Novel machinable calcium phosphate/CaTiO3 composites

Hydroxylapatite/CaTiO3 and tricalcium phosphate/CaTiO3 composites were prepared by pressureless air sintering and characterized in terms of phase stability, microstructure and pole drilling for their suitability for machining. In hydroxylapatite/CaTiO3 composites, Ti incorporation into the apatite structure caused lattice shrinkage and eventual decomposition of the hydroxylapatite associated with the formation of a-tricalcium phosphate during sintering at 1100 degrees C. Later, a-tricalcium phosphate disappeared at 1300 degrees C, possibly reacting with CaTiO3 at the expense of both phases. On the other hand, tricalcium phosphate/CaTiO3 composites were thermally stable up to 1100 degrees C insuring a weak interface between the components, which is one of the requirements for machinability in ceramic composites. Drilling tests also verified their suitability for machining. (C) 2010 Elsevier Ltd and Techna Group S.r.l. All rights reserved.