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By Pinai Mungsantisuk

Keywords: Pd-Ni alloys, Pd-Fe alloys, Pd-Co alloys, Magnetostriction, Magnetic Properties The presence of congruent melting minima, the occurrence of ferromagnetic transition over a large composition range, and FCC type crystal structure make Pd-Ni, Pd-Co, and Pd-Fe based systems attractive candidates in our search for materials with no rare-earths, large low-field magnetostriction, and good mechanical properties. The presence of paramagnetic-ferromagnetic transition over a broad range of composition also provides opportunity for fundamental studies. In this work, we have examined the magnetic and magnetostrictive behavior of Pd-Ni, Pd-Co, and Pd-Fe alloys over the entire composition range. Alloy sample rods were prepared by arc melting and casting. X-ray diffractometer was used to obtain lattice parameter data. Magnetostriction was measured along the rod axis using strain gages. Magnetic properties were measured using a vibrating sample magnetometer.

Jan 1, 2005

By Purushottam Kumar

Keywords: Magnetostriction, magnetic properties, Pd(Fe,Co,Ni) single crystals Fe-Pd, Co-Pd and Ni-Pd alloy systems show appreciable magnetostrictive strains that are of interest for sensor applications. These systems exhibit congruent melting minima. In this work the magnetic and magnetostrictive behavior of congruent melting Fe-Pd, Co-Pd, and Ni-Pd compositions have been examined. The alloys examined include Fe-54.9 at.-% Pd, Ni-45.4 at.-% Pd, and Co-45 at.-% Pd. The paper describes the growth of bulk single crystals of these alloys using Czochralski technique. X-ray diffractometer was used to obtain rocking curves that were used to determine the [001] crystal direction. Magnetostriction in [001] direction was measured using strain gages. Magnetic properties were measured using a vibrating sample magnetometer. Ni-Pd showed the highest magnetostriction values among the congruent melting compositions. Magnetic and magnetostrictive behaviors of these alloy single crystals are presented.

Jan 1, 2005

By Ailton da Silva Ferreira

Thermoset polymers, like the polyester, become harder with increasing temperature owing to molecular crosslink formation, which is a thermal benefit for composite matrix applications. Natural lignocellulosic fibers, however, have low thermal resistance and tend to degrade with increasing temperature. Therefore, the combination of a lignocellulosic fiber, as reinforcement, with a thermoset polymer, as the matrix, results in a composite material with complex thermal behavior. In the present work, a thermal analysis was conducted on polyester composites with different amounts of curaua fibers. Both TGA and DTG curves were analyzed to determine the effect of the curaua fiber on the thermal resistance of the composites. It was found that the curaua fiber sensibly affects the thermal behavior of the polyester matrix for fiber amounts above 10% in volume. This effect is associated with an increase in thermal degradation.

Jan 1, 2010

By John R. FitzPatrick

The separation and purification of uranium from either nitric acid or hydrochloric acid media tan be accomplished by using either solvent extraction or ion-exchange. Over the past two years at Los Alamos, emerging programs are focused on recapturing the expertise required to do limited, small-quantity processing of enriched uranium. During this period of time, we have been investigating ion-exchange as a method for extraction/purification of uranium from acidic media. In addition, waste stream polishing is associated with this effort in order to achieve more complete removal of the uranium prior to recycle of the acid. Extraction chromatography has been demonstrated' to further polish the uranium from both nitric and hydrochloric acid media thus allowing for a more complete recovery of the actinide material and creation of less waste during the processing steps. We will discuss contact experiments for evaluation of eleven different resins for uranium removal from nitric acid, the evaluation (again by contact experiments) of uranium elution from the ion-exchange media by various chemicals, and small-scale experiments for the removal of 235U from nitric acid. Larger-scale (100-gram) flow experiments using depleted uranium, were done after the small-scale evaluation Of the selected resin. A discussion is also included concerning the shortcomings of the contact experiments and how the flow experiments were modified in order to overcome these problems. We will also discuss the application of ion-exchange for some specific process needs at Los Alamos Contact experiments were used to evaluate some commercially available solvent-impregnated resins in addition to evaluation of several resins of this type synthesized in our laboratory. These experiments' involved both nitric and hydrochloric acid media. The data from these experiments will be used to determine the column size and' amount of resin required to polish the waste stream produced by the ion-exchange process described above. Small-scale flow experiments will be described and data given on the mass balances achieved using this two step process. Future work for evaluation of new ion-exchange and solvent-impregnated resins as well as the search for new eluants will be discussed. Other future experiments for both processes, including large-scale experiments, will be discussed in detail.

