鋁及鋁合金質輕且易加工，可以製成非常複雜的零件，因而在工業上的應用日益廣泛；鋼鐵則具有高強度高韌性之特性；由於微弧氧化技術能夠有效提升輕金屬材料之常溫耐蝕性，故本研究利用微弧氧化技術以改變占空比與脈衝頻率之方式在純鋁及熱浸鍍鋁表面製備富含氧化鋁的陶瓷膜；本實驗分成兩個階段，第一階段以純鋁作為基材直接進行微弧氧化，藉由改變製程參數鍍製氧化鋁膜。第二階段使用低碳鋼作為底材，先進行熱浸鍍鋁作業使表面覆蓋鋁化層，接著再進行微弧氧化實驗以製備出氧化鋁膜層。本研究在微弧氧化過程中同時進行電源之電壓-電流監控與電漿光譜分析，並且分析氧化鋁膜的微結構、機械性質與抗蝕性質，以探討不同占空比對氧化鋁膜特性之影響。經實驗結果發現，隨著占空比下降，尖峰功率密度上升，氧化鋁層表面粗糙度、氧化鋁膜層厚度也隨之上升。另一方面，藉由固定占空比改變脈衝頻率時，尖峰功率密度隨著脈衝頻率增加而上升，氧化鋁膜層厚度也隨之增加。在低碳鋼熱浸鍍鋁後的表面微弧氧化的實驗部分，試片表面發出電漿弧光之主要元素為鋁和鈉，且鈉之訊號強度隨著反應時間不斷增強。經由實驗結果發現，有微弧氧化處理後的試片之表面粗糙度會些微上升，而硬度則有顯著增大，最高達到15 GPa以上，而常溫抗腐蝕性質也有明顯的改善。

Recently, the micro-arc oxidation (MAO) or the so-called plasma electrolytic oxidation (PEO) process has been widely studied and applied in industries due to its ability to create functional oxide layers on light metals. In this work, a high power current pulse power supply was used for the micro-arc oxidation coating on surfaces of pure aluminum and the hot-dipped aluminized steel substrates. The first stage of the experiment was controlling the duty cycle and frequency of power supply to fabricate five different MAO coatings on the pure Al. The second stage was a hybrid method consisting of the hot-dipped aluminizing (HDA) and MAO processes to deposit a composite ceramic coating on the surface of carbon steel plate. The HDA of carbon steel plate was executed at 710oC for 1 min. The duty cycle and frequency of MAO processes were adjusted to fabricate three different HDA plus MAO coatings. The phase analysis and microstructure of coatings were determined by X-ray diffractometer (XRD) and scanning electron microscopy (SEM), respectively. The hardness and adhesion of coatings were determined by the nanoindenter and scratch tester. The corrosion resistance of coatings was evaluated by the potentiodynamic polarization test in 0.5M H2SO4 aqueous solution. It was found that the peak power density increased with decreasing duty cycle at fixed frequency. Meanwhile, the thickness and roughness of MAO coating also increased. On the other hand, the peak power density and thickness of MAO coating increased with increasing frequency at fixed duty cycle. The main elements of the plasma were Al and Na species during the MAO process on the HDA steel surface. The intensity of Na plasma increased with reaction time. For the MAO coating on the HDA steel surface, the surface roughness slightly increased and the hardness greatly enhanced to higher than 15 GPa. In addition, the corrosion resistance of the MAO coating also improved effectively.

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