Effect of the Content and Morphology of β-Compounds and Precipitation on the Corrosion Behavior of Biodegradable Magnesium Alloys

Authors：Gui, Zhenzhen; Kang, Zhixin; Zhou, Yan^*; Zhang, Jianhui

Source：ADVANCED ENGINEERING MATERIALS, 2021, 23(1): 2000752.

DOI：10.1002/adem.202000752

• biodegradable magnesium
• corrosion behavior
• microgalvanic corrosion
• precipitation
• beta-compounds

Microstructure analyses, immersion tests, and electrochemical measurements are performed to investigate the corrosion behavior of Mg-1.59Nd-2.91-Zn-0.05Zr-0.35Mn (NZKM) alloy under three different conditions (as-cast, heat-treated, and as-extruded) in Hanks' solution. The results indicate that the corrosion rates of the three types of NZKM alloys are all lower than 0.5 mm year(-1). The primary driving force of the NZKM alloys' corrosion is the microgalvanic coupling between alpha-Mg and beta-compounds/precipitates in Hanks' solution during the corrosion process. The lowest corrosion rates can be attributed to a low content of beta-compounds and less precipitation, a necklace-type appearance, and discontinuous distribution of the beta-compounds in the heat-treated NZKM alloy. The clustered precipitation that occurs within the as-extruded NZKM exacerbates the corrosion process due to the formation of clustered microgalvanic couple groups. These results indicate that the content of beta-compounds and precipitation of the NZKM alloys, as well as their appearances and distributions, should be controlled to allow for further application as biodegradable materials.

• Institution
  y; 广州大学