Refractory Metals Abstract

  • Effects of Impurities in Some Refractory Metal-Alkali ...

    Abstract. Impurities such as oxygen, nitrogen or carbon in either the refractory metal or the alkali metal can have a significant effect on compatibility in refractory metal-alkali metal systems.

  • OSA | Broadband perfect absorber based on one ultrathin ...

    Broadband perfect absorber based on one ultrathin layer of the refractory metal chromium without structure patterning is proposed and demonstrated. The ideal permittivity of the metal layer for achieving broadband perfect absorption is derived based on the impedance transformation method. Since the permittivity of the refractory metal chromium matches this ideal permittivity well in the ...

  • International Journal of Refractory Metals and Hard ...

    The International Journal of Refractory Metals and Hard Materials (IJRMHM) publishes original research articles concerned with all aspects of refractory metals and hard materials. Refractory metals are defined as metals with melting points higher than 1800 °C.

  • Coherent Coatings of Refractory Metal | Science

    A general process has been developed for the electrodeposition of eight of the nine refractory metals of groups IVB, VB, and VIB as dense coherent deposits. It consists essentially of the electrolysis of a solution of the refractory metal fluoride in a molten alkali-fluoride euteotic mixture, and has been shown to deposit a coating, unalloyed with the substrate, by a pro- cess that obeys ...

  • Shock reactive synthesis of refractory metal aluminides ...

    TY - CHAP. T1 - Shock reactive synthesis of refractory metal aluminides and silicides. AU - Aizawa, Tatsuhiko. PY - 1997. Y1 - 1997. N2 - Shock induced reactions in the Ni-Al and Mo-Si systems are experimentally investigated with consideration of the pretreatment effect on the shock reactivity.

  • Welding, Brazing and Joining of Refractory Metals and ...

    Mar 26, 2008· Abstract Refractory metals and their alloys can be joined by gas tungsten are. electron beam, and resistance welding. Also, they can be joined by brazing and solid state bonding. In the case of brazing or solid state bonding, dissimilar metal joining is possible. The essential parameters to be carefully controlled are interstitial contents, the processing temperature relative to ...

  • US4662998A - Electrodeposition of refractory metal ...

    A refractory metal silicide coating is electrodeposited onto an object, using a bath containing an alkali fluoride melt, a silicon fluoride dissolved in the melt, a refractory metal-containing compound also dissolved in the melt. An anode composed of the refractory metal is immersed in the bath. The article to be coated is immersed in the bath as the cathode, a platinum electrode is immersed ...

  • Refractory Metals: Tungsten and Tungsten alloys

    However, the atomic sizes of these metals are such as to preclude extensive interstitial solution, and they will not be considered. Alloying of tungsten (W) has been relatively less studied than of some of the other refractory metals. Most of the tungsten used thus far in aerospace applications has been in the unalloyed form, which is much ...

  • Symposium on metallurgy and technology of refractory metal ...

    Abstract During the past dozen years, refractory metal structural alloys have been advanced to commercial availability under the auspices of government-supported programs. Further technical progress is feasible, and is likely to be supported on a selective, need-oriented basis.

  • DUCTILE-BRITTLE TRANSITION IN THE REFRACTORY METALS ...

    Abstract >Ductile-brittle transition behavior occurs in the bodycentered cubic refractory metals niobium, molybdenum. tungsten, and chromium. The available data for vanadium suggest that brittleness at low temperatures is attributable a low-stress-rate hydogen embrittlement.

  • High–temperature positron annihilation and vacancy ...

    Sep 13, 2006· Abstract By means of the new technique of sealed–source specimens the Doppler broadening of the positron–annihilation γM line has been investigated in the refractory metals V, Kb, Ta, Mo and W between 4·2 K and the melting points. Tho ' high-temperature S ' characteristic for positrons trapped at vacancies in thermal equilibrium was observed for Mo and W.

