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By Kunihiko Takeda, Kimio Imaizumi, Tsuyoshi Arai

"The study on the preparation of mono-dispersed liquid droplet was performed using ultrasonic as one of the steps of producing the perfectly mono-dispersed particle. The ultrasonic system was a 33.6kHz ultrasonic generator, an amplifier, an electric distortion element, and a bolted Langevin type horn installed in .a cell. For the first time, a liquid pillar under a nozzle of the cell ·was stably formed. Then, dense and coarse parts were alternatively constructed by oscillating the wavelength of the ultrasonic.· The diameter of those liquid droplets were found to be· perfectly uniform, therefore, it was measured by ""multiplex photography"" using a synchronized stroboscope with the ultrasonic.- From the results, more than 30,000 of perfectly uniform liquid droplets in 1 second were observed by this method.IntroductionRecently, research on the control of physical form is done in various fields of industry. Some examples are the processing technology of the minute compound material of micro-machines and integrated circuits, and the form control of molecule size like catalysts. There is a need for such material to take on various forms in correspondence to its use. ""Form control"" as used in this study will indicate ""research on physical chemistry factors which determine the size of the material"" and will refer to the contour uniformity of comparatively little particles. A well-known method of preparing particles is to spout a mist of liquid and slurry from a nozzle l) 2). Particles for metals, catalysts and food have been prepared by this method. In this case, although an approximate particle diameter can be decided by controlling the nozzle diameter and the violent outflow velocity, it is not easy to completely control ·the contour and to prepare a particle with uniform diameter. ·However, the preparation of perfectly uniform particles is necessary for solders for the adhesion of electronic wiring 3), ion exchange resins4), catalysts and so on. Large quantities of fine particles and super-fine particles are generated when manufactured in the usual way. Large quantities of these fine· particles and super-fine particles have polluted the internal and external' environments of factories. The products yield' ·decreases, also. From such a background, this study examines the preparation of perfectly uniform particles that could be· collected -100% as products. Recently, NASA has succeeded in the preparation of perfectly uniform particles in zero gravity 5). But the preparation of 'perfectly uniform particles by this method is difficult, and it can not be used in general industry"

Jan 1, 2000

By B. Yawney

A copper-nickel sulfide concentrate was leached in water at about 2000C under oxygen pressures of about 0.35 MPa. Oxidation of sulfide to sulfate was virtually complete in about 30 minutes, resulting in greater than 95% copper and 98% nickel extractions. Leaching temperature was shown to be the most important factor affecting metal extractions. Measured rates of oxygen consumption were used to develop batch kinetic data. Mini-plant continuous pressure leaching tests agreed with batch leach results. A proposed overall flowsheet is briefly examined.

Jan 1, 1976

By Viktor. P. Popov, Oleksandr. V. Derev'yanko, Oleksandr. I. Raychenko

"This paper is devoted to scrutiny problem of obtaining electro-contacts by electro-discharge sintering technology. A new unconventional method of electro contacts production (on Aggraphite base) can yield essential optimization resource.Review of three electro-technological methods of processing contacts materials is presented:- using graphite powder cladded by Ag;- mixture of graphite powder(which is a non-cladded powder) with Ag powder and addition of Fe powder particles;- method of infiltration of melted Ag into graphite piece without deformation and rupture of object.This technological approach can give the possibility to increase of compression strength of electro-contacts materials up to 340 MPa and more under conditions of additional reinforcing components (for example, by Fe).IntroductionThe electric current can be an active ""participator"" of the powder metallurgy technology [l]. At the passage of electric current through powders or some powder mixtures the phenomena including phase transformations arise. Here such effects, which are observed in the Ag-graphite and Ag-Fe-graphite powder mixtures and in the pair Ag-porous graphite, are described.The Ag-graphite composition materials (CM) are used, for example, as electric contacts [2, 3]. Since a material being produced is destined for the contacts it is necessary to take into account the following aspects: commutating current, its character and voltage, active or reactive character of working load, geometrical dimensions of contacts, quantity and frequency of switching on and switching off, pressure on contacts, distance between contacts, method of arc control, surrounding medium, its content, pressure and temperature. Thus, these and, maybe, choice of some other circumstances influence design, materials and production technology of contacts. The range of problems concerned dictates such steps as alloying of contact materials, optimization of structure, selection of kind of graphite, its connection with metal [4-10]. It is expedient to recall the main procedures of the first stage of the conventional technology: dosage of the initial graphite powder and binder-phenolic resin plastic varnish (for example, Bakelite), mixing, densification, thermal treatment, crushing, grinding, sieving, drying, dosage of grained graphite, dosage of the initial silver powder, obtaining of the silver salt solution, settling of salt, filtration, washing, drying of the cladded graphite powder, thermal treatment, obtaining of the graphite powder of particles cladded by silver. The second stage of the convectional technology starts by obtaining of the cladded graphite powder and finishes by annealing of the pressed blanks (Fig. 1)."

