Emulsion Conditioning: A Route to Stronger and More Reliable Hydroxyapatite Ceramics

The production of high strength hydroxyapatite ceramics has to date been hindered by the formation of agglomerates during the powder processing stages. In this paper it is shown how the introduction of an emulsion conditioning stage has modified the nature of the agglomerates to produce a “soft” deformable powder leading to improvements in both strength and consistency of sintered HA. On sintering at 1100°C for 2 hours, the conventionally processed and the emulsion refined material produced fracture strengths of 70.4 MPa and 201.1 MPa, respectively. The effect of powder agglomeration on densification during both the initial and intermediate/late stages of sintering is discussed.