Structural investigation of B{sup +} ion implantation induced amorphization in polycrystalline Ni thin films

Structural investigation of B{sup +} ion implantation induced amorphization in polycrystalline Ni thin films

Date: June 1, 1996
Creator: Liu, P.C.; Zaluzec, N.J.; Okamoto, P.R. & Meshii, M.
Description: High fluence metalloid ion implantation have been shown to induce amorphous phase formation in transition metals systems. In this study, electron energy loss spectroscopy and energy filtered selective area electron diffraction have been used along with conventional TEM to characterize the structural and electronic changes resulting from B{sup +} ion implantation into polycrystalline Ni thin films.
Contributing Partner: UNT Libraries Government Documents Department
Crystal and magnetic structure of stoichiometric YFe{sub 2}O{sub 4}

Crystal and magnetic structure of stoichiometric YFe{sub 2}O{sub 4}

Date: August 1, 1994
Creator: Katano, S.; Funahashi, S.; Matsumoto, T.; Iida, J.; Tanaka, M. & Cable, J.W.
Description: Crystal structure of stoichiometric YFe{sub 2}O{sub 4} powder was studied by high-resolution neutron diffraction at room temperature, 225 K and 80 K. Rietveld refinements of the diffraction patterns give reasonable fits with space group R{bar 3}m (hexagonal) for room temperature, and with P{bar 1} (triclinic) for 225 K. However, the 80 K pattern cannot be fitted at all with the same triclinic symmetry, indicating that the structure is much more complicated. The magnetic reflection has been separated from those complex nuclear peaks by the polarization analysis. The magnetic structure is also fairly complicated both at 225 K and at 80 K.
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Analytical electron microscopy of rapidly solidified metals

Analytical electron microscopy of rapidly solidified metals

Date: December 31, 1991
Creator: Kelly, T.F.; Holzman, L.M.; Shin, K.; Kim, Y.W.; Bae, J.C.; Flinn, J.E. et al.
Description: Examples of the need to characterize rapidly solidified metals on submicron scale are given for centrifugally atomized steel powder and electrohydrodynamically atomized submicron spheres. Materials studied include Fe-40wt% Ni, 304 SS, Fe-20at.%Co, and pure V.
Contributing Partner: UNT Libraries Government Documents Department
Continued study of the effects of heat treatment and microstructure on electrocatalyst performance. Final report, July 29, 1991--December 20, 1991

Continued study of the effects of heat treatment and microstructure on electrocatalyst performance. Final report, July 29, 1991--December 20, 1991

Date: February 1, 1992
Creator: Stoner, G.E.
Description: Platinum and platinum-chromium bulk electrodes were analyzed in 100 wt.% H{sub 3}PO{sub 4} at 200{degrees} C to evaluate the kinetics for the oxygen reduction reaction (ORR) in the phosphoric acid fuel cell (PAFC) operating environment. Dispersed platinum and platinum-chromium catalyst electrodes were operated potentiostatically under simulated PAFC operating conditions (0.7 V vs. RHE in 100 wt.% H{sub 3}PO{sub 4} at 200{degrees} C) using the submerged mode to evaluate the degradation mechanism. Differences observed between the hanging meniscus rotating disk (HMRD) electrode and the rotating disk electrode (RDE) method were related to the different hydrodynamics present in the hanging meniscus. The boundary conditions applicable to an infinite rotating disk are no longer present. The most probable cause for the observed differences is that the surface of the HMRD electrode is no longer uniformly accessible with respect to the diffusing species. Therefore, the kinetic data extracted from the mixed control conditions are altered sufficiently so that precise potential-current curves cannot be obtained. However, the data obtained are highly reproducible. Therefore, the method appears suitable for determining comparative kinetic data for platinum and platinum-chromium at 200 a C in 100 wt.% H{sub 3}PO{sub 4}, where RDE designs will not function. Cyclic voltammetry conducted ...
Contributing Partner: UNT Libraries Government Documents Department
A mass spectrometric analysis of {gamma}-GPS films

A mass spectrometric analysis of {gamma}-GPS films

Date: June 1, 1996
Creator: Dillingham, R.G.; Boerio, F.J.; Bertelsen, C.; Savina, M.R.; Lykke, K.R. & Calaway, W.F.
Description: {gamma}-glycidoxypropyltrimethoxysilane ({gamma}-GPS) is used for pre-treatment of grit-blasted aluminum before adhesive bonding. This paper discusses analysis of non-reflective grit-blasted surfaces using mass spectrometry of species that were either sputtered off using an ion beam or thermally desorbed as neutrals using a pulsed laser and then post-ionized using a secondary laser. Results show that fragmentation is excessive and structural information is difficult to obtain from the spectra.
Contributing Partner: UNT Libraries Government Documents Department
The Correlation of Stress-State and Nano-Mechanical Properties in Au

