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in creator/contributor: "Headley, T"

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Microstructural characterization of glass and ceramic simulated waste forms

The microstructures of three nonradioactive glass samples simulating three Hanford process waste forms were characterized. Two samples of iodine sodalite which simulate the fixation of radioactive iodine were also characterized. X-ray diffraction, electron microscopy + x-ray energy dispersive spectrometry, and electron microprobe analysis were used in the characterization. (DLC)

Date: 1979~

Creator: Headley, T. J.; Healey, J. T.; Hlava, P. F.; Kupfer, M. J. & Strachan, D. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Characterization of polysilicon films by Raman spectroscopy and transmission electron microscopy: A comparative study

Samples of chemically-vapor-deposited micrometer and sub-micrometer-thick films of polysilicon were analyzed by transmission electron microscopy (TEM) in cross-section and by Raman spectroscopy with illumination at their surface. TEM and Raman spectroscopy both find varying amounts of polycrystalline and amorphous silicon in the wafers. Raman spectra obtained using blue, green and red excitation wavelengths to vary the Raman sampling depth are compared with TEM cross-sections of these films. Fi… more

Date: November 12, 1993

Creator: Tallant, D. R.; Headley, T. J.; Medernach, J. W. & Geyling, F.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Continuum fluorescence of Cu in NbTi/Cu composite wires

Continuum fluorescence across interfaces separating regions of differing composition is difficult to calculate. This paper illustrates a case of continuum fluorescence in analysis of superconducting NbTi/Cu composite wire which could lead to erroneous compositions due to Cu fluorescence by continuum x rays generated in an NbTi alloy. An approximate treatment of the continuum fluorescence is presented. 3 figs, 4 refs.

Date: April 1, 1994

Creator: Hlava, P. F.; Michael, J. R.; Nelson, G. C. & Headley, T. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Strong segregation gettering of transition metals by implantation-formed cavities and boron-silicide precipitates in silicon

We have mechanistically and quantitatively characterized the binding of transition-metal impurities in Si to cavities formed by He implantation and to B-Si precipitates resulting from B implantation. Both sinks are inferred to act by the segregation of metal atoms to pre-existing low-energy sites, namely surface chemisorption sites in the case of cavities and bulk solution sites in the case of the B-Si phase. These gettering processes exhibit large binding energies, and they are predicted to re… more

Date: June 1, 1996

Creator: Myers, S. M.; Petersen, G. A.; Follstaedt, D. M. & Headley, T. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Structural and compositional transformations of biomass chars during combustion

In an investigation of the physical and chemical transformations of biomass chars during combustion, we have subjected two chars, produced from the pyrolysis of pine and switchgrass, to combustion at 1600 K in a laminar flow reactor. In order to obtain time-resolved data on the structural and compositional transformations of the biomass chars, samples are extracted from the reactor at different residence times and subjected to a variety of analytical techniques: elemental analysis, scanning ele… more

Date: February 1, 1994

Creator: Wornat, M. J.; Hurt, R. H.; Yang, N. Y. C. & Headley, T. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Non-destructive characterization of porous silicon using X-ray reflectivity

Understanding the evolution of porous silicon (PS) layers at the early stages of growth is important for determining the mechanism of PS film growth and controlling the film properties. We have used X-ray reflectivity (XRR) to determine the evolution of layer thickness and interfacial roughness during the growth of thin PS layers (< 200 mn) prepared by electrochemical anodization. The porous layer grows at a constant rate for films as thin as 15 mn indicating a very short incubation period duri… more

Date: January 1, 1995

Creator: Chason, E.; Guilinger, T. R.; Kelly, M. J.; Headley, T. J. & Howard, A. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Mineral matter effects on char structural evolution and oxidation kinetics during coal char combustion

The authors report on recent investigations of the evolution of char structure during carbon burnout and the role of mineral matter in determining this structure. Char samples collected in a carefully controlled laminar, flame-supported entrained flow reactor have been characterized using a number of microscopy tools. Observations of the inorganic structure of chars produced at a variety of combustion conditions are coupled with in-situ optical measurements of the char particle population with … more

