摘要: | 腐蝕是導致金屬材料劣化的關鍵問題,它的影響層面包含基礎設施、環境保護和電子產品 等多領域的可靠性和安全性。過去的研究已經有許多防腐策略被提出,而其中以無機奈米 材料為填料的奈米高分子複合材料被認為是一極具潛力的方法。近期,以石墨烯和二維材 料為填充劑的奈米複合材料被認為是克服這一問題的理想策略,主要是石墨烯對水氧分子 的阻隔性。然而,石墨烯本質上是導電的,當將其直接塗覆在金屬上或在聚合物複合塗層 中超過一定的負載閾值的填料時,它會促進電偶腐蝕發生,從而導致更嚴重的腐蝕。 近期研究可以通過填料的選擇來解決此問題,選擇填料具有高的電絕緣特性、奈米片結構 以及與高分子聚合物基體的高分散性/相容性,並具有高的熱/時效穩定性,藉以形成抵抗 氣體或液體滲透的超長擴散路徑。因此在本工作中,我們選擇使用氟化的電化學剝離石墨 烯(Fluorinated electrochemically exfoliated graphene, F-ECG)得到氟化石墨烯(FG)來解決了這 些問題。 研究結果顯示,作為填料的氟化石墨烯(FG)在環氧樹脂中的負載量僅為 1 wt.%,可以 達到極低的腐蝕率(最低腐蝕率(corrosion rate, CR)=7.83×10-8 mm/year;最低電流密度= 3.37×10-12 A cm-2; 平均腐蝕率 = 9.4×10-7 mm/year; 平均電流密度 = 4.1×10-2 nA cm-2 。 CR 可通 過增加填料(FG)的含量而逐步遞減,這證明了填料的有效分散和優異的的擴散阻障, 因此增加了腐蝕性介質從陰極滲透到陽極的超長擴散路徑。由於電偶腐蝕的減少和活性腐 蝕物質(ACS)的極低擴散係數,獨特的 FG 優於過去文獻中以石墨烯及 BN 等相似的二 維材料作為複合材料的填充物。同時,為了實際應用,我們展示了軟性印刷電路板(PCB) iii
藉由 FG-環氧複合塗層,具有優異的抗蝕性能,此外,由於 FG 兼具高電絕緣性、疏水性 和崩潰電壓,因此進一步防止了短路的風險,能使其在惡劣環境下,電子設備能具有高的 可靠度。這項工作提供一種新的防腐蝕技術,並為探索高阻水阻氣的複合材料提供了一種 新的研究策略。;Corrosion, an issue that leads to the fracture of metal materials, which affect the reliability and safety of versatile fields such as infrastructure, environmental protection, and electronics. Many strategies of anti-corrosion have been proposed, while the polymer nanocomposite with inorganic materials as filler was been regarded as a more feasible route. Currently, the polymer nanocomposite with graphene and 2D materials as fillers are considered an ideal strategy to overcome this issue since graphene is highly impermeable to molecules; however, graphene is essentially electrically conductive, when it was coated directly on metal or been used above a certain loading threshold as filler in a polymer composite coating, it promotes the galvanic corrosion leading to more acute corrosion. This problem can be solved by choosing a filler that reveals electrical insulating property together with a nano-sheet structure and high dispersibility/compatibility with the polymer matrix as well as the high thermal/long-term stability to create an elongated diffusion path against the gas or liquid permeation. Here, the fluorinated graphene (FG), obtained by fluorination of the electrochemically exfoliated graphene (F-ECG) solves these issues. As, we have shown that the fluorinated-graphene (FG) flakes as filler with only 1 wt.% loading in the epoxy matrix, allows achieving a leading value among the reported literature on corrosion performance average corrosion rate (CR) = 9.4×10-7 mm/year; current = 4.110-2 nA cm-2 (lowest corrosion rate (CR) = 7.8310-8 mm/year; current = 3.37 10-12 A cm-2). The CR decreases monotonically by increasing the filler (FG) loading, demonstrating the effective dispersion of filler and outstanding diffusion barrier that increases the ultra-long diffusion path for corrosive media penetration from cathode to anode. The FG was found to be a unique and ideal filler outperforming v
other reported graphene- and BN- related 2D materials owing to the diminishment of galvanic corrosion and the extremely lower diffusion coefficient of active corrosion species (ACS). Meanwhile, for practical application, the FG-epoxy composite coating on flexible printed circuit board (PCB) was proved for achieving superior corrosion inhibition while preventing the risk of electrical short circuit due to the high electrical insulating, hydrophobic nature, and breakdown voltage of FG, making it durable passivation on electronic devices under harsh environment. This work shows a break-through in anti-corrosion technology and provides a novel strategy in exploring extremely impermeable composites. |