本論文主要探討AZ91D鎂合金進行電漿電解氧化 (Plasma Electrolytic Oxidation, PEO) 鍍膜中，週期中工作及休息時間的重要性以及動態混合鍍膜所帶來的效益。回顧以往弱工作現象的論文，大多沒有針對參數做進一步的研究，故無法找出真正影響弱工作現象的關鍵點，若能摸清發生弱工作現象 (Soft regime)所需要的參數條件及參數所代表的物理意義，必能預期某參數下所得到的相的特性。以往的研究，在參數的調整中，若要發生弱工作現象，有的控制電流比，有的探討電荷比，所得結果亦莫衷一是；因此本研究主張電流比 (IR)及電荷比 (CR)都必須一起納入考量。實驗結果顯示，電流比在大於1時 (IR=1.1)無論電荷比 (CR)的大小，實驗時間一小時內皆不會發生弱工作現象；電流比在小於1時 (IR=0.9)，最快6分鐘時即會進入弱工作現象。電荷比 (CR)是正反向電流比及週期積分面積的比值，在固定電流大小下，藉由正反向工作週期值的調整能微調弱工作現象準確的發生時間，在電流比大於1時 (IR=1.1)，電荷比呈現出越小越早發生弱工作現象；在電流比小於1時 (IR=0.9)，電荷比則呈現出越大越早發生弱工作現象。
為定量討論電流比及電荷比的影響。本研究的參數中，所有點座標皆是固定正電流 (I+)為1.3並調整負電流 (I-)而獲得不同的IR值 (0.7、0.9、1.1、1.3)，除此之外週期中的陽極工作時間 (ton+)及陽極休息時間 (toff+)皆固定在520及640 µs，藉此所有實驗結果之變數原因都將指向為負週期所帶來的影響，藉由調整ton-獲得不同的CR值 (1.25、1.36、1.47)，於此IR及CR共12個座標組成作為後續動態混合鍍膜的圭臬。本實驗結果顯示，在IR=1.3, CR=1.47下膜層外層為多孔結構並有著超過55%的MgAl2O4相含量，此參數能獲得最大的向外生長膜層平均厚度 (79.34 µm)，在機械性質上有著最好的前景，腐蝕阻抗測試中的RP值為5.379*107 Ω/cm2；在IR=0.9, CR=1.25時向外生長膜層平均厚度僅有31.49 µm，但由於進入弱工作區域而有向內生長的緻密膜層，向內生長膜層平均厚度為178.33 µm，在腐蝕阻抗測試中的RP值提升到9.950*109 Ω/cm2。藉由電流比、電荷比及週期的控制，在鎂合金膜層性質上已達到一個新的水平。
在進一步的動態混合鍍膜中，分別採用不同參數以前後10+20分鐘接續的方式進行實驗。實驗結果顯示，在使用動態混合鍍膜製程後 (IR=1.3, CR=1.47) + (IR=0.9, CR=1.25)，相較單一參數的製程 (IR=1.3, CR=1.47)，腐蝕阻抗從5.379*107 Ω/cm2提升到3.838*109 Ω/cm2，且向外生長膜層平均厚度相較單一參數的製程 (IR=0.9, CR=1.25)從31.49 µm提升到42.76 µm；而前後順序顛倒的動態混合鍍膜製程中 (IR=0.9, CR=1.25) + (IR=1.3, CR=1.47)，雖說相較前述動態混合鍍膜腐蝕阻抗下降了2個次方 (4.812*107)與單一參數的製程 (IR=1.35, CR=1.47)相當，但向外生長膜層平均厚度上也從79.34 µm稍微提升到81.78 µm。也就是說使用動態混合鍍膜法，能將既有的膜層性質再作進一步的改良。
以後製程的時間為參數的實驗中，以IR=0.9, CR=1.25, 10 min or IR=0.9, CR=1.47, 10 min為前製程，IR=1.35, CR=1.47為後製程，此兩組腐蝕阻抗皆隨後製程時間的增加而越來越低；但若以IR=1.3, CR=1.47, 10 min為前製程，IR=0.9, CR=1.25, or IR=0.9, CR=1.47為後製程，此兩組皆是隨著後製程時間的增加，腐蝕阻抗呈現先升後降的結果，在 (IR=1.35, CR=1.47) + (IR=0.9, CR=1.25)這組中，在鍍膜時間10+10分鐘下腐蝕阻抗最終提升到4.049*1010 Ω/cm2。即製程時間的掌控及製程上先後順序的選擇能決定膜層的優劣。同時也顯示出動態混合鍍膜製程對於PEO具有一定的發展潛力。

This thesis discusses the importance of cycle and the benefits of dynamic hybrid coating in the plasma electrolysis oxidation (PEO) of AZ91D magnesium alloy. Most of the previous papers did not do further research on the parameters, so it is impossible to find the key points that really affect the Soft regime. If we can figure out the parameter conditions and the physical significance of the parameters required for the occurrence of Soft regime, we can expect the properties of the film.
