微弧氧化生長銳鈦礦氧化鈦薄膜於鈦金屬板之研究及其光觸媒效能之研究

Study on the Micro-Arc Oxidation Grown Anatase TiO2 Films on Titanium Plate and Their Photocatalyst Effciency

薛涵覺(Han-Jiue Shine)

指導教授 ： 唐自標

國立臺北科技大學/工程學院/材料及資源工程系研究所/碩士(2010年)

https://doi.org/10.6841/NTUT.2010.00178

摘要

微弧氧化技術在這十幾年來發展相當迅速，由於其工序操作簡單方便、耗水量少、廢液少，而溶液中不含Cr6+、Pb2+等有害物質，符合現時綠色製造的發展要求。微弧氧化透過參數控制可得銳鈦礦結構，且經微弧氧化處理過後的試片表面呈現多孔狀的外貌，可有效增加二氧化鈦薄膜的比表面積。有利於紫外光的吸收。製程中會產生高能電弧，可快速在金屬表面生成氧化膜，除了節省製程時間外，還可增加氧化膜的結晶性，且可生成多孔的銳鈦礦相二氧化鈦薄膜。
本研究將利用微弧處理於鈦金屬薄板上製備二氧化鈦薄膜，改變電流密度、放電電壓、頻率以及定電流下控制時間等參數，並嘗試摻雜不同濃度的Fe3+，接著再將製成之光觸媒薄膜進行亞甲基藍的光降解實驗。
研究結果顯示：提高電壓值能夠使陰離子深入內部，對於相及膜厚的變化相當明顯，因此主要的差異會反映在相及膜厚上。當電壓值達300 V時可得到47％的降解率。提高電流值只會讓陰離子累積在表層，不易深入內層，因此對膜厚效果增加相當有限，所以主要的差異會反映在地形外貌上。當電流值達0.25 A時可得到59％的降解率。為了薄膜的表面保持均一的模樣，施加脈衝是必須的；而且頻率數越高薄膜表面就越平均，但是超過了550 Hz後膜厚會下降。當施加頻率為550 Hz時可得到65％的降解率。微弧氧化時間越久地形外貌起伏會越崎嶇，但是30分後地形起伏會開始傾向平整。當微弧時間為50分時可得到56％的降解率。藉由在電解液中摻雜雜質改善氧化層的光觸媒是可行的，當Fe3+摻雜量達0.1 g/L可得到68％的降解率。但是本研究所選用的電解液為草酸，極易跟FeCl3起反應，因此達0.4 g/L後反而會造成降解率的下降。
總而言之，選用草酸作為電解液並不適用於微弧氧化的實用化這方面用途，但是用來做為研究微弧氧化各參數之影響的題材倒是可行的。另外可以證實藉由在電解液中摻雜雜質，改變生成之二氧化鈦薄膜的性質是可行的。

關鍵字

微弧氧化 ； 二氧化鈦薄膜 ； 銳鈦礦 ； 過度元素 ； 光觸媒

並列摘要

Micro-arc oxidation technology in the last ten years to develop quite rapidly, because of its process is easy and simple, water less, waste less, while the electrolyte does not contain Cr6 +, Pb2 + and so on hazardous substances to conform to environmental protection requirements. The results indicate that micrometer-scale porous anatase TiO2 film can be fabricated by Micro-arc oxidation, and by micro-arc oxidation treatment after the surface of the specimens showed porous appearance, which can effectively increase the surface area of TiO2 films. The process will produce high-energy arc can be generated quickly in the surface of metal oxide film, in addition to to save process time, but also increase the crystalline oxide film, and can generate porous anatase TiO2 film.
In this study, interest in using micro-arc oxidation of titanium plate were prepared on TiO2 thin films, to change the electric current, discharge voltage and frequency, and try different doping concentration of Fe3 +, and then test Photocatalys activity of TiO2 thin films by methylene blue decomposition.
The results showed: Enhance the voltage to make the internal anion in-depth, and thickness for the phase changes are obvious, so the main difference will be reflected on the phase and thickness. When the voltage value of 300 V when the degradation rate of 47% available. Enhance the current value would only anions accumulate in the surface, the inner depth is not easy, so the effect of increasing the film thickness is limited, so the main difference will be reflected in the topography. When the current value of 0.25 A obtained when 59% of the degradation rate. In order to maintain the flat surface of film, it is necessary to impose pulse. And the higher the frequency the more flat film surface, but after more than 550 Hz will reduce the film thickness. When the applied frequency is 550 Hz when the degradation rate of 65% available. The longer micro arc oxidation film surface will become rough, but more than 30 minutes will begin to tend to flat the surface. When the micro arc oxidation time of 50 minutes the degradation rate of 56% available. Doped by impurities in the electrolyte layer to improve the photocatalytic oxidation is feasible, When Fe3+ doping capacity of 0.1 g/L the degradation rate of 68% available. However, the electrolyte used in this study as oxalic acid, easily react with FeCl3, so up to 0.4 g/L on the contrary will result in the degradation rate of decline.
In short, use oxalic acid as the electrolyte does not apply to micro-arc oxidation of practical use in this regard, but is used to study oxidation as the effect of various parameters of subjects might be feasible. Also can confirm that the doping by impurities in the electrolyte change generate the nature of titanium dioxide thin films is feasible.

並列關鍵字

Micro-arc oxidation ； TiO2 film ； anatase ； transition element ； Photocatalyst

參考文獻

[1] A. L. Yerokhin, X. Nie, A. Leyland, and A. Matthews, "Characterisation of Oxide Films Produced by Plasma Electrolytic Oxidation of A Ti-6Al-4V Alloy", Surface and Coatings Technology, 130 (2000) 195-206.

[2] Y. Wang, T. Lei, L. Guo, and B. Jiang, "Fretting wear behaviour of microarc oxidation coatings formed on titanium alloy against steel in unlubrication and oil lubrication", Applied Surface Science, 252 (2006) 8113-8120.

[3] L. H. Li, Y. M. Kong, H. W. Kim, Y. W. Kim, H. E. Kim, S. J. Heo, and J.Y.Koak, "Improved Biological Performance of Ti Implants Due to Surface Modification by Micro-Arc Oxidation", Biomaterials, 25 (2004)2867-2875.

[6] F. Liu, F. Wang, T. Shimizu, K. Igarashi, and L. Zhao, "Hydroxyapatite Formation on Oxide Films Containing Ca and P by Hydrothermal Treatment", Ceramics International, 32 (2006) 527-531.

[7] G. X. Tang, R. J. Zhang, Y. N. Yan, and Z. X. Zhu, " Preparation of Porous Anatase Titania Film", Materials Letters, 58 (2004) 1857-1860.