DOCSLIB.ORG

Separation of Niobium and Tantalum in Liquid Extraction Ernest Lee Koerner Jr

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Separation of Niobium and Tantalum in Liquid Extraction Ernest Lee Koerner Jr Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1956 Separation of niobium and tantalum in liquid extraction Ernest Lee Koerner Jr. Iowa State College Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Chemical Engineering Commons Recommended Citation Koerner, Ernest Lee Jr., "Separation of niobium and tantalum in liquid extraction " (1956). Retrospective Theses and Dissertations. 13320. https://lib.dr.iastate.edu/rtd/13320 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps. ProQuest Information and Learning 300 North Zeeb Road. Ann Arbor, Ml 48106-1346 USA 800-521-0600 NOTE TO USERS This reproduction is tlie best copy available. UMI* UNCLASSMED Title: Separation of Niobium and Tantalum by Liquid Extraction Author; Ernest Lee Koerner, Jr» (official certification of the classification shown is filed in the Ames Laboratory Document Library) Signature was redacted for privacy. Secretary to Declassification Committee UNCLASSlflEL SEPARATION OF NIOBIUM AND TAUTAIITM BY XigJID EXTRACTION Ernest lee Ebemer, Jr A BlsBertatlon Submitted to the Graduate Faculty in Partial Fulfillment of The Se(|uireinenta for the Degree of DOCTOR OF PHILOSOPHT Major. fi«niJjatst: M'.t}&e]Bieal.Engineering • •• •• • Approved: Signature was redacted for privacy. Signature was redacted for privacy. lartment Signature was redacted for privacy. Dean of toaduat'e College lova State College 1956 UMI Number: DP12438 ® UMI UMI Microform DP12438 Copyright 2005 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 Tr^-fS./v'? !EABLB OF COHUBNOIS Pagt SOMMAHT 1 JNTHODUCTION 3 PBEVIOUS WOBK 2 IHVESTIGATIOII 19 Opening of the Ore 19 Preparation of the Extractor Feed Solution 29 Separation of Niobium and Tantalum 3^ Solvent Treatment and Recovery 69 final Conversion of Products JZ COST MAL7SIS 7^ Chemical Costs 77 Equipment Costs and Investment 77 Operating Costs 79 DlSCUSSIOir OF EBStJIiTS 85 LITERATUHE CITEa) 92 ACKROWLEaJOMEJHTS 95 APPENDICES 96 APESHDIX A 97 Analytical Methods 97 jffPEHDIX 100 T/Zi^O iU LIST OF fABLQS Page Talkie 1. Kio'bltutt-baaring mlDarals 9 Table 2. Looatlon and eetioated reserves of nlo'bltua d^oalts 10 Table 3> Ledotuc analysis of Nigerian eoltmblte ore 20 Table U. Seventy per cent hydrofluoric aold regulrementa of Nigerian coltunblte ore 22 Table 5* ^0 effect of diethyl ketone on the hydrofltiorlo aold-ooltunblte ore reaction 23 Table 6. Effect of sulfuric acid on the hydrofluoric acid treatswnt of colunblte ore 2^ Table J. BeaetiAb of Nigerian colunblte ore vlth anhydrous hydrofluoric aold 26 Table 8. Beactlons of fO per cent hydrofluoric aold and columblte ore at 100^ 0...... 28 Table 9. Sq[alllbrlun contacts with varying oxide concentration In diethyl ketone and one molar eulfarlo acid Uo Table 10. Stagevlse analyses for the first nloblun- tantalum slinulated column run using diethyl ketone Table 11. Stagevlse analyses for the second nloblun- tantalum simulated column run uAlng diethyl ketone ^7 Table 12. Stagevlse analyses for the fifth niobium- tantalum simulated column run using diethyl ketone ^9 Table 13. Stagevlse excess hydrofluoric acid determination for the eq|ulllbrlum phases of the fifth simulated column run using diethyl ketone 5^ IT Table lU. Sta^wlse analyse* for the second niobium- tantalum sinulated eoluan run using bsxon* ^6 Table l^. Stagevise analyses for the third niobiua- tantalum siimilated column run using hexone 60 Ta'ble l6. Stagswise analyses for the fourth niobium- tantalum simulated column run using hexone 63 Table I7. Stagewise analyses for niobium-tantalum continuous extraction run 68 Table 18. Preliminary rav material cost estimate for the proposed niobium and tantalum purification process . 