Nano-sized α and β-TCP powders prepared by high temperature flame spray pyrolysis

Nano-sized α-TCP powders with spherical shape and non-aggregation characteristics were directly prepared by high temperature flame spray pyrolysis from the mixed spray solution of water and ethyl alcohol. The α-TCP powders prepared from the aqueous spray solution without ethyl alcohol had a bimodal size distribution with nanometer and micron sizes. Nano-sized and monodisperse α-TCP powders were prepared when the volume ratio (ethyl alcohol/distilled water, V/V) in the mixed solvent was of 40/60. The mean size of the nano-sized α-TCP powders was 32 nm. The composition ratio of calcium and phosphorous components of the nano-sized α-TCP powders was 1.49. The mean size of the spherical-like powders post-treated at a temperature of 600 °C was 57 nm. The mean size of the powders increased with increasing the post-treatment temperatures. The phase of α-TCP powders prepared by flame spray pyrolysis did not change at post-treatment temperatures below 700 °C. On the other hand, the powders post-treated at temperatures of 800 and 900 °C had single β phase of TCP.