The high pressure and high temperature (HPHT) behavior of Ti1-xAlxN coatings on cutting tool inserts have been of interest for this diploma work. A literature study of HPHT techniques as well as measurement methods has been done. A diamond anvil cell (DAC) would be a good device to achieve high pressure and high temperature conditions on small samples. Another way to obtain these conditions would be a cutting test, which has been performed on a Ti1-xAlxN coated cutting tool insert with x = 0.67. Also a cubic press could be used to apply HPHT on a     Ti1-xAlxN sample or a large volume press on a whole cutting tool insert. To measure hardness on thin coatings a nanoindentor could be used, which have been done on heat-treated Ti0.33Al0.67N and TiN samples. X-ray diffraction (XRD) is a suitable method to measure phase composition of a sample and was performed on the cutting tested insert as well as on an untreated reference insert. Three ways to continue this project have been outlined all starting with more comprehensive cutting tests.

This thesis report is focused on the growth of Pt/Mg multilayers and the studies of the sputter yield amplification effect in these. The main application is to use the multilayers as X-ray mirrors reflecting an X-ray wavelength of 17 Å. This wavelength is important for astronomical applications in general, and solar imaging applications in particular. For periodic X-ray multilayer mirrors only a certain specific wavelength of X-rays can be reflected. What wavelength that is reflected depends on the individual layer thicknesses of the materials that are constituting the multilayer. These thicknesses can be determined using modified Bragg’s law and are approximately a quarter of the wavelength. In order to obtain the exact desired layer thickness of each individual layer it is necessary to understand the growth processes and the effects that are going on during deposition of such multilayer mirrors. It has been shown that when depositing multilayers consisting of one very light and one very heavy material, like e.g. Pt and Mg, the deposition rate of the light element is non-linear with deposition time for thin layers. This is because of backscattered energetic neutrals from the heavy target material, which affects the growing film. Furthermore, a sputter yield amplification is present for thin layers when a light element is grown on top of a heavy element, i.e. for Mg on top of Pt. Dual DC magnetron sputtering has been used to grow the Pt/Mg multilayers, and the influence of the backscattered energetic neutrals and the sputter yield amplification effect has been studied for Ar and Kr sputtering gases at pressures ranging from 3 up to 9 mTorr. The individual layer thicknesses have been obtained from simulations of hard X-ray reflectivity measurements using the IMD program. The number of backscattered energetic neutrals and their energies at the target have been calculated using the TRIM code. Using the results obtained it is now possible to predict and compensate for the non-linear deposition rate of Mg.

Many materials exhibit interesting and novel properties when prepared as thin films. Thin film metal oxides have had an impact on the technological progress of the microelectronics mainly due to their electrical and optical properties. Since the future goes towards the nanometre scale there is an increasing demand for thin film deposition processes that can produce high quality metal oxide films in this scale with high accuracy. This thesis describes atomic layer deposition of Ta2O5, HfO2 and SnO2 thin films and chemical vapour deposition of SnO2 thin films. The films have been deposited by employing metal iodides and oxygen as precursors. All these processes have been characterised with regards to important processing parameters. The films themselves have been characterised by standard thin film analysing techniques such as x-ray diffraction, scanning electron microscopy, atomic force microscopy and transmission electron microscopy. The chemical and physical properties have been coupled to critical deposition parameters. Furthermore, additional data in the form of electrical and gas sensing properties important to future applications in the field of microelectronics have been examined. The results from the investigated processes have shown the power of the metal iodide based atomic layer deposition (ALD) and chemical vapour deposition (CVD) processes in producing high quality metal oxide thin films. Generally no precursor contaminations have been observed. In contrast to metal chloride based processes the metal iodide processes produces films with a higher degree of crystalline quality when it comes to phase purity, roughness and epitaxy. The use of oxygen as oxidising precursor allowed depositions at higher temperatures than normally employed in water based ALD processes and hence a higher growth rate for epitaxial growth was possible.

