Neste trabalho foi estudado as ligas La0,7-xMgx Pr0,3Al0,3Mn0,4Co0,5Ni3,8 (x = 0 a 0,7) como eletrodo negativo de baterias de níquel - hidreto metálico. A hidrogenação das ligas foi realizada com duas pressões de H2 (2 bar e 10 bar) e temperaturas (ambiente e 500°C). A capacidade de descarga das ba terias de níquel hidreto metálico foram analisadas pelo equipamento de testes elétricos ARBIN BT-4. As ligas, no estado bruto de fusão, foram analisadas por microscopia eletrônica de varredura (MEV), espectroscopia de energia dispersiva (EDS) e difração de Raios-X. Com o aumento da concentração de Mg nas ligas aumenta-se a capacidade de descarga, porém nota-se a diminuição a estabilidade cíclica das baterias. A capacidade de descarga máxima obtida foi para a liga Mg0,7Pr0,3Al0,3Mn0,4Co0,5Ni3,8 (60 mAh) e a bateria que apresentou a melhor performance foi La0,4Mg0,3Pr0,3Al0,3Mn0,4Co0,5Ni3,8 (53 mAh e 150 ciclos). A capacidade de absorção de hidrogênio diminui quando se adiciona Mg, não ocorrendo tal efeito para a liga Mg0,7Pr0,3Al0,3Mn0,4Co0,5Ni3,8. / In this work were studied of La0.7-xMgx Pr0.3Al0.3Mn0.4Co0.5Ni3.8 (x = 0 and 0.7) alloys for negative electrodes of the nickel-metal hydride batteries. The hydrogenation of the alloys was performed varying pressing of H2 (2 and 10 bar) and temperature (room and 500°C). The discharge capacity of the nic kel-metal hydride batteries were analyzed in ARBIN BT- 4 electrical test equipment. The as-cast alloys were analyzed by scanning electron microscopy (SEM), energy disperse spectroscopy (EDX) and X-Ray diffraction. The increasing Mg addition in the alloy increases maximum discharge capacity but decrease cycle life of the batteries. The maximum discharge capacity was obtained with the Mg0.7Pr0.3Al0.3Mn0.4Co0.5Ni3.8 alloy (60 mAh) and the battery which presented the best performance was La0.4Mg0.3Pr0.3Al0.3Mn0.4Co0.5Ni3.8 alloy (53 mAh and 150 cycles). The H2 capability of absorption was diminished for increased Mg addition and no such effect occurs for Mg0.7Pr0.3Al0.3Mn0.4Co0.5Ni3.8 alloy.

Foram feitos estudos das propriedades magnéticas e estruturais em nanofios de níquel em uma lâmina de alumínio. As amostras foram obtidas através da anodização em duas etapas, seguida de uma eletrodeposição AC. Foi verificado que o aumento do potencial usado nas anodizações acarretam em um aumento do tamanho dos grãos cristalinos de níquel e dos diâmetros dos nanofios. O tamanho dos grãos de níquel e dos diâmetros dos nanofios variaram, respectivamente, entre 10 a 20 nm e 30 a 50 nm. As amostras apresentam alta anisotropia de forma, com coercividade entre 565 a 725 Oe. As interações magnéticas foram estudadas através das curvas `delta´M, estas mostraram que as interações desmagnetizantes são dominantes nestes sistemas. O modelo de Stoner-Wohlfarth, acréscido de um termo de interação foi utilizado para simular e interpretar o comportamento magnético dos nanofios. Através dos resultados numéricos e experimentais foi verificado que a componente reversível (Mrev) da magnetização independe do estado inicial do sistema, diferentemente do comportamento para a componente irreversível (Mirr). Através da análise das curvas de Mrev(Mirr)Hi , provenientes dos resultados numéricos e experimentais, foi verificado que existe um forte indicativo quanto ao modo de inversão da magnetização por curling, para nanofios / Studies of magnetic and structural properties of nickel nanowires deposited on nanoporous alumina membranes were carried out. The samples were obtained by a two-step anodization, followed by an AC electrodeposition. It was noted that the diameters of the nanowires and the crystalline grain size of the deposited nickel increase with the anodization voltage. The mean diameters and the grain sizes varied from 10 to 20 nm and from 30 to 50 nm, respectively. The samples exhibited a strong shape anisotropy, with coercivities between 565 and 725 Oe. Magnetic interactions were studied via `delta´M curves, which showed that the dominant interactions are rather demagnetizing in these systems. An interacting Stoner-Wohlfarth model was developed to simulate and reproduce the magnetic behavior of the nanowires. From the comparison between numerical and experimental results (which exhibit excellent agreement), it was noted that reversible components of magnetization (Mrev) do not depend on the initial state of the system, whereas irreversible components (Mirr) do. From the analysis of Mrev(Mirr)Hi curves of numerical and experimental results, it was noted that there is strong evidence for the curling magnetization reversal mode for these systems

