Abstract
The effect of Er-rich precipitates on microstructure and electrochemical behavior of the Al–Zn–In anode alloy is investigated. The results showed that with the increase in Er content, the microstructure was refined, the amount of interdendritic precipitates gradually increased, and the morphology changed from discontinuous to continuous network gradually. With the addition of Er element, the self-corrosion potential of the Al–5Zn–0.03In–xEr alloy moved positively, the self-corrosion current density decreased, and the corrosion resistance increased. When the Er content was less than 1 wt.%, the addition of Er improved the dissolution state of the Al–5Zn–0.03In–xEr alloy, and increased the current efficiency of the Al–5Zn–0.03In–xEr alloy. When the Er content was more than 1 wt.%, the current efficiency was reduced. The major precipitate of the alloy was Al3Er. According to the element composition of Al3Er in the Al–Zn–In–Er alloy, the simulated-segregated-phase alloy was melted to explain the effect of Al3Er segregation on the electrochemical behavior of alloys, and the polarization curve and AC impedance spectrum of the simulated-segregated-phase alloy and the Al–Zn–In alloy were measured. The results showed that Al3Er was an anodic segregation phase in the Al–Zn–In–Er alloy, and the preferential dissolution of the segregation phase would occur in the alloy, but the Al3Er phase itself was passivated in the dissolution process, which inhibited the further activation of the dissolution reaction of the Al–Zn–In–Er alloy to a certain extent.
Highlights
The sacrificial anode protection method is a relatively mature electrochemical protection method, which has the advantages of simple equipment, convenient installation, low maintenance difficulty, long service life, low cost, and so on
The microstructure of the alloy was observed by a Leica DM2700P polarized light microscope (Leica, Weltzar, Germany), and the distribution and morphology of the segregation phase were observed by Hitachi SU8220 scanning electron microscope (Hitachi, Tokyo, Japan)
In order to test the polarization curve, the Luggin capillary should be as close to the surface of the working electrode as possible to reduce the influence on the solution resistance
Summary
The sacrificial anode protection method is a relatively mature electrochemical protection method, which has the advantages of simple equipment, convenient installation, low maintenance difficulty, long service life, low cost, and so on. Adding rare earth elements to aluminum alloys can effectively improve the microstructure and comprehensive properties of the alloys [14,15,16,17,18,19,20]. N.Q. et al [19] found that using 0.005 at% Er instead of the more expensive Sc can maintain higher room temperature strength and significantly improve high temperature creep resistance when studying the effect of Si, Zr, and Er microalloying on the Al–Sc alloy Xinwei She [25] studied the effect of Er on the microstructure and properties of aluminum alloy with a large width thickness ratio. 0.03In–xEr alloy with an Er content of 0.5 wt.%, 1 wt.%, and 4 wt.% were prepared to study the effects of Er content and Al3 Er precipitates on the microstructure and electrochemical properties of the alloy
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