7^ Table I9. Installed process eo(aipinent cost for the proposed niobium and tantalum purification plant 80 Table 20. Capital inrestment for the proposed niobium and tantalum purification plant 82 Table 21. Preliminaiy process cost estimate for niohium- tantalum purification plant 83 Tahle 22. Sq|uilibrium data for pure niobium and tantalum fltioridss with hexons 100 T LIST OF 7IGUBSS FlgoM 1. Proposed process for the separation of niobium and tantalum 6 Figure 2. distribution curves for pure niobium and tantalum fluorides with hexone 3^ Figure 3* Effect of initial feed concentration in diethgrl ketone on tajitalua-niobiua separation factors ... 39 Figure U. Equilibrium diagram for the fifth diethyl ketone simulated column ^1 Figure Sq[ulllbrlum diagram for the second hexone simulated column run I . , 33 Figure 6. Sqjuilibrium diagram for the third hexone simulated column run 3S Figure 7. Eqiuilibrium diagram for the fourth hexone simulated column run 63 Figure g. Photograph of the polyethylene mixer-settler extractor 66 Figure 9* Qpantitatiye flov diagram for the proposed process 76 1 SUMHAWr irio1)lttm, also knowx as eoluiniblum. Is one of the new Indiuitrial metals likely to play an is^ortant role in industrial processing In the near future. Its high melting point (U376^ S*.) and low cross section for neutron alisozption (l.l barne) makes it of special interest to the Atomic Snergy Commission. Since tantalum, which invariably acconqpanies niobium in its ores, has a somewhat hi^er cross section for neutron absorption (21 bams) there is considerable interest in developing an industrial process for producing tantalum^free niobium. Tantalum itself is a valuable metal because of its hi^ melting point ) and its resistance to most corrosive chemicals. !I!he purpose of this research was to find an economical method of producing a niobium oxide product containing ais little tantalum and other impurities as possible starting with a typical niobiumorich ore or concen­ trate. The process selected as a result of the research consisted of the following processing steps: 1. Digestion of the ore or concentrate with hydrofluoric acid. 2. Sxtractibn of niobium and tantalum from the digested mass with an organic solvent suoth as methyl isobutyl ketone. 3. Separation of tantalum and niobium by continuous countercxirrent multistage extraction using an organic solvent and an aqueous scrubbing solvent. 2 Separation of nloljiam from other ixi^tiritles "by a second solvent extraction step using an organic solvent. Stripping of the niohitun and tantaltui from their solvents and regeneration of solvents. IThe process as outlined above was studied on a small scale and demonstrated on a somewhat larger scale so that a more accurate cost estimate could he made. Several pounds of nlohium oxide containing less than 700 parts per million of tantalum oxide tKere produced. Several pounds of tantalum oxide containing less than 100 parts per million of niobium oxide mre produced. Both purity values v^ere the limit of detection for the i^ectrogre{)hio methods en^loyed. Preliminary cost estimates veve made for production of purified niohiun and tantalum oxides from an ore concentrate assaying 63 paz* cent niohium oxide and 7 cent tantalum oxide. The basis chosen was a plant producing 300,000 pounds of total oxides per year or 270,000 pounds niohium oxide and 30,000 pounds tantalum oxide. Estimated chemical and total operating costs for oxie poxuid of either tantalum or niohium oxide vere ^1.89 and 3 imOBUOTlOH moblvfii and tantaliua have had an Interesting histoxy. In 1801 Hatehett discovered niohitm in a Connecticut mineral. Since niohium-i hearing minerals without tantalum are virtually unknown, the first investi­ gators irfere dealing with mixtures of these tvo chemically similar elements* IThe presence of titanium in some cases caused additional con^lications. Before their final identification, seven names had heen ascribed to new elements that were thoTight to he present in these minerals. Marignac finally identified the two elements in 1866 hy separating them as complex potassiuB fluorides hy fractional crystallization. He found that the con^lex niobium fluoride was isomoxphous with the known salts EgTlFg* 1^0 and vAiich indicated that the valence of niohium was and the formula of
