Mechanoelectrochemical synthesis and properties of porous nano-Ti–6Al–4V alloy with hydroxyapatite layer for biomedical applications

Formation of porous morphology in nanocrystalline mechanically alloyed and electrochemically etched Ti–6Al–4V biomedical alloy was investigated. The alloy was electrochemically etched in a mixture of H3PO4 and HF. The electrochemical etching results in broad range from micro(nano)-macropores formation in the surface layer, with diameter in the range of 3 nm–60 µm. On the etched surface hydroxyapatite was electrochemically deposited by using 0.042 M Ca(NO3)2 + 0.025 (NH4)2HPO4 + 0.1M HCl electrolyte. In this way bioactive surface was prepared. The pores in the surface acts as anchors for the hydroxyapatite, which grows inside them. Due to the porous morphology, the etched as well as HA deposited surface is promising for hard tissue implant applications. The nanocrystalline alloy has a nanohardness and Young modulus in the range of 993–1275 HV and 137–162 GPa, respectively.