Journal of Nanoparticle Research

, Volume 9, Issue 5, pp 807–815 | Cite as

Calcination of Rod-like Hydroxyapatite Nanocrystals with an Anti-sintering Agent Surrounding the Crystals

  • M. Okada
  • T. Furuzono


Sintering-free nanocrystals of calcined hydroxyapatite (HAp) having a rod-like morphology were fabricated by calcination at 800°C for 1 h with an anti-sintering agent surrounding original HAp particles and the agent was subsequently removed after calcination. The original HAp particles having a rod-like morphology with a size ranging from 30 to 80 nm (short axis) and 300 to 500 nm (long axis) were prepared by wet chemical process, and poly(acrylic acid, calcium salt) (PAA-Ca) was used as the anti-sintering agent. In the case of calcination without additives, the mean size of HAp crystals dispersed in an ethanol medium increased by about 4 times and the specific surface area of the crystals exhibited a 25% decrease compared to those of the original HAp particles because of calcination-induced sintering among the crystals. On the other hand, the HAp crystals calcined with the anti-sintering agent, PAA-Ca, could be dispersed in an ethanol medium at the same size as the original particles, and they preserved the specific surface area after calcination. These results indicate that PAA-Ca and/or its thermally decomposed product, CaO, surrounded the HAp particles and protected them against calcination-induced sintering during calcination. The HAp crystals calcined with PAA-Ca showed high crystallinity, and no other calcium phosphate phases could be detected after washing with water.

Key words

hydroxyapatite nanocrystal calcination dispersion thermal decomposition sintering 


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We thank Dr. Y. Yokogawa and Dr. K. Sato of the Advanced Manufacturing Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), for helpful discussions. This work was supported by a Research Grant for Cardiovascular Diseases from the Ministry of Health, Labour and Welfare, Japan.


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Copyright information

© Springer Science+Business Media, Inc. 2006

Authors and Affiliations

  1. 1.Department of Bioengineering, Advanced Medical Engineering CenterNational Cardiovascular Center Research InstituteSuita, OsakaJapan

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