This thesis summarizes the methods and major findings of Ni-W(P)/ã-Al2O3 nitride cata-lyst synthesis, characterization, hydrotreating activity, kinetic analysis and correlation of the catalysts activities to their synthesis parameters and properties.<p> The range of parameters for catalyst synthesis were W (15-40 wt%), Ni (0-8 wt%), P (0-5 wt%) and nitriding temperature (TN) (500-900 °C). Characterization techniques used included: N2 sorption studies, chemisorption, elemental analysis, temperature programmed studies, x-ray diffraction, scanning electron microscopy, energy dispersive x-ray, infrared spectroscopy, trans-mission electron microscopy and x-ray absorption near edge structure. Hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrodearomatization (HDA) were performed at: tem-perature (340-380 °C), pressure (6.2-9.0 MPa), liquid hourly space velocity (1-3 h-1) and hydro-gen to oil ratio (600 ml/ml, STP).<p> The predominant species on the catalyst surface were Ni3N, W2N and bimetallic Ni2W3N. The bimetallic Ni-W nitride species was more active than the individual activities of the Ni3N and W2N. P increased weak acid sites while nitriding temperature decreased amount of strong acid sites. Low nitriding temperature enhanced dispersion of metal particles. P interacted with Al2O3 which increased the dispersion of metal nitrides on the catalyst surface. HDN activity in-creased with Ni and P loading but decreased with increase in nitriding temperature (optimum conversion; 60 wt%). HDS and HDA activities went through a maximum with increase in the synthesis parameters (optimum conversions; 88. wt% for HDS and 47 wt% for HDA). Increase in W loading led to increase in catalyst activity. The catalysts were stable to deactivation and had the nitride structure conserved during hydrotreating in the presence of hydrogen sulfide.<p> The results showed good correlation between hydrotreating activities (HDS and HDN) and the catalyst nitrogen content, number of exposed active sites, catalyst particle size and BET surface area.<p> HDS and HDN kinetic analyses, using Langmuir-Hinshelwood models, gave activation energies of 66 and 32 kJ/mol, respectively. There were no diffusion limitations in the reaction process. Two active sites were involved in HDS reaction while one site was used for HDN. HDS and HDN activities of the Ni-W(P)/ã-Al2O3 nitride catalysts were comparable to the corre-sponding sulfides.

Le diagramme des phases du C60 continue d'être un sujet de discussion et de controverse, malgré la grande quantité de travaux expérimentaux et théoriques fait au fil des ans. Ceci est principalement dû au manque d'études in situ, a l'existence d'états désordonnés présentant des pics de diffraction très mal résolus et à la coexistence de plusieurs polytypes de faible densité. Ce manuscrit présente une étude systématique in situ des transformations hétérogènes du C60 sous haute pression et haute température dans la gamme 1-10 GPa et 300-1200 K. Afin de discriminer les poly(a)morphes de densité similaire dans des échantillons hétérogènes, nous avons utilisé une combinaison de micro-diffraction et micro-tomographie. Les échantillons ont été synthétisés dans une cellule Paris-Edimbourg et caractérisés à l'aide de diffraction des rayons X in situ en dispersion angulaire. Des images tridimensionnels à haute résolution ont été obtenus sur des échantillons trempés par la méthode de micro-tomographie de diffraction/diffusion. Cette méthode permet l'analyse 3D de l'intensité de diffusion reconstruite à partir de séries de projections 2D. Une telle analyse est non destructive et offre une grande sensibilité (0,1% en volume), une haute résolution spatiale (μm3) et peut être multimodale, fournissant des données quantitatives sur la morphologie, la densité, la composition élémentaire ou la structure des matériaux. En outre, nous décrivons le développement d'un système de micro-tomographie in situ sous haute pression et haute température en utilisant une nouvelle cellule rotative Paris-Edimbourg (RoToPEC), combinée avec le rayonnement synchrotron. La capacité à tourner complètement la chambre de l'échantillon sous charge, surmonte la contrainte d'ouverture angulaire limitée des cellules ordinaires et permet l'acquisition de projections tomographiques pour l'imagerie de plein champ ainsi que pour l'imagerie par micro-diffraction. Cette méthode innovante permet l'étude des matériaux sous conditions extrêmes de pression, température ou stress, et pourra être appliquée dans des domaines variés tels que la physique, la chimie, la science des matériaux ou la géologie. Le potentiel de cette nouvelle technique expérimentale est démontré par l'étude de la polymérisation de C60 sous haute-pression et haute température. Mots-clés: C60, diagramme de phase, diffraction, micro-tomographie, haute pression et haute température

