摘要
In the present study,to understand the mechanism of Mn on inhibiting Fe-caused Mg corrosion,the corrosion behaviour of commercial pure Mg and Mg-6 Mn alloy in 0.6 M NaCl solution is investigated.It is found that in Mg-6 Mn alloy,Fe impurity is incorporated into Mn to form Mn(Fe)phase with Fe as solid solute.The initial galvanic corrosion cannot be reduced through converting Fe-rich phase to Mn(Fe)phase,since Mn(Fe)phase also has relatively strong cathodic activity and has much larger volume fraction than Fe-rich phase.However,the cathodic activation behaviour of pure Mg is inhibited.The cathodic activity even decreases for Mg-Mn alloy with increased exposure time,due to the reduced cathodic HER at the Mn(Fe)particles.Mn can be oxidized at the OCP of Mg-6 Mn alloy,resulting in relatively dense Mn-rich corrosion film on particle surface,which separates the particle from the electrolyte and,consequently,inhibits HER.
基金
financial support by the National Nature Science Foundation of China(No.51601036 and U1737102)
the Fundamental Research Funds for the Central Universities(N170204010 and N162410002-2-4)
Young Elite Scientists Sponsorship Program by CAST(2017QNRC001)
