Open Access. Powered by Scholars. Published by Universities.®
Materials Science and Engineering Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Mechanical Engineering (58)
- Other Materials Science and Engineering (27)
- Chemical Engineering (23)
- Electrical and Computer Engineering (21)
- Physical Sciences and Mathematics (20)
-
- Manufacturing (18)
- Polymer and Organic Materials (15)
- Metallurgy (13)
- Physics (12)
- Semiconductor and Optical Materials (12)
- Structural Materials (12)
- Nanoscience and Nanotechnology (10)
- Condensed Matter Physics (9)
- Biology and Biomimetic Materials (8)
- Chemistry (8)
- Engineering Science and Materials (8)
- Civil and Environmental Engineering (7)
- Other Mechanical Engineering (7)
- Biomedical Engineering and Bioengineering (6)
- Materials Chemistry (6)
- Other Chemical Engineering (6)
- Power and Energy (6)
- Biomechanical Engineering (5)
- Computer-Aided Engineering and Design (5)
- Aerospace Engineering (4)
- Catalysis and Reaction Engineering (4)
- Ceramic Materials (4)
- Energy Systems (4)
- Institution
- Keyword
-
- Daniel Felix Ritchie School of Engineering and Computer Science (28)
- Mechanical and Materials Engineering (16)
- Additive manufacturing (11)
- Mechanical properties (9)
- Microstructure (8)
-
- Diffusion (7)
- Nanocomposites (7)
- College of Natural Science and Mathematics (6)
- Physics and Astronomy (6)
- Solar cells (6)
- Corrosion (5)
- Interdiffusion (5)
- Molecular dynamics (5)
- Polymer derived ceramics (5)
- TEM (5)
- 3D Printing (4)
- 3D printing (4)
- Aluminum (4)
- Finite element analysis (4)
- Materials (4)
- Molybdenum (4)
- Nanocomposite (4)
- Shape memory alloys (4)
- Simulation (4)
- CIGS (3)
- Carbon nanotube (3)
- Carbon nanotubes (3)
- Cellular structure (3)
- Ceria (3)
- Characterization (3)
Articles 211 - 240 of 267
Full-Text Articles in Materials Science and Engineering
Development And Application Study Of Nanoscale Thin Film Materials And Polymer Nanocomposites, Hui Chen
Development And Application Study Of Nanoscale Thin Film Materials And Polymer Nanocomposites, Hui Chen
Electronic Theses and Dissertations
This dissertation demonstrated that the manipulation of substances at the molecular or nanometer level can lead to the discovery and development of new materials with interesting properties and important applications. Chapter 1 describes the development of a nanoscale molecular thin film material for corrosion protection. By using a self-assembled monolayer film with a thickness of only about 1 nanometer as a linkage, a covalent bonding was achieved between a polyurethane top coating and an aluminum alloy substrate. This covalent bonding between polymer top coating and the aluminum alloy substrate significantly improved the corrosion resistance of the substrate. Chapter 2 and …
Effect Of Composition, Morphology And Semiconducting Properties On The Efficiency Of Cuin1-Xgaxse2-Ysy Thin-Film Solar Cells Pre, Sachin Kulkarni
Effect Of Composition, Morphology And Semiconducting Properties On The Efficiency Of Cuin1-Xgaxse2-Ysy Thin-Film Solar Cells Pre, Sachin Kulkarni
Electronic Theses and Dissertations
A rapid thermal processing (RTP) reactor for the preparation of graded CuIn1-xGaxSe2-ySy (CIGSeS) thin-film solar cells has been designed, assembled and is being used at the Photovoltaic Materials Laboratory of the Florida Solar Energy Center. CIGSeS films having the optimum composition, morphology, and semiconducting properties were prepared using RTP. Initially films having various Cu/(In+Ga) ratios were prepared. In the next step selenium incorporation in these films was optimized, followed by sulfur incorporation in the surface to increase the bandgap at the surface. The compositional gradient of sulfur was fine-tuned so as to increase the conversion efficiency. Materials properties of these …
Application Of Polyelectrolyte Multilayers For Photolithographic Patterning Of Diverse Mammalian Cell Types In Serum Free Medium, Vipra Dhir
Electronic Theses and Dissertations
Integration of living cells with novel microdevices requires the development of innovative technologies for manipulating cells. Chemical surface patterning has been proven as an effective method to control the attachment and growth of diverse cell populations. Patterning polyelectrolyte multilayers through the combination of layer-by-layer self-assembly technique and photolithography offers a simple, versatile and silicon compatible approach that overcomes chemical surface patterning limitations, such as short-term stability and low protein adsorption resistance. In this study, direct photolithographic patterning of PAA/PAAm and PAA/PAH polyelectrolyte multilayers was developed to pattern mammalian neuronal, skeletal and cardiac muscle cells. For all studied cell types, PAA/PAAm …
