Novel titanium - hydroxyapatite biocomposites by mechanical milling

Titanium with nano hydroxyapatite (nHA) as well as with micron size hydroxyapatite was ball milled for various time intervals. The milled powders were characterized using X-Ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) techniques. The XRD results show peak broadening with increase in milling time indicating the formation of nanocomposite with titanium and HA phases. Relatively, titanium was found to be more reduced in size with increase in milling time than HA in the composite. The EDX results indicated the presence of Ca and P in the titanium matrix. elemental mapping showed homogeneous distribution of Ti, Ca and P after 16 h of ball milling in all the composites. TEM micrographs also revealed the presence of nanocrystals. The powders were compacted, sintered and immersed in simulated body fluid (SBF), which has the same ion concentration as that of the human body plasma, to study bioactivity under physiological condition. After immersion in SBF for 1 week, the compacts were observed in SEM and all the composites were found to be bioactive with the formation of bone like apatite layer on the surface. The morphology of the apatite formed was globular and more dense for the composite prepared using nano HA compared to micron size HA. © CSIR-National Metallurgical Laboratory, Jamshedpur-831007, India, 2011.