A special composite hydroxyapatite (HA) arrays were prepared by Nafion-assisted electrodeposition on Ni foams. The effect of Nafion template on the morphology and crystallinity of the coating were studied. It was shown that the coating consisted predominantly of stoichiometric HA phase and the crystallinity can be enhanced by Nafion, from 85.27% to 91.57%. Moreover, for the pure Ni foams, the HA arrays are uniformly strip-like. While for those Ni foams coated with Nafion, a composite HA array structures with strip-like crystals and microspheres were generated, which are considered to be promising for applications in sensors. The mechanism of different HA structures forming on different foams was discussed. �� 2013 Elsevier B.V.