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標題: | 應用原子層沉積技術改善可生物降解鎂鈣合金抗蝕性之研究 Improvement of corrosion resistance of biodegradable Mg-Ca alloy by atomic layer deposition technique |
作者: | 林丕晟 Pi-Chen Lin |
指導教授: | 林新智 Hsin-Chih Lin |
關鍵字: | 原子層沉積,原子層退火,腐蝕保護,鎂鈣合金,生物可降解植體, atomic layer deposition (ALD),atomic layer annealing (ALA),corrosion protection,magnesium-calcium alloy,biodegradable implants, |
出版年 : | 2022 |
學位: | 博士 |
摘要: | 過於快速的生物降解率是阻礙鎂合金在生物醫學領域應用的一個重要議題。透過原子層沉積(ALD)的獨有特性,原子層沉積被認為是一種適合用於提升鎂合金性能的方式。一般而言,製備上較厚或多層結構的ALD膜能達到較高耐腐蝕阻抗,而本研究採用一種逐層電漿處理的原子層電漿處理技術來提升透過熱驅動原子層沉積模式生長的二氧化鋯膜的腐蝕保護特性。原子層退火對材料特性的影響具有時間依賴性,30秒的原子層退火時間能提供二氧化鋯膜薄膜最大限度的極化阻抗提升,由原先的1.8kΩ·cm2提升至到74.7kΩ·cm2,這來自於高程度的結晶性提升,以及氧空缺數量達40個百分比的改善。與增加厚度效應相比較,30秒的原子層退火於二氧化鋯薄膜的腐蝕阻抗提升效果相當於厚度由200個循環增加到300個循環的效果,甚至原子層退火能使熱驅動原子層沉積所製備出的二氧化鋯薄膜,較電漿增益型原子層沉積製備的薄膜具有更高的腐蝕阻抗。透過等效電路研究和腐蝕行為研究,原子層退火顯著改善薄膜結晶度和缺陷,從而抑制離子擴散的機制。 本研究中也透過XRD與TEM的分析確認二氧化鉿鋯能成功的被製備於擠製態的鎂鈣合金表面。而且,二氧化鉿鋯薄膜可以提高擠製態鎂鈣合金的腐蝕阻抗,從而降低鎂鈣合金的生物降解率。腐蝕電流密度、pH值評估和腐蝕表面影像提供腐蝕速率提高的證據。與二氧化鋯薄膜相比,二氧化鉿鋯薄膜表現出更好的短期耐腐蝕性能。並且納入WST-1測定和LDH試驗,以表明二氧化鉿鋯薄膜毒性低,適用於生物植入物的保護塗層。 Excessive biodegradation rate is a critical problem for magnesium alloys in the biomedical field. With its unique properties, atomic layer deposition (ALD) is seen as a potential method that can be applied in corrosion protection for magnesium alloys. So far, using thicker film or multilayer structure design can enhance the corrosion resistance of ALD films. However, extended techniques of ALD have not been applied to such areas. In the first part of this work, atomic layer plasma annealing (ALA) that ALD films are exposed by in-situ plasma treatment can effectively enhance the corrosion protection of ZrO2 film deposited by thermal ALD mode (TALD-ZrO2). As the ALA effect is time-dependent, the influence of ALA time is investigated. The maximum enhancement of polarization resistance of ZrO2 films from 1.8kΩ·cm2 to 74.7kΩ·cm2 is found when the ALA time is 30s, which is because of the high-level crystallization and dramatic improvement of oxygen vacancy of 40%. In addition, the maximum ALA effect is relevant to the thickness effect that increases the film thickness from 200 cycles to 300 cycles. In the first part of this work, the ALA effect on the characteristics and corrosion properties of ZrO2 films are studied. Furthermore, by discussing the equivalent circuit and corrosion behavior of the system with the characteristics, the improvement of the crystallinity and defects of the films leads to the suppression of mass transfer which is the main mechanism of the ALA effect. In the second part of this study, HfZrO2 (HZO) films are deposited on an as-extruded Mg-Ca alloy. The identification of the compound is processed by XRD and TEM analysis. When the as-extruded Mg-Ca alloy is covered by the HZO films, the corrosion resistance of the alloy is enhanced. This result reflects in the decrease in corrosion rate. By involving HfO layer to ZrO2, continuous electrochemical impedance spectroscopy (EIS) is used to measure the decline of corrosion resistance. The corrosion resistance of HZO films decreases faster than that of ZrO2 films within the certain period. As the corrosion properties of HZO films are investigated, its biocompatibility is confirmed by 3-day WST-1 assay and LDH test. HZO films have low toxicity signifying that HZO films are suitable as a protective layer for biomedical implants. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/86404 |
DOI: | 10.6342/NTU202202611 |
全文授權: | 同意授權(全球公開) |
電子全文公開日期: | 2027-08-21 |
顯示於系所單位: | 材料科學與工程學系 |
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檔案 | 大小 | 格式 | |
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ntu-110-2.pdf 此日期後於網路公開 2027-08-21 | 10.74 MB | Adobe PDF |
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