Load more

Recommended publications
  • Electrical and Dielectrical Properties of Tantalum Oxide Films Grown
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by DSpace@IZTECH Institutional Repository Thin Solid Films 517 (2008) 994–999 Contents lists available at ScienceDirect Thin Solid Films journal homepage: www.elsevier.com/locate/tsf Electrical and dielectrical properties of tantalum oxide films grown by Nd:YAG laser assisted oxidation G. Aygun a,⁎, R. Turan b a Department of Physics, İzmir Institute of Technology, Gulbahce Campus, TR-35430, Urla-İzmir, Turkey b Department of Physics, Middle East Technical University, TR-06531, Ankara, Turkey article info abstract Article history: Tantalum pentoxide (Ta2O5) thin films (20 to 44 nm) have been grown by 1064 nm Nd:YAG laser oxidation of Received 23 March 2007 Ta deposited films with various thickness on Si. Fourier Transform Infrared (FTIR) spectrum, thickness Received in revised form 23 July 2008 distribution, dielectric and electrical properties of laser grown oxide layers have been studied. The effect of Accepted 30 July 2008 the sputtered Ta film thickness, laser beam energy density and the substrate temperature on the final Ta O Available online 3 August 2008 2 5 film structure has been determined. It is shown that the oxide layers obtained for the laser beam energy density in the range from 3.26 to 3.31 J/cm2 and the substrate temperature around 350 °C have superior Keywords: Dielectric properties properties. FTIR measurement demonstrates that the Ta2O5 layers are obtained with the laser assisted Electrical properties oxidation technique. Metal Oxide Semiconductor capacitors fabricated on the grown oxide layers exhibits Insulators typical Capacitance–Voltage, Conductance–Voltage and Current–Voltage characteristics.
    [Show full text]
  • United States Patent (19) 11 3,929,495 Broemer Et Al
    United States Patent (19) 11 3,929,495 Broemer et al. (45) Dec. 30, 1975 54) OPTICAL BORATE GLASS OF HIGH 3,149,984 9/1964 Faulstich........................... 106/47 R CHEMICAL RESISTANCE AND PROCESS 3,307,929 3/1967 Trap.................................. 106/47 R 3,480,453 it 1/1969 Reid et al.......................... 106/47 R OF MAKING SAME 3,486,915 12/1969 Broemer et al................... 106/47 R (75) Inventors: Heinz Broemer, Hermannstein; 3,510,325 5/1970 Broemer et al................... 106/47 R Norbert Meinert, Wetzlar, both of FOREIGN PATENTS OR APPLICATIONS Germany 863,352 3/1961 United Kingdom............... 106/47 Q 73 Assignee: Ernst Leitz G.m.b.H., Wetzlar, 4,424,420 10/1969 Japan................................ 106/47 Q Germany Filed: May 15, 1973 Primary Examiner-Winston A. Douglas 22) Assistant Examiner-Mark Bell 21 Appl. No.: 360,418 Attorney, Agent, or Firm-Erich M. H. Radde 30 Foreign Application Priority Data 57 ABSTRACT May 15, 1972 Germany............................ 2223564 An optical borate glass of high chemical resistance, with negative anomalous partial dispersion, refraction 52) U.S. Cl. ............................. 106/47 Q; 106/47 R index n between 1,65 and 1,79, and Abbe number ve 51 Int. CI..... C03C 3/14: CO3C 3/00; C03C 3/30 between 40 and 30 is composed of boron trioxide, 58) Field of Search......................... 106/47 O, 47 R lead oxide, and aluminum oxide. It may additionally contain lithium, sodium, and/or potassium oxides, zinc (56) References Cited oxide, zirconium dioxide, tantalum pentoxide, and, if UNITED STATES PATENTS desired, antimony trioxide and/or bismuthum trioxide.
