Low-temperature mineralization sintering process of bioactive glass nanoparticles

Inspired by biomineralization in nature which provides the formation of various inorganic minerals under mild temperatures and pressures conditions, we report here the low-temperature mineralization sintering process (LMSP) of SiO2CaOP2O5 bioactive glass nanoparticles (BGNs). The ternary BGNs were successfully synthesized by an alkali mediated solgel method. The obtained glass nanoparticles, having around 30nm in diameter, were sintered in a mold under an applied pressure of 300MPa at 120 °C with an aid of small amount of simulated body fluid (SBF) solution. Under the condition, BGNs were densified through biomineralization with a formation of amorphous calcium phosphate phase which filled up the interparticle boundaries and bonded each glass nanoparticles. The relative density and Vickers hardness of the sintered BGNs were sufficiently high, 86% and 2.09 GPa, respectively, although the low sintering temperature. These values were higher than those of BGNs sintered by the same procedure with no aqueous solution (57%, 0.68 GPa), distilled water (77%, 1.52 GPa), and even the conventionally sintered BGNs at 550 °C (69%, 0.93 GPa) and 850 °C (81%, 2.02 GPa). These results suggest that the LMSP is a promising and cost-effective process for obtaining bioactive glass and ceramic bulk materials at low temperature.