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Base Metals Waste Production and Utilization
Published in Sehliselo Ndlovu, Geoffrey S. Simate, Elias Matinde, Waste Production and Utilization in the Metal Extraction Industry, 2017
Sehliselo Ndlovu, Geoffrey S. Simate, Elias Matinde
Nickel is a transition metal element with a face-centred cubic lattice across the entire solid temperature range, atomic number 58.71 and electronic configuration [Ar]3d84s2 (Davies, 2000). The melting point and density of nickel are 1453°C and 8902 kg/m3, respectively (Davies, 2000; BGS, 2008). In its solid state, nickel is a lustrous, silvery-white metal, which is hard, ductile and malleable, and can take a high polish (BGS, 2008). In addition, the thermal and electrical conductivities of nickel are fairly low, and it can easily be magnetized (Davies, 2000; BGS, 2008). In other words, nickel is strongly ferromagnetic at ambient temperatures, and as a result, special nickel-containing alloys have found widespread applications in the manufacture of different grades of magnets, ranging from high-permeability and soft magnetic alloys to high-coercivity, permanent magnet alloys (Davies, 2000). Other important properties peculiar to elemental nickel include resistance to oxidation and to corrosion attack by alkalis, high-temperature strength properties and high alloyability properties with other metals (Davies, 2000; Total Materia, 2001; BGS, 2008). Furthermore, nickel has typical metallic properties, which means it can easily be rolled, drawn into wire, forged and polished (Davies, 2000; Total Materia, 2001).
Magnetic Materials
Published in John Bird, Newnes Engineering Science Pocket Book, 2012
Nickel and iron are both ferromagnetic elements and when they are alloyed together in different proportions a series of useful magnetic alloys is obtained. With about 25%-30% nickel content added to iron, the alloy tends to be very hard and almost nonmagnetic at room temperature. However, when the nickel content is increased to, say, 75%-80% (together with small amounts of molybdenum and copper), very high values of initial and maximum permeabilities and very low values of hysteresis loss are obtainable if the alloys are given suitable heat treatment. For example, Permalloy, having a content of 78% nickel, 3% molybdenum and the remainder iron, has an initial permeability of 20 000 and a maximum permeability of 100 000 compared with values of 250 and 5000 respectively for iron. The maximum flux density for Permalloy is about 0.8 T. Mumetal (76% nickel, 5% copper and 2% chromium) has similar characteristics. Such materials are used for the cores of current and a.f. transformers, for magnetic amplifiers and also for magnetic screening. However, nickel-iron alloys are limited in that they have a low saturation value when compared with iron. Thus, in applications where it is necessary to work at a high flux density, nickel-iron alloys are inferior to both iron and silicon-iron. Also nickel-iron alloys tend to be more expensive than silicon-iron alloys.
Bio-Based Magnetic Metal-Organic Framework Nanocomposites
Published in Anish Khan, Mohammad Jawaid, Abdullah Mohammed Ahmed Asiri, Wei Ni, Mohammed Muzibur Rahman, Metal-Organic Framework Nanocomposites, 2020
Manickam Ramesh, Mayakrishnan Muthukrishnan
The human body comprises numerous cells and constant movement of ions within and outside cell membranes and results in electrical activity which forms the basis of biomagnetic fields that can be measured by external instruments placed outside our body. Biomagnetism involves the study and manipulation of these biomagnetic fields. Generally, prior to usage of magnetic MOFs, magnetic materials are widely used in the medical field in the areas like cell separation and magnetic resonance imaging (MRI). Some of the prominent magnetic biomaterials are magnetic alloys of Fe, Co, Ni, Nd-Fe-B, etc. The choice of the materials is limited by biocompatibility issues and toxicity limits. However, biocompatibility of these materials can be enhanced by encapsulation of these magnetic alloys as magnetic metal cores and form shells using biocompatible polymers. These core-shell combinations which possess coercivity, high magnetization, and better susceptibility are suitable for developing magnetic MOFs which are place in the medical field owing to their molecular storage capabilities, separation, delivery, and enzymatic biocatalysis. Thus, by manipulation of the above properties, biomagnetism can be achieved by altering the composition of the core-shell combination, temperature, crystal structure of MOFs, pressure, and by varying the size of the microporous material. Recent researchers have tuned MOF pore environments for the adsorption of biomolecules into a porous framework of MOF crystals and modified it as a protein-enabled MOF surface. It also paves way for effective drug delivery systems by host guest encapsulation and other interactions with effective responsiveness.