Neste trabalho foi feito um estudo das propriedades estruturais e eletroquímicas de eletrodos formados por pó de liga de hidreto metálico Zr0,9Ti0,1Ni1,04Mn0,64V0,46 (tipo AB2) preparadas em forno a arco e tratadas por moagem em moinho de bolas na presença de pó de Ni ou da liga LaNi4,7Sn0,3. Também foram estudadas ligas à base de Mg-Ni preparadas por moagem de alta energia, com e sem a inclusão de um terceiro elemento (Ti ou Pt). Neste último caso, foi realizada deposição eletroquímica para o revestimento da superfície da liga Mg-Ni com paládio. Os estudos nos dois sistemas foram conduzidos utilizando-se as técnicas de EDX (energia dispersiva de raios X), DRX (difração de raios X) e MEV (microscopia eletrônica de varredura) para a caracterização física dos materiais. Também foram realizados experimentos espectroscopia de absorção de raios X (XAS) e de microscopia eletrônica de transmissão (MET). Os estudos eletroquímicos incluíram medidas da polarização dos eletrodos ao longo dos ciclos de carga/descarga, com o monitoramento da capacidade de descarga em função do número de ciclos. Medidas de espectroscopia de impedância eletroquímica em diferentes estado de carga, temperaturas e números de ciclos foram realizadas nos eletrodos formados com as diferentes ligas. Foi observado que a capacidade de armazenamento de carga da liga AB2 sem tratamento, aumenta muito lentamente com o decorrer do número de ciclos de carga/descarga, enquanto que os eletrodos formados com essa mesma liga, porém submetida aos tratamentos superficiais pela moagem com os diferentes aditivos, apresentam ativação muito mais rápida. Pelas medidas de impedância eletroquímica, observou-se alta similaridade da cinética reacional nas várias amostras AB2 analisadas. A substituição parcial da liga MgNi pela Pt levou à uma maior estabilidade aos ciclos de carga e descarga, inibindo a formação de hidróxido de Mg e proporcionando uma cinética tanto de absorção quanto de dessorção do hidreto maior que sua correspondente liga base. A eletrodeposição de Pd nestas ligas, leva à um incremento adicional na estabilidade do eletrodo. / This work reports results of studies on the structure and electrochemical properties of hydrogen storage alloy electrodes, formed by Zr0,9Ti0,1Ni1,04Mn0,64V0,46 (AB2-type), prepared in arc furnace and processed by ball milling in the presence of Ni and/or LaNi4,7Sn0,3 powder additives. The Mg- Ni based alloys with and without incorporation of Ti and Pt, processed by mechanical alloying were also investigated. In this case, electrochemical deposition of palladium was carried out on the surface of Mg-Ni based alloy particles aiming at improving the alloy stability. The structure of all materials were characterized by energy dispersive X-ray (EDS) analyses, X-ray diffraction (XRD) and scanning electronic microscopy (SEM). X-ray absorption spectroscopy (XAS) and transmission electron microscopy (TEM) were also employed for this purpose. Electrochemical studies involved measurements of the electrode polarization along the charge/discharge cycles and also monitoring total discharge capacity as a function of the cycle number. Reaction kinetics were investigated by electrochemical impedance spectroscopy (EIS) measurements, conducted at different states of charge, temperatures and cycle numbers for the different metal hydride electrodes. It was found that the charge storage capacity increased very slowly along the initial charge/discharge cycles for the bare AB2 alloy, but a significant decrease of the activation time, due to a raise on the active area caused by the milling treatment was seen, independent of the additive nature. Electrochemical impedance showed similar reaction kinetics for different AB2 samples. The inclusion of small content of Pt in the Mg-Ni alloy leaded to a significant increase of the material stability for the charge/discharge cycles, probably because of a reduction in the corrosion processes. Consistently, the electrochemical coatings of Pd lead to a raise in the cycling stability of these alloys.

