diffusion to control the formation and dissolution of precipitate phases. MSEL is developing a multicomponent diffusion mobility database for Ni-base superalloys that will be used, for example, to predict the formation of the γ′ (ordered FCC) phase during the solidification of superalloys. A workshop, “High Throughput Analysis of Multicomponent Multiphase Diffusion Data,” was held in March 2003 to focus on the development of methods to extract diffusion data from multicomponent diffusion couples.

• Evaluated Materials Property Data [Project Leader — R. Munro]: Engineering designs utilizing advanced materials require reliable data. Elasticity, strength, toughness, hardness, creep, thermal expansion, conductivity, diffusivity, and durability are prominent among the data categories needed and desired for materials applications and development. This project is directed both towards the development of evaluated databases of these properties for structural and superconducting ceramics and towards the establishment of the evaluation methodologies that form the foundation of reliable materials property data systems. A significant achievement in this effort is “Data Evaluation Theory and Practice for Materials Properties,” SP960-11, the eleventh NIST Recommended Practice Guide produced by MSEL.

• Informatics and Visualization in Materials Data Delivery [Project Leader — C. Beauchamp]: The internet, and the World Wide Web in particular, has become a dominant resource medium for technical information. MSEL has undertaken a major commitment to make its extensive data collections available via this medium. New efforts, now underway, will provide web access to the MSEL lead-free solder materials property database and the diffusion data archive that is important for the processing of metal alloys. Additionally, the internet will be used increasingly as a means of disseminating MSEL’s prodigious technical publications in the form of electronic manuscripts.

Contact: Carlos R. Beauchamp

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Nanocharacterization

Contact Information: James A. Warren

The emphasis on nanotechnology around the world and the successful implementation of the National Nanotechnology Initiative in the U.S. are accelerating the development of science and technology at the nanoscale. Nanotechnology is expected to play a key role within the next 10 years in a wide spectrum of industry sectors including manufacturing, information technology, electronics, and healthcare. Novel devices at the micro- and nanoscale will become increasingly important in all of these industries. The ability to measure dimensions, characterize materials, and elucidate structures of new and novel materials at the nanoscale will be critical to the advancement of nanotechnology. In addition, one of the exciting prospects of nanotechnology lies in the ability of molecules or particles, under specific conditions, to self-assemble to form new materials with unusual properties. Successful development of these new materials will require the ability to monitor such processes at the nanoscale in real time. Metrology, the science of measurement, is therefore the foundation of nanotechnology. Standards and reference materials will also provide essential infrastructural support to this emerging technology.

The objective of the program in the NIST Materials Science and Engineering Laboratory (MSEL) is to develop basic measurement metrology at the nanoscale for the determination of bulk and surface material properties and for process monitoring. Measurement methods are being developed for use in conjunction with new instrumentation and calibration artifacts.

The scope of the program encompasses metals, ceramics, and polymers in various forms — particles, thin films, nanotubes, and self-assembled structures — and also includes studies of nanocomposites and liquid-state properties for microfluidics-based fabrication and measurement techniques. Physical properties such as mechanical strength, elastic moduli, friction, stiction, adhesion, and fatigue strength are measured, as well as the size of nanoparticles and the structure and dispersion behavior of nanoparticulate systems. Other properties such as electrical conductivity, thermal conductivity, magnetic properties, electronic properties, and optical properties are also examined. While the program focuses on developing measurement techniques at the nanoscale, proper data interpretation requires fundamental studies in nanomechanics, scaling laws, and imaging techniques.

There are currently ten projects under the program:

• Bridging Length Scales in Theory and Modeling;

• Electrochemical Processing of Nanoscale Materials;

• Metrology for Nanoscale Properties;

• Nanofiller Processing;

• Nanoindentation;

• Nanomechanics and Standards;

• Nanoscale Manufacturing;

• Nanotribology and Surface Properties;

• Particle Metrology and Standards; and

• Physical Properties of Thin Films and Nanostructures.

In many of these individual projects, objectives are directed toward the study of a particular class of materials or material properties, but the underlying theme of the program as a whole is to develop reliable, accurate measurement techniques for a broad range of materials and material properties at the nanoscale. As just one example, four methods for the determination of the elastic properties of thin films — atomic force acoustic microscopy, surface acoustic wave spectroscopy, Brillouin light scattering, and nanoindentation — are being compared using common sets of specimens. This study will lead to a better understanding of the complementary nature of these techniques for measuring nanostructured materials and their combined use to determine supplementary properties such as film thickness or density. Standard reference materials are being developed in collaboration with other National Measurement Institutes around the world for use in the verification of the performance of these instruments.

