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Niobium Phase Diagrams : Manuscript Report on Niobium-Oxygen System

Description: Abstract: "The niobium-oxygen equilibrium has been determined by metallographic examination of arc-cast alloys made of electron-gun-refined niobium metal and special purity niobium pentoxide. Two intermediate oxides, NbO and NbO2, melt without decomposition at 1945 C and 1915 C, respectively. Eutectic reactions exist between niobium and NbO and 1915 C and between NbO and NbO2 at 1810 C. Experimental supports a peritectic reaction between NbO2 and Nb2O5 1510 C. The maximum solid solubility of oxygen in niobium metal is 0.72 weight per cent."
Date: April 27, 1959
Creator: Elliott, Rodney P.
Partner: UNT Libraries Government Documents Department

Niobium Phase Diagrams : Manuscript Report on Niobium-Carbon System

Description: Abstract: "The niobium-carbon system has been determined by X-ray and metallographic examination of sintered and arc-cast alloys. Two carbides exist: hexagonal Nb2C with a limited range of homogeneity, and cubic NbC with a solubility range from 8.25 to 10.25 weight per cent carbon. Dilute alloys freeze by eutectic reaction at 2230 C. The solubility of carbon in niobium is 0.80 at the eutectic temperature, but this decreases rapidly with temperature. Metallographic evidence indicates a peritectic reaction between melt, Nb2C, and NbC; alloys richer in carbon than NbC freeze by eutectic reaction."
Date: May 6, 1959
Creator: Elliott, Rodney P.
Partner: UNT Libraries Government Documents Department

Niobium Phase Diagrams

Description: The following report is the final technical report on a series of reports under contract AT(11-1)-515, titled "Niobium Phase Diagrams", covering the period from April 15, 1957 to April 16, 1960.
Date: May 15, 1960
Creator: Elliott, Rodney P. & Komjathy, Steven
Partner: UNT Libraries Government Documents Department

Chemical Research Section Progress Report for January 1950

Description: The following documents are progress reports that follow chemical research studies in subjects such as ruthenium tetroxile distillations, extraction-scrub studies of zirconium and niobium, and oxidation of plutonium and stabilization of plutonium(VI) during extraction of IAF solutions.
Date: February 15, 1950
Creator: Albaugh, F. W.
Partner: UNT Libraries Government Documents Department

Exploratory Scavenging Studies for the Decontamination of Redox Solutions

Description: From introduction: "This report is concerned with exploratory experiments designed to studies the efficiency of a number of scavengers for zirconium and niobium adsorption and to provide preliminary information on the best conditions to employ on the most satisfactory of those scavengers studied, namely Super Filtrol FO. The data in this report include data obtained through October, 1949, and are by no means considered to be final. The investigation is currently being actively continued."
Date: May 1, 1950
Creator: Roake, W. E. & Lowe, C. S.
Partner: UNT Libraries Government Documents Department

Transient-Liquid-Phase and Liquid-Film-Assisted Joining ofCeramics

Description: Two joining methods, transient-liquid-phase (TLP) joining and liquid-film-assisted joining (LFAJ), have been used to bond alumina ceramics. Both methods rely on multilayer metallic interlayers designed to form thin liquid films at reduced temperatures. The liquid films either disappear by interdiffusion (TLP) or promote ceramic/metal interface formation and concurrent dewetting of the liquid film (LFAJ). Progress on extending the TLP method to lower temperatures by combining low-melting-point (<450 C) liquids and commercial reactive-metal brazes is described. Recent LFAJ work on joining alumina to niobium using copper films is presented.
Date: February 9, 2005
Creator: Sugar, Joshua D.; McKeown, Joseph T.; Akashi, Takaya; Hong, SungM.; Nakashima, Kunihiko & Glaeser, Andreas M.
Partner: UNT Libraries Government Documents Department

THE SELF-DIFFUSION OF NIOBIUM--I. First Annual Progress Report, January 1, 1956 to June 30, 1957

Description: The measurement of the self-diffusion coefficient of niobium as a function of temperature has been undertaken. It is planned to prepare the diffusion couples by the deposition of Nb/sup 95/ onto the surfaces of niobium discs from the Nb/sup 95/Cl/sub 5/ vapor phase and to anneal the couples in the temperature range 1600 deg to 2000 deg K. Details are given of the construction of the vapor deposition apparatus and of the preparation of Nb/sup 95/Cl/sub 5/ from the oxalate form in which the isotope is received. Preliminary measurements of the diffusion coefficient in a Nb-8 wt.% Ti alloy and In a Nb-1.4 wt.% V alloy indicate that the diffusion coefficient in the former is approximately 10/sup -9/ cm/sup 2//sec at 1600 deg C and is approximately 8 x 10/sup -11/ cm/sup 2//sec in the latter at 1400 deg C. (auth)
Date: February 1, 1958
Creator: Resnick, R.; Castleman, L.S. & Seigle, L.
Partner: UNT Libraries Government Documents Department

Half-Wave, beta=0.43 Cavity Prototyping for a Heavy Ion Linac

Description: A medium velocity half wave resonator has been designed and prototyped at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) for use in a heavy ion linac. The cavity is designed to provide 3.7 MV of accelerating voltage at an optimum beta = v/c = 0.53, with peak surface electric and magnetic fields of 32.5 MV/m and 79 mT, respectively. The cavity was designed for stiffness and tunability, as well as straightforward fabrication, assembly and cleaning. Measurements were performed to confirm Finite Element Analysis (FEA) predictions for modal analysis, bath pressure sensitivity, tuner stiffness and tuning range. A copper cavity prototype has been fabricated to confirm tolerances and formability. A tuner prototype has been built. The helium vessel and power coupler have been designed.
Date: April 1, 2008
Creator: Popielarski, John; Compton, Chris C.; Hartung, Walter; Johnson, Mat; Oliva, John; York, R. C. et al.
Partner: UNT Libraries Government Documents Department

Research and development for electropolishing of Nb for ILC accelerator cavities

Description: The objectives of this project are to 1, Expand the scientific and technological understanding of the effect of post-treatment (electropolish, buffered chemical polish, low-temperature baking) on the surface of niobium; 2, Relate the knowledge to the performance of niobium superconducting radiofrequency accelerator cavities; and, 3, Thereby design and demonstrate an electropolish process that can be applied to complete cavities.
Date: September 21, 2009
Creator: Kelley, Michael J.
Partner: UNT Libraries Government Documents Department