金屬表面奈米塗層與疏水改質之抗腐蝕研究

A Study on Corrosion Resistance of Nano-coating and Hydrophobic Modification on Metal Surface

阮玟馨(Juan Wen-Hsin)

指導教授 ： 呂家榮

國立臺灣師範大學/理學院/化學系/碩士(2023年)

https://doi.org/10.6345/NTNU202300017

摘要

本研究旨在將電鍍鋅鋼板進行鈍化處理，先在基材表面形成性質穩定且結構緻密的氧化層，再塗佈以溶膠－凝膠法所製備之具有矽-氧-鈦網狀結構的奈米粒子封孔劑於表面，其耐鹽霧時間比未鈍化的塗層更長，在電化學測量結果也顯示更好的抗腐蝕能力。另外，藉由探討鈍化液濃度、鈍化時間以及水洗水酸鹼值對抗蝕性之影響，可以得到最佳化的製程條件，進而達到最大的腐蝕保護效果。
由於上述提到的封孔劑具有羥基，使水滴容易沾附於鋼板上，且在後續加工上也有所限制，本研究利用不含氟的十八烷基三氯矽烷對表面進行疏水改質，並與鋯鈍化皮膜結合，在表面形成疏水薄膜，接觸角可超過110°。此外，透過將樣品置於一般環境及腐蝕性溶液中，觀察接觸角隨著時間的改變，以測試薄膜在不同環境中的耐候性。
本論文利用鹽霧試驗及鹽水浸泡測試模擬高溫高濕的環境，比較不同塗層的抗蝕性能。亦透過電化學交流阻抗及塔弗極化曲線進行分析，在更短的時間內評估皮膜之抗腐蝕能力。並且，在掃描式電子顯微鏡下可以看到樣品的真實形貌，再搭配能量色散X射線譜，得到各個元素的分布及含量比例，藉此確認材料確實有成膜於鋼板表面。

關鍵字

金屬表面處理 ； 鋯鈍化 ； 奈米塗層 ； 疏水改質 ； 自組裝薄膜

並列摘要

The purpose of this study is to passivate the electro-galvanized steel sheet in order to form a stable and dense oxide layer on the surface of the substrate, and then a nanoparticle sealing agent with silicon-oxygen-titanium network structure prepared by sol-gel method is coated on the surface. Then, it becomes an eco-friendly zirconium passivation anti-corrosion coating, which has a longer salt spray resistance time than the untreated coating, and also shows better results in the electrochemical impedance measurement. In addition, by considering the effects of passivation solution concentration, passivation time and pH value of washing water on corrosion resistance, we can optimize the process conditions to achieve the maximum corrosion protection.
Since the sealing agent mentioned above has hydroxyl groups, which make water droplets easily adhere to the steel plate, and it is also limited in subsequent processing. Therefore, in this study, fluorine-free N-octadecyl trichlorosilane was used to modify the surface into hydrophobic and combine it with zirconium passivation film to form a hydrophobic film on the surface with a contact angle of over 110°. In addition, by placing the samples in a general surrounding and a corrosive solution, the change of the contact angle with time was observed to test the weatherability of the film in different environments.
In this thesis, the salt spray test and salt water immersion test are used to simulate the environment of high temperature and high humidity to compare the corrosion resistance of different coatings. Electrochemical impedance spectroscopy and tafel polarization curve are also analyzed to evaluate the corrosion resistance of the film in a shorter time. Furthermore, the real appearance of the sample can be seen under the scanning electron microscope, and then the distribution and content ratio of each element can be obtained with energy dispersive X-ray spectroscopy, thereby confirming that the material has indeed formed a film on the surface of the steel plate.

並列關鍵字

surface treatment of metal ； zirconium passivation ； nano-coating ； hydrophobic modification ； self-assembled film

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