Jan 1, 2004

By Peter Willbrandt

The flash smelter at NA was commissioned in March 1972 with an initial throughput of 50 tons of dry copper concentrate per hour. As a result of various measures, for example, oxygen enriched process wind, extension of the radiation part of the waste heat boiler, etc., the throughput could be increased to the present 70 tons per hour of dry concentrate. NA's plant is located on the outskirts of the city of Hamburg. The flash smelter's location and the growing awareness of the German population as regards environmental issues necessitate again and again considerable capital expenditure being spent on environmental protection. Thanks to the numerous small and large measures taken to protect the environment the emissions of dust, heavy metals such as arsenic, copper, lead, etc., and as well SO, could be drastically reduced. This paper will be giving an overview on the present state of the flash smelting process and the impact of the increasing environmental awareness at NA.

Jan 1, 1993

By M. Bhattacharya, A. Dutta, P. Barat

"Pinning of dislocations at nanosized obstacles like precipitates, voids and bubbles, is a crucial mechanism in the context of phenomena like hardening and creep. The interaction between such an obstacle and a dislocation is often explored at fundamental level by means of analytical tools, atomistic simulations and finite element methods. Nevertheless, such studies fail to predict the effect on the overall plasticity on account of insufficient information about the underlying statistics of this process comprising a large number of dislocations and obstacles in a system. Here we propose a new statistical approach, where the statistics of pinning at idealized spherical obstacles is explored by taking into account the generalized size distribution of the obstacle along with the dislocation density within a three-dimensional framework. The application of this approach has been demonstrated for dislocation pinning at nanovoids in neutron irradiated type 316-stainless steel.IntroductionPresence of nanoscale obstacles like precipitates, voids and bubbles play a crucial role in determining the deformation behavior of a crystalline solid on account of the interactions between the line defects and such localized obstacles. In the context of the glide motion of dislocations, the obstacles can offer resistance to a moving dislocation, thereby causing a hardening effect [l-3]. In some other cases, inclusions like voids and bubbles can affect the rate of dislocation climb through diffusive [4] and non-diffusive [5] mechanisms. Over the last few decades, numerous studies have been performed to gain an insight of the dislocation-obstacle interactions at a fundamental level. These include the interactions responsible for the hardening effect, in addition to those pertaining to the non-conservative motion of dislocations.Although the elementary mechanisms of the various dislocation-obstacle interactions have been vastly explored and understood by means of analytical theory and numerical simulations, it remains difficult to quantitatively understand their effects on the macroscopic deformation behavior. This is due to the fact that their influence on the gross plastic deformation of a bulk sample would be the collective outcome of a large ensemble of such interactions. As a result, it becomes infeasible to predict the bulk deformation behavior of a material until the statistics of pinning of the dislocations at the localized obstacles is available. In the context of precipitate hardening, some well known attempts to extract the pinning-statistics were made by Friedel-Fleischer [6] and Mott [7] by analytical means, which were later tested through simplified 2-dimensional in-silica modeling [8]."

