Effect of the Mg super(2+) Substitution on the Sintering Behavior and Compressive Strength of Doped B-TCP/CPP Ceramics

beta -Tricalcium phosphate ( beta -TCP) ceramics are of interest for bone requirements implants due to resoption behavior. The mechanical properties of beta -TCP, however, are not yet sufficient to allow load bearing application of implants. The aim of this work was to investigate the effect of Mg super(2+) substitution on the strength sintered TCP. Due to promotion of a liquid phase at 1200[degrees]C, Calcium pyrophosphate (CPP-C sub(2)P sub(2)O sub( 7)) was used to improve the sintering of the samples. The introduction of CPP was promoted by use of a Ca/P molar ratio of 1.45. The powders were synthesized using a mixture of Ca (OH) sub(2) suspension and diluted H sub(3)PO sub(4) with addition of MgO and calcined at 750 [degrees]C, 900 [degrees]C and 1050 [degrees]C. The cold isostatic pressing compacts were sintered at 1200 [degrees]C and 1300 [degrees]C, respectively. It was shown that a small Mg content (1.5 mol%) increased both compressive strength and fractional density of the TCP material sintered at 1200 [degrees]C from 132 + or - 39 MPa at 92.1 % of fractional density to 193 + or - 29 MPa at 94.5 % of theoretical density. Higher amounts of Mg inhibited the grain growth provoking a increase of the boundary mobility activation energy. Abnormal grain growth (AGG) was observed after sintering at 1300[degrees]C, as result CPP - liquid phase formation. Increase of Mg content promoted AGG, due to inhibition of grain growth during normal grain growth resulting in a increase of the residual elastic energy of the system.