Micron Scale Cathodically Coated Graphene Impedes Corrosion on Ti, Cube, and Stainless Steel

Graphene has been studied with great interest ever since its unique mechanical and electronic properties were reported a little more than a decade ago. Common experiments involve coating non-carbon surfaces such as paper, 1 metal oxide nanoparticles, 2 or nickel 3 in order to either increase their conductivity, or to make them resistant to corrosion. Coating processes often involve mechanical transfer of graphene or chemical reduction of graphene oxide to graphene, but sometimes electrochemical cathodic reduction of the graphene oxide is used in the coating process. Here we report the first instance of cathodically coated Ti metal along with cathodically coated stainless steel and copper-beryllium. We report Raman microscope images to verify complete surface coverage of Ti, and partial coverage of ~2 micron islands of graphene on both stainless steel and CuBe. We also report Tafel plotted voltammograms to show that the presence of graphene on Ti shifts the potential of zero current, normally called the “corrosion potential,” in 3.5% NaCl(aq) to a value positive of the formal potential for the O 2 /H 2 O redox couple in sea water. We also present Tafel plots which show that the corrosion potential of graphene coated CuBe has shifted positive by 0.1V and the corrosion current decreased by nearly an order of magnitude, and that the corrosion potential of graphene coated stainless steel has shifted positive by 0.3V. 1. Parvez, Khaled; Wu, Zhong-Shuai; Li, Rongjin; Liu, Xianjie; Graf, Robert; Feng, Xinliang; and Mullen, Klaus. “Exfoliation of Graphite into Graphene in Aqueous Solutions of Inorganic Salts”. Journal of the American Chemical Society (2014) vol 136, iss 16, pp 6083-6091. 2. Nguyen-Phan, Thuy-Duong; Pham, Viet Hung; Shin, Eun Woo; Pham, Hai-Dinh; Kim, Sunwook; Chung, Jin Suk; Kim, Eui Jung; and Hur, Seung Hyun. “The role of graphene oxide content on the adsorption-enhanced photocatalysis of titanium dioxide/graphene oxide composites”. Chemical Engineering Journal (2011) vol 170, iss 1, pp 226-232. 3. Prasai, Dhiraj; Tuberquia, Juan Carlos; Harl, Robert R.; Jennings, G. Kane; and Lolotin, Kirill I. “Graphene: Corrosion-Inhibiting Coating”. ACS Nano (2012) vol 6, iss 2, pp 1102-1108.