Corrosion behavior of commercially pure Mg and ZM21 Mg alloy in Ringer’s solution – Long term evaluation by EIS

Evaluation of the corrosion behavior of commercially pure magnesium (CP-Mg) and ZM21 Mg alloy immersed in Ringer’s solution for 92 h by electrochemical impedance spectroscopy (EIS) is addressed. The formation of a compact layer of well-developed rod-like aragonitic CaCO3 crystals and its subsequent thickening with increase in immersion time offers a higher corrosion protective ability for ZM21 Mg alloy. The formation of a mud-crack pattern and a large number of clusters of needle-like crystals offers a relatively lower corrosion resistance for CP-Mg. The study suggests that ZM21 Mg alloy is a promising candidate material for the development of degradable implants.

Research highlights
► ZM21 Mg alloy offers a higher corrosion resistance than CP Mg.
► Mg(OH)2 and aragonitic CaCO3 are the corrosion products on CP-Mg and ZM21 Mg alloy.
► Thickening of the corrosion product layer is delayed in CP Mg.
► ZM21 Mg alloy is a promising candidate for degradable implant.