Jan 1, 1996

By Ryan Walton

The Flash Converting Furnace at Kennecott Utah Copper converted over 465kmt of high-grade matte in 2002 but was restricted due to low matte production to 395kmt in 2003. This paper presents updated operational performance data and describes improvements implemented since the mid 2001 rebuild. Matte burner feed distribution, silica and arsenic impacts on settler lime-based slag operability, blister laundering, uptake/boiler accretion control, and dust sulfation will be discussed, as well as current development requirements dictated by operational imperatives and furnace modification plans.

Jan 1, 2005

By A. M. Strachan

Capper Pass & Son Limited Was, until its recent closure, the world's largest producer of tin from secondary materials including solder drosses, non-ferrous smelter flue dusts, tin based metal alloys, residues and slags. Polonium-210, an alpha emitting radionuclide, was present in varying concentrations in some of the numerous feed materials processed by the smelter and refiner. The polonium-210 followed a complex path through the process flowsheet. This paper discusses the behaviour of polonium, both from its arisings in other smelters' process streams and through the entire Capper Pass smelting and refining circuit. The consequential personnel safety and environmental precautions necessarily taken in some areas of the process operation are outlined.

Jan 1, 1992

A series of electron beam, cold hearth, single melt Ti-6Al-4V plates (nominally 2.5 cm thick) impacted by 2cm diameter, 4340 steel projectiles (with 54g nominal mass) at velocities ranging from 0.633 to 1.027 km/s were sectioned along the impact axis and examined by optical metallography to characterize the formation, growth, and microstructure of adiabatic shear bands. Near ballistic limit velocities, the shear bands propagate towards the rear of the target where they coalesce and grow to provide a cylindrical solid state flow regime for the plug volume.

Jan 1, 2006

By William A. Enrico

Umicore acquired the Pirdop Smelter in a privatization offering by the Bulgarian government in September 1997. Since that time, an investment program has been conducted to increase capacity to 225 000 tons per year of anode copper, while improving the environmental performance to meet Bulgarian and European standards. A significant part of this investment program involved reconstruction of the three Peirce-Smith converters and the associated gas handling system. During the period June, 2000 through April, 2002, converter capacity was increased, the existing water-cooled hoods were replaced, the waste heat boiler was replaced by two evaporative coolers, the dry ESP's were rebuilt and extended, and a Converter Control System (CCS) installed. From 2002 until the present, a continuous improvement of operating and environmental performance has been achieved. This paper will describe the converter reconstruction project, the operational, maintenance, and environmental improvements achieved since then and additional projects presently under consideration.

Jan 1, 2005

By M. T. Baquera

A comparison of microstructures associated with W single-crystal ([001], [011], [111]) rods prior to deformation (as grown), and after quasi-static compression (at a strain rate of ~1/s) by transmission electron microscopy (TEM) shows several orders of magnitude difference in dislocation density. Dislocation substructures were not significantly different amongst the deformed sample orientations. In contrast, [001] W rods penetrated into steel targets, at impact velocities of ~1.3 km/s, exhibited heavy dislocation densities and dynamic recrystallization as very distinct microstructural regimes accommodating the penetration process. Twinning on {112} also occurred as a precursor to, or remnant of, these microstructures near the projectile head. These results suggest that deformation accommodating the extreme strains and strain rates associated with the penetration of a single-crystal rod into a metal target is not adequately represented by conventional deformation