Neste trabalho, investigou-se a atividade catalítica de materiais a base de Ni/YSZ modificados com Rh ou Ru a 0,5%, 1% e 3%, para a reforma a vapor de etanol (RVE) e seus desempenhos como eletrocatalisadores em células a combustível de óxido sólido (SOFCs - Solid Oxide Fuel Cell). Os catalisadores foram preparados pelo método Pechini e de impregnação. A caracterização estrutural foi realizada utilizando-se as técnicas de Energia Dispersiva de Raios X, Difratometria de Raios X, Redução à Temperatura Programada, Fisissorção de Nitrogênio, Microscopia Eletrônica de Varredura e Análise Elementar. Os testes catalíticos foram realizados a 700 e 900 °C, em uma linha de reação acoplada a um cromatógrafo a gás para o monitoramento dos produtos reacionais gasosos. Os produtos líquidos resultantes da RVE foram analisados por Cromatografia Líquida de Alta Eficiência (CLAE). O objetivo principal foi correlacionar a estrutura e a composição destes materiais com a produção de H2, distribuição de outros produtos reacionais e formação de depósitos de carbono. Os resultados obtidos mostraram que a incorporação de Rh ou Ru no catalisador de Ni/YSZ não resultou em mudanças significativas na estrutura e atividade catalítica, porém promoveu uma diminuição na quantidade de carbono formado, sendo mais expressiva para o caso da adição de Rh. O aumento da temperatura de reação de 700 °C para 900 °C resultou em um aumento da seletividade dos catalisadores para os produtos gasosos e diminuição da formação de coque. O estudo em uma célula unitária de SOFC foi conduzido utilizando-se platina no cátodo e 3%Rh/40%Ni/YSZ(P) no ânodo, em uma célula operando com H2 e ar a 900 °C. Embora as curvas de polarização tenham apresentado baixas densidades de potência, os resultados mostraram que o material de 3%Rh/40%Ni/YSZ(P) foi ativo para a produção e eletro-oxidação de H2 em condições reais de operação das SOFCs. Além disso, mostrou-se que é possível investigar a atividade de eletrocatalisadores de ânodos de SOFC para a reforma de etanol em linhas de reação comumente utilizadas em estudos de catálise heterogênea. / In this work, it was investigated the electrocatalytic activity of Ni/YSZ promoted with Rh or Ru (0.5 wt%, 1.0 wt% and 3.0 wt% content) for the Ethanol Steam Reforming (ESR) reaction, and their performance as electrocatalysts in Solid Oxide Fuel Cells (SOFCs). The catalysts were prepared by the Pechini and Impregnation methods. The material characterization was carried out by Energy Dispersive X-ray (EDX), X-ray Diffraction (DRX), Temperature Programmed Reduction (TPR-H2), N2 physisorption, Scanning Electron Microscopy (SEM), and Elemental Analysis. The catalytic tests were performed at 700 and 900 °C in a reaction system coupled to a gas chromatograph in order to monitor the gaseous products. The liquid products were analyzed by High Performance Liquid Chromatography (HPLC). The structure and composition of these catalysts were correlated to the H2 formation, with the distribution of other parallel reaction products, including the carbon deposition. The obtained results showed that the incorporation of Rh or Ru does not change significantly the structure and catalytic activity, but it decreases the carbon deposits, being more significant for the addition of Rh. The increase of the reaction temperature from 700 °C to 900 °C increased the gaseous products selectivities and decreased the carbon deposition. The study in SOFC unit cells were conducted using platinum and 3%Rh/40%Ni/YSZ(P) in the cathode and anode, respectively. The SOFC operated with H2 and air, and 900 °C. Although the polarization curves have presented low power densities, the obtained results showed that the 3%Rh/40%Ni/YSZ(P) electrocatalyst was active for the H2 production and eletro-oxidation in the SOFC real operation conditions. Furthermore, the results have demonstrated that it is possible to investigate SOFC electrocatalysts activity for the ethanol steam reforming in reaction lines commonly utilized in heterogeneous catalysis studies.

