Showing papers on "Liquid metal published in 1970"

Treatment of liquid metal

Abstract: A process for removing non-metallic constituents in molten metal, particularly aluminium and its alloys. In one treatment the metal is flowed through a multiplicity of flux-lined channels which are conveniently provided by a bed of flux-coated granules of a size such that the channels are large enough not to become clogged during use. In another treatment the metal is degassed by continuously passing it through a containing vessel while passing a substantially inert gas such as nitrogen therethrough under a flux cover; this can be followed by passing the metal through the flux-lined channels.

Q-Switched Laser Sampling of Copper—Zinc Alloys

Abstract: A more detailed knowledge than is presently available of laser beam–target material interactions is required if pulsed lasers are to be used with maximum effectiveness as analytical sampling devices. To this end. the Q-switched laser sampling of copper–zinc alloys has been investigated. Both vapor and liquid metal were produced in the sampling process. Observations of the crater dimensions and appearance showed that ablation of molten metal was the predominant material removal mode. It was demonstrated that the melting step was thermally equilibrated. Vaporization proceeded via a sequence of events wherein the vapor composition was independent of laser parameters, and could be predicted from the liquid-solid equilibrium diagram for the copper–zinc system. The effect of laser sampling on a subsequent chemical analysis is illustrated.

Liquid metal heat exchanger

Abstract: A liquid metal heat exchanger providing for a single pass of primary liquid metal and two passes of secondary liquid metal consisting of a removable core suspended at the top by an annular tube sheet clamped by a bolted ring for convenient removal. A funnel leading into a central downcomer separates cold incoming secondary liquid metal from the relatively hot outgoing secondary liquid metal.

Diagram Techniques for Determining the Conductivity of a Liquid Metal

Abstract: Diagrammatic perturbation techniques can be used to solve a general transport equation. These techniques are developed for the case of a correlated scattering system and the simple formula for the electrical resistivity of a liquid metal is obtained. Corrections to this formula are obtained in the form of a perturbation series whose convergence depends on the strength of the ion‐electron potential and the density of ions. The convergence of this series and the corrections it represents are investigated for the case of liquid sodium.

Liquid cooled x-ray tube anode

Abstract: The rotating anode of an X-ray tube used for medical examination is formed as a hollow member having a portion of its outer surface formed by an X-ray emitting metal and filled with liquid metal which evaporates to provide rapid cooling of the anode and permits operation with larger electron beam powers. The liquid metal is returned to the hot spot by centrifugal force. In one form of the anode a metal mesh is attached to the inner surface of the hollow member to retain liquid metal next to the target metal while the tube is cooling below the melting point of the liquid metal.

Penetration of refractory metals by alkali metals

Abstract: Under certain conditions tantalum and niobium undergo rapid penetration by liquid alkali metals along grain boundaries and certain crystallographic planes. Penetration is observed only when oxygen dissolved in the refractory metal exceeds some threshold concentration. This concentration depends upon the refractory metal, the alkali metal, and the temperature. Penetration was first encountered in niobium and tantalum exposed to lithium, but has now also been found to occur when these metals are exposed to sodium, potassium, and the sodium-potassium eutectic. Oxygen levels required to effect penetration in niobium and tantalum by lithium, sodium, and potassium at 600°C are compared, and the rate of penetration is discussed in terms of a corrosion model.

Measurement of the hall coefficient in liquid metals by the corbino method

Abstract: A new method for the measurement of the Hall effect in liquid metals is described, based upon the Corbino disc principle. It appears to offer considerable advantages for work at high temperatures. So far it has been applied to liquid Ga (used as a reference metal), Hg, Zn, Ag and Pb with results that are in good agreement with the best values reported previously. The results for liquid Pb suggest that the Hall coefficient in this liquid metal is 12% below the free-electron value.

Liquid Metal Embrittlement of Steel by Lead and Lead Alloys

Abstract: The loss of ductility of leaded steel when tested in tension at elevated temperatures is an example of embrittlement by a liquid metal in a system of major technological significance. Although leaded steels have been produced and employed for over thirty years because of their excellent machining characteristics, this lead-embrittlement was only recently documented and studied in any detail (1).