Jan 1, 2006

A molten metal granulator was designed and fabricated at the U.S. Dept. of Energy, Albany Research Center, for granulation of precious metal-bearing alloys and slags. The system was designed to safely granulate a metal alloy at a temperature of up to 1,600°C at a rate of roughly 50 kg of alloy per minute. The primary water jet was supplied by a 18.6-kW, 600 liter per minute pump which provided approximately 600 kg of water per minute through the primary jet. Two 3.7-kW, 150 liter per minute auxiliary pumps provided additional wash water to wet the granulation trough through 4 secondary jets, which were placed at either side of the primary jet. The water supply was closed-loop, including a 37,850-liter supply tank and 22,710-liter recovery tank. Magnetic separators and particulate filters were included for collection of the finest fraction of the granulation product, which cleaned the water sufficiently for continuous recycle.

Jan 1, 2006

By Elli Nurminen

In this work the thermodynamics of the metallic sulphate decomposition reactions were studied through thermodynamical calculations and thermogravimetric methods. The decomposition temperatures and mechanisms were determined for cupric sulphate, ferric sulphate and also for industrial flue dust from a copper flash smelting process. The aim was to determine the thermodynamic conditions for sulphate decomposition and to estimate whether the reactions are kinetically likely to take place in the flash smelting process heat recovery equipment. The information is essential in CFD-modelling of the reactions taking place in the boiler and for optimising the process.

Jan 1, 2006

By Y. F. Liang

Fe-6.5wt.%Si alloy has excellent soft magnetic properties compared with conventional silicon steel. It is very brittle at room temperature due to appearance of ordered phases, like B2 and DO3. In this paper, we investigate the effect of ordering on cold workability of this alloy. Methods of rapid quenching and hot rolling were utilized. It is found that rapid quenching and proper heat treatment of the hot rolled sheet could decrease the degree of order due to the very high solidification rate and high cooling rate. The rapid quenched sheet and hot rolled sheet after proper heat treatment could be cold rolled without crack. Microstructure, phase ordering, micro hardness, and cold rolling properties were investigated by Optical Microscope, X-ray Diffraction, Micro Hardness Indenter and Four-high Mill.

Jan 1, 2009

By R. Fragoudakis

AISI 4130 steel is a medium carbon Cr-Mo steel used in automotive, aeronautic and other general-purpose industries. In this study, 4130 steel fatigue specimens were carburized at 927oC to enhance the carbon content in the steel, raising it from approximately 0.30% (non-carburized) to 0.90% (carburized, oil quenched and tempered). Rotating bending fatigue tests were performed on the R. R. Moore Rotating Beam Fatigue Testing System, in order to determine the high cycle fatigue (HCF) life of 4130 steel and plot the corresponding S-N diagrams. A comparison of the results of carburized and non-carburized specimens shows that carburizing of steel: a) increases the surface hardness and b) improves the fatigue strength of the steel by at least two orders of magnitude.

Jan 1, 2010

By M. Potesser

One of the main targets in the automotive mass industry and supplying industry is the weight reduction of the vehicle for decrease of the fuel consumption. For that reason combinations of different kinds of materials and connections of, for example, steel and aluminium are developed or are already successfully field-tested. A determining factor concerning the quality assessment of the welded joint during hybrid welding is the characterization of the intermetallic Fe-Al layer regarding strength, hardness, morphology and mainly the different phases in which Fe occurs together with the Aluminum (FeAl, Fe2Al5, FeAl3.). A combination of conventional light microscopy, SEM - EDX - analysis, the usage of an atomic force microscope including a Nanoindenter and theoretical thermodynamic calculations turned out to be highly effective. Based on the attained results, the constitution of the intermetallic FeAl layer, influenced by silicon, manganese and zinc, can be predicted.