Ni-Co-Mn-In system is a new type of magnetic shape memory alloys (MSMAs) where the first order structural and magnetic phase transitions overlap. These materials can generate large reversible shape changes due to magnetic-field-induced martensitic transformation, and exhibit magneto-caloric effect and magnetoresistance. Ni-Co-Mn-Sn alloys are inexpensive alternatives of the Ni-Co-Mn-In alloys. In both materials, austenite has higher magnetization levels than martensite. Fe-Mn-Ga is another MSMA system, however, whose magnetization trend is opposite to those of the Ni-Co-Mn-X (In-Sn) systems upon phase transformation. The MSMAs have attracted great interest in recent years, and their magnetic and thermo-mechanical properties need to be further investigated. In the present study, the effects of indium concentration, cooling, and annealing on martensitic transformation and magnetic response of single crystalline Ni-Co-Mn-In alloys were investigated. Increasing indium content reduced the martensitic transformation start (Ms) temperature, while increasing temperature hysteresis and saturation magnetization. Increasing annealing temperature led to an increase in the Ms temperature whereas annealing at 400 degrees C and 500 degrees C led to the kinetic arrest of austenite. Cooling after solution heat treatment also notably affected the transformation temperatures and magnetization response. While the transformation temperatures increased in the oil quenched samples compared to those in the water quenched samples, these temperatures decreased in furnace cooled samples due to the kinetic arrest. The possible reasons for the kinetic arrest are: atomic order changes, or precipitate formation. Shape memory and superelastic response, and magnetic field-induced shape recovery behavior of sintered Ni43Co7Mn39Sn11 polycrystalline alloys were also examined. The microstructural analysis showed the existence of small pores, which seem to increase the damage tolerance of the sintered polycrystalline samples. The recoverable transformation strain, irrecoverable strain and transformation temperature hysteresis increased with stress upon cooling under stress. Moreover, magnetic-field-induced strain due to the field-induced phase transformation was confirmed to be 0.6% at 319K. Almost perfect superelastic response was obtained at 343K. A magnetic entropy change of 22 J kg-1 K-1 were determined at 219K from magneto-caloric effect measurements which were conducted on annealed Ni43Co7Mn39Sn11 ribbons. Magnetic characteristics and martensitic transformation behavior of polycrystalline Fe-Mn-Ga alloys were also examined. Cast alloys at various compositions were undergone homogenization heat treatments. It was verified by magnetization measurements that the alloys heat treated at 1050 degrees C shows martensitic transformation. The heat treatment time was determined to be 1 day or 1 week depending on the compositions.