Effects Of Internal Oxidation On Thermo-Mechanical Properties Of Atmospheric Plasma Sprayed Conicraly Coatings, Travis Patterson
Effects Of Internal Oxidation On Thermo-Mechanical Properties Of Atmospheric Plasma Sprayed Conicraly Coatings, Travis Patterson
Electronic Theses and Dissertations
Thermal barrier coatings (TBC) with MCrAlY (M=Co and/or Ni) bond coats have been widely used in hot sections of gas turbines to protect underlying superalloys from high temperatures, oxidation, and hot corrosion. Deposition of MCrAlY bond coats using atmospheric plasma spray (APS), as oppose to conventionally employed vacuum/low-pressure plasma spray and high velocity oxy-fuel deposition, allows greater flexibility in ability to coat economically and rapidly for parts with complex geometry including internal surfaces. There were three objectives of this study. First, relationships between APS spray parameters and coating microstructure was examined to determine optimum spray parameters to deposit APS CoNiCrAlY …
Quantitative Thickness Mapping In High-Angle Annular Dark-Field (Haadf) Scanning Transmission Electron Microscopy (Stem), Haritha Nukala
Quantitative Thickness Mapping In High-Angle Annular Dark-Field (Haadf) Scanning Transmission Electron Microscopy (Stem), Haritha Nukala
Electronic Theses and Dissertations
Only a few methods are currently available for the measurement of sample thicknesses in Transmission Electron Microscopy (TEM). These methods, Convergent-Beam Electron Diffraction (CBED) and thickness mapping in Energy-Filtered TEM (EFTEM), are either elaborate or complex. In this present work, I have investigated and come up with a simple straight-forward method to measure the local thickness of a TEM sample with the atomic number (Z-contrast) imaging using High-Angle Annular Dark Field (HAADF) Scanning Transmission Electron Microscopy (STEM). HAADF STEM shows atomic number contrast for high scattering angles of the electrons, owing to predominant electron scattering at the potential of the …
Production Of Bulk Ceramic Shapes From Polymer Derived Ceramics, Arnold Hill
Production Of Bulk Ceramic Shapes From Polymer Derived Ceramics, Arnold Hill
Electronic Theses and Dissertations
A method has been developed to produce bulk ceramic components from a class of ceramics known as polymer derived ceramics. In the past polymer derived ceramics have been limited to thin film applications or in the fabrication of MEMS devices. The reason being that when the polymer is into a ceramic, large quantities of gas are generated which produce internal pressure that fractures the ceramic components. The method developed here solves that issue by casting into the polymer a 3 dimensional network of polymer fibers in the form of a foam which, during pyrolysis, burns out and leaves a network …
Laser Enhanced Doping For Silicon Carbide White Light Emitting Diodes, Sachin Bet
Laser Enhanced Doping For Silicon Carbide White Light Emitting Diodes, Sachin Bet
Electronic Theses and Dissertations
This work establishes a solid foundation for the use of indirect band gap semiconductors for light emitting application and presents the work on development of white light emitting diodes (LEDs) in silicon carbide (SiC). Novel laser doping has been utilized to fabricate white light emitting diodes in 6H-SiC (n-type N) and 4H-SiC (p-type Al) wafers. The emission of different colors to ultimately generate white light is tailored on the basis of donor acceptor pair (DAP) recombination mechanism for luminescence. A Q-switched Nd:YAG pulse laser (1064 nm wavelength) was used to carry out the doping experiments. The p and n regions …
Preparation And Characterisation Of Stabilized Nafion/Phosphotungstic Acid Composite Membranes For Proton Exchange Membrane Fuel Cell (Pemfc) Automobile Engines, Rohit Agarwal
Electronic Theses and Dissertations
