Fig. 1 Process of fabricating Zn-Mn alloy foam

Fig. 2 A, B Macro and micro morphologies of pure Zn and Zn-Mn alloy foams prepared under different conditions; C EDS mapping of Zn-Mn alloy foam; D alloy foam after heat treatment; E X-ray diffraction patterns

Fig. 3 Important parameters of pure Zn and Zn-Mn alloy foams. A Deposition efficiency and porosity histograms: a deposition current group, the other parameters were pH = 4, T = 30 °C, b electrolyte pH group, the other parameters were I = 0.4 A, T = 30 °C, c electrolyte temperature group, the other parameters were I = 0.4 A, pH = 4, and d pure Zn and Zn-Mn alloy foams, the parameters were I = 0.4 A, pH = 4 and T = 30 °C. B Pore size and pore wall thickness histograms: a deposition current group, the other parameters were pH = 4, T = 30 °C, b electrolyte pH group, the other parameters were I = 0.4 A, T = 30 °C, c electrolyte temperature group, the other parameters were I = 0.4 A, pH = 4, and d pure Zn and Zn-Mn alloy foams, the parameters were I = 0.4 A, pH = 4 and T = 30 °C

Fig. 4 Mechanical properties of pure Zn and Zn-Mn alloy foams. A Compressive stress-strain curves: a deposition current group, b electrolyte pH group, c electrolyte temperature group, and d pure Zn and Zn-Mn alloy foams, the parameters were I = 0.4 A, pH = 4 and T = 30 °C. B Peak stress histograms: a deposition current group, b electrolyte pH group, c electrolyte temperature group, and d pure Zn and Zn-Mn alloy foams, the parameters were I = 0.4 A, pH = 4 and T = 30 °C

Fig. 5 Immersion test results of pure Zn and Zn-Mn alloy foams. A Rate of weight loss curves: a deposition current group, b electrolyte pH group, c electrolyte temperature group, and d pure Zn and Zn-Mn alloy foams, the parameters were I = 0.4 A, pH = 4 and T = 30 °C. B Corrosion rate histograms: a deposition current group, b electrolyte pH group, c electrolyte temperature group, and d pure Zn and Zn-Mn alloy foams, the parameters were I = 0.4 A, pH = 4 and T = 30 °C. C Surface macroscopic morphologies of the foams after immersing in r-SBF for different times. D Surface SEM images of the foams after the immersion for different times: a pure Zn metal foams, b Zn-Mn alloy foams

Fig. 6 Live/dead fluorescence staining images and MTT results of MC3T3-E1 cells cultured for 1, 3 and 5 days in osteogenic medium containing 10% foam extracts. A Deposition current group, B electrolyte pH group, C electrolyte temperature group, and D pure Zn and Zn-Mn alloy foams. (** p < 0.01 and *** p < 0.001)

Fig. 7 Ion concentration histograms of the foam extracts: A deposition current group, the other parameters were pH = 4, T = 30 °C; B electrolyte pH group, the other parameters were I = 0.4 A, T = 30 °C; C electrolyte temperature group, the other parameters were I = 0.4 A, pH = 4; D pure Zn and Zn-Mn alloy foams, the parameters were I = 0.4 A, pH = 4 and T = 30 °C

Fig. 8 Optical images of ALP activity of MC3T3-E1 cells cultured in osteogenic medium containing 10% foam extract for 3 and 7 days: A deposition current group; B electrolyte pH group; C electrolyte temperature group; D pure Zn and Zn-Mn alloy foams

Fig. 9 Qualitative images and Quantitative results of type I collagen secreted of MC3T3-E1 cells cultured for 7 and 14 days in osteogenic medium containing 10% foam extracts: A deposition current group, B electrolyte pH group, C electrolyte temperature group, and D pure Zn and Zn-Mn alloy foams. (** p < 0.01 and *** p < 0.001)

Fig. 10 Qualitative images and Quantitative results of extracellular matrix mineralization of MC3T3-E1 cells cultured for 14 and 21 days in osteogenic medium containing 10% foam extracts: A deposition current group, B electrolyte pH group, C electrolyte temperature group, and D pure Zn and Zn-Mn alloy foams. (** p < 0.01 and *** p < 0.001)