Effects of Radio-Frequency Currents on the Corrosion Behavior of the WE43 Mg Alloy in a Simulated Intestinal Environment.

Magnesium (Mg) alloys are promising biodegradable implants due to their biocompatibility, favorable mechanical properties, and intrinsic degradability. Their good electrical conductivity also makes Mg alloys attractive as biodegradable electrodes for radio frequency (RF) intestinal tissue welding. However, the corrosion behavior of Mg alloys in the presence of an RF current in the physiological environment is not well understood. Herein, the influence of RF currents on the corrosion properties of the WE43 alloy is investigated in the simulated intestinal fluid (SIF). After being subjected to an RF current for 0, 8, 30, 60, and 120 s, the corrosion properties of the samples are evaluated by immersion, microstructural, and electrochemical measurements. The RF current markedly accelerates the corrosion of WE43, and after 120 s, the corrosion rate rises by ∼50% (7.33 ± 0.36 mm·y-1-11.01 ± 0.34 mm·y-1), in addition to a higher current density and lower polarization resistance. Microstructural examination reveals intense local corrosion and early chloride attack. The results suggest that the RF current disrupts the surface passivation film and accelerates the degradation of the WE43 Mg alloy. The results provide insights into the design of Mg implants with controlled degradation and proper temporary mechanical support during healing as well as timely dissolution.