Ni - MH batteries have superior properties which are long cycle life, low maintenance, high power, light weight, good thermal performance and configurable design. Hydrogen storage alloys play a dominant role in power service life of a Ni - MH battery and determining the electrochemical properties of the battery. LaNi5, belonging to the CaCu5 crystal structure type, satisfy many of the properties. The most important property of LaNi5 is fast hydrogen kinetics. Recently, CaNi5, belonging to same crystal type, has taken some attention due to its low cost, higher hydrogen storage capacity, good kinetic properties. However, the main restriction of its use is its very low cycle life. The aim of the study is to obtain a more stable structure providing higher cycle life by the addition of different alloying elements. In this study, the effect of sixteen alloying elements (Mn, Sm, Sn, Al, Y, Cu, Si, Zn, Cr, Mg, Fe, Dy, V, Ti, Hf and Er) on cycle life was investigated. Sm, Y, Dy, Ti, Hf and Er were added for replacement of Ca and Mn, Sn, Al, Cu, Si, Zn, Cr, Mg, Fe and V were added for replacement of Ni. Alloys were produced by vacuum casting and heat treating followed by ball milling. The cells assembled, using the produced active materials as anode, which were cycled for charging and discharging. As a result, replacement of Ca with Hf, Ti, Dy and Er, and replacement of Ni with Si and Mn were observed to show better cycle durability rather than pure CaNi5.

Ni-MH battery today is one of the most widely used secondary battery type because of its properties like secure use at high voltages, excellent thermal properties and consisting of environmentally acceptable materials. LaNi5, as an anode material, is the dominant commercial active material for the Ni-MH battery industry. CaNi5, belonging to same crystal structure, is an alternative for LaNi5, due to higher hydrogen storage capacity, higher theoretical discharge capacity, light weight and low cost. However, low cycle life is the main restriction for the use of CaNi5. In this study, effects of alloying was studied using an ab initio pseudo potential method. In this regard, formation energies of the CaNi5 compounds having different alloying elements were calculated for the understanding of the effect of the alloying element on the stability of the compound. It was found that, all lanthanides and actinides and early transition metals (Sc, Y, Zr, Hf) replacing Ca and early transition metals (Sc, Ti, Zr, Hf) plus elements like Al, Si, P, Ge, Zn, Sn and Sb replacing Ni, decrease the formation energy of CaNi5. Lower formation energy, compared to the pure compound, increases the stability which could improve the cyclic durability of CaNi5 to be used as an anode in Ni-MH batteries. In addition, in order to investigate effects of alloying on Ca diffusion in CaNi5, activation energies of Ca diffusion for different alloys were calculated by Nudged Elastic Band method (NEB) method.

L'abaissement de la température de fonctionnement des SOFC vers 600-750°C est un impératif incontournable pour en augmenter la durée de vie et permettre l'utilisation d'interconnecteurs moins onéreux. Cependant, ceci s'accompagne d'une incrémentation de la chute ohmique de l'électrolyte et des surtensions aux électrodes et, par conséquent, la diminution des performances électrochimiques de la pile. Différentes solutions sont à explorer : substituer l'électrolyte, diminuer la résistance de l'électrolyte usuel en réduisant son épaisseur (<5 µm) et, de toute façon, en améliorant les réactions aux interfaces par adjonction de couches minces fonctionnelles. D'une part, cette étude analyse différentes approches d'élaboration de couches minces de CeO2 et de cérine dopée, dont le rôle est avéré, notamment au niveau de l'oxydation à l'anode : le dépôt par couches atomiques, ALD (Atomic Layer Deposition), et le dépôt chimique en solution CBD (Chemical Bath Deposition) ont été explorés. D'autre part, l'exploitation d'un nouveau matériau composite (cérine dopée au gadolinium et Li2CO3-K2CO3 à l'état fondu) est analysée en tant que matériau d'électrolyte pour les SOFC. Finalement, les propriétés électrochimiques de ces électrolytes, combinés à des couches minces de cérine et de cérine dopée préparées par ALD, sont étudiées en particulier en conditions anodiques. Le but global est d'explorer le rôle des couches minces et de nouveaux électrolytes prometteurs, essentiellement dans les conditions anodiques des SOFC.

