In situ grown carbon nanotubes on carbon fibres and their effect on deposition of hydroxyapatite coating

Carbon nanotubes (CNTs) play an important role as reinforcement to improve the strength and toughness of hydroxyapatite (HA) coating due to its excellent mechanical properties and low density. However, the poor dispersion of the CNTs in the HA coating has limited its further application due to the fact that the CNTs are always introduced into the HA coating by means of CNT powders. To improve this condition, in situ grown CNTs instead of CNT powders are used to reinforce HA coating. The in situ grown CNTs are grafted on carbon fibres and then followed by an ultrasound assisted electrochemical deposition to prepare HA coating. The proposed research investigates the following aspects: microstructure of the in situ grown CNTs such as length, diameter and orientation; effect of in situ grown CNTs on the morphology and crystal structure of HA coating prepared by ultrasound assisted electrochemical deposition; and dispersion of CNTs in the HA coating. The novel aspect of the proposed research is that the in situ grown CNTs instead of CNT powders are used to reinforce HA coating. The CNTs could keep their three-dimensional network structure and form a uniform distribution within the HA coating. A close interfacial bonding between the HA and the CNTs is achieved. The CNT reinforced HA coating for carbon fibres prepared in this work should have potential application as scaffolds for tissue engineering and as fillers for composite materials.