Jan 1, 2014

By Milton Manrique, Edgar E. Vidal, Patrick R. Taylor

"Ultrafine zirconium carbide powder has been synthesized using zircon concentrate and methane in a thermal plasma reactor. The effect of several experimental variables, such as power used and zircon particle size, on the conversion has been studied. A thermodynamic analysis of the possible reactions and stable compounds was performed. A mathematical model that describes the in-flight decomposition of zircon particles was developed based on a description of the temperature and velocity profiles calculated in the reactor. It was shown that the formation of zirconium carbide from zircon and methane is thermodynamically possible. Complete 'vaporization of zircon in the reactor is predicted when the particle size is below 45flm and the effective power entering the reactor is 15 kW. The powders were collected and characterized by XRD, SEM, TEM and chemical analysis using ICP. Results of the product analysis indicated the presence of zirconium carbide, zirconium oxide, silicon carbide and silicon oxide.IntroductionIn recent years there has been an increased interest in the production of nanometric sized powders of ceramic materials for use in advanced materials applications. One possible method to produce these powders is with a thermal plasma reactor, which offers high temperatures and fast quenching rates. This technology has been called - Thermal Plasma Synthesis - [1].Zirconium Carbide (ZrCx) has typical properties of transition metal carbides: elevated hardness - between alumina and diamond - a high melting temperature of 3420°C and high chemical stability at room temperature [2]. ZrCx has a Bl crystal structure with deficiencies in the number of carbon atoms in the cell with x between 0.6 and 1 [3]. Different methods have been used to produce ZrC, one method is by direct reaction of zirconium hydride or halide with carbon. Other methods used are direct reduction and carburization of zirconium oxide (Zr02) and reaction of metallic zirconium with a caburizing gas such as acetylene [3]. Recently small films of ZrC have been obtained using a sputtering device [4,5]. ZrC has been used in nuclear plants as a low neutron absorbing and high mechanical resistant refractory material and also as a constituent in cathodes made of UC-ZrC [6]. It is also used in the form of tubes, boats and crucibles to handle molten metals and as part of electronic devices used for thermoionic transducers. Recently ZrC has been used along with zirconium diboride (ZrB2) to produce composite materials [7,8]."

Jan 1, 1996

By J. L. Sanchez

Using a special double-zone transpiration reactor, the vapor transport chemistry of vanadium pentoxide in the presence of water vapor has been investigated. Three possible volatile hydroxides above V,O,(s) are reported in the literature: VO,(OH),, V,O,(OH),, and VO(OH),. In the present study, it was established that VO(OH), is the principal gaseous hydroxide species formed. The predominant reaction was found to be: { } The vapor pressure of VO(OH), was measured as a function of temperature, water pressure, oxygen pressure and flowrate. The results have been used to determine the Gibbs free energy of the above reaction as a function of temperature: { } The results of the present work were combined with thermodynamic data reported in the literature to obtain expressions for the AGO for the reaction above V,0,(1) and the AGO of formation (units in cal/g-mole).

Jan 1, 1993

By C. E. M. Meskers, U. Boin

"The increasing use of coated magnesium in consumer products results in creation of coated Mg scrap during product manufacture and after End-of-Life product treatment. Currently this material is generally not recycled, leaving a material resource unused. Closure of the magnesium cycle in a sustainable manner is necessary. In order to do so, the effect of coatings on the recycling process has to be quantified, predicted and minimized. For this purpose metrics have been developed, based on first principles supported by detailed understanding of the recycling process. The developed 3D metric enables quantitative assessment of the recyclability and links coating design, product design and recycling to each other in a visual manner. The parameters that form the metric can be measured and predicted, hence an engineering basis for Design for Sustainability of coated magnesium is provided.IntroductionEvery product progresses through the four phases of the product life cycle depicted by figure 1. In each phase residues are created. Their amount and composition is largely determined by the complex material combinations created/invented during product design in the manufacture phase. Compared to the ideal cycle the magnesium cycle is far from closed (fig. 2). Most noticeable is absence of the link between the EoL phase and raw materials production. A closed cycle only exists for class 1 scrap, which goes from the product manufacture phase directly to production from industrial material and returns to the manufacture phase as magnesium alloys. The four problematic streams are marked by ???. Coated semi-products are present in two of the four residues, namely in rejects and collected scrap. When these semi-products are recycled the amount and composition of the dross and salt slag residue is affected as well.During product design selection of the coating takes place, fixing the coating character¬istics and properties from this moment on for the rest of its life cycle. The choices made in the manufacturing phase are therefore critically linked to the recyclability of coated semi-products as well as the sustainability of the magnesium cycle as a whole. Sustainable closed life cycles, in which the quality of materials is preserved and residue creation and resource depletion are minimized, can be attained by selecting the appropriate alternative during product design. To realize this the effect of design choices on the life cycle and more specific the recycling process has to be known and quantified."

