Indagine sulla corrosione di leghe di magnesio per impianti biomedici riassorbibili

The aim of this paper is to evaluate the mass loss rates of two magnesium and rare earth alloys, specifically WE43B and EV31A, in comparison with commercially pure magnesium. The growing interest for magnesium alloys in the field of bioabsorbable osteosynthesis devices is because they simultaneously fulfil the needs of biocompatibility and superior mechanical performance compared to biodegradable polymers. Weight loss tests were carried out for different exposure times in aerated isotonic solution (0.9% NaCl) at 37 °C. The results obtained showed excellent corrosion resistance of alloy WE43B compared to the other analyzed materials. Otherwise EV31A alloy exhibited numerous localized attacks, although showing lower weight loss than commercially pure magnesium. Alloy WE43B has a constant dissolution rate over the exposure time, whereas alloy EV31A and commercially pure magnesium exhibit a rate of corrosion that decreases over time due to the strong alkalinization of the solution and the deposition of a thick layer of corrosion products.