Contact: James A. Warren

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Interface of Materials with Biology

Contact Information: Frank S. Biancaniello

New materials and devices are radically changing the medical treatment of injury and disease, yet because of the rapid pace of this segment of the materials industry, an adequate measurement infrastructure does not yet exist. The program on the Interface of Materials with Biology develops measurement methods, standards, and fundamental scientific understanding at the interface between materials science and biological science. Within the health care industry, we focus on dental and medical sectors that apply synthetic materials for replacement, restoration, and regeneration of damaged or diseased tissue. Three primary foci exist within this program: biocompatibility, materials properties, and materials science techniques applied to biological systems.

Whether the medical issue involves implanting a hip or knee joint prosthesis, a synthetic bone graft, or a tissue engineering scaffold into the human body, one of the primary issues is biocompatibility. By using our expertise in materials science, we are working to develop suitable Reference Materials (RM) for investigating biocompatibility and implant suitability. Research has focused on measuring the cellular response to powders and bulk materials to identify suitable candidates. We are collaborating with the American Dental Association Foundation (ADAF) to develop metrology methods to characterize the biocompatibility of synthetic bone grafts. Quantitative methods being developed include assays for adhesion, viability, proliferation, and differentiation of bone cells, as well as optical coherence tomography and confocal microscopy for measuring tissue in growth. We are developing biochemical assays to quantify inflammatory responses to synthetic materials. Finally, current research is working to bridge the gap between knowledge generation by cell biologists and product development in industry. In collaboration with the Chemical Science and Technology Laboratory, we are developing measurement methodologies and reference materials to use in assessing interactions in complex systems of living cells with synthetic materials. The expected outcomes of this work are reference substrates that induce specific cellular responses and engineered DNA vectors to act as fluorescent reporters of cellular responses.

In addition to the issue of biocompatibility, it is critical that the materials can withstand the mechanical and environmental stresses placed on them. For metallic implants, one concern is the corrosion pitting resistance of the implant materials and the associated potential for stress corrosion cracking (SCC). To address this issue, metal standards are being subjected to a simulated biological environment which will then be used to develop tests to assess the susceptibility for SCC.

Mechanical properties issues also arise when considering synthetic bone grafts and tissue engineering scaffolds. In addition to traditional bulk mechanical property measurements, combinatorial approaches are used to identify compositions and surface features that affect properties such as biocompatibility and mechanical durability. Finally, because the dental industry is primarily composed of small manufacturers with limited R&D capability, collaborations with the ADAF, located in MSEL, are filling the gap by developing improved materials and techniques, patenting and licensing these inventions, and, most importantly, providing a technical foundation. Research focuses on improved understanding of the synergistic interaction of the phases of polymer-based composites and the mechanisms of adhesion to dentin and enamel. This approach will ultimately lead to materials with improved durability, toughness, and adhesion to contiguous tooth structure.

In this era of interdisciplinary approach to research, we provide an added dimension. By taking a physical/mechanical approach to how cells function, respond, and remodel in interaction with synthetic materials, we can provide skill sets typically absent in the biomedical community. Our concentration on mechanical property metrology extends to biological systems, spanning a considerable size range from individual neurons and muscle cells to complete pulmonary arteries. This necessitates the development of unique mechanical testing platforms and application of a materials science approach to understanding integrated properties.

Fundamental to much of the work in this program is the recognition that surfaces and interfaces play a critical role in biological systems and, in particular, in the interactions of synthetic or designed materials with biological systems and function. By applying the expertise in the NIST Materials Science and Engineering Laboratory to characterization of surfaces and interactions at interfaces in biomaterials, we will accelerate the introduction of improved materials and help provide the means to assure quality control that is critical to this industry.

Contact: Frank S. Biancaniello

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Materials for Micro- and Optoelectronics

Contact Information: Frank W. Gayle

U.S. microelectronics and related industries are in fierce international competition to design and produce smaller, lighter, faster, more functional, and more reliable electronics products more quickly and economically than ever before. At the same time, there has been a revolution in recent years in new materials used in all aspects of microelectronics fabrication.

Since 1994, the NIST Materials Science and Engineering Laboratory (MSEL) has worked closely with the U.S. semiconductor, component, packaging, and assembly industries. These efforts led to the development of an interdivisional MSEL program committed to addressing industry’s most pressing materials measurement and standards issues central to the development and utilization of advanced materials and material processes. The vision that accompanies this program — to be the key resource within the Federal Government for materials metrology development for commercial microelectronics manufacturing — may be realized through the following objectives:

• Develop and deliver standard measurements and data;

• Develop and apply in situ measurements on materials and material assemblies having micrometer- and submicrometer-scale dimensions;

• Quantify and document the divergence of material properties from their bulk values as dimensions are reduced and interfaces contribute strongly to properties;

• Develop models of small, complex structures to substitute for or provide guidance for experimental measurement techniques; and

• Develop fundamental understanding of materials needed in future micro- and opto-electronics.

