Preparation and Stability of Calcium Cadmium Hydroxyapatite

Calcium cadmium hydroxyapatites with various Cd doping(Cd/(Cd+Ca))were synthe- sized and characterized by X-ray diffraction,FT-IR spectroscope and FESEM.TG-DTG-DSC-MS and Toxicity Characteristic Leaching Procedure(TCLP)were used to determine their thermal and chem- ical stability.The results show that Cd~(2+)enters into the hydroxyapatites crystal lattice.And with molar ratios of Cd/(Cd+Ca)increasing,there forms the phases of Ca_(3.9)(Ca_(4.7)Cd_(0.7))(PO_4)_6(OH)_(1.8), Ca_(3.8)(Ca_(4.1)Cd_(0.73))(PO_4)_6(OH)_(1.8),Ca_(3.6)(Ca_(4.5)Cd_(0.76))(PO_4)_6(OH)_(1.6),Cd_5(PO_4)_3OH,respectively.All the calcium cadmium hydroxyapatites are thermal stable up to 500℃,and their thermal stabilities are enhanced with the increase of Cd doping,but their chemical stabilities become worse.