Liquid-metal arc switching device and process

Abstract: The electrical switch device has an envelope in which is mounted a force-fed liquid-metal cathode, an anode, a condenser which may or may not be subdivided for voltage grading purposes and, in the preferred embodiment, electrical shielding means for the condenser. The cathode is capable of very high electron-to-atom emission ratio. The required value for the electron-to-atom emission ratio is above 50 to 1. When arcing occurs from the liquid metal, a plasma jet of electrons, ions, and neutral particles is emitted from the arc spot. In addition, during arcing as well as non-arcing periods, some of the liquid metal evaporates from the cathode. This evaporation occurs into a much larger solid angle than that subtended by the plasma jet. The anode is mounted facing the cathode and it intercepts the plasma jet, thus permitting current conduction between anode and cathode with minimum voltage drop. The anode is kept at an elevated temperature, so that none of the ions and neutrals of the impinging plasma jet can remain condensed on it. They are immediately re-evaporated, including the ions after they have been neutralized. The condenser has a very much larger area than the exposed liquid metal area on the cathode, at least 100 times the exposed liquid metal area to dominate the equilibrium and it is kept at a low enough temperature to efficiently condense the liquid-metal vapor emitted by the cathode. With mercury used as the liquid metal, the condenser temperature is kept substantially below 0*, preferably at about -35* C, which is just above the melting point of mercury. The combination of the high electronto-atom emission ratio of the cathode with the large, low temperature condenser results in an equilibrium background pressure (i.e., pressure outside the plasma jet) of at least as low as 10 3 Torr during arcing and lower than 10 4 Torr during non-arcing periods. This low background pressure, in turn, permits the essentially unperturbed propagation of the plasma jet between the cathode and the anode surface upon which it impinges. Such a discharge mode is commonly referred to as a ''''vacuum arc''''. The fact that the plasma jet is emitted only during arcing and that the pressure within the space surrounding this jet is kept low, results in the ability to hold off electric fields up to 50 kV per centimeter between anode and cathode immediately after cessation of arcing. Arcing may cease because of a zero in the current fed to the switching device, as in conventional arc devices, or it may cease due to depletion of the liquid metal available for arcing on the surface of the force-fed cathode. In the latter case, the current fed to the switching device is forcibly interrupted. The process employs these characteristics for switching.

Antierosion feed slot for liquid metal collector

Abstract: In a liquid metal collector of the rotatable cup-type, the stationary member is provided with a segmented conductor blade such that a circumferential liquid feed groove and circumferential liquid pressure groove are formed between rings. At the bottom of each groove, respectively, a pressure pickup hole and feed hole are provided such that the proper level of liquid metal is maintained in the rotatable cup. By placing the pressure pickup hole and feed hole where the liquid metal velocity is relatively quiescent, erosion of the conductor ring at the discontinuities is prevented.

Production of metals from metalliferous materials

Abstract: IN A FURNACE SYSTEM, A PROCESS FOR SEPARATING AND RECOVERING A DESIRED META ELEMENT FROM METALLIFEROUS MATERIALS, SUCH AS ORES AND ALLOYS A LIQUID SLAG PHASE OF THE OXIDES OF THE DESIRED METAL ELEMENT AND MORE OXIDAIZABLE ELEMENTS AND A LIQUID METAL PHASE CONTAINING ARE CAUSED TO FLOW IN PATHS EXTENDING BETWEEN AND INCLUSIVE OF A METAL PURITY CONTROL ZONE AND A METAL RECOVERY CONTROL ZONE THE DESIRED METAL IN HIGH PURITY IS OBTAINED BY MAINTAINING A SLAG PHASE IN THE METAL PURITY CONTROL ZONE THAT IS RICH IN THE OXIDE OF THE DESIRED METAL MAINTAINING A METAL PHASE IN THE METAL RECOVERY CONTROL ZONE THAT CONTAINS PREDETERMINED CONCENTRATIONS OF THE MORE OXIDIZABLE ELEMENTS IN ONE IMBODIMENT, THE DESIRED METAL ELEMENT AND A MORE OXIDIZABLE METAL ELEMENT, BOTH CONTAINED IN A METALLIFEROUS MATERIAL ARE RECOVERED IN SEPARATE LIQUID METLA STREAMS FROM A SINGLE FURNACE IN IRON, MAY REQUIRE TREATMENT WITH A REACTIVE FLUX HE DESIRED METAL ELEMENT AND MORE OXIDIZABLE ELEMENTS BTAINING THE DESIRED METAL IN HIGH YIELD IS ENSURED BY HE REMOVAL OF CERTAIN IMPURITIES, SUCH AS PHOSPHORUS

The Solubilities of Several Transition Metals in Liquid Lead-Bismuth Eutectic

Abstract: Solubilities of cobalt, nickel, and chromium in liquid lead-bismuth eutectic have been obtained over the low temperature range 400 to 500 °C. Solubility equations and experimental heats of mixing have been calculated for these metals over the temperature range.

