Effects of Nitrogen and Hydrogen Plasma Treatments on a Mg-2Y-1Zn-1Mn Resorbable Alloy

Mg alloys have recently been investigated and optimized for the development of biodegradable implants for orthopedic, dental, vascular, and other applications. However, their rapid degradation in a physiological environment remains the main obstacle to their development. In this work, the effects of nitrogen and hydrogen plasma treatments on the surface properties and corrosion behavior of an Mg-2Y-1Zn-1Mn (WZM211) alloy were investigated. Plasma treatment effectively modified the surface of a WZM211 alloy by removing the original oxide layer, followed by the formation of a new surface layer with controlled composition, thickness, and wettability. The water contact angle decreased from 100° to 17° after nitrogen plasma and to 45° after hydrogen plasma treatment. The nitrogen plasma treatment, shortly N-Plasma, resulted in the lowest corrosion rate (CR_N = 0.038 ± 0.010 mm/y) if compared with the hydrogen plasma treatment, shortly H-Plasma (CR_H = 0.044 ± 0.003 mm/y) and untreated samples (0.233 ± 0.097 mm/y). The results demonstrate the potential of nitrogen and hydrogen plasma treatment for the development of resorbable Mg-based implants.