Nanocomposites and nanomaterials

Variation of Hardness of the Bioceramics based on Hydroxyapatite by adding the Multi-walled carbon nanotubes 

Barabashko M. S.1,2, Tkachenko M. V.3, Ponomarev A. N.2,4, 
Rezvanova A. E.5, Yasnopolskiy D. Yu.3

1B.Verkin Institute for Low Temperature Physics and Engineering of NAS of Ukraine,47 Nauky Ave., Kharkiv, 61103, Ukraine
2National Research Tomsk Polytechnic University, 30 Lenin Ave., 634050 Tomsk, Russia
3V. Karazin Kharkiv National University, 4, Maidan Svobody, 61077, Kharkiv, Ukraine
4Institute of Strength Physics and Materials Science of SB RAS, 2/4 Akademichesky Ave., Tomsk 634055, Russia
5Tomsk State University of Control Systems and Radioelectronics, 40 Lenin Ave., 534050 Tomsk, Russia
e-mail: msbarabashko@gmail.com

Ceramics for medical applications with high bioactivity and improved mechanical characteristics based on hydroxyapatite Ca10(PO4)6(OH)2 with a content of multi-walled carbon nanotubes (MWCNTs) have been synthesized and characterized. Hydroxyapatite(HA) has been prepared via the reaction of calcium carbonate and orthoposphoric acid. The mass ratio of reagents was chosen so as to obtain stoichiometric HA. The morphology and structure of the powder of MWCNTs have been characterized by transmission electron microscope JEOL JEM-2100F before mechanical mixing of the MWCNTs and HA powders. According to TEM investigation the synthesized powder of nanotubes consists mainly from multi-walled nanotubes with non-defect structure and does not contain amorphous carbon. The most part of the MWCNTs in the powder has distributions of outer diameter 10-20 nm. According to the EDX analysis the amount of the carbon atoms in the MWCNTs powder is near 99%. The НА bioceramics with concentrations of 0.05 wt. %, 0.1 wt. %, 0.2 wt. % of MWCNTs have been produced in an argon atmosphere at temperature of 1100 C. The microstructure and the phase composition of synthesized bioceramics have been determined by XRD, TEM, IR. The Vickers hardness of the HA-MWCNTs composites is significantly higher than that of pure hydroxyapatite. It was shown that the greatest hardness is achieved when the content of impurities of multiwalled carbon nanotubes is about 0.05 wt. %.