Chemical modeling has become an important subject of research in applied thermodynamics for designing, developing, optimizing and controlling of different industrial processes. In this work, a new database for successful modeling of solid-aqueous phase equilibria in specific hydrometallurgical processes was developed using the Mixed Solvent Electrolyte (MSE(H3O+)) model of the OLI Systems software. The ionic interaction parameters between dominant species in the solution were determined by fitting available binary and ternary experimental data such as mean activity, heat capacity and solubility data; then they were validated in multi-component systems. Developed model predicted the phase behaviour in ammoniacal solutions containing cobalt, nickel, copper, and zinc in the Copper Boil process. New sets of double-salt solubility data were measured and used for accuracy validation of the model. Using HSC 6.1 software linked with MSE model, the copper boil processes was simulated successfully to provide some practical recommendations for the optimum process operation.

Chemical modeling has become an important subject of research in applied thermodynamics for designing, developing, optimizing and controlling of different industrial processes. In this work, a new database for successful modeling of solid-aqueous phase equilibria in specific hydrometallurgical processes was developed using the Mixed Solvent Electrolyte (MSE(H3O+)) model of the OLI Systems software. The ionic interaction parameters between dominant species in the solution were determined by fitting available binary and ternary experimental data such as mean activity, heat capacity and solubility data; then they were validated in multi-component systems. Developed model predicted the phase behaviour in ammoniacal solutions containing cobalt, nickel, copper, and zinc in the Copper Boil process. New sets of double-salt solubility data were measured and used for accuracy validation of the model. Using HSC 6.1 software linked with MSE model, the copper boil processes was simulated successfully to provide some practical recommendations for the optimum process operation.

A solid oxide fuel cell (SOFC) is an energy conversion device that has the potential to efficiently generate electricity in an environmentally-friendly manner. In general, a SOFC operates between 750&deg;C and 1000&deg;C utilizing hydrogen or hydrocarbons as fuel and air as an oxidant. The three major components comprising a fuel cell are the electrolyte, the cathode, and the anode. At present, the state-of-the-art SOFC is made from a dense yttria-stabilized zirconia (YSZ) electrolyte, a porous lanthanum manganite cathode, and a porous nickel/YSZ composite anode. With the advent of the anode-supported SOFC and the increased interest in using a wider range of fuels, such as those containing sulphur, knowledge of the anode properties is becoming more important. <br /> The properties of the current anodes are limited due to the narrow range of nickel loadings imposed by the minimum nickel content for electrical conductivity and the maximum allowable nickel loading to avoid thermal mismatch with the YSZ electrolyte. In addition, there is little research presented in the literature regarding the use of nickel metal as a starting anode material, rather than the traditional nickel oxide powder, and how porosity may affect the anode properties. <br /> The purpose of this investigation is to determine the influence nickel morphology and porosity distribution have on the processing and properties of tape cast Ni/YSZ composites. Specifically, the sintering characteristics, electrical conductivity, and thermal expansion behaviour of tape cast composites created from YSZ, nickel, nickel oxide (NiO), nickel coated graphite (NiGr), and/or graphite (Gr) powders are investigated. In addition to samples made from 100% YSZ, 100% Ni, and 100% NiO powders, five composite types were created for this investigation: NiO/YSZ, NiO&Gr/YSZ, Ni/YSZ, NiGr/YSZ, and Ni&Gr/YSZ each with nickel loadings varying between 4 vol% Ni of total solids and 77 vol% Ni of total solids. Another set of composites with a fixed nickel loading of 27 vol% Ni and 47 vol% Ni of total solids and varying graphite loadings were also created. <br /> During the burnout stage, the composites made from nickel oxide powder shrink slightly while the composites made from nickel metal expand due to nickel oxidation. Graphite additions below 20 vol% of the green volume do not alter the dimensional changes of the composites during burnout, but graphite loadings greater than 25 vol% of the green volume cause significant expansion in the thickness of the composites. <br /> After sintering, the amount of volumetric sintering shrinkage decreases with higher nickel loadings and is greater for the composites made with nickel oxide compared to the composites made from nickel metal. The porosity generated in the composites containing graphite is slightly higher than the volume of graphite added to the composite and is much greater than the porosity contained in the graphite-free composites. <br /> Dimensional changes of the porous Ni/YSZ and NiO/YSZ composites during both burnout and sintering were analysed based on concepts of constrained sintering of composite powder mixtures. In some cases constrained sintering was evident, while in others, a more simple rule of mixtures behaviour for shrinkage as a function of YSZ content was observed. <br /> When nickel oxide is reduced to nickel metal during the reduction stage there is essentially no change in the composite volume for the composites containing YSZ because the YSZ prevents the composites from shrinking. After reduction the additional porosity generated in the composites is equivalent to the change in volume due to the reduction of nickel oxide to nickel metal. <br /> When measuring the electrical conductivity, each composite type demonstrated classic percolation behaviour. The NiGr/YSZ composites had the lowest percolation threshold, followed by the Ni/YSZ and NiO/YSZ composites. When graphite was added with a nickel coating, the added porosity did not disrupt the nickel percolation network and allowed the nickel to occupy a larger effective volume compared to a composite made with similar sized solid nickel particles. When graphite was added to the composites, the electrical conductivity was reduced and the percolation threshold increased. <br /> Generally, the coefficient of thermal expansion (CTE) for Ni/YSZ composites are expected to follow the rule of mixtures prediction since the elastic properties for nickel and YSZ are similar. However when porosity is distributed unevenly between the YSZ and nickel phases, the CTE prediction will deviate from the rule of mixtures. When cornstarch was added to the NiGr/YSZ composites, the CTE increased as the amount of porosity in the YSZ phase increased. The CTE of the NiGr/YSZ composites followed the rule of mixtures indicating that the porosity was evenly distributed between the nickel and YSZ phases. For the other composite types, the measured CTE was higher than the rule of mixtures prediction suggesting that more porosity was contained within the YSZ phase.

