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Protective Coatings for Molybdenum

Description: Report discussing studies on various types of protective coatings for a molybdenum sheet. Procedures, materials, and results of each coating are included.
Date: February 17, 1953
Creator: Powell, Carroll F.; Jones, R. P.; Secrest, A. C.; Sherwood, E. M. & Campbell, Ivor E.
Partner: UNT Libraries Government Documents Department

Corrosion in 650 F Degassed Water of Uranium-Molybdenum Alloys Containing Impurity Additions

Description: From introduction: "At the request of WAPD, a study has been made of the effect of minor compositional variables on the corrosion behavior of uranium-molybdenum alloys in 650 F degassed water."
Date: October 6, 1955
Creator: Cawthorne, Edward W.; Berry, Warren E., 1922-; Reynolds, James E.; Jaffee, Robert Isaac, 1917- & Peoples, Robert S.
Partner: UNT Libraries Government Documents Department

Advances in the reduction and compensation of film stress in high-reflectance multilayer coatings for extreme ultraviolet lithography applications

Description: Due to the stringent surface figure requirements for the multilayer-coated optics in an extreme ultraviolet (EUV) projection lithography system, it is desirable to minimize deformation due to the multilayer film stress. However, the stress must be reduced or compensated without reducing EUV reflectivity, since the reflectivity has a strong impact on the throughput of a EUV lithography tool. In this work we identify and evaluate several leading techniques for stress reduction and compensation as applied to Mo/Si and Mo/Be multilayer films. The measured film stress for Mo/Si films with EUV reflectances near 67.4% at 13.4 nm is approximately - 420 MPa (compressive), while it is approximately +330 MPa (tensile) for Mo/Be films with EUV reflectances near 69.4% at 11.4 nm. Varying the Mo-to-Si ratio can be used to reduce the stress to near zero levels, but at a large loss in EUV reflectance (> 20%). The technique of varying the base pressure (impurity level) yielded a 10% decrease in stress with a 2% decrease in reflectance for our multilayers. Post-deposition annealing was performed and it was observed that while the cost in reflectance is relatively high (3.5%) to bring the stress to near zero levels (i.e., reduce by 1 00%), the stress can be reduced by 75% with only a 1.3% drop in reflectivity at annealing temperatures near 200{degrees}C. A study of annealing during Mo/Si deposition was also performed; however, no practical advantage was observed by heating during deposition. A new non-thermal (athermal) buffer-layer technique was developed to compensate for the effects of stress. Using this technique with amorphous silicon and Mo/Be buffer-layers it was possible to obtain Mo/Be and Mo/Si multilayer films with a near zero net film stress and less than a 1% loss in reflectivity. For example a Mo/Be film with 68.7% reflectivity at 11.4 nm and ...
Date: February 20, 1998
Creator: Mirkarimi, P.B., LLNL
Partner: UNT Libraries Government Documents Department

Effect of Mo on pitting corrosion of ferritic steels in bromide and chloride solutions

Description: A model for pitting corrosion of stainless steels, independent of changes of passive film properties, was tested using Fe-18%Cr-x%Mo alloys in bromide and chlorine solutions. In 1M LiCl the pitting potential improved from {minus}50 mV{sub sce} to about 1200 mV{sub sce} on increasing Mo from 2% to 10%. In 1M LiBr the pitting potential increased from 125 to only 560 mV{sub sce}. Active dissolution kinetics of these steels in saturated solutions in a simulated pit were measured. Tafel lines for dissolution moved to more noble potentials with increases in Mo, indicating Mo inhibited dissolution rates. The potential increases were found to be equal to the increases in pitting potential for both halides. Agreement was interpreted in terms maintaining high halide concentrations in the pit by high rates of active metal dissolution. Bromide was less effective suggesting it interacted with Mo adsorbed on the dissolving surface.
Date: December 1, 1997
Creator: Kaneko, M. & Isaacs, H.S.
Partner: UNT Libraries Government Documents Department

