Abstract

The corrosion protection of aluminum alloys is severely compromised by marine environments, demanding the formulation of efficient protective coatings. Epoxy resin, diglycidyl ether of bisphenol A (DGEBA), and curing agent diethylenetriamine (DETA) were used with the mixing ratio of 100:12 to synthesize functionalized SiO₂/GO-based composite coatings and investigate the corrosion protection efficacy for aluminum alloy AA6061 in marine environments. To boost the coatings' barrier and anticorrosive attributes, functionalized silica (FSiO₂, with 0, 3, 6, 9, 12, and 15 wt%) and graphene oxide (GO) were jointly incorporated into the DGEBA/DETA epoxy-hardener system for producing composite coatings. The functionalization of silica particles using 3-aminopropyl-triethoxysilane and synthesis of GO was successfully carried out, according to the Fourier transform infrared spectroscopy evidence. The structural properties were investigated by X-ray diffraction. The hydrophobicity tests were conducted for the measurement of the contact angles. The highest static contact angle (126° ± 2) and the lowest contact angle (74° ± 1.5) were recorded for the sample EHS₉GO₂ and AA6061, respectively, which showed that EHS₉GO₂ coating had the most hydrophobic behavior. An adhesion test (method B, tape test) was performed on prepared coatings to check the quality of adhesion with the substrate aluminum alloy AA6061. The neat epoxy coating (EHS₀GO₀) displayed a fair adhesion rating of 3B, while EHS₉GO₂ coating exhibited excellent adhesion (5B) with substrate AA6061. Furthermore, electrochemical impedance spectroscopy and potentiodynamic polarization tests were employed for assessing the electrochemical behavior and anticorrosion performance of the prepared coatings. It was observed from the Bode plot, that the impedance magnitude/modulus for EHS₉GO₂ at lower frequencies was the highest as compared to other samples during immersion in the artificial seawater. The bare aluminum alloy substrate AA6061 had the highest corrosion rate of value 0.10483 ± 0.00198 mm/year, due to the direct contact with the electrolyte. Moreover, the highest value of E_corr (356 ± 0.42 mV) and lowest values of I_corr (0.18 ± 0.03µA), β_a (48.7 ± 2 mV/decade), and β_c (28.8 ± 1 mV/decade) were witnessed for EHS₉GO₂ coating, showing significant anticorrosion efficiency against the corrosive electrolyte.

中文翻译：

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深入了解改性 SiO2/GO 基环氧复合涂层对铝合金 AA6061 在海洋应用中的缓蚀功效

摘要

铝合金的腐蚀防护受到海洋环境的严重影响，需要配制高效的防护涂层。采用环氧树脂、双酚A二缩水甘油醚(DGEBA)和固化剂二亚乙基三胺(DETA)以100:12的比例合成功能化SiO ₂ /GO基复合涂层并研究其对铝合金AA6061的腐蚀防护效果。在海洋环境中。为了提高涂层的阻隔和防腐性能，将功能化二氧化硅（FSiO ₂，重量百分比为 0、3、6、9、12 和 15%）和氧化石墨烯 (GO) 联合纳入 DGEBA/DETA 环氧固化剂体系中用于生产复合涂料。根据傅里叶变换红外光谱证据，使用 3-氨丙基三乙氧基硅烷对二氧化硅颗粒进行功能化并合成 GO 已成功进行。通过X射线衍射研究了结构特性。进行疏水性测试以测量接触角。样品EHS ₉ GO ₂和AA6061 分别记录到最高静态接触角（126°±2）和最低接触角（74°±1.5），这表明EHS ₉ GO ₂涂层具有最强的疏水行为。对制备的涂层进行附着力测试（方法B，胶带测试）以检查与基材铝合金AA6061的附着力质量。纯环氧涂层 (EHS ₀ GO ₀ ) 显示出 3B 的良好附着力等级，而 EHS ₉ GO ₂涂层与基材 AA6061 表现出优异的附着力 (5B)。此外，采用电化学阻抗谱和动电位极化测试来评估所制备涂层的电化学行为和防腐性能。从波特图观察到，在浸入人造海水期间，与其他样品相比， EHS ₉ GO ₂在较低频率下的阻抗幅度/模量是最高的。由于直接与电解液接触，裸露的铝合金基材AA6061的腐蚀速率最高，为0.10483±0.00198毫米/年。此外， E _corr的最高值(356 ± 0.42 mV) 和I _corr的最低值(0.18 ± 0.03μA)、β _a (48.7 ± 2 mV/decade) 和β _c (28.8 ± 1 mV/decade) 分别为EHS ₉ GO ₂涂层得到了证实，对腐蚀性电解液表现出显着的防腐效率。