(666e) Electrochemically Triggered Nucleation and Growth of Zinc Phosphate Co-Deposited with Amino-Modified Graphene Oxide

Electrochemically assisted phosphating has been proposed and investigated for decades because of its energy efficient and eco-friendly. Herein, graphene oxide (GO) is first grafted with vinyl group through the reaction with Triethoxyvinylsilane. Then, the vinyl group modified GO is further reacted with [2-(Methacryloyloxy)ethyl]trimethylammonium chloride, incorporating amino group into GO sheets(AGO). Due to the incorporated amino groups, AGO sheets are positively charged in water and thus can be stably dispersed in the electrolyte that containing various ions under strong acid condition. After that, AGO is added to the electrolyte solution as modifier of the electrochemical phosphating process, and then co-deposited with phosphate coating on the steel substrate. The morphology and chemical composition of AGO modified phosphate coating are characterized via scanning electron microscopy and X-ray diffraction. Based on that, the possible mechanism of the AGO assisted electrochemical phosphating is proposed. Electrochemical measurements, including polarization curves and electrochemical impedance spectroscopy (EIS), are then used to evaluate the corrosion inhibitive properties of AGO modified phosphate coating.