    [Show full text]
  • SYNTHESIS, CHARACTERIZATION, and PHOTOCATALYTIC ACTIVITY of TANTALUM OXIDE THIN FILMS by CODY JENSEN THESIS Submitted in Partial
    SYNTHESIS, CHARACTERIZATION, AND PHOTOCATALYTIC ACTIVITY OF TANTALUM OXIDE THIN FILMS BY CODY JENSEN THESIS Submitted in partial fulfillment of the requirements for the degree of Master of Science in Chemical Engineering in the Graduate College of the University of Illinois at Urbana-Champaign, 2011 Urbana, Illinois Advisers: Professor Mark Shannon Professor David Cahill ABSTRACT An increasing demand for a low cost alternative for water disinfection and the recent push for green energy has caused an explosion of research in photocatalysis. While TiO2 is considered to be the standard for photocatalysis, there are a number of issues that need to be overcome to push photocatalysis into mainstream applications. In an effort to improve the overall reaction rate, a wider energy gap material, such as Ta2O5, that provides a higher cathodic potential and more flexibility in shifting the energy gap provides a possible alternative. Ta2O5 thin films were synthesized using a sol-gel method and deposited by dip-coating and spin- coating. The thicknesses of the films ranged from 8 nm to 230 nm and were tested to find an optimum thickness based on the quantum efficiency. The photoactivity of the films was measured using a recirculating methylene blue solution. Above 15 nm, the film thickness did not have an effect on the methylene blue degradation rate. To test the premise of being limited by electron-hole transport, the annealing temperature of the films was varied to increase the crystallinity. The films were annealed under a range of temperatures from 450°C to 1200°C. By x-ray diffraction measurements, the grain size of the films was found to be relatively stable from 638°C to 1075°C.
    [Show full text]
  • Electrical Properties of Ta2o5 Films Deposited on Zno
    Bull. Mater. Sci., Vol. 26, No. 4, June 2003, pp. 365–369. © Indian Academy of Sciences. Electrical properties of Ta2O5 films deposited on ZnO S K NANDI*, S CHATTERJEE, S K SAMANTA, G K DALAPATI, P K BOSE†, S VARMA‡, SHIVPRASAD PATIL‡ and C K MAITI Department of Electronics and ECE, Indian Institute of Technology, Kharagpur 721 302, India †Department of Mechanical Engineering, Jadavpur University, Kolkata 700 032, India ‡Institute of Physics, Bhubaneswar 751 005, India MS received 25 March 2003 Abstract. High dielectric constant (high-k) Ta2O5 films have been deposited on ZnO/p-Si substrate by micro- wave plasma at 150°C. Structure and composition of the ZnO/p-Si films have been investigated by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) for chemical composition. The electrical properties of the Ta2O5/ZnO/p-Si metal insulator semiconductor (MIS) structures were studied using high frequency capacitance–voltage (C–V), conductance–voltage (G–V) and current–voltage (I–V) characteristics. Charged trapping properties have been studied by measuring the gate voltage shift due to trapped charge generation under Fowler– Nordheim (F–N) constant current stressing. Keywords. ZnO; Ta2O5; rf magnetron sputtering; microwave plasma; PECVD; high-k. 1. Introduction stant, thermal stability and adequate breakdown voltage (Cappellani et al 1999; Nandi et al 2002). Zinc oxide (ZnO) is of great interest as a suitable mate- In this paper, we report the plasma enhanced chemical rial for high temperature, high power electronic devices vapour deposition (PECVD) of Ta2O5 layers on rf-sputtered either as the active material or as a suitable substrate for undoped ZnO films.
