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The Corrosion Behavior of Amorphous / Nanocrystalline Alloys in Various Aggressive Aqueous Solutions
|Authors: ||Yun-Fang Wu|
|Contributors: ||NTOU:Institute of Materials Engineering|
|Issue Date: ||2011-06-30T07:22:43Z
|Abstract: ||本研究目的在探討鈀基、鐵基與鋯基非晶質合金及其奈米結晶之相變化情形及其在各種腐蝕性水溶液中之抗腐蝕性質。結果顯示出非晶質合金若經由適當的真空退火熱處理後，均能形成奈米尺寸的結晶。其中，奈米化後的Pd40Ni40P20塊狀非晶質合金，在各種腐蝕性環境下之抗腐蝕性質均得以提升且沒有發生孔蝕的現象。而Fe40Ni38B18Mo4、Fe78B13Si9、Fe79B16Si5與Fe81B13.5Si3.5C2非晶質薄帶合金在3.5% NaCl水溶液環境下，除了Fe40Ni38B18Mo4非晶質薄帶合金由於其奈米結晶化後之表面會發生微伽凡尼效應，使其腐蝕速率增加，其他鐵基非晶質薄帶合金在奈米化後之抗腐蝕性質均優於其非晶質態合金，且隨著硼含量的增加，鐵基非晶質薄帶合金的腐蝕速率會有下降的趨勢，且均沒有孔蝕現象的發生。Ｚr-Al-Ni基塊狀非晶質合金中，在各種腐環境下的抗腐蝕性質與抗孔蝕性質均優於其結晶化後之結晶態合金。|
Abstract The purpose of these studies is to investigate the corrosion behaviors of Pd-based, Fe-based, and Zr-based amorphous alloys and their crystalline states in different aqueous solutions at room temperature. The results show that the nanocrystalline states of these amorphous alloys can be obtained by suitable vacuum annealing. For Pd40Ni40P20 in various aqueous solutions, the corrosion resistance of its nanocrystalline state is better than that of its amorphous state due to its nanocrystalline state mainly consists of inert and noble phases. These inert and noble properties result in a higher corrosion resistance (lower corrosion rate) in nanocrystalline Pd40Ni40P20. For F40Ni38B18Mo4 in 3.5% NaCl solution, the corrosion resistance of its nanocrystalline state shows inferior to its amorphous state due to the local micro-galvanic cell action between different crystalline phase in matrix; whereas for Fe78B13Si9, Fe79B16Si5, and Fe81B13.5Si3.5C2 in 3.5% NaCl solution, the corrosion resistance of their amorphous states show inferior to their nanocrystalline states, and there is a tendency to increase the corrosion rate when increasing the Si content of their amorphous states. For Zr-Al-Ni based alloys in various aqueous solutions, the corrosion resistance of their amorphous state is better than that of their nanocrystalline state, and there is a tendency to increase the corrosion rate when increasing the Al content of their nanocrystalline states.
|Appears in Collections:||[材料工程研究所] 博碩士論文|
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