Experimental results show that when the current ratio is greater than 1 (IR=1.1), no matter how small the charge ratio (CR) is, Soft regime will not occur within one hour; when the current ratio is less than 1 (IR=0.9), the fastest 6 minutes will enter the stage of Soft regime. On the other hand, when the current ratio is greater than 1 (IR=1.1), the Soft regime occurs earlier as the charge ratio is smaller; when the current ratio is less than 1 (IR=0.9), the Soft regime occurs earlier as the charge ratio is bigger.
In the parameters of this study, the I+ of all point coordinates is fixed at 1.3 and I- is adjusted to obtain different IR values (0.7, 0.9, 1.1, 1.3). In addition, ton+ and toff+ are fixed at 520 µs and 640 µs, and the ton- is adjusted then it can obtain different CR values (1.25, 1.36, 1.47). IR and CR constitute 12 working conditions in the first and the second quadrants of the coordinates for the subsequent dynamic hybrid coating. The results of this experiment show that the film has more than 55% MgAl2O4 phase at IR=1.3, CR=1.47, and it can obtain the maximum thickness of the outgrowth film (79.34 µm), which has the best prospects in mechanical properties. The RP value in the corrosion resistance test is 5.379*107 Ω/cm2; The thickness of the outgrowth film is only 31.49 µm at IR=0.9, CR=1.25, but there is a dense ingrowth film due to entering the Soft regime. The thickness of the inward-growth film is 178.33 µm. The RP value of the coating is increased to 9.950*109 Ω/cm2 in the corrosion resistance test.
Two different sets of parameters were used in the dynamic hybrid coating, and the experiment was conducted in a sequential manner that the former is 10 minutes, the latter is 20 minutes. The experimental results show that the dynamic hybrid coating process (IR=1.3, CR=1.47, 10 min + IR=0.9, CR=1.25, 20 min) compared with a single parameter process (IR=1.3, CR=1.47, 30 min), the corrosion resistance from 5.379 *107 Ω/cm2 increased to 3.838*109 Ω/cm2, and the thickness of the outward-growth film layer was increased from 31.49 µm to 42.76 µm compared to the single parameter process (IR=0.9, CR=1.25, 30 min).
The reverse order of the dynamic hybrid coating process (IR=0.9, CR=1.25, 10 min + IR=1.3, CR=1.47, 20 min), although compared to the previous parameter (IR=1.3, CR=1.47, 10 min + IR=0.9, CR=1.25, 20 min) decreased by ten to the power of two (4.812*107 Ω/cm2) in the corrosion resistance test, which is equivalent to a single parameter process (IR=1.35, CR=1.47, 30 min), but the thickness of the outgrowth film layer also increased from 79.34 µm to 81.78 µm.
In the experiment with the post-process time as the working parameter, under the experiment with IR=1.3, CR=1.47, 10 min as the previous process, as the post-process time increases, the corrosion resistance will show the results of first rise and then fall, but if IR=0.9, CR=1.25 or 1.47, 10 min is the experiment of the previous process, the corrosion resistance is lower as the process time increases.

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