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.
Mohammed Elbadawi; James Meredith; Mosalagae Mosalagae; Ian M. Reaney
Abstract
In this study, we have developed hydroxyapatite (HA) scaffolds for synthetic bone graft from nano-sized HA particles using ceramic extrusion. We also demonstrate that these HA scaffolds show enhanced compressive strength (29.4 MPa), whilst possessing large pore sizes (> 600 µm) that are suitable ...
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In this study, we have developed hydroxyapatite (HA) scaffolds for synthetic bone graft from nano-sized HA particles using ceramic extrusion. We also demonstrate that these HA scaffolds show enhanced compressive strength (29.4 MPa), whilst possessing large pore sizes (> 600 µm) that are suitable for bone grafting. The extrusion process involved forming a ceramic paste by mixing the HA powder with a binder and distilled water. The ceramic paste was then fabricated using a ram extruder that was fitted with a honeycomb die to impart large, structured pores. Several green bodies were extruded and then subjected to the same drying and thermal debinding treatment. The samples underwent three different sintering temperatures and two varied dwell times, in order to determine the optimum sintering parameters. The scaffolds were then analysed for their chemical, physical, mechanical and biological properties to elucidate the effects of the sintering parameters on extruded HA scaffolds. The results revealed that the nano-sized particles exhibited a high sinterability, and XRD analysis showed phase purity until 1300 o C. At 1300 o C, trace amounts of phase impurities were detected, however, scaffolds sintered at this temperature exhibited the highest mean compressive strength. The findings demonstrated that traces of phase impurities were not detrimental to the scaffold’s compressive strength. In addition, scanning electron microscopy and density measurements revealed a highly densified solid phase was attained.