    [Show full text]
  • United States Patent (19) 11 Patent Number: 5,635,146 Singh Et Al
    US005635146A United States Patent (19) 11 Patent Number: 5,635,146 Singh et al. 45 Date of Patent: Jun. 3, 1997 54 METHOD FOR THE DISSOLUTION AND Tantalum, Elements, 12-17 (1992) (no month available). PURIFICATION OFTANTALUMPENTOXDE Abstract, Derwent WPI, JP 043298808A, (1992) (no month 75 Inventors: Raj P. Singh, Sayre; Michael J. available). Miller, Towanda, both of Pa. Bielecki, Use of Ion Exchange Techniques for Production of High-purity Potassium Fluorotantalate, Advances in 73) Assignee: Osram Sylvania Inc., Danvers, Mass. Extractive Metallurgy, The Institute of Mining and Metal lurgy, London, 777-788 (Apr. 17-20, 1967). 21 Appl. No.: 565,334 Carlson et al., Pure Columbium and Tantalum Oxides by Liquid-Liquid Extraction, Journal of Metals, 472-475 (Jun. 22 Filed: Nov.30, 1995 1960). (51 int. Cl. ... C01G 3500 Droeghkamp et al., Tantalum and Tantalum Compounds, 52 U.S. C. ...... ... 423/65; 423/67; 423/68; Kirk-Othmer Encyclopedia of Chemical Technology, Third 423/592; 423/593 Ed., v.22, 541-565, John Wiley & Sons (1983) no month 58 Field of Search ............................ 423/65, 67, 68, available. 423/592,593 Baram, Kinetics of Dissolution of Niobium and Tantalun Pentoxides in Hydrofluoric Acid, Journal of Applied Chem 56) References Cited istry of the USSR, 38, 2181-2188 (1965) (no month avail U.S. PATENT DOCUMENTS able). 3,072,459 1/1963 Foos et al. 423/67 Zelikman et al., Chapter III: Tantalum and Niobium, Met 3,117,833 1/1964 Pierret ......................................... 23/19 allurgy of Rare Metals, U.S. Dept. of Commerce, 99-154 3,481,694 12/1969 Hudswell et al.
    [Show full text]
  • Eparating the Columbium and Tantalum Salts Or Oxides from Each Other
    TANTALUM, COLUMBIUM, AND FERROCOLUMBIUM A. Commodity Summary Tantalum is used in the electronics industry, as well as in aerospace and transportation applications. Columbium (the commonly used synonym for the element niobium) is used as an alloying element in steels and in superalloys. Tantalum and columbium are often found together in pyrochlore and baripyrochlore, the main columbium containing minerals, as well as in columbite. These minerals contain relatively small amounts of tantalum, pyrochlore, and baripyrochlore, having a columbium pentoxide-to-tantalum pentoxide ratio of 200 to 1 or greater.1 Columbite contains slightly larger amounts (up to eight percent) of tantalum.2 Tantalite is the primary source of tantalum pentoxide, and contains small amounts of columbium pentoxide. Microlite is another source of tantalum pentoxide. Tantalum is also recovered from tin slags.3 There has been no significant mining of tantalum or columbium ores in the United States since 1959. Producers of columbium metal and ferrocolumbium use imported concentrates, columbium pentoxide, and ferrocolumbium. Tantalum products are made from imported concentrates and metal, and foreign/domestic scrap.4 Ferrocolumbium is an alloy of iron and columbium. Ferrocolumbium is used principally as an additive to improve the strength and corrosion resistance of steel used in high strength linepipe, structural members, lightweight components in cars and trucks, and exhaust manifolds. High purity ferrocolumbium is used in superalloys for applications such as jet engine components, rocket assemblies, and heat-resisting and combustion equipment.5 Exhibit 1 summarizes the principal producers of tantalum, columbium and ferrocolumbium in the United States in 1992. Only Cabot Corporation and Shieldalloy Metallurgical Corporation use ores as their starting material.6 B.
