本研究利用純度99.99%之鋁片，在低溫下進行二次陽極氧化處理後，可製得高孔隙率、規則分布以及均一奈米孔洞的陽極氧化鋁(Anodic Aluminum Oxide；AAO)薄膜，而陽極處理使用三種不同類型的電解液(硫酸、草酸及磷酸)製備AAO並且探討其機械性質與摩擦學行為。藉由調整電解液類型，以製備平均孔徑為20~270nm以及孔隙率為18%~41%之AAO模板；進而使用奈米壓痕機測得其機械性質，其中包括硬度值和摩擦係數。在硫酸系統中製備之AAO再經由奈米壓痕機測試，其施加之荷重分別為1000μN、5500μN、10000μN，為了使硬度測試之結果呈再現性，本實驗從1000μN以遞增荷重方式到10000μN，所獲得之負載-位移(P-D)曲線會隨施加之荷重越大，受表面粗糙度影響越小。原始之硫酸樣品與擴孔10及20分鐘後之硫酸樣品經測試後，其結果均顯示硬度會隨施加之荷重增加而增加，由微觀結構可推測當多孔性結構受到正向力(Normal force)往下擠壓，會導致筆直之孔壁崩塌，然而層層堆疊使材料局部結構密度上升，使其硬度值升高；若是使用固定之荷重分析硫酸系統之AAO，經擴孔處理後之AAO結構相對鬆散，獲得之硬度會隨擴孔時間增加而下降，而封孔處理後表面會覆蓋一層鱗片狀薄膜，導致其硬度降低，因此使用維克氏硬度機測試，結果顯示AAO封孔比擴孔後之硬度較高，表示以傳統之硬度測試方可得到硬度會隨孔洞越小而上升之趨勢。另外，在刮痕測試的部分，將硫酸系統之AAO經過擴孔與封孔處理後，皆以10000μN正向力進行單一軸向的刮痕測試，結果顯示摩擦係數會隨著孔徑增加而增大，表示當孔徑越大探針下針會越深，使探針移動的阻力增加，導致摩擦係數增大。最後，比較三種酸性電解液之陽極處理結果，結果指出，孔隙率以磷酸電解液最大，草酸電解液其次，硫酸電解液最低；由於大孔徑之結構較鬆散，使硬度隨著孔隙率增加而下降，而本實驗中草酸系統之硬度卻比硫酸系統高，是由於草酸系統製備之AAO表面存在應力殘留之缺陷，導致其硬度比其他兩者還高。不管是硬度還是摩擦係數，本實驗的結果趨勢與緻密薄膜有所差異，因此將可以代表多孔性結構獨特之機械性質。

In this study, an aluminum foil with purity 99.99% was used to conduct anodizing at 5℃ to obtain anodic aluminum oxide(AAO) films which have high porosity, and regular pore size distribution. In order to study mechanical properties and tribological behavior of AAO, it was manufactured in different electrolytes including sulfuric acid, oxalic acid and phosphoric acid, providing adjustable pore size (20nm ~ 270nm) and porosity (18% ~ 41%). Additionally, the AAO was manufactured by the sulfuric acid through widening and sealing treatment. The hardness and friction coefficient of AAOs were investigated by nanoindentation with normal forces 1000μN, 5500μN, and 10000μN, respectively. The results show that hardness increases with the applied loads because porous structure is pressed down by the normal force, which leads the straight pore wall to collapse, and makes the structure density increase partly. After AAO films were sealed, they were covered with a layer of scaly film, which caused the hardness of AAO to decrease. Therefore, the result showed that the hardness of AAO sealed for two hours was the highest via Vickers-hardness test. The consequent indicated that the hardness increased as the sealing time raised. According to the result of scratch test, the larger the pore size, the higher the coefficient of friction. Finally, in the literatures, the hardness decreased as the porosity increased generally, but the results indicate that AAO with the highest hardness was obtained in oxalic acid system, not sulfuric acid system. The reason is that residual stresses and defects exist in AAO surface, resulting in nonuniform pores. The mechanical properties of AAO found in our study show the unique features for porous structures.

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