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High-field magnetization studies of U{sub 2}T{sub 2}Sn (T=Co, Ir, Pt) compounds

Description: High-field magnetization measurements at 4.2 K on U{sub 2}T{sub 2}Sn (T = Co, Ir and Pt) compounds have been performed on free and fixed powders up to 57 T. An antiferromagnetic ground state of U{sub 2}Pt{sub 2}Sn is corroborated by a metamagnetic transition at 22 T with very small hysteresis going up and down with field. U{sub 2}Co{sub 2}Sn and U{sub 2}Ir{sub 2}Sn show no metamagnetic transition up to 57 T which is in agreement with the non-magnetic ground state of these compounds. In all cases, the maximum applied field is not sufficient to achieve saturation. The short-pulse measurements presented here are compared with previous results obtained in quasi-static fields up to 35 T.
Date: July 1, 1995
Creator: Prokes, K.; Nakotte, H. & de Boer, F.R.
Partner: UNT Libraries Government Documents Department

Corrosion-resistant iridium-platinum anode material for high polarization application in corrosive acids

Description: The present invention relates to highly corrosion resistant components for use in an electrochemical cell. Specifically, these components are resistant to corrosion under very extreme conditions such as exposure to aqua regia in the presence of a constant current density of 100mA/m{sup 2}. The components are comprised of an iridium-platinum alloy that comprises less than 30% iridium. In a preferred embodiment of the present invention, the iridium-platinum alloy comprises 15-20% iridium. In another preferred embodiment of the present invention, the iridium-platinum alloy is deposited on the surface of an electrochemical cell component by magnetron sputtering. The present invention also relates to a method for conducting an electrochemical reaction in the presence of highly corrosive acids under a high degree of polarization wherein the electrochemical cell comprises a component, preferably the anode, containing an iridium-platinum alloy that comprises less than 30% iridium.
Date: September 8, 1993
Creator: Farmer, J.; Summers, L. & Lewis, P.
Partner: UNT Libraries Government Documents Department

Plastic Straining of Iridium Alloy DOP-26 During Cup Sizing Operations

Description: DOP-26 iridium alloy cups are used for fuel cladding for radioisotope power systems. The cups are deep drawn and recrystallized prior to final fabrication operations. This study characterizes the plastic deformation of cups during a sizing operation following the recrystallization heat treatment. The purpose of the sizing operation is to achieve the specified roundness, diameter, and radius dimensions of the cup. The operation introduces various levels of plastic strain in the cup. Plastic strain can be a cause of inhomogeneous or abnormal grain growth during subsequent exposure to elevated temperature during the service life of the fueled clad. This is particularly true in the case of cups which have irregularities in the cup walls from the deep drawing operations. Diameter and roundness measurements were made on two cups both before and after sizing. Plastic strain levels were calculated using the ABAQUSTM finite element software. The calculated plastic strain levels in both cups were below 0.025, a value shown to be below the critical strain for abnormal grain growth during a simulated service exposure. The calculated maximum plastic strain was found to increase with increased applied sizing load and was not sensitive to the input value for the clearance between the cup and the sizing die. The calculated geometry of the sized cups was in good agreement with the measurements on the finished cups.
Date: September 1, 2007
Creator: Ohriner, Evan Keith; Ulrich, George B & Sabau, Adrian S
Partner: UNT Libraries Government Documents Department

Annual Technical Progress Report of Radioisotope Power System Materials Production and Technology Program Tasks for October 1, 2004 Through September 30, 2005

Description: The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2005. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new radioisotope power systems.
Date: June 1, 2006
Creator: King, James F
Partner: UNT Libraries Government Documents Department

Annual Technical Progress Report of Radioisotope Power System Materials Production and Technology Program Tasks for October 1, 2005 Through September 30, 2006

Description: The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2006. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new radioisotope power systems.
Date: April 1, 2007
Creator: King, James F.
Partner: UNT Libraries Government Documents Department

Annual Technical Progress Report of Radioisotope Power Systems Materials Production and Technology Program Tasks for October 1, 2006 Through September 30, 2007

Description: The Office of Radioisotope Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Radioisotope Power Systems for fiscal year (FY) 2007. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new radioisotope power systems.
Date: April 1, 2008
Creator: King, James F
Partner: UNT Libraries Government Documents Department

Annual Technical Progress Report of Radioisotope Power Systems Materials Production and Technology Program Tasks for October 1, 2007 Through September 30,2008