The Correlation of Stress-State and Nano-Mechanical Properties in Au

Date: October 7, 1999
Creator: HOUSTON,JACK E.; JARAUSCH,K.F.; KIELY,J.D. & RUSSELL,P.E.
Description: A dependence of elastic response on the stress-state of a thin film has been demonstrated using the interfacial force microscope (IFM). Indentation response was measured as a function of the applied biaxial stress-state for 100 nm thick Au films. An increase in measured elastic modulus with applied compressive stress, and a decrease with applied tensile stress was observed. Measurements of elastic modulus before and after applying stress were identical indicating that the observed change in response is not due to a permanent change in film properties.
Contributing Partner: UNT Libraries Government Documents Department
Direct correlation of transport properties and microstructure in Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-x} thin film grain boundaries

Direct correlation of transport properties and microstructure in Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-x} thin film grain boundaries

Date: July 1, 1995
Creator: Vuchic, B.V.; Merkle, K.L.; Buchholz, D.B.; Chang, R.P.H. & Marks, L.D.
Description: Individual 45{degrees} [0011] tilt grain boundaries in Y{sub l}Ba{sub 2}Cu{sub 3}O{sub 7{minus}x} thin films grown on biepitaxial substrates were studied. The thin films were grown using both pulsed organometallic beam epitaxy (POMBE) and laser ablation. Transport characteristics of the individual grain boundaries were measured including resistance -- temperature (R-T) and current -- voltage (I-V) dependencies with and without an applied magnetic field. In order to elucidate possible structural origins of the differences in transport behavior, the same grain boundaries which were electrically characterized were subsequently thinned for electron-microscopy analysis. Transmission-electron-microscopy and high-resolution-electron-microscopy were used to structurally characterize the grain boundaries. The macroscopic and microscopic structures of two boundaries, a nominally resistive and a superconducting grain boundary, are compared. Work supported by the National Science Foundation Office of Science and Technology Centers, under contract {number_sign}DMR 91-20000 (BVV, DBB) and the US Department of Energy, Basic Energy Sciences-Materials Science, under contract {number_sign}W-31-109-EN(S-38 (KLM).
Contributing Partner: UNT Libraries Government Documents Department
Structure factor measurement in TiAl and silicon

Structure factor measurement in TiAl and silicon

Date: March 1, 1996
Creator: Swaminathan, S.; Wiezorek, J.M.; Jones, I.P.; Zaluzec, N.J.; Fraser & Maher, D.M.
Description: It proved impossible to obtain results with sufficient precision for TiAl reproducibly (<0.1%) from samples of different thicknesses. In order to ascertain the origin of this inconsistency, this study concentrates on the development of the experimental and theoretical tools required for such refinement and measurements for Si have been performed.
Contributing Partner: UNT Libraries Government Documents Department
Comparison of the crevice corrosion resistance of alloys 625 and 22

Comparison of the crevice corrosion resistance of alloys 625 and 22

Date: September 15, 1999
Creator: Palmer, J; Kehler, B; Iloybare, G O & Scully, J R
Description: The Yucca Mountain Site Characterization Project is concerned with the corrosion resistance of candidate engineered waste package materials. A variety of waste package designs have been proposed for US and Canadian High Level Nuclear Waste Repositories. A common feature of each design is the possibility of utilizing a corrosion resistant material such as a nickel-based super alloy or titanium-based alloy. A suitable corrosion resistant material may provide (a) kinetic immunity if the combination of repository environmental conditions and alloy resistance assure both: (i) a passive condition with negligible chance of localized corrosion stabilization, as well as (ii) low enough passive dissolution rates to insure conventional corrosion allowance over geological times, (b) a second form of ''corrosion allowance,'' if it can be scientifically demonstrated that a mechanism for stifling (i.e., death) of localized corrosion propagation occurs well before waste canisters are penetrated, or (c) such a low probability of initiation and continued propagation that a tolerably low degree of penetration occurs. Unfortunately, a large database on the crevice corrosion properties of alloy 22 does not exist in comparison to alloy 625. Alloy screening tests in oxidizing acids containing FeCl3 indicate that alloy 22 is more resistant to crevice corrosion than 625 ...
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Materials sciences programs: Fiscal year 1995

Materials sciences programs: Fiscal year 1995

Date: May 1, 1996
Creator: unknown
Description: The purpose of this report is to provide a convenient compilation and index of the DOE Materials Science Division programs. This compilation is primarily intended for use by administrators, managers, and scientists to help coordinate research. The report is divided into eight sections. Section A contains all Laboratory projects, Section B has all contract research projects, Section C has projects funded under the Small Business Innovation Research Program, Section D describes the Center of Excellence for the Synthesis and Processing of Advanced Materials and E has information on major user facilities. F describes other user facilities, G as a summary of funding levels and H has indices characterizing research projects.
Contributing Partner: UNT Libraries Government Documents Department
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