CORROSION PROTECTION OF MAGNESIUM ALLOY AZ31 VIA PHOSPHONIUM BASED IONIC LIQUIDS

摘要

Magnesium alloys are becoming important materials for infrastructure, automotive, aerospace, and energy storage applications, [2] however, the use of magnesium based alloys is not yet widespread because of poor corrosion resistance. To address the poor corrosion resistance of pure Mg and its alloys, conversion coatings are typically used to provide corrosion protection. In this project, three phosphonium based ionic liquids have been synthesized and tested as environmentally friendly alternatives to chromate based treatments. Both electrochemical and immersion testing results confirmed that Trihexyl(tetradecyl) phosphonium Diphenyl Phosphate (P_(6,6,6,14)DPP) and Trimethyl Butyl phosphonium Diphenyl Phosphate (P_(1,4,4,4)DPP) ionic liquids protected the magnesium alloy against the corrosion attack. On the other hand, Trimethyl Butyl ammonium Diphenyl Phosphate (N_(1,4,4,4)DPP) ionic liquid appeared to enhance the corrosion process.