Mosalagae Mosalagae; Russell Goodall; Mohammed Elbadawi
Abstract
Porous copper was fabricated by means of a powder metallurgy process applied to tape casting. Lost Carbonate Sintering (LCS) was employed to control porosity within the component during processing. The weight ratio of the potassium carbonate introduced into the matrix ranged from 30-40 wt%. Additives ...
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Porous copper was fabricated by means of a powder metallurgy process applied to tape casting. Lost Carbonate Sintering (LCS) was employed to control porosity within the component during processing. The weight ratio of the potassium carbonate introduced into the matrix ranged from 30-40 wt%. Additives such as; plasticizers, binders, dispersant and solvents were utilized to control the properties throughout the processes and ease fabrication. The component was debinded and sintered at 400 °C and 900 °C respectively, under vacuum. The potassium carbonate was removed from the sintered component via dissolution in water. By using X-ray Florescence (XRF) and Energy Dispersive X-ray Spectrometry (EDS) techniques, the effectiveness of the dissolution route at removing the space holder was investigated. The results show that porous copper produced in this way has porosity ranging from 75-85 % and pore size from 500-766 mm. The component produced has thickness ranging from 1300 -1800 mm.
Berrin Ikizler; Sumer Peker
Abstract
The damage given to the ZnO nanorod coating immobilized at the bottom of a rectangular channel by water flow is assessed in this work. The experiments were conducted in complete darkness to determine the inherent stability of the nanorod coating without the interfering effect of UV radiation. The quality ...
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The damage given to the ZnO nanorod coating immobilized at the bottom of a rectangular channel by water flow is assessed in this work. The experiments were conducted in complete darkness to determine the inherent stability of the nanorod coating without the interfering effect of UV radiation. The quality and morphology of the nanorod arrays before and after use were determined by x-ray diffraction, scanning electron microscopy; rod breakage, by dynamic light scattering; and the extent of erosion, by concentration and weight measurements. The effect of pH of the flowing water in the range 4£pH10, and the effect of the volumetric flow rate in the range, 3.3-33 cm 3 /s are investigated in this work as parameters. ZnO erosion reaches a low-level plateau in the pH range of 6£pH£10. Within this range, water velocity and alignment of the nanorods control the extent of dissolution. Dissolution of ZnO nanorods essentially takes place on the polar (0001)-Zn plane of ZnO, resulting in the formation of serrated surfaces. Furthermore, inclined rods joining at the top surface is subjected to further dissolution through pit formation originating at the junction interface, and extending outwards. ZnO nanorod arrays could be used as a photocatalyst in the photocatalytic water treatment processes, where the dissolution from nanorods is in the range of 2.0−2.5 wt% after 24 h of operation under a flow rate of 3.30 cm 3 /s (≈12 L/h), well under the requirements of World Health Organization.
