Ambrosi Adriano, Pumera Martin
Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore).
Chemistry. 2015 May 18;21(21):7896-901. doi: 10.1002/chem.201406238. Epub 2015 Apr 2.
Corrosion of engineered structures is a major problem causing an estimated economic loss of more than 2 trillion US dollars annually worldwide. Graphene has recently emerged as highly promising, low-cost, and transparent anticorrosion coating material. Herein, it is shown that a multilayer graphene film grown on Ni by chemical vapor deposition undergoes abrupt stability failure under galvanic-corrosion conditions. The multilayer graphene coating was examined by optical microscopy, SEM, energy dispersive X-ray spectroscopy, Raman spectroscopy, and cyclic voltammetry after exposure to potentials between 600 and 1300 mV in alkaline solution. A fast and simple electrochemical method is proposed to sensitively quantify the damage caused by the applied potential bias. It is based on quantification of the oxidation signals generated by the underlying Ni-metal catalyst that is exposed by damage to the graphene film. It is shown that film damage can start at potentials as low as 900 mV and that macroscopic and extensive damage can be caused at potentials above 1000 mV. In addition, once the graphene film has been damaged, the corrosion rate of the underlying metal is significantly increased. These findings are of great importance for potential applications of multilayer graphene films in coating metal structures with huge industrial and economic implications.
工程结构的腐蚀是一个重大问题，据估计，全球每年因此造成的经济损失超过2万亿美元。石墨烯最近已成为一种极具前景、低成本且透明的防腐涂层材料。在此，研究表明，通过化学气相沉积在镍上生长的多层石墨烯膜在电偶腐蚀条件下会突然发生稳定性失效。在碱性溶液中暴露于600至1300毫伏的电位后，通过光学显微镜、扫描电子显微镜、能量色散X射线光谱、拉曼光谱和循环伏安法对多层石墨烯涂层进行了检测。提出了一种快速简便的电化学方法，以灵敏地量化施加的电位偏置所造成的损伤。它基于对由石墨烯膜损伤而暴露的底层镍金属催化剂产生的氧化信号的量化。结果表明，膜损伤可在低至900毫伏的电位下开始，而在高于1000毫伏的电位下会造成宏观且广泛的损伤。此外，一旦石墨烯膜受损，底层金属的腐蚀速率会显著增加。这些发现对于多层石墨烯膜在具有巨大工业和经济意义的金属结构涂层中的潜在应用极为重要。
