Carbonated hydroxyapatites(CHA) were rapidly and continuously synthesized in supercritical water by using a tubular reactor. The effects of reaction time and the ratio of PO43-/CO32-on the apatite structure were investigated by using XRD, FTIR and TEM. Results showed that 30 seconds were enough to produce fully crystalline CHA nano-rods, ca. 20×70 nm in size, at 380 ℃ and 24 MPa. When the ratio of PO43-/CO32-was not less than 1, the CO32-ions mainly substituted for PO43-in apatite structure; but CO32-ions could react with Ca2+ to form CaCO3 phase when the ratio of PO43-/CO32-was less than 1.
