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in subjects: "Titanium Compounds"

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Reinforcements for high temperature ceramics

A method has been investigated and developed to grow TiB{sub 2} whiskers by the VLS mechanism. The reaction was carried out in a quartz tube 3 in. in diameter, 30 in. long at about 1150{degrees}C in the presence of a catalyst. The basic experimental parameters, a substrate, and a catalyst, for the growth of the whiskers have been defined. The whiskers produced have shown variable size and morphology depending on the experimental conditions, and location of the whiskers from the input port. The … more

Date: April 1, 1992

Creator: Kyriacou, C. I.; Sepulveda, J. L. & Watson, M. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Development of large insulator rings for the TOKAMAK Fusion Test Reactor

Research and development leading to the manufacture of large ceramic insulator rings for the TFTR (TOKAMAK Fusion Test Reactor). Material applictions, fabrication approach and testing activities are highlighted.

Date: January 1, 1977

Creator: Brown, T. & Tobin, A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Magnetic Susceptibility and Proton NMR study of TiCr/sub 1/ /sub 8/H/sub x/

The electronic properties of the hexagonal (C-14) and cubic (C-15) allotropes of the TiCr/sub 1/ /sub 8/+/sub 0/ /sub 1//H/sub 2/ system have been examined via magnetic susceptibility and proton NMR studies. The results indicate an increase in N(E/sub F/), the electron density of states at the Fermi level, with increasing H/M for both allotropes; the trend extends into the ..cap alpha..'-hydride phase. The results suggest a basis for thermodynamic anomalies reported for the solution of hydrogen… more

Date: January 1, 1982

Creator: Lynch, J. F.; Johnson, J. R. & Bowman, R. C., Jr.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Multiply stripped ion generation in the metal vapor vacuum arc

We consider the charge state distribution of ions produced in the metal vapor vacuum arc plasma discharge. A new kind of high current metal ion source in which the ion beam is extracted from a metal vapor vacuum arc plasma has been used to obtain the spectra of multiply charged ions produced within the cathode spots. The cathode materials used and the species reportetd on here are: C, Mg, Al, Si, Ti, Cr, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Rh, Pd, Ag, In, Sn, Gd, Ho, Ta, W, Pt, Au, Pb, Th, and U; t… more

Date: September 1, 1987

Creator: Brown, I.G.; Feinberg, B. & Galvin, J.E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Shock compaction of a porous pyrotechnic material

The results of an experimental program to generate Hugoniot data for an unreacted pyrotechnic material are discussed and the data presented. The program included both sample fabrication and experimental determination of stress-particle velocity Hugoniot data for the pyrotechnic, titanium hydride-potassium perchlorate (TiH/sub 2/-KClO/sub 4/), at two densities. The TiH/sub 2/-KClO/sub 4/, which was supplied as a powder mixture, was pressed to the desired bulk sample density and size using a ram … more

Date: January 1, 1980

Creator: Lee, L. M. & Schwarz, A. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Reflectance of Co- and Nb-doped BaTiO/sub 3/ for photon energies from 1. 8 to 70 eV

The reflectance spectra of Co- and Nb-doped BaTiO/sub 3/ crystals have been measured for photon energies from 1.8 to 70 eV. For both types of crystal, structures observed in the 1.8 to 2.3 eV range can be attributed to the presence of residual impurities. Between 2.3 and 3.2 eV the peaks in the reflectance of the Co-doped crystal are found to be of an acceptor charge transfer type. For Nb-doped crystals structures appear at the bottom of the conduction band. For energies larger than 3.2 eV the … more

Date: January 1, 1985

Creator: Goudonnet, J.P.; Godefroy, G.; Inagaki, T.; Moretti, P.; Williams, M.W. & Arakawa, E.T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Electromagnetic energy applied to and gained from lunar materials

Electromagnetic energy may be useful in microwave frequencies for in-situ melting or sintering of lunar regolith. Simple configurations of magnetron or gyrotron tubes might be constructed for unique melting geometries. For energy production, lunar ilmenite has potential applications in photovoltaic devices. 11 refs., 11 figs.

