氧化鈦薄膜之電化學特性與結構分析研究

The Electrochemical Characteristics and Microstructure Analysis of Titanium Oxide

本研究主要探討α-Ti經酸洗後分別於350℃至750℃間進行氧化處理所得之氧化鈦組織的電化學特性。實驗中採用純鈦及氧化鈦旋轉圓柱電極，於1M H2SO4溶液中進行陽極極化測試與交流阻抗測試，並利用SEM/EDS及XRD觀察分析純鈦與氧化鈦相組成及其界面顯微組織作為輔證。研究結果得知，α-Ti在各種不同溫度氧化所得之氧化鈦，陽極鈍態電流會隨著氧化溫度提高而降低；此亦可由交流阻抗偏置鈍態電位測試中，傳導阻抗值（Rt）值印證。氧化溫度愈高則表面裂紋愈寬，但表面裂紋寬度增加並未提高鈍態解離速率。此外，結合XRD分析同時提供不同裂解溫度之氧化鈦結構則由較不穩定之銳鈦礦轉變成穩定之金紅石，氧化層顏色亦隨價數不同產生多樣的顏色變化。

The aim of this research is to investigate the electrochemical behavior of TiO2 which was obtained from different pickling methods of £\-Ti and then oxidized at 350 as well as 750¢J. The RCE electrode was made from pure titanium and titanium oxide was used in all experiments. Anodic polarization and AC impedance test of the RCE were carried out in 1 M H2SO4 solution; furthermore, SEM, EDS, and XRD were used to observe and analyze the interfacial microstructure of pure titanium and titanium oxide. From the results, the anodic passive current decreased with increasing the oxidation temperature of £\-Ti. The similar results were also achieved with AC impedance test polarized in the passive potential, the higher oxidation temperature and the lower the charge-transfer resistance (Rct). The width of the surface crack enlarged as the oxidation temperature was raised, but the passive dissolution rate increased with increasing the surfacecrack width. The XRD results show that TiO2 structure could be unstable anatase or stable rutile at different oxidation temperatures. Besides, the oxides may have different color when TiO2 was constructed in different valence bond.