Electrodeposition Of Biodegradable Fe-Zn Alloy In Deep Eutectic Solvent

The main problem faced by Fe as a degradable scaffold material is that the degradation rate is too slow.Alloying is a better means to improve the degradation rate of Fe.Zn standard electrode potential is lower than Fe and has good biocompatibility.Alloying iron with Zn as the second component is expected to improve the corrosion degradation rate of iron.However,the boiling point difference between pure Fe and pure Zn is too large,so our research group innovatively proposes to use electrodeposition to prepare Fe-Zn alloy to solve the problem of large boiling point difference and difficult mutual solubility at room temperature.However,the previous electrodeposition work in our laboratory used electrolyte solution with water as the solvent.The electrochemical window of water is narrow,and side reactions are easy to occur in the electrodeposition process.Low eutectic solvent is a new electrolyte solvent with good performance.Therefore,the main purpose of this experiment is to explore whether iron zinc alloy can be co deposited with low eutectic solvent as the base solution,and try to find the appropriate electrodeposition parameters.The main research work is as follows:through cyclic voltammetry and chrono-amperometry to explore the reduction behavior and nucleation behavior of iron and zinc ions in eutectic solvent,explore their reduction and nucleation mechanism,find out the appropriate deposition conditions of Fe-Zn in eutectic solvent,and electrodeposit Fe-Zn alloy.The phase,composition and micro morphology of the deposited coating were characterized by XRD,EPMA and SEM.Tafel polarization curve was used to study whether the corrosion degradation rate of the coating was improved compared with that of Fe;Fe-Zn alloy was electrodeposited by different electrodeposition methods,and its properties were characterized.The results show that both iron and zinc ions are reduced and oxidized in one step in eutectic solvent.The optimal concentration ratio of iron and zinc ions in DES is 2:1,and the optimal temperature for electrodeposition is 80℃.They are co deposited in low eutectic solvent,and their nucleation mechanism is three-dimensional progressive nucleation.The results of alloy composition analysis show that the coatings obtained by different deposition methods contain Fe,Zn and O.the weight percentage of Zn increases with the negative shift of deposition potential or the increase of current density,and decreases with the increase of pulse frequency.The XRD diffraction peaks of the coatings obtained by different deposition methods areα-Fe The diffraction peak of Fe and Fe-Zn equilibrium phase diagram show that the alloy formed by electrodeposition in low eutectic solvent is a supersaturated solid solution of Fe.The results of polarization curves show that the corrosion degradation rate of Fe-Zn alloy is higher than that of pure Fe,but the corrosion degradation rate of Fe-Zn alloy first increases and then decreases with the increase of Zn content in the coating.The maximum corrosion current density of Fe-Zn with a deposition potential of 2 m A·cm^-2（4.0%Zn）is 15.5μA·cm^–2,7.3 times that of pure iron.The results show that the eutectic solvent has potential in the electrodeposition of Fe-Zn alloy.