Self-assembly of exfoliated graphene flakes as anticorrosive coatings for additive manufactured steels
Self-assembly of exfoliated graphene flakes as anticorrosive coatings for additive manufactured steels
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DOI：
10.1016/j.rsurfi.2023.100116
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发表时间：
2023-05
影响因子：
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通讯作者：
Kaleb Hood;Wen Qian;Yi Xia;Savannah Krupa;Annie Dao;Sarah Ahmed;Samuel Olsen;Nam Ngyun;J. Turner;J. Jiao
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文献类型：
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作者：
Kaleb Hood;Wen Qian;Yi Xia;Savannah Krupa;Annie Dao;Sarah Ahmed;Samuel Olsen;Nam Ngyun;J. Turner;J. Jiao
该研究证明了使用可膨胀石墨的液体剥离成多层剥离的石墨烯薄片（EGFs）以在空气-水界面上形成自组装薄膜的可行性。该膜可以涂覆增材制造（AM）钢基材的表面以增强表面性能，特别是AM 316不锈钢（AM 316）、AM 8620钢（AM 8620）和通过常规制造（CM）工艺制成的相同合金的样品。液体去角质为EGF涂层提供了一种高产率的途径，单次应用可覆盖高达95%的样品表面。薄的柔性EGF可以涂覆粗糙的AM金属表面，而高度完整的晶格保护覆盖区域免受扩散离子的影响，并与用氧化石墨烯（GO）或还原GO（rGO）制成的类似涂层相比防止局部腐蚀。EGF涂层利用了独特的自组装过程，没有表面活性剂或稳定剂，其中EGF的疏水性和亲水性排列薄片，然后货车德瓦尔斯（vdW）力将它们结合在一起并结合到基材上，形成连贯的防腐涂层。电化学测量表明涂层样品的腐蚀电位较低，纳米压痕测量显示表面硬度保护免受腐蚀攻击，和重量损失测量表明长期的保护能力。使用石墨烯和铁（111）界面的optB 88-vdW交换泛函的密度泛函理论计算表明，与充分研究的石墨烯/镍（111）界面相比，石墨烯和铁（111）界面具有更强的结合和更短的界面距离。这些计算和实验结果进一步阐明了EGF薄膜在高铁钢，特别是增材制造钢上的上级性能。
This study demonstrates the feasibility of using liquid exfoliation of expandable graphite into multilayer exfoliated graphene flakes (EGFs) to form a self-assembled thin film on an air–water interface. The film can coat the surface of additive manufactured (AM) steel substrates to enhance surface properties, specifically AM 316 stainless-steel (AM316), AM 8620 steel (AM8620), and samples of the same alloys made by conventional manufacturing (CM) processes. Liquid exfoliation offers a high yield route for an EGF coating that can cover up to 95% of the sample surface with a single application. The thin, flexible EGFs can coat a rough AM metal surface, while the highly intact crystal lattice protects covered areas against diffusing ions and prevents localized corrosion compared to similar coatings made with graphene oxide (GO) or reduced GO (rGO). The EGF coating exploits a unique self-assembly process without surfactants or stabilizers, wherein the hydrophobicity and hydrophilicity of EGFs arrange the flakes, then van der Waals (vdW) forces bond them together and to the substrate for a coherent anti-corrosive coating. Electrochemical measurements indicate lower corrosion potential for coated samples, nanoindentation measurements show surface hardness protection against corrosive attack, and weight loss measurements demonstrate long-term protective capabilities. Density functional theory calculations, using the optB88-vdW exchange functional of the graphene and iron (111) interface demonstrated stronger binding and shorter interface distance compared to the well-studied graphene/nickel (111) interface. These calculations and experimental results can further elucidate the superior performance of EGF thin film coatings on high iron content steels, especially AM steels.