Membrane durability is one of the limiting factors for proton exchange membrane fuel cell (PEMFC) commercialisation by limiting the lifetime of the membrane via electrochemical / mechanical / thermal degradation. Lower internal humidity in the membrane at high temperature ( > 100 °C) and low relative humidity (25-50 %RH) operating conditions leads to increased resistance, lowering of performance and higher degradation rate. One of the promising candidates is composite proton exchange membranes (CPEMs) which have heteropoly acid (HPA) e.g. Phosphotungstic acid (PTA) doped throughout the Nafion® matrix. HPA is primarily responsible for carrying intrinsic water which reduces the external water dependence. …
Synthesis And Characterization Of Polymer-Derived Porous Sicn Ceramics, Yun Wei
Synthesis And Characterization Of Polymer-Derived Porous Sicn Ceramics, Yun Wei
Electronic Theses and Dissertations
The synthesis and characterization of porous SiCN ceramics produced by the method of polymer-derived ceramics were studied in this work. The polymer-to-ceramic conversion technique is a novel revolution in the methods for fabricating porous materials with controlled morphologies and tailored properties. The porous SiCN ceramics can be successfully prepared from thermal decomposition of polymeric precursors (polysilazane) and the pore former (polyvinyl alcohol (PVA)). The fabrication procedures involved the mixing of the pre-ceramic precursor with appropriate concentration of the PVA, curing, pyrolysis and subsequent PVA removal, leaving pores in the ceramic matrix. The material obtained revealed a homogeneous amorphous microstructure consisting …
Amorphous Phase Formation In Mechanically Alloyed Fe-Based Systems., Satyajeet Sharma
Amorphous Phase Formation In Mechanically Alloyed Fe-Based Systems., Satyajeet Sharma
Electronic Theses and Dissertations
Bulk metallic glasses have interesting combination of physical, chemical, mechanical, and magnetic properties which make them attractive for a variety of applications. Consequently there has been a lot of interest in understanding the structure and properties of these materials. More varied applications can be sought if one understands the reasons for glass formation and the methods to control them. The glass-forming ability (GFA) of alloys can be substantially increased by a proper selection of alloying elements and the chemical composition of the alloy. High GFA will enable in obtaining large section thickness of amorphous alloys. Ability to produce glassy alloys …
Prevention Of Environmentally Induced Degradation In Carbon/Epoxy Composite Material Via Implementation Of A Polymer Based Coati, Bradford Tipton
Prevention Of Environmentally Induced Degradation In Carbon/Epoxy Composite Material Via Implementation Of A Polymer Based Coati, Bradford Tipton
Electronic Theses and Dissertations
As the use of fiber reinforced plastics increases in such industries as aerospace, wind energy, and sporting goods, factors effecting long-term durability, such as environmental exposure, are of increasing interest. The primary objectives of this study were to examine the effects of extensive environmental exposure (specifically UV radiation and moisture) on carbon/epoxy composite laminate structures and to determine the relative effectiveness of polymer-based coatings at mitigating degradation incurred due to such exposure. Carbon/epoxy composite specimens, both coated and uncoated, were subjected to accelerated weathering in which prolonged outdoor exposure was simulated by controlling the radiation wavelength (in the UV region), …
Dimesionality Aspects Of Nano Micro Integrated Metal Oxide Based Early Stage Leak Detection Room Temperature Hydrogen Sensor, Sameer Arun Deshpande
Dimesionality Aspects Of Nano Micro Integrated Metal Oxide Based Early Stage Leak Detection Room Temperature Hydrogen Sensor, Sameer Arun Deshpande
Electronic Theses and Dissertations
Detection of explosive gas leaks such as hydrogen (H2) becomes key element in the wake of counter-terrorism threats, introduction of hydrogen powered vehicles and use of hydrogen as a fuel for space explorations. In recent years, a significant interest has developed on metal oxide nanostructured sensors for the detection of hydrogen gas. Gas sensors properties such as sensitivity, selectivity and response time can be enhanced by tailoring the size, the shape, the structure and the surface of the nanostructures. Sensor properties (sensitivity, selectivity and response time) are largely modulated by operating temperature of the device. Issues like instability of nanostructures …
Mechanisms Of Lifetime Improvement In Thermal Barrier Coatings With Hf And/Or Y Modification Of Cmsx-4 Superalloy Substrates, Jing Liu
Electronic Theses and Dissertations