La tesis realizada se engloba dentro de los sistemas de carga rápida de baterías de media y gran capacidad. Dentro de esta tesis se ha desarrollado una metodología de ensayos original para el estudio de los procesos de carga de baterías de Ni-Cd y de Ni-MH. Además se ha propuesto un método de finalización de carga rápida original. El contenido de la tesis es el que se describe a continuación:En el capítulo 1 se estudia el estado del arte relacionado con las distintas tecnologías de baterías utilizadas en sistemas que funcionan bajo regímenes cíclicos de carga-descarga (plomo-ácido, níquel-cadmio, níquel-hidruro metálico y litio-ión). Además, se seleccionan las tecnologías más adecuadas para el funcionamiento en regímenes cíclicos de carga-descarga (Ni-Cd y Ni-MH), se plantea la problemática de la carga rápida y se establecen los objetivos del trabajo.En el capítulo 2 se realiza el estudio de las características de descarga de las tecnologías de baterías seleccionadas (Ni-Cd y Ni-MH).En el capítulo 3 se presenta una metodología de ensayos original desarrollada específicamente para el estudio de los procesos de carga en baterías de Ni-Cd y Ni-MH de media y gran capacidad (carga lenta y carga rápida). Además, se presentan los bancos de ensayos desarrollados para la realización de los ensayos de carga.En el capítulo 4 se realiza un exhaustivo análisis de los procesos de carga en baterías de Ni-Cd y Ni-MH basándose en diferentes índices de comportamiento como son: evolución de la tensión y de la temperatura, capacidad cargada y descargada, aceptación de carga, eficiencia energética, etc. Este estudio aporta una valiosa información dada la novedad de las baterías en estudio.En el capítulo 5 se realiza un análisis crítico de los métodos de carga actuales desde el punto de vista de su posible aplicación en carga rápida en baterías de media y gran capacidad.En el capítulo 6 se propone un método original de finalización de carga que junto a la selección de la razón de carga óptima en cada tecnología dan lugar a un método de carga preciso, fiable, fácil de implementar y económico.En el capítulo 7 se resumen las principales conclusiones y aportaciones de la tesis y las líneas futuras de trabajo.

Μελετήθηκε η αντίδραση αναμόρφωσης της αιθανόλης με ατμό προς παραγωγή υδρογόνου για την τροφοδοσία στοιχείων καυσίμου. Η παραγωγή υδρογόνου από αιθανόλη, αποτελεί ελκυστική διεργασία τόσο από οικονομική, όσο και από περιβαλλοντική άποψη. Το παραγόμενο υδρογόνο μπορεί να χρησιμοποιηθεί σε στοιχεία καυσίμου ως ρεύμα τροφοδοσίας, όπου οξειδώνεται ηλεκτροχημικά παρουσία αέρα αποδίδοντας ηλεκτρική ενέργεια και θερμότητα με μοναδικό προϊόν καύσης το νερό. Η αντίδραση αναμόρφωσης της αιθανόλης με ατμό είναι θερμοδυναμικά εφικτή και η αύξηση της θερμοκρασίας οδηγεί σε αυξημένη απόδοση σε υδρογόνο. Η συνολική διεργασία παραγωγής υδρογόνου από ατμοαναμόρφωση της αιθανόλης έχει υψηλότερη θεωρητική απόδοση από την ατμοαναμόρφωση του μεθανίου, η οποία είναι η κύρια διεργασία παραγωγής υδρογόνου σήμερα. Οι μελέτες της αντίδρασης αναμόρφωσης της αιθανόλης με ατμό σε καταλύτες κοβαλτίου, ευγενών μετάλλων και νικελίου, έδειξαν ότι οι βέλτιστοι καταλύτες της διεργασίας είναι οι 2% Rh/Al2O3, 5% Ru/Al2O3 και 17% Ni/(La2O3/Al2O3). Οι καταλύτες νικελίου εναποτεθειμένοι σε γ-Al2O3, La2O3 και La2O3/Al2O3 μελετήθηκαν προκειμένου να διερευνηθεί το δίκτυο των αντιδράσεων της αιθανόλης