氟離子濃度對鎂鋰合金（LZ91）微弧陽極膜層影響之研究

Effects of Fluorine Ion Concentration to Micro-Arc Anodic Films on Magnesium Lithium Alloys

鎂鋰合金（LZ91）可藉由微弧陽極處理的方式，於試片表面上形成陶瓷氧化層，使基材提升抗蝕效能，本研究於於鍍液中添加不同濃度的氟化鈉，探討其氟離子濃度對陽極膜的影響，由電化學交流阻抗（EIS）分析中發現，陽極過程中添氟離子有助於陽極膜的抗蝕能力，但添加過高濃度的氟離子會使陽極膜的抗蝕性下降，於SEM觀察中發現當氟化鈉濃度超過15 g/L時陽極膜會形成樹枝狀的鬆散性多孔結構，而降低陽極膜的抗蝕性能。

In this research the advantage of micro-arc anodize forming ceramic oxide layer was taken to improve corrosion resistance of the magnesium lithium alloys. This study details the effect of sodium fluoride (NaF) concentration on the properties of anodic oxide films. Electrochemistry Impedance Spectroscopy (EIS) analysis discovers that adding more fluorine ion results in the coating having better corrosion resistance. The high fluorine ion concentration, however, will reduce corrosion resistance of the anodic films. When NaF concentration is over 15 gL-1, the coating formed comprised a porous dendrite microstructure in the oxide films and will reduce its corrosion resistance.