A better understanding of the brine-rock- supercritical CO2 interaction is needed to evaluate the risks of geologic CO2 sequestration. The geochemical effects of brine and supercritical CO2 were examined via laboratory modeling of in situ conditions on two reservoir caprocks in the Black Warrior River Basin, the Pottsville and Parkwood Formations. The clay fraction was extracted and treated at ~ 100 bar and 363 K (90 °C) over periods of up to 70 hours. Supercritical CO2 was introduced as dry ice in a pressurized vessel. Samples were observed using XRD, WD-XRF, AA, SEM, and EDS. Clay fractions contained Fe-chlorite, illite, kaolinite, and quartz. Results show the dissolution of illite, CO2-brine induced cation exchange ok K+, and the dissolution of silicate minerals. Steady-state K/Si ratios in the fluid suggest quartz re-precipitation. These interactions could adversely affect the long-term storativity of the caprock and point to a need for further study.

The thermal formation of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), and naphthalenes (PCNs) is a major problem in waste incineration. Ideally, rather than relying on air cleaning systems and treatment techniques, their formation should be minimized or, if possible eliminated. The work presented in this thesis was conducted to obtain a deeper understanding of the thermal formation of PCDDs, PCDFs, PCBs, and PCNs during incineration using a 5 kW laboratory scale incinerator and two artificial wastes that were designed to reflect regional differences in waste composition. The first part of the thesis focuses on the validation of a recently-developed flue-gas sampling probe with enhanced cooling capabilities. Artifact formation of PCDDs and PCDFs can occur during the sampling of hot flue gases if the cooling is insufficient. The new probe was successfully used to collect samples at 700 °C without biasing the measured POP levels. The thermal formation of PCDDs, PCDFs, PCBs, and PCNs in the post-combustion zone of the incinerator was then studied by collecting flue gas samples at 400 °C, 300 °C, and 200 °C during the incineration of the two artificial wastes. Highly chlorinated POPs were formed in larger quantities when burning the waste with the higher content of metals and chlorine, which suggests that high metal levels in the waste favor the chlorination of less chlorinated POPs or otherwise facilitate the formation of highly chlorinated polyaromatics, possibly via the condensation of highly chlorinated phenols. The concentrations of these pollutants and the abundance of highly chlorinated homologues increased as the flue gas cooled. Fly ash particles play an important role in thermal POP formation by providing essential elements (carbon, chlorine, etc.) and catalytic sites. The chemical and mineralogical properties of fly ash samples were studied by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy/Energy Dispersive X-ray (SEM/EDX), and X-ray photoelectron spectroscopy (XPS) to determine their impact on thermal POP formation. Orthogonal Partial Least Squares (OPLS) modeling was used to identify correlations between the observed POP distributions and the physicochemical data. This investigation provided new insights into the impact of fly ash chemistry on thermal POP formation. In addition, the POP isomer distribution patterns generated during waste combustion were examined. These patterns are used to “fingerprint” mechanisms of POP formation. It was found that wastes containing large quantities of metals and chlorine favored the formation of highly chlorinated homologues including the very toxic 2,3,7,8-congeners. The data suggest that reducing fly ash emissions might increase the SO2 content of the flue gas and thereby suppress the Deacon process and the formation of harmful highly chlorinated aromatic species.

ZnO nanoparticles in the size range 2.5–7 nm have been synthesised by a wet chemical method where ZnO particles were grown in basic zinc acetate solution. The optical band gap increases when the size of the particles decreases. An empirical relation between the optical band gap given from absorption measurements, and particle size given from XRD measurements has been developed and compared to other similar relations found in the literature.    Time resolved UV-Vis spectroscopy has been used to follow the growth of particles in situ in solution. The data show that the growth mechanism not can be described by a simple Oswald ripening approach and nor by an exclusive agglomeration of smaller clusters into larger particles. The growth mechanism is more likely a combination of the proposed reaction themes. The data also reveal that particle formation do not demand a heating step for formation of the commonly assumed initial cluster Zn4O(CH3COO)6.    Steady state fluorescence has been studied as a function of particle size during growth in solution. These measurements confirm what is found in the literature in that the visible fluorescence is shifted to longer wavelengths and loses in intensity as the particles grow. Some picosecond spectroscopy has also been done where the UV fluorescence has been investigated. From these measurements it is apparent that the lifetime of the fluorescence increases with particle size.     The phonon spectrum of ZnO has been studied with Raman spectroscopy for a number of different particle sizes. From these measurements it is clear that there is a strong quenching of the phonons due to confinement for the small particles, and the only clearly observed vibration is one at 436 cm-1 which intensity strongly increases with particle size.