Jan 1, 2008

By A. P. Paiva

Although the advantages of Solvent Extraction for separation/purification of relatively concentrated solutions are well known in Extractive Metallurgy, its use for the recovery of elements present in low levels only recently has been discussed, with particular attention devoted to precious metals. In this work, the extraction behaviour of Cyanex 471X towards silver, from an acidic chloride medium is reported, the extraction and stripping isotherms and related kinetic features analysed. Results on the selectivity of silver extraction against high contents of iron, copper and lead are discussed. Phosphine sulphide extractants are generally associated with solvation mechanisms: analysis of the extraction pathways along with the possibility of reaching a suitable loading in the organic phase are also presented.

Jan 1, 1993

By A. W. Bryson, S. P. Fox, S. A. Godorr

"This work is an extension of a previous investigation on the development of surface roughness during electrodeposition of copper. A comprehensive model based on diffusion and migration in a force field together with surface diffusion and sticking probabilities is used to generate profiles which are compared to those produced experimentally. The roughness is characterized by using the technique of fractal geometry which is shown to describe both qualitatively and 9uantitatively the development of surface morphology during electrodeposition.The work is extended to the deposition of copper in the presence of various concentrations of thiourea. The development of roughness is observed experimentally on the edge of a thin copper disc mounted between two glass plates. This enables photographs to be taken at various stages during growth. The surface outline is digitized using an image analyzer which enables the fractal dimension to be determined as growth proceeds. As expected, the presence of thiourea at low concentrations produces a fractal dimension which is closer to unity (i.e. the surface becomes smoother).IntroductionThe development of surface morphology during electrodeposition has far-reaching implications for copper plating in the electrowinning and electrorefining processes. Short circuits as the cathode surface grows unevenly require operator intervention in a dangerous environment and imply processing delays, and the inclusion of electrolyte in small gaps in the plated cathode have implications in downstream processing of the cathode. Higher current densities are obviously desirable, as they result in greater production rates, but as shown by Ettel et. al.(l), Harvey et. al.(2), Cook (3), and Harvey et. al.(4), it is not possible to operate near the projected economically optimum conditions because the electrodeposition of copper from sulphate and acid solutions is a mass transfer controlled process. It has been shown (Ettel et. al.(l), Harvey et. al.(2)) that the closer a system operates to mass transfer limiting conditions, the poorer the resulting cathode quality. One solution is to use agitation techniques to increase the limiting current density. Another is to add surface active additives to the electrolyte which has been shown by Ettel et. al.(l), Harveyet. al.(2) and Afifi et. a1.(5) to allow higher rates of production without decreasing cathode quality. The second proposed solution is of interest in this work, since there is very little knowledge of the conditions under which these additives operate effectively, and little fundamental understanding of the mechanism by which they operate. The current work seeks to contribute to this field by correlating a simulation model with experimental results to describe the development of surface morphology in the electrodeposition process."

Jan 1, 1997

By Richard L. Summers

The shaped charge has proven in various military and industrial applications to be an effective penetrator of materials. Upon initiation a detonation wave traverses the explosive billet, collapsing a metallic liner and creating a jetting process. From multiple non-simultaneous flash radiographs of the jet in free flight, the observer can study the collapse, formation, and growth of a shaped charge jet. Digitization of a particulated jet's position and shape from the radiograph into electronic storage files provides the experimentalist with an efficient basis for data reduction. With the aid of a simple personal computer, one can in a matter of minutes generate a wealth of information concerning jet formation after initiation and thus gain insight into the quality of its manufacture, design, and assembly. This paper will in detail explain the methods in place for fully automated data reduction of radiographic films. Methods of computer aided digitization of particulated jets and analysis of physical jet characteristics and performance will be discussed.

