Thermal crystallisation of amorphous calcium phosphate to α-tricalcium phosphate

Dehydration and thermal change in amorphous calcium phosphate (ACP) have been studied by thermogravimetry, differential thermal analysis and X-ray diffractometry. ACP retained water up to about 773 K. Immediately after the dehydration, a high-temperature form of calcium phosphate, α —Ca₃(PO₄)₂ (α -TCP), was obtained by ignition of ACP precipitated from the solution with a high degree of supersaturation. The kinetics of thermal crystallisation of α-TCP from ACP were also studied.