Electronic effects at interfaces in Cu-Cr, Mo, W, Ta, Re multilayers

Description: Interfacial electronic effects between Cu and the transition metals Cr, Mo, W, Ta, Re, are investigated by determining the strength of the white line absorption resonances on the L,,, edges of Cu in Cu{sub 5}/TM{sub 5} multilayers. X-ray absorption (XAS) was performed to study the white lines, which are directly related to the unoccupied states of Cu in the multilayers. The metallic multilayers are 2 mn in period and 200 mn in total thickness. Each period contains 5 monolayers of Cu and 5 monolayers of the transition metal: 40% of the atoms are at interfaces. These material pairs form ideal structures for the investigation of interfacial electronic effects as they form no compounds and exhibit terminal solid solubility. Only weak white lines are observed on the L3,2 edges of Cu since all the d-orbitals are filled. In the Cu/TM multilayers, however, we observed enhancement of the Cu white lines. We attribute this to the charge transfer from the `interfacial Cu atoms` d-orbital to the transition metal layers. Analysis of the white line enhancement enables calculation of the charge transfer from the Cu to the transition metal. Cu shows a charge transfer of about 0.03 electrons/interfacial Cu atom in Cu/Cr, 0.064 in Cu/Mo, 2048 0.35 in Cu/Ta, 0.17 in Cu/W , and 0.23 in Cu/Re. This charge transfer is consistent with the enhanced absorption energy of Cu on these materials as observed in thermal desorption experiments.
Date: April 1, 1998
Creator: Bello, A.F.; Van Buuren, T.; Kepesis, J.E. & Barbee, T.W., Jr.
Partner: UNT Libraries Government Documents Department


Description: The time-dependent behavior was investigated of the neutron population in an unreflected unmoderated cylindrical assembly of 90 wt.% U (93.2 wt.% U/sup 235/), 10 wt.% Mo alloy following rapid establishment of a super-prompt critical c ondition with negligible initial neutron population. Reactivity increases up to 11 cents above prompt critical resulted in bursts yielding as many as 1.8 x 10/ sup 17/ fissions with reactor periods as short as 16 mu sec and temperature increases as large as 400 deg C. Pressure waves generated in a portion of the core held in position by an electromagnet for bursts greater than ~6 x 10/sup 16/ fissions initiated the removal of this section about 225 mu sec after the peak burst. (auth)
Date: May 10, 1962
Creator: Mihalczo, J.T.
Partner: UNT Libraries Government Documents Department


Description: The purpose of this memorandum is to summarize the present state of development of iron-- aluminum-base alloys. The binary iron--aluminum alloys offer favorable tensile strength but possess very poor ductility. The iron-- aluminum -- molybdenum alloy, thermenol (Fe -16A1--3 Mo), is corrosion resistant, offers excellent tensile strength, and is ductile. (A.C.)
Date: November 18, 1957
Creator: Lepkowski, W.J. & Holladay, J.W.
Partner: UNT Libraries Government Documents Department

U-10 Wt % Mo Fuel Element: Irradiation in SRE

Description: From abstract: The fuel element assembly was successfully irradiated in the SRE to a maximum burnup of 5300 Mwd/MTU, at a peak fission rate of approximately 1.5 x 10E13 fissions/cm3-sec and a maximum central temperature near 1200F.
Date: August 31, 1965
Creator: Arnold, J. L.; Miller, K. J. & Peterson, R. M.
Partner: UNT Libraries Government Documents Department

In-situ Fracture Studies and Modeling of the Toughening Mechanism Present in Wrought LCAC, TZM, and ODS Molybdenum Flat Products

Description: In-situ testing, ultrasonic C-scans, and metallography were used to show that a crack-divider delamination form of thin-sheet toughening occurs in wrought Low Carbon Arc Cast (LCAC) unalloyed molybdenum, Oxide Dispersion Strengthened (ODS) molybdenum, and TZM molybdenum at temperatures {ge} the Ductile to Brittle Transition Temperature (DBTT). Cracking along boundaries relieves mechanical constraint to free ligaments that may plastically stretch to produce toughening. Anisotropy in fracture toughness with lower values in the short-transverse direction is shown to produce the crack divider delaminations at the crack tip in the LT and TL orientations. The delamination zone increases with increasing stress-intensity to sizes significantly larger than the plastic zone, which leads to large increases in fracture toughness by the thin sheet toughening mechanism. Fracture in ODS Mo-alloys proceeds mainly along grain boundaries to produce small ligaments that exhibit ductility for both LT and TL orientations resulting in a lower DBTT and higher toughness values at lower temperatures than observed in LCAC and TZM. A combination of grain boundary fracture and cleavage is prevalent in LCAC molybdenum and TZM. The predominance for microcracking along grain boundaries to leave fine, ductile ligaments in ODS molybdenum can be attributed to a fine-grained microstructure with {approx} 1-2 {micro}m thickness of sheet-like grains. The presence of mixed grain boundary fracture and cleavage in LCAC and TZM can be attributed to a microstructure with a larger thickness of sheet-like grains (4-15 {micro}m).
Date: July 1, 2007
Creator: Cockerman, B. V. and Chan, K. S.
Partner: UNT Libraries Government Documents Department