Jan 1, 1992

By E. O. Stensholt

The Hybinette electrorefining process for production of cathode nickel was in use at Falconbridge Nikkelverk A/S, Norway, until 1975 when conversion to the new chlorine leach process was started. In 1978 the conversion to electrowinning had been completed, but further major improvements to the process have been made up to 1987. After a major expansion program in 1985 - 87 the refinery has a nickel capacity of 54 000 mt Ni/year. The main feed materials to the process are converter matte from the Falconbridge smelter in Sudbury, Ontario, Canada, and from the BCL smelter in Selebi-Phikwe, Botswana. A typical composition of the mixed feed to the refinery is: 40 - 45% Ni, 25 - 30% Cu, 20 - 22% S, 2 - 3% Fe and 1.0 - 1.5% Co. The matte is chlorine-leached in the first process step, nickel being dissolved selectively in a train of leach-cementation tanks. Essentially all copper and sulphur that was present in matte appears in the leach residue as CuS. In 1986 an autoclave treatment stage was added to the process to improve nickel extraction from the leach residue. The resulting strong nickel chloride solution is purified by the process steps (1) precipitation of iron and arsenic, (2) solvent extraction of cobalt and other minor elements and (3) precipitation of lead and the remaining impurities. The nickel solution is then fed to the tankhouse, where various nickel products are produced by electrowinning. The chlorine gas that is produced during the electrolysis is returned directly to the chlorine leaching tanks to dissolve more matte. After stripping from the loaded organic phase and solution purification cobalt is also produced by electrowinning. The copper sulphide leach residue, which contains some nickel, is dead- roasted in fluidized-bed roasters. The sulphur is recovered and sold as sulphuric acid. The calcine is leached in spent copper electrolyte, from which cathode copper is produced by electrowinning. Precious metals and the remaining base metals are recovered from the copper leach residue. The Falconbridge chlorine process is very versatile. It can accept a wide range of impurities in the feed and still produce metals of exceptional purity.

Jan 1, 1988

By Steven C. Torma

The present article reviews some of the technologies available for recycling high-energy yield explosives loaded projectiles. These activities lead to reduction of military ammunition stockpiles and their conversion into commercial and industrial applications. The recycling technologies involve dismantling and separation of ammunition components into recyclable metals, plastics, paper and explosive materials. The metal 1 ic components will be sent to smelters, where they will be converted to products that can be used in a variety of industries, such as construction, automotive, housing and so on. Plastics and paper will be recycled and reused. Explosives will be recycled to be used for industrial purposes in the mining industry. Propellants (ammonium nitrate and ammonium perchlorate) can be ground to small particle size and treated to be used in the agricultural industry as fertilizer. In addition, some of the excess explosive material recovered in the demilitarization process may be incinerated to produce energy for steam production for heating purposes, or for production of electricity. Furthermore, this article reviews the developments in the bioremediation of explosive contaminated soils and industrial effluents.

Jan 1, 1994

By Donald I. Bleiwas

World primary nickel production in 1987 is projected to be 770,000 mt, slightly higher than that in 1986. Market economy country (MEC) production in 1987 is projected to be about 524,000 mt, an increase of almost 5 pct over 1986 production. Production cutbacks and closures at Japanese ferronickel plants in 1987 resulted primarily from the strong yen and higher energy prices. Cutbacks also caused reductions in ore production from Indonesia, New Caledonia, and the Philippines. Technical problems affected production, to varying degrees, in Botswana, Indonesia, and Yugoslavia. World primary nickel production for 1988 is projected to be 787,000 mt, of which 536,000 mt will be produced in MECs. Increased production is projected from Botswana, Canada, Cuba, and possibly Greece and Yugoslavia, while slight production decreases are projected for Indonesia, New Caledonia, the Philippines, and Zimbabwe. .. South African nickel production in 1988 could be severly curtailed by social strife. In the early 1990's Brazil and China could be major economic competitors to Western nickel producers.

Jan 1, 1988

The present work is mainly focused on developing intermetallic inert anodes for aluminum electrolysis. The anode alloy based on Al-Ti-Cu system was prepared by casting, followed by the application of a protective coating. Behaviour of corrosion and the passivation under anodic condition was characterized using the electrochemical and microscopic techniques. The results obtained clearly demonstrate that the oxide coating can provide good corrosion resistance via surface passivation of alloy anodes, rendering them inert in cryolite melt.

Jan 1, 2006

By F. Sekula

Tetrahedrite and siderite are two main valuable minerals present in the silver Mária Bana deposit. The tetrahedrite concentrate prepared from it by flotation has certain specific properties from the metallurgical point of view. Siderite is concentrated in the flotation tailings. The paper presents results of the laboratory and pilot-plant testing of the combined hydrometallurgical and pyrometallurgical methods proposed for treatment of the tetrahedrite concentrate and siderite waste. The testing conditions were based on thermodynamic analysis of the reactions that proceed in the process. The proposed technology makes it possible to separate copper from sulphur, mercury and iron in a straightforward way. Copper, after its refining, can be subsequently treated in the finishing operations. At the same time it is a valuable source of precious and noble metals. The siderite-containing flotation tailings can be converted to iron of the technical purity and slag. The proposed method is a good starting point for the development of the closed-cycle technology.