    [Show full text]
  • Columbium & Tantalum
    GM 02667 COLUMBIUM & TANTALUM QUEBEC (PROV.OF). QUEBEC DEPARTMENT OF MINES 1954 MINERAL DEPOSITS BRANCH COLUMBIUM TANTALUM Compilation by; P.E.Pelletier. i24 -47 ,: ^ fov,- COLUMBIUM AND TiNTALUM OCCURRENCE. The columbium and tantalum minerals-are, frequently found associated with granitic rocks, like the coarse pegmatites. The following minerals and mineral series provoke considerable interest its Canada. pvrochlore-Mtcroli e . •• Three of 18 analyses show a II 0gg content of over 181; these high uranium varieties hay* been called ellsworthite, and hatchettolite. In the remainder uranium and thorium are low or absent. The columbium-tantalum oxide content has a minimum of 35% but may reach 80%, „Fe r¢usonigor ate - in. all of 11 analyses both uranium . and_.thorium are low. The columbium-tantalum oxide content ranges between 40--55%. nite-Poly - only two of 13 analyses show a ïI 03 content of over 1 . Thorium is always less than 10%, The columbium-tantalum oxide content is usually between 20-30% but may reach 50%. l of 11 the g content Is less1 Five of the analysesn show thorium oxid as more than 10%. The columbium-tantalum oxide content varies between 16.55%• S s ;•_ - five of nine analeses show U308 over. l• . Thorium is always less than 10%. The columbium-tantalum oxide content varies between 43-60%, Betafite - the O8 content in eight analyses varies between 10-27%. Thoriui is always less than 1.5%. The. columbium-tantalum oxide content varies between 18-51%. These minerals have several features in common. They are all multiple oxides of columbium and tantalum; uranium, thorium and the rare earth elements are usually present.
    [Show full text]
  • Dielectric Relaxation of High-K Oxides Chun Zhao1, Ce Zhou Zhao1,2*, Matthew Werner3,4, Steve Taylor1 and Paul Chalker3
    Zhao et al. Nanoscale Research Letters 2013, 8:456 http://www.nanoscalereslett.com/content/8/1/456 NANO REVIEW Open Access Dielectric relaxation of high-k oxides Chun Zhao1, Ce Zhou Zhao1,2*, Matthew Werner3,4, Steve Taylor1 and Paul Chalker3 Abstract Frequency dispersion of high-k dielectrics was observed and classified into two parts: extrinsic cause and intrinsic cause. Frequency dependence of dielectric constant (dielectric relaxation), that is the intrinsic frequency dispersion, could not be characterized before considering the effects of extrinsic frequency dispersion. Several mathematical models were discussed to describe the dielectric relaxation of high-k dielectrics. For the physical mechanism, dielec- tric relaxation was found to be related to the degree of polarization, which depended on the structure of the high- k material. It was attributed to the enhancement of the correlations among polar nanodomain. The effect of grain size for the high-k materials' structure mainly originated from higher surface stress in smaller grain due to its higher concentration of grain boundary. Keywords: Frequency dispersion; High-k; Grain size; Dielectric relaxation Review [40,41], lanthanum-doped zirconium oxide LaxZr1−xO2−δ Background [42,43], hafnium oxide HfO2 [44], HfO2-based oxides As the thickness of SiO2 gate dielectric films used in La2Hf2O7 [45], CexHf1-xO2 [46], hafnium silicate HfSixOy complementary metal oxide semiconductor (CMOS) de- [47], and rare-earth scandates LaScO3 [48], GdScO3 vices is reduced toward 1 nm, the gate leakage current [49], DyScO3 [50], and SmScO3 [51]. Among them, level becomes unacceptable [1-4]. Extensive efforts have HfO2, HfO2-based materials, ZrO2, and ZrO2-based ma- been focused on finding alternative gate dielectrics for terials are considered as the most promising candidates future technologies to overcome leakage problems [5-7].