The purpose of the present study was to assess the feasibility of a laser layer manufacturing technique for realization of shape memory alloy (SMA) components with complex geometry. Pre-placed laser solid freeform fabrication (LSFF) was utilized to produce straight and curvaceous SMA parts from a mixture of 55.2 wt%Ni - 44.8 wt%Ti powder. A pulsed Nd:YAG laser was used; while laser pulse width and frequency were held constant at what are considered their optimal values (4 ms and 50 Hz, respectively), laser energy and scanning speeds were varied across samples to determine appropriate values for fabrication of high quality SMA parts . Different pre-placed powder thicknesses were deposited and then mechanically and physically studied. Optical microscopy, SEM, EDS, and XRD methods, as well as microhardness measurements, were used to examine the microstructural characteristics and hardness of the SMA samples. Also, differential scanning calorimetry (DSC) was performed to determine the transformation temperatures of the fabricated parts. The results confirmed the formation of crack-free solid surfaces in which two types of microstructure exist: solid (non-prose) and dendrite arms. EDS chemical composition analysis confirmed the absence of any impurity or oxidise in the cross section of the samples as well as the presence of only nickel and titanium. XRD spectrum analysis indicated the presence of Ni-Ti intermetallic phases, which are almost Ni-Ti but contain a small amount of Ti2Ni. The XRD results also indicated the presence of austenite and martensite phases, which are exchanged during heating or mechanical deformation. The hardness of these samples varied from 250 to 450 HV0.3. Several tests were carried out to investigate the shape memory effect (SME). It was observed that the fabricated SMAs can recover from the bent condition very quickly (i.e., 1 to 8 seconds) depending on their thickness. In general, the fabricated parts were first bent out of their original shapes then heated, in various ways, above the transformation temperature. To theoretically assess the SME performance of the fabricated SMAs with the proposed geometry two models were developed. The first model was established based upon a lump approach in which the part was exposed to an electrical current. The second model, however, was established based upon a finite element method in which a specific domain at one end of the sample was exposed to a source of heat. It was found that the theoretical outputs from both models were in good agreement with the experimental results.

