Microwave Augmented Fabrication and Evaluation of CNT-Reinforced Nanohydroxyapatite
Bioactive CNT reinforced hydroxyapatite nano-composite is synthesized by in-situ precipitation for use in load bearing orthopedic applications. Microwaves augment the synthesis, enhance the reaction rate, and institute energy savings. Heat and acid treated purified CNTs in microwaves are functionalized and dispersed in calcium nitrate tetrahydrate. Diammonium hydrogen phosphate is incorporated in calcium ion solution to furnish the required Ca:P ratio. Refluxing of the precursor solution is accomplished under microwaves. XRD shows the phase purity and crystallinity, FTIR spectroscopy indicates the fucntionalization of CNTs and SEM analysis depicts the nanoporous nanomorphology of synthesized powder. TGA measures the thermal endurance of product, showing good CNTs retention at high temperatures (1100°C) in nitrogen ambient, otherwise they get oxidized in air in that temperature range. CNT reinforced sintered biomaterial exhibits excellent consolidation and a Vicker hardness increment of 30%. The relation of between mechanical properties and sintering time is correlated by SEM.
Arshad Munir and Zaffar M. Khan
M. A. Akram et al., "Microwave Augmented Fabrication and Evaluation of CNT-Reinforced Nanohydroxyapatite", Advanced Materials Research, Vol. 326, pp. 110-120, 2011