Liquid metal collector velocity divider

Abstract: Liquid metal collector is provided with a rotatable cup member and a stationary conductor blade. A floating ring is positioned generally intermediate between the blade and cup member and is immersed in the liquid metal such that is effectively reduces the rotational velocity of the liquid metal relative to the ring members by approximately one-half over the surface of the conductor blade. By so reducing the velocity of the liquid metal, power losses are reduced and antierosion characteristics are improved. A plurality of floating rings may be employed which will reduce the relative velocities even more.

Conductor blade for a liquid metal collector

Abstract: A liquid metal collector of the type having a stationary conductor blade immersed in a rotating volume of liquid metal has improved electrical characteristics through the incorporation of a circumferential groove which is positioned in the conductor blade so as to provide a relatively quiescent area of liquid metal. An annular pad of molybdenum may be positioned in the groove in order to further enhance the electrical characteristics of the liquid metal collector.

A review of NASA research to determine the resistance of materials to cavitation damage in liquid metal environments

Abstract: Cavitation damage resistance of iron alloys, nickel alloys, and cobalt alloys in liquid sodium and mercury - review of NASA program

Reactions of the oxides of niobium with liquid potassium

Abstract: The reactions of the oxides Nb2O5, NbO2, and NbO with liquid potassium have been studied at temperatures of 400°(Nb2O5) and 600°(all three). Reaction products are black, hygroscopic powders, which have been examined by X-ray powder crystallography. In each case the equilibrium products prove to be niobium metal and a low-temperature form of potassium orthoniobate, K3NbO4. The latter has also been prepared in a pure state, and its X-ray powder diffraction pattern defined. The co-existence of niobium in the Nb0 and NbV states in the product is discussed in the light of possible reaction mechanisms, and the stability of the MO4n– species in the liquid metal. Potassium monoxide also reacts with niobium metal at 260° to give K3NbO4.

Adsorption-Induced Embrittlement by Liquid Metals

Abstract: The prerequisites for the adsorption-induced embrittlement of an otherwise ductile solid metal by an active liquid metal are (i) a tensile stress, (ii) either a pre-existing crack, or some measure of plastic deformation and the presence of a stable obstacle to dislocation motion in the lattice, i.e. a concentrated tensile stress resulting in highly strained bonds across the potential fracture plane, and (iii) adsorption of the active embrittling species specifically at this obstacle and subsequently at the propagating crack tip (1–5). However, the factors that determine which liquid metal will actually embrittle which solid metal remain unclear. In general, it appears that to constitute an embrittlement couple, both the solid metal and the liquid metal should exhibit limited mutual solubility and little tendency to form intermetallic compounds. Dissolution processes are not thought to be relevant, because a suitably prestressed metal specimen will fail instantaneously on being wetted with an appropriate liquid metal, and presaturating the liquid metal with the solid metal does not influence embrittlement behavior significantly (6).

Dissolution of boron nitride in liquid iron

Abstract: The rate of dissolution of boron nitride in liquid iron and Fe-B alloys has been measured using a volumetric technique. The solution process was found to be diffusion controlled and directly related to the concentration of boron in the liquid metal. Diffusion control was substantiated further by experiments utilizing boron nitride rods which were rotated in liquid iron.

Electrical switch device having a fed liquid-metal cathode and a non-intercepting anode

Abstract: The electrical switch device has an envelope in which is mounted a liquid-metal cathode, an anode, and a condenser. The cathode is capable of very high electron-to-atom emission ratio. A desirable value for the electron-to-atom emission ratio is on the order of 100 or more and is attainable by means of a cathode such as disclosed in U.S. Pat. No. 3,475,636, when used in the switch device. The condenser has a very much larger area than the exposed liquid metal area on the cathode, and it is kept at a low enough temperature to efficiently condense the liquid-metal vapor emitted by the cathode. With mercury used as the liquid metal, the condenser temperature is kept substantially below 0 DEG C., preferably at about -35 DEG C. which is just above the melting point of mercury. When arcing occurs from the liquid metal, a plasma jet of electrons, ions, and neutral particles is emitted from the arc spot. The anode is mounted between the cathode and the condenser, and it is positioned at the edge of the plasma jet to capture the major portion of the electron flow for electrical conduction. Most of the ions and neutral particles as well as a sufficient number of electrons to preserve space-charge and current neutrality, pass the anode in the plasma jet and are captured on the condenser. The combination of the high electron-to-atom emission ratio of the cathode with the large, low-temperature condenser results in an equilibrium background pressure (i.e., pressure outside the plasma jet) of at least as low as 10 3 Torr during arcing, and lower than 10 4 Torr during non-arcing periods. These low pressures are obtained by maintaining the condenser in the range of low temperatures defined above. This low background pressure, in turn, permits the essentially unperturbed propagation of the plasma jet between the cathode and the surfaces upon which it impinges, i.e., condenser and anode. Such a discharge mode is commonly referred to as a "vacuum arc." The fact that the plasma jet is emitted only during arcing, and that the pressure within the space surrounding this jet is kept low, results in the ability to hold off electric fields up to 50 kV per centimeter between anode and cathode immediately after cessation of arcing.