Description: The Office of Radioisotope Power Systems (RPS) of the Department of Energy (DOE) provides RPS for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration (NASA) for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of RPS for fiscal year (FY) 2008. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new RPS.
Date: April 1, 2009
Creator: King, James F
Partner: UNT Libraries Government Documents Department

Annual Technical Progress Report of the Radioisotope Power Systems Materials Production and Technology Program Tasks for October 1, 2008 through September 30, 2009

Description: The Office of Space and Defense Power Systems of the U. S. Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators (RTG) were supplied by the DOE to the National Aeronautics and Space Administration (NASA) for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, the Oak Ridge National Laboratory (ORNL) produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. ORNL has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2009. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new RPS.
Date: May 1, 2010
Creator: King, James F
Partner: UNT Libraries Government Documents Department

Rhenium and iridium

Description: Re is used together with Ir in a number of metallurgical applications. Ir has been used as coating for Re rocket thrusters and as an oxidation-resistant coating in a number of other applications. The high strength of Re at elevated temperature is combined with the oxidation resistance and high melting point of Ir. The use of the two metals together is advantageous due to absence of stable intermetallic compounds. Both Re and Ir alloying additions improve the ductility of W. The high solubility of Re in Ir is also taken advantage of to produce Ir-based alloys for structural applications. Uses of Re in conjunction with Ir are discussed.
Date: February 1, 1997
Creator: Ohriner, E.K.
Partner: UNT Libraries Government Documents Department

A study of Mo-V and Mo-V-Fe alloys for conductive cermet applications

Description: Molybdenum and alumina cermets are currently being used for small, simple geometry, electrical feed-throughs in insulating alumina ceramic bodies. However, with larger and more complex geometries, high residual stresses and cracking of the alumina ceramic occur due to differences in coefficient of thermal expansion (CTE) between cermet and the surrounding 94% alumina. The difference in CTE is caused by the Mo in the cermet, which lowers the CTE of the cermet relative to the 94% alumina ceramic. A study was conducted at Sandia National Laboratories to develop CTE-matched cermets based on binary Mo-V and ternary Mo-V-X alloy systems. It was found that the CTE of 94% alumina (over the range 1,000 C to room temperature) could be precisely matched by a binary Mo-32.5V alloy. However, to address concerns regarding the selective oxidation of V, Mo-V-X alloys with CTE`s similar to 94% alumina were made with Fe or Co additions. The ternary additions are limited to about 3 wt.% to maintain a single phase BCC alloy, and permit some reduction in the V addition. Powders were fabricated from both Mo-27V and Mo-22V-3Fe, and were evaluated in 3 hr./1,625 C cermet sintering trials. The results of those trials suggest that extensive reaction occurs between the Vanadium component of the alloy and the alumina ceramic. In view of these results the authors have begun to evaluate the feasibility of fabricating Iridium alumina cermets. Iridium is an attractive choice due to its close CTE match to 94% alumina ceramic. Preliminary results indicate there is no detrimental reaction between the Iridium and alumina phases.
Date: June 1, 1998
Creator: Stephens, J.J.; Damkroger, B.K.; Ewsuk, K.G.; Glass, S.J.; Monroe, S.L.; Reece, M. et al.
Partner: UNT Libraries Government Documents Department

Thermoelectric material development. Quarterly technical progress report, January 1, 1995--March 31, 1995

Description: We have found that there is a limited range of solid solutions between the skutterudite compounds CoSb{sub 3} and RuSb{sub 2}Te (about 5% on each side). For the system (RuSb{sub 2}Te){sub x}(CoSb{sub 3}){sub 1-x}, preliminary results obtained on one n-type sample on the CoSb{sub 3}-rich side show that these alloys have good thermoelectric properties and a maximum ZT of about 0.89 was obtained at about 600 C. More experiments will be started to investigate the possibility of a broader range of miscibility in this system which would allow an even further decrease in the lattice thermal conductivity, resulting in better thermoelectric properties. IrSb{sub 3} and RuSb{sub 2}Te form a complete range of solid solutions. Hot-pressed samples in this system have shown p-type conductivity. The thermoelectric properties of these p-type alloys have been measured and results have shown that their potential for thermoelectric applications is limited mainly because of the relatively low Seebeck coefficient values for p-type materials. Efforts will be directed on preparing n-type samples of the same alloys by doping with various dopants such as Ni and Pd.
Date: July 1, 1995
Creator: Vandersande, J.W. & Caillat, T.
Partner: UNT Libraries Government Documents Department

