Controlled growth and investigations on the morphology and mechanical properties of hydroxyapatite/titania nanocomposite thin films

摘要

In this paper, the focus is on understanding the properties of nanocomposite hydroxyapatite (HAp)/titania (TiO_2) thin films with respect to TiO_2 concentration. HAp/TiO_2 nanostructured composite thin films with different TiO_2 concentrations were successfully fabricated by a simple sol-gel dip coating method. Highly stable HAp and TiO_2 sols were prepared prior to the formation of nanocomposite thin films. The coatings were performed under controlled dipping and heat treatment processes. Phase pure HAp and TiO_2 were well developed in the nanocomposite after the heat treatment and this was confirmed by XRD. The SEM and AFM analyses of HAp/TiO_2 nanocomposite coatings show the variation in the morphology as a consequence different TiO_2 concentration. This shows a reduction in the particle size to nanoscale due to the addition of TiO_2. The mechanical strength of the coating also increased upon the addition of TiO_2 as determined by nanoindentation. The composite thin films with 50 and 80 vol.% of TiO_2 show good mechanical strength when compared to other concentrations of TiO_2.