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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Exotermní intermetalické směsi, jejich příprava a hodnocení / The preparation and evaluation of intermetallic exothermic metallic blends

Mynarčík, Pavel January 2019 (has links)
During exothermic reactions a significant amount of heat is released. This heat can be further utilized for heating up chemical substances, chemical reaction initiation or welding. The first part of this thesis contains survey of thermodynamics and thermodynamics and thermochemistry of exothermic reactions, overview of commonly used exothermic processes as thermites and NanoFoil, summary of intermetallic systems and possibilites of powder metallurgy as a fabrication process of exothermic powder blends. Based on the survey part is designed experimental powder blend obtained by powder metallurgy. 18 powder samples were analysed; chemical composition was obtained by XRD and EDS analysis, on scaning electron microscope the morphology of powder particles was evaluated and by differential scanning calorimetry (DSC) the temperature of exothermic intermetallic reaction was determined. Furthermore a bulk intermetallic sample was sintered by spark plasma sintering process (SPS).
2

Reaction Velocities In Free Standing Aluminum And Cooper Oxide This Films

Erickson, Matthew 01 January 2009 (has links)
In this work we investigate the reaction propagation velocity of aluminum and copper oxide Metastable Intermolecular Composites (MIC's). All samples were deposited in a magnetron sputtering system using 2 aluminum targets and 2 copper targets. The copper is sputtered in an oxygen rich environment in order to obtain copper oxide rich films. Three different layer structures are used for various measurements that are composed of alternating 20 layer pairs, 30 layer pairs, and 40 layer pairs. All layer pairs maintain a constant total thickness of 3.2 microns. Each layer structure can be prepared independent of a substrate and is measured with the use of photodiodes or with direct device contact. Aluminum and copper oxide structures have potential use as propellants and additives to explosives, thus, accurate propagation velocity or burn rate measurements are important. The developed measurement system for burn rate measurements of Al/CuO MIC's can achieve and accuracy of 0.1 m/s. In order to determine the velocity limiting characteristics, MIC's on glass and silicon substrates were measured as well as free standing Al/CuO MIC's. Separate burn rate measurement devices were created in order to handle the variety of substrates. In addition, the ignition energy of the Al/CuO MIC was studied to further characterize the samples. This was done using both voltage and current probes of a reacting sample. Rutherford backscattering spectroscopy (RBS) was used for sample composition calibration. The pre- and post-reaction Al/CuO MIC's were also characterized by transmission electron microscopy (TEM).

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