Abstract
The influences of Zn content and heat treatment on microstructure and corrosion behavior of Mg-xZn (x = 1 wt%, 3 wt%, 5 wt%, and 7 wt%) alloys were studied. (α-Mg+MgZn) eutectic cells and Zn-segregated regions were formed in the as-cast alloys. The Zn-rich phases acted as microcathodes in galvanic corrosion. Volume fraction of the Zn-rich phases increased with Zn content of the as-cast alloys, leading to a decrease in corrosion resistance. The corrosion rate of the as-cast alloys increased four times with an increase of the volume fraction of eutectic cell from 0.07 vol% of Mg-1Zn alloy to 2.18 vol% of Mg-5Zn alloy. The corrosion rate of Mg-7Zn alloy with 2.87 vol% eutectic cells was two times higher than that of Mg-5Zn alloy. The Zn-rich phases dissolved by the T4 treatment and only the T4-treated Mg-7Zn alloy obviously showed eutectic cells of 1.73 vol%. The polarization resistance (Rp) of the T4-treated Mg-1, 3, and 5Zn alloys was 2 to 10 times higher than that of the as-cast alloys. The T4-treated Mg-7Zn showed similar Rp to the as-cast Mg-5Zn alloy. Consequently, the volume fraction of Zn-rich phases dominated the corrosion resistance of Mg-xZn alloys.
| Original language | English |
|---|---|
| Pages (from-to) | 323-338 |
| Number of pages | 16 |
| Journal | Corrosion |
| Volume | 77 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 2021 Mar |
| Externally published | Yes |
Keywords
- bioresorbable
- localized corrosion
- magnesium
- passivation
- zinc
ASJC Scopus subject areas
- Chemistry(all)
- Chemical Engineering(all)
- Materials Science(all)