In modern turbine engines for propulsion and energy generation, thermal barrier coating (TBCs) protect hot-section blades and vanes, and play a critical role in enhancing reliability, durability and operation efficiency. In this study, thermal cyclic lifetime and microstructural degradation of electron beam physical vapor deposited (EB-PVD) Yttria Stabilized Zirconia (YSZ) with (Ni,Pt)Al bond coat and Hf- and/or Y- modified CMSX-4 superalloy substrates were examined. Thermal cyclic lifetime of TBCs was measured using a furnace thermal cycle test that consisted of 10-minute heat-up, 50-minute dwell at 1135C, and 10-minute forced-air-quench. TBC lifetime was observed to improve from 600 cycles to over …
Processing And Study Of Carbon Nanotube / Polymer Nanocomposites And Polymer Electrolyte Materials, Muthuraman Harish
Processing And Study Of Carbon Nanotube / Polymer Nanocomposites And Polymer Electrolyte Materials, Muthuraman Harish
Electronic Theses and Dissertations
The first part of the study deals with the preparation of carbon nanotube/polymer nanocomposite materials. The dispersion of multi-walled carbon nanotubes (MWNTs) using trifluoroacetic acid (TFA) as a co-solvent and its subsequent use in polymer nanocomposite fabrication is reported. The use of carbon nanotube/ polymer nanocomposite system for the fabrication of organic solar cells is also studied. TFA is a strong but volatile acid which is miscible with many commonly used organic solvents. Our study demonstrates that MWNTs can be effectively purified and readily dispersed in a range of organic solvents including dimethyl formamide (DMF), tetrahydrofuran (THF), and dichloromethane when …
Low Temperature Nitife Shape Memory Alloys: Actuator Engineering And Investigation Of Deformation Mechanisms Using In Situ Neutr, Vinu Krishnan
Low Temperature Nitife Shape Memory Alloys: Actuator Engineering And Investigation Of Deformation Mechanisms Using In Situ Neutr, Vinu Krishnan
Electronic Theses and Dissertations
Shape memory alloys are incorporated as actuator elements due to their inherent ability to sense a change in temperature and actuate against external loads by undergoing a shape change as a result of a temperature-induced phase transformation. The cubic so-called austenite to the trigonal so-called R-phase transformation in NiTiFe shape memory alloys offers a practical temperature range for actuator operation at low temperatures, as it exhibits a narrow temperature-hysteresis with a desirable fatigue response. Overall, this work is an investigation of selected science and engineering aspects of low temperature NiTiFe shape memory alloys. The scientific study was performed using in …
Vacancy Engineered Doped And Undoped Nanocrystalline Rare Earth Oxide Particles For High Temperature Oxidation Resistant Coating, Ranjith Thanneeru
Vacancy Engineered Doped And Undoped Nanocrystalline Rare Earth Oxide Particles For High Temperature Oxidation Resistant Coating, Ranjith Thanneeru
Electronic Theses and Dissertations
Rare earth oxides with trivalent lattice dopants have been of great interest to researchers in the recent years due to its potential applications in catalysis and high temperature protective coatings. The ability to store oxygen in rare earths is the basis for catalysis because of the ability to change valence states which causes the presence of intrinsic oxygen vacancies in the crystal lattice. Although, several doped-rare earth oxide systems in micron scale have been investigated, the doping effect in cerium oxide nanoparticles with well characterized particle size has not been studied. The doping of ceria at that small size can …
Understanding The Low Temperature Electrical Propertiesof Nanocrystalline Sno2 For Gas Sensor Applications, Christina Drake
Understanding The Low Temperature Electrical Propertiesof Nanocrystalline Sno2 For Gas Sensor Applications, Christina Drake
Electronic Theses and Dissertations
Nanocrystalline metal/metal oxide is an important class of transparent and electronic materials due to its potential use in many applications, including gas sensors. At the nanoscale, many of the phenomena observed that give nanocrystalline semiconducting oxide enhanced performance as a gas sensor material over other conventional engineering materials is still poorly understood. This study is aimed at understanding the low temperature electrical and chemical properties of nanocrystalline SnO2 that makes it suitable for room temperature gas detectors. Studies were carried out in order to understand how various synthesis methods affect the surfaces on the nano-oxides, interactions of a target gas …