Date: October 1, 1997

Creator: Lunden, M.; Yang, N.; Headley, T.; Shaddix, C. & Hardesty, D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Relationships between ferroelectric 90{degree} domain formation and electrical properties of chemically prepared Pb(Zr,Ti)O{sub 3} thin films

For PZT films deposited on Pt coated substrates, remanent polarization is a monotonic function of thermal expansion of the substrate, a result of 90{degree} domain formation occurring as the film is cooled through the transformation temperature. PZT film stress in the vicinity of the Curie point controls 90{degree} domain assemblages within the film. PZT films under tension at the transformation temperature area-domain oriented; whereas, films under compression at the transformation temperature… more

Date: July 1, 1994

Creator: Tuttle, B. A.; Garino, T. J. Voigt, J. A.; Headley, T. J.; Dimos, D. & Eatough, M. O.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Oriented lead zirconate titanate thin films: Characterization of film crystallization

Film processing temperature and time was varied to characterize the pyrochlore-to-perovskite crystallization of solution-derived PZT 20/80 thin films. 3000 {Angstrom} thick films were prepared by spin deposition using <100> single crystal MgO as substrate. By controlled rapid thermal processing, films at different stages in the perovskite crystallization process were prepared with the tetragonal PZT 20/80 phase being <100>/<001> oriented relative to the MgO surface. An activation energy for the… more

Date: November 1, 1993

Creator: Voigt, J. A.; Tuttle, B. A.; Headley, T. J.; Eatough, M. O.; Lamppa, D. L. & Goodnow, D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Metal gettering by boron-silicide precipitates in boron-implanted silicon

We show that Fe, Co, Cu, and Au impurities in Si are strongly gettered to boron-silicide precipitates formed by supersaturation B implantation and annealing. Effective binding free energies relative to interstitial solution range form somewhat above 1 to more than 2 eV. The B-Si precipitates formed at temperatures {le}1100{degrees}C lack long range structural order but closely resemble and icosahedral B{sub 3}Si phase in composition, local bonding, and chemical potential. Evidence indicates tha… more

Date: September 1, 1996

Creator: Myers, S. M.; Petersen, G. A.; Headley, T. J.; Michael, J. R.; Aselage, T. A. & Seager, C. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Aging and Phase Stability of Alloy 22 Welds FY04 SUMMARY REPORT

The work presented in this report consists of a compilation of individual activity reports sent to BSC at the conclusion of the FY04 fiscal year. A chapter is dedicated for each individual activity, and describes the accomplishments at the time of writing the original reports, and includes experimental data when appropriate. It is important to note that since work for most of the activities was intended for completion in FY05, no DTN numbers are given in the present report and the results prese… more

Date: January 3, 2006

Creator: El-Dasher, B S; Torres, S G; McGregor, M M; Edgecumbe, T S; Yang, N; Headley, T et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

La{sub 0.5}Sr{sub 0.5}CoO{sub 3} electrode technology for Pb(Zr, Ti)O{sub 3} thin film nonvolatile memories

Oxide electrode technology is investigated for optimization of Pb(Zr,Ti)O{sub 3} (PZT) thin film capacitor properties for high density nonvolatile memory applications. PZT thin film capacitors with RF sputter deposited La{sub 0.5}Sr{sub 0.5}CoO{sub 3} (LSCO) electrodes have been characterized with respect to the following parameters: initial dielectric hysteresis loop characteristics, fatigue performance, microstructure and imprint behavior. Our studies have determined that the fatigue of PZT c… more

Date: July 1, 1995

Creator: Tuttle, B. A.; Al-Shareef, H. N.; Warren, W. L.; Raymond, M. V.; Headley, T. J. & Voigt, J. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Ion-implanted hydrogen in gallium nitride

Hydrogen was ion-implanted into GaN at concentrations ranging over two orders of magnitude, and its states and microstructural effects during annealing up to 1000 C were characterized by nuclear-reaction profiling, ion-channeling analysis, transmission electron microscopy, and infrared spectroscopy of H vibrational modes.