    [Show full text]
  • Crystallization Improvement of Ta2o5 Thin Films by the Addition of Water
    ARTICLE IN PRESS Journal of Crystal Growth 274 (2005) 73–77 www.elsevier.com/locate/jcrysgro Crystallization improvement of Ta2O5 thin films by the addition of water vapor A.P. Huang, Paul K. Chuà Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Received 16 September 2004; accepted 5 October 2004 Communicated by R. Kern Available online 13 November 2004 Abstract We report that by the addition of water vapor into the working gas, crystalline tantalum pentoxide (Ta2O5) thin films can be fabricated at low substrate temperatures. At 500 1C, by the addition of water vapor, the crystallinity of the thin films was obviously improved. The grains with tetragonal structure were clearly observed by AFM. Total transmission greater than 85% was achieved between wavelengths of 400 and 800 nm and the optical absorption edge of the thin films also shifted to smaller wavelength. Our data suggest that the crystallinity of the thin films can be improved and the crystallized temperature can be decreased with the introduction of water vapor in the fabrication process. The effects of water vapor on the crystallization of Ta2O5 thin films are discussed in details. r 2004 Elsevier B.V. All rights reserved. PACS: 68.55.Ac; 61.50.Àf Keywords: A1. Crystal structure; B1. Oxides; B2. Dielectric materials 1. Introduction reached its limits due to the high direct tunneling current. As one of the alternative gate dielectric As the feature size of ultra large-scale integra- materials, tantalum pentoxide (Ta2O5) has been tion (ULSI) devices shrinks, thinner gate oxides studied extensively in applications such as storage are necessary to achieve high performance in metal capacitors in dynamic random access memory oxide silicon field effect transistors (MOSFET).
    [Show full text]
  • Fabrication and Performance of Zno Doped Tantalum Oxide Multilayer Composite Coatings on Ti6al4v for Orthopedic Application
    nanomaterials Article Fabrication and Performance of ZnO Doped Tantalum Oxide Multilayer Composite Coatings on Ti6Al4V for Orthopedic Application Ziyu Ding 1, Quanguo He 1,2,*, Zeliang Ding 3,*, Cuijiao Liao 3, Dongchu Chen 2 and Ling Ou 4 1 School of Life Sciences and Chemistry, Hunan University of Technology, Zhuzhou 412007, China; [email protected] 2 School of Materials Science and Energy Engineering, Foshan University, Foshan 528000, China; [email protected] 3 School of Mechanical Engineering, Hunan University of Technology, Zhuzhou 412007, China; [email protected] 4 Jiangsu Key Laboratory of Materials Surface Science and Technology, Changzhou University, Changzhou 213164, China; [email protected] * Correspondence: [email protected] (Q.H.); [email protected] (Z.D.) Received: 28 February 2019; Accepted: 30 April 2019; Published: 2 May 2019 Abstract: Ti6Al4V titanium alloy has been widely used as medical implant material in orthopedic surgery, and one of the obstacles preventing it from wide use is toxic metal ions release and bacterial implant infection. In this paper, in order to improve corrosion resistance and antibacterial performance of Ti6Al4V titanium alloy, ZnO doped tantalum oxide (TaxOy) multilayer composite coating ZnO-TaxOy/TaxOy/TaxOy-TiO2/TiO2/Ti (ZnO-TaxOy) was deposited by magnetron sputtering at room temperature. As a comparison, monolayer TaxOy coating was prepared on the surface of Ti6Al4V alloy. The morphology and phase composition of the coatings were investigated by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD), the elemental chemical states of coating surfaces were investigated by X-ray photoelectron spectroscope (XPS). The adhesion strength and corrosion resistance of the coatings were examined by micro-scratch tester and electrochemical workstations, respectively.
