Browsing by Author "Sibuyi, Praise"

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    Irradiation induced effects on 6h-SIC
    (University of the Western Cape, 2012) Sibuyi, Praise; Maaza, M.
    The framework agreement in the year 2000 by the international community to launch Generation IV program with 10 nations, to develop safe and reliable nuclear reactors gave rise to the increased interest in the studies of SiC and the effect of different irradiations on solids. Silicon carbide is a preferred candidate used in harsh environments due to its excellent properties such as high chemical stability and strong mechanical strength. The PBMR technology promises to be the safest of all nuclear technology that have been developed before. SiC has been considered one candidate material being used in the fabrication of pebble bed fuel cell. Its outstanding physical and chemical properties even at high temperatures render it a material of choice for the future nuclear industry as whole and PBMR in particular. Due to the hostile environment created during the normal reactor operation, some of these excellent properties are compromised. In order to use this material in such conditions, it should have at least a near perfect crystal lattice to prevent defects that could compromise its strength and performance. A proper knowledge of the behavior of radiation-induced defects in SiC is vital. During irradiation, a disordered crystal lattice occurs, resulting in the production of defects in the lattice. These defects lead to the degradation of these excellent properties of a particular material. This thesis investigates the effects of various radiation effects to 6H-SiC. We have investigated the effects of radiation induced damages to SiC, with a description of the beds and the importance of the stability of the SiC-C interface upon the effects of radiations (y-rays, hot neutrons). The irradiated samples of 6H-SiC have been studied with various spectroscopic and structural characterization methods. The surface sensitive techniques such as Raman spectroscopy, UV-Vis, Photoluminescence and Atomic Force Microscopy will be employed in several complimentary ways to probe the effect of irradiation on SiC. The obtained results are discussed in details.
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    Nano-rods WO3-δ for electrochromic smart windows applications
    (University of the Western Cape, 2006) Sibuyi, Praise; Maaza, Malik; Knoesen, D.; Dept. of Earth Science; Faculty of Science
    Tungsten oxide is a good electrochromic material which has been used in the construction of smart windows through visible modulation. These smart materials can reversibly change their optical properties with the application of an external voltage. Their ability to lighten and darken on command is ideally suited for energy-efficiency windows. The process itself or the overall reaction should respond in seconds and as quick as possible. The goal of this project was to prepare epitaxial well defined tungsten oxide nanorods by the thermal evaporation technique.