This thesis summarizes the methods and major findings of Ni-W(P)/ã-Al2O3 nitride cata-lyst synthesis, characterization, hydrotreating activity, kinetic analysis and correlation of the catalysts activities to their synthesis parameters and properties.<p> The range of parameters for catalyst synthesis were W (15-40 wt%), Ni (0-8 wt%), P (0-5 wt%) and nitriding temperature (TN) (500-900 °C). Characterization techniques used included: N2 sorption studies, chemisorption, elemental analysis, temperature programmed studies, x-ray diffraction, scanning electron microscopy, energy dispersive x-ray, infrared spectroscopy, trans-mission electron microscopy and x-ray absorption near edge structure. Hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrodearomatization (HDA) were performed at: tem-perature (340-380 °C), pressure (6.2-9.0 MPa), liquid hourly space velocity (1-3 h-1) and hydro-gen to oil ratio (600 ml/ml, STP).<p> The predominant species on the catalyst surface were Ni3N, W2N and bimetallic Ni2W3N. The bimetallic Ni-W nitride species was more active than the individual activities of the Ni3N and W2N. P increased weak acid sites while nitriding temperature decreased amount of strong acid sites. Low nitriding temperature enhanced dispersion of metal particles. P interacted with Al2O3 which increased the dispersion of metal nitrides on the catalyst surface. HDN activity in-creased with Ni and P loading but decreased with increase in nitriding temperature (optimum conversion; 60 wt%). HDS and HDA activities went through a maximum with increase in the synthesis parameters (optimum conversions; 88. wt% for HDS and 47 wt% for HDA). Increase in W loading led to increase in catalyst activity. The catalysts were stable to deactivation and had the nitride structure conserved during hydrotreating in the presence of hydrogen sulfide.<p> The results showed good correlation between hydrotreating activities (HDS and HDN) and the catalyst nitrogen content, number of exposed active sites, catalyst particle size and BET surface area.<p> HDS and HDN kinetic analyses, using Langmuir-Hinshelwood models, gave activation energies of 66 and 32 kJ/mol, respectively. There were no diffusion limitations in the reaction process. Two active sites were involved in HDS reaction while one site was used for HDN. HDS and HDN activities of the Ni-W(P)/ã-Al2O3 nitride catalysts were comparable to the corre-sponding sulfides.

Co-doped ZnO (ZnO:Co) thin film with room temperature ferromagnetism and spin polarized carriers is one of the advance materials and highly applicable in future development in spintronics. When ZnO:Co films deposited by a £_ growth method in a ion sputtering system, low solubility of Co (3.75%) limits further applications such that a single-guns sputtering thin film growth technique is employed in this study to outreach this limitation. A ZnO:Co bulk with 5 at% of Co was formed by a solid reaction method and used as a target. ZnO:Co films were grown in a single-gun RF sputtering system. However, all films grown at room temperature were insulator which might because sufficient oxygen content in the target and the negative charge of oxygen ion moving toward substrate making the films of full oxygen content. In this study, the post annealing in vacuum environment and the deposition of films in hydrogenation environment are conducted to try to produce various level of oxygen vacancies in the films for understanding the interplay between the oxygen vacancies and the electric transport and magnetic coupling. The present experiment contains two parts: (1) grow films with various thicknesses by controlling deposition time and then applying post annealing process, and (2) grow the films in oxygen reduced environment by introducing hydrogen during growth and taking out partial oxygen content in the plasma and the films. In the first part, the grain sizes of the films are near constant while the crystal quality is improved with the thickness of films. The worse crystal quality of grains, the better the electric transport and the stronger the magnetic coupling after post annealing processes. This indicates that the electric transport and magnetic coupling could be improved when the thin films was formed by crystals with certain disordering and contained a certain level of oxygen vacancies. In the second part, the introduced hydrogen may combine with the oxygen sputtered out from the target before deposition on substrates. It means that the films are grown in oxygen deficient conditions and result in various degrees of oxygen vacancies. Zn clusters precipitate in films when the concentration of hydrogen is over 20%, and at the meantime, they increase the conductivity and suppress the magnetic coupling in the films. These discoveries provide new perspective in understand the electric transport and ferromagnetism mechanics in DMS materials.