With these objectives in mind, the program presently consists of projects led by the Metallurgy, Polymers, Materials Reliability, and Ceramics Divisions that examine and inform industry on key materials-related issues. These projects are conducted in concert with partners from industrial consortia, individual companies, academia, and other government agencies. The program is strongly coupled with other microelectronics programs within government and industry, including the National Semiconductor Metrology Program (NSMP) at NIST. Materials metrology needs are also identified through industry groups and roadmaps, including the International Technology Roadmap for Semiconductors (ITRS), the IPC Lead-free Solder Roadmap, the National Electronics Manufacturing Initiative (NEMI) Roadmap, the Optoelectronics Industry Development Association (OIDA) roadmaps, and the National [Magnetic Data] Storage Industry Consortium (NSIC).

Although there is increasing integration within various branches of microelectronics and optoelectronics, the field can be considered in three main areas. The first, microelectronics, includes needs ranging from integrated circuit fabrication to component packaging to final assembly. MSEL programs address materials metrology needs in each of these areas, including lithographic polymers and electrodeposition of interconnects, electrical, mechanical, and physical property measurement of dielectrics (interlevel, packaging, and wireless applications), and packaging and assembly processes (lead-free solders, solder interconnect design, thermal stress analysis, and co-fired ceramics).

The second major area is optoelectronics, which includes work which often crosses over into electronic and wireless applications. Projects currently address residual stress measurement in optoelectronic films, optical and structural characterization of wide bandgap semiconductors, and standards development for III–V compound semiconductors. Cross-laboratory collaborations with EEEL figure prominently in this work.

The third area is magnetic data storage, where the market potential is vast and growing and the technical challenges extreme. NSIC plans to demonstrate a recording density of 1 terabit per square inch — 40 times today’s level — by 2006. To reach these goals, new materials are needed that have smaller grain structures, can be produced as thin films, and can be deposited uniformly and economically. New lubricants are needed to prevent wear as spacing between the disk and head becomes smaller than the mean free path of air molecules. Some measurements require calibration of magnetometers using certified magnetic standards in several different shapes and magnetic strengths, and with a wide range in magnetic character. MSEL is working with the magnetic recording industry to develop measurement tools, modeling software, and standards to help achieve these goals, with MSEL, the Electronics and Electrical Engineering Laboratory, the Physics Laboratory, the Information Technology Laboratory, and the Manufacturing Engineering Laboratory working as partners in this effort.

Contact: Frank W. Gayle

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Materials Property Measurement

Contact Information: Samuel R. Low, III

This program responds both to the Materials Science and Engineering Laboratory (MSEL) customer requests and to the Department of Commerce 2005 Strategic Goal of “providing the information and framework to enable the economy to operate efficiently and equitably.” For example, manufacturers and their suppliers need to agree on how material properties should be measured. Equally important, engineering design depends on accurate property data for the materials that are used.

The MSEL Materials Property Measurement Program works toward solutions to measurement problems on scales ranging from the macro to the nano, in four of the Laboratory’s Divisions (Ceramics, Materials Reliability, Metallurgy, and Polymers). The scope of its activities ranges from the development and innovative use of state-of-the-art measurement systems, to leadership in the development of standardized test procedures and traceability protocols, to the development and certification of Standard Reference Materials (SRMs). A wide range of materials is being studied, including polymers, ceramics, metals, and thin films (whose physical and mechanical properties differ widely from the handbook values for their bulk properties).

Projects are directed toward innovative new measurement techniques. These include:

• Measurement of the elastic, electric, magnetic, and thermal properties of thin films and nanostructures(Materials Reliability Division);

• Alternative strength test methods for ceramics, including cylindrical flexure strength and diametral compression (Ceramics Division); and

The MSEL Materials Property Measurement Program is also contributing to the development of test method standards through committee leadership roles in standards development organizations such as the American Society for Testing of Materials (ASTM) and the International Standards Organization (ISO). In many cases, industry also depends on measurements that can be traced to NIST Standard Reference Materials (SRMs). This program generates the following SRMs for several quite different types of measurements:

• Charpy impact machine verification (Materials Reliability Division);

• Hardness standardization of metallic materials (Metallurgy Division); and

• Hardness standardization and fracture toughness of ceramic materials (Ceramics Division).

Supporting the Materials Property Measurements Program is a modeling and simulation effort to connect microstructure with properties. The Object-Oriented Finite-Element (OOF) software developed at NIST is being used widely in diverse communities for material microstructural design and property analysis at the microstructural level.

