Evaluation of corrosion resistance of biocompatible coatings on magnesium

The work deals with the study of innovative biocompatible coatings for magnesium resorbable osteosynthesisdevices. Conversion layers based on magnesium fl uoride and “diamond like carbon” coatings (DLC) obtainedby chemical vapor deposition were considered in order to reduce the corrosion rate of magnesium to levelscompatible with the time needed for fracture healing. DLC coating was applied on both pure magnesiumand on magnesium after conversion treatment in hydrofl uoric acid. Weight loss tests and potentiodynamicpolarization tests in aerated Hank’s solution at room temperature were performed. The corrosion rate wasabout 100 mg/cm2day for the commercially pure magnesium (99.9 %) in the fi rst 24 hours of exposure. Boththe coatings reduced the short-term corrosion rate but the protective layers did not grant long-term stabilityand corrosion rate rapidly increases approaching the values of uncoated magnesium