localized corrosion

sc zr

intergranular corrosion

conversion coating

corrosion behavior

mg alloy

corrosion behaviour

plasma electrolytic oxidation

behavior mg

properties corrosion

Corrosion Science

Formation of profuse I 2 -type solute-enriched stacking faults (SESFs) in fine grains and transformation of SESFs to 18R-long period stacking ordered (LPSO) phase are attained in Mg-Er-Zn-Zr alloys. It is first confirmed by scanning Kelvin probe force microscopy (SKPFM) that SESFs with nanostructure act as weak anodes and the 18R-LPSO phase serves as cathode, which are verified by the theoretical calculated electronic work function and observation of scanning transmission electron microscope. Furthermore, the preferential corrosion of uniformly dispersed SESFs is demonstrated to be conducive to forming effective passivation film. It provides a new insight for developing high-strength and anti-corrosion Mg alloys. • The PD of weak anode SFs is measured at the nanoscale by SKPFM for the first time. • The reliability of SKPFM results is verified by the theoretical calculated WF. • Preferential corrosion of SFs is demonstrated using STEM-EDS for the first time. • Preferential corrosion of solute-enriched SFs is conducive to formation of passivation film. • A new insight for designing high-strength and anti-corrosion Mg alloys is proposed.

New insights on the different corrosion mechanisms of Mg alloys with solute-enriched stacking faults or long period stacking ordered phase