Preparation of Beta‐Tricalcium Phosphate Powder Substituted with Na/Mg Ions by Polymerized Complex Method

Beta‐tricalcium phosphate (β‐TCP) powder doped with metal (Na ⁺ or Mg ²⁺ ) ions was prepared using a novel polymerized complex method that involves a reaction between metal ions and an organophosphorus chelating agent [(2‐phosphonobutane‐1.2.4‐tricarboxylic acid (PBTA)]. The precursors were uniformly gelled by the chelation and dehydration condensation of the carboxyl groups and phosphonic acid groups in PBTA, and metal (Ca ²⁺ , Na ⁺ , and Mg ²⁺ ) ions. When precursors with/without Na ⁺ ions were used, the β‐TCP phase crystallized through the α‐TCP phase, whereas when precursors containing Mg ²⁺ ions were used, it crystallized directly. The crystallization temperature of the β‐TCP phase from the precursors decreased with the addition of Na ⁺ and Mg ²⁺ ions. The lattice constants of each sample after heating the precursors at 1000°C were almost the same as those of β‐TCP powder doped with metal ions via a solid‐state reaction. The synthesized samples also had a stoichiometric composition. Heating the precursors above 550°C resulted in a unique chain structure, which remained unchanged even after the addition of Na ⁺ and Mg ²⁺ ions. However, at the same heating temperature, the particle size of the samples increased with the addition of Na ⁺ ions, but decreased with the addition of Mg ²⁺ ions.