Chang Wei, Popov Branko N, Li Chen
Department of Mechanical Engineering, University of South Carolina Columbia SC 29208 USA
Department of Chemical Engineering, University of South Carolina Columbia SC 29208 USA.
RSC Adv. 2021 Nov 10;11(57):36354-36359. doi: 10.1039/d1ra06561k. eCollection 2021 Nov 4.
Graphene grown on metal substrates has been reported to provide efficient and robust hydrophobicity during water vapor condensation on metal surfaces. However, due to the intrinsic negative coefficient of thermal expansion (CTE) of graphene, the potential thermal stress in real application environments can cause CTE mismatch and then damage the protective graphene coatings, leading to loss of surface hydrophobicity and anticorrosion properties. In this study, the effect of thermal treatments on anticorrosion properties and subsequent hydrophobicity of the graphene surface has been investigated. The as-grown graphene on nickel (Ni-Gr) is explored in terms of survival under severe thermal cycling (up to 14.62 °C s) and effectively maintains its surface properties. As a comparison, the as-grown graphene on copper (Cu-Gr) easily peeled off from the metal surface due to the thermal stress and intercalation of oxides. The thermal treatment at 200 °C under ambient atmosphere can elevate the corrosion rate 2.2 times and 29 times on the Ni-Gr and Cu-Gr surfaces compared to situations without thermal treatments, respectively. This study shows that the Ni-Gr surface is significantly more robust than the Cu-Gr surface as a sustainable hydrophobic surface in a complicated thermal environment.
据报道，生长在金属基底上的石墨烯在金属表面水蒸气凝结过程中能提供高效且稳定的疏水性。然而，由于石墨烯固有的负热膨胀系数（CTE），实际应用环境中的潜在热应力会导致CTE不匹配，进而损坏保护性石墨烯涂层，导致表面疏水性和防腐性能丧失。在本研究中，研究了热处理对石墨烯表面防腐性能及后续疏水性的影响。对生长在镍上的石墨烯（Ni-Gr）在剧烈热循环（高达14.62℃/s）下的存活情况进行了探索，其有效地保持了表面性能。作为对比，生长在铜上的石墨烯（Cu-Gr）由于热应力和氧化物的嵌入而容易从金属表面剥离。与未进行热处理的情况相比，在环境气氛下200℃的热处理分别使Ni-Gr和Cu-Gr表面的腐蚀速率提高了2.2倍和29倍。本研究表明，在复杂热环境中，作为可持续疏水表面，Ni-Gr表面比Cu-Gr表面明显更稳定。