Date: January 1, 1986

Creator: Meek, T.T.; Vaniman, D.T.; Blake, R.D. & Cocks, F.H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Development and laboratory testing of low Z refractory coatings for fusion reactor limiters

A materials development program for low Z (Z < 24) coated tokamak limiters is described. A variety of refractory coatings applied by chemical vapor deposition, plasma spraying and chemical conversion to graphite and copper substrates have been evaluated. The results of laboratory testing for low energy hydrogen ion erosion, arc erosion and thermal fatigue by pulsed electron beam heating are reported. The 250 V hydrogen ion erosion data, analysed in terms of the effect of plasma radiation losses… more

Date: January 1, 1980

Creator: Mullendore, A. W.; Whitley, J. B. & Mattox, D. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Effect of carbon on ion beam mixing of Fe-Ti bilayers

The influence of implanted carbon on ion beam mixing of a Fe-Ti system was investigated. Carbon was introduced into bilayer samples by implanting {sup 13}C isotopes. The implantation energies were selected to set the mean range of carbon ions in either the iron or titanium layer. The effect of implanted carbon on 400 keV Ar ion mixing in the temperature range from 0 to 300{degree}C was studied using Rutherford backscattering spectroscopy at the energy of 5 MeV. Changes in carbon concentration p… more

Date: January 1, 1989

Creator: Hirvonen, J.P.; Nastasi, M.; Lappalainen, R.; Sickafus, K. (Los Alamos National Lab., NM (USA); Physics, Helsinki Univ. (Finland). Dept. of & Los Alamos National Lab., NM (USA))

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Transient stress evolution and crystallization in laser-irradiated amorphous titania sol-gel films

Amorphous TiO{sub 2} sol-gel films are irreversibly transformed to a crystalline anatase phase when heated to temperatures in excess of 575 K or subjected to intense pulsed or CW laser irradiation. The laser-induced transformation is initiated as a result of impurity absorption and subsequent heating, and results in densification and relative changes in compressive stress of the film. Isothermally annealed films exhibit a decrease in compressive stress as crystallization proceeds while an incre… more

Date: October 1, 1991

Creator: Exarhos, G.J.; Hess, N.J. (Pacific Northwest Lab., Richland, WA (United States)) & Wood, S. (Washington State Univ., Pullman, WA (United States). Dept. of Physics)

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Optimization of glass composition for the vitrification of nuclear waste at the Savannah River Plant

Waste glasses of different compositions were compared in terms of leachability, viscosity, liquidus temperature, and coefficient of expansion. The compositions of the glasses were determined by statistical optimization. Waste glass of the optimized composition is more durable than the current reference composition but can still be processed at low temperature.

Date: January 1, 1982

Creator: Soper, P. D.; Roberts, G. J.; Lightner, L. F.; Walker, D. D. & Plodinec, M. J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Release of H and He from TiC, stainless steel and graphite by pulsed electron and furnace heating

The release of implanted D and /sup 3/He from TiC coatings, SS 304 and graphite by pulsed electron beam (e-beam) heating and furnace heating has been investigated. Low fluence implants of D or /sup 3/He and saturation fluence D implants have been studied for 0.5 - 1.5 keV D and 3 keV /sup 3/He. The retained D or /sup 3/He was monitored by ion beam analysis. The 50 ns e-beam pulsing resulted in the release of D in all materials and was compared with release during isochronal annealing in a furna… more

Date: January 1, 1980

Creator: Picraux, S.T. & Wampler, W.R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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The domain structure features of epitaxial PbTiO sub 3 thin films prepared by MOCVD

Ferroelectric oxide thin films have attracted great interest in recent years because of their potential applications in numerous electro-optic, pyroelectric, acousto-optical, and nonvolatile memory devices, and a variety of methods such as sputtering, laser ablation, and MOCVD has been used for preparation of the films. Among these ferroelectric materials, the PbTiO{sub 3} thin film has been extensively studied because of its small dielectric constant, large spontaneous polarization, small coer… more

Date: March 1, 1992

Creator: Bai, G.R.; Chang, H.L.M.; Foster, C.M. & Lam, D.J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Leaching behavior of glass ceramic nuclear waste forms

Glass ceramic waste forms have been investigated as alternatives to borosilicate glasses for the immobilization of high-level radioactive waste at Pacific Northwest Laboratory (PNL). Three glass ceramic systems were investigated, including basalt, celsian, and fresnoite, each containing 20 wt % simulated high-level waste calcine. Static leach tests were performed on seven glass ceramic materials and one parent glass (before recrystallization). Samples were leached at 90/sup 0/C for 3 to 28 days… more

Date: November 1, 1981

Creator: Lokken, R.O.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Structure and properties of nanophase TiO/sub 2/

Ultrafine-grained, nanophase samples of TiO/sub 2/ (rutile) were synthesized by the gas-condensation method and subsequent in-situ compaction, and then studied by transmission electron microscopy, Vickers hardness measurements, and positron annihilation spectroscopy as a function of sintering temperature. The nanophase compacts densified rapidly above 500/sup 0/C, with only a small increase in grain size. The hardness values obtained by this method are comparable to or greater than coarser-grai… more

Date: July 1, 1987

Creator: Siegel, R.W.; Hahn, H.; Ramasamy, S.; Zongquan, Li; Ting, Lu & Gronsky, R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Relative radiation sensitivity of insulators, stabilizers, and superconductors

