published_or_final_version / Industrial and Manufacturing Systems Engineering / Master / Master of Philosophy

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In this research, the effects of gas composition, elapsed time of reaction and temperature on scale formation and descaling of low carbon steel were investigated and results were discussed from the viewpoint of the phase composition of the scales, oxidation rates, oxidation mechanisms, adhesion, fracture mechanics, porosity and residual scale. / The phase composition and morphology of scales grown under conditions similar to those of reheating furnaces were analyzed. Low carbon steel was oxidized over the temperature range 1000-1250°C in gas mixtures of O 2-CO2-H2O-N2, O2-H 2O-N2 and O2-CO2-N2. The mole fraction of each phase, wustite (FeO), magnetite (Fe3O 4) and hematite (Fe2O3) was determined by the direct comparison method Two types of scales were observed. The first type was a crystalline scale with an irregular outer surface composed mostly of wustite, and a negligible amount of magnetite. The second type was the classical three-layer scale composed of wustite, magnetite and hematite. In general, the experiments showed that the furnace atmosphere, oxidation time and temperature influence the phase composition of the scales. / Low carbon steel was oxidized in air over the temperature range 600-1200°C for 120 s to approximate the formation of secondary and tertiary scale in hot rolling. The mole fraction of wustite, magnetite and hematite was determined by the direct comparison method The phase composition of the scales changed with temperature and time. During the initial 30 s of oxidation, wustite was the predominant phase in the temperature range 800-1200°C, and as oxidation proceeded, the percentages of magnetite and hematite increased. In addition, the texture of the scales was investigated by orientation imaging microscopy (OIM); it was found that temperature influences the texture of the scales. The experiments indicated that 850°C is the ideal temperature for the finishing mill in order to reduce surface defects and work roll wear. / The adhesion of scales formed in air on low carbon steel in continuous heating and isothermal conditions was investigated with a four-point bending test. The separation (crack) always occurred inside the scale indicating that the strength of the scale is lower than the strength of the scale/steel interface. It was found that scale adhesion is related to scale porosity, blister formation and stresses acting in the scale. A spallation process was observed when cooling from 800°C to room temperature. The microscopic observations revealed that spallation followed route 1 "strong interface and weak oxide." / Low carbon steel was oxidized over the temperature range 1050-1250°C in O2-CO2H2O-N2 gas mixtures in order to study the hydraulic descaling process. The oxidation times were 15-120 min. and the scales were 130-2000 mum thick. The experimental parameters were chosen to approximate scale formation under conditions similar to those of reheating furnaces. In the hydraulic descaling tests, two modes of scale removal were observed. In the first mode, observed in classical three-layer scales that developed an inner porous layer with low or medium porosity, the horizontal undercutting occurred at the boundary of the inner porous layer and dense scale. The second mode was observed in classical three-layer scales that developed an inner porous layer with high porosity and in crystalline scales. In the second mode, the horizontal undercutting occurred at the first plane of large pores relative to the scale/steel interface. In general, the experiments showed that scale morphology controlled the removability of scale.

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Due to continued transistor scaling, work function tuning of metal gates has become important for advanced CMOS applications. Specifically, this research has been undertaken to discover the tuning of the MoxSiyNz gate work function through the incorporation of nitrogen. Metal Oxide Semiconductor (MOS) capacitors were fabricated using thermal SiO2 as gate oxide on lightly doped p-type Si wafer. A molybdenum silicide (MoSi2) target was reactively sputtered at 10mTorr in presence of N2 and Ar. The gas flow ratio, RN = N2/ (N2+Ar), was adjusted to vary the nitrogen concentration in MoSiN films. The gate work function (Фm) was extracted from capacitance-voltage (CV) measurements using the VFB-tox method. Interfacial barrier heights were measured using internal photoemission (IPE) as an independent confirmation of the MoSiN gate work function. The work function was found to decrease linearly (from ~4.7eV to ~4.4eV) for increasing gas flow ratios (from 10% to 40%). Secondary ion mass spectrometry (SIMS) depth profiles suggested that the nitrogen concentration was relatively uniform throughout the film. X-Ray Photoelectron Spectroscopy (XPS) surface analysis showed a steady increase in the total nitrogen concentration (from ~20% to 32%) in these films as gas flow ratio was increased. These data suggests that the increase in nitrogen concentration in MoSiN films corresponds directly with the lowering of MoSiN work function. These results clearly demonstrate that the work function of MoxSiyNz can be varied ~0.3 eV by adjusting the nitrogen concentration.

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This creative project resulted in five metal handbags, each based on a specific period from art history: Egyptian, Classical, Art Nouveau, Art Deco and Memphis. These styles range from early human history to contemporary times and possess very explicit and identifiable motifs. They maintain links to each other and impact design to this day.The project culminates in an exhibit. A brief description of the relevant era is printed on attached tags to generate mini art history lessons. People who see or use the handbags will gain exposure to art history they may not otherwise seek out, potentially piquing their curiosity. The aim is to sell all five handbags so they may demonstrate that art history is a vital part of human history because it continues to inform and inspire a spectrum of endeavors from advertising and fashion to engineering and design. / Department of Art

The primary objective of this creative project was the exploration of Japanese sagemono ensembles and the metal working techniques needed for their creation. Sagemono ensembles are hanging accessories worn by the Japanese men of the 16th through the early 20th centuries. The secondary objective was to design and construct four sagemono ensembles using both traditional Japanese themes and patterns along with more contemporary motifs which emerged from the artist's explorations of the original Japanese ensembles. This body of work required a variety of traditional metalsmithing techniques including: complex sheet constructions, photoetching, copper-plating and forming, inlay, and casting. / Department of Art