Browsing by Author "Arendse, Christopher J"

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    Grain structure orientational change in Ti6Al4V alloys induced by sea water quenching and novel stress relief annealing process
    (Materials Chemistry and Physics, 2023) Bolokang, Amogelang S; Mathabathe, Maria N; Motaung, David E; Arendse, Christopher J; Swart, Hendrik C
    We report on the microstructures and properties of Ti6Al4V alloys, which were achieved upon quenching in sea water medium with potential high cooling rate. The Ti6Al4V alloys were quenched at 1000 and 1100 ◦C, respectively. Moreover, the effect of post-quenching annealing performed at 900 ◦C was analyzed. As a result, the quenched alloy experienced surface thermal stress, due to rapid cooling and thermal shock, due to exposure to high temperature annealing.
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    Influence of Synthesis Method on Structural, Morphological, Magnetic, and Antimicrobial Properties of Fe-Ag Nanoparticles
    (Journal of Inorganic and Organometallic Polymers and Materials, 2023) Noukelag, Sandrine Kamdoum; Ngqoloda, Siphelo; Arendse, Christopher J; Mewa-Ngongang, Maxwell
    This contribution reports on the development of two versatile and efficient methods, namely the green and gamma radiolysis for Fe-Ag nanoparticles (NPs) synthesis, characterization, and further their growth inhibition potential on some spoilage microorganisms. Green Ag/Fe2O3 NPs were obtained at Fe-Ag [3:1], annealing temperature of 800 °C for 2 h, and gamma irradiated Ag/Fe3O4 NPs were obtained at Fe-Ag [7:1], a 50 kGy dose. The characterization techniques were performed with these two samples whereby the sizes from crystallographic and microscopic analyses were 39.59 and 20.00 nm for Ag/Fe2O3 NPs, 28.57 and 15.37 nm for Ag/Fe3O4 NPs, respectively. The polycrystallinity nature observed from X-ray diffraction was in accordance with the selected area electron diffraction. The vibrational properties confirmed the presence of bimetallic Fe-Ag NPs with the depiction of chemical bonds, Fe–O and Ag–O from attenuated total reflection-Fourier transform infrared spectroscopy and elements Ag, Fe, O from energy-dispersive X-ray spectroscopy analyses. The magnetic properties carried out using a vibrating sample magnetometer suggested a superparamagnetic behavior for the Ag/Fe2O3 NPs and a ferromagnetic behavior for the Ag/Fe3O4 NPs. Overall, the green Ag/Fe2O3 NPs successfully inhibited the growth of spoilage yeasts Candida guilliermondii, Zygosaccharomyces fermentati, Zygosaccharomyces florentinus, and spoilage molds Botrytis cinerea, Penicillium expansum, Alternaria alstroemeriae.