Xu Ying, Qu Jingyi, Shen Yongtao, Feng Wei
School of Materials Science and Engineering, Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials Tianjin 300072 P. R China
Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin Key Laboratory of Composite and Functional Materials Tianjin 300072 P. R China.
RSC Adv. 2018 Apr 23;8(27):15181-15187. doi: 10.1039/c8ra00412a. eCollection 2018 Apr 18.
Graphene was used as an anticorrosive coating for metals as it can effectively isolate the corrosion factors such as oxygen. However, we found that the anticorrosive and corrosive effects on metal surface were related to graphene layers and metal crystal faces. In this paper, we found that different layers of graphene had significantly different effects on the corrosion of polycrystalline copper during long-term storage under atmospheric conditions. Optical images and Raman spectra showed that single layer graphene (SLG)-coated copper had a higher degree of corrosion than bare copper. However, when covered with CVD -grown bilayer graphene (BLG), the copper foil was effectively prevented from being etched as it exhibited a bright yellow color despite the differences in crystal faces. The surface potential differences measured by an electric force microscope (EFM) showed that a contact potential difference ( ) between 30 and 40 mV existed between Cu/SLG and bare copper. The SLG-coated areas had a higher surface potential (SP), which meant that the (SLG)-coated copper was more prone to lose electrons to exhibit galvanic corrosion. The BLG coating made SP of underlying copper lower making it harder to lose electrons; thus, BLG successfully protected the copper from being corroded. These findings have a foreseeable significance for graphene as a metal anti-corrosion coating.
石墨烯被用作金属的防腐涂层，因为它可以有效隔离诸如氧气等腐蚀因素。然而，我们发现石墨烯对金属表面的防腐和腐蚀作用与石墨烯层数以及金属晶面有关。在本文中，我们发现不同层数的石墨烯在大气条件下长期储存期间对多晶铜的腐蚀有显著不同的影响。光学图像和拉曼光谱表明，单层石墨烯（SLG）包覆的铜比裸铜具有更高的腐蚀程度。然而，当覆盖有化学气相沉积（CVD）生长的双层石墨烯（BLG）时，铜箔尽管晶面存在差异，但仍呈现亮黄色，从而有效地防止了被蚀刻。通过电力显微镜（EFM）测量的表面电位差表明，Cu/SLG与裸铜之间存在30至40 mV的接触电位差（ ）。SLG包覆区域具有更高的表面电位（SP），这意味着SLG包覆的铜更容易失去电子以表现出电偶腐蚀。BLG涂层使下层铜的SP降低，使其更难失去电子；因此，BLG成功地保护了铜不被腐蚀。这些发现对于石墨烯作为金属防腐涂层具有可预见的意义。
