Depositing hydroxyapatite (HA) composite coating on Ni-Ti alloy by Al additive

In order to improve the bioactivity of biomedical NiTi alloys numerous NiTi disks were electrophoretcally coated by Hydroxyapatite/Aluminum composite particles in three main voltages from suspensions with different Al concentrations. In this paper the biocompatibility of deposited HA/Al composite on NiTi disks, including the bonding strength and corrosion behavior of the coating were investigated. The surface characterization of the coating by SEM showed HA particles bonded by Al particles, causing formation of a crack free coating on NiTi substrates. Moreover, the bonding strength of coating to NiTi substrate, in the case of HA/Al composite and in comparison with the pure HA coating, almost doubles. While, immersing coated samples in SBF for 1 week showed the growth of induced HA on HA/Al composite coating confirming the appropriate bioactivity of the deposited HA/Al composite on NiTi alloy.