The objective of this work was to compare the radiation sensitivity of the various parts of superconducting magnet systems. Using the radiation spectra calculated by Engholm for the Engineering Test Facility (ETF) toroidal field magnet inboard leg and available data on radiation effects, commonly used magnet components were ranked in order of radiation sensitivity. It was found that epoxy-based insulators and copper and aluminum stabilizers were the most sensitive parts of the magnets, more sen… more

Date: January 15, 1982

Creator: Van Konynenburg, R.A. & Guinan, M.W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Negative Ion Sources Equipped With Continuous Annular and Spherical Geometry Surface Ionizers

Axial geometry negative ion sources have been designed, developed, and evaluated for use in conjunction with tandem accelerator applications. These sources utilize continuous surface solid tungsten ionizers in either annular or spherical geometries to effect ionization of cesium vapor, which in turn is used to sputter a negatively biased probe containing the material of interest. The annular ionizer geometry source has been incorporated as an ''on-line'' source for routine operation of the Holi… more

Date: January 1, 1985

Creator: Alton, G. D. & Mills, G. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Rolling-contact and wear resistance of hard coatings on bearing-steel substrates

Ever-increasing needs for high-performance ball- and roller-bearing components that can endure extreme applications have led to a growing interest in hard coatings for improved fatigue life and wear resistance. In particular, hard TiN and TiC coatings and, quite recently, diamond like carbon films have attracted much attention from manufacturers that produce bearing systems for both rolling- and sliding-contact applications. This paper presents an overview that highlights recent incremental pro… more

Date: February 1, 1992

Creator: Erdemir, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Intergranular and interphase boundaries in ceramics

Interfaces are of great importance in both electronic and structural ceramics. The microstructure and microchemistry of interfaces can be studied by transmission electron microscopy, both high resolution and analytical. Examples are taken from both intergranular and interphase boundaries in ceramics. The former include low angle, twin and 90/degree/ boundaries in YBa/sub 2/Cu/sub 3/O/sub 7/ superconductors. Interphase boundaries include epitactic layers of YBa/sub 2/Cu/sub 3/O/sub 7/on SrTiO/su… more

Date: January 1, 1989

Creator: Mitchell, T.E.; Roy, T. & Unal, O.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Nanophase materials assembled from atomic clusters

The preparation of atomic clusters of metals and ceramics by means of the gas-condensation method, followed by their in situ consolidation under high-vacuum conditions, has recently led to the synthesis of a new class of ultrafine-grained materials for which their physics is intimately coupled with their application. These nanophase materials, with 2 to 20 nm grain sizes, appear to have properties that are often rather different from conventional materials, and also processing characteristics t… more

Date: September 1, 1989

Creator: Siegel, R. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Investigation of the processes controlling the flame generation of refractory materials

The processes involved in the formation of mixed oxides powders were studied using the counterflow diffusion flame burner. Powders of different morphologies were obtained by varying the flame conditions (temperature, residence time) and the concentration ratio of the oxides precursors. In-situ particle size and number density were determined using dynamic light scattering and 90{degrees} light scattering. A thermophoretic sampling method and a larger scale powder collection device also was used… more

Date: January 1, 1992

Creator: Katz, J. L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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General Chemistry Division. Quarterly report, October-December 1979

Progress is reported on analytical R and D for the nuclear explosives programs (coupling of gas chromatograph, mass spectrometer, and infrared spectrometer; analysis of fluorocarbon FC-86; far-infrared laser development; transient behavior of n-type TiO/sub 2/ semiconductor photoelectrodes; and impurities on Kevlar 49 fibers) and for the energy programs (on-line mass spectroscopy of oil shale and testing of additives for controlling the scaling of hypersaline geothermal brine). (DLC)

Date: February 15, 1980

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Development of high temperature, high pressure rotating shaft seals: Final report

Rotating shaft seals used in coal gasification equipment are exposed to difficult environmental conditions including temperature from 430/sup 0/C to 816/sup 0/C (800/sup 0/F to 1500/sup 0/F), high pressure (to 10 MPa or 1500 psig), and high levels of particulate contamination (50,000 to 100,000 ppM). The program reported upon was designed to develop long-life seals that would not require external flushing or cooling. The approach taken was to develop unbalanced face that would remain closed and… more

Date: June 1, 1987

Creator: Heshmat, H. & Shapiro, W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Strong fibers

This program was directed to a new and generic approach to the development of new materials with novel and interesting properties, and to the precision fabrication of these materials in one and two-dimensional forms. Advanced deposition processes and microfabrication technology were used to produce fibers and grids of metals, semiconductors, ceramics, and mixtures of controlled composition and structure, and with new and interesting mechanical and physical properties. Deposition processes inclu… more

Date: March 1, 1991

Creator: Li, Che-Yu.

Item Type: Report

Partner: UNT Libraries Government Documents Department