Structure and compression strength of hydroxyapatite/titania nanocomposites formed by high energy ball milling

Hydroxyapatite/titania (HA/TiO2; TiO2 - 0, 5, 10, 15, 20, 25 wt.%) nanocomposites were produced by high energy ball milling (HEBM) at 50 Hz for 1 h from starting materials particle sizes of HA <100 mu m and TiO2 <25 mu m. X-ray Diffraction and Field-Emission Scanning Electron Microscopy results indicated that hydroxyapatite and Anatase were the major phases after mechanical milling with particle size less than 100 nm. After 1 h of convenient thermal treatments at 1000-1200 degrees C, beta-tricalcium phosphate and calcium titanium oxide phases were the main crystalline phases irrespective of the sintering temperature. While Rutile phase was observed at 1200 degrees C, the presence of Rutile as a secondary phase in the microstructure of the composites has led to an increase of the compressive strength up to 330 MPa in the nanocomposites containing 25% TiO2. Longer sintering time (3 h) at 1200 degrees C has not increased the compressive strength. The produced nanocomposites have showed a moderate deformability where a reduction in height (strain) ranging between 1% and 5.6% was attained at the point of the highest compressive stress. (C) 2015 Elsevier B.V. All rights reserved.