  • Refractory metals - Wikipedia

    Refractory metals are a class of metals that are extraordinarily resistant to heat and wear.The expression is mostly used in the context of materials science, metallurgy and engineering.The definition of which elements belong to this group differs. The most common definition includes five elements: two of the fifth period (niobium and molybdenum) and three of the sixth period (tantalum ...

  • OSA | Optical properties of refractory metal based thin films

    There is growing interest in refractory metal thin films for a range of emerging nanophotonic applications, including high temperature plasmonic structures and infrared superconducting single photon detectors. We present a detailed comparison of optical properties for key representative materials in this class (NbN, NbTiN, TiN and MoSi) with texture varying from crystalline to amorphous.

  • Refractory Metal Composite Tips for Resistance-Spot ...

    Refractory Metal Composite Tips for Resistance-Spot Welding of Galvanized Steel A study of electrode life and failure mechanisms, using sintered metal inserts for longer service and more con­ sistent quality BY J. F. KEY AND T. H. COURTNEY ABSTRACT. An investigation was un­ dertaken to develop and test refrac­ tory metal-copper composites as ...

  • CALL STRACS - tms.org

    Refractory Metals 2019 This symposium provides a forum for the presentation of fundamental research advances and technological progress in the understanding, processing and applications of refractory metals. Refractory metals are generally defined as those metallic elements with melting temperatures in excess of 2123 K (1850 °C).

  • Formation of refractory metal nuggets and their link to ...

    Ca, Al-rich inclusions (CAIs) often contain numerous refractory metal nuggets (RMNs), consisting of elements like Os, Ir, Mo, Pt and Ru. The nuggets are usually thought to have formed by equilibrium condensation from a gas of solar composition, simultaneously with or prior to oxide and silicate minerals.

  • Abstract - adsabs.harvard.edu

    Abstract With the expansion of research and the development of commercial production of refractory metals it has become possible to broaden the use of molybdenum, niobium, and other refractory metals in various branches of industry. In the near future we will have molybdenum alloys with a ductile-brittle transition temperature below room ...

  • Additive Manufacturing of Refractory Metal Alloys Through ...

    Abstract Refractory metal alloys are essential materials in many defense and aerospace applications including missile and rocket thruster nozzles, valves and manifolds. This is due to the extremely high melting temperatures of these materials (> 4000 F), high hardness and a resistance to heat and wear.

  • Powder Processing of Refractory Metals and Alloys | MRS ...

    For the past century the processing of refractory metals and alloys has been linked to powder metallurgy (P/M). A firm understanding of processing has been critical to attaining the desired performance levels. Although the consolidation science is in good shape, the availability of tailored powders with appropriate attributes is a limitation.

  • Abstract: Electrodeposition of Refractory Metals from ...

    Electrodeopostion of refractory metals from ionic liquids, including tantalum and niobium, has received a great deal of attention due to the potential of these coatings for a wide range of industrial applications.

  • Magnetic properties of the melt-textured (Nd,Eu,Gd ...

    Magnetic data measured on (Nd 0.33 Eu 0.33 Gd 0.33)Ba 2 Cu 3 O y with 35 mol% of Gd-211 (70 nm size), 1 wt% Ag, and 0.1 mol% of TiO 2, Nb 2 O 5, and MoO 3 (all 10 nm grain size) were analyzed. These composites exhibited very high critical current density, qualifying them to be the best candidates for use as bulk superconducting magnets.

  • Refractory metals as core materials for Generation IV ...

    Refractory metals and their alloys have high operation temperature range, because of superior high-temperature strength, and have been considered as candidate materials for the He or Na coolant options of Generation IV nuclear reactors.

  • High Temperature Creep and Fracture Behavior of the ...

    Abstract. The creep properties of the pure, polycrystalline refractory metals are reviewed and summarized. The creep behavior of all the pure metals is correlated in terms of their diffusivities and elastic moduli following the Sherby-type analysis.