    [Show full text]
  • Synthesis and Characterization of Tantalum Oxide-Based Nanowire
    SYNTHESIS AND CHARACTERIZATION OF TANTALUM OXIDE-BASED NANOWIRE HETEROSTRUCTURES FOR PHOTOCATALYSIS by LYNDON E. SMITH JR. DR. NITIN CHOPRA, COMMITTEE CHAIR DR. RAMANA G. REDDY DR. C. HEATH TURNER A THESIS Submitted in partial fulfillment of the requirements for the degree of Master of Science in the Department of Metallurgical and Materials Engineering in the Graduate School of The University of Alabama TUSCALOOSA, ALABAMA 2012 Copyright Lyndon E. Smith Jr. 2012 ALL RIGHTS RESERVED ABSTRACT Semiconductor nanostructures under irradiation catalyze the mineralization of organic dyes in solution. To improve the efficiency of this process, many novel nano-heterostructures have been fabricated using a variety of synthetic methods, however, many of these methods require management of difficult to control parameters, days of aging, and dangerous or expensive precursors to synthesize nanomaterials that may lack uniformity, recoverability, or efficiency. In this thesis, 1D CuO-TaOx-NiOy nano-heterostructures are fabricated using a combination of thermal oxidation and DC magnetron sputter deposition. CuO nanowires were synthesized by thermal oxidation, and TaOx and NiOy were deposited onto CuO nanowire template by sputter deposition of the metal followed by thermal annealing in air. A systematic study was done on the effect of sputter deposition parameters and annealing temperature for Ta. The completed heterostructure was evaluated by its performance in the degradation of various organic dyes. CuO-TaOx-NiOy nanowires with thin (10 nm thick) layers in methylene blue (concentration = 20 mg/L) with a catalyst dose of 1.0 g/L were found to be the most efficient catalyst. Rationally engineered semiconductor nano-heterostructures can be applied in environmental remediation and reduce the amount of pollution from industrial waste effluent.
    [Show full text]
  • 22%2-2-24 Attorneys 3,011,866 United States Patent Office Patented Dec
    Dec. 5, 1961 J. O. GEBSON 3,011,866 SEPARATION OF COLUMBIUM AND TANTALUM Filed Jan. 10, 1958 -2OO MESH ORE CARBON HEAT 5OOOC WOATE Cb Cls l To Cls OTHER CHLORDES DISTILLATION 2 WOLATLE COLUMBUM NON- VOLATLE TANTALUM SOLUBLE IMPURITIES H2O INSOLUBLE Ta2Ox HO 5 SOLUBLE IMPURTIES ORE CONCENTRATE IS CARBONS H2O HO SOLUBLE IMPURITIES-le-FILTER FILTER-e-SOLUBLE EMPURITIES Toa x HO c. x HO sTE GNITE To2O co, E if g . - 2 INVENTOR. Jannes O. Gibson 22%2-2-24 ATTORNEYs 3,011,866 United States Patent Office Patented Dec. 5, 1961. 2 3,0866 FIG. 1 is a schematic flow sheet illustrating process SEPARATION OF Coifyisit M AND TANTALUM of the invention for separating columbium and tantalum ames C. Gibson, Littletoa, Coio. from a concentrate of their ores, and (58 Whitman Drive, New Providence, N.J.) FIG. 2 is a cross sectional view of a simplified batch Filed Jaa.. i0, 1958, Ser. No. 708,307 process for carrying out the method of the invention, and 7 Clairas. (C. 23-17) includes a simplified flow sheet of the method for re covering and separating columbium and tantalun. This invention relates to a commercial process for the separation of columbian, otherwise known as niobium, Example I and tantalun froin ores containing the elements. O In carrying out the process of the invention an ore Columbium, or niobium, is almost always found asso concentrate containing columbium and taintalum ground ciated with tantalun in ores, and in the United States and to about 200 mesh is mixed with carbon.
    [Show full text]