# Fileset

[Figures160510.pdf](https://mdr.nims.go.jp/filesets/622ffadc-8abb-4d3d-966c-a47602e87793/download)

## Creator

M. Bobby Kannan, Hadis Khakbaz, [A. Yamamoto](https://orcid.org/0000-0002-9182-4886)

## Rights

[Creative Commons BY-NC-ND Attribution-NonCommercial-NoDerivs 4.0 International](https://creativecommons.org/licenses/by-nc-nd/4.0/)

## Other metadata

[Understanding the influence of HEPES buffer concentration on the biodegradation of pure magnesium: An electrochemical study](https://mdr.nims.go.jp/datasets/0b43dd4a-4cd2-42e4-8c37-8ef3761d4b02)

## Fulltext

Fig 1. Molecular structure of 2-(4-(2-hydroxyethyl)-1-piperazinyl) ethanesulfonic acid (HEPES).                            Fig.2. Schematic of the electrochemical cell using in this study.  N N HO S OH O O Mg sample  Reference electrode (Ag/AgCl) Counter electrode (Pt mesh)  Stainless steel sheet (Electrical connectivity) Potentiostat/ Galvanostat Exposed Mg sample (0.95 cm2) Medium (10 ml)                    Fig 3. Nyquist plots of pure magnesium in different medium, and in the inset is the equivalent circuit used for modelling of impedance data. (Note: EBSS is denoted as E).      0 10000 20000 30000 400000500010000150002000025000300003500040000Z''(.cm2)Z'(.cm2) E E+CO2 E+HEPES25mM E+HEPES50mM E+HEPES100mM0 200 400 600 800 1000 1200-200020040060080010001200Z''(.cm2)Z'(.cm2)  Fig 4. Polarization resistance (Rp) of pure magnesium in different medium. (Note: EBSS is denoted as E)   110100100010000100000E+HEPES100mME+HEPES50mME+HEPES25mME+CO 2ERp (.cm2)   Fig. 5. Potentiodynamic curves of pure magnesium in different medium. (Note: EBSS is denoted as E).                        -9 -8 -7 -6 -5 -4 -3 -2-1.9-1.8-1.7-1.6-1.5-1.4-1.3-1.2-1.1Potential (VAg/AgCl)log i (A/cm2) E E+CO2 E+HEPES25mM E+HEPES50mM E+HEPES100mM                              Fig. 6. SEM micrographs of pure magnesium in EBSS and EBSS+CO2 medium. (Note: EBSS is denoted as E)                   1 mm E 100 um E 1 mm 100 um E+CO2 E+CO2                                                 Fig. 7. SEM micrographs of pure magnesium in EBSS with different HEPES concentrations. (Note: EBSS is denoted as E) 1 mm E+HEPES 100 mM 100 um E+HEPES 100 mM 1 mm E+HEPES 50 mM 100 um E+HEPES 50 mM 1 mm E+HEPES 25 mM 100 um E+HEPES 25 mM         Fig. 8. Degradation rate of pure magnesium in different medium. (Note: EBSS is denoted as E).        Fig. 9. Potential and pH data obtained before and after potentiodynamic polarization are mapped on the Potential-pH (Pourbaix) diagram of magnesium in aqueous solution. (Note: EBSS is abbreviated as E)  -3.2-2.8-2.4-2-1.6-1.2-0.8-0.400.40.8-2 0 2 4 6 8 10 12 14 16Potential (E), VpHMg          Mg2++2e- Degradation Immunity Passivation  Mg2++2OH-     Mg(OH)2 E E+CO2 E+HEPES 25MM E+HEPES 50MM E+HEPES 100MM  Initial pH         Final pH