Pressure Measurement Instrument for Liquid Metal Reactors

Abstract: The theory of operation and initial experimental results given in this paper pertain to a microwave frequency pressure sensor applicable to measurements within liquid metal cooled, fast breeder reactors. The basis of operation of the pressure sensor depends on the deflection of one end wall of a cylindrical microwave cavity and on the measurement of the resultant change of cavity resonant frequency. Temperature dependence of the sensor output signal is significantly reduced by measuring the difference frequency between two identical resonant cavities. The dual cavity (1.9-cm long by 3.3-cm diameter) sensor yielded nearly linear response over the temperature range 75 to 1200°F and for pressures up to one atmosphere, with sensitivities of 0.5 and 0.8 MHz/psi at 75 and 1200°F, respectively. The 0.015-cm thick stainless steel diaphragm also responded without permanent deformation for applied pressure of 45 psi. Pressure sensor time response to abrupt changes of pressure equals about 7.5 ms. The sensor and associated transmission waveguide fabricated of metal only should be immersible in the liquid metal coolant.

Sodium Vapor Deposition in Inert Enclosures

Abstract: Sodium vapor deposition is acknowledged to be a potential problem in several activities associated with Liquid Metal Fast Breeder Reactors (LMFBRs). Attempts were made to predict sodium evaporation rates using the empirical expression Nu = 0.643 (GrSc)0.25 developed for the evaporation of water. Small scale experiments were performed which indicate the general validity of this expression for sodium evaporation. The experiments also demonstrated that deposition of sodium within inert gas filled enclosures can be substantially reduced by circulating and filtering the atmosphere of the enclosure.

Corrosion by liquid metals : proceedings of the sessions on corrosion by liquid metals of the 1969 Fall meeting of the Metallurgical Society of AIME, October 13-16, 1969, Philadelphia, Pennsylvania

Abstract: 1. The Evaluation of Particulates Deposited in Flowing Non-isothermal Sodium Systems.- 2. Interaction Effects Between Dissimilar Metals in High Velocity Sodium at Temperatures up to 760 C. I. Mass transfer of Vanadium onto Type 321 Stainless Steel.- 3. Corrosion of Type 316 Stainless Steel with Surface Heat Flux in 1200 F Flowing Sodium.- 4. Sodium Corrosion of Westinghouse Liquid Metal Fast Breeder Reactor (LMFBR) Materials.- 5. The Corrosion of Stainless Steel in Oxygen-Contaminated Sodium at 1200 F and 1400 F.- 6. Evaluation of Materials-Compatibility Problems in the EBR-II Reactor.- 7. Radioactive Material Transport in Flowing Sodium Systems.- 1. The Effects of Exposure to Flowing Sodium on Vanadium Alloys in Stainless Steel Containment Systems.- 2. Application of Thermodynamic and Kinetic Parameters of the V-O-Na System to the Sodium Corrosion of Vanadium-Base Alloys.- 3. Corrosion of Oxygen Contaminated Tantalum in NaK.- 4. Penetration of Refractory Metals by Alkali Metals.- 5. Some Alkali Metal Corrosion Effects in a Rankine Cycle Test Loop.- 6. The Effects of Welding Atmosphere Purity on the Lithium Corrosion Resistance of Refractory Alloys.- 7. The Corrosion of Metals by Molten Lithium.- 1. Corrosion of Some Cobalt and Iron Base Alloys in Mercury.- 2. A 5000-Hour Test of a Eutectic Lead-Bismuth Circuit Constructed in Steel and Niobium.- 3. Diffusion Coatings Formed in Molten Calcium Systems. II. Variables in the System Ca-Cr-Fe.- 4. Corrosion Studies of Liquid Metal Heat Pipe Systems at 1000 to 1800 C.- 5. The Corrosive Action of Selenium Towards Various Materials in the Temperature Range 300 to 700 C.- 6. The Isothermal Corrosion (?+?) Ni-Sn Alloys in Pure Liquid Sn Component.- 7. An Anodic Treatment to Improve the Liquid Zinc Corrosion Resistance of Tantalum.- 1. Adsorption-Induced Embrittlement by Liquid Metals.- 2. Liquid Metal Embrittlement of Steel by Lead and Lead Alloys.- 3. Solid State Inhibition of the Liquid-Metal Embrittlement of Silver.- 4. Crack Initiation in the Zinc-Mercury Embrittlement Couple.- 5. The Grain Boundary Grooving of Iron in Liquid Sodium.- 6. The Solubilities of Several Transition Metals in Liquid Lead-Bismuth Eutectic.- 1. Oxidation-Reduction Reactions for Chromium and 304 Stainless Steel in Liquid Sodium.- 2. Solubility and Reactions of Oxygen in Sodium.- 3. Thermochemistry and Solution Chemistry in the Sodium-Oxygen-Hydrogen System.- 4. Measurements of the Solubility of Iron and Chromium in Sodium.- 5. The Segregation of Impurities and Particles in Sodium Systems.- 6. The Corrosion of and Mass Transfer of Pure Iron, Nickel, Chromium, and Cobalt in 660-760 C Sodium.- 7. Solubilities of Molybdenum, Tungsten, Vanadium, Titanium, and Zirconium in Liquid Potassium.