Date: August 1, 1998

Creator: Myers, S. M.; Han, J.; Headley, T. J.; Hills, C. R.; Petersen, G. A.; Seager, C. H. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Compilation of diamond-like carbon properties for barriers and hard coatings

Diamond-like carbon (DLC) is an amorphous form of carbon which resembles diamond in its hardness, lubricity, and interest for hardness, lubricity, and resistance to chemical attack. Such properties make DLC of use in barrier and hard coating technology. This report examines a variety of properties of DLC coatings which are relevant to its use as a protective coating. This includes examining substrates on which DLC coatings can be deposited; the resistance of DLC coatings to various chemical age… more

Date: February 1, 1994

Creator: Outka, D. A.; Hsu, Wen L.; Boehme, D. R.; Yang, N. Y. C.; Ottesen, D. K.; Johnsen, H. A. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Aging and Phase Stability of Alloy 22 Welds FY05 SUMMARY REPORT

Evaluation of the fabrication processes involved in the manufacture of waste containers is important as these processes can have an effect on the metallurgical structure of an alloy. Since material properties such as strength, toughness, aging kinetics and corrosion resistance are all dependent on the microstructure, it is important that prototypes be built and evaluated for processing effects on the performance of the material. Of particular importance are welds, which have an as-cast microstr… more

Date: November 23, 2005

Creator: Torres, S G; El-Dasher, B; McGregor, M; Etien, R; Edgecumbe, T S; Gdowski, G et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

LDRD Final Report: Exploiting LENS Technology Through Novel Materials

No Description Available.

Date: April 1, 2001

Creator: Brooks, J. A.; Robino, C. V.; Griffith, M. L.; Headley, T. J.; Yang, N. C. Y.; Goods, S. H. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Compilation of diamond-like carbon properties for barriers and hard coatings

Diamond-like carbon (DLC) is an amorphous form of carbon which resembles diamond in its hardness, lubricity, and resistance to chemical attack. Such properties make DLC of interest for use in barrier and hard coating technology. This report examines a variety of properties of DLC coatings. This includes examining substrates on which DLC coatings can be deposited; the resistance of DLC coatings to various chemical agents; adhension of DLC coatings; and characterization of DLC coatings by electro… more

Date: May 1, 1994

Creator: Outka, D. A.; Hsu, Wen L.; Phillips, K.; Boehme, D. R.; Yang, N. Y. C.; Ottesen, D. K. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Ferroelectric thin film microstructure development and related property enhancement

Factors that control phase evolution, microstructural development and ferroelectric domain assemblage are evaluated for chemically prepared lead zirconate titanate (PZT) thin films. Zirconium to titanium stoichiometry is shown to strongly influence microstructure. As Ti content increases, there is an apparent enhancement of the perovskite phase nucleation rate, grain size becomes smaller, and the amount of pyrochlore phase, if present, decreases. While the pyrochlore matrix microstructure for n… more

Date: November 1, 1993

Creator: Tuttle, B.; Voigt, J. A.; Headley, T. J.; Potter, B. G.; Dimos, D.; Schwartz, R. W. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Inorganic polymer-derived ceramic membranes

Polymeric silica sols were used to prepare membranes on commercial {gamma}-A1{sub 2}O{sub 3} supports. Aging of the silica sols was shown to be effective to form discrete membrane layers. He/N{sub 2} selectivity factors exceeding ideal Knudsen values were observed when the sols were prepared under conditions in which the condensation rate was minimized. It is proposed that the average pore size of the membrane depends on the balance of capillary pressure and modulus during membrane deposition a… more

Date: December 31, 1993

Creator: Brinker, C. J.; Sehgal, R.; Raman, N.; Schunk, P. R. & Headley, T. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

FY05 HPCRM Annual Report: High-Performance Corrosion-Resistant Iron-Based Amorphous Metal Coatings

New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative corrosion resistance. Many of these materials can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in some very aggressive environments, including concentrated calcium-chloride brines at elevated temper… more

Date: September 20, 2007

Creator: Farmer, J.; Choi, J.; Haslam, J.; Day, S.; Yang, N.; Headley, T. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department