με τον ατμό με χρήση δυναμικών τεχνικών και τεχνικών μόνιμης κατάστασης. Προσεγγίστηκε το δίκτυο αντιδράσεων και τιτλοδοτήθηκε ο εναποτεθειμένος άνθρακας. Αναπτύχθηκαν κεραμικοί και μεταλλικοί θερμικά ολοκληρωμένοι αντιδραστήρες αναμόρφωσης της αιθανόλης με ατμό. Η πραγματοποίηση των αντιδράσεων αναμόρφωσης και καύσης στον κεραμικό αντιδραστήρα οδήγησε σε ικανοποιητική απόδοση. Παράλληλα, διεξήχθησαν πειράματα αναμόρφωσης και καύσης της αιθανόλης στο μεταλλικό αντιδραστήρα με χρήση καταλυτικών κλινών. Τα πειράματα αναμόρφωσης - καύσης απέδειξαν τη λειτουργικότητα του συστήματος, ενώ η σχετική θέση των καταλυτικών κλινών διαπιστώθηκε ότι αποτελεί σημαντικό παράγοντα στην απόδοση του αντιδραστήρα. Τέλος, αναπτύχθηκαν καινοτόμοι μέθοδοι εναπόθεσης καταλυτικών στρωμάτων στις επιφάνειες μεταλλικών σωλήνων. Στην εξωτερική επιφάνεια εναποτέθηκε αλούμινα ως υπόστρωμα για τον καταλύτη αναμόρφωσης με ψεκασμό πλάσματος, ενώ στο εσωτερικό του σωλήνα χρησιμοποιήθηκε μέθοδος εναπόθεσης αλουμινίου για τη δημιουργία του απαιτούμενου συγκολλητικού υποστρώματος. Οι καταλύτες που παρήχθησαν είχαν υψηλή αντοχή σε θερμικούς κύκλους και μεγάλη απόδοση στην αντίδραση αναμόρφωσης. / Production of hydrogen from steam reforming of ethanol is examined for application in fuel cells. The production of hydrogen from ethanol is an attractive operation from economical as well as from environmental point of view. The produced hydrogen can be fed to fuel cells, undergoing oxidation and producing electric energy and heat with the only combustion product being water. Steam reforming of ethanol is thermodynamically feasible and high temperatures result in high efficiency towards hydrogen production. The overall thermal efficiency of the operation is calculated and proven to be higher than the respective value of steam reforming of methane, which is the main commercial hydrogen producing operation. Steam reforming of ethanol was studied with catalysts based on Co, noble metals and Ni. The most promising materials were found to be the 2% Rh/Al2O3, 5% Ru/Al2O3 and 17% Ni/(La2O3/Al2O3) catalysts. The reaction network of steam reforming of ethanol, as well as carbon deposition, over nickel catalysts supported on γ-Αl2O3, La2O3 and La2O3/γ-Al2O3 is investigated employing transient and steady state techniques. Ceramic and metallic heat integrated reactors were developed for the reaction of steam reforming of ethanol. Experiments of coupled combustion – reformation in the ceramic reactor resulted in increased efficiency. In addition, experiments of coupled combustion – reformation were carried out in a metallic reactor by use of catalytic beds. The combustion-reformation experiments proved the effectiveness of the reactor, while the relative position of the two catalytic beds plays important role in the efficiency of the reactor. Finally, novel methods of catalyst deposition over metallic tubes were developed. On the outer surface an intermediate film of aluminum oxide was deposited by means of thermal plasma spraying in order to support the catalyst. Over the inner surface of the tube, aluminum powder was deposited and thermally processed to produce the necessary intermediate substrate. The materials produced by the above mentioned methods, were rigid and stable under extreme thermal-cycles, additionally the reforming material exhibited high efficiency.

No description available.