Plasma Processing For Retention Of Nanostructures, Viswanathan Venkatachalapathy
Plasma Processing For Retention Of Nanostructures, Viswanathan Venkatachalapathy
Electronic Theses and Dissertations
Plasma spray processing is a technique that is used extensively in thermal barrier coatings on gas and steam turbine components, biomedical implants and automotive components. Many processing parameters are involved to achieve a coating with certain functionality. The coating could be required to function as thermal barrier, wear resistant, corrosion resistant or a high temperature oxidation resistant coating. Various parameters, such as, nozzle and electrode design, powder feeding system, spray distances, substrate temperature and roughness, plasma gas flow rates and others can greatly alter the coating quality and resulting performance. Feedstock (powder or solution precursor) composition and morphology are some …
Tunable Nanostructure Anti-Reflective Coatings, Erik Brinley
Tunable Nanostructure Anti-Reflective Coatings, Erik Brinley
Electronic Theses and Dissertations
Research was conducted on broadband, anti-reflective coatings for fused silica and chalcogenide substrates in the infrared region of light. Using chemical preparation to create nano-porous through nano-particle based sol-gel solutions, the alteration of optical properties including refractive index and optical thickness was conducted. The nano-particles can modify the coating surface to allow only zero-order diffracted wave propagation reducing scattering while a partially graded profile of refractive index due surface evaporation lessened the precise phase relations of typical homogeneous coatings. My study of silica and titania sol-gel, and hybrid mixtures of the two were used to obtain the optical properties of …
Self-Assembled Lipid Tubules: Structures, Mechanical Properties, And Applications., Yue Zhao
Self-Assembled Lipid Tubules: Structures, Mechanical Properties, And Applications., Yue Zhao
Electronic Theses and Dissertations
Self-assembled lipid tubules are particularly attractive for inorganic synthesis and drug delivery because they have hollow cylindrical shapes and relatively rigid mechanical properties. In this thesis work, we have synthesized lipid tubules of 1,2-bis(tricosa-10,12-dinoyl)-sn-glycero-3-phosphocholine (DC8,9PC) by self-assembly and polymerization in solutions. We demonstrate for the first time that both uniform and modulated molecular tilt orderings exist in the tubule walls, which have been predicted by current theories, and therefore provide valuable supporting evidences for self-assembly mechanisms of chiral molecules. Two novel methods are developed for studying the axial and radial deformations of DC8,9PC lipid tubules. Mechanical properties of DC8,9PC tubules …
Zinc Cadmium Sulphide And Zinc Sulphide As Alternative Heterojunction Partners For Cigs2 Solar Cells, Bhaskar Kumar
Zinc Cadmium Sulphide And Zinc Sulphide As Alternative Heterojunction Partners For Cigs2 Solar Cells, Bhaskar Kumar
Electronic Theses and Dissertations
Devices with ZnCdS/ZnS heterojunction partner layer have shown better blue photon response due to higher band gap of these compounds as compared to devices with CdS heterojunction partner layer. CdS heterojunction partner layer has shown high photovoltaic conversion efficiencies with CIGS absorber layer while efficiencies are lower with CuIn1-xGaxS2 (CIGS2). A negative conduction band offset has been observed for CdS/CIGS2 as compared to near flat conduction band alignment in case of CdS/CIGS devices, which results in higher interface dominated recombination. Moreover, it has been predicted that optimum band offsets for higher efficiency solar cells may be achieved for cells with …
Redistribution Of Manganese Ion Implanted In Silicon, Arun Kumar Shunmugavelu
Redistribution Of Manganese Ion Implanted In Silicon, Arun Kumar Shunmugavelu
Electronic Theses and Dissertations
Ion implantation and the subsequent redistribution of manganese atoms in Czochralski Silicon (Cz-Si) and Floating Zone Silicon (Fz-Si) due to thermal annealing between 300 C and 1000 C is studied using Secondary Ion Mass Spectroscopy. The samples ion implanted at 340 C showed multiple peak formation above 900 C. This was not observed for the samples ion implanted at room temperature. Cz-Si and Fz-Si showed similar redistribution profiles.
