Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/9918
標題: Synthesis of barium titanate films on Ti-coated substrates by anodic oxidation
電化學陽極氧化法於異質基材上製備
作者: Chan, Pei-Shuan
詹佩諠
關鍵字: 陽極氧化
anodic oxidation
鈦酸鋇
BaTiO3
出版社: 材料工程學研究所
摘要: 本研究以電化學陽極氧化法於鍍鈦膜異質基材上製備鈦酸鋇膜,所使用的異質基材分別為矽及聚對苯二甲酸乙二酯(PET),而以0.5 M 醋酸鋇及2 M 氫氧化納混合溶液(pH>13)為電解液,並在溫度55℃時製備鈦酸鋇膜。 在鍍鈦膜矽基材(Ti/Si)上以定電壓及掃描電壓在低於10 V下進行陽極氧化時,溶液的置入過程使用兩種不同方式,在靠近陽極氧化溫度時(E-Nh)選用定電壓為2.5 V、3 V、5 V及7 V,改變陽極氧化的時間,由X光繞射分析得知在定電壓2.5 V、3 V及5 V分別氧化3小時、24小時及10小時可製備出立方相鈦酸鋇,但在7 V則未製備出鈦酸鋇,經場發射電子顯微鏡觀察生成之鈦酸鋇為球狀。在掃描電壓模式下選用截止電壓分別為3 V、5 V及7 V,經X光繞射分析得知在截止電壓7 V時製備出鈦酸鋇,而在截止電壓3 V則有二氧化鈦生成。另外實驗中在較高溫時(約100℃沸騰時)置入電解液(E-h),冷卻至氧化溫度時,分別於定電壓3 V及5 V及掃描截止電壓3 V、5 V及7 V進行陽極氧化,由X光繞射結果顯示在均可生成立方相之鈦酸鋇,所生成之鈦酸鋇皆為球狀。 於鍍鈦膜PET(Ti/PET)上以E-Nh定電壓3 V進行陽極氧化,時間分別為1.5、2及3小時,經X光光電子能譜儀分析得知在氧化3小時生成鈦酸鋇。而在掃描電壓模式,在E-h掃描截止電壓3 V進行陽極氧化,並未分析出其結晶相,但對照其微結構與Ti/Si上相同氧化條件相似,但目前於Ti/PET上所製備出鈦酸鋇膜有溶解現象,造成膜並非連續性。 截至目前本實驗製備鈦酸鋇膜的最佳條件,於Ti/Si上是以電解液由高溫降至氧化溫度的配置方式,定電壓5 V模式進行陽極氧化24小時,此時所製備出的鈦酸鋇膜晶粒大小均勻且緻密,大小約為60-100 nm。於Ti/PET上根據目前分析結果最佳製程參數是以定電壓3 V陽極氧化3小時,製備出晶粒大小約為60-200 nm的鈦酸鋇。 由各項結果分析中發現於Ti/Si上製備鈦酸鋇時,使用不同的兩種溶液置入電解槽方式(E-Nh及E-h),其結果有所不同可能是因鈦酸鋇生成機制中產生不相同反應導致,可能與溶解再結晶的形成機制相關,而於Ti/PET上製備出的結果與Ti/Si不同其可能影響原因很多,其中也可能與成長過程中反應機制相關。
The objective of this research is to synthesis BaTiO3 on Ti-coated substrates including Si and PET by electrochemical anodic oxidation. Anodic oxidation temperature was conducted at 55℃ using the electrolyte of 2 M sodium hydroxide and 0.5 M barium acetate mixed solution. Potentioldynamic and potentiostatic modes below 10 V were used for Ti/Si substrates. Two different electrolyte initice temperatures were employed. One approaches 55℃(E-Nh), and the other one was close to 100℃(E-h). The experiments performed by using E-Nh potentiostatic mode untilied preset voltages of 2.5 V, 3 V, 5 V and 7 V. Anodic oxidation times were varied from 1 to 24 hours. X-ray diffraction spectra showed that cubic BaTiO3 were present at 2.5 V, 3 V, and 5 V respectively for 3, 24, and 10 hours. There was no cubic BaTiO3 at 7 V. Potendynamic mode was employed using the cut-off voltages in the range of 0—7 V. X-ray diffraction results showed that the films were cubic BaTiO3 at 7 V and rutile TiO2 at 3 V. Using the E-h potentiostatic mode at 3 V and 5 V, X-ray diffraction results showed that cubic BaTiO3 existed in all cases. The BaTiO3 particles were spherical examined by field-emission scanning electron microscopy. BaTiO3 was synthesized by the E-Nh potentiostatic mode at 3 V for Ti/PET substrates. Anodic oxidation times were 1.5, 2, and 3 hours. X-ray photoelectron spectroscopy results showed that BaTiO3 existed after anodic oxidation for 3 hours. Field-emission scanning electron microscopy results revealed that the particles were spherical similar to those on Ti/Si. The growth of BaTiO3 films at constant voltage of 5 V anodic oxidation for 24 hours is the best condition hitherto on Ti/Si substrates. However Potentiostatical mode at 3 V anodic oxidation for 3 hours is the best parameter on Ti/PET substrates. At present according the analytic measurement we think that the mechanisms of formation reaction could have some different for E-Nh and E-h on Ti/Si substrates. The possible formation mechanisms were all related to dissolution and crystallization. The results were differently for Ti/Si and Ti/PET substrates. The results may be related to the reaction mechanisms.
URI: http://hdl.handle.net/11455/9918
Appears in Collections:材料科學與工程學系

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