Preparation, characterization and mechanical performance of dense β-TCP ceramics with/without magnesium substitution

Beta-tricalcium phosphate (beta-TCP) powder was prepared by a two-step process: wet precipitation of apatitic tricalcium phosphate [Ca-9(HPO4)(PO4)(5)(OH)] (beta-TCP 'precursor') and calcination of the precursor at 800 degrees C for 3 h to produce beta-TCP. Magnesium-substituted tricalcium phosphate (beta-TCMP) was produced by adding Mg(NO3)(2) center dot 6H(2)O into Ca(NO3)(2) solution as Mg2+ source before the precipitation step. The transition temperature from beta-TCP to alpha-TCP increases with the increase of Mg2+ content in beta-TCMP. beta-TCMP with 3 mol.% Mg2+ has beta-TCP to alpha-TCP transition temperature above 1,300 degrees C. Dense beta-TCMP (3 mol.% Mg2+) ceramics (similar to 99.4% relative density) were produced by pressing the green bodies at 100 MPa and further sintering at 1,250 degrees C for 2 h. The average compressive strength of dense beta-TCP ceramics sintered at 1,100 degrees C is similar to 540 MPa, while that of beta-TCMP (3 mol.% Mg2+) ceramics is similar to 430 MPa.