Microwave Synthesis Of Nanocrystalline Hydroxy Apatite And Comparison Of Its Biomechanical Properties With Tio2 Structures, Saurabh Verma
Microwave Synthesis Of Nanocrystalline Hydroxy Apatite And Comparison Of Its Biomechanical Properties With Tio2 Structures, Saurabh Verma
Electronic Theses and Dissertations
Nanocrystalline hydroxyapatite (HAp) powder of size 10-20 nm was synthesized applying microwave radiation using calcium nitrate tetrahydrate and sodium phosphate dibasic anhydrous as the starting materials. Microwave power of 600 W and Ca/P ratio of 1.66 in the starting chemicals served as the major factors in the synthesis of nanocrystalline HAp powder. Phase composition and evolution were studied using X-ray diffraction (XRD) technique. Morphology, agglomeration and particle-size of the synthesized powder were studied using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) techniques. Energy Dispersive Spectrum (EDS) was used to determine the elemental composition of the powder. Thermal properties …
Film Growth Of Novel Frequency Agile Complex-Oxide Piezoelectric Material, Bindu Sreeramakavacham
Film Growth Of Novel Frequency Agile Complex-Oxide Piezoelectric Material, Bindu Sreeramakavacham
Electronic Theses and Dissertations
Piezoelectric materials are well known for their applications in surface (SAW) and bulk acoustic wave (BAW) devices such as oscillators, resonators and sensors. Quartz has been the main material used in such applications. Ternary calcium gallium germanate (CGG) structure-type materials, so-called langasites, recently emerged as very promising because of their piezoelectric properties superior to quartz. This thesis discusses the growth of langasite-type La3Ga5.5Ta0.5O14 (LGT) films by liquid phase epitaxy (LPE) technique and their chemical and structural characterization. In addition, the different techniques suitable for the growth of LGT are discussed and compared. To adjust the materials properties for given applications, …
Thermodynamic Studies On The Synthesis Of Nitrides And Epitaxial Growth Of Ingan, Zinki Monga
Thermodynamic Studies On The Synthesis Of Nitrides And Epitaxial Growth Of Ingan, Zinki Monga
Electronic Theses and Dissertations
Nitride semiconductor materials have been used in a variety of applications, such as LEDs, lasers, photovoltaic cells and medical applications. If incandescent bulbs could be replaced by white GaN LEDs, they would not only provide compactness and longer lifetime, but this would also result in huge energy savings. A renewed interest in InGaN emerged recently after it was discovered that the band gap for InN is 0.7eV, instead of the previously published value of 1.9eV. Thus InGaN solid solutions cover almost the whole visible spectrum, from a band gap of 3.34eV for GaN and 0.7eV for InN. Hence, InGaN can …
Polymer-Derived Si-Al-C-N Ceramics:Oxidation, Hot-Corrosion, And Structural Evolution, Yiguang Wang
Polymer-Derived Si-Al-C-N Ceramics:Oxidation, Hot-Corrosion, And Structural Evolution, Yiguang Wang
Electronic Theses and Dissertations
Polymer-derived ceramics are a new class of materials synthesized by thermal decomposition of polymer precursors. Previous studies have shown that the materials exhibit excellent thermo-mechanical properties and can be stable at temperatures up to 2000oC. Furthermore, the novel polymer-to-ceramics process enables the manipulation of the ceramic structures at the atomic/nano level by designing the chemistry of polymer precursors and controlling the pyrolysis conditions, thereby, the properties of ceramics. In this dissertation, oxidation/hot-corrosion behavior and the structural evolution of Si-Al-C-N ceramics have been studied. The structural evolution and crystallization behavior of the SiCN and SiAlCN ceramics are investigated using FT-IR, XRD, …