The Grain Boundary Grooving of Iron in Liouid Sodium

Abstract: When a polycrystalline metal is annealed at a sufficiently high temperature, grain boundary grooves are produced at the intersection of the grain boundaries with the metal surface. The grooves are formed by surface-tension-driven mass transport and have a profile as indicated schematically in Fig. 1. With the development by Mullins(1,2) of a theory of grain boundary grooving, it has been possible to distinguish between the mass transport mechanisms of surface and volume diffusion and to determine the diffusion coefficient. In recent years many studies of surface self-diffusion of metals have been performed by measuring grooving kinetics in vacuum, hydrogen, or inert gas environments.(3) Relatively few such studies have been made in a liquid metal environment and none, to the authors’ knowledge, in liquid sodium. Because of the use of sodium as a reactor coolant and the interest in its behavior as a corrodent, a study of grain boundary groove development on α-iron (b.c.c.) surfaces exposed to liquid sodium is currently underway in this laboratory. The purpose is to determine the mass transport mechanism and diffusion coefficient for a-iron in a sodium environment and to compare these results with those of surface self-diffusion of iron in vacuum.(4) Interference microscopy is being used to determine surface topography. The experimental program is nearly complete, and preliminary results of the study are presented here. Open image in new window Fig. 1 Schematic cross section of a grain boundary groove.

Failed fuel performance in naturally convecting liquid metal coolant.

Abstract: The results of an experiment are described in which two fuel specimens containing mixed oxide (Pu, ., , Uo .7 s)02 were irradiated in NaK cooled natural circulation capsules in the GETR at power and temperature conditions in excess of those expected in current LMFBR designs. Both of the specimens failed at < 18,000 MWd/Te. One of the specimens was immediately removed from the reactor after failure while the other,was permitted to continue irradiation to 53,000 MWdfle. Observation of both failed fuel pins showed significant transverse dimensional changes and fuel-cladding reaction.

Method for producing a material for use in the manufacture of oxygen electrodes for use in fuel cells

Abstract: A METHOD FOR TRANSFORMING LIQUID METALS OR ALLOYS SUCH AS AN AMALGAM OF INDIUM INTO A POWDERY MATERIAL INCLUDES THE STEPS OF RABBING OR STIRRING THE LIQUID METAL OR ALLOY IN AN OXYGEN ATMOSPHERE TO FORM A VISCOUS FOAM, AND INTRODUCING THE FOAM THUS FORMED INTO WATER WHICH IS BROUGHT TO BOIL WHERE THE GAS IS RAPIDLY RELEASED TO TRANSFORM THE LIQUID METAL OR ALLOY INTO FINELY DIVIDED PARTICLES. NEXT, THE PARTICLES ARE FILTERED AND DRIED. THE RESULTANT MATERIAL IS SUITABLE FOR USE WHEN COMPRESSED AND DISPOSED IN A STAINLESS STEEL CONTAINER AS AN OXYGEN ELECTRODE FOR A FUEL CELL.

Apparatus for reception and discharge of liquid metal

Abstract: A heating means and a feed container having a feed cavity therein are both coupled to a container which is adapted to receive and discharge liquid metal. The reception and discharge container includes a valve operated opening for selectively pouring out the liquid metal. A feed channel is provided between the lower end portions of the feed cavity and the container cavity such that liquid metal poured into the feed cavity flows into the container cavity through the feed channel. The feed container has a wall the height of which is equal to the maximum level of liquid metal in the container cavity such that when the liquid metal reaches the desired maximum level, the excess liquid metal is poured off over the wall.