The history of development of molybdenum alloys for structural applications

Description: Molybdenum was first isolated as an element in 1893 and found initial commercial application as a filament support for incandescent lamps in 1910. The advent of arc melting practice in the 1940s led to an increase in availability of Mo sheet, bar, and plate products. Alloy development programs were heavily supported starting in the 1950s and several key alloys emerged over the next twenty years that remain in use to the present time such as Mo-TZM, unalloyed Mo, and Mo-Re. In recent years, improved understanding of the role of oxygen and carbide distributions at grain boundaries have led to increased reliability and use of Mo in aerospace products. Current developmental programs in areas of propulsion and energy conversion will ensure the prominent position of Mo as a high-temperature structural material. This paper highlights some of these key developments in the evolution of Mo alloys.
Date: February 1, 1993
Creator: Wadsworth, J. & Wittenauer, J. P.
Partner: UNT Libraries Government Documents Department

Oxide strengthened molybdenum-rhenium alloy

Description: Provided is a method of making an ODS molybdenum-rhenium alloy which includes the steps of: (1) forming a slurry containing molybdenum oxide and a metal salt dispersed in an aqueous medium, the metal salt being selected from nitrates or acetates of lanthanum, cerium or thorium; (2) heating the slurry in the presence of hydrogen to form a molybdenum powder comprising molybdenum and an oxide of the metal salt; (3) mixing rhenium powder with the molybdenum powder to form a molybdenum-rhenium powder; (4) pressing the molybdenum-rhenium powder to form a molybdenum-rhenium compact; (5) sintering the molybdenum-rhenium compact in hydrogen or under a vacuum to form a molybdenum-rhenium ingot; and (6) compacting the molybdenum-rhenium ingot to reduce the cross-sectional area of the molybdenum-rhenium ingot and form a molybdenum-rhenium alloy containing said metal oxide. The present invention also provides an ODS molybdenum-rhenium alloy made by the method.
Date: December 1, 1998
Creator: Bianco, Robert & Buckman, William R. Jr.
Partner: UNT Libraries Government Documents Department

Alloys of Uranium with Zirconium, Chromium, Columbium, Vanadium, and Molybdenum

Description: Abstract: Information on five uranium binary alloy systems has been surveyed. These systems are the alloys of uranium with zirconium, chromium, columbium, vanadium, and molybdenum. The equilibrium diagrams are discussed, and where available, data have been included on diffusion studies, cladding experiments, and mechanical properties.
Date: June 19, 1952
Creator: Saller, Henry A. & Rough, Frank A.
Partner: UNT Libraries Government Documents Department

The potential pyrophoricity of BMI-SPEC and aluminum plate spent fuels retrieved from underwater storage

Description: Physical/chemical factors in U metal and hydride combustion, particularly pyrophoricity in ambient environment, were evaluated for BMI-SPEC and UAl{sub x} plate fuels. Some metal fuels may be highly reactive (spontaneously igniting in air) due to high specific surface area, high decay heat, or a high U hydride content from corrosion during underwater storage. However, for the BMI-SPEC and the aluminum plate fuels, this reactivity is too low to present a realistic threat of uncontrolled spontaneous combustion at ambient conditions. While residual U hydride is expected in these corroded fuels, the hydride levels are expected to be too low and the configuration too unfavorable to ignite the fuel meat when the fuels are retrieved from the basin and dried. Furthermore the composition and microstructure of the UAl{sub x} fuels further mitigate that risk.
Date: August 1996
Creator: Ebner, M. A.
Partner: UNT Libraries Government Documents Department