Jan 1, 2006

By Y. Y. Sheng

Plume flows created by gas injection into liquid metals have been studied extensively, however the dynamics of bubbles within the plume have not received adequate attention, particularly for large, irregular bubbles, characteristic of the processing of liquid metals. The present model uses a combined Eulerian-Lagrangian approach in which an estimated void fraction distribution is used to calculate the liquid flow field with a conventional Eulerian scheme. The trajectories of bubbles are then computed in a Lagrangian manner using the estimated flow field, and experimentally measured information on bubble drag coefficients', lateral migration due to lateral lift forces and interaction with turbulent eddies, and variation in bubble size due to break-up. Turbulence in the two-phase zone is modeled with a modified k-e model with extra source terms to account for the second phase which have been recently determined by the present authors. The computed void fraction and turbulent liquid flow field distributions are in good agreement with experimental measurements.

Jan 1, 1993

By J. M. Toguri

The viscosity of the molten FeO-Fe2O3-Si0z system in the composition range of interest to copper smelting has been investigated using a rotating cylinder technique. The silica content of the slag was varied from 20 to 35 wt percent while the oxygen pressure of the system was varied from 10-7 10-11 atm. The temperature range investigated was from 1200 to 1350°C. It was found that the viscosity of the slag generally decreased with increasing temperature and increasing oxygen pressure. As the silica content was increased, the viscosity was found to increase.

Jan 1, 1976

By Caisa Samuelsson, Fredrik Engström, Bo Björkman, Margareta Lidström Larsson

"Large amounts of by-products are generated by the Swedish steel industry each year. The EAF-process generates about 400 000 ton of slag, from which 80% is deposit. An alternative to deposit is to use slag as road construction material. However, metal content in the slag can be a problem, due to the leaching. The aim of this work was to investigate how stable these materials are when ageing and kept outside. Five different EAF-slags from domestic steel plants were used in this study. The materials were characterised after 0, 6, 12, 18 and 24 month to evaluate the ageing process. Scanning electron microscope (SEM), x-ray diffraction pattern (XRD) and a standard test for leaching were used. The changes in behaviour differ between the five materials. The total leachability decreases with time for all samples. CaCO3 is formed on slag surfaces as CaO reacts with moister and CO2 in the air. Introduction The slag generation in the Swedish steel industry is about 1.5 million tonnes annually, of which more than 500 000 ton is generated in EAF (Electric Arc Furnace), AOD- (Argon Oxygen Decarburization) converters and during the refining of steel in the ladle metallurgy. Some of the slags are used in different applications, but most of the steelmaking slags produced in Sweden are landfilled today. The chemistry, mineralogy and physical characteristics of slags make it a suitable material in construction, replacing for example, gravel and rock [1]. In some respects, in road construction, it may even be technically superior to virgin material. Slag from scrapbased steelmaking is used for road construction in Europe. The reason for the low utilization in Sweden is mainly due to potential leaching of harmful elements, legislations and competition with easily available natural raw materials. Except the potential leaching, the technical obstacles for not using some slags in construction include:"

Jan 1, 2008

By Damien Wagner

To reduce the emission of greenhouse gases by the steel industry, particularly for ironmaking, the production of DRI (Direct Reduced Iron) using hydrogen as the reducing gas instead of carbon monoxide is being considered. In this context, the reduction of pure hematite by hydrogen was studied at the laboratory scale, varying the experimental conditions and observing the rate and the course of the reaction. All the reduction experiments were performed in a thermobalance and supplementary characterization methods were used like scanning and transmission electron microscopy, X-ray diffraction, and Mössbauer spectrometry. The influence of rising temperature in the range 550-900°C is to accelerate the reaction; no slowing down was observed, contrary to some literature conclusions. A series of experiments consisted in interrupting the runs before complete conversion, thus enabling the characterization of partially reduced samples. Interpretation confirms the occurrence of three successive and rather separate reduction steps, through magnetite and wustite to iron, and illustrates a clear structural evolution of the samples. Finally, the influence of the sample type was revealed comparing a regular powder, a nanopowder and a sintered sample. The regular powder proved to be the most reactive despite its larger grain size, due to a more porous final structure.

Jan 1, 2006