  • Metals | Special Issue : Refractory Metals and Alloys

    Focussed specifically on refractory metals (Nb, Ta, Mo, W and Re) and their alloys, this issue seeks papers concerning the latest developments in their high temperature properties, corrosion resistance, and strengthening mechanisms including carbide, precipitate, solid-solution and dispersion ...

  • Oxidation studies of some refractory metals

    Oxidation studies of some refractory metals Abstract Samples of niobium, tantalum, molybdenum and tungsten metals have been given phosphided cases by heating in a phosphorous atmosphere. The samples were subsequently exposed to air at an elevated temperature. In tests at 800°C, the phosphided samples resisted air oxidation markedly compared to ...

  • Refractory Metal and its Preparation - scientific.net

    The General Status of the Refractory Metal was Reviewed Including its Characteristics and Application. the New Technology Research of Directly Prepared Refractory Metal from Refractory Metal Oxide was Discussed. FFC, OS and SOM Methods were Mainly Introduced. at the same Time, their Advantages and Disadvantages and the Difference between each other were also Pointed out. the Development …

  • Handbook of Metal Injection Molding - 1st Edition

    Metal injection molding combines the most useful characteristics of powder metallurgy and plastic injection molding to facilitate the production of small, complex-shaped metal components with outstanding mechanical properties. The Handbook of metal injection molding provides an authoritative guide to this important technology and its applications.

  • Guide for authors - International Journal of Refractory ...

    Before You Begin The entire submission and review process for the International Journal of Refractory Metals and Hard Materials proceeds entirely online using the Elsevier Editorial System, which shortens publication times.. Prior to submitting your paper, please follow the instructions on manuscript preparation given below. Please note that you must have an e-mail address to use the online ...

  • "INVESTIGATIONS OF SOLID-STATE SINTERING BEHAVIOR OF ...

    Abstract. Refractory metals are commonly alloyed for improved corrosion resistance, thermal stability, and strength. In service, these alloys form highly stable oxides under mildly oxidizing conditions at relatively low temperatures.

  • Production of Refractory Metal Powders | Powder Metallurgy ...

    Abstract. Refractory metals are extracted from ore concentrates or scrap, processed into intermediate chemicals, and then reduced to metal, usually in powder form. This article discusses the raw materials needed and the processing steps for producing pure and alloyed refractory metal powders. The effects of processing conditions on the physical ...

  • The Properties and Uses of Refractory Metals and Their ...

    The work discussed concerns the refractory metals niobium, tantalum, molybdenum, and tungsten and alloys based on these elements. Recent results on intermetallic compounds that contain a refractory metal and composites that are made of refractory metals and their intermetallics are also presented.

  • (PDF) Refractory Metals and Alloys - ResearchGate

    Refractory Metals and Alloys. ... common definitions describe a refractory metal as metal. with a melting point equal to or greater than that of. ... Citation and abstract.

  • Welding of Reactive and Refractory Metals - Total Materia

    Welding of Reactive and Refractory Metals Abstract: ... The reactive and refractory metals were originally used in the aerospace industry and are now being welded for more and more requirements. These metals share many common welding problems and are, therefore, grouped together. ... The refractory metals all have extremely high melting points ...

  • Nanoporous oxides of refractory metals: fabrication and ...

    Abstract A new approach to fabrication of nanoporous oxides of refractory metals is presented. It is based on the magnetron co-sputtering of aluminum and refractory metal (titanium, niobium or tungsten) followed by porous electrochemical anodization of the composite film and selective etching of alumina.

  • Refractory Metals and Alloys | Properties and Selection ...

    Abstract. All refractory metals, except osmium and iridium, have the highest melting temperatures and lowest vapor pressures of all metals. This Article discusses the commercial applications, and production procedures of refractory metals and alloys. These procedures include fabrication, machining, forming, cleaning, joining, and coatings.

  • The Powder Metallurgy Processing of Refractory Metals and ...

    PDF | Molybdenum and tungsten are refractory metals in the elemental form with the largest production volume in the world. The fabrication of these refractory metals, as well as their alloys and ...