Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 30 for “"Boride"”.
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Mechanical properties of boride based ceramics
… on the elevated mechanical properties of diboride based materials at room and elevated temperatures. These materials include a ZrB<sub>2</sub> ceramic, a ZrB<sub>2</sub>-WC-SiC ceramic, and a (Hf,Mo,Nb,Ta,W,Zr)B<sub>2</sub> high entropy boride (HEB). The room temperature flexural strength …
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Synthese, Charakterisierung und Materialeigenschaften borreicher Boride und Boridcarbide des Magnesiums und Aluminiums
… Synthese und Charakterisierung neuer borreicher Boride und Boridcarbide des Magnesiums. Es konnten Einkristalle von MgB7, MgB12, MgB17, B12MgC2 (orthorhombisch), B24Mg2C, B12MgC2 (monoklin) und B50Mg3C8 erhalten und durch RSA sowie WDX charakterisiert werden. Alle Synthesen fanden aus den …
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Synthesis and indentation of boride and carbide coated carbon nanotube composite microstructures
… two methods: (i) static CVD with a hafnium diboride precursor (Hf[BH4]4) leading to coating thicknesses ranging from 3nm to 50 nm; and (ii) through cycles of elasto-capillary imbibition and pyrolysis of a silicon oxycarbide (SiOC) polymer derived ceramic leading to coating thickness from 8 nm …
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The processing and characterization of aluminum boride flake-reinforced aluminum matrix composites
AlB$\sb2$ flakes in an aluminum matrix offer the potential for greatly increased composite mechanical and wear properties because of their high aspect ratio, very high mechanical properties and good wetting to the aluminum matrix. This thesis describes, for the first time, an approach to the …
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Remote Plasma Chemical Vapor Deposition of Zirconium Boride: Growth and Diffusion Barrier Characteristics
High-quality ZrB2 thin films have been deposited at substrate temperatures as low as 300°C by a new method: remote hydrogen plasma chemical vapor deposition from the single-source precursor zirconium borohydride, Zr(BH 4)4. Carrying out the deposition in the presence of atomic hydrogen …
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Characterization of thermally diffused bordie layers on AISI 1018 steel : residual stresses (by synchrotron radiation) and microhardness
… a thermal diffusion process in which needle like boride layers are formed at the surface of the metallic substrate. The boride coatings formed by the diffusion process have high hardness and strong ware and corrosion resistance. In order for coatings of this nature to be industrially successful, …
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Synthesis and oxidation behavior of Cr alloyed uranium borides at high temperatures
… fuels has arisen. In recent years, uranium boride (as a tetraboride and diboride) has been further investigated as a candidate fuel form for its high thermal conductivity, high melting point, high uranium loading, and potential for dual use as a fuel and burnable absorber. In this work, the …
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Multi-component boron coatings on low carbon steel AISI 1018
… into the metal substrate forming metallic boride layers, providing complex properties of B-Me-Fe system. To study multi-component boron coatings on low carbon steel AISI 1018, the simultaneous powder pack method of boronizing and metalizing was selected to perform the coatings. One B-Fe …
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Surface Engineering and Characterization of Laser Deposited Metallic Biomaterials
… improve the wear resistance of the TNZT system boride reinforcements were carried out in the matrix using LENS processing. The tribological response of the metal matrix composites was studied under different conditions and compared with Ti-6Al-4V. Usage of Si3N4 balls as a counterpart in the …
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The Tandem Inter [4+2]/[3+2] Cycloadditions of Nitroalkenes: The Bridged-Mode
… nitroso acetals that were reduced using nickel boride to provide enantiomerically enriched aminocyclopentanes in good yields and high enantiomeric excess. Additionally, the Lewis acid employed in the $\lbrack 4 + 2\rbrack$ cycloaddition was found to impart a remarkable influence on the …
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Synthesis and development of boron nanotubes and metal/ceramic-carbon nanotube composites
… the use of solid boron precursors - magnesium boride and magnesium borohydride, magnesium and nickel boride as co-catalysts, and porous MCM-41 zeolite as the growth template. Experimental parameters, such as temperature, grinding of constituents and starting precursor-catalyst-template …
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Material Degradation Studies in Molten Halide Salts
… in the molten KCl-MgCl2-NaCl salt. The borided alloys exhibited better resistance to molten salt attack, where the boride layer in the exposed alloy was still intact, non-porous, and strongly adhered to the substrate. The alloys also did not show any compensation in their properties …
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Thermochemical modeling and chemical vapor deposition of two-phase borides in the Hf-Si-B-Cl-H system
… engine and aerospace vehicle applications. Boride-based coatings that form a protective layer during oxidation have been found to withstand these extreme conditions. Chemical vapor deposition has been chosen as a viable processing technique for producing these coatings. It is expected that …
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Rhenium, osmium and iridium diborides by mechanochemistry: Synthesis, structure, thermal stability and mechanical properties
Borides are implemented in a range of industrial applications due to their unique mechanical, electrical, thermal and catalytic properties. In particular, transition metal diborides are of special interest. In the recent years, borides of rhenium (Re), osmium (Os) and iridium (Ir) have been studied …
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Synthese, Einkristallzüchtung und Charakterisierung von binären Siliciumboriden
… und Charakterisierung neuer binärer Siliciumboride sowie die Untersuchung bereits bekannter Phasen dieses Systems. Durch die Anwendung der Hilfsmetallbadmethode konnte ein einfacherer Zugang zu diesen Verbindungen durch eine entscheidende Absenkung der Reaktionstemperaturen aufgezeigt werden. …
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Novel micron- and nano-scale energetic materials for advanced gun propulsion, their material properties, and their effects on ballistic performance
… temperature of 950 C when using Magnesium Boride (MgB2) in the thermally induced CVD process. The small scale synthesis of boron nanotubes /nanofibers carried out using MgB_2 powder, Nickel Boride (Ni2B) powder catalysts and mesostructured hexagonal framework zeolite powder was successfully …
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