Jan 1, 2006

By Mishark Nnabuchi

A heterojunction of PbS - CuS thin film has been grown on glass slides by SGT. The films were annealed for 1hr at temperature of 373K and 423K respectively. The optical properties were characterized using a UNICO UV - 2102 PC Spectrophotometer at normal incidence of light in the wavelength range of 200 - 1000nm. The minimum percentage transmittance was observed to be 34% for sample A and 25% for sample B within the same optical region. The band gap energy was determined from the spectra to be 2.05eV for sample A and 1.85eV for sample B which gave a band shift of 0.20eV. It can thus be concluded that the optical properties of the films within the VIS - UV - NIR can find application in solar thermal technology, particularly as antireflection coating, window materials and as good materials for selective solar cell fabrication.

Jan 1, 2010

By A. M. Ramalho

In the synthesis and sintering processes to obtain superhard materials, such as diamond and cubic boron nitride, deformable ceramic capsule is used as gasket to transmit and support the required high pressures and high temperatures, HPHT. The ceramics materials for these capsules should have special physics and chemical characteristics such as refractoriness, shear strength and compressibility. In this work, Bridgman?s anvil made of hard metal or speed steel was used to characterize some ceramics materials in terms of their maximum compressible thickness. Tests were also performed with different resin polymers used as binding mixture with ceramics powder. Chemical analyses and investigations through scanning electronic microscopic (SEM), X-ray and real tests for the synthesis of diamond were also performed. The results showed that local Brazilian calcite can be successfully used in the manufacture of HPHT gaskets.

Jan 1, 2006

By Natalya. N. Ankusheva

The problems of ore-bearing palaevolcanic structures in folded belts are actual because of their high productivity in nonferrous, ferrous and noble metals ores. Now relationships of location and conditions of formation for sulfide-massive and gold-bearing deposits are investigated very well in Urals. But carboniferous sulfide-barite mineralization, for example the barite veins in Arcaimsky palaevolcano are?nt studied enough now [3-5]. The purpose of this research is the studying of mineralogy and thermobarogeochemistry of barite from the hydrothermal veins. It will allow to determine the conditions of its formation and to compare it to the similar mineralization of others ore types.

Jan 1, 2006

By S. Tanaka

The Tamano Smelter of Hibi Kyodo Smelting Co. Ltd. was commissioned in 1972. Since start up, the anode production capacity has increased from 101,000 tpy to 290,000 tpy, as a result of the application of continuous improvements at each phase of the expansion projects. The Tamano Smelter had developed several innovations, including the original coke combustion technology for Flash Smelting Furnace operations (T-FSF), and has also been able to extend the operating life of the Peirce-Smith converters. This paper will present several improvements implemented at the Tamano Smelter, and will discuss relevant P-S converter operation.

Jan 1, 2005

By Susan Jacob

The heat of fusion of silver was measured using high temperature differential scanning calorimetry (HTDSC). Heating rate, sample mass, calibration standard and cover gas flow rate were varied to determine their impact on instrument accuracy and reproducibility. Good reproducibility was achieved in most of the runs. Accuracy was not satisfactory in most of the runs, though three runs gave results within 1.7%, 3.3% and 3.5% of the literature value, within the acceptable limits. A larger mass and higher heating rate tend to generate more accurate results.

Jan 1, 2006

By Ram Avtar

High tensile thick plates (>80mm, weight ~3000 Kg) of medium carbon low alloy steel, when heat treated, manifested higher percentage of crystalline area (>20%) in fractured surface. Such problem was not encountered in thinner plates. The genesis of higher crystallinity in fracture was examined. It was observed that the thicker plate undergone slower rate (Average 0.9oC/Sec.) from soaking temperature to Ms temperature) of cooling after austenising during oil quenching and thereby quenched microstructure had upper bainites. During tempering of as quenched bainite, additional precipitation took place at the lath boundaries of bainite. This led to weakening of grain boundaries and aided easy crack propagation during fracture and resulted in formation of higher percentage of crystalline area in fractured surface. Enhancement in cooling rate (Average 1.8oC/Sec. from soaking temperature to Ms temperature) of austenised plate by switching over from oil quenching to water quenching practice resulted in complete transformation of austenite into martensite and produced ductile fracture (zero Crystallinity). Plates conformed improvement in mechanical properties between 2-5%.

Jan 1, 2009