In addition to the activities above, all four divisions provide assistance to various government agencies on homeland security and infrastructure issues. Projects include assessing the performance of structural steels as part of the NIST World Trade Center Investigation, advising the Bureau of Reclamation on metallurgical issues involving pipelines and dams, advising the Department of the Interior on the structural integrity of the U.S.S. Arizona Memorial, advising the U.S. Customs Service on materials specifications for ceramics, and advising the Architect of the Capitol on repair procedures for cracks in the outer skin of the Capitol Dome.

Contact: Samuel R. Low

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Materials Structure Characterization

Contact Information: John E. Bonevich

Fundamental to the field of materials science and engineering is the study of the relationships between processing, structure, properties, and performance of materials. Therefore, tools and techniques for the characterization of materials structure is a cornerstone of the field. The NIST Materials Science and Engineering Laboratory (MSEL) has a long tradition of supporting and developing measurement methods and facilities for materials structure characterization. Facilities within MSEL include optical and electron microscopy, optical and electron scattering and diffraction, a state-of-the-art x-ray diffractometer, the NIST Center for Neutron Research, and experimental stations at the National Synchrotron Light Source (NSLS) at Brookhaven Laboratory and at the Advanced Photon Source (APS) at Argonne National Laboratory. At the NSLS, NIST operates a soft x-ray station in partnership with Dow and Brookhaven National Laboratory. At the APS, NIST is a partner with the University of Illinois at Urbana/Champaign, Oak Ridge National Laboratory, and UOP in a collaboration called UNICAT. At both facilities, NIST scientists and researchers from industry, universities, and government laboratories perform state-of-the-art measurements on a wide range of advanced materials. NIST scientists have consistently advanced the limits of these facilities in order to improve spatial resolution and sensitivity needed, for example, to interrogate the microstructure of both highly anisotropic and/or gradient materials such as advanced thermal coatings and fuel cell systems. Studies currently underway at these facilities include: in-situ measurements of nanoparticle production; structure and dispersion of carbon nanotubes; three-dimensional imaging of natural and artificial tissues; surface and subsurface damage in UV lithography optics; strain-induced ferroelectric transitions in thin films; and determination of molecular orientation and bond concentration on chemically heterogeneous surfaces.

The materials characterization program has a strong emphasis on electron microscopy. The MSEL Electron Microscopy Facility provides structure and compositional characterization of a wide range of materials. The facility consists of two transmission electron microscopes (TEMs), three scanning electron microscopes (SEMs), a specimen preparation laboratory, and an image analysis/computational laboratory. The JEM3010 TEM resolves the atomic structure and employs an energy selecting imaging filter and x-ray detector (EDS) for analytical characterization of thin foil specimens. The JSM6400 SEM employs electron backscattered diffraction /phase identification and EDS systems to characterize the texture and composition of materials. Highlights from the facility for FY2003 include: the computer domain is now active, providing streamlined user access and network file storage; a research collaboration with the NIST Semiconductor Electronics Division is underway to characterize quantum effects in confined Si devices; the size and shape of III–V quantum dots are characterized with the NIST Optoelectronics Division; and composition maps of electrodeposited nanowires with tunable magnetic properties are generated in collaboration with Johns Hopkins University.

This MSEL program also incorporates standards activities. A state-of-the-art x-ray diffractometer has been developed to study the metrology of powder diffraction in order to develop the next generation of diffraction standard reference materials. A variety of standard reference materials (SRMs) needed by the U.S. polymers industry, research laboratories, and other federal agencies have recently been developed: polyethylene of narrow mass distribution; nonlinear fluids for rheological measurements; melt flow standards; and the first reference biomaterial, an orthopedic grade ultra-high molecular weight polyethylene.

Recent program activities utilize matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MS) to address the need for improved characterization of the molecular structure of polyolefins, a dominant commercial polymer. This work has extended the upper mass limit detectable by MS to 15,000 g/mol and, by observing individual oligomeric species by mass, has revealed details of the molecular structure.

A major cross-cutting activity within this program is the multi-scale, multi-modal imaging and visualization project. The goal of this project is to combine disparate sets of 3-D imaging data that contain complementary information on overlapping length scales to produce an interactive visualization scheme for multivariate data sets. This year focused on further improvements and additions to the suite of imaging tools for tissue engineering metrology. Osteoblasts cultured in a poly (ε-caprolactone) scaffold have been imaged, demonstrating the advantages of optical coherence and confocal fluorescence microscopies over conventional laser scanning confocal microscopy. This instrument was upgraded by completely rebuilding the image acquisition software, hardware, and optical train. These improvements enabled an increase in image acquisition speed (2X) and accuracy (from 5 µm to 360 nm).

Contact: John E. Bonevich

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