Abstract

Cerium-containing microcapsules were obtained by means of water/oil (W/O) emulsion technology using tetraethyl orthosilicate (TEOS) as the precursor. Synthesis parameters as water/ethanol molar ratio, surfactant concentration, temperature, synthesis time, were optimized to obtain microcapsules with adequate form and size. Cerium salt is a corrosion inhibitor. Scanning electron microscopy (SEM) was employed to characterize the microcapsules and EDS and energy dispersive X-ray (EDX) microanalysis to assess encapsulation of cerium. The synthesized microcapsules were incorporated in the sol–gel coating that was sprayed on AA2024 aluminum alloy. The morphology of the sol–gel coating and the distribution of the microcapsules were investigated by SEM and EDX and the corrosion resistance of the coated samples was evaluated by electrochemical impedance spectroscopy (EIS) and open circuit potential measurements. Cerium microcapsules can act as Ce nanoreservoirs blocking defects produced in the organic–inorganic hybrid coating by precipitating Ce oxide/hydroxide and nanoloads slowing the diffusion of redox species to the aluminum surface. Higher corrosion resistance was obtained with microencapsulation of cerium than with nonencapsulated cerium.

Synthesized microcapsules containing Ce(NO₃)₃ and incorporated in the sol-gel formulation to provide corrosion protection to AA2024 alloy.

中文翻译：

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铈的微囊化及其在溶胶凝胶涂层中对铝合金AA2024的腐蚀防护

摘要

借助于水/油（W / O）乳液技术，使用原硅酸四乙酯（TEOS）作为前体获得含铈的微胶囊。优化了合成参数，如水/乙醇摩尔比，表面活性剂浓度，温度，合成时间，以获得具有适当形式和大小的微胶囊。铈盐是一种腐蚀抑制剂。扫描电子显微镜（SEM）用于表征微胶囊，EDS和能量分散X射线（EDX）微观分析，以评估铈的封装。将合成的微囊掺入喷涂在AA2024铝合金上的溶胶-凝胶涂层中。通过SEM和EDX研究了溶胶-凝胶涂层的形态和微囊的分布，并通过电化学阻抗谱（EIS）和开路电势测量评估了涂层样品的耐蚀性。铈微胶囊可充当Ce纳米储库，通过沉淀Ce氧化物/氢氧化物来阻止有机-无机杂化涂层中产生的缺陷，而纳米负载可减慢氧化还原物质向铝表面的扩散。微封装的铈比未封装的铈具有更高的耐腐蚀性。铈微胶囊可充当Ce纳米储库，通过沉淀Ce氧化物/氢氧化物来阻止有机-无机杂化涂层中产生的缺陷，而纳米负载可减慢氧化还原物质向铝表面的扩散。微封装的铈比未封装的铈具有更高的耐腐蚀性。铈微胶囊可作为Ce纳米储库，通过沉淀Ce氧化物/氢氧化物来阻止有机-无机杂化涂层中产生的缺陷，纳米负载减慢了氧化还原物质向铝表面的扩散。微封装的铈比未封装的铈具有更高的耐腐蚀性。