Introduction Copper-64 is an emerging radionuclide with applications in PET molecular imaging and/or internal therapy and it is typically produced by proton irradiation of isotopically enriched 64Ni electrodeposited on a suitable backing substrate. We recently reported a simple and efficient method for the preparation of nickel targets from electrolytic solutions of nickel chloride and boric acid [1]. Herein we report our recent research work on the analysis of metallic impurities in the copper-fraction of the radiochemical separation process. Material and Methods Nickel targets were prepared and processed as previously reported [1]. Briefly, the bath solution was composed of a mixture of natural NiCl2. 6H2O (135 mg/ml) and H3BO3 (15 mg/ml) and Ni was electrodeposited using a gold disk as cathode and a platinum wire as anode. The plating process was carried out at room temperature using 2 ml of bath solution (pH = 3.7) and a constant current density of 60 mA/cm2 for 1 hour. The unirradiated Ni targets were dissolved in 1–2 ml of concentrated (10M) HCl at 90 oC. After complete dissolution of the Ni layer, water was added to dilute the acid to 6M, and the solution was transferred onto a chromatographic column containing AG 1-X8 resin equilibrated with 6M HCl. The Ni , Co and Cu isotopes were separated by using the well-known chromatography of the chloro-complexes. The sample-fractions containing the Cu isotopes (15 ml, 0.1M HCl) were collected in plastic centrifuge tubes previously soaked in 1M HNO3 and rinsed with Milli-Q water (18 MΩ cm). Impurities of B, Co, Ni, Cu and Zn in these samples were determined by inductively coupled plasma-mass spectroscopy (ICP-MS) at the Department of Geosciences (Laboratory of Isotopic Studies) of the National University. Results and Conclusions The mass of Ni deposited in 1 h was 25.0 ± 1.0 mg (n = 3) and the current efficiency was > 75 % in all cases. The pH of the electrolytic solution tended to decrease along the electrodeposition process (3.71.6). The results of ICP-MS analysis of the Cu-fractions from the cold chromatography separation runs are shown in FIG. 1. We were particularly interested in the boron impurities as H3BO3 is used as buffer for electrodeposition of the Ni targets. Except for the Ni impurities that were deter-mined to be in the range of ppm (mg/l), all other analyzed metallic impurities were found to be in the range of ppb (µg/l), including boron. The Co, Ni, Cu and Zn impurities determined in the Cu-fraction in this work using Ni targets electrode-posited from a NiCl2 acidic solution, are in the same order of magnitude compared with that obtained when using targets prepared from an alkaline solution [2], with the advantage of the simplicity of the electrodeposition method from NiCl2 solutions, as the target material is already recovered in the chemical form of NiCl2, enabling a simpler, one step process to prepare a new plating solution when using enriched 64Ni target material for the production of 64Cu.

Ferromagnetic shape memory alloys FSMAs have diverse application, especially in the aerospace and bio-medical industries. They are a class of active and smart materials exhibiting strains under the influence of an applied magnetic field. These magnetic properties are mainly attributed to the martensitic structural phase trans- formation these material experience in response to temperature variation. Co-Ni-Al based alloys are one of the most promising ferromagnetic shape memory alloy FSMA that has been put recently under extensive study by researchers. They have shown extensive and promising features specifically those related to self-actuation. The effect of valence electron concentration and magnetic properties of Co-Ni-Al based ferromagnetic shape memory alloys on the martensitic transformations were analyzed utilizing Ab-initio first principle calculations. The variations of martensite start temperatures (Ms) and magnetic properties of a number of stoichiometric and mnon-stoichiometric Co-Ni-Al ferromagnetic shape memory alloys (FSMA’s) with B2 austenite structure were studied and analyzed as a function of composition and lattice site ordering and site preference. A major conclusion of this thesis suggests that the magnetic valence number (Zm) should be considered in conjunction to the e/a ratio if the composition profile of the Ms is to be determined. Both Monte-Carlo and Ab-initio simulations were implemented to obtain the magnetic Heisenberg’s exchange coupling parameters (J m) and model the magnetic transformations in stoichiometric Co2NiAl FSMAs. Two different cubic structures, ordered and disordered were compared to their tetragonal distortions martensitic phases and their Curie temperature (TC ) were obtained from the Monte-Carlo magnetic susceptibility temperature profile.