本論文是在研究高熵合金AlCrFeMnNi的電化學性質，並添加Mo(鉬)形成5種6成份AlxMo1-xFeCrNiMn。實驗使用市售硫酸、氯化鈉、硫酸鈉配製成不同濃度的硫酸及氯化鈉溶液後，並以恆電位儀測量此五種合金在溶液中的陽極極化曲線，並決定其腐蝕電位、臨界電流、鈍態電流、孔蝕電位及腐蝕速率等電化學數據。另外並以PH~7之不同濃度的硫酸鈉/氯化鈉混合溶液，觀察在常溫下混合溶液隨著氯離子的增加前後對於電化學孔蝕電位造成的影響。
五種高熵合金來說，在Al的量為0、0.3、0.5莫耳時，XRD繞射圖顯示在35゜到55゜中增加許多繞射峰，且在硬度測試中這三種合金都有超過600Hv的水準，又以Al0.5Mo0.5-這一個平均硬度739.62，是五種合金內最硬，推測許多Mo與其他四個元素(Fe、Cr、Ni、Mn)的介金屬化合物在合金中提升硬度，在Al的量為0.5及1莫耳時，繞射圖所顯現的是BCC的特徵峰，所以我們推測Al的量越多會驅使，的幫助下繞射圖的複雜度與合金本身的硬度增加，鋁的添加量越多會使晶格結構趨向BCC結構。在電化學測試中在0.1M硫酸屬於均勻腐蝕，在測試當中以Al0Mo1-之高熵合金擁有最低的臨界腐蝕電流密度表現最佳，利用溫度效應量測求得高熵合金在硫酸中的活化能。其活化能的高低關係與其在溶液中之電化學表現；在0.1M的氯化鈉溶液中，五種高熵合金表現差異不大，在-0.05-0.23 V(SHE)測得孔蝕電位(Epit)。但在氯化鈉溶液中，以添加少量Mo的Al0.7Mo0.3-及Al0.5Mo0.5-的表現較好，尤其是含Mo量較低的Al0.7Mo0.3-，本研究發現少量Mo的添加確實有助於防止氯離子的侵蝕。
混合溶液實驗方面，可觀察到隨著氯離子的減少，可以降低孔蝕發生的機會，由此可知氯離子對高熵合金的孔蝕扮演重要的角色。當鋁含量增加，合金在陽極極化的鈍態區間隨著變寬，鉬的含量增加明顯讓合金減緩其在含氯鹽溶液中的影響。
The thesis studied the electrochemical property on the high entropy alloys AlCrFeMnNi, and we synthetized five kinds of the high entropy alloys (AlxMo11-xFeCrNiMn) when we added Mo. In the study，we used sulfuric acid，sodium chloride and sodium sulfate；In addition, the polarization curves of these five alloys in sulfuric acid solutions or sodium chloride solutions with different temperature were also tested for measuring their corrosion potentials and corrosion currents. In addition, we could observe the electrochemical properties of (AlxMoyFeCrNiMn， x+y=1，) in the room temperature with changing [Cl-] in different concentrations mixed solutions of sulfuric acid/ sodium chloride or sodium chloride/ sodium sulfate.
In this study we found Al0.3Mo0.7FeCrNiMn is the hardest when amount of aluminum added difference. We guess there were lots of intermetallic compounds in the alloys. Al1Mo0FeCrNiMn & Al0.7Mo0.3FeCrNiMn is BCC structure, but we could not easily found the other three alloys.
Al0Mo1FeCrNiMn is better than another of five in sulfuric acid solution with the same concentration；the five high entropy alloys’ electrochemical properties are near in the 0.1M sodium chloride solutions, but in the 0.05M sodium chloride and sodium chloride / sodium sulfate solutions Al0.7Mo0.3FeCrNiMn is the the best. In 0.1M sulfuric acid in difference temperature to use Arrhenius plot we found the activation energy of Al0.3Mo0.5FeCrNiMn is the highest . Al0.7Mo0.3FeCrNiMn ,it proved that adding lower Mo has better corrosion resistance. But five of AlxMo1-xFeCrNiMn were not good in corrosion resistance. In mixed solutions studying ,we could know [Cl-] is directly proportional to pitting, and [Cl-] is a important role to pit.
