Abstract Manganese-based coatings on AZ31 magnesium alloy with Mg(OH) 2 interlayer were prepared by hydrothermal reaction under different process conditions (temperature, time, and concentration). The harsh provided defects. These defects enabled the corrosive environment penetrated to which impaired corrosion properties of alloy. Optimal included a temperature 120 °C, 0.25 M MnCl , time 1 h. c...