Characterisation of HA-Si composite coatings on NiTi for biomedical applications

This study concerns with coating of hydroxyapatite-silicon composite on NiTi using a combination of electrophoretic deposition and reactive bonding. Hydroxyapatite and silicon were ball milled to join before electrophoretic deposition. The characterisation of samples was performed by scanning electron microscope (SEM) and X-ray diffraction analyses. Also Fourier transform infrared spectroscopy was used to determine the functional groups. Results show that ball milling yields homogeneous codeposition of hydroxyapatite and silicon particles. SEM images of the composite reveal a uniform and dense coating, because of the presence of silicon as a reactive bonding agent, as well as formation of SiO2, CaSiO3 and Ca3SiO5 during sintering.