Solid-phase steam-assisted synthesis of hydroxyapatite nanorods and nanoparticles

Abstract

This article reports a novel and facile solidbased steam-assisted conversion method for the synthesis of hydroxyapatite (HAP, Ca 10(PO4)6(OH)2) nanorods and nanoparticles. After steam treatment at 180 °C for 20 h, the wet solid of brushite (CaHPO4·2H2O), which was precipitated from reaction between calcium nitrate [Ca(NO3)2] and diammonium hydrogen phosphate [(NH4)2HPO4], was transformed to HAP nanorods with dimension of 100-300 nm in length and 56 ± 10 nm in diameter through a solid-gas reaction. By the same steam treatment, the dried brushite was converted to nanoparticles of HAP with small aspect ratio and particle size of 70 ± 18 nm. As compared with commercial HAP material, the nanostructured HAP materials exhibited superior sinterability in terms of density and hardness as well as excellent thermal stability. This simple, organic-free and cost-effective synthesis route with low reactant volume offers high potential for large-scale production of nanostructured HAP. © Springer Science+Business Media, LLC 2010.