本實驗利用微弧氧化在6061鋁合金上鍍製氧化鋯MDO氧化膜，並針對其顯微結構、硬度、XRD、韌性進行分析。
首先在鹼性電解液中添加含鋯鹽類(K2ZrF6)並在不同負電壓下進行實驗。由實驗結果發現，在6061鋁合金上鍍製氧化鋁MDO氧化膜比鍍製氧化鋯MDO氧化膜容易許多，由於含鋯鹽類在鹼性容易中形成Zr(OH)4顆粒沉澱，相較於鍍製氧化鋁MDO氧化膜，Zr(OH)4顆粒使得在微弧氧化過程中導致膜層孔洞多且厚度不均。若是將含鋯鹽類溶於酸性溶液中則可避免形成Zr(OH)4顆粒沉澱，但是酸性電解液會對試片及陰極造成破壞，無法鍍製緻密平整的氧化鋯MDO氧化膜。於是在鹼性電解液中添加分散劑(NaPO3)6 解決的Zr(OH)4顆粒沉澱問題，經過一系列不同負電壓實驗結果可知負電壓100 V時有最佳結果，XRD結果為t相氧化鋯(t-ZrO2)，但還是有小孔洞散佈在氧化鋯鍍層內部，於是在含鋯鹽類電解液中添加了鋁酸鈉(NaAlO2) 2 g/L，負電壓100 V時有最佳結果，膜層緻密性上升，XRD結果依然為t相氧化鋯(t-ZrO2)。當含鋯鹽類電解液中鋁酸鈉大於 4 g/L，膜層厚度及緻密性卻是下降，是因為鋁酸鈉是弱鹼性，添加過多導致Zr(OH)4顆粒沉澱問題，XRD會以-Al2O3為主，以上結果皆為電壓控制的電源模式進行微弧氧化，當膜層生長厚度上升，則電流開始下降，沒有足夠能量使膜層繼續成長且緻密化。
為了追求更好膜層緻密性及厚度，改成電流控制的電源模式進行鍍製氧化鋯的微弧氧化實驗，沒有添加鋁酸鈉含鋯鹽類電解液結果是整體厚度雖然有幅上升，但孔洞更大了，添加鋁酸鈉含鋯鹽類電解液電流在0.3~0.5 A時有較佳的結果，之後增加氟鋯酸鉀含量來增加氧化膜緻密性，並控制微弧氧化製程後期之電壓，減少大尺寸arc對氧化膜之破壞，XRD會以t-ZrO2為主，但m-ZrO2增加，相較於MDO氧化鋁膜，氧化鋯膜具有較佳韌性，但過多氟鋯酸鉀含量導致韌性下降，抗腐蝕測試結果顯示出氟鋯酸鉀含量上升，膜層厚度及緻密性上升，所以抗腐蝕性也上升，氟鋯酸鉀到達22g/L時，由於表面大孔洞以及基材與膜層之間的裂痕貫穿整個膜層，導致MDO氧化膜失去保護效果，於是抗腐蝕性下降。

Zirconia composite coating was prepared on 6061 aluminum alloy by microarc discharge oxidation. Tthe microstructure, hardness, XRD and toughness have been investigated in this study.
First, the the experiments were carried out in alkaline electrolyte containing K2ZrF6 at different negative voltage. The results indicated that it is easier to form alumina than Zirconia for MDO coating on aluminum alloy, because Zr(OH)4 partilce were formed in alkaline easily. Compare with formation of alumina MDO coating, Zr(OH)4 partilce made a lot of pores during coating and which not uniform coating. K2ZrF6 dissolves in acidity electrolyte to prevent formation of Zr(OH)4 partilce. But the acidity electrolyte will corroded the cathode lead zirconia composite coating not to be compact. The problem of Zr(OH)4 partilce precipitation was solve by adding dispersant (NaPO3)6. There is a good experimental result that was carried out at negative voltage 100 V what XRD result indicated t-ZrO2 mainly. In order to get more compact coating, the sodium aluminate (NaAlO2) 2 g/L was added into the K2ZrF6 electrolyte. There is also a good experimental result was carried out at negative voltage 100 V and the coating was more compact than before and XRD result indicated t-ZrO2 mainly. When the contain of aluminum sodium aluminate in the K2ZrF6 electrolyte is greater than 4 g / L, the thickness and density were decreasing . Because sodium aluminate is weak alkaline, it caused the problem of Zr(OH)4 partilce precipitation when sodium aluminate is too much. XRD result indicated -Al2O3 mainly. Above MDO result were carried by voltage control. When the coating thickness is increasing ,the current is decreasing , and than there is no energy to let coating to grow and to be more compact .
In order to get more compact and more thicker coating, experiment process was change from voltage control to current control. The result show that the thickness were increase without sodium aluminate, but there were still some big pores in the coating. Better result were carried out with sodium aluminate by 0.3~0.5A in K2ZrF6 electrolyte.. And then the density were more compact by increasing contain of K2ZrF6. The voltage was limited at prosess of later stage to avoid damage from larger size of arc. XRD result indicated t-ZrO2 mainly, and the more m-ZrO2 were forming, when the contain of K2ZrF6 increasing in electrolyte. Zirconia MDO coating have higher toughness than alumina MDO coating, but it cause toughness decrease when K2ZrF6 contain too much in electrolyte . Corrosion resistance test results show that when the contain of K2ZrF6 increasing in electrolyte, the thickness and density of the coating increase , and the corrosion resistance increased. The corrosion resistance decreases due to the large pores between the surface layer and the substrate ,and the cracks were throughout the coating, when K2ZrF6 reached 22g / L.

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