The Bird River sill (BRS) is composed of layered mafic-ultramafic intrusive bodies which intruded the Bird River greenstone belt in southeastern Manitoba. Layered intrusions, such as those that collectively make-up the BRS, are important hosts to base and precious metal deposits. This study was initiated to examine and develop an emplacement model for the western half of the BRS and to establish the controls on Cr-Ni-Cu-PGE mineralization. The BRS intrusions were emplaced through multiple-magmatic injections into different stratigraphic levels in the Lamprey Falls Formation. It is interpreted that the central BRS intrusions are connected and represent a single conduit system. The BRS and the Lamprey Falls Formation are overlain by the metasedimentary rocks of the Peterson Creek Formation and are overturned. The stratigraphy of the BRS is divided into four series which are from the base upwards: 1) marginal mafic series, 2) ultramafic series, 3) transition series, and 4) mafic series. All significant concentrations of Cr-Ni-Cu-PGE are contained in the ultramafic series. Mineralization is magmatic in origin with significant Ni-Cu and PGE remobilization associated with late felsic magmatism. Ni-Cu remobilization is also associated with mineralized shear zones that cross-cut the BRS and Lamprey Falls Formation. The sulphur source could not be determined unambiguously based on sulphur isotopes alone but the δ34S values of the BRS intrusions suggests that the sulphur in the BRS is magmatic in origin and that two of the BRS bodies may have assimilated external sulphur. The findings of this investigation have considerable economic implications. The model that each BRS body is an individual intrusion implies each body may contain its own style of mineralization. Secondly, the Page body of the BRS is interpreted to represent a turbulent magmatic environment and to be the first intrusion to form at the lowest stratigraphic level. The magmas that formed the stratigraphically higher BRS intrusions are believed to have passed through the Page intrusion. Therefore, the Page body is an excellent exploration target as it represents a turbulent environment in which significant amounts of primitive magma have passed through which are two key factors in the formation of Ni-Cu-PGE deposits.

In this thesis the magnetic and structural properties of ultra-thin 3d transition metals films have been investigated, in particular Fe, Ni and Co films. X-ray Magnetic Circular Dichroism (XMCD) has provided element specific spin (ms ) and orbital (ml ) moments per atom by utilizing the magneto optic sum-rules. Element specific hysteresis curves have been measured by means of X-ray Resonant Magnetic Scattering (XRMS), and the local crystallographic structure has been investigated using Extended X-ray Absorption Fine Structure (EXAFS). By performing XMCD on Fe/Ag(100) we observe a spin reorientation from in-plane to out-of-plane as the Fe thickness is lowered. At temperatures below 300K it occurs around 5-7 mono layers (ML) of Fe. While reorienting the magnetization out-of-plane the orbital moment increases with 125% but only a minor increase (5%) of the spin moment is observed. Extended X-ray Absorption Fine Structure (EXAFS) measurements indicate that films 6 ML and thicker have a bulk-like bcc structure. For the thin out-of-plane films, the local crystallographic structure is more complicated. The spin reorientation of the Au/Co/Au tri-layer system has been studied as a function of temperature, Co layer and Au cap thickness. An unexpected behavior of the orbital moment upon spin reorientation is found in these systems. An ex-situ prepared sample shows a smooth spin reorientation from an in-plane to an out-of-plane easy magnetization direction as the temperature is lowered from 300K to 200K. In-situ prepared samples have also been investigated and a novel phase diagram has been identified. The Au/Co interface has been explored during the Au capping by means of photoemission measurements. In the bi- and tri-layer system of Fe and Ni we have been able to manipulate the spin reorientation by varying the Fe and Ni thickness. A novel non-collinear interlayer exchange interaction for 3d ferro magnets in direct contact has been discovered for a set of samples. This exchange interaction is found to be strongly dependant on the preparation conditions.

The task of this project was to build an computer processing system for pressureregulation, in which the pressure loss over the open hydrolicvalve should be kept as low as possible. By using an cross connected proportional directional valve the valve problem could be solved. The control- and regulationproblem for the pressureregulation system was solved by using the DAQ- card NI6035E from National Instruments and the computerprogram Automatic Pressure Control 1.0 which has been software developed and written in Visual Basic. The final result showed that correct processvarible was obtained in 0,5 seconds, when the setpoint was changed in the testarea 0 - 2,5 MPa. / Uppgiften för examensarbetet har varit att bygga ett processdatorsystem för tryckreglering, där tryckfallet över öppen hydraulventil skall hållas så lågt som möjligt. Med hjälp av en korskopplad proportionalriktningsventil kunde uppgiftens ventilproblem lösas. Styr- och reglerproblemet för tryckreglersystemet löstes med mätkortet NI-6035E från National Instruments och datorprogram- met Automatic Pressure Control 1.0 som mjukvaruutvecklades och skrevs i Visual Basic. Det slut- giltiga resultatet gav att korrekta ärvärden erhölls efter 0,5 sekunder, när börvärdet förändrades inom testområdet 0 - 2,5 MPa.