Study On The Fabrication Of Hydroxyapatite And Carbon Nanotube Composites

This work reports the properties and crystal structure of hydroxyapatite (HAp), domestic and foreign situations of research and application about hydrox-yapatite, the problems and the future development of hydroxyapatite material, the merit and the shortage of Carbon nanotube as a phase with higher strength and toughness and the developing direction of Carbon nanotube. The study of Carbon nanotube/hydroxyapatite (CNTs/HAp) ceramic was related to synthesis of hydroxyapatite powder and the fabrication of CNTs/HAp ceramic in details.Hydroxyapatite powder was synthesized from Ca(NO3)2·4H2O, P2O5 and dehydrated alcohol with Sol-gel method, then XRD and SEM were employed to investigate the crystal structure and the pure consideration of Hydroxyapatite powder. It is showed that the resultant hydroxyapatite powder is a spherical or ellipsoidal granule with a uniform size of 23.2nm, pure consideration rather high and the distributing of size being well-proprotioned.The well-decentralized CNTs suspending alcohol liquid could be obtained by puring and modifying CNTs with mixed-acid and ethanol process. The disper-sivity mechanism of CNTs have been analyzed by SEM, TEM, FTIR and Zeta. The foreign substance Cu and Zn were gotten rid of, as a result, the CNTs has better distribution capability of the particles has been changed in the polymer, and caps of CNTs were removed and contained the organic foundation -OH and–COOH, which provided a better dispersing condition for CNTs.CNTs/HAp composite powder was prepared by ball milling and ultrasonic dispersion, and the samples were sintered in hot extrusion vacuum. Compared to the mechanical properties of HAp, the relation of the contents of CNTs, the mechanical properties and microstructure of CNTs/HAp ceramic were investinga-ted. The dispersive constitution of composite powder is observed by SEM, and the phase constitution and the the microstructure of composite ceramic were studied by XRD and SEM. The results are that the crystallization aspect, the bending strength and the fracture toughness of hydroxyapatite will be improved when carbon nano-tube is added to hydroxyapatite. The bending strength of HAp ceramic acted 66.4MPa,the fracture toughness of that acted 0.88 MPa·m1/2, and the bending strength of CNTs/HAp ceramic(the content of CNTs acted 2% ) sintered at 1200℃in hot extrusion vacuum attainabilitied 105.6MPa,the fracture toughness of that attainabilitied 1.8MPa·m1/2, the bending strength is improved about 59%, and the fracture toughness is increased about 105%.