Fig. 1 XRD patterns of the anodized magnesium alloy and hydrophobic coatings obtained at the different working voltages

Fig. 2 Current density as a function of time recorded during the electrodeposition process. The insets are the SEM images of the coatings formed under 50 V at 1 min a, 7 min b

Fig. 3 Surface morphologies of the anodized magnesium alloy a and coatings formed at the different voltages (b 20 V, c 50 V, d 100 V). The insets in b, c, d show images at high magnification, respectively

Fig. 4 3D observations and 2D roughness parameters of the coatings obtained at the different working voltages: a 20 V, b 50 V, c 100 V. The insets are static contact angle of water droplet on the surface of the coatings, respectively

Fig. 5 Cross-sectional images of coatings formed at the different working voltages: a 20 V, b 50 V, c 100 V

Fig. 6 Polarization curves of the anodized magnesium alloy and hydrophobic coatings formed at the different working voltages in SBF at 37?±?0.5 °C

Fig. 7 Bode plot evolution of the coated substrates (a HC-20, b HC-50, c HC-100) and the anodized magnesium alloy d in SBF at 37?±? 0.5 °C. Symbols are experimental data and solid lines are fitting data

Fig. 8 Equivalent circuit models for the impedance spectra of the coated samples and anodized magnesium alloy substrate immersion in SBF at 37?±?0.5 °C during the different periods: a 0 h, 6 h, and 12 h for HC-50; b 0-24 h for HC-20, 24-96 h for HC-50, and 0-96 h for HC-100; c 48-96 h for HC-20 and 0-12 h for the anodized magnesium alloy

Fig. 9 EIS fitting parameters for the coated samples and anodized magnesium alloy in SBF at 37?±? 0.5 °C: aRcoat, bRano, cRct