Tailoring the Microstructure of Sol–Gel Derived Hydroxyapatite/Zirconia Nanocrystalline Composites
1 Department of Technological Sciences and Development, Campus de Ponta Delgada, Azores University, 9501-801, Ponta Delgada, Açores, Portugal
2 Physics Department of FCT/UNL, CEFITEC—Centre of Physics and Technological Research, Quinta da Torre, 2829-516, Caparica, Portugal
3 CIRN—Centre of Research in Natural Resources, 9501-801, Ponta Delgada, Açores, Portugal
Nanoscale Res Lett 2011, 6:20 doi:10.1007/s11671-010-9766-zPublished: 31 August 2010
In this study, we tailor the microstructure of hydroxyapatite/zirconia nanocrystalline composites by optimizing processing parameters, namely, introducing an atmosphere of water vapor during sintering in order to control the thermal stability of hydroxyapatite, and a modified sol–gel process that yields to an excellent intergranular distribution of zirconia phase dispersed intergranularly within the hydroxyapatite matrix. In terms of mechanical behavior, SEM images of fissure deflection and the presence of monoclinic ZrO2 content on cracked surface indicate that both toughening mechanisms, stress-induced tetragonal to monoclinic phase transformation and deflection, are active for toughness enhancement.