Flow-induced corrosion behavior of absorbable magnesium-based stents

Area of Science:

• Biomaterials Science
• Corrosion Engineering
• Cardiovascular Device Technology

Background:

• Absorbable magnesium-based stents offer promising alternatives to permanent metallic stents.
• The vascular environment presents unique challenges, including complex fluid dynamics.
• Understanding corrosion behavior is critical for the long-term performance and safety of magnesium stents.

Purpose of the Study:

• To investigate the corrosion behavior of magnesium alloys (MgZnCa plates and AZ31 stents) under simulated vascular fluid flow conditions.
• To elucidate the role of fluid hydrodynamics, velocity, and shear stress on magnesium alloy corrosion.
• To quantify the effects of flow-induced shear stress (FISS) on various corrosion mechanisms.

Main Methods:

• Experimental study of MgZnCa plates and AZ31 stents under varied fluid flow conditions.
• Analysis of corrosion rates, localized corrosion, pitting, and erosion under different shear stress levels.
• Evaluation of the impact of flow direction on corrosion product layer integrity and material loss.

Main Results:

• Fluid flow, velocity, and shear stress significantly influence the corrosion of magnesium-based stents.
• Flow-induced shear stress (FISS) accelerates uniform, localized, pitting, and erosion corrosion by enhancing mass transfer and mechanical forces.
• FISS increased corrosion rates, localized corrosion severity, and material removal, with flow direction impacting localized attack and corrosion product detachment.

Conclusions:

• Flow-induced corrosion is a critical factor in the degradation of magnesium-based vascular stents.
• Understanding and mitigating FISS is essential for optimizing the design and performance of these devices.
• Further research into flow-corrosion interactions will enable the development of more reliable and effective absorbable magnesium stents.