ANNUAL TECHNICAL PROGRESS REPORT OF RADIOISOTOPE POWER SYSTEMS MATERIALS PRODUCTION AND TECHNOLOGY PROGRAM TASKS FOR OCTOBER 1, 2010 THROUGH SEPTEMBER 30, 2011

Description: The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration (NASA) for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, the Oak Ridge National Laboratory (ORNL) produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. These components were also produced for the Pluto New Horizons and Mars Science Lab missions launched in January 2006 and November 2011respectively. The ORNL has been involved in developing materials and technology and producing components for the DOE for nearly four decades. This report reflects program guidance from the Office of RPS for fiscal year (FY) 2011. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new RPS. Work has also been initiated to establish fabrication capabilities for the Light Weight Radioisotope Heater Units.
Date: May 1, 2012
Creator: King, James F.
Partner: UNT Libraries Government Documents Department

Annual Technical Progress Report of Radioisotope Power System Materials Production and Technical Program Tasks for October 1, 2005 through September 30, 2006

Description: The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2006. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new radioisotope power systems.
Date: April 2, 2007
Partner: UNT Libraries Government Documents Department

Annual Technical Progress Report of Radioisotope Power System Materials Production and Technology Program Tasks for October 1, 2004, Through September 30, 2005

Description: The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2005. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new radioisotope power systems.
Date: September 30, 2005
Partner: UNT Libraries Government Documents Department

deHAAS-vanALPEN effect in URh$sub 3$ and UIr$sub 3$

Description: Measurements of the deHaas-vanAlphen effect were performed in the intermetallic compounds URh$sub 3$ and UIr$sub 3$. Complex spectra were observed in both materials. Effective mass measurements were made for several orbits in URh$sub 3$ and values as large as 5.3 m$sub 0$ were observed. The relatively complete data in URh$sub 3$ are consistent with a complex multiply-connected Fermi surface which is in qualitative agreement with band structure calculations. The largest frequency branches in UIr$sub 3$ appear to have the same topology as their corresponding branches in URh$sub 3$. In addition, a number of closed low- mass surfaces exist in UIr$sub 3$ and are discussed in terms of the calculations for URh$sub 3$. (auth)
Date: September 1, 1975
Creator: Arko, A.J.; Brodsky, M.B.; Crabtree, G.W.; Karim, D.; Windmiller, L.R. & Ketterson, J.B.
Partner: UNT Libraries Government Documents Department

High Strain Rate Tensile Testing of DOP-26 Iridium

Description: The iridium alloy DOP-26 was developed through the Radioisotope Power Systems Program in the Office of Nuclear Energy of the Department of Energy. It is used for clad vent set cups containing radioactive fuel in radioisotope thermoelectric generator (RTG) heat sources which provide electric power for spacecraft. This report describes mechanical testing results for DOP-26. Specimens were given a vacuum recrystallization anneal of 1 hour at 1375 C and tested in tension in orientations parallel and perpendicular to the rolling direction of the sheet from which they were fabricated. The tests were performed at temperatures ranging from room temperature to 1090 C and strain rates ranging from 1 x 10{sup -3} to 50 s{sup -1}. Room temperature testing was performed in air, while testing at elevated temperatures was performed in a vacuum better than 1 x 10{sup -4} Torr. The yield stress (YS) and the ultimate tensile stress (UTS) decreased with increasing temperature and increased with increasing strain rate. Between 600 and 1090 C, the ductility showed a slight increase with increasing temperature. Within the scatter of the data, the ductility did not depend on the strain rate. The reduction in area (RA), on the other hand, decreased with increasing strain rate. The YS and UTS values did not differ significantly for the longitudinal and transverse specimens. The ductility and RA values of the transverse specimens were marginally lower than those of the longitudinal specimens.
Date: November 1, 2007
Creator: Schneibel, Joachim H; Carmichael Jr, Cecil Albert & George, Easo P
Partner: UNT Libraries Government Documents Department

Semi-Annual Technical Progress Report of the Radioisotope Power System Materials Production and Technology Program Tasks for September 2000 through March 2001

Description: The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. For the Cassini Mission, for example, ORNL was involved in the production of carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) and weld shields (WS). This report has been divided into three sections to reflect program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2001. The first section deals primarily with maintenance of the capability to produce flight quality (FQ) CBCF insulator sets, iridium alloy blanks and foil, CVS, and WS. In all three cases, production maintenance is assured by the manufacture of limited quantities of FQ components. The second section deals with several technology activities to improve the manufacturing processes, characterize materials. or to develop technologies for new radioisotope power systems. The last section is dedicated to studies related to the production of {sup 238}Pu.
Date: May 22, 2001
Creator: Moore, J.P.
Partner: UNT Libraries Government Documents Department

