LZ91鎂鋰合金雙極脈衝微弧氧化研究

Bpolar pulsed micro-arc oxidation on a LZ91 Mg-Li alloy

陳欽聖(Chin-Sheng Chen)

指導教授 ： 楊智富 ； 楊木榮

大同大學/工程學院/材料工程學系所/碩士(2009年)

摘要

本研究藉由掃描式電子顯微鏡/能量散佈光譜儀(SEM/EDS)、X光繞射儀(XRD)、T原子力顯微鏡(AFM)、T膜厚計、粗度儀、及恆電位儀等設備，探討LZ91(Mg-9Li-1Zn)鎂鋰合金在雙極(Bipolar)微弧陽極處理脈衝波形(I-T波形)參數條件與不同濃度之電解液(包括四硼酸鈉Na2B4O7、氫氧化鈉NaOH、及矽酸鈉Na2SiO3)下所生成陽極膜的表面形態、厚度、粗糙度與耐蝕性。結果顯示，本研究所探討之電解液成份中，以10 g/L Na2SiO3、14 g/L NaOH、及6 g/L Na2B4O7所構成者，可獲最佳之微弧陽極處理結果。在Bipolar脈衝波形中，當正極電流I onP+P之時間(T on +)及短暫零電流之時間(T off +)時間越短，陽極膜層之放電孔洞較小，隨著T on + 時間及T off +時間的增加，陽極膜放電孔洞變大，耐蝕性隨放電孔洞變大而下降。此外，在所測試的Bipolar陽極處理脈衝波之Duty Ratio 與頻率實驗參數中，以10%Duty Ratio及200 Hz頻率條件下可獲得具最佳抗蝕性之陽極膜，其極化電阻(Rp)值由未處理前之7.5×105Ω提升至處理後之3.8×107Ω。

關鍵字

鎂鋰合金 ； 氧化鎂 ； 微弧氧化 ； 抗蝕性

並列摘要

This study aims to investigate pulsed bipolar of Micro-arc Oxidation (MAO) treatment on a Mg-9Li alloy under a variety of electric and electrolytic conditions. The main variables in the bipolar pulse of Micro-arc Oxidation treatment include T on+, T off +, Duty Ratio and frequency of the bipolar pulse electric wave and individual concentrations of NaB2BBB4BOB7B, NaOH, and NaB2BSiOB3B of the electrolyte. Examinations of the resulted oxidation films were carried out by using SEM, EDS, XRD, AFM, surface topology interferometer, coating thickness gauge, and potentionsate. The results showed that the electrolyte consisted of 10 g/L Na2SiO3, 14 g/L NaOH and 6 g/L Na2B4O7 yields the best outcomes of the bipolar pulse micro-arc oxidation treatment. It was found that the average size of the electric dischange holes in the oxide film decreases with decreasing T on+ and T off +, which leads to an improvement in the corrosion resistance of the protective oxide film. It was also found that the bipolar pulse waves with 10% duty ratio and 200 Hz frequency give the most satisfactory results of pulsed bipolar of micro-arc oxidation treatment of Mg-9Li alloy with an impressive Rp value of 3.8×107Ω, which is far better than that of the untreated Mg-9Li alloy(Rp=7.5×105).

並列關鍵字

Mg-Li alloy ； MgO ； Micro-arc Oxidation ； Corrosion Resistance

參考文獻

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