Synthesis and characterization of machinable calcium phosphate/lanthanum phosphate composites

Hydroxylapatite (HA) and tricalcium phosphate (TCP) composites with lanthanum phosphate were prepared with pressureless air sintering at 500, 700, 900, 1100 and 1300 degrees C for 2h. The composites were characterized in terms of phase stability during sintering, microstructural evaluation with XRD, SEM and machinability with simple drilling operation. At sintering temperatures higher than 700 degrees C, hydroxylapatite and lanthanum phosphate phases reacted and formed CagLa2(PO4)(6)O-2. On the other hand, tricalcium phosphate and lanthanum phosphate composites were stable up to 1100 degrees C However partial reaction was observed during sintering at 1300 degrees C. As a result, tricalcium phosphate and lanthanum phosphate composites sintered at 1100 degrees C showed phase stability insuring weak interface. Thus, these composites fulfilled the requirement for machinability (C) 2007 Elsevier B.V. All rights reserved.