Growth mechanism of hydroxyapatite-coatings formed on pure magnesium and corrosion behavior of the coated magnesium

► HAp coatings were formed on Mg surface by a hydrothermal treatment. ► At the initial stage of treatment, dome-shape HAp precipitates were formed. ► With an increase in the treatment time, the dome-shape precipitates formed layer. ► Protectiveness of the HAp coating increased with its growth.