Selective preparation of samarium phosphates from transition metal mixed solution by two-step precipitation
Published in Environmental Technology, 2022
Rare earths are used in a variety of functional materials, and their supply to industry needs to be stabilized [8,9]. Rare earth ores are known to be localized and often contain radioactive elements [10]. Due to the mixture of radioactive elements, mining of rare earths poses strong environmental problems, so it is useful to recycle rare earths from scrap and magnet waste as urban mines [11]. Several processes for rare earth recycling have been reported, e.g. solvent extraction using dilute ionic liquids to remove transition metals from rare earth elements [12,13]. However, a drawback of this process is that it requires high concentrations of acid and special reagents. In other methods, samarium has been recovered from samarium-cobalt magnetic alloy sludge by chemical vapor phase transport [14,15]. However, this method also has drawbacks, requiring high temperatures and specialized equipment. Based on the study of these processes, it is hoped to develop a new recovery process that overcomes the above drawbacks.
Fabrication of high magnetic performance Fe–50Ni alloy by powder injection molding
Published in Materials and Manufacturing Processes, 2020
Muhammad Ali, Faiz Ahmad, M. R. R. Malik, A. R. Niazi
There was considerable improvement in density with enhancing sintering time. The sintered density achieved 96.12% and 96.94% at 4 and 6 h of sintering, respectively. The density enhanced up to 14 h of sintering and then became constant, and after that, there was no considerable improvement. The maximum sintered density of 98.02% was achieved. The density values at different sintering times are shown in Fig. 10. As the sintering time increased from 4 to 6 h, the reduction in porosity showed a significant effect on grain growth, and grain size was enlarged from 110 to 135 µm. The twinning phenomenon occurs during the austenite phase formation. The twinning can be clearly seen in the microstructure of the Fe–50Ni soft magnetic alloy. The density was enhanced to 97.94% when the time was enhanced to 10 h. Initially, the specimen has a significant amount of porosity, but it gradually decreased with progressing sintering time. The particle size affects the densification and microstructure, considerably. The significant grain growth occurred due to the elimination of porosity as the sintering time was prolonged. The grain size was enlarged to 180 µm, but still, there was some porosity at grain boundaries and within the grain boundaries. The densification of test samples was enhanced until 14 h of sintering and after that the density became constant and there was no considerable improvement. The sintered density obtained after 12 h was 98.00% and just increased slightly 98.02% after 14 h, whereas the grain size was 210 µm at 12 h and improved to 220 µm at 14 h of sintering.
A comparative study of the influence of the deposition technique (electrodeposition versus sputtering) on the properties of nanostructured Fe70Pd30 films
Published in Science and Technology of Advanced Materials, 2020
Matteo Cialone, Monica Fernandez-Barcia, Federica Celegato, Marco Coisson, Gabriele Barrera, Margitta Uhlemann, Annett Gebert, Jordi Sort, Eva Pellicer, Paola Rizzi, Paola Tiberto
Morphology and stoichiometry of the films were studied using atomic force microscope (AFM), scanning electron microscope (SEM, FEI Inspect F) and transmission electron microscope (TEM, Jeol JEM-3010). The latter was equipped with an energy dispersive X-ray spectrometer (EDS). The crystallographic structure of the films was investigated by grazing incidence X-ray diffraction (GIXRD) on a Panalytical X’Pert PRO MPD using the Cu Kα radiation, at a grazing angle of 0.4º. The magnetic properties were investigated using avibrating sample magnetometer (VSM) from Lakeshore, at room temperature, up to a maximum field of 20 kOe. Magnetic force microscopy (MFM) was used to image the magnetic domain patterns. A Bruker Multimode V Nanoscope 8 microscope equipped with a fully non-magnetic head and scanner, and a commercial Bruker MESP-HR10 cantilever coated with Co/Cr hard magnetic alloy were utilized. The mechanical properties of the films were measured by nanoindentation using a pyramidal-shaped Berkovich-type diamond tip [24]. Indentation experiments were performed in raster across the sample surface and the values for the reduced Young’s modulus, Er, and the Berkovich hardness, HB, were determined as the average from ≈ 300 indentations for each film using the method of Oliver and Pharr [25]. A complete list of the samples synthesized both via electrodeposition and via sputtering and analyzed in this work is reported in Table 1.