本研究中藉由電化學沉積法成功的於AlCl3-EMIC離子液體為基底鍍液，在面積4平方公分的鎂合金製備具有附著性與耐蝕性的鋁鍍層。前處理、添加劑、析鍍電位對鋁鍍層之性質影響，在本文中皆加以探討。在各種不同條件下所製備之鍍層，利用掃描式電子顯微鏡(SEM)觀察鍍層的表面形貌，以橫截面分析鋁鍍層的厚度與附著性。鍍層之化學組成則藉由能量散佈分析儀(EDS)量測，其晶體結構則以X光繞射儀(XRD)進行分析。在電化學測試方面，選擇在3.5 wt% 氯化鈉水溶液進行開路電位、動電位極化曲線及交流阻抗頻譜量測。
實驗結果顯示，利用研磨處理無法得到具附著性的鋁鍍層，無法有效去除鎂合金基材表面的氧化層，藉由鎂合金基材在離子液體鍍液內，以+1.5 VAl陽極溶解三分鐘，鎂合金基材表面氧化層與鍍液反應，逐漸溶解至鍍液內，達到移除氧化層的目的，得到適合電鍍的鎂合金表面，經電鍍鋁後得到具附著性的鋁鍍層，顯示陽極溶解為有效地前處理。
鎂合金基材於AlCl3-EMIC離子液體內，經過陽極溶解前處理再析鍍鋁的鍍層，結晶物形貌為板狀，沉積的優選方位為(111)面，隨析鍍電位提高，結晶物尺寸變更細小，提高鍍層厚度均勻性與減少內部針孔。鎂合金基材於添加菸鹼酸的離子液體內，經過陽極溶解前處理再析鍍鋁的鍍層，結晶物為顆粒狀，沉積的優選方位為(200)面，菸鹼酸的羧酸為拉電子基，使吡啶的氮原子的電子密度下降，電鍍時，陰極表面會吸附陽離子，菸鹼酸由於本身所帶電荷與電場作用，吸附於陰極表面影響鋁沉積，使結晶物形貌由板狀便顆粒狀，消除鍍層內針孔，得到厚度均勻的鍍層，因此菸鹼酸為具有整平劑的作用。
在3.5 wt% 氯化鈉水溶液中，以AlCl3-EMIC離子液體為鍍液，鋁鍍層在陽極區域溶解速率隨析鍍電位提高有較慢趨勢，代表鋁鍍層展現保護性，但因為鍍層內部充滿孔隙，提供氯化鈉水溶液滲透到鎂基材通路，鎂基材遭受腐蝕，溶解至氯化鈉水溶液。電化學交流阻抗測試，鋁鍍層阻抗值小於基材，顯示鋁鍍層無法抵抗腐蝕因子，使水溶液可與新鮮鎂合金金基材反應，造成阻抗值未提升。以添加菸鹼酸之AlCl3-EMIC離子液體為鍍液，鋁鍍層之開路電位維持穩定，在陽極區域出現鈍化區，顯示在相同電位環境下，可以有效降低腐蝕速率。電化學交流阻抗測試，隨析鍍電位提高，鍍層阻抗也提高，顯示當析鍍電位較大時，鋁鍍層耐蝕性質最佳。

Al coating on magnesium (Mg) alloy with a large dimension of surface area was attempted by employing ionic liquid electrodeposition. The electrolyte used was AlCl3-EMIC ionic liquid with a molar ratio of 2:1. The effects of surface pretreatment, nicotinic acid addition and electrodeposition potential on the properties of Al coating were focused. The surface morphology of Al coating was examined by a scanning electron microscope (SEM), while its crystal structure was analyzed by X-ray diffraction. The corrosion performances of the Mg alloy with and without Al coating were evaluated by conducting various electrochemical measurements in 3.5 wt% NaCl solution. The experimental results showed that anodic polarization prior to electrodeposition was beneficial in improving the adhesion of Al coating on the Mg alloy substrate. The addition of nicotinic acid into the ionic liquid electrolyte further modifying the surface roughness of the coating. The results of potentiodynamic polarization tests in 3.5 wt% NaCl solution showed that the corrosion resistance of the Mg alloy studied could be substantially improved by Al coating. The passivation behavior of Al coating depended on the electrodeposition potential applied. A maximum polarization resistance of 86500 Ω-cm2 was determined by electrochemical impedance spectroscopy (EIS), which was about two order of magnitude higher than that of the bare Mg alloy studied.

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