Corrosion rate modelling of biodegradable porous iron scaffold considering the effect of porosity and pore morphology.

Porous iron (Fe) has shown promising capabilities to be used as biodegradable material. However, to achieve the desired rate of degradation in porous Fe, there exists a need to develop a model explaining the effect of variation in morphology of the porous structure on the corrosion rate. Hence, in the present study, an empirical model for the prediction of the corrosion rate of porous Fe scaffold samples possessing different levels of porosity and pore morphology has been developed. To develop the model, Fe scaffold samples having random porous microporous structure and designed topologically ordered porous structures were fabricated using 3D printing and pressureless microwave sintering. Potentiodynamic polarization tests were performed to assess the corrosion properties of fabricated porous Fe scaffold samples in simulated body fluid solution at 37 °C. It was found that with an increase in random microporosity and the reduction in the size of the designed macropores, an increase in corrosion rate was obtained. Mathematical relationships between governing factors affecting corrosion rate (i.e. corrosion current and exposed surface area) and porosity were deduced. The developed model was validated with the experimental results and good agreement of predicted values with the experimental values was obtained with a maximum error of 6.97%.