Polymer-Derived Ceramics: Electronic Properties And Application, Weixing Xu
Polymer-Derived Ceramics: Electronic Properties And Application, Weixing Xu
Electronic Theses and Dissertations
In this work, we studied the electronic behavior of polymer-derived ceramics (PDCs) and applied them for the synthesis of carbon nanotube reinforced ceramic nanocomposites and ceramic MEMS (Micro-Electro-Mechanical Systems) structures. Polymer-derived SiCN ceramics were synthesized by pyrolysis of a liquid polyureasilazane with dicumyl peroxide as thermal initiator. The structural evolution during pyrolysis and post-annealing was studied using FTIR, solid state NMR and Raman. The results revealed that the resultant ceramics consisted of SiCxNx-4 as major building units. These units were connected with each other through C-C/C=C bonds or by shearing N/C. The amount of sp2 free carbon strongly depends on …
Laser Metallization And Doping For Silicon Carbide Diode Fabrication And Endotaxy, Zhaoxu Tian
Laser Metallization And Doping For Silicon Carbide Diode Fabrication And Endotaxy, Zhaoxu Tian
Electronic Theses and Dissertations
Silicon carbide is a promising semiconductor material for high voltage, high frequency and high temperature devices due to its wide bandgap, high breakdown electric field strength, highly saturated drift velocity of electrons and outstanding thermal conductivity. With the aim of overcoming some challenges in metallization and doping during the fabrication of silicon carbide devices, a novel laser-based process is provided to direct metallize the surface of silicon carbide without metal deposition and dope in silicon carbide without high temperature annealing, as an alternative to the conventional ion implantation, and find applications of this laser direct write metallization and doping technique …
Development Of Thermally Processed Nanocomposites With Controlled Surfaces, Petya Georgieva
Development Of Thermally Processed Nanocomposites With Controlled Surfaces, Petya Georgieva
Electronic Theses and Dissertations
The ever increasing need for technology development requires the integration of inexpensive, light weight and high strength materials which are able to meet the high standards and specifications for various engineering applications. The intention of this work is to show that the suitable material selection and the utilization of plasma spray processing can be of potential interest to a large number of industrial, biomedical and everyday life applications. This research demonstrates also that plasma processing is a promising engineering tool for multifunctional coatings and near-net-shape manufacturing. Further, the theoretical and experimental results are combined in order to explain the mechanisms …
Magnetic Properties Of Sputter Deposited Fe-Based Amorphous Thin Films For Resonator Application, Chaitali China
Magnetic Properties Of Sputter Deposited Fe-Based Amorphous Thin Films For Resonator Application, Chaitali China
Electronic Theses and Dissertations
In this study we investigate the magnetic properties of Fe-based amorphous thin films. Fe1-x-y-zBxSiyCz, Fe80-xNixB20, Fe80-xMnxB20, and Fe73-xMnxB27 films were deposited on silicon and glass substrates in a DC and RF magnetron sputtering system. Inductive magnetic measurements were performed to investigate the magnetic properties, including induced anisotropy and magnetostriction, of the as-deposited and annealed films using an M-H Looper. The chemical composition of the films was characterized using secondary ion mass spectroscopy (SIMS). The physical thickness of the films was determined by use of a stylus profilometer. The M-H Looper studies indicated that the induced anisotropy (Hk) depends strongly on …