Formation of Pattern During Anodization of Tungsten

碩士 === 國立臺灣大學 === 物理研究所 === 95 === In recent years, the growth of porous oxide structures has been largely observed on metals by using anodization. Particularly, in the case of anodic aluminum oxide discovered by Masuda and Fukuda, highly ordered self-organized porous structure can be formed under o...

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Main Authors: Wei-Hsun Chen, 陳蔚勳
Other Authors: 王玉麟
Format: Others
Language:en_US
Published: 2007
Online Access:http://ndltd.ncl.edu.tw/handle/41018129251178632162
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spelling ndltd-TW-095NTU051980602015-12-07T04:04:13Z http://ndltd.ncl.edu.tw/handle/41018129251178632162 Formation of Pattern During Anodization of Tungsten 陽極處理鎢所產生的幾何圖形 Wei-Hsun Chen 陳蔚勳 碩士 國立臺灣大學 物理研究所 95 In recent years, the growth of porous oxide structures has been largely observed on metals by using anodization. Particularly, in the case of anodic aluminum oxide discovered by Masuda and Fukuda, highly ordered self-organized porous structure can be formed under optimized anodizing conditions. On the other hand, Yuzhakov et al. found that the electropolishing of aluminum results in various patterns by applying different anodic voltage and proposed a model to explain its instability mechanisms. In our experiment, we observed the formation of pattern driven by applied voltage as well on tungsten and W-oxides surface. The tungsten films were anodized in NaOH electrolytes under various conditions. Due to the high dissolution rate of W-oxides in strong basic solutions, we need to locally suppress the concentration of electrolytes above the anode to block the chemical oxidation and dissolution reactions so that the morphology of W-oxides could be retained. Amazingly, under specific conditions, it was the first time that the highly ordered nanohole array was observed on W-oxides, with period about 50nm. In the end of this thesis, we will modify the model proposed by Yuzhakov et al. to elucidate the possible instability mechanisms in our system. 王玉麟 2007 學位論文 ; thesis 48 en_US
collection NDLTD
language en_US
format Others
sources NDLTD
description 碩士 === 國立臺灣大學 === 物理研究所 === 95 === In recent years, the growth of porous oxide structures has been largely observed on metals by using anodization. Particularly, in the case of anodic aluminum oxide discovered by Masuda and Fukuda, highly ordered self-organized porous structure can be formed under optimized anodizing conditions. On the other hand, Yuzhakov et al. found that the electropolishing of aluminum results in various patterns by applying different anodic voltage and proposed a model to explain its instability mechanisms. In our experiment, we observed the formation of pattern driven by applied voltage as well on tungsten and W-oxides surface. The tungsten films were anodized in NaOH electrolytes under various conditions. Due to the high dissolution rate of W-oxides in strong basic solutions, we need to locally suppress the concentration of electrolytes above the anode to block the chemical oxidation and dissolution reactions so that the morphology of W-oxides could be retained. Amazingly, under specific conditions, it was the first time that the highly ordered nanohole array was observed on W-oxides, with period about 50nm. In the end of this thesis, we will modify the model proposed by Yuzhakov et al. to elucidate the possible instability mechanisms in our system.
author2 王玉麟
author_facet 王玉麟
Wei-Hsun Chen
陳蔚勳
author Wei-Hsun Chen
陳蔚勳
spellingShingle Wei-Hsun Chen
陳蔚勳
Formation of Pattern During Anodization of Tungsten
author_sort Wei-Hsun Chen
title Formation of Pattern During Anodization of Tungsten
title_short Formation of Pattern During Anodization of Tungsten
title_full Formation of Pattern During Anodization of Tungsten
title_fullStr Formation of Pattern During Anodization of Tungsten
title_full_unstemmed Formation of Pattern During Anodization of Tungsten
title_sort formation of pattern during anodization of tungsten
publishDate 2007
url http://ndltd.ncl.edu.tw/handle/41018129251178632162
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