Low temperature properties of some Er-rich intermetallic compounds

Description: The low temperature volumetric heat capacity ({approx}3.5 to 350 K) and magnetic susceptibility ({approx}4 to 320 K) of Er{sub 3}Rh, Er{sub 3}Ir, Er{sub 3}Pt, Er{sub 2}Al, and Er{sub 2}Sn have been measured. All of the compounds order antiferromagnetically (or ferrimagnetically), and most exhibit more than one magnetic ordering transition. The volumetric heat capacities in general are smaller than those of the prototype magnetic regenerator materials, except for Er{sub 3}Ir in the 12 to 14 K temperature range.
Date: September 30, 2004
Creator: K.A. Gshneidner,jr; Pecharsky, A.O.; L.Hale & Pecharsky, V.K.
Partner: UNT Libraries Government Documents Department

Annual Technical Progress Report of Radioisotope Power System Materials Production and Technology Programs Tasks for October 1, 2005, through September 30, 2006

Description: The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2006. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new radioisotope power systems.
Date: September 30, 2006
Partner: UNT Libraries Government Documents Department

Annual Technical Progress Report of Radioisotope Power System Materials Production and Technology Tasks for October 1, 2003 through September 30, 2004

Description: The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2004. Production and production maintenance activities for flight quality (FQ) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. In all three cases, production maintenance is assured by the manufacture of limited quantities of FQ components. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new radioisotope power systems.
Date: June 1, 2005
Partner: UNT Libraries Government Documents Department

Annual Technical Progress Report of Radioisotope Power System Materials Production and Technology Tasks for October 1, 2004 through September 30, 2005

Description: The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2005. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new radioisotope power systems.
Date: August 3, 2006
Partner: UNT Libraries Government Documents Department

Bulk properties of UIr$sub 2$ and UIr$sub 3$

Description: The electrical resistivity and magnetic susceptibility of the cubic intermetallic compounds UIr$sub 2$ (MgCu$sub 2$-type) and UIr$sub 3$ (ordered, AuCu$sub 3$-type) were measured between 2-300$sup 0$K. The susceptibility of UIr$sub 3$ is temperature independent and substantially lower than that of isoelectronic URh$sub 3$, being 0.57 vs 0.97 x 10$sup -3$ emu/mole at room temperature. The susceptibility of UIr$sub 2$ is very weakly temperature dependent above 100$sup 0$K and has a value of 1.18 x 10$sup -3$ emu/mole at room temperature. The electrical resistivities of both compounds follow power law dependences at low temperatures, of the form rho-rho$sub 0$ = AT/sup n/, with n = 1.9 for UIr$sub 2$ and n = 3.7 for UIr$sub 3$. These results indicate that UIr$sub 2$ may be a spin fluctuation compound, while UIr$sub 3$ behaves as a simple transition metal compound, with even less d-f character than URh$sub 3$ (n = 3.0). The specific heat of UIr$sub 2$ was measured between 1-4K and may be fit to C =$gamma$T + $beta$T$sup 3$, with a large value of $gamma$, 62.5 mJ/(mole- K$sup 2$), which is consistent with a narrow 5f band at the Fermi level. The lack of any magnetic phenomena in UIr$sub 3$ is explained by the hybridization of the 5f electrons into f-d bands, which mostly lie below the Fermi level. (auth)
Date: December 1, 1975
Creator: Brodsky, M.B.; Trainor, R.J.; Arko, A.J. & Culbert, H.V.
Partner: UNT Libraries Government Documents Department

Energy-beam processing studies on Ta/U and Ir/Ta systems. [Laser-and electron-beam melting]

Description: Films of Ta metal on uranium and of Ir metal on tantalum have been irradiated and melted by pulses from Q-switched Ruby and frequency-doubled Nd:YAG lasers to investigate the nature of the resulting mixtures in light of the very different binary-phase diagrams of the two systems. In addition, a two-phase Ir-Ta alloy has been surface-processed with CW CO/sub 2/-laser radiation and with an electron beam in order to study microstructure refinement and test the advantage of using alloys as opposed to film-on-substrate combinations for the development of claddings.
Date: November 11, 1983
Creator: Kaufmann, E.N.; Peercy, P.S.; Jacobson, D.C.; Draper, C.W.; Huegel, F